[libpng16] Imported from libpng-1.6.15beta02.tar

[libpng16] More cosmetic changes
[libpng16] Added a pair of parentheses suggested by clang
2025-07-10 18:04:09 +02:00 · 2014-11-01 18:59:08 -05:00 · 2014-11-01 13:18:36 -05:00 · 2014-10-31 21:17:11 -05:00 · 2014-10-31 20:58:40 -05:00 · 2014-10-29 09:13:06 -05:00
48 changed files with 1430 additions and 1292 deletions
--- a/53
+++ b/53
@@ -1,54 +1,37 @@
-Libpng 1.6.13 - August 21, 2014
+Libpng 1.6.15beta02 - November 1, 2014

-This is a public release of libpng, intended for use in production codes.
+This is not intended to be a public release.  It will be replaced
+within a few weeks by a public version or by another test version.

 Files available for download:

 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   libpng-1.6.13.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.13.tar.gz
+   1.6.15beta02.tar.xz (LZMA-compressed, recommended)
+   1.6.15beta02.tar.gz

 Source files with CRLF line endings (for Windows), without the
 "configure" script

-   lpng1613.7z  (LZMA-compressed, recommended)
-   lpng1613.zip
+   lp1615b02.7z  (LZMA-compressed, recommended)
+   lp1615b02.zip

 Other information:

-   libpng-1.6.13-README.txt
-   libpng-1.6.13-LICENSE.txt
-   libpng-1.6.13-*.asc (armored detached GPG signatures)
+   1.6.15beta02-README.txt
+   1.6.15beta02-LICENSE.txt
+   libpng-1.6.15beta02-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.12):
+Changes since the last public release (1.6.14):

-  Quieted -Wsign-compare and -Wclobber compiler warnings in
-    contrib/pngminus/*.c
-  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
-    compiler complaints about unused pointers.
-  Split a long output string in contrib/gregbook/rpng2-x.c.
-  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
-    Needed for write-only support (John Bowler).
-  Changed "if defined(__ARM_NEON__)" to
-    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
-  Fixed clang no-warning builds: png_digit was defined but never used.
-  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
-    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
-    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
-    makefile.tc3 similarly.
-  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
-    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
-    definitions from pngconf.h.
-  Ensure that CMakeLists.txt makes the target "lib" directory before making
-    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
-  Added opinion that the ECCN (Export Control Classification Number) for
-    libpng is EAR99 to the README file.
-  Eliminated use of "$<" in makefile explicit rules, when copying
-    $PNGLIBCONF_H_PREBUILT.  This does not work on some versions of make;
-    bug introduced in libpng version 1.6.11.
-  Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/65
+++ b/65
@@ -4430,7 +4430,7 @@ Version 1.6.1beta05 [March 1, 2013]
 Version 1.6.1beta06 [March 4, 2013]
  Better documentation of unknown handling API interactions.
  Corrected Android builds and corrected libpng.vers with symbol
-    prefixing This adds an API to set optimization options externally,
+    prefixing. This adds an API to set optimization options externally,
    providing an alternative and general solution for the non-portable
    run-time tests used by the ARM Neon code.  It also makes those tests
    compile and link on Android.
@@ -4978,6 +4978,69 @@ Version 1.6.13rc01 [August 14, 2014]
 Version 1.6.13 [August 21, 2014]
  No changes.

+Version 1.6.14beta01 [September 14, 2014]
+  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
+  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
+    to allow "make" to complete without setjmp support (bug report by
+    Claudio Fontana)
+  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
+
+Version 1.6.14beta02 [September 18, 2014]
+  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
+    because usleep() is deprecated.
+  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
+    in unistd.h and nanosleep() is not available; fixes error introduced
+    in libpng-1.6.13.
+  Disable floating point exception handling in pngvalid.c when
+    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
+    at users.sourceforge.net").
+
+Version 1.6.14beta03 [September 19, 2014]
+  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
+    already defined.  Revert floating point exception handling in pngvalid.c
+    to version 1.6.14beta01 behavior.
+
+Version 1.6.14beta04 [September 27, 2014]
+  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
+    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
+
+Version 1.6.14beta05 [October 1, 2014]
+  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
+
+Version 1.6.14beta06 [October 5, 2014]
+  Removed unused "text_len" parameter from private function png_write_zTXt().
+  Conditionally compile some code in png_deflate_claim(), when
+    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
+  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
+  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
+    to pnglibconf.dfa.
+  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
+    to make it possible to configure a libpng that supports iCCP but not TEXT.
+
+Version 1.6.14beta07 [October 7, 2014]
+  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+  Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+  Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+    in the manual, to reflect the change made in libpng-1.6.0.
+  Updated README file to explain that direct access to the png_struct
+    and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+  No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 13)
+set(PNGLIB_RELEASE 15)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -253,7 +253,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.13
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.15beta02
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
--- a/50
+++ b/50
@@ -18,7 +18,7 @@ VIII. Configuring libpng for 16-bit platforms
 XIII. Removing unwanted object code
 XIV. Changes to the build and configuration of libpng in libpng-1.5.x
  XV. Configuring libpng for multiprocessing
- XVI. Other sources of information about libpng:
+ XVI. Other sources of information about libpng

 I. Simple installation

@@ -32,6 +32,15 @@ and ignore the rest of this document.  "/path" is the path to the directory
 where you want to install the libpng "lib", "include", and "bin"
 subdirectories.

+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
 II. Rebuilding the configure scripts

 If configure does not work on your system, or if you have a need to
@@ -111,8 +120,7 @@ Your directory structure should look like this:
      libpng  (this directory)
          INSTALL (this file)
          README
-          *.h
-          *.c
+          *.h, *.c  => libpng source files
          CMakeLists.txt    =>  "cmake" script
          configuration files:
             configure.ac, configure, Makefile.am, Makefile.in,
@@ -120,15 +128,10 @@ Your directory structure should look like this:
             libpng-config.in, aclocal.m4, config.h.in, config.sub,
             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
          contrib
-             gregbook
-             libtests
-             pngminim
-             pngminus
-             pngsuite
-             visupng
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
          projects
-             visualc71
-             vstudio
+             cbuilder5, owatcom, visualc71, vstudio, xcode
          scripts
             makefile.*
             *.def (module definition files)
@@ -136,11 +139,7 @@ Your directory structure should look like this:
          pngtest.png
          etc.
      zlib
-          README
-          *.h
-          *.c
-          contrib
-          etc.
+          README, *.h, *.c contrib, etc.

 If the line endings in the files look funny, you may wish to get the other
 distribution of libpng.  It is available in both tar.gz (UNIX style line
@@ -149,7 +148,7 @@ endings) and zip (DOS style line endings) formats.
 VI. Building with project files

 If you are building libpng with MSVC, you can enter the
-libpng projects\visualc6 or visualc71 directory and follow the instructions
+libpng projects\visualc71 or vstudio directory and follow the instructions
 in README.txt.

 Otherwise enter the zlib directory and follow the instructions in zlib/README,
@@ -333,7 +332,7 @@ built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
 after the build of pnglibconf.h and it is never included in an application
 build.

-The rarely used alternative of adding a list of feature macros to the
+The formerly used alternative of adding a list of feature macros to the
 CPPFLAGS setting in the build also still works; however, the macros will be
 copied to pnglibconf.h and this may produce macro redefinition warnings
 when the individual C files are compiled.
@@ -349,12 +348,19 @@ functioning awk called 'nawk'.

 Configuration options are now documented in scripts/pnglibconf.dfa.  This
 file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed.  As a recommended alternative to using feature macros in
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
 pngusr.h a system builder may also define equivalent options in pngusr.dfa
 (or, indeed, any file) and add that to the configuration by setting
 DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and illustrate a case where pngusr.h is still required.
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.

 XV. Configuring libpng for multiprocessing

@@ -388,7 +394,7 @@ CFLAGS="-Wall -O -funroll-loops \
 --with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include

 You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng%NN%, or whatever.
+/usr/include/libpng16, or whatever.

 If you find that the configure script is out-of-date or is not supporting
 your platform properly, try running autogen.sh to regenerate "configure",
--- a/4
+++ b/4
@@ -10,7 +10,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.13, August 21, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.15beta02, November 1, 2014, are
 Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -108,4 +108,4 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-August 21, 2014
+November 1, 2014
--- a/21
+++ b/21
@@ -1,4 +1,4 @@
-README for libpng version 1.6.13 - August 21, 2014 (shared library 16.0)
+README for libpng version 1.6.15beta02 - November 1, 2014 (shared library 16.0)
 See the note about version numbers near the top of png.h

 See INSTALL for instructions on how to install libpng.
@@ -23,18 +23,25 @@ earlier versions if you are using a shared library.  The type of the
 png_uint_32, which will affect shared-library applications that use
 this function.

-To avoid problems with changes to the internals of png_info_struct,
+To avoid problems with changes to the internals of png info_struct,
 new APIs have been made available in 0.95 to avoid direct application
 access to info_ptr.  These functions are the png_set_<chunk> and
 png_get_<chunk> functions.  These functions should be used when
 accessing/storing the info_struct data, rather than manipulating it
 directly, to avoid such problems in the future.

-It is important to note that the APIs do not make current programs
+It is important to note that the APIs did not make current programs
 that access the info struct directly incompatible with the new
-library.  However, it is strongly suggested that new programs use
-the new APIs (as shown in example.c and pngtest.c), and older programs
-be converted to the new format, to facilitate upgrades in the future.
+library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
+be a transitional release, members of the png_struct and the
+info_struct can still be accessed, but the compiler will issue a
+warning about deprecated usage.  Since libpng-1.5.0, direct access
+to these structs is not allowed, and the definitions of the structs
+reside in private pngstruct.h and pnginfo.h header files that are not
+accessible to applications.  It is strongly suggested that new
+programs use the new APIs (as shown in example.c and pngtest.c), and
+older programs be converted to the new format, to facilitate upgrades
+in the future.
 ****

 Additions since 0.90 include the ability to compile libpng as a
@@ -183,7 +190,7 @@ Files in this distribution:
       pngminus         =>  Simple pnm2png and png2pnm programs
       pngsuite         =>  Test images
       tools            =>  Various tools
-       visupng      =>  Contains a MSVC workspace for VisualPng
+       visupng          =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for
                        building a DLL
       owatcom          =>  Contains a WATCOM project for building libpng
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.13],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.15beta02],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -39,10 +39,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake

-PNGLIB_VERSION=1.6.13
+PNGLIB_VERSION=1.6.15beta02
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=13
+PNGLIB_RELEASE=15

 dnl End of version number stuff

--- a/contrib/gregbook/rpng2-x.c
+++ b/contrib/gregbook/rpng2-x.c
@@ -103,9 +103,6 @@
 #define RESNAME   "rpng2"       /* our X resource application name */
 #define RESCLASS  "Rpng"       /* our X resource class name */

-/* This is temporary until the code is rewritten to use nanosleep(). */
-#define usleep(x) sleep(((x)+499999)/1000000)
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
@@ -118,6 +115,18 @@
 #include <X11/Xos.h>
 #include <X11/keysym.h>   /* defines XK_* macros */

+#if _POSIX_C_SOURCE >= 199309L /* have nanosleep() */
+# undef usleep
+# define usleep(usec) {        \
+   struct timespec ts;         \
+   ts.tv_nsec = (usec) * 1000; \
+   nanosleep(&ts, NULL); }
+#  endif
+
+#ifndef usleep /* have neither nanosleep() nor usleep() */
+#  define usleep(x) sleep(((x)+499999)/1000000)
+#endif
+
 #ifdef VMS
 #  include <unistd.h>
 #endif
--- a/contrib/libtests/fakepng.c
+++ b/contrib/libtests/fakepng.c
@@ -52,6 +52,6 @@ main(void)
   fwrite(signature, sizeof signature, 1, stdout);
   put_chunk(IHDR, sizeof IHDR);

-   for(;;)
+   for (;;)
      put_chunk(unknown, sizeof unknown);
 }
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,7 +1,7 @@

 /* pngvalid.c - validate libpng by constructing then reading png files.
 *
- * Last changed in libpng 1.6.10 [March 6, 2014]
+ * Last changed in libpng 1.6.14 [October 23, 2014]
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -34,6 +34,16 @@
 #  include <fenv.h>
 #endif

+#ifndef FE_DIVBYZERO
+#  define FE_DIVBYZERO 0
+#endif
+#ifndef FE_INVALID
+#  define FE_INVALID 0
+#endif
+#ifndef FE_OVERFLOW
+#  define FE_OVERFLOW 0
+#endif
+
 /* Define the following to use this test against your installed libpng, rather
 * than the one being built here:
 */
@@ -686,7 +696,7 @@ static png_uint_32
 random_32(void)
 {

-   for(;;)
+   for (;;)
   {
      png_byte mark[4];
      png_uint_32 result;
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -2,7 +2,7 @@
 *
 * Copyright (c) 2014 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.10 [March 6, 2014]
+ * Last changed in libpng 1.6.14 [October 23, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -49,6 +49,9 @@
 #  error "pngfix will not work with libpng prior to 1.6.3"
 #endif

+#ifdef PNG_SETJMP_SUPPORTED
+#include <setjmp.h>
+
 #if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED)
 /* zlib.h defines the structure z_stream, an instance of which is included
 * in this structure and is required for decompressing the LZ compressed
@@ -4034,3 +4037,12 @@ main(void)
   return 77;
 }
 #endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */
+#else /* No setjmp support */
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without setjmp support\n");
+   return 77;
+}
+#endif /* PNG_SETJMP_SUPPORTED */
+
--- a/example.c
+++ b/example.c
@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Maintained 1998-2014 Glenn Randers-Pehrson
 * Maintained 1996, 1997 Andreas Dilger)
 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -52,7 +52,7 @@ int main(int argc, const char **argv)
      image.version = PNG_IMAGE_VERSION;

      /* The first argument is the file to read: */
-      if (png_image_begin_read_from_file(&image, argv[1]))
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
      {
         png_bytep buffer;

@@ -97,7 +97,7 @@ int main(int argc, const char **argv)
          */
         if (buffer != NULL &&
            png_image_finish_read(&image, NULL/*background*/, buffer,
-               0/*row_stride*/, NULL/*colormap*/))
+               0/*row_stride*/, NULL/*colormap*/) != 0)
         {
            /* Now write the image out to the second argument.  In the write
             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
@@ -105,7 +105,7 @@ int main(int argc, const char **argv)
             * to the 8-bit format.
             */
            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
-               buffer, 0/*row_stride*/, NULL/*colormap*/))
+               buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
            {
               /* The image has been written successfully. */
               exit(0);
@@ -188,13 +188,13 @@ int main(int argc, const char **argv)
 *
 * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
 * significant data loss when 16-bit data is converted to the 8-bit encoding and
- * the current libpng implementation of convertion to 16-bit is also
+ * the current libpng implementation of conversion to 16-bit is also
 * significantly lossy.  The latter will be fixed in the future, but the former
 * is unavoidable - the 8-bit format just doesn't have enough resolution.
 */

 /* If your program needs more information from the PNG data it reads, or if you
- * need to do more complex transformations, or minimise transformations, on the
+ * need to do more complex transformations, or minimize transformations, on the
 * data you read, then you must use one of the several lower level libpng
 * interfaces.
 *
@@ -405,7 +405,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Expand paletted or RGB images with transparency to full alpha channels
    * so the data will be available as RGBA quartets.
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
      png_set_tRNS_to_alpha(png_ptr);

   /* Set the background color to draw transparent and alpha images over.
@@ -417,7 +417,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   png_color_16 my_background, *image_background;

-   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
      png_set_background(png_ptr, image_background,
                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
   else
@@ -454,12 +454,12 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   int intent;

-   if (png_get_sRGB(png_ptr, info_ptr, &intent))
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
   else
   {
      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
         png_set_gamma(png_ptr, screen_gamma, image_gamma);
      else
         png_set_gamma(png_ptr, screen_gamma, 0.45455);
@@ -469,7 +469,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Quantize RGB files down to 8 bit palette or reduce palettes
    * to the number of colors available on your screen.
    */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int num_palette;
      png_colorp palette;
@@ -484,7 +484,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
            MAX_SCREEN_COLORS, NULL, 0);
      }
      /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
      {
         png_uint_16p histogram = NULL;

@@ -503,7 +503,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
   {
      png_color_8p sig_bit_p;

@@ -512,7 +512,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   }

   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
      png_set_bgr(png_ptr);

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
@@ -932,7 +932,7 @@ void write_png(char *file_name /* , ... other image information ... */)
    */

   /* Once we write out the header, the compression type on the text
-    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    * at the end.
    */
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.13 - August 21, 2014
+ libpng version 1.6.15beta02 - November 1, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.13 - August 21, 2014
+ libpng versions 0.97, January 1998, through 1.6.15beta02 - November 1, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -3261,7 +3261,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -5223,12 +5223,15 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
+pngtest) appear in pngpriv.h above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5240,10 +5243,8 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5276,13 +5277,13 @@ Other rules can be inferred by inspecting the libpng source.

 XVI. Y2K Compliance in libpng

-August 21, 2014
+November 1, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.13 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.15beta02 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5298,8 +5299,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "August 21, 2014"
+.TH LIBPNG 3 "November 1, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.13
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.15beta02
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -504,7 +504,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.13 - August 21, 2014
+ libpng version 1.6.15beta02 - November 1, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -515,7 +515,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.13 - August 21, 2014
+ libpng versions 0.97, January 1998, through 1.6.15beta02 - November 1, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -3765,7 +3765,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -5727,12 +5727,15 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
+pngtest) appear in pngpriv.h above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5744,10 +5747,8 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5780,13 +5781,13 @@ Other rules can be inferred by inspecting the libpng source.

 .SH XVI. Y2K Compliance in libpng

-August 21, 2014
+November 1, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.13 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.15beta02 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5802,8 +5803,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
@@ -6028,6 +6030,10 @@ the first widely used release:
 1.6.13beta01-04     16    10613  16.so.16.13[.0]
 1.6.13rc01-02       16    10613  16.so.16.13[.0]
 1.6.13              16    10613  16.so.16.13[.0]
+ 1.6.14beta01-07     16    10614  16.so.16.14[.0]
+ 1.6.14rc01-02       16    10614  16.so.16.14[.0]
+ 1.6.14              16    10614  16.so.16.14[.0]
+ 1.6.15beta01-02     16    10615  16.so.16.15[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6084,7 +6090,7 @@ possible without all of you.

 Thanks to Frank J. T. Wojcik for helping with the documentation.

-Libpng version 1.6.13 - August 21, 2014:
+Libpng version 1.6.15beta02 - November 1, 2014:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6107,7 +6113,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.13, August 21, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.15beta02, November 1, 2014, are
 Copyright (c) 2004,2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -6206,7 +6212,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-August 21, 2014
+November 1, 2014

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "August 21, 2014"
+.TH LIBPNGPF 3 "November 1, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.13
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.15beta02
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "August 21, 2014"
+.TH PNG 5 "November 1, 2014"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@

 /* png.c - location for general purpose libpng functions
 *
- * Last changed in libpng 1.6.12 [June 12, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -14,7 +14,7 @@
 #include "pngpriv.h"

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_13 Your_png_h_is_not_version_1_6_13;
+typedef png_libpng_version_1_6_15beta02 Your_png_h_is_not_version_1_6_15beta02;

 /* Tells libpng that we have already handled the first "num_bytes" bytes
 * of the PNG file signature.  If the PNG data is embedded into another
@@ -115,7 +115,7 @@ png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
 {
   int need_crc = 1;

-   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))
+   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
   {
      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
@@ -124,7 +124,7 @@ png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)

   else /* critical */
   {
-      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
+      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
         need_crc = 0;
   }

@@ -133,7 +133,7 @@ png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
    * following cast is safe.  'uInt' may be no more than 16 bits, so it is
    * necessary to perform a loop here.
    */
-   if (need_crc && length > 0)
+   if (need_crc != 0 && length > 0)
   {
      uLong crc = png_ptr->crc; /* Should never issue a warning */

@@ -179,7 +179,7 @@ png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
   else
      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;

-   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
+   if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
   {
     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
      * we must recompile any applications that use any older library version.
@@ -289,7 +289,7 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
 #  endif
         /* Call the general version checker (shared with read and write code):
          */
-         if (png_user_version_check(&create_struct, user_png_ver))
+         if (png_user_version_check(&create_struct, user_png_ver) != 0)
         {
            png_structrp png_ptr = png_voidcast(png_structrp,
               png_malloc_warn(&create_struct, (sizeof *png_ptr)));
@@ -451,32 +451,32 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_TEXT_SUPPORTED
   /* Free text item num or (if num == -1) all text items */
-   if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
+   if (info_ptr->text != 0 &&
+       ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
   {
      if (num != -1)
      {
-         if (info_ptr->text && info_ptr->text[num].key)
-         {
-            png_free(png_ptr, info_ptr->text[num].key);
-            info_ptr->text[num].key = NULL;
-         }
+         png_free(png_ptr, info_ptr->text[num].key);
+         info_ptr->text[num].key = NULL;
      }

      else
      {
         int i;
+
         for (i = 0; i < info_ptr->num_text; i++)
-             png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
+            png_free(png_ptr, info_ptr->text[i].key);
+
         png_free(png_ptr, info_ptr->text);
         info_ptr->text = NULL;
-         info_ptr->num_text=0;
+         info_ptr->num_text = 0;
      }
   }
 #endif

 #ifdef PNG_tRNS_SUPPORTED
   /* Free any tRNS entry */
-   if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
+   if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->trans_alpha);
      info_ptr->trans_alpha = NULL;
@@ -486,7 +486,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_sCAL_SUPPORTED
   /* Free any sCAL entry */
-   if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
+   if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->scal_s_width);
      png_free(png_ptr, info_ptr->scal_s_height);
@@ -498,20 +498,20 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_pCAL_SUPPORTED
   /* Free any pCAL entry */
-   if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
+   if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->pcal_purpose);
      png_free(png_ptr, info_ptr->pcal_units);
      info_ptr->pcal_purpose = NULL;
      info_ptr->pcal_units = NULL;
+
      if (info_ptr->pcal_params != NULL)
         {
-            unsigned int i;
+            int i;
+
            for (i = 0; i < info_ptr->pcal_nparams; i++)
-            {
               png_free(png_ptr, info_ptr->pcal_params[i]);
-               info_ptr->pcal_params[i] = NULL;
-            }
+
            png_free(png_ptr, info_ptr->pcal_params);
            info_ptr->pcal_params = NULL;
         }
@@ -521,7 +521,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_iCCP_SUPPORTED
   /* Free any profile entry */
-   if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
+   if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->iccp_name);
      png_free(png_ptr, info_ptr->iccp_profile);
@@ -533,26 +533,28 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_sPLT_SUPPORTED
   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
-   if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
+   if (info_ptr->splt_palettes != 0 &&
+       ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
   {
      if (num != -1)
      {
-         if (info_ptr->splt_palettes)
-         {
-            png_free(png_ptr, info_ptr->splt_palettes[num].name);
-            png_free(png_ptr, info_ptr->splt_palettes[num].entries);
-            info_ptr->splt_palettes[num].name = NULL;
-            info_ptr->splt_palettes[num].entries = NULL;
-         }
+         png_free(png_ptr, info_ptr->splt_palettes[num].name);
+         png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+         info_ptr->splt_palettes[num].name = NULL;
+         info_ptr->splt_palettes[num].entries = NULL;
      }

      else
      {
-         if (info_ptr->splt_palettes_num)
+         if (info_ptr->splt_palettes_num != 0)
         {
            int i;
+
            for (i = 0; i < info_ptr->splt_palettes_num; i++)
-               png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, (int)i);
+            {
+               png_free(png_ptr, info_ptr->splt_palettes[i].name);
+               png_free(png_ptr, info_ptr->splt_palettes[i].entries);
+            }

            png_free(png_ptr, info_ptr->splt_palettes);
            info_ptr->splt_palettes = NULL;
@@ -564,25 +566,23 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
 #endif

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
-   if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
+   if (info_ptr->unknown_chunks != 0 &&
+       ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
   {
      if (num != -1)
      {
-          if (info_ptr->unknown_chunks)
-          {
-             png_free(png_ptr, info_ptr->unknown_chunks[num].data);
-             info_ptr->unknown_chunks[num].data = NULL;
-          }
+          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+          info_ptr->unknown_chunks[num].data = NULL;
      }

      else
      {
         int i;

-         if (info_ptr->unknown_chunks_num)
+         if (info_ptr->unknown_chunks_num != 0)
         {
            for (i = 0; i < info_ptr->unknown_chunks_num; i++)
-               png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, (int)i);
+               png_free(png_ptr, info_ptr->unknown_chunks[i].data);

            png_free(png_ptr, info_ptr->unknown_chunks);
            info_ptr->unknown_chunks = NULL;
@@ -594,7 +594,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_hIST_SUPPORTED
   /* Free any hIST entry */
-   if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
+   if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->hist);
      info_ptr->hist = NULL;
@@ -603,7 +603,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
 #endif

   /* Free any PLTE entry that was internally allocated */
-   if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
+   if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
   {
      png_free(png_ptr, info_ptr->palette);
      info_ptr->palette = NULL;
@@ -613,16 +613,14 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_INFO_IMAGE_SUPPORTED
   /* Free any image bits attached to the info structure */
-   if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
+   if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
   {
-      if (info_ptr->row_pointers)
+      if (info_ptr->row_pointers != 0)
      {
         png_uint_32 row;
         for (row = 0; row < info_ptr->height; row++)
-         {
            png_free(png_ptr, info_ptr->row_pointers[row]);
-            info_ptr->row_pointers[row] = NULL;
-         }
+
         png_free(png_ptr, info_ptr->row_pointers);
         info_ptr->row_pointers = NULL;
      }
@@ -750,7 +748,7 @@ png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
   if (png_ptr != NULL)
   {
      /* The only failure above if png_ptr != NULL is from an invalid ptime */
-      if (!png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime))
+      if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
         png_warning(png_ptr, "Ignoring invalid time value");

      else
@@ -773,13 +771,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-     "libpng version 1.6.13 - August 21, 2014" PNG_STRING_NEWLINE \
+     "libpng version 1.6.15beta02 - November 1, 2014" PNG_STRING_NEWLINE \
     "Copyright (c) 1998-2014 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
     "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
     "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
     PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.6.13 - August 21, 2014\
+      return "libpng version 1.6.15beta02 - November 1, 2014\
      Copyright (c) 1998-2014 Glenn Randers-Pehrson\
      Copyright (c) 1996-1997 Andreas Dilger\
      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -904,7 +902,7 @@ png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
   {
      p -= 5;

-      if (!memcmp(chunk_name, p, 4))
+      if (memcmp(chunk_name, p, 4) == 0)
         return p[4];
   }
   while (p > p_end);
@@ -1046,8 +1044,8 @@ png_colorspace_check_gamma(png_const_structrp png_ptr,
   png_fixed_point gtest;

   if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
-      (!png_muldiv(&gtest, colorspace->gamma, PNG_FP_1, gAMA) ||
-      png_gamma_significant(gtest)))
+      (png_muldiv(&gtest, colorspace->gamma, PNG_FP_1, gAMA) == 0  ||
+      png_gamma_significant(gtest) != 0))
   {
      /* Either this is an sRGB image, in which case the calculated gamma
       * approximation should match, or this is an image with a profile and the
@@ -1102,12 +1100,13 @@ png_colorspace_set_gamma(png_const_structrp png_ptr,
 #  endif

   /* Do nothing if the colorspace is already invalid */
-   else if (colorspace->flags & PNG_COLORSPACE_INVALID)
+   else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
      return;

   else
   {
-      if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, 1/*from gAMA*/))
+      if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
+          1/*from gAMA*/) != 0)
      {
         /* Store this gamma value. */
         colorspace->gamma = gAMA;
@@ -1131,7 +1130,7 @@ png_colorspace_set_gamma(png_const_structrp png_ptr,
 void /* PRIVATE */
 png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
 {
-   if (info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
+   if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
   {
      /* Everything is invalid */
      info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
@@ -1152,20 +1151,20 @@ png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
          * it; this allows a PNG to contain a profile which matches sRGB and
          * yet still have that profile retrievable by the application.
          */
-         if (info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB)
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
            info_ptr->valid |= PNG_INFO_sRGB;

         else
            info_ptr->valid &= ~PNG_INFO_sRGB;

-         if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
            info_ptr->valid |= PNG_INFO_cHRM;

         else
            info_ptr->valid &= ~PNG_INFO_cHRM;
 #     endif

-      if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA)
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
         info_ptr->valid |= PNG_INFO_gAMA;

      else
@@ -1198,22 +1197,28 @@ png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
   png_int_32 d, dwhite, whiteX, whiteY;

   d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
-   if (!png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d)) return 1;
+   if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
+      return 1;
   dwhite = d;
   whiteX = XYZ->red_X;
   whiteY = XYZ->red_Y;

   d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
-   if (!png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d)) return 1;
+   if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
+      return 1;
   dwhite += d;
   whiteX += XYZ->green_X;
   whiteY += XYZ->green_Y;

   d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
-   if (!png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d)) return 1;
+   if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
+      return 1;
   dwhite += d;
   whiteX += XYZ->blue_X;
   whiteY += XYZ->blue_Y;
@@ -1221,8 +1226,10 @@ png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
   /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
    * thus:
    */
-   if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1;
-   if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1;
+   if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
+      return 1;
+   if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
+      return 1;

   return 0;
 }
@@ -1425,16 +1432,16 @@ png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
   /* By the argument, above overflow should be impossible here. The return
    * value of 2 indicates an internal error to the caller.
    */
-   if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7))
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
      return 2;
-   if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7))
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
      return 2;
   denominator = left - right;

   /* Now find the red numerator. */
-   if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7))
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
      return 2;
-   if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7))
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
      return 2;

   /* Overflow is possible here and it indicates an extreme set of PNG cHRM
@@ -1442,16 +1449,16 @@ png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
    * scale value because this allows us to delay the multiplication of white-y
    * into the denominator, which tends to produce a small number.
    */
-   if (!png_muldiv(&red_inverse, xy->whitey, denominator, left-right) ||
+   if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
       red_inverse <= xy->whitey /* r+g+b scales = white scale */)
      return 1;

   /* Similarly for green_inverse: */
-   if (!png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7))
+   if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
      return 2;
-   if (!png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7))
+   if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
      return 2;
-   if (!png_muldiv(&green_inverse, xy->whitey, denominator, left-right) ||
+   if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
       green_inverse <= xy->whitey)
      return 1;

@@ -1459,29 +1466,34 @@ png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
    * can still produce 0 for extreme cHRM values.
    */
   blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
-      png_reciprocal(green_inverse);
-   if (blue_scale <= 0) return 1;
+       png_reciprocal(green_inverse);
+   if (blue_scale <= 0)
+      return 1;


   /* And fill in the png_XYZ: */
-   if (!png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse)) return 1;
-   if (!png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse)) return 1;
-   if (!png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
-      red_inverse))
+   if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
+       red_inverse) == 0)
      return 1;

-   if (!png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse))
+   if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
      return 1;
-   if (!png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse))
+   if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
      return 1;
-   if (!png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
-      green_inverse))
+   if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
+       green_inverse) == 0)
      return 1;

-   if (!png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1)) return 1;
-   if (!png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1)) return 1;
-   if (!png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
-      PNG_FP_1))
+   if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
+       PNG_FP_1) == 0)
      return 1;

   return 0; /*success*/
@@ -1503,24 +1515,35 @@ png_XYZ_normalize(png_XYZ *XYZ)
    * safe.
    */
   Y = XYZ->red_Y;
-   if (0x7fffffff - Y < XYZ->green_X) return 1;
+   if (0x7fffffff - Y < XYZ->green_X)
+      return 1;
   Y += XYZ->green_Y;
-   if (0x7fffffff - Y < XYZ->blue_X) return 1;
+   if (0x7fffffff - Y < XYZ->blue_X)
+      return 1;
   Y += XYZ->blue_Y;

   if (Y != PNG_FP_1)
   {
-      if (!png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y)) return 1;
+      if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
+         return 1;

-      if (!png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y)) return 1;
+      if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
+         return 1;

-      if (!png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y)) return 1;
-      if (!png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y)) return 1;
+      if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
+         return 1;
   }

   return 0;
@@ -1530,14 +1553,16 @@ static int
 png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
 {
   /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
-   return !(PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
-      PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
-      PNG_OUT_OF_RANGE(xy1->redx,   xy2->redx,  delta) ||
-      PNG_OUT_OF_RANGE(xy1->redy,   xy2->redy,  delta) ||
-      PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
-      PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
-      PNG_OUT_OF_RANGE(xy1->bluex,  xy2->bluex, delta) ||
-      PNG_OUT_OF_RANGE(xy1->bluey,  xy2->bluey, delta));
+   if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
+       PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
+       PNG_OUT_OF_RANGE(xy1->redx,   xy2->redx,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->redy,   xy2->redy,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
+       PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluex,  xy2->bluex, delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluey,  xy2->bluey, delta))
+      return 0;
+   return 1;
 }

 /* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
@@ -1558,13 +1583,15 @@ png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)

   /* As a side-effect this routine also returns the XYZ endpoints. */
   result = png_XYZ_from_xy(XYZ, xy);
-   if (result != 0) return result;
+   if (result != 0)
+      return result;

   result = png_xy_from_XYZ(&xy_test, XYZ);
-   if (result != 0) return result;
+   if (result != 0)
+      return result;

   if (png_colorspace_endpoints_match(xy, &xy_test,
-      5/*actually, the math is pretty accurate*/))
+       5/*actually, the math is pretty accurate*/) != 0)
      return 0;

   /* Too much slip */
@@ -1581,10 +1608,12 @@ png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
   png_XYZ XYZtemp;

   result = png_XYZ_normalize(XYZ);
-   if (result != 0) return result;
+   if (result != 0)
+      return result;

   result = png_xy_from_XYZ(xy, XYZ);
-   if (result != 0) return result;
+   if (result != 0)
+      return result;

   XYZtemp = *XYZ;
   return png_colorspace_check_xy(&XYZtemp, xy);
@@ -1605,19 +1634,21 @@ png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
   png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
   int preferred)
 {
-   if (colorspace->flags & PNG_COLORSPACE_INVALID)
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
      return 0;

   /* The consistency check is performed on the chromaticities; this factors out
    * variations because of the normalization (or not) of the end point Y
    * values.
    */
-   if (preferred < 2 && (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+   if (preferred < 2 &&
+       (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      /* The end points must be reasonably close to any we already have.  The
       * following allows an error of up to +/-.001
       */
-      if (!png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, 100))
+      if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
+          100) == 0)
      {
         colorspace->flags |= PNG_COLORSPACE_INVALID;
         png_benign_error(png_ptr, "inconsistent chromaticities");
@@ -1636,7 +1667,7 @@ png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
   /* The end points are normally quoted to two decimal digits, so allow +/-0.01
    * on this test.
    */
-   if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000))
+   if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
      colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;

   else
@@ -1764,7 +1795,7 @@ png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
   pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
   pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
   pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
-   if (is_ICC_signature(value))
+   if (is_ICC_signature(value) != 0)
   {
      /* So 'value' is at most 4 bytes and the following cast is safe */
      png_icc_tag_name(message+pos, (png_uint_32)value);
@@ -1825,7 +1856,7 @@ png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
   };

   /* Do nothing if the colorspace is already invalidated. */
-   if (colorspace->flags & PNG_COLORSPACE_INVALID)
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
      return 0;

   /* Check the intent, then check for existing settings.  It is valid for the
@@ -2004,13 +2035,13 @@ png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
   switch (temp)
   {
      case 0x52474220: /* 'RGB ' */
-         if (!(color_type & PNG_COLOR_MASK_COLOR))
+         if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
            return png_icc_profile_error(png_ptr, colorspace, name, temp,
               "RGB color space not permitted on grayscale PNG");
         break;

      case 0x47524159: /* 'GRAY' */
-         if (color_type & PNG_COLOR_MASK_COLOR)
+         if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
            return png_icc_profile_error(png_ptr, colorspace, name, temp,
               "Gray color space not permitted on RGB PNG");
         break;
@@ -2219,10 +2250,12 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
 #endif
   unsigned int i;

+#ifdef PNG_SET_OPTION_SUPPORTED
   /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
   if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
               PNG_OPTION_ON)
      return 0;
+#endif

   for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
   {
@@ -2236,7 +2269,7 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
          * are not used by default if there is an MD5!)
          */
 #        if PNG_sRGB_PROFILE_CHECKS == 0
-            if (png_sRGB_checks[i].have_md5)
+            if (png_sRGB_checks[i].have_md5 != 0)
               return 1+png_sRGB_checks[i].is_broken;
 #        endif

@@ -2276,7 +2309,7 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
                  if (crc == png_sRGB_checks[i].crc)
 #              endif
               {
-                  if (png_sRGB_checks[i].is_broken)
+                  if (png_sRGB_checks[i].is_broken != 0)
                  {
                     /* These profiles are known to have bad data that may cause
                      * problems if they are used, therefore attempt to
@@ -2291,7 +2324,7 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
                   * the profile is perfectly valid, but it would be nice if
                   * people used the up-to-date ones.
                   */
-                  else if (!png_sRGB_checks[i].have_md5)
+                  else if (png_sRGB_checks[i].have_md5 == 0)
                  {
                     png_chunk_report(png_ptr, "out-of-date sRGB profile with"
                        " no signature",
@@ -2329,7 +2362,7 @@ png_icc_set_sRGB(png_const_structrp png_ptr,
    * the sRGB information.
    */
 #if PNG_sRGB_PROFILE_CHECKS >= 0
-   if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler))
+   if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
 #endif
      (void)png_colorspace_set_sRGB(png_ptr, colorspace,
         (int)/*already checked*/png_get_uint_32(profile+64));
@@ -2341,14 +2374,14 @@ png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
   png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
   int color_type)
 {
-   if (colorspace->flags & PNG_COLORSPACE_INVALID)
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
      return 0;

-   if (png_icc_check_length(png_ptr, colorspace, name, profile_length) &&
-      png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
-         color_type) &&
-      png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
-         profile))
+   if (png_icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
+       png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
+          color_type) != 0 &&
+       png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
+          profile) != 0)
   {
 #     ifdef PNG_sRGB_SUPPORTED
         /* If no sRGB support, don't try storing sRGB information */
@@ -2367,7 +2400,7 @@ void /* PRIVATE */
 png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
 {
   /* Set the rgb_to_gray coefficients from the colorspace. */
-   if (!png_ptr->rgb_to_gray_coefficients_set &&
+   if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
      (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      /* png_set_background has not been called, get the coefficients from the Y
@@ -2531,13 +2564,13 @@ png_check_IHDR(png_const_structrp png_ptr,
    * 4. The filter_method is 64 and
    * 5. The color_type is RGB or RGBA
    */
-   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
-       png_ptr->mng_features_permitted)
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
+       png_ptr->mng_features_permitted != 0)
      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");

   if (filter_type != PNG_FILTER_TYPE_BASE)
   {
-      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
          (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
          ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
          (color_type == PNG_COLOR_TYPE_RGB ||
@@ -2547,7 +2580,7 @@ png_check_IHDR(png_const_structrp png_ptr,
         error = 1;
      }

-      if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
      {
         png_warning(png_ptr, "Invalid filter method in IHDR");
         error = 1;
@@ -2607,7 +2640,7 @@ png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
      switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
      {
      case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
-         if (state & PNG_FP_SAW_ANY)
+         if ((state & PNG_FP_SAW_ANY) != 0)
            goto PNG_FP_End; /* not a part of the number */

         png_fp_add(state, type);
@@ -2615,10 +2648,10 @@ png_check_fp_number(png_const_charp string, png_size_t size, int *statep,

      case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
         /* Ok as trailer, ok as lead of fraction. */
-         if (state & PNG_FP_SAW_DOT) /* two dots */
+         if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
            goto PNG_FP_End;

-         else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */
+         else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
            png_fp_add(state, type);

         else
@@ -2627,7 +2660,7 @@ png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
         break;

      case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
-         if (state & PNG_FP_SAW_DOT) /* delayed fraction */
+         if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);

         png_fp_add(state, type | PNG_FP_WAS_VALID);
@@ -2665,7 +2698,7 @@ png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
         break;

      case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
-         if (state & PNG_FP_SAW_ANY)
+         if ((state & PNG_FP_SAW_ANY) != 0)
            goto PNG_FP_End; /* not a part of the number */

         png_fp_add(state, PNG_FP_SAW_SIGN);
@@ -2708,7 +2741,7 @@ png_check_fp_string(png_const_charp string, png_size_t size)
   int        state=0;
   png_size_t char_index=0;

-   if (png_check_fp_number(string, size, &state, &char_index) &&
+   if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
      (char_index == size || string[char_index] == 0))
      return state /* must be non-zero - see above */;

@@ -2962,8 +2995,9 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,

                  if (exp_b10 != (-1))
                  {
-                     if (exp_b10 == 0) *ascii++ = 46, --size; /* counted
-                                                                 above */
+                     if (exp_b10 == 0)
+                        *ascii++ = 46, --size; /* counted above */
+
                     --exp_b10;
                  }
                  *ascii++ = (char)(48 + (int)d), ++cdigits;
@@ -3275,7 +3309,8 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
               result = -result;

            /* Check for overflow. */
-            if ((negative && result <= 0) || (!negative && result >= 0))
+            if ((negative != 0 && result <= 0) ||
+                (negative == 0 && result >= 0))
            {
               *res = result;
               return 1;
@@ -3299,7 +3334,7 @@ png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
 {
   png_fixed_point result;

-   if (png_muldiv(&result, a, times, divisor))
+   if (png_muldiv(&result, a, times, divisor) != 0)
      return result;

   png_warning(png_ptr, "fixed point overflow ignored");
@@ -3320,7 +3355,7 @@ png_reciprocal(png_fixed_point a)
 #else
   png_fixed_point res;

-   if (png_muldiv(&res, 100000, 100000, a))
+   if (png_muldiv(&res, 100000, 100000, a) != 0)
      return res;
 #endif

@@ -3355,7 +3390,7 @@ png_product2(png_fixed_point a, png_fixed_point b)
 #    else
   png_fixed_point res;

-   if (png_muldiv(&res, a, b, 100000))
+   if (png_muldiv(&res, a, b, 100000) != 0)
      return res;
 #    endif

@@ -3569,8 +3604,8 @@ png_log16bit(png_uint_32 x)
 * each case only the low 16 bits are relevant - the fraction - since the
 * integer bits (the top 4) simply determine a shift.
 *
- * The worst case is the 16-bit distinction between 65535 and 65534, this
- * requires perhaps spurious accuracty in the decoding of the logarithm to
+ * The worst case is the 16-bit distinction between 65535 and 65534. This
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
 * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
 * of getting this accuracy in practice.
 *
@@ -3658,7 +3693,7 @@ png_exp8bit(png_fixed_point lg2)
   /* Get a 32-bit value: */
   png_uint_32 x = png_exp(lg2);

-   /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
+   /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
    * second, rounding, step can't overflow because of the first, subtraction,
    * step.
    */
@@ -3692,7 +3727,7 @@ png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
         png_int_32 lg2 = png_log8bit(value);
         png_fixed_point res;

-         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
+         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
            return png_exp8bit(res);

         /* Overflow. */
@@ -3716,7 +3751,7 @@ png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
         png_int_32 lg2 = png_log16bit(value);
         png_fixed_point res;

-         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
+         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
            return png_exp16bit(res);

         /* Overflow. */
@@ -3779,7 +3814,7 @@ png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
      /* The 'threshold' test is repeated here because it can arise for one of
       * the 16-bit tables even if the others don't hit it.
       */
-      if (png_gamma_significant(gamma_val))
+      if (png_gamma_significant(gamma_val) != 0)
      {
         /* The old code would overflow at the end and this would cause the
          * 'pow' function to return a result >1, resulting in an
@@ -3840,7 +3875,7 @@ png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,

   /* 'num' is the number of tables and also the number of low bits of low
    * bits of the input 16-bit value used to select a table.  Each table is
-    * itself index by the high 8 bits of the value.
+    * itself indexed by the high 8 bits of the value.
    */
   for (i = 0; i < num; i++)
      table[i] = (png_uint_16p)png_malloc(png_ptr,
@@ -3892,7 +3927,7 @@ png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,

 /* Build a single 8-bit table: same as the 16-bit case but much simpler (and
 * typically much faster).  Note that libpng currently does no sBIT processing
- * (apparently contrary to the spec) so a 256 entry table is always generated.
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
 */
 static void
 png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
@@ -3901,11 +3936,13 @@ png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
   unsigned int i;
   png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);

-   if (png_gamma_significant(gamma_val)) for (i=0; i<256; i++)
-      table[i] = png_gamma_8bit_correct(i, gamma_val);
+   if (png_gamma_significant(gamma_val) != 0)
+      for (i=0; i<256; i++)
+         table[i] = png_gamma_8bit_correct(i, gamma_val);

-   else for (i=0; i<256; ++i)
-      table[i] = (png_byte)i;
+   else
+      for (i=0; i<256; ++i)
+         table[i] = (png_byte)i;
 }

 /* Used from png_read_destroy and below to release the memory used by the gamma
@@ -3997,7 +4034,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
+     if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
     {
        png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
            png_reciprocal(png_ptr->colorspace.gamma));
@@ -4013,7 +4050,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
  {
     png_byte shift, sig_bit;

-     if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+     if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
     {
        sig_bit = png_ptr->sig_bit.red;

@@ -4033,7 +4070,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
      * Where 'iv' is the input color value and 'ov' is the output value -
      * pow(iv, gamma).
      *
-      * Thus the gamma table consists of up to 256 256 entry tables.  The table
+      * Thus the gamma table consists of up to 256 256-entry tables.  The table
      * is selected by the (8-gamma_shift) most significant of the low 8 bits of
      * the color value then indexed by the upper 8 bits:
      *
@@ -4050,7 +4087,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
     else
        shift = 0; /* keep all 16 bits */

-     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
+     if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
     {
        /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
         * the significant bits in the *input* when the output will
@@ -4070,7 +4107,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
      * 16-bit output because the 8-bit table assumes the result will be reduced
      * to 8 bits.
      */
-     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
+     if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
         png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
         png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
         png_ptr->screen_gamma) : PNG_FP_1);
@@ -4083,7 +4120,7 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
+     if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
     {
        png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
            png_reciprocal(png_ptr->colorspace.gamma));
@@ -4141,7 +4178,7 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
 *
 *    error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
 *
- * In all cases the inexact readings are off by one.
+ * In all cases the inexact readings are only off by one.
 */

 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
@@ -4181,8 +4218,7 @@ const png_uint_16 png_sRGB_table[256] =
   57105,57646,58190,58737,59287,59840,60396,60955,
   61517,62082,62650,63221,63795,64372,64952,65535
 };
-
-#endif /* simplified read only */
+#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */

 /* The base/delta tables are required for both read and write (but currently
 * only the simplified versions.)
@@ -4310,7 +4346,7 @@ png_image_free_function(png_voidp argument)

   /* First free any data held in the control structure. */
 #  ifdef PNG_STDIO_SUPPORTED
-      if (cp->owned_file)
+      if (cp->owned_file != 0)
      {
         FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
         cp->owned_file = 0;
@@ -4334,7 +4370,7 @@ png_image_free_function(png_voidp argument)
   png_free(c.png_ptr, cp);

   /* Then the structures, calling the correct API. */
-   if (c.for_write)
+   if (c.for_write != 0)
   {
 #     ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
         png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.13 - August 21, 2014
+ * libpng version 1.6.15beta02 - November 1, 2014
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -11,7 +11,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.13 - August 21, 2014: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.15beta02 - November 1, 2014: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -203,6 +203,10 @@
 *    1.6.13beta01-04         16    10613  16.so.16.13[.0]
 *    1.6.13rc01-02           16    10613  16.so.16.13[.0]
 *    1.6.13                  16    10613  16.so.16.13[.0]
+ *    1.6.14beta01-07         16    10614  16.so.16.14[.0]
+ *    1.6.14rc01-02           16    10614  16.so.16.14[.0]
+ *    1.6.14                  16    10614  16.so.16.14[.0]
+ *    1.6.15beta01-02         16    10615  16.so.16.15[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -234,7 +238,7 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.13, August 21, 2014, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.15beta02, November 1, 2014, are
 * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 * distributed according to the same disclaimer and license as libpng-1.2.5
 * with the following individual added to the list of Contributing Authors:
@@ -346,13 +350,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    August 21, 2014
+ *    November 1, 2014
 *
 *    Since the PNG Development group is an ad-hoc body, we can't make
 *    an official declaration.
 *
 *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.6.13 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.15beta02 are Y2K compliant.  It is my belief that
 *    earlier versions were also Y2K compliant.
 *
 *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -414,9 +418,9 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.13"
+#define PNG_LIBPNG_VER_STRING "1.6.15beta02"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.13 - August 21, 2014\n"
+     " libpng version 1.6.15beta02 - November 1, 2014\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -424,13 +428,13 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 13
+#define PNG_LIBPNG_VER_RELEASE 15

 /* This should match the numeric part of the final component of
 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
 */

-#define PNG_LIBPNG_VER_BUILD  0
+#define PNG_LIBPNG_VER_BUILD  02

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -447,7 +451,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA

 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
 * We must not include leading zeros.
@@ -455,7 +459,7 @@
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
 */
-#define PNG_LIBPNG_VER 10613 /* 1.6.13 */
+#define PNG_LIBPNG_VER 10615 /* 1.6.15 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -560,7 +564,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
 * do not agree upon the version number.
 */
-typedef char* png_libpng_version_1_6_13;
+typedef char* png_libpng_version_1_6_15beta02;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -2745,6 +2749,8 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 #  endif
 #endif

+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 /*******************************************************************************
 *  SIMPLIFIED API
 *******************************************************************************
@@ -2816,7 +2822,7 @@ typedef struct
 #  define PNG_IMAGE_WARNING 1
 #  define PNG_IMAGE_ERROR 2
   /*
-    * The result is a two bit code such that a value more than 1 indicates
+    * The result is a two-bit code such that a value more than 1 indicates
    * a failure in the API just called:
    *
    *    0 - no warning or error
@@ -3197,6 +3203,7 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
 /*******************************************************************************
 *  END OF SIMPLIFIED API
 ******************************************************************************/
+#endif /* PNG_SIMPLIFIED_{READ|WRITE}_SUPPORTED */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
@@ -3244,19 +3251,18 @@ PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,

 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
   int onoff));
-#endif
+#endif /* PNG_SET_OPTION_SUPPORTED */

 /*******************************************************************************
 *  END OF HARDWARE AND SOFTWARE OPTIONS
 ******************************************************************************/

-/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
- * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt
+/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+ * defs, and in scripts/symbols.def.
 */

 /* The last ordinal number (this is the *last* one already used; the next
- * one to use is one more than this.)  Maintainer, remember to add an entry to
- * scripts/symbols.def as well.
+ * one to use is one more than this.)
 */
 #ifdef PNG_EXPORT_LAST_ORDINAL
  PNG_EXPORT_LAST_ORDINAL(244);
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.13 - August 21, 2014
+ * libpng version 1.6.15beta02 - November 1, 2014
 *
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.6.13 [August 21, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -43,8 +43,8 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
   char msg[16];
   if (png_ptr != NULL)
   {
-      if (png_ptr->flags&
-         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+      if ((png_ptr->flags &
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
      {
         if (*error_message == PNG_LITERAL_SHARP)
         {
@@ -54,7 +54,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
               if (error_message[offset] == ' ')
                  break;

-            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
            {
               int i;
               for (i = 0; i < offset - 1; i++)
@@ -69,7 +69,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),

      else
      {
-         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+         if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
         {
            msg[0] = '0';
            msg[1] = '\0';
@@ -152,7 +152,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
         case PNG_NUMBER_FORMAT_fixed:
            /* Needs five digits (the fraction) */
            mincount = 5;
-            if (output || number % 10 != 0)
+            if (output != 0 || number % 10 != 0)
            {
               *--end = digits[number % 10];
               output = 1;
@@ -189,7 +189,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
      ++count;

      /* Float a fixed number here: */
-      if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
+      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
      {
         /* End of the fraction, but maybe nothing was output?  In that case
          * drop the decimal point.  If the number is a true zero handle that
@@ -219,8 +219,8 @@ png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
   if (png_ptr != NULL)
   {
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if (png_ptr->flags&
-       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+   if ((png_ptr->flags &
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
 #endif
      {
         if (*warning_message == PNG_LITERAL_SHARP)
@@ -361,7 +361,7 @@ png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
 void PNGAPI
 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
   {
 #     ifdef PNG_READ_SUPPORTED
         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
@@ -391,7 +391,7 @@ png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN)
+  if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -404,7 +404,7 @@ png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN)
+  if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -442,7 +442,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
      int c = (int)(chunk_name >> ishift) & 0xff;

      ishift -= 8;
-      if (isnonalpha(c))
+      if (isnonalpha(c) != 0)
      {
         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
@@ -514,7 +514,7 @@ void PNGAPI
 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
    error_message)
 {
-   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
      png_chunk_warning(png_ptr, error_message);

   else
@@ -538,7 +538,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
    * unconditionally does the right thing.
    */
 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
 #  endif

 #  ifdef PNG_READ_SUPPORTED
@@ -552,7 +552,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
 #  endif

 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      else if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
@@ -577,11 +577,12 @@ png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
   memcpy(msg, fixed_message, fixed_message_ln);
   iin = 0;
-   if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
-   {
-      msg[fixed_message_ln + iin] = name[iin];
-      ++iin;
-   }
+   if (name != NULL)
+      while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+      {
+         msg[fixed_message_ln + iin] = name[iin];
+         ++iin;
+      }
   msg[fixed_message_ln + iin] = 0;
   png_error(png_ptr, msg);
 }
@@ -757,7 +758,8 @@ PNG_FUNCTION(void,PNGAPI
 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr)
+   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+       png_ptr->jmp_buf_ptr != NULL)
      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
 #else
   PNG_UNUSED(png_ptr)
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -116,7 +116,8 @@ png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
      {
         png_debug1(1, "in %s retrieval function",
             "png_get_x_pixels_per_meter");
@@ -137,7 +138,8 @@ png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
    info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function",
          "png_get_y_pixels_per_meter");
@@ -157,7 +159,8 @@ png_uint_32 PNGAPI
 png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");

@@ -179,7 +182,8 @@ png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");

@@ -202,10 +206,11 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
    png_const_inforp info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)
-       && info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0
-       && info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX
-       && info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
+       info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
+       info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
+       info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
   {
      png_fixed_point res;

@@ -215,7 +220,7 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
       * range of 0..2^31-1; otherwise the cast might overflow.
       */
      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
-          (png_int_32)info_ptr->x_pixels_per_unit))
+          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
         return res;
   }
 #else
@@ -231,7 +236,8 @@ png_int_32 PNGAPI
 png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");

@@ -250,7 +256,8 @@ png_int_32 PNGAPI
 png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");

@@ -269,7 +276,8 @@ png_int_32 PNGAPI
 png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");

@@ -288,7 +296,8 @@ png_int_32 PNGAPI
 png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");

@@ -328,7 +337,7 @@ ppi_from_ppm(png_uint_32 ppm)
    */
   png_fixed_point result;
   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
-       5000))
+       5000) != 0)
      return result;

   /* Overflow. */
@@ -414,7 +423,8 @@ png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_uint_32 retval = 0;

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "pHYs");

@@ -478,8 +488,9 @@ png_uint_32 PNGAPI
 png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
   png_color_16p *background)
 {
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
-       && background != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
+       background != NULL)
   {
      png_debug1(1, "in %s retrieval function", "bKGD");

@@ -509,7 +520,7 @@ png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
    * consistent.
    */
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM");

@@ -550,7 +561,7 @@ png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
   double *blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");

@@ -598,7 +609,7 @@ png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    png_fixed_point *int_blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");

@@ -635,7 +646,7 @@ png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "cHRM");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      if (white_x != NULL)
         *white_x = info_ptr->colorspace.end_points_xy.whitex;
@@ -670,7 +681,7 @@ png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = info_ptr->colorspace.gamma;
@@ -689,7 +700,7 @@ png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA(float)");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
@@ -709,8 +720,8 @@ png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sRGB");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
-       && file_srgb_intent != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
   {
      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
      return (PNG_INFO_sRGB);
@@ -728,9 +739,10 @@ png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "iCCP");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
-       && name != NULL && compression_type != NULL && profile != NULL &&
-		 proflen != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+       name != NULL && compression_type != NULL && profile != NULL &&
+           proflen != NULL)
   {
      *name = info_ptr->iccp_name;
      *profile = info_ptr->iccp_profile;
@@ -768,8 +780,8 @@ png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "hIST");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
-       && hist != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
   {
      *hist = info_ptr->hist;
      return (PNG_INFO_hIST);
@@ -824,8 +836,9 @@ png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "oFFs");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
-       && offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+       offset_x != NULL && offset_y != NULL && unit_type != NULL)
   {
      *offset_x = info_ptr->x_offset;
      *offset_y = info_ptr->y_offset;
@@ -845,8 +858,9 @@ png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "pCAL");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
-       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
       nparams != NULL && units != NULL && params != NULL)
   {
      *purpose = info_ptr->pcal_purpose;
@@ -872,7 +886,7 @@ png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_fixed_point *width, png_fixed_point *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      /*TODO: make this work without FP support; the API is currently eliminated
@@ -895,7 +909,7 @@ png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, double *width, double *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = atof(info_ptr->scal_s_width);
@@ -911,7 +925,7 @@ png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_charpp width, png_charpp height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = info_ptr->scal_s_width;
@@ -933,7 +947,7 @@ png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "pHYs");

   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs))
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      if (res_x != NULL)
      {
@@ -964,8 +978,8 @@ png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "PLTE");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
-       && palette != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
   {
      *palette = info_ptr->palette;
      *num_palette = info_ptr->num_palette;
@@ -983,8 +997,8 @@ png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sBIT");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
-       && sig_bit != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
   {
      *sig_bit = &(info_ptr->sig_bit);
      return (PNG_INFO_sBIT);
@@ -1027,8 +1041,8 @@ png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "tIME");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
-       && mod_time != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
   {
      *mod_time = &(info_ptr->mod_time);
      return (PNG_INFO_tIME);
@@ -1044,7 +1058,8 @@ png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
 {
   png_uint_32 retval = 0;
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tRNS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "tRNS");

@@ -1121,7 +1136,7 @@ png_get_compression_buffer_size(png_const_structrp png_ptr)
      return 0;

 #  ifdef PNG_WRITE_SUPPORTED
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
 #  endif
   {
 #     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -26,6 +26,13 @@
 #define PNG_READ_iTXt_MODE  7
 #define PNG_ERROR_MODE      8

+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+   { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+   { png_push_save_buffer(png_ptr); return; }
+
 void PNGAPI
 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
    png_bytep buffer, png_size_t buffer_size)
@@ -46,7 +53,7 @@ png_process_data_pause(png_structrp png_ptr, int save)
 {
   if (png_ptr != NULL)
   {
-      /* It's easiest for the caller if we do the save, then the caller doesn't
+      /* It's easiest for the caller if we do the save; then the caller doesn't
       * have to supply the same data again:
       */
      if (save != 0)
@@ -189,23 +196,18 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
   int keep; /* unknown handling method */
 #endif

-   /* First we make sure we have enough data for the 4 byte chunk name
-    * and the 4 byte chunk length before proceeding with decoding the
+   /* First we make sure we have enough data for the 4-byte chunk name
+    * and the 4-byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
-    * sure we have enough data in the buffer for the 4 byte CRC at the
+    * sure we have enough data in the buffer for the 4-byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -219,28 +221,28 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   if (chunk_name == png_IDAT)
   {
-      if (png_ptr->mode & PNG_AFTER_IDAT)
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
-      if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
         png_error(png_ptr, "Missing IHDR before IDAT");

      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-          !(png_ptr->mode & PNG_HAVE_PLTE))
+          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
         png_error(png_ptr, "Missing PLTE before IDAT");

      png_ptr->mode |= PNG_HAVE_IDAT;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;

-      if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+      if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
         if (png_ptr->push_length == 0)
            return;

-      if (png_ptr->mode & PNG_AFTER_IDAT)
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_benign_error(png_ptr, "Too many IDATs found");
   }

@@ -249,23 +251,13 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
      if (png_ptr->push_length != 13)
         png_error(png_ptr, "Invalid IHDR length");

-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IEND)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
@@ -275,12 +267,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);

      if (chunk_name == png_PLTE)
@@ -290,11 +277,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   else if (chunk_name == png_PLTE)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -313,12 +296,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_gAMA_SUPPORTED
   else if (png_ptr->chunk_name == png_gAMA)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -326,12 +304,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sBIT_SUPPORTED
   else if (png_ptr->chunk_name == png_sBIT)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -339,12 +312,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_cHRM_SUPPORTED
   else if (png_ptr->chunk_name == png_cHRM)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -352,12 +320,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sRGB_SUPPORTED
   else if (chunk_name == png_sRGB)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -365,12 +328,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iCCP_SUPPORTED
   else if (png_ptr->chunk_name == png_iCCP)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -378,12 +336,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sPLT_SUPPORTED
   else if (chunk_name == png_sPLT)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -391,12 +344,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tRNS_SUPPORTED
   else if (chunk_name == png_tRNS)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -404,12 +352,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_bKGD_SUPPORTED
   else if (chunk_name == png_bKGD)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -417,12 +360,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_hIST_SUPPORTED
   else if (chunk_name == png_hIST)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -430,12 +368,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pHYs_SUPPORTED
   else if (chunk_name == png_pHYs)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -443,12 +376,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_oFFs_SUPPORTED
   else if (chunk_name == png_oFFs)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif
@@ -456,12 +384,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pCAL_SUPPORTED
   else if (chunk_name == png_pCAL)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -469,12 +392,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sCAL_SUPPORTED
   else if (chunk_name == png_sCAL)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -482,12 +400,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tIME_SUPPORTED
   else if (chunk_name == png_tIME)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -495,12 +408,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tEXt_SUPPORTED
   else if (chunk_name == png_tEXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -508,12 +416,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_zTXt_SUPPORTED
   else if (chunk_name == png_zTXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -521,23 +424,14 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iTXt_SUPPORTED
   else if (chunk_name == png_iTXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif

   else
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
         PNG_HANDLE_CHUNK_AS_DEFAULT);
   }
@@ -555,7 +449,7 @@ png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
 void /* PRIVATE */
 png_push_crc_finish(png_structrp png_ptr)
 {
-   if (png_ptr->skip_length && png_ptr->save_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -579,7 +473,7 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (png_ptr->skip_length && png_ptr->current_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -600,14 +494,9 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (!png_ptr->skip_length)
+   if (png_ptr->skip_length == 0)
   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
   }
@@ -622,7 +511,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      return;

   ptr = buffer;
-   if (png_ptr->save_buffer_size)
+   if (png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size;

@@ -639,7 +528,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (length && png_ptr->current_buffer_size)
+   if (length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size;

@@ -659,7 +548,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 void /* PRIVATE */
 png_push_save_buffer(png_structrp png_ptr)
 {
-   if (png_ptr->save_buffer_size)
+   if (png_ptr->save_buffer_size != 0)
   {
      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
      {
@@ -695,11 +584,13 @@ png_push_save_buffer(png_structrp png_ptr)
      if (png_ptr->save_buffer == NULL)
      {
         png_free(png_ptr, old_buffer);
+         old_buffer = NULL;
         png_error(png_ptr, "Insufficient memory for save_buffer");
      }

      memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
      png_free(png_ptr, old_buffer);
+      old_buffer = NULL;
      png_ptr->save_buffer_max = new_max;
   }
   if (png_ptr->current_buffer_size)
@@ -726,18 +617,13 @@ png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
 void /* PRIVATE */
 png_push_read_IDAT(png_structrp png_ptr)
 {
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      /* TODO: this code can be commoned up with the same code in push_read */
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -749,7 +635,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;

-         if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
            png_error(png_ptr, "Not enough compressed data");

         return;
@@ -758,7 +644,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->idat_size = png_ptr->push_length;
   }

-   if (png_ptr->idat_size && png_ptr->save_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -785,7 +671,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->save_buffer_ptr += save_size;
   }

-   if (png_ptr->idat_size && png_ptr->current_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -810,14 +696,9 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (!png_ptr->idat_size)
+   if (png_ptr->idat_size == 0)
   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
      png_ptr->mode |= PNG_AFTER_IDAT;
@@ -962,7 +843,7 @@ png_push_process_row(png_structrp png_ptr)
   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);

 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations)
+   if (png_ptr->transformations != 0)
      png_do_read_transformations(png_ptr, &row_info);
 #endif

@@ -980,7 +861,8 @@ png_push_process_row(png_structrp png_ptr)

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -1187,7 +1069,7 @@ png_read_push_finish_row(png_structrp png_ptr)
   if (png_ptr->row_number < png_ptr->num_rows)
      return;

-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
@@ -1211,7 +1093,7 @@ png_read_push_finish_row(png_structrp png_ptr)
             png_pass_start[png_ptr->pass]) /
             png_pass_inc[png_ptr->pass];

-         if (png_ptr->transformations & PNG_INTERLACE)
+         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
            break;

         png_ptr->num_rows = (png_ptr->height +
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1090,7 +1090,7 @@ PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,

 #ifdef PNG_WRITE_zTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
-    key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY);
+    key, png_const_charp text, int compression),PNG_EMPTY);
 #endif

 #ifdef PNG_WRITE_iTXt_SUPPORTED
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -113,20 +113,20 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
       */
      if (chunk_name == png_IDAT)
      {
-         if (!(png_ptr->mode & PNG_HAVE_IHDR))
+         if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
            png_chunk_error(png_ptr, "Missing IHDR before IDAT");

         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-             !(png_ptr->mode & PNG_HAVE_PLTE))
+             (png_ptr->mode & PNG_HAVE_PLTE) == 0)
            png_chunk_error(png_ptr, "Missing PLTE before IDAT");

-         else if (png_ptr->mode & PNG_AFTER_IDAT)
+         else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
            png_chunk_benign_error(png_ptr, "Too many IDATs found");

         png_ptr->mode |= PNG_HAVE_IDAT;
      }

-      else if (png_ptr->mode & PNG_HAVE_IDAT)
+      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
         png_ptr->mode |= PNG_AFTER_IDAT;

      /* This should be a binary subdivision search or a hash for
@@ -315,7 +315,7 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
   png_debug(1, "in png_do_read_intrapixel");

   if (
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -385,7 +385,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   /* png_read_start_row sets the information (in particular iwidth) for this
    * interlace pass.
    */
-   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
      png_read_start_row(png_ptr);

   /* 1.5.6: row_info moved out of png_struct to a local here. */
@@ -396,45 +396,47 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   row_info.pixel_depth = png_ptr->pixel_depth;
   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);

+#ifdef PNG_WARNINGS_SUPPORTED
   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
   {
   /* Check for transforms that have been set but were defined out */
 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
    !defined(PNG_READ_PACKSWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
 #endif
   }
+#endif /* PNG_WARNINGS_SUPPORTED */

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* If interlaced and we do not need a new row, combine row and return.
@@ -443,7 +445,8 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
    * untransformed) and, because of the libpng API for interlaced images, this
    * means we must transform before de-interlacing.
    */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      switch (png_ptr->pass)
      {
@@ -514,7 +517,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)

         default:
         case 6:
-            if (!(png_ptr->row_number & 1))
+            if ((png_ptr->row_number & 1) == 0)
            {
               png_read_finish_row(png_ptr);
               return;
@@ -524,7 +527,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   }
 #endif

-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
      png_error(png_ptr, "Invalid attempt to read row data");

   /* Fill the row with IDAT data: */
@@ -547,7 +550,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -573,8 +576,8 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced &&
-      (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+      (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -697,7 +700,7 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
      return;

 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
   {
      pass = png_set_interlace_handling(png_ptr);
      /* And make sure transforms are initialized. */
@@ -705,7 +708,8 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
   }
   else
   {
-      if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
+      if (png_ptr->interlaced != 0 &&
+          (png_ptr->transformations & PNG_INTERLACE) == 0)
      {
         /* Caller called png_start_read_image or png_read_update_info without
          * first turning on the PNG_INTERLACE transform.  We can fix this here,
@@ -765,7 +769,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
    * still be pending IDAT data and an owned zstream.  Deal with this here.
    */
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   if (!png_chunk_unknown_handling(png_ptr, png_IDAT))
+   if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
 #endif
      png_read_finish_IDAT(png_ptr);

@@ -795,7 +799,8 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      {
         if (chunk_name == png_IDAT)
         {
-            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+            if ((length > 0) ||
+                (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
               png_benign_error(png_ptr, "Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length, keep);
@@ -809,7 +814,8 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
         /* Zero length IDATs are legal after the last IDAT has been
          * read, but not after other chunks have been read.
          */
-         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+         if ((length > 0) ||
+             (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
            png_benign_error(png_ptr, "Too many IDATs found");

         png_crc_finish(png_ptr, length);
@@ -905,7 +911,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      else
         png_handle_unknown(png_ptr, info_ptr, length,
            PNG_HANDLE_CHUNK_AS_DEFAULT);
-   } while (!(png_ptr->mode & PNG_HAVE_IEND));
+   } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
 }
 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

@@ -920,22 +926,33 @@ png_read_destroy(png_structrp png_ptr)
 #endif

   png_free(png_ptr, png_ptr->big_row_buf);
+   png_ptr->big_row_buf = NULL;
   png_free(png_ptr, png_ptr->big_prev_row);
+   png_ptr->big_prev_row = NULL;
   png_free(png_ptr, png_ptr->read_buffer);
+   png_ptr->read_buffer = NULL;

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
   png_free(png_ptr, png_ptr->palette_lookup);
+   png_ptr->palette_lookup = NULL;
   png_free(png_ptr, png_ptr->quantize_index);
+   png_ptr->quantize_index = NULL;
 #endif

-   if (png_ptr->free_me & PNG_FREE_PLTE)
+   if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
+   {
      png_zfree(png_ptr, png_ptr->palette);
+      png_ptr->palette = NULL;
+   }
   png_ptr->free_me &= ~PNG_FREE_PLTE;

 #if defined(PNG_tRNS_SUPPORTED) || \
    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   if (png_ptr->free_me & PNG_FREE_TRNS)
+   if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
+   {
      png_free(png_ptr, png_ptr->trans_alpha);
+      png_ptr->trans_alpha = NULL;
+   }
   png_ptr->free_me &= ~PNG_FREE_TRNS;
 #endif

@@ -943,15 +960,18 @@ png_read_destroy(png_structrp png_ptr)

 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   png_free(png_ptr, png_ptr->save_buffer);
+   png_ptr->save_buffer = NULL;
 #endif

 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
   defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
   png_free(png_ptr, png_ptr->unknown_chunk.data);
+   png_ptr->unknown_chunk.data = NULL;
 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
 #endif

   /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
@@ -1023,7 +1043,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
    */
-   if (transforms & PNG_TRANSFORM_SCALE_16)
+   if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
     /* Added at libpng-1.5.4. "strip_16" produces the same result that it
      * did in earlier versions, while "scale_16" is now more accurate.
      */
@@ -1037,7 +1057,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * latter by doing SCALE first.  This is ok and allows apps not to check for
    * which is supported to get the right answer.
    */
-   if (transforms & PNG_TRANSFORM_STRIP_16)
+   if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
      png_set_strip_16(png_ptr);
 #else
@@ -1047,7 +1067,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Strip alpha bytes from the input data without combining with
    * the background (not recommended).
    */
-   if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
+   if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
      png_set_strip_alpha(png_ptr);
 #else
@@ -1057,7 +1077,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
    * byte into separate bytes (useful for paletted and grayscale images).
    */
-   if (transforms & PNG_TRANSFORM_PACKING)
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
 #ifdef PNG_READ_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1067,7 +1087,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Change the order of packed pixels to least significant bit first
    * (not useful if you are using png_set_packing).
    */
-   if (transforms & PNG_TRANSFORM_PACKSWAP)
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
 #ifdef PNG_READ_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1079,7 +1099,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * Expand paletted or RGB images with transparency to full alpha
    * channels so the data will be available as RGBA quartets.
    */
-   if (transforms & PNG_TRANSFORM_EXPAND)
+   if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
 #ifdef PNG_READ_EXPAND_SUPPORTED
      png_set_expand(png_ptr);
 #else
@@ -1091,7 +1111,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

   /* Invert monochrome files to have 0 as white and 1 as black
    */
-   if (transforms & PNG_TRANSFORM_INVERT_MONO)
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
 #ifdef PNG_READ_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1102,16 +1122,16 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if (transforms & PNG_TRANSFORM_SHIFT)
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
 #ifdef PNG_READ_SHIFT_SUPPORTED
-      if (info_ptr->valid & PNG_INFO_sBIT)
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
         png_set_shift(png_ptr, &info_ptr->sig_bit);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
 #endif

   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if (transforms & PNG_TRANSFORM_BGR)
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
 #ifdef PNG_READ_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1119,7 +1139,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
-   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1127,7 +1147,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bytes of 16-bit files to least significant byte first */
-   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
 #ifdef PNG_READ_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1136,7 +1156,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

 /* Added at libpng-1.2.41 */
   /* Invert the alpha channel from opacity to transparency */
-   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1145,7 +1165,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

 /* Added at libpng-1.2.41 */
   /* Expand grayscale image to RGB */
-   if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
+   if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
      png_set_gray_to_rgb(png_ptr);
 #else
@@ -1153,7 +1173,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

 /* Added at libpng-1.5.4 */
-   if (transforms & PNG_TRANSFORM_EXPAND_16)
+   if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
 #ifdef PNG_READ_EXPAND_16_SUPPORTED
      png_set_expand_16(png_ptr);
 #else
@@ -1311,10 +1331,10 @@ png_image_format(png_structrp png_ptr)
 {
   png_uint_32 format = 0;

-   if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      format |= PNG_FORMAT_FLAG_COLOR;

-   if (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      format |= PNG_FORMAT_FLAG_ALPHA;

   /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
@@ -1328,7 +1348,7 @@ png_image_format(png_structrp png_ptr)
   if (png_ptr->bit_depth == 16)
      format |= PNG_FORMAT_FLAG_LINEAR;

-   if (png_ptr->color_type & PNG_COLOR_MASK_PALETTE)
+   if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
      format |= PNG_FORMAT_FLAG_COLORMAP;

   return format;
@@ -1428,7 +1448,7 @@ png_image_begin_read_from_stdio(png_imagep image, FILE* file)
   {
      if (file != NULL)
      {
-         if (png_image_read_init(image))
+         if (png_image_read_init(image) != 0)
         {
            /* This is slightly evil, but png_init_io doesn't do anything other
             * than this and we haven't changed the standard IO functions so
@@ -1462,7 +1482,7 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)

         if (fp != NULL)
         {
-            if (png_image_read_init(image))
+            if (png_image_read_init(image) != 0)
            {
               image->opaque->png_ptr->io_ptr = fp;
               image->opaque->owned_file = 1;
@@ -1527,7 +1547,7 @@ int PNGAPI png_image_begin_read_from_memory(png_imagep image,
   {
      if (memory != NULL && size > 0)
      {
-         if (png_image_read_init(image))
+         if (png_image_read_init(image) != 0)
         {
            /* Now set the IO functions to read from the memory buffer and
             * store it into io_ptr.  Again do this in-place to avoid calling a
@@ -1619,9 +1639,9 @@ static void
 set_file_encoding(png_image_read_control *display)
 {
   png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
-   if (png_gamma_significant(g))
+   if (png_gamma_significant(g) != 0)
   {
-      if (png_gamma_not_sRGB(g))
+      if (png_gamma_not_sRGB(g) != 0)
      {
         display->file_encoding = P_FILE;
         display->gamma_to_linear = png_reciprocal(g);
@@ -1716,7 +1736,7 @@ png_create_colormap_entry(png_image_read_control *display,
   png_uint_32 alpha, int encoding)
 {
   png_imagep image = display->image;
-   const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) ?
+   const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
      P_LINEAR : P_sRGB;
   const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
      (red != green || green != blue);
@@ -1746,7 +1766,7 @@ png_create_colormap_entry(png_image_read_control *display,
      green = png_gamma_16bit_correct(green*257, g);
      blue = png_gamma_16bit_correct(blue*257, g);

-      if (convert_to_Y || output_encoding == P_LINEAR)
+      if (convert_to_Y != 0 || output_encoding == P_LINEAR)
      {
         alpha *= 257;
         encoding = P_LINEAR;
@@ -1773,7 +1793,8 @@ png_create_colormap_entry(png_image_read_control *display,
      encoding = P_LINEAR;
   }

-   else if (encoding == P_sRGB && (convert_to_Y || output_encoding == P_LINEAR))
+   else if (encoding == P_sRGB &&
+       (convert_to_Y  != 0 || output_encoding == P_LINEAR))
   {
      /* The values are 8-bit sRGB values, but must be converted to 16-bit
       * linear.
@@ -1831,7 +1852,7 @@ png_create_colormap_entry(png_image_read_control *display,
 #        define afirst 0
 #     endif
 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
+         const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
 #     else
 #        define bgr 0
 #     endif
@@ -2043,7 +2064,7 @@ png_image_read_colormap(png_voidp argument)

   const png_structrp png_ptr = image->opaque->png_ptr;
   const png_uint_32 output_format = image->format;
-   const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) ?
+   const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
      P_LINEAR : P_sRGB;

   unsigned int cmap_entries;
@@ -2082,7 +2103,7 @@ png_image_read_colormap(png_voidp argument)
      else
      {
         back_g = display->background->green;
-         if (output_format & PNG_FORMAT_FLAG_COLOR)
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
         {
            back_r = display->background->red;
            back_b = display->background->blue;
@@ -2224,7 +2245,7 @@ png_image_read_colormap(png_voidp argument)
            {
               unsigned int back_alpha;

-               if (output_format & PNG_FORMAT_FLAG_ALPHA)
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
                  back_alpha = 0;

               else
@@ -2305,7 +2326,7 @@ png_image_read_colormap(png_voidp argument)
          */
         data_encoding = P_sRGB;

-         if (output_format & PNG_FORMAT_FLAG_ALPHA)
+         if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
         {
            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
               png_error(png_ptr, "gray+alpha color-map: too few entries");
@@ -2500,7 +2521,7 @@ png_image_read_colormap(png_voidp argument)
                */
               if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
                  png_ptr->num_trans > 0) &&
-                  png_gamma_not_sRGB(png_ptr->colorspace.gamma))
+                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
               {
                  cmap_entries = make_gray_file_colormap(display);
                  data_encoding = P_FILE;
@@ -2588,7 +2609,7 @@ png_image_read_colormap(png_voidp argument)
               /* Is there alpha in the output too?  If so all four channels are
                * processed into a special RGB cube with alpha support.
                */
-               if (output_format & PNG_FORMAT_FLAG_ALPHA)
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
               {
                  png_uint_32 r;

@@ -2762,7 +2783,7 @@ png_image_read_colormap(png_voidp argument)

            for (i=0; i < cmap_entries; ++i)
            {
-               if (do_background && i < num_trans && trans[i] < 255)
+               if (do_background != 0 && i < num_trans && trans[i] < 255)
               {
                  if (trans[i] == 0)
                     png_create_colormap_entry(display, i, back_r, back_g,
@@ -2807,8 +2828,8 @@ png_image_read_colormap(png_voidp argument)
   }

   /* Now deal with the output processing */
-   if (expand_tRNS && png_ptr->num_trans > 0 &&
-      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
+   if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
      png_set_tRNS_to_alpha(png_ptr);

   switch (data_encoding)
@@ -3224,7 +3245,8 @@ png_image_read_composite(png_voidp argument)
      png_uint_32  height = image->height;
      png_uint_32  width = image->width;
      ptrdiff_t    step_row = display->row_bytes;
-      unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+      unsigned int channels =
+         (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
      int pass;

      for (pass = 0; pass < passes; ++pass)
@@ -3522,7 +3544,8 @@ png_image_read_background(png_voidp argument)
            int swap_alpha = 0;

 #           ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
-               if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST))
+               if (preserve_alpha != 0 &&
+                   (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
                  swap_alpha = 1;
 #           endif

@@ -3631,10 +3654,10 @@ png_image_read_direct(png_voidp argument)
      int mode; /* alpha mode */

      /* Do this first so that we have a record if rgb to gray is happening. */
-      if (change & PNG_FORMAT_FLAG_COLOR)
+      if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
      {
         /* gray<->color transformation required. */
-         if (format & PNG_FORMAT_FLAG_COLOR)
+         if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_gray_to_rgb(png_ptr);

         else
@@ -3652,7 +3675,7 @@ png_image_read_direct(png_voidp argument)
             * enormous change) 'do_local_background' is used to indicate that
             * the problem exists.
             */
-            if (base_format & PNG_FORMAT_FLAG_ALPHA)
+            if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
               do_local_background = 1/*maybe*/;

            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
@@ -3667,8 +3690,8 @@ png_image_read_direct(png_voidp argument)
      {
         png_fixed_point input_gamma_default;

-         if ((base_format & PNG_FORMAT_FLAG_LINEAR) &&
-            (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+         if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+             (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
            input_gamma_default = PNG_GAMMA_LINEAR;
         else
            input_gamma_default = PNG_DEFAULT_sRGB;
@@ -3684,7 +3707,7 @@ png_image_read_direct(png_voidp argument)
         /* If there *is* an alpha channel in the input it must be multiplied
          * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
          */
-         if (base_format & PNG_FORMAT_FLAG_ALPHA)
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
            mode = PNG_ALPHA_STANDARD; /* associated alpha */

         else
@@ -3715,7 +3738,7 @@ png_image_read_direct(png_voidp argument)
          * final value.
          */
         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
-               PNG_FP_1) && !png_gamma_significant(gtest))
+               PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
            do_local_background = 0;

         else if (mode == PNG_ALPHA_STANDARD)
@@ -3728,9 +3751,9 @@ png_image_read_direct(png_voidp argument)
      }

      /* If the bit-depth changes then handle that here. */
-      if (change & PNG_FORMAT_FLAG_LINEAR)
+      if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
      {
-         if (linear /*16-bit output*/)
+         if (linear != 0 /*16-bit output*/)
            png_set_expand_16(png_ptr);

         else /* 8-bit output */
@@ -3740,13 +3763,13 @@ png_image_read_direct(png_voidp argument)
      }

      /* Now the background/alpha channel changes. */
-      if (change & PNG_FORMAT_FLAG_ALPHA)
+      if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
      {
         /* Removing an alpha channel requires composition for the 8-bit
          * formats; for the 16-bit it is already done, above, by the
          * pre-multiplication and the channel just needs to be stripped.
          */
-         if (base_format & PNG_FORMAT_FLAG_ALPHA)
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
         {
            /* If RGB->gray is happening the alpha channel must be left and the
             * operation completed locally.
@@ -3811,7 +3834,7 @@ png_image_read_direct(png_voidp argument)
               filler = 255;

 #           ifdef PNG_FORMAT_AFIRST_SUPPORTED
-               if (format & PNG_FORMAT_FLAG_AFIRST)
+               if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
               {
                  where = PNG_FILLER_BEFORE;
                  change &= ~PNG_FORMAT_FLAG_AFIRST;
@@ -3835,12 +3858,12 @@ png_image_read_direct(png_voidp argument)
      png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);

 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         if (change & PNG_FORMAT_FLAG_BGR)
+         if ((change & PNG_FORMAT_FLAG_BGR) != 0)
         {
            /* Check only the output format; PNG is never BGR; don't do this if
             * the output is gray, but fix up the 'format' value in that case.
             */
-            if (format & PNG_FORMAT_FLAG_COLOR)
+            if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
               png_set_bgr(png_ptr);

            else
@@ -3851,14 +3874,14 @@ png_image_read_direct(png_voidp argument)
 #     endif

 #     ifdef PNG_FORMAT_AFIRST_SUPPORTED
-         if (change & PNG_FORMAT_FLAG_AFIRST)
+         if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            /* Only relevant if there is an alpha channel - it's particularly
             * important to handle this correctly because do_local_compose may
             * be set above and then libpng will keep the alpha channel for this
             * code to remove.
             */
-            if (format & PNG_FORMAT_FLAG_ALPHA)
+            if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
            {
               /* Disable this if doing a local background,
                * TODO: remove this when local background is no longer required.
@@ -3881,7 +3904,7 @@ png_image_read_direct(png_voidp argument)
      {
         PNG_CONST png_uint_16 le = 0x0001;

-         if (*(png_const_bytep)&le)
+         if ((*(png_const_bytep) & le) != 0)
            png_set_swap(png_ptr);
      }

@@ -3906,10 +3929,10 @@ png_image_read_direct(png_voidp argument)
   {
      png_uint_32 info_format = 0;

-      if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+      if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
         info_format |= PNG_FORMAT_FLAG_COLOR;

-      if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+      if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         /* do_local_compose removes this channel below. */
         if (do_local_compose == 0)
@@ -3928,14 +3951,14 @@ png_image_read_direct(png_voidp argument)
         info_format |= PNG_FORMAT_FLAG_LINEAR;

 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         if (png_ptr->transformations & PNG_BGR)
+         if ((png_ptr->transformations & PNG_BGR) != 0)
            info_format |= PNG_FORMAT_FLAG_BGR;
 #     endif

 #     ifdef PNG_FORMAT_AFIRST_SUPPORTED
         if (do_local_background == 2)
         {
-            if (format & PNG_FORMAT_FLAG_AFIRST)
+            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
               info_format |= PNG_FORMAT_FLAG_AFIRST;
         }

@@ -4064,7 +4087,7 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
            /* Choose the correct 'end' routine; for the color-map case all the
             * setup has already been done.
             */
-            if (image->format & PNG_FORMAT_FLAG_COLORMAP)
+            if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
               result =
                  png_safe_execute(image, png_image_read_colormap, &display) &&
                  png_safe_execute(image, png_image_read_colormapped, &display);
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@

 /* pngrtran.c - transforms the data in a row for PNG readers
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -98,7 +98,7 @@ png_rtran_ok(png_structrp png_ptr, int need_IHDR)
 {
   if (png_ptr != NULL)
   {
-      if (png_ptr->flags & PNG_FLAG_ROW_INIT)
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
         png_app_error(png_ptr,
            "invalid after png_start_read_image or png_read_update_info");

@@ -127,7 +127,7 @@ png_set_background_fixed(png_structrp png_ptr,
 {
   png_debug(1, "in png_set_background_fixed");

-   if (!png_rtran_ok(png_ptr, 0) || background_color == NULL)
+   if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
      return;

   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
@@ -171,7 +171,7 @@ png_set_scale_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_scale_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_SCALE_16_TO_8;
@@ -185,7 +185,7 @@ png_set_strip_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_strip_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_16_TO_8;
@@ -198,7 +198,7 @@ png_set_strip_alpha(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_strip_alpha");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_STRIP_ALPHA;
@@ -279,7 +279,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,

   png_debug(1, "in png_set_alpha_mode");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
@@ -371,7 +371,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
      png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;

-      if (png_ptr->transformations & PNG_COMPOSE)
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
         png_error(png_ptr,
            "conflicting calls to set alpha mode and background");

@@ -415,7 +415,7 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,
 {
   png_debug(1, "in png_set_quantize");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_QUANTIZE;
@@ -802,7 +802,7 @@ png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
 {
   png_debug(1, "in png_set_gamma_fixed");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   /* New in libpng-1.5.4 - reserve particular negative values as flags. */
@@ -855,7 +855,7 @@ png_set_expand(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -885,7 +885,7 @@ png_set_palette_to_rgb(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_palette_to_rgb");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -897,7 +897,7 @@ png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_EXPAND;
@@ -909,7 +909,7 @@ png_set_tRNS_to_alpha(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_tRNS_to_alpha");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -925,7 +925,7 @@ png_set_expand_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -938,7 +938,7 @@ png_set_gray_to_rgb(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_gray_to_rgb");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   /* Because rgb must be 8 bits or more: */
@@ -956,10 +956,10 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,

   /* Need the IHDR here because of the check on color_type below. */
   /* TODO: fix this */
-   if (!png_rtran_ok(png_ptr, 1))
+   if (png_rtran_ok(png_ptr, 1) == 0)
      return;

-   switch(error_action)
+   switch (error_action)
   {
      case PNG_ERROR_ACTION_NONE:
         png_ptr->transformations |= PNG_RGB_TO_GRAY;
@@ -1153,8 +1153,8 @@ png_init_palette_transformations(png_structrp png_ptr)
   /* The following code cannot be entered in the alpha pre-multiplication case
    * because PNG_BACKGROUND_EXPAND is cancelled below.
    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND))
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0)
   {
      {
         png_ptr->background.red   =
@@ -1165,9 +1165,9 @@ png_init_palette_transformations(png_structrp png_ptr)
             png_ptr->palette[png_ptr->background.index].blue;

 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-        if (png_ptr->transformations & PNG_INVERT_ALPHA)
+        if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
        {
-           if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+           if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
           {
              /* Invert the alpha channel (in tRNS) unless the pixels are
               * going to be expanded, in which case leave it for later
@@ -1220,9 +1220,9 @@ png_init_rgb_transformations(png_structrp png_ptr)
   /* The following code cannot be entered in the alpha pre-multiplication case
    * because PNG_BACKGROUND_EXPAND is cancelled below.
    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND) &&
-       !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
       /* i.e., GRAY or GRAY_ALPHA */
   {
      {
@@ -1260,7 +1260,7 @@ png_init_rgb_transformations(png_structrp png_ptr)
         png_ptr->background.red = png_ptr->background.green =
            png_ptr->background.blue = (png_uint_16)gray;

-         if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+         if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
         {
            png_ptr->trans_color.red = png_ptr->trans_color.green =
               png_ptr->trans_color.blue = (png_uint_16)trans_gray;
@@ -1374,8 +1374,8 @@ png_init_read_transformations(png_structrp png_ptr)
    * 23) PNG_USER_TRANSFORM [must be last]
    */
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0)
   {
      /* Stripping the alpha channel happens immediately after the 'expand'
       * transformations, before all other transformation, so it cancels out
@@ -1401,7 +1401,7 @@ png_init_read_transformations(png_structrp png_ptr)
   /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
    * settings will have no effect.
    */
-   if (!png_gamma_significant(png_ptr->screen_gamma))
+   if (png_gamma_significant(png_ptr->screen_gamma) == 0)
   {
      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
@@ -1412,7 +1412,7 @@ png_init_read_transformations(png_structrp png_ptr)
   /* Make sure the coefficients for the rgb to gray conversion are set
    * appropriately.
    */
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
      png_colorspace_set_rgb_coefficients(png_ptr);
 #endif

@@ -1433,23 +1433,23 @@ png_init_read_transformations(png_structrp png_ptr)
    * png_set_background, along with the bit depth, then the code has a record
    * of exactly what color space the background is currently in.
    */
-   if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
   {
      /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
       * the file was grayscale the background value is gray.
       */
-      if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
         png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
   }

-   else if (png_ptr->transformations & PNG_COMPOSE)
+   else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
   {
      /* PNG_COMPOSE: png_set_background was called with need_expand false,
       * so the color is in the color space of the output or png_set_alpha_mode
       * was called and the color is black.  Ignore RGB_TO_GRAY because that
       * happens before GRAY_TO_RGB.
       */
-      if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+      if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
      {
         if (png_ptr->background.red == png_ptr->background.green &&
             png_ptr->background.red == png_ptr->background.blue)
@@ -1481,10 +1481,10 @@ png_init_read_transformations(png_structrp png_ptr)

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
   defined(PNG_READ_EXPAND_16_SUPPORTED)
-   if ((png_ptr->transformations & PNG_EXPAND_16) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth != 16)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth != 16)
   {
      /* TODO: fix this.  Because the expand_16 operation is after the compose
       * handling the background color must be 8, not 16, bits deep, but the
@@ -1508,10 +1508,10 @@ png_init_read_transformations(png_structrp png_ptr)
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
   (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
   defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
-   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth == 16)
+   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth == 16)
   {
      /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
       * component this will also happen after PNG_COMPOSE and so the background
@@ -1554,25 +1554,24 @@ png_init_read_transformations(png_structrp png_ptr)
    * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
    * tables.
    */
-   if ((png_ptr->transformations & PNG_GAMMA)
-      || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
-         && (png_gamma_significant(png_ptr->colorspace.gamma) ||
-            png_gamma_significant(png_ptr->screen_gamma)))
-      || ((png_ptr->transformations & PNG_COMPOSE)
-         && (png_gamma_significant(png_ptr->colorspace.gamma)
-            || png_gamma_significant(png_ptr->screen_gamma)
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
+       ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
+        (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+         png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
+        ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+         (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+          png_gamma_significant(png_ptr->screen_gamma) != 0
 #  ifdef PNG_READ_BACKGROUND_SUPPORTED
-            || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
-               && png_gamma_significant(png_ptr->background_gamma))
+         || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
+           png_gamma_significant(png_ptr->background_gamma) != 0)
 #  endif
-      )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
-         && png_gamma_significant(png_ptr->screen_gamma))
-      )
+        )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       png_gamma_significant(png_ptr->screen_gamma) != 0))
   {
      png_build_gamma_table(png_ptr, png_ptr->bit_depth);

 #ifdef PNG_READ_BACKGROUND_SUPPORTED
-      if (png_ptr->transformations & PNG_COMPOSE)
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      {
         /* Issue a warning about this combination: because RGB_TO_GRAY is
          * optimized to do the gamma transform if present yet do_background has
@@ -1580,11 +1579,11 @@ png_init_read_transformations(png_structrp png_ptr)
          * double-gamma-correction happens.  This is true in all versions of
          * libpng to date.
          */
-         if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
            png_warning(png_ptr,
               "libpng does not support gamma+background+rgb_to_gray");

-         if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
         {
            /* We don't get to here unless there is a tRNS chunk with non-opaque
             * entries - see the checking code at the start of this function.
@@ -1632,7 +1631,7 @@ png_init_read_transformations(png_structrp png_ptr)
                     break;
               }

-               if (png_gamma_significant(gs))
+               if (png_gamma_significant(gs) != 0)
               {
                  back.red = png_gamma_8bit_correct(png_ptr->background.red,
                      gs);
@@ -1649,7 +1648,7 @@ png_init_read_transformations(png_structrp png_ptr)
                  back.blue  = (png_byte)png_ptr->background.blue;
               }

-               if (png_gamma_significant(g))
+               if (png_gamma_significant(g) != 0)
               {
                  back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
                     g);
@@ -1832,7 +1831,7 @@ png_init_read_transformations(png_structrp png_ptr)

 #ifdef PNG_READ_BACKGROUND_SUPPORTED
   /* No GAMMA transformation (see the hanging else 4 lines above) */
-   if ((png_ptr->transformations & PNG_COMPOSE) &&
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
   {
      int i;
@@ -1870,8 +1869,8 @@ png_init_read_transformations(png_structrp png_ptr)
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */

 #ifdef PNG_READ_SHIFT_SUPPORTED
-   if ((png_ptr->transformations & PNG_SHIFT) &&
-      !(png_ptr->transformations & PNG_EXPAND) &&
+   if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) == 0 &&
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
   {
      int i;
@@ -1926,7 +1925,7 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   png_debug(1, "in png_read_transform_info");

 #ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
   {
      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
@@ -1948,9 +1947,9 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
      }
      else
      {
-         if (png_ptr->num_trans)
+         if (png_ptr->num_trans != 0)
         {
-            if (png_ptr->transformations & PNG_EXPAND_tRNS)
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
         }
         if (info_ptr->bit_depth < 8)
@@ -1966,7 +1965,7 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   /* The following is almost certainly wrong unless the background value is in
    * the screen space!
    */
-   if (png_ptr->transformations & PNG_COMPOSE)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      info_ptr->background = png_ptr->background;
 #endif

@@ -1987,12 +1986,12 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   {
 #  ifdef PNG_READ_16BIT_SUPPORTED
 #     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+         if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
            info_ptr->bit_depth = 8;
 #     endif

 #     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_16_TO_8)
+         if ((png_ptr->transformations & PNG_16_TO_8) != 0)
            info_ptr->bit_depth = 8;
 #     endif

@@ -2022,23 +2021,23 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   }

 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
      info_ptr->color_type = (png_byte)(info_ptr->color_type |
         PNG_COLOR_MASK_COLOR);
 #endif

 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
      info_ptr->color_type = (png_byte)(info_ptr->color_type &
         ~PNG_COLOR_MASK_COLOR);
 #endif

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
   {
      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-          png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+          png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
      {
         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
      }
@@ -2046,29 +2045,31 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 #endif

 #ifdef PNG_READ_EXPAND_16_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
-      info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       info_ptr->bit_depth == 8 &&
+       info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
   {
      info_ptr->bit_depth = 16;
   }
 #endif

 #ifdef PNG_READ_PACK_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
+   if ((png_ptr->transformations & PNG_PACK) != 0 &&
+       (info_ptr->bit_depth < 8))
      info_ptr->bit_depth = 8;
 #endif

   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

-   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_STRIP_ALPHA)
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
   {
      info_ptr->color_type = (png_byte)(info_ptr->color_type &
         ~PNG_COLOR_MASK_ALPHA);
@@ -2076,25 +2077,25 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   }
 #endif

-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      info_ptr->channels++;

 #ifdef PNG_READ_FILLER_SUPPORTED
   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
-   if ((png_ptr->transformations & PNG_FILLER) &&
-       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
+   if ((png_ptr->transformations & PNG_FILLER) != 0 &&
+       (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+       info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
   {
      info_ptr->channels++;
      /* If adding a true alpha channel not just filler */
-      if (png_ptr->transformations & PNG_ADD_ALPHA)
+      if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
   }
 #endif

 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
   {
      if (info_ptr->bit_depth < png_ptr->user_transform_depth)
         info_ptr->bit_depth = png_ptr->user_transform_depth;
@@ -2245,7 +2246,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
      int channels = 0;
      int bit_depth = row_info->bit_depth;

-      if (color_type & PNG_COLOR_MASK_COLOR)
+      if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
         shift[channels++] = bit_depth - sig_bits->red;
         shift[channels++] = bit_depth - sig_bits->green;
@@ -2257,7 +2258,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
         shift[channels++] = bit_depth - sig_bits->gray;
      }

-      if (color_type & PNG_COLOR_MASK_ALPHA)
+      if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         shift[channels++] = bit_depth - sig_bits->alpha;
      }
@@ -2671,7 +2672,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
   {
      if (row_info->bit_depth == 8)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from G to GX */
            png_bytep sp = row + (png_size_t)row_width;
@@ -2706,7 +2707,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 #ifdef PNG_READ_16BIT_SUPPORTED
      else if (row_info->bit_depth == 16)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from GG to GGXX */
            png_bytep sp = row + (png_size_t)row_width * 2;
@@ -2748,7 +2749,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
   {
      if (row_info->bit_depth == 8)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from RGB to RGBX */
            png_bytep sp = row + (png_size_t)row_width * 3;
@@ -2787,7 +2788,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 #ifdef PNG_READ_16BIT_SUPPORTED
      else if (row_info->bit_depth == 16)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from RRGGBB to RRGGBBXX */
            png_bytep sp = row + (png_size_t)row_width * 6;
@@ -2848,7 +2849,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
   png_debug(1, "in png_do_gray_to_rgb");

   if (row_info->bit_depth >= 8 &&
-       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
@@ -2986,8 +2987,8 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)

   png_debug(1, "in png_do_rgb_to_gray");

-   if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
      PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
@@ -3086,15 +3087,15 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
            {
               png_uint_16 red, green, blue, w;

-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;

               if (red == green && red == blue)
               {
                  if (png_ptr->gamma_16_table != NULL)
-                     w = png_ptr->gamma_16_table[(red&0xff)
-                         >> png_ptr->gamma_shift][red>>8];
+                     w = png_ptr->gamma_16_table[(red & 0xff)
+                         >> png_ptr->gamma_shift][red >> 8];

                  else
                     w = red;
@@ -3137,9 +3138,9 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
            {
               png_uint_16 red, green, blue, gray16;

-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;

               if (red != green || red != blue)
                  rgb_error |= 1;
@@ -3150,7 +3151,7 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
                */
               gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
                  15);
-               *(dp++) = (png_byte)((gray16>>8) & 0xff);
+               *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
               *(dp++) = (png_byte)(gray16 & 0xff);

               if (have_alpha != 0)
@@ -4127,7 +4128,7 @@ png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)

   png_debug(1, "in png_do_encode_alpha");

-   if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
   {
      if (row_info->bit_depth == 8)
      {
@@ -4353,7 +4354,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
-         unsigned int gray = trans_color ? trans_color->gray : 0;
+         unsigned int gray = trans_color != NULL ? trans_color->gray : 0;

         if (row_info->bit_depth < 8)
         {
@@ -4497,7 +4498,8 @@ png_do_expand(png_row_infop row_info, png_bytep row,
               row_width);
         }
      }
-      else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+          trans_color != NULL)
      {
         if (row_info->bit_depth == 8)
         {
@@ -4715,7 +4717,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * demand, if necessary.
    */
   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
-      !(png_ptr->flags & PNG_FLAG_ROW_INIT))
+       (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
   {
      /* Application has failed to call either png_read_start_image() or
       * png_read_update_info() after setting transforms that expand pixels.
@@ -4725,7 +4727,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
   }

 #ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
   {
      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
      {
@@ -4735,8 +4737,8 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)

      else
      {
-         if (png_ptr->num_trans &&
-             (png_ptr->transformations & PNG_EXPAND_tRNS))
+         if (png_ptr->num_trans != 0 &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
            png_do_expand(row_info, png_ptr->row_buf + 1,
                &(png_ptr->trans_color));

@@ -4748,16 +4750,16 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
         0 /* at_start == false, because SWAP_ALPHA happens later */);
 #endif

 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
   {
      int rgb_error =
          png_do_rgb_to_gray(png_ptr, row_info,
@@ -4812,22 +4814,22 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
   /* If gray -> RGB, do so now only if background is non-gray; else do later
    * for performance reasons
    */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
 #endif

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   if (png_ptr->transformations & PNG_COMPOSE)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
 #endif

 #ifdef PNG_READ_GAMMA_SUPPORTED
-   if ((png_ptr->transformations & PNG_GAMMA) &&
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
      /* Because RGB_TO_GRAY does the gamma transform. */
-      !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+      (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
 #endif
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
@@ -4836,7 +4838,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
       */
       !((png_ptr->transformations & PNG_COMPOSE) &&
       ((png_ptr->num_trans != 0) ||
-       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
 #endif
      /* Because png_init_read_transformations transforms the palette, unless
       * RGB_TO_GRAY will do the transform.
@@ -4846,22 +4848,22 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
 #endif

 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
-      (row_info->color_type & PNG_COLOR_MASK_ALPHA))
+   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
 #endif

 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+   if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
 #endif

@@ -4870,12 +4872,12 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * by putting the 'scale' option first if the app asks for scale (either by
    * calling the API or in a TRANSFORM flag) this is what happens.
    */
-   if (png_ptr->transformations & PNG_16_TO_8)
+   if ((png_ptr->transformations & PNG_16_TO_8) != 0)
      png_do_chop(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
   {
      png_do_quantize(row_info, png_ptr->row_buf + 1,
          png_ptr->palette_lookup, png_ptr->quantize_index);
@@ -4891,35 +4893,35 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * is efficient (particularly true in the case of gamma correction, where
    * better accuracy results faster!)
    */
-   if (png_ptr->transformations & PNG_EXPAND_16)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
      png_do_expand_16(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      png_do_unshift(row_info, png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif

 #ifdef PNG_READ_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_do_unpack(row_info, png_ptr->row_buf + 1);
 #endif

@@ -4931,35 +4933,35 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_do_read_filler(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->filler, png_ptr->flags);
 #endif

 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_16BIT_SUPPORTED
 #ifdef PNG_READ_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_do_swap(row_info, png_ptr->row_buf + 1);
 #endif
 #endif

 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
    {
      if (png_ptr->read_user_transform_fn != NULL)
         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
@@ -4973,10 +4975,10 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
             png_ptr->row_buf + 1);    /* start of pixel data for row */
 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-      if (png_ptr->user_transform_depth)
+      if (png_ptr->user_transform_depth != 0)
         row_info->bit_depth = png_ptr->user_transform_depth;

-      if (png_ptr->user_transform_channels)
+      if (png_ptr->user_transform_channels != 0)
         row_info->channels = png_ptr->user_transform_channels;
 #endif
      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
--- a/pngrutil.c
+++ b/pngrutil.c
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -59,7 +59,7 @@ png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   xy.whitey = white_y;

   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
-      2/* override with app values*/))
+       2/* override with app values*/) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -90,7 +90,8 @@ png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   XYZ.blue_Y = int_blue_Y;
   XYZ.blue_Z = int_blue_Z;

-   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace, &XYZ, 2))
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+       &XYZ, 2) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -227,13 +228,13 @@ png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

-   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      info_ptr->channels++;

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
@@ -288,12 +289,14 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,

   /* Validate params[nparams] */
   for (i=0; i<nparams; ++i)
+   {
      if (params[i] == NULL ||
-         !png_check_fp_string(params[i], strlen(params[i])))
+          !png_check_fp_string(params[i], strlen(params[i])))
         png_error(png_ptr, "Invalid format for pCAL parameter");
+   }

   info_ptr->pcal_purpose = png_voidcast(png_charp,
-      png_malloc_warn(png_ptr, length));
+       png_malloc_warn(png_ptr, length));

   if (info_ptr->pcal_purpose == NULL)
   {
@@ -594,7 +597,8 @@ png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent))
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+       srgb_intent) != 0)
   {
      /* This causes the gAMA and cHRM to be written too */
      info_ptr->colorspace.flags |=
@@ -661,6 +665,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
   if (new_iccp_profile == NULL)
   {
      png_free(png_ptr, new_iccp_name);
+      new_iccp_name = NULL;
      png_benign_error(png_ptr,
          "Insufficient memory to process iCCP profile");
      return;
@@ -726,7 +731,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
         else
            max_text = INT_MAX;

-         /* Now allocate a new array and copy the old members in, this does all
+         /* Now allocate a new array and copy the old members in; this does all
          * the overflow checks.
          */
         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
@@ -890,7 +895,7 @@ png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
   png_debug1(1, "in %s storage function", "tIME");

   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
-       (png_ptr->mode & PNG_WROTE_tIME))
+       (png_ptr->mode & PNG_WROTE_tIME) != 0)
      return;

   if (mod_time->month == 0   || mod_time->month > 12  ||
@@ -1020,8 +1025,8 @@ png_set_sPLT(png_const_structrp png_ptr,

      np->depth = entries->depth;

-      /* In the even of out-of-memory just return - there's no point keeping on
-       * trying to add sPLT chunks.
+      /* In the event of out-of-memory just return - there's no point keeping
+       * on trying to add sPLT chunks.
       */
      length = strlen(entries->name) + 1;
      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
@@ -1032,8 +1037,8 @@ png_set_sPLT(png_const_structrp png_ptr,
      memcpy(np->name, entries->name, length);

      /* IMPORTANT: we have memory now that won't get freed if something else
-       * goes wrong, this code must free it.  png_malloc_array produces no
-       * warnings, use a png_chunk_report (below) if there is an error.
+       * goes wrong; this code must free it.  png_malloc_array produces no
+       * warnings; use a png_chunk_report (below) if there is an error.
       */
      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
          entries->nentries, sizeof (png_sPLT_entry)));
@@ -1041,6 +1046,7 @@ png_set_sPLT(png_const_structrp png_ptr,
      if (np->entries == NULL)
      {
         png_free(png_ptr, np->name);
+         np->name = NULL;
         break;
      }

@@ -1072,10 +1078,10 @@ check_location(png_const_structrp png_ptr, int location)
   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);

   /* New in 1.6.0; copy the location and check it.  This is an API
-    * change, previously the app had to use the
+    * change; previously the app had to use the
    * png_set_unknown_chunk_location API below for each chunk.
    */
-   if (location == 0 && !(png_ptr->mode & PNG_IS_READ_STRUCT))
+   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
   {
      /* Write struct, so unknown chunks come from the app */
      png_app_warning(png_ptr,
@@ -1121,7 +1127,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
    */
 #  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_READ_SUPPORTED)
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on read");
         return;
@@ -1129,7 +1135,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
 #  endif
 #  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_WRITE_SUPPORTED)
-      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on write");
         return;
@@ -1215,7 +1221,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      {
         png_app_error(png_ptr, "invalid unknown chunk location");
         /* Fake out the pre 1.6.0 behavior: */
-         if ((location & PNG_HAVE_IDAT)) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
@@ -1253,10 +1259,13 @@ add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
   /* Utility function: update the 'keep' state of a chunk if it is already in
    * the list, otherwise add it to the list.
    */
-   for (i=0; i<count; ++i, list += 5) if (memcmp(list, add, 4) == 0)
+   for (i=0; i<count; ++i, list += 5)
   {
-      list[4] = (png_byte)keep;
-      return count;
+      if (memcmp(list, add, 4) == 0)
+      {
+         list[4] = (png_byte)keep;
+         return count;
+      }
   }

   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
@@ -1380,12 +1389,15 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      unsigned int i;

      for (i=0; i<num_chunks; ++i)
+      {
         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
            chunk_list+5*i, keep);
+      }

      /* Now remove any spurious 'default' entries. */
      num_chunks = 0;
      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
+      {
         if (inlist[4])
         {
            if (outlist != inlist)
@@ -1393,6 +1405,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
            outlist += 5;
            ++num_chunks;
         }
+      }

      /* This means the application has removed all the specialized handling. */
      if (num_chunks == 0)
@@ -1444,7 +1457,8 @@ png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
+   if (info_ptr->row_pointers != NULL &&
+       (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   info_ptr->row_pointers = row_pointers;
@@ -1464,7 +1478,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
       png_error(png_ptr, "invalid compression buffer size");

 #  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
         return;
@@ -1472,7 +1486,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
-      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         if (png_ptr->zowner != 0)
         {
@@ -1510,7 +1524,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 void PNGAPI
 png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
 {
-   if (png_ptr && info_ptr)
+   if (png_ptr != NULL && info_ptr != NULL)
      info_ptr->valid &= ~mask;
 }

@@ -1578,7 +1592,7 @@ png_set_benign_errors(png_structrp png_ptr, int allowed)
    * It is possible for an indexed (color-type==3) PNG file to contain
    * pixels with invalid (out-of-range) indexes if the PLTE chunk has
    * fewer entries than the image's bit-depth would allow. We recover
-    * from this gracefully by filling any incomplete palette with zeroes
+    * from this gracefully by filling any incomplete palette with zeros
    * (opaque black).  By default, when this occurs libpng will issue
    * a benign error.  This API can be used to override that behavior.
    */
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@

 /* pngtest.c - a simple test program to test libpng
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -283,7 +283,8 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       png_uint_32 n, nstop;
       int channel;
       int color_channels = row_info->channels;
-       if (row_info->color_type > 3)color_channels--;
+       if (row_info->color_type > 3)
+          color_channels--;

       for (n = 0, nstop=row_info->width; n<nstop; n++)
       {
@@ -588,7 +589,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)

         if (pinfo->next == NULL)
         {
-            fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr);
+            fprintf(STDERR, "Pointer %p not found\n", ptr);
            break;
         }

@@ -643,16 +644,16 @@ set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
 {
   int location;

-   if ((data->location[0] & what) || (data->location[1] & what))
+   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)
      return 0; /* already have one of these */

-   /* Find where we are (the code below zeros info_ptr to indicate that the
+   /* Find where we are (the code below zeroes info_ptr to indicate that the
    * chunks before the first IDAT have been read.)
    */
   if (data->info_ptr == NULL) /* after IDAT */
      location = what | after_IDAT;

-   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE))
+   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)
      location = what | before_IDAT;

   else
@@ -699,7 +700,7 @@ read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
         if (chunk->data[0] != 0 && chunk->data[0] != 1)
            return (-1);  /* Invalid mode */

-         if (set_location(png_ptr, my_user_chunk_data, have_sTER))
+         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
         {
            my_user_chunk_data->sTER_mode=chunk->data[0];
            return (1);
@@ -718,7 +719,7 @@ read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
   if (chunk->size != 9)
      return (-1); /* Error return */

-   if (!set_location(png_ptr, my_user_chunk_data, have_vpAg))
+   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
      return (0);  /* duplicate vpAg */

   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
@@ -1049,7 +1050,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int interlace_type, compression_type, filter_type;

      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
-          &color_type, &interlace_type, &compression_type, &filter_type))
+          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
      {
         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
            color_type, interlace_type, compression_type, filter_type);
@@ -1082,7 +1083,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
-         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y))
+         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1093,7 +1094,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_fixed_point gamma;

-      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1105,7 +1106,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
-         &red_y, &green_x, &green_y, &blue_x, &blue_y))
+         &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1116,7 +1117,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      double gamma;

-      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1130,7 +1131,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int compression_type;

      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
-                      &profile, &proflen))
+                      &profile, &proflen) != 0)
      {
         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
                      profile, proflen);
@@ -1141,7 +1142,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      int intent;

-      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
         png_set_sRGB(write_ptr, write_info_ptr, intent);
   }
 #endif
@@ -1149,14 +1150,14 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_colorp palette;
      int num_palette;

-      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
   }
 #ifdef PNG_bKGD_SUPPORTED
   {
      png_color_16p background;

-      if (png_get_bKGD(read_ptr, read_info_ptr, &background))
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
      {
         png_set_bKGD(write_ptr, write_info_ptr, background);
      }
@@ -1166,7 +1167,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_uint_16p hist;

-      if (png_get_hIST(read_ptr, read_info_ptr, &hist))
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
         png_set_hIST(write_ptr, write_info_ptr, hist);
   }
 #endif
@@ -1176,7 +1177,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int unit_type;

      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
-          &unit_type))
+          &unit_type) != 0)
      {
         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
      }
@@ -1190,7 +1191,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int type, nparams;

      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
-         &nparams, &units, &params))
+         &nparams, &units, &params) != 0)
      {
         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
            nparams, units, params);
@@ -1202,7 +1203,8 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_uint_32 res_x, res_y;
      int unit_type;

-      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
+          &unit_type) != 0)
         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
   }
 #endif
@@ -1210,7 +1212,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_color_8p sig_bit;

-      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
   }
 #endif
@@ -1222,7 +1224,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      double scal_width, scal_height;

      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
-         &scal_height))
+         &scal_height) != 0)
      {
         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
      }
@@ -1234,7 +1236,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_charp scal_width, scal_height;

      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
-          &scal_height))
+          &scal_height) != 0)
      {
         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
             scal_height);
@@ -1274,11 +1276,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
      {
         png_set_tIME(write_ptr, write_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1299,7 +1301,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_color_16p trans_color;

      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
-         &trans_color))
+         &trans_color) != 0)
      {
         int sample_max = (1 << bit_depth);
         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
@@ -1382,11 +1384,12 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      {
 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
+
         row_buf = (png_bytep)png_malloc(read_ptr,
            png_get_rowbytes(read_ptr, read_info_ptr));

-         pngtest_debug2("\t0x%08lx (%u bytes)", (unsigned long)row_buf,
-            png_get_rowbytes(read_ptr, read_info_ptr));
+         pngtest_debug2("\t0x%08lx (%lu bytes)", (unsigned long)row_buf,
+            (unsigned long)png_get_rowbytes(read_ptr, read_info_ptr));

 #endif /* !SINGLE_ROWBUF_ALLOC */
         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
@@ -1456,11 +1459,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time))
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
      {
         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1780,10 +1783,11 @@ main(int argc, char *argv[])
      }
   }

-   if (!multiple && argc == 3 + verbose)
+   if (multiple == 0 && argc == 3 + verbose)
     outname = argv[2 + verbose];

-   if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2))
+   if ((multiple == 0 && argc > 3 + verbose) ||
+       (multiple != 0 && argc < 2))
   {
     fprintf(STDERR,
       "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
@@ -1805,6 +1809,9 @@ main(int argc, char *argv[])
      {
         int kerror;
         fprintf(STDERR, "\n Testing %s:", argv[i]);
+#if PNG_DEBUG > 0
+         fprintf(STDERR, "\n");
+#endif
         kerror = test_one_file(argv[i], outname);
         if (kerror == 0)
         {
@@ -1819,7 +1826,7 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
            for (k = 0; k<256; k++)
-               if (filters_used[k])
+               if (filters_used[k] != 0)
                  fprintf(STDERR, " Filter %d was used %lu times\n",
                     k, (unsigned long)filters_used[k]);
 #endif
@@ -1850,9 +1857,9 @@ main(int argc, char *argv[])

            while (pinfo != NULL)
            {
-               fprintf(STDERR, " %lu bytes at %x\n",
+               fprintf(STDERR, " %lu bytes at %p\n",
                 (unsigned long)pinfo->size,
-                 (unsigned int)pinfo->pointer);
+                 pinfo->pointer);
               pinfo = pinfo->next;
            }
         }
@@ -1886,7 +1893,12 @@ main(int argc, char *argv[])
            status_dots_requested = 0;

         if (i == 0 || verbose == 1 || ierror != 0)
+         {
            fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+            fprintf(STDERR, "\n");
+#endif
+         }

         kerror = test_one_file(inname, outname);

@@ -1905,7 +1917,7 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
                for (k = 0; k<256; k++)
-                   if (filters_used[k])
+                   if (filters_used[k] != 0)
                      fprintf(STDERR, " Filter %d was used %lu times\n",
                         k, (unsigned long)filters_used[k]);
 #endif
@@ -1919,7 +1931,12 @@ main(int argc, char *argv[])
         else
         {
            if (verbose == 0 && i != 2)
+            {
               fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+               fprintf(STDERR, "\n");
+#endif
+            }

            fprintf(STDERR, " FAIL\n");
            ierror += kerror;
@@ -1938,8 +1955,8 @@ main(int argc, char *argv[])

             while (pinfo != NULL)
             {
-                fprintf(STDERR, " %lu bytes at %x\n",
-                   (unsigned long)pinfo->size, (unsigned int)pinfo->pointer);
+                fprintf(STDERR, " %lu bytes at %p\n",
+                   (unsigned long)pinfo->size, pinfo->pointer);
                pinfo = pinfo->next;
             }
          }
@@ -1991,4 +2008,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_13 Your_png_h_is_not_version_1_6_13;
+typedef png_libpng_version_1_6_15beta02 Your_png_h_is_not_version_1_6_15beta02;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,7 +1,7 @@

 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -100,7 +100,7 @@ png_set_interlace_handling(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_interlace handling");

-   if (png_ptr && png_ptr->interlaced)
+   if (png_ptr != 0 && png_ptr->interlaced != 0)
   {
      png_ptr->transformations |= PNG_INTERLACE;
      return (7);
@@ -127,7 +127,7 @@ png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
   /* In libpng 1.6 it is possible to determine whether this is a read or write
    * operation and therefore to do more checking here for a valid call.
    */
-   if (png_ptr->mode & PNG_IS_READ_STRUCT)
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
   {
 #     ifdef PNG_READ_FILLER_SUPPORTED
         /* On read png_set_filler is always valid, regardless of the base PNG
@@ -210,7 +210,7 @@ png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)

   png_set_filler(png_ptr, filler, filler_loc);
   /* The above may fail to do anything. */
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_ptr->transformations |= PNG_ADD_ALPHA;
 }

@@ -605,7 +605,7 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_bgr");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_uint_32 row_width = row_info->width;
      if (row_info->bit_depth == 8)
@@ -828,7 +828,7 @@ png_get_user_transform_ptr(png_const_structrp png_ptr)
 png_uint_32 PNGAPI
 png_get_current_row_number(png_const_structrp png_ptr)
 {
-   /* See the comments in png.h - this is the sub-image row when reading and
+   /* See the comments in png.h - this is the sub-image row when reading an
    * interlaced image.
    */
   if (png_ptr != NULL)
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -24,7 +24,7 @@ static void
 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
   unsigned int where)
 {
-   if (info_ptr->unknown_chunks_num)
+   if (info_ptr->unknown_chunks_num != 0)
   {
      png_const_unknown_chunkp up;

@@ -33,7 +33,7 @@ write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
      for (up = info_ptr->unknown_chunks;
           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
           ++up)
-         if (up->location & where)
+         if ((up->location & where) != 0)
      {
         /* If per-chunk unknown chunk handling is enabled use it, otherwise
          * just write the chunks the application has set.
@@ -88,14 +88,14 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
   {
   /* Write PNG signature */
   png_write_sig(png_ptr);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
-       (png_ptr->mng_features_permitted))
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+       png_ptr->mng_features_permitted != 0)
   {
      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
      png_ptr->mng_features_permitted = 0;
@@ -129,9 +129,9 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    */
 #ifdef PNG_GAMMA_SUPPORTED
 #  ifdef PNG_WRITE_gAMA_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&
-         (info_ptr->valid & PNG_INFO_gAMA))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
+          (info_ptr->valid & PNG_INFO_gAMA) != 0)
         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
 #  endif
 #endif
@@ -141,11 +141,11 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    * and it matches one of the known sRGB ones issue a warning.
    */
 #  ifdef PNG_WRITE_iCCP_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->valid & PNG_INFO_iCCP))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_iCCP) != 0)
      {
 #        ifdef PNG_WRITE_sRGB_SUPPORTED
-            if (info_ptr->valid & PNG_INFO_sRGB)
+            if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
               png_app_warning(png_ptr,
                  "profile matches sRGB but writing iCCP instead");
 #        endif
@@ -159,22 +159,22 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
 #  endif

 #  ifdef PNG_WRITE_sRGB_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->valid & PNG_INFO_sRGB))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_sRGB) != 0)
         png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
 #  endif /* WRITE_sRGB */
 #endif /* COLORSPACE */

 #ifdef PNG_WRITE_sBIT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sBIT)
+   if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
 #endif

 #ifdef PNG_COLORSPACE_SUPPORTED
 #  ifdef PNG_WRITE_cHRM_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&
-         (info_ptr->valid & PNG_INFO_cHRM))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+         (info_ptr->valid & PNG_INFO_cHRM) != 0)
         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
 #  endif
 #endif
@@ -201,19 +201,19 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)

   png_write_info_before_PLTE(png_ptr, info_ptr);

-   if (info_ptr->valid & PNG_INFO_PLTE)
+   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
      png_write_PLTE(png_ptr, info_ptr->palette,
          (png_uint_32)info_ptr->num_palette);

-   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
      png_error(png_ptr, "Valid palette required for paletted images");

 #ifdef PNG_WRITE_tRNS_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tRNS)
+   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
   {
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      /* Invert the alpha channel (in tRNS) */
-      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         int j;
@@ -227,42 +227,42 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
   }
 #endif
 #ifdef PNG_WRITE_bKGD_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_bKGD)
+   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
 #endif

 #ifdef PNG_WRITE_hIST_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_hIST)
+   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
 #endif

 #ifdef PNG_WRITE_oFFs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_oFFs)
+   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
          info_ptr->offset_unit_type);
 #endif

 #ifdef PNG_WRITE_pCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pCAL)
+   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
          info_ptr->pcal_units, info_ptr->pcal_params);
 #endif

 #ifdef PNG_WRITE_sCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sCAL)
+   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
          info_ptr->scal_s_width, info_ptr->scal_s_height);
 #endif /* sCAL */

 #ifdef PNG_WRITE_pHYs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pHYs)
+   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
 #endif /* pHYs */

 #ifdef PNG_WRITE_tIME_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tIME)
+   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
   {
      png_write_tIME(png_ptr, &(info_ptr->mod_time));
      png_ptr->mode |= PNG_WROTE_tIME;
@@ -270,7 +270,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #endif /* tIME */

 #ifdef PNG_WRITE_sPLT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sPLT)
+   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
 #endif /* sPLT */
@@ -292,11 +292,14 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
             info_ptr->text[i].lang,
             info_ptr->text[i].lang_key,
             info_ptr->text[i].text);
+         /* Mark this chunk as written */
+         if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         else
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
-          png_warning(png_ptr, "Unable to write international text");
+         png_warning(png_ptr, "Unable to write international text");
 #endif
-          /* Mark this chunk as written */
-          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
      }

      /* If we want a compressed text chunk */
@@ -305,13 +308,12 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
         /* Write compressed chunk */
         png_write_zTXt(png_ptr, info_ptr->text[i].key,
-             info_ptr->text[i].text, 0,
-             info_ptr->text[i].compression);
+             info_ptr->text[i].text, info_ptr->text[i].compression);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
         png_warning(png_ptr, "Unable to write compressed text");
 #endif
-         /* Mark this chunk as written */
-         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
      }

      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -349,7 +351,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
   if (png_ptr == NULL)
      return;

-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
      png_error(png_ptr, "No IDATs written into file");

 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
@@ -365,8 +367,8 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #endif
 #ifdef PNG_WRITE_tIME_SUPPORTED
      /* Check to see if user has supplied a time chunk */
-      if ((info_ptr->valid & PNG_INFO_tIME) &&
-          !(png_ptr->mode & PNG_WROTE_tIME))
+      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+          (png_ptr->mode & PNG_WROTE_tIME) == 0)
         png_write_tIME(png_ptr, &(info_ptr->mod_time));

 #endif
@@ -387,11 +389,14 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
                info_ptr->text[i].lang,
                info_ptr->text[i].lang_key,
                info_ptr->text[i].text);
+            /* Mark this chunk as written */
+            if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+            else
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
            png_warning(png_ptr, "Unable to write international text");
 #endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }

         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
@@ -399,13 +404,12 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
            /* Write compressed chunk */
            png_write_zTXt(png_ptr, info_ptr->text[i].key,
-                info_ptr->text[i].text, 0,
-                info_ptr->text[i].compression);
+                info_ptr->text[i].text, info_ptr->text[i].compression);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
            png_warning(png_ptr, "Unable to write compressed text");
 #endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
         }

         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -414,12 +418,11 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
            /* Write uncompressed chunk */
            png_write_tEXt(png_ptr, info_ptr->text[i].key,
                info_ptr->text[i].text, 0);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
 #else
            png_warning(png_ptr, "Unable to write uncompressed text");
 #endif
-
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }
      }
 #endif
@@ -615,7 +618,7 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_write_intrapixel");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -690,44 +693,44 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
   {
      /* Make sure we wrote the header info */
-      if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
         png_error(png_ptr,
             "png_write_info was never called before png_write_row");

      /* Check for transforms that have been set but were defined out */
 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
-      if (png_ptr->transformations & PNG_INVERT_MONO)
+      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
-      if (png_ptr->transformations & PNG_FILLER)
+      if ((png_ptr->transformations & PNG_FILLER) != 0)
         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
 #endif
 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
    defined(PNG_READ_PACKSWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACKSWAP)
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
         png_warning(png_ptr,
             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACK)
+      if ((png_ptr->transformations & PNG_PACK) != 0)
         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
-      if (png_ptr->transformations & PNG_SHIFT)
+      if ((png_ptr->transformations & PNG_SHIFT) != 0)
         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
-      if (png_ptr->transformations & PNG_BGR)
+      if ((png_ptr->transformations & PNG_BGR) != 0)
         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_SWAP_BYTES)
+      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
 #endif

@@ -736,12 +739,13 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced and not interested in row, return */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      switch (png_ptr->pass)
      {
         case 0:
-            if (png_ptr->row_number & 0x07)
+            if ((png_ptr->row_number & 0x07) != 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -749,7 +753,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 1:
-            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -765,7 +769,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 3:
-            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
+            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -781,7 +785,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 5:
-            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
+            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -789,7 +793,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 6:
-            if (!(png_ptr->row_number & 0x01))
+            if ((png_ptr->row_number & 0x01) == 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -823,7 +827,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* Handle interlacing */
   if (png_ptr->interlaced && png_ptr->pass < 6 &&
-       (png_ptr->transformations & PNG_INTERLACE))
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
      /* This should always get caught above, but still ... */
@@ -837,7 +841,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
   /* Handle other transformations */
-   if (png_ptr->transformations)
+   if (png_ptr->transformations != 0)
      png_do_write_transformations(png_ptr, &row_info);
 #endif

@@ -858,7 +862,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
    * 4. The filter_method is 64 and
    * 5. The color_type is RGB or RGBA
    */
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -924,18 +928,24 @@ png_write_destroy(png_structrp png_ptr)
   png_debug(1, "in png_write_destroy");

   /* Free any memory zlib uses */
-   if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
      deflateEnd(&png_ptr->zstream);

   /* Free our memory.  png_free checks NULL for us. */
   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
   png_free(png_ptr, png_ptr->row_buf);
+   png_ptr->row_buf = NULL;
 #ifdef PNG_WRITE_FILTER_SUPPORTED
   png_free(png_ptr, png_ptr->prev_row);
   png_free(png_ptr, png_ptr->sub_row);
   png_free(png_ptr, png_ptr->up_row);
   png_free(png_ptr, png_ptr->avg_row);
   png_free(png_ptr, png_ptr->paeth_row);
+   png_ptr->prev_row = NULL;
+   png_ptr->sub_row = NULL;
+   png_ptr->up_row = NULL;
+   png_ptr->avg_row = NULL;
+   png_ptr->paeth_row = NULL;
 #endif

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
@@ -943,10 +953,13 @@ png_write_destroy(png_structrp png_ptr)
   png_reset_filter_heuristics(png_ptr);
   png_free(png_ptr, png_ptr->filter_costs);
   png_free(png_ptr, png_ptr->inv_filter_costs);
+   png_ptr->filter_costs = NULL;
+   png_ptr->inv_filter_costs = NULL;
 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
 #endif

   /* The error handling and memory handling information is left intact at this
@@ -992,7 +1005,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      return;

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
      method = PNG_FILTER_TYPE_BASE;

@@ -1043,14 +1056,16 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      if (png_ptr->row_buf != NULL)
      {
 #ifdef PNG_WRITE_FILTER_SUPPORTED
-         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
+             png_ptr->sub_row == NULL)
         {
            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
                (png_ptr->rowbytes + 1));
            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
         }

-         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
+              png_ptr->up_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1067,7 +1082,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
+              png_ptr->avg_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1084,7 +1100,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0 &&
             png_ptr->paeth_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
@@ -1245,7 +1261,7 @@ png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1300,7 +1316,7 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1559,7 +1575,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   /* ------ these transformations don't touch the info structure ------- */

   /* Invert monochrome pixels */
-   if (transforms & PNG_TRANSFORM_INVERT_MONO)
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
 #ifdef PNG_WRITE_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1569,16 +1585,16 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Shift the pixels up to a legal bit depth and fill in
    * as appropriate to correctly scale the image.
    */
-   if (transforms & PNG_TRANSFORM_SHIFT)
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-      if (info_ptr->valid & PNG_INFO_sBIT)
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
         png_set_shift(png_ptr, &info_ptr->sig_bit);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
 #endif

   /* Pack pixels into bytes */
-   if (transforms & PNG_TRANSFORM_PACKING)
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
 #ifdef PNG_WRITE_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1586,7 +1602,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap location of alpha bytes from ARGB to RGBA */
-   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1597,13 +1613,13 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
    * RGB, note that the code expects the input color type to be G or RGB; no
    * alpha channel.
    */
-   if (transforms &
-      (PNG_TRANSFORM_STRIP_FILLER_AFTER|PNG_TRANSFORM_STRIP_FILLER_BEFORE))
+   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+      PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
   {
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-      if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
+      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
      {
-         if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
+         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
            png_app_error(png_ptr,
               "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");

@@ -1611,7 +1627,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
         png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
      }

-      else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
+      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
@@ -1619,7 +1635,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   }

   /* Flip BGR pixels to RGB */
-   if (transforms & PNG_TRANSFORM_BGR)
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
 #ifdef PNG_WRITE_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1627,7 +1643,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bytes of 16-bit files to most significant byte first */
-   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
 #ifdef PNG_WRITE_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1635,7 +1651,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bits of 1, 2, 4 bit packed pixel formats */
-   if (transforms & PNG_TRANSFORM_PACKSWAP)
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1643,7 +1659,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Invert the alpha channel from opacity to transparency */
-   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1734,14 +1750,14 @@ png_write_image_16bit(png_voidp argument)
      display->first_row);
   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
   png_uint_16p row_end;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
   int aindex = 0;
   png_uint_32 y = image->height;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1891,15 +1907,15 @@ png_write_image_8bit(png_voidp argument)
      display->first_row);
   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
   png_uint_32 y = image->height;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
      png_bytep row_end;
      int aindex;

 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1996,7 +2012,7 @@ png_image_set_PLTE(png_image_write_control *display)
 #  endif

 #  ifdef PNG_FORMAT_BGR_SUPPORTED
-      const int bgr = (format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
+      const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
 #  else
 #     define bgr 0
 #  endif
@@ -2013,13 +2029,13 @@ png_image_set_PLTE(png_image_write_control *display)
      /* This gets automatically converted to sRGB with reversal of the
       * pre-multiplication if the color-map has an alpha channel.
       */
-      if (format & PNG_FORMAT_FLAG_LINEAR)
+      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
      {
         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);

         entry += i * channels;

-         if (channels & 1) /* no alpha */
+         if ((channels & 1) != 0) /* no alpha */
         {
            if (channels >= 3) /* RGB */
            {
@@ -2131,10 +2147,11 @@ png_image_write_main(png_voidp argument)
   png_inforp info_ptr = image->opaque->info_ptr;
   png_uint_32 format = image->format;

-   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP) != 0;
-   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR) != 0; /* input */
-   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0;
-   int write_16bit = linear && !colormap && !display->convert_to_8bit;
+   /* The following four ints are actually booleans */
+   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+   int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);

 #  ifdef PNG_BENIGN_ERRORS_SUPPORTED
      /* Make sure we error out on any bad situation */
@@ -2146,7 +2163,7 @@ png_image_write_main(png_voidp argument)
      display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);

   /* Set the required transforms then write the rows in the correct order. */
-   if (format & PNG_FORMAT_FLAG_COLORMAP)
+   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
   {
      if (display->colormap != NULL && image->colormap_entries > 0)
      {
@@ -2183,7 +2200,7 @@ png_image_write_main(png_voidp argument)
      /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);

-      if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
+      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
         png_set_cHRM_fixed(png_ptr, info_ptr,
            /* color      x       y */
            /* white */ 31270, 32900,
@@ -2193,7 +2210,7 @@ png_image_write_main(png_voidp argument)
         );
   }

-   else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
+   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
      png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);

   /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
@@ -2214,23 +2231,23 @@ png_image_write_main(png_voidp argument)
   {
      PNG_CONST png_uint_16 le = 0x0001;

-      if (*(png_const_bytep)&le)
+      if ((*(png_const_bytep) & le) != 0)
         png_set_swap(png_ptr);
   }

 #  ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_BGR)
+      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_bgr(png_ptr);
         format &= ~PNG_FORMAT_FLAG_BGR;
      }
 #  endif

 #  ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_AFIRST)
+      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
            png_set_swap_alpha(png_ptr);
         format &= ~PNG_FORMAT_FLAG_AFIRST;
      }
@@ -2239,7 +2256,7 @@ png_image_write_main(png_voidp argument)
   /* If there are 16 or fewer color-map entries we wrote a lower bit depth
    * above, but the application data is still byte packed.
    */
-   if (colormap && image->colormap_entries <= 16)
+   if (colormap != 0 && image->colormap_entries <= 16)
      png_set_packing(png_ptr);

   /* That should have handled all (both) the transforms. */
@@ -2277,7 +2294,8 @@ png_image_write_main(png_voidp argument)
    * before it is written.  This only applies when the input is 16-bit and
    * either there is an alpha channel or it is converted to 8-bit.
    */
-   if ((linear && alpha) || (!colormap && display->convert_to_8bit))
+   if ((linear != 0 && alpha != 0 ) ||
+       (colormap == 0 && display->convert_to_8bit != 0))
   {
      png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
         png_get_rowbytes(png_ptr, info_ptr)));
@@ -2326,7 +2344,7 @@ png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
   {
      if (file != NULL)
      {
-         if (png_image_write_init(image))
+         if (png_image_write_init(image) != 0)
         {
            png_image_write_control display;
            int result;
@@ -2381,7 +2399,7 @@ png_image_write_to_file(png_imagep image, const char *file_name,
         if (fp != NULL)
         {
            if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
-               row_stride, colormap))
+               row_stride, colormap) != 0)
            {
               int error; /* from fflush/fclose */

--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@

 /* pngwtran.c - transforms the data in a row for PNG writers
 *
- * Last changed in libpng 1.6.9 [February 6, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -177,7 +177,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
      int shift_start[4], shift_dec[4];
      int channels = 0;

-      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->red;
         shift_dec[channels] = bit_depth->red;
@@ -199,7 +199,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
         channels++;
      }

-      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
         shift_dec[channels] = bit_depth->alpha;
@@ -505,7 +505,7 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
      return;

 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
      if (png_ptr->write_user_transform_fn != NULL)
         (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                 function */
@@ -521,50 +521,50 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
 #endif

 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_do_pack(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->bit_depth);
 #endif

 #ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_do_swap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      png_do_shift(row_info, png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif

 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif
 }
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [(PENDING RELEASE)]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -136,7 +136,7 @@ png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
      png_write_data(png_ptr, data, length);

      /* Update the CRC after writing the data,
-       * in case that the user I/O routine alters it.
+       * in case the user I/O routine alters it.
       */
      png_calculate_crc(png_ptr, data, length);
   }
@@ -181,7 +181,7 @@ png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,

   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
   if (length > PNG_UINT_31_MAX)
-      png_error(png_ptr, "length exceeds PNG maxima");
+      png_error(png_ptr, "length exceeds PNG maximum");

   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
   png_write_chunk_data(png_ptr, data, length);
@@ -204,14 +204,14 @@ png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
 static png_alloc_size_t
 png_image_size(png_structrp png_ptr)
 {
-   /* Only return sizes up to the maximum of a png_uint_32, do this by limiting
+   /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
    * the width and height used to 15 bits.
    */
   png_uint_32 h = png_ptr->height;

   if (png_ptr->rowbytes < 32768 && h < 32768)
   {
-      if (png_ptr->interlaced)
+      if (png_ptr->interlaced != 0)
      {
         /* Interlacing makes the image larger because of the replication of
          * both the filter byte and the padding to a byte boundary.
@@ -286,8 +286,6 @@ optimize_cmf(png_bytep data, png_alloc_size_t data_size)
      }
   }
 }
-#else
-#  define optimize_cmf(dp,dl) ((void)0)
 #endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */

 /* Initialize the compressor for the appropriate type of compression. */
@@ -297,6 +295,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
 {
   if (png_ptr->zowner != 0)
   {
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
      char msg[64];

      PNG_STRING_FROM_CHUNK(msg, owner);
@@ -308,7 +307,8 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
       * are minimal.
       */
      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
-#     if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#endif
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
         png_warning(png_ptr, msg);

         /* Attempt sane error recovery */
@@ -319,9 +319,9 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
         }

         png_ptr->zowner = 0;
-#     else
+#else
         png_error(png_ptr, msg);
-#     endif
+#endif
   }

   {
@@ -334,7 +334,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      if (owner == png_IDAT)
      {
-         if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
+         if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
            strategy = png_ptr->zlib_strategy;

         else if (png_ptr->do_filter != PNG_FILTER_NONE)
@@ -346,20 +346,20 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      else
      {
-#        ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
            level = png_ptr->zlib_text_level;
            method = png_ptr->zlib_text_method;
            windowBits = png_ptr->zlib_text_window_bits;
            memLevel = png_ptr->zlib_text_mem_level;
            strategy = png_ptr->zlib_text_strategy;
-#        else
+#else
            /* If customization is not supported the values all come from the
             * IDAT values except for the strategy, which is fixed to the
             * default.  (This is the pre-1.6.0 behavior too, although it was
             * implemented in a very different way.)
             */
            strategy = Z_DEFAULT_STRATEGY;
-#        endif
+#endif
      }

      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
@@ -386,7 +386,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      }

      /* Check against the previous initialized values, if any. */
-      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
         (png_ptr->zlib_set_level != level ||
         png_ptr->zlib_set_method != method ||
         png_ptr->zlib_set_window_bits != windowBits ||
@@ -410,7 +410,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      /* Now initialize if required, setting the new parameters, otherwise just
       * to a simple reset to the previous parameters.
       */
-      if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
         ret = deflateReset(&png_ptr->zstream);

      else
@@ -492,7 +492,7 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
   int ret;

   /* To find the length of the output it is necessary to first compress the
-    * input, the result is buffered rather than using the two-pass algorithm
+    * input. The result is buffered rather than using the two-pass algorithm
    * that is used on the inflate side; deflate is assumed to be slower and a
    * PNG writer is assumed to have more memory available than a PNG reader.
    *
@@ -589,7 +589,7 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
      }
      while (ret == Z_OK);

-      /* There may be some space left in the last output buffer, this needs to
+      /* There may be some space left in the last output buffer. This needs to
       * be subtracted from output_len.
       */
      output_len -= png_ptr->zstream.avail_out;
@@ -612,14 +612,15 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
      /* Reset zlib for another zTXt/iTXt or image data */
      png_ptr->zowner = 0;

-      /* The only success case is Z_STREAM_END, input_len must be 0, if not this
+      /* The only success case is Z_STREAM_END, input_len must be 0; if not this
       * is an internal error.
       */
      if (ret == Z_STREAM_END && input_len == 0)
      {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
         /* Fix up the deflate header, if required */
         optimize_cmf(comp->output, comp->input_len);
-
+#endif
         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
          * function above to return Z_STREAM_END on an error (though it never
          * does in the current versions of zlib.)
@@ -715,7 +716,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
         bad_character = ch; /* just skip it, record the first error */
   }

-   if (key_len > 0 && space) /* trailing space */
+   if (key_len > 0 && space != 0) /* trailing space */
   {
      --key_len, --new_key;
      if (bad_character == 0)
@@ -728,8 +729,9 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
   if (key_len == 0)
      return 0;

+#ifdef PNG_WARNINGS_SUPPORTED
   /* Try to only output one warning per keyword: */
-   if (*key) /* keyword too long */
+   if (*key != 0) /* keyword too long */
      png_warning(png_ptr, "keyword truncated");

   else if (bad_character != 0)
@@ -741,6 +743,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
   }
+#endif /* PNG_WARNINGS_SUPPORTED */

   return key_len;
 }
@@ -845,8 +848,8 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
    */
   if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
       (color_type == PNG_COLOR_TYPE_RGB ||
        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
@@ -927,7 +930,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,

   if ((
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+       (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
 #endif
       num_pal == 0) || num_pal > 256)
   {
@@ -943,7 +946,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
      }
   }

-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
   {
      png_warning(png_ptr,
          "Ignoring request to write a PLTE chunk in grayscale PNG");
@@ -998,7 +1001,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
 * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
 *
 * The routine manages the acquire and release of the png_ptr->zstream by
- * checking and (at the end) clearing png_ptr->zowner, it does some sanity
+ * checking and (at the end) clearing png_ptr->zowner; it does some sanity
 * checks on the 'mode' flags while doing this.
 */
 void /* PRIVATE */
@@ -1058,7 +1061,7 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
      input_len += png_ptr->zstream.avail_in;
      png_ptr->zstream.avail_in = 0;

-      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note
+      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
       * that these two zstream fields are preserved across the calls, therefore
       * there is no need to set these up on entry to the loop.
       */
@@ -1070,11 +1073,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         /* Write an IDAT containing the data then reset the buffer.  The
          * first IDAT may need deflate header optimization.
          */
-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+                png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->mode |= PNG_HAVE_IDAT;
@@ -1090,7 +1093,7 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
            continue;
      }

-      /* The order of these checks doesn't matter much; it just effect which
+      /* The order of these checks doesn't matter much; it just affects which
       * possible error might be detected if multiple things go wrong at once.
       */
      if (ret == Z_OK) /* most likely return code! */
@@ -1116,11 +1119,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         png_bytep data = png_ptr->zbuffer_list->output;
         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;

-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
-               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+             png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+            optimize_cmf(data, png_image_size(png_ptr));
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->zstream.avail_out = 0;
@@ -1341,7 +1344,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
   png_debug(1, "in png_write_sBIT");

   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_byte maxbits;

@@ -1374,7 +1377,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
      size = 1;
   }

-   if (color_type & PNG_COLOR_MASK_ALPHA)
+   if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
   {
      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
      {
@@ -1461,9 +1464,9 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
      png_save_uint_16(buf + 2, tran->green);
      png_save_uint_16(buf + 4, tran->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_app_warning(png_ptr,
@@ -1494,8 +1497,8 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
   {
      if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-          (png_ptr->num_palette ||
-          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+          (png_ptr->num_palette != 0 ||
+          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
 #endif
         back->index >= png_ptr->num_palette)
      {
@@ -1507,15 +1510,15 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
   }

-   else if (color_type & PNG_COLOR_MASK_COLOR)
+   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_save_uint_16(buf, back->red);
      png_save_uint_16(buf + 2, back->green);
      png_save_uint_16(buf + 4, back->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_warning(png_ptr,
@@ -1621,14 +1624,13 @@ png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
 /* Write a compressed text chunk */
 void /* PRIVATE */
 png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len, int compression)
+    int compression)
 {
   png_uint_32 key_len;
   png_byte new_key[81];
   compression_state comp;

   png_debug(1, "in png_write_zTXt");
-   PNG_UNUSED(text_len) /* Always use strlen */

   if (compression == PNG_TEXT_COMPRESSION_NONE)
   {
@@ -1983,12 +1985,13 @@ png_write_start_row(png_structrp png_ptr)
   }

   /* We only need to keep the previous row if we are using one of these. */
-   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+   if ((png_ptr->do_filter &
+      (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
   {
      /* Set up previous row buffer */
      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);

-      if (png_ptr->do_filter & PNG_FILTER_UP)
+      if ((png_ptr->do_filter & PNG_FILTER_UP) != 0)
      {
         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
            png_ptr->rowbytes + 1);
@@ -1996,7 +1999,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
      }

-      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0)
      {
         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2004,7 +2007,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
      }

-      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0)
      {
         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2016,9 +2019,9 @@ png_write_start_row(png_structrp png_ptr)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, we need to set up width and height of pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
      {
         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
             png_pass_ystart[0]) / png_pass_yinc[0];
@@ -2073,10 +2076,10 @@ png_write_finish_row(png_structrp png_ptr)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, go to next pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
-      if (png_ptr->transformations & PNG_INTERLACE)
+      if ((png_ptr->transformations & PNG_INTERLACE) != 0)
      {
         png_ptr->pass++;
      }
@@ -2101,7 +2104,7 @@ png_write_finish_row(png_structrp png_ptr)
                png_pass_ystart[png_ptr->pass]) /
                png_pass_yinc[png_ptr->pass];

-            if (png_ptr->transformations & PNG_INTERLACE)
+            if ((png_ptr->transformations & PNG_INTERLACE) != 0)
               break;

         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
@@ -2380,7 +2383,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* We don't need to test the 'no filter' case if this is the only filter
    * that has been chosen, as it doesn't actually do anything to the data.
    */
-   if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
+   if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
   {
      png_bytep rp;
      png_uint_32 sum = 0;
@@ -2456,7 +2459,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->sub_row;
   }

-   else if (filter_to_do & PNG_FILTER_SUB)
+   else if ((filter_to_do & PNG_FILTER_SUB) != 0)
   {
      png_bytep rp, dp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2577,7 +2580,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->up_row;
   }

-   else if (filter_to_do & PNG_FILTER_UP)
+   else if ((filter_to_do & PNG_FILTER_UP) != 0)
   {
      png_bytep rp, dp, pp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2691,7 +2694,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->avg_row;
   }

-   else if (filter_to_do & PNG_FILTER_AVG)
+   else if ((filter_to_do & PNG_FILTER_AVG) != 0)
   {
      png_bytep rp, dp, pp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2793,7 +2796,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   }

   /* Paeth filter */
-   if (filter_to_do == PNG_FILTER_PAETH)
+   if ((filter_to_do == PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_size_t i;
@@ -2832,7 +2835,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->paeth_row;
   }

-   else if (filter_to_do & PNG_FILTER_PAETH)
+   else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_uint_32 sum = 0, lmins = mins;
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.13 - August 21, 2014
+libpng version 1.6.15beta02 - November 1, 2014

 Copyright (c) 1998-2010 Glenn Randers-Pehrson

--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.6.13 - August 21, 2014
+ * libpng version 1.6.15beta02 - November 1, 2014
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.13 - August 21, 2014
+Makefiles for  libpng version 1.6.15beta02 - November 1, 2014

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.13)
+                       (gcc, creates libpng16.so.16.1.6.15beta02)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -33,12 +33,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng16.so.16.1.6.13)
+                       creates libpng16.so.16.1.6.15beta02)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.13)
+                       creates libpng16.so.16.1.6.15beta02)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.13)
+                       creates libpng16.so.16.1.6.15beta02)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.dfn
+++ b/scripts/def.dfn
@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.6.13"
+PNG_DFN ";Version 1.6.15beta02"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.6.13
+version=1.6.15beta02
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.13
+Version: 1.6.15beta02
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -23,7 +23,7 @@

 VERMAJ = 1
 VERMIN = 6
-VERMIC = 13
+VERMIC = 15
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -10,7 +10,7 @@
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 13
+RELEASE = 15

 # Shared library names:
 LIBSO=$(LIBNAME).so
--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -18,7 +18,7 @@ exec_prefix=$(prefix)
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 13
+RELEASE = 15

 # Shared library names:
 LIBSO=$(LIBNAME).dll
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include/libpng16

 LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.6.13
+SHLIB_MINOR=	1.6.15beta02
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include

 LIB=	png
 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.13
+SHLIB_MINOR=	1.6.15beta02
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.13
+SHLIB_MINOR=	1.6.15beta02

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/options.awk
+++ b/scripts/options.awk
@@ -1,9 +1,9 @@
 #!/bin/awk -f
 # scripts/options.awk - library build configuration control
 #
-# last changed in libpng version 1.5.7 - December 15, 2011
+# last changed in libpng version 1.6.11 - June 5, 2014
 #
-# Copyright (c) 1998-2011 Glenn Randers-Pehrson
+# Copyright (c) 1998-2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -8,7 +8,7 @@ com pnglibconf.h - library build configuration
 com
 version
 com
-com Copyright (c) 1998-2012 Glenn Randers-Pehrson
+com Copyright (c) 1998-2014 Glenn Randers-Pehrson
 com
 com This code is released under the libpng license.
 com For conditions of distribution and use, see the disclaimer
@@ -114,6 +114,13 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H

 logunsupported = 1

+# The following allows the output from configure to modify the contents of
+# pnglibconf.h
+
+@#ifdef HAVE_CONFIG_H
+@#  include "config.h"
+@#endif
+
 # PNG_USER_CONFIG has to be defined on the compiler command line
 # to cause pngusr.h to be read while constructing pnglibconf.h
 #
@@ -189,10 +196,6 @@ setting API_RULE default 0

 setting PREFIX

-# Default to using the read macros
-
-setting DEFAULT_READ_MACROS default 1
-
 # Implementation specific control of the optimizations, enabled by those
 # hardware or software options that need it (typically when run-time choices
 # must be made by the user)
@@ -227,19 +230,21 @@ option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
   sets ARM_NEON_OPT 1

 # These settings configure the default compression level (0-9) and 'strategy';
-# strategy is as defined by the implementors of zlib, it describes the input
+# strategy is as defined by the implementors of zlib. It describes the input
 # data and modifies the zlib parameters in an attempt to optimize the balance
 # between search and huffman encoding in the zlib algorithms.  The defaults are
 # the zlib.h defaults - the apparently recursive definition does not arise
 # because the name of the setting is prefixed by PNG_
 #
 # The TEXT values are the defaults when writing compressed text (all forms)
-#
-# Include the zlib header too, so that the defaults below are known
+
+# Include the zlib header so that the defaults below are known
@#  include <zlib.h>

 # The '@' here means to substitute the value when pnglibconf.h is built
 setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+# TODO: why aren't these Z_RLE; zlib.h says that Z_RLE, specifically, is
+# appropriate for PNG images, maybe it doesn't exist in all versions?
 setting Z_DEFAULT_STRATEGY default @Z_FILTERED
 setting Z_DEFAULT_NOFILTER_STRATEGY default @Z_DEFAULT_STRATEGY
 setting ZLIB_VERNUM default @ZLIB_VERNUM
@@ -247,6 +252,10 @@ setting ZLIB_VERNUM default @ZLIB_VERNUM
 setting TEXT_Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
 setting TEXT_Z_DEFAULT_STRATEGY default @Z_DEFAULT_STRATEGY

+# Default to using the read macros
+
+setting DEFAULT_READ_MACROS default 1
+
 # The alternative is to call functions to read PNG values, if
 # the functions are turned *off* the read macros must always
 # be enabled, so turning this off will actually force the
@@ -370,7 +379,16 @@ option SET_USER_LIMITS enables SET_CHUNK_MALLOC_LIMIT
 #
 # If these settings are *not* set libpng will not limit the size of
 # images or the size of data in ancilliary chunks.  This does lead to
-# security issues if PNG files come from untrusted sources.
+# security issues if PNG files come from untrusted sources.  Settings have the
+# following interpretations:
+#
+# USER_WIDTH_MAX: maximum width of an image that will be read
+# USER_HEIGHT_MAX: maximum height
+# USER_CHUNK_MALLOC_MAX: maximum in-memory (decompressed) size of a single chunk
+# USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
+#
+# Only chunks that are variable in number are counted towards the
+# USER_CHUNK_CACHE_MAX limit
 setting USER_WIDTH_MAX
 setting USER_HEIGHT_MAX
 setting USER_CHUNK_CACHE_MAX
@@ -714,7 +732,7 @@ chunk cHRM enables COLORSPACE
 chunk gAMA enables GAMMA
 chunk hIST
 chunk iCCP enables COLORSPACE, GAMMA
-chunk iTXt
+chunk iTXt enables TEXT
 chunk oFFs
 chunk pCAL
 chunk pHYs
@@ -725,7 +743,7 @@ chunk sRGB enables COLORSPACE, GAMMA, SET_OPTION
 chunk tEXt requires TEXT
 chunk tIME
 chunk tRNS
-chunk zTXt
+chunk zTXt enables TEXT

 # This only affects support of the optional PLTE chunk in RGB and RGBA
 # images.  Notice that READ_ANCILLARY_CHUNKS therefore disables part
@@ -809,9 +827,9 @@ option SAVE_INT_32 disabled
 option WRITE_OPTIMIZE_CMF requires WRITE

 option READ_COMPRESSED_TEXT disabled
+option READ_iCCP enables READ_COMPRESSED_TEXT
 option READ_iTXt enables READ_COMPRESSED_TEXT
 option READ_zTXt enables READ_COMPRESSED_TEXT
-option READ_COMPRESSED_TEXT enables READ_TEXT

 option WRITE_oFFs enables SAVE_INT_32
 option WRITE_pCAL enables SAVE_INT_32
@@ -821,7 +839,6 @@ option WRITE_COMPRESSED_TEXT disabled
 option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
 option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
 option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
-option WRITE_COMPRESSED_TEXT enables WRITE_TEXT

 # Turn this off to disable png_read_png() and png_write_png() and
 # leave the row_pointers member out of the info structure.
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.13 STANDARD API DEFINITION */
+/* libpng 1.6.15beta02 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.13 - August 21, 2014 */
+/* Libpng version 1.6.15beta02 - November 1, 2014 */

 /* Copyright (c) 1998-2014 Glenn Randers-Pehrson */

--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.13
+;Version 1.6.15beta02
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
Author	SHA1	Message	Date
Glenn Randers-Pehrson	b75c3cc415	[libpng16] Imported from libpng-1.6.15beta02.tar	2014-11-01 18:59:08 -05:00
Glenn Randers-Pehrson	b963feeec6	[libpng16] More cosmetic changes	2014-11-01 13:18:36 -05:00
Glenn Randers-Pehrson	f2d4167fee	[libpng16] Added a pair of parentheses suggested by clang	2014-10-31 21:17:11 -05:00
Glenn Randers-Pehrson	5d713fe123	[libpng16] Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"	2014-10-31 20:58:40 -05:00
Glenn Randers-Pehrson	6b9a20e7f9	[libpng16] Bump version to 1.6.15beta02	2014-10-29 09:13:06 -05:00
Glenn Randers-Pehrson	11d4a2a451	[libpng16] Imported from libpng-1.6.15beta01.tar	2014-10-29 09:08:46 -05:00
Glenn Randers-Pehrson	c6a8cb7d10	[libpng16] Added missing "ptr = NULL" after some instances of png_free().	2014-10-29 08:27:34 -05:00
Glenn Randers-Pehrson	7f6826368a	[libpng16] Use %p instead of %x to print pointers in pngtest debug output	2014-10-28 10:22:37 -05:00
Glenn Randers-Pehrson	bf95fad5f5	[libpng16] Simplified png_free_data() in png.c	2014-10-26 21:09:03 -05:00
Glenn Randers-Pehrson	ebba0746bc	[libpng16] Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x !== 0)"	2014-10-25 12:22:39 -05:00
Glenn Randers-Pehrson	67152e75e6	[libpng16] Revised INSTALL document.	2014-10-24 22:29:51 -05:00
Glenn Randers-Pehrson	4aa3f403f1	[libpng16] Updated INSTALL file.	2014-10-24 21:45:38 -05:00
Glenn Randers-Pehrson	56e9307d8f	[libpng16] Bump version to 1.6.15beta01	2014-10-22 21:02:27 -05:00
Glenn Randers-Pehrson	edb772fd6d	[libpng16] Imported from libpng-1.6.14.tar	2014-10-22 19:32:52 -05:00
Glenn Randers-Pehrson	e557fd7c44	[libpng16] Minor editing of README	2014-10-17 09:31:48 -05:00
Glenn Randers-Pehrson	8ba743d8d2	[libpng16] Bump version to 1.6.14rc03	2014-10-17 09:15:50 -05:00
Glenn Randers-Pehrson	279205664f	[libpng16] Imported from libpng-1.6.14rc02.tar	2014-10-17 09:09:54 -05:00
Glenn Randers-Pehrson	f7a7bb0384	[libpng16] Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer() in the manual, to reflect the change made in libpng-1.6.0. Updated README file to reflect that direct access to the info struct and png struct are not permitted since libpng-1.5.0.	2014-10-17 09:06:25 -05:00
Glenn Randers-Pehrson	3922544139	[libpng16] Bump version to 1.6.14rc01	2014-10-15 08:55:59 -05:00
Glenn Randers-Pehrson	bea9784db0	[libpng16] Imported from libpng-1.6.14rc01.tar	2014-10-15 08:36:22 -05:00
Glenn Randers-Pehrson	6cae24c265	[libpng16] Fixed some typos in comments.	2014-10-13 11:11:21 -05:00
Glenn Randers-Pehrson	06ec570881	[libpng16] Bump version to 1.6.14beta08	2014-10-07 18:57:36 -05:00
Glenn Randers-Pehrson	25d240dc6e	[libpng16] Imported from libpng-1.6.14beta07.tar	2014-10-07 18:57:21 -05:00
Glenn Randers-Pehrson	470d64c2dd	[libpng16] Also don't mark text as written in the end_ptr until written.	2014-10-05 18:08:39 -05:00
Glenn Randers-Pehrson	d7eff5d864	[libpng16] Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa	2014-10-05 13:46:58 -05:00
Glenn Randers-Pehrson	a11cd84160	[libpng16] Only mark text chunks as written after successfully writing them.	2014-10-05 13:45:38 -05:00
Glenn Randers-Pehrson	f56c00f050	[libpng16] Bump version to 1.6.14beta07	2014-10-05 07:48:53 -05:00
Glenn Randers-Pehrson	f1a22bf9b3	[libpng16] Imported from libpng-1.6.14beta06.tar	2014-10-05 07:48:44 -05:00
Glenn Randers-Pehrson	a4fa1c57f4	[libpng16] Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT" to pnglibconf.dfa.	2014-10-04 12:38:47 -05:00
Glenn Randers-Pehrson	27f0332cae	[libpng16] Replaced repeated code with PNG_PUSH_SAVE_BUFFER_IF_FULL in pngpread.c	2014-10-04 10:28:58 -05:00
Glenn Randers-Pehrson	9127138a30	[libpng16] Fix typos in comments in pngset.c and pngtrans.c	2014-10-03 20:23:31 -05:00
Glenn Randers-Pehrson	ca9c3a601b	[libpng16] Edited comments in png.c	2014-10-03 18:08:34 -05:00
Glenn Randers-Pehrson	91e3a7d735	[libpng16] Edited some comments in pngwutil.c	2014-10-03 17:33:14 -05:00
Glenn Randers-Pehrson	cb4823d91f	[libpng16] Conditionally compile some code in png_deflate_claim(), when PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.	2014-10-03 17:14:39 -05:00
Glenn Randers-Pehrson	d752225d05	[libpng16] Removed "text_len" parameter from private function png_write_zTXt() since it is unused.	2014-10-03 17:11:50 -05:00
Glenn Randers-Pehrson	f1eacc08e6	[libpng16] Bump version to 1.6.14beta06	2014-10-01 10:46:37 -05:00
Glenn Randers-Pehrson	6147fae405	[libpng16] Imported from libpng-1.6.14beta05.tar	2014-10-01 10:46:29 -05:00
Glenn Randers-Pehrson	c5dc456afd	[libpng16] Redid recent changes to pnglibconf.h that were reverted.	2014-10-01 10:29:26 -05:00
Glenn Randers-Pehrson	f633a4eb9c	[libpng16] Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa	2014-10-01 10:03:57 -05:00
Glenn Randers-Pehrson	6c48f77bba	[libpng16] Merge pnglibconf.dfa with libpng-1.7.0beta37.	2014-09-28 13:43:28 -05:00
Glenn Randers-Pehrson	4c0ded3c4e	[libpng16] Bump version to 1.6.14beta05	2014-09-27 10:39:12 -05:00
Glenn Randers-Pehrson	36b246a571	[libpng16] Imported from libpng-1.6.14beta04.tar	2014-09-27 10:28:57 -05:00
Glenn Randers-Pehrson	48e6fad71c	[libpng16] Fixed incorrect handling of the iTXt compression flag in pngrutil.c (bug report by Shunsaku Hirata). Bug was introduced in libpng-1.6.0.	2014-09-27 09:37:50 -05:00
Glenn Randers-Pehrson	1b3a9fd6bf	[libpng16] Avoid defining simplified API macros in png.h when neither the READ nor the WRITE simplified API is supported.	2014-09-20 11:01:20 -05:00
Glenn Randers-Pehrson	b4ef94559d	[libpng16] Bump version to 1.6.14beta04	2014-09-19 07:58:07 -05:00
Glenn Randers-Pehrson	af557d98e1	[libpng16] Imported from libpng-1.6.14beta03.tar	2014-09-19 07:58:00 -05:00
Glenn Randers-Pehrson	551019baf6	[libpng16] Revert recent pngvalid.c changes and define FE_DIVBYZERO, etc., if not already defined.	2014-09-18 16:41:40 -05:00
Glenn Randers-Pehrson	77145bf678	[libpng16] Bump version to 1.6.14beta03	2014-09-18 09:56:47 -05:00
Glenn Randers-Pehrson	91685564d1	[libpng16] Imported from libpng-1.6.14beta02.tar	2014-09-18 09:56:39 -05:00
Glenn Randers-Pehrson	44bda93154	[libpng16] Updated INSTALL info about pnglibconf.h	2014-09-18 09:27:29 -05:00
Glenn Randers-Pehrson	baa95a2d49	[libpng16] Do not include <fenv.h> when FLOATING_ARITHMETIC is not supported.	2014-09-18 09:23:45 -05:00
Glenn Randers-Pehrson	996046aed5	[libpng16] Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c because usleep() is deprecated.	2014-09-14 16:34:09 -05:00
Glenn Randers-Pehrson	e4489f1db2	[libpng16] Only define usleep() in gregbook/rpng2-x.c if not already defined.	2014-09-14 15:06:00 -05:00
Glenn Randers-Pehrson	3fe1616c45	[libpng16] Bump version to 1.6.14beta02	2014-09-14 14:23:40 -05:00
Glenn Randers-Pehrson	0df3198719	[libpng16] Imported from libpng-1.6.14beta01.tar	2014-09-14 14:23:32 -05:00
Glenn Randers-Pehrson	3a05d2df0f	[libpng16] Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)	2014-09-11 07:39:24 -05:00
Glenn Randers-Pehrson	de5e34f3ce	[libpng16] Add #include <setjmp.h> to contrib/tools/pngfix.c to allow "make" to complete without setjmp support (bug report by Claudio Fontana)	2014-09-10 21:34:34 -05:00
Glenn Randers-Pehrson	0a3c788b51	[libpng16] Don't build contrib/tools/pngfix.c without setjmp support.	2014-09-10 17:27:53 -05:00
Glenn Randers-Pehrson	664bd637b5	[libpng16] Fixed some indentation in pngrutil.c	2014-08-26 19:55:58 -05:00
Glenn Randers-Pehrson	3669467347	[libpng16] Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.	2014-08-22 08:55:50 -05:00
Glenn Randers-Pehrson	bcd3209a42	[libpng16] Update last-changed date	2014-08-21 09:57:23 -05:00
Glenn Randers-Pehrson	17fba0f7d1	[libpng16] Bump version to 1.6.14beta01	2014-08-21 09:16:02 -05:00