[libpng16] Imported from libpng-1.6.17beta06.tar

2025-07-10 18:04:09 +02:00 · 2015-02-27 18:55:51 -06:00
45 changed files with 400 additions and 478 deletions
--- a/54
+++ b/54
@@ -1,4 +1,4 @@
-Libpng 1.6.17rc06 - March 23, 2015
+Libpng 1.6.17beta06 - February 28, 2015

 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.
@@ -8,20 +8,20 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.6.17rc06.tar.xz (LZMA-compressed, recommended)
-   1.6.17rc06.tar.gz
+   1.6.17beta06.tar.xz (LZMA-compressed, recommended)
+   1.6.17beta06.tar.gz

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

-   lp1617r06.7z  (LZMA-compressed, recommended)
-   lp1617r06.zip
+   lp1617b06.7z  (LZMA-compressed, recommended)
+   lp1617b06.zip

 Other information:

-   1.6.17rc06-README.txt
-   1.6.17rc06-LICENSE.txt
-   libpng-1.6.17rc06-*.asc (armored detached GPG signatures)
+   1.6.17beta06-README.txt
+   1.6.17beta06-LICENSE.txt
+   libpng-1.6.17beta06-*.asc (armored detached GPG signatures)

 Changes since the last public release (1.6.16):

@@ -39,8 +39,6 @@ Version 1.6.17beta01 [January 29, 2015]
  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
    pngset.c to avoid warnings about dead code.
-  Added "& 0xff" to many instances of expressions that are typecast
-    to (png_byte), to avoid Coverity gripes.

 Version 1.6.17beta02 [February 7, 2015]
  Work around one more Coverity-scan dead-code warning.
@@ -61,46 +59,12 @@ Version 1.6.17beta04 [February 21, 2015]
 Version 1.6.17beta05 [February 25, 2015]
  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.

-Version 1.6.17beta06 [February 27, 2015]
+Version 1.6.17beta06 [February 28, 2015]
  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
    of png.h.
  Avoid runtime checks when converting integer to png_byte with
    Visual Studio (Sergey Kosarevsky)

-Version 1.6.17rc01 [March 4, 2015]
-  No changes.
-
-Version 1.6.17rc02 [March 9, 2015]
-  Removed some comments that the configure script did not handle
-    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
-  Free the unknown_chunks structure even when it contains no data.
-
-Version 1.6.17rc03 [March 12, 2015]
-  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
-    for consistency, and remove some useless tests (Alexey Petruchik).
-
-Version 1.6.17rc04 [March 16, 2015]
-  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
-    pnglibconf.* in "make clean" (Cosmin).
-  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
-    in libpng-1.6.17beta01 (John Bowler).
-
-Version 1.6.17rc05 [March 21, 2015]
-  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
-    is not supported (John Bowler).  This fixes an error introduced in
-    libpng-1.6.17beta06.
-  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
-    the Coverity scan without them.
-
-Version 1.6.17rc06 [March 23, 2015]
-  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
-  Reformatted some "&0xff" instances to "& 0xff".
-  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
-    value was wrong.  It's not clear if this affected the final stored
-    value; in the obvious code path the upper and lower 8-bits of the
-    alpha value were identical and the alpha was truncated to 8-bits
-    rather than dividing by 257 (John Bowler).
-
 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/40
+++ b/40
@@ -2102,7 +2102,7 @@ Version 1.4.0beta24 [July 25, 2008]
    png_decompress_chunk(), and remove "chunkdata" from parameter list.
  Put a call to png_check_chunk_name() in png_read_chunk_header().
  Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
-  Removed two calls to png_check_chunk_name() occurring later in the process.
+  Removed two calls to png_check_chunk_name() occuring later in the process.
  Define PNG_NO_ERROR_NUMBERS by default in pngconf.h

 Version 1.4.0beta25 [July 30, 2008]
@@ -5140,8 +5140,6 @@ Version 1.6.17beta01 [January 29, 2015]
  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
    pngset.c to avoid warnings about dead code.
-  Added "& 0xff" to many instances of expressions that are typecast
-    to (png_byte), to avoid Coverity gripes.

 Version 1.6.17beta02 [February 7, 2015]
  Work around one more Coverity-scan dead-code warning.
@@ -5162,46 +5160,12 @@ Version 1.6.17beta04 [February 21, 2015]
 Version 1.6.17beta05 [February 25, 2015]
  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.

-Version 1.6.17beta06 [February 27, 2015]
+Version 1.6.17beta06 [February 28, 2015]
  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
    of png.h.
  Avoid runtime checks when converting integer to png_byte with
    Visual Studio (Sergey Kosarevsky)

-Version 1.6.17rc01 [March 4, 2015]
-  No changes.
-
-Version 1.6.17rc02 [March 9, 2015]
-  Removed some comments that the configure script did not handle
-    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
-  Free the unknown_chunks structure even when it contains no data.
-
-Version 1.6.17rc03 [March 12, 2015]
-  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
-    for consistency, and remove some useless tests (Alexey Petruchik).
-
-Version 1.6.17rc04 [March 16, 2015]
-  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
-    pnglibconf.* in "make clean" (Cosmin).
-  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
-    in libpng-1.6.17beta01 (John Bowler).
-
-Version 1.6.17rc05 [March 21, 2015]
-  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
-    is not supported (John Bowler).  This fixes an error introduced in
-    libpng-1.6.17beta06.
-  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
-    the Coverity scan without them.
-
-Version 1.6.17rc06 [March 23, 2015]
-  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
-  Reformatted some "&0xff" instances to "& 0xff".
-  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
-    value was wrong.  It's not clear if this affected the final stored
-    value; in the obvious code path the upper and lower 8-bits of the
-    alpha value were identical and the alpha was truncated to 8-bits
-    rather than dividing by 257 (John Bowler).
-
 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
@@ -1,6 +1,6 @@
 # CMakeLists.txt

-# Copyright (C) 2007-2015 Glenn Randers-Pehrson
+# Copyright (C) 2007-2014 Glenn Randers-Pehrson

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -30,7 +30,8 @@ if(NOT WIN32)
    PATHS /usr/lib /usr/local/lib
  )
  if(NOT M_LIBRARY)
-    message(STATUS "math lib 'libm' not found; floating point support disabled")
+    message(STATUS
+      "math library 'libm' not found - floating point support disabled")
  endif()
 else()
  # not needed on windows
@@ -38,14 +39,22 @@ else()
 endif()

 # COMMAND LINE OPTIONS
-option(PNG_SHARED "Build shared lib" ON)
-option(PNG_STATIC "Build static lib" ON)
-option(PNG_TESTS  "Build libpng tests" ON)
+if(DEFINED PNG_SHARED)
+  option(PNG_SHARED "Build shared lib" ${PNG_SHARED})
+else()
+  option(PNG_SHARED "Build shared lib" ON)
+endif()
+if(DEFINED PNG_STATIC)
+  option(PNG_STATIC "Build static lib" ${PNG_STATIC})
+else()
+  option(PNG_STATIC "Build static lib" ON)
+endif()
+
+option(PNG_TESTS  "Build libpng tests" YES)

 # Many more configuration options could be added here
-option(PNG_FRAMEWORK "Build OS X framework" OFF)
-option(PNG_DEBUG     "Build with debug output" OFF)
-option(PNGARG        "Disable ANSI-C prototypes" OFF)
+option(PNG_DEBUG         "Build with debug output" NO)
+option(PNGARG            "Disable ANSI-C prototypes" NO)

 # SET LIBNAME
 set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
@@ -125,7 +134,7 @@ if(PNG_SHARED)
 endif()

 if(PNG_STATIC)
-  # does not work without changing name
+# does not work without changing name
  set(PNG_LIB_NAME_STATIC ${PNG_LIB_NAME}_static)
  add_library(${PNG_LIB_NAME_STATIC} STATIC ${libpng_sources})
  list(APPEND PNG_LIB_TARGETS ${PNG_LIB_NAME_STATIC})
@@ -136,27 +145,10 @@ if(PNG_STATIC)
  target_link_libraries(${PNG_LIB_NAME_STATIC} ${ZLIB_LIBRARY} ${M_LIBRARY})
 endif()

-if(PNG_FRAMEWORK)
-  set(PNG_LIB_NAME_FRAMEWORK ${PNG_LIB_NAME}_framework)
-  add_library(${PNG_LIB_NAME_FRAMEWORK} SHARED ${libpng_sources})
-  list(APPEND PNG_LIB_TARGETS ${PNG_LIB_NAME_FRAMEWORK})
-  set_target_properties(${PNG_LIB_NAME_FRAMEWORK} PROPERTIES
-    FRAMEWORK TRUE
-    FRAMEWORK_VERSION ${PNGLIB_VERSION}
-    MACOSX_FRAMEWORK_SHORT_VERSION_STRING ${PNGLIB_MAJOR}.${PNGLIB_MINOR}
-    MACOSX_FRAMEWORK_BUNDLE_VERSION ${PNGLIB_VERSION}
-    MACOSX_FRAMEWORK_IDENTIFIER org.libpng.libpng
-    XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
-    PUBLIC_HEADER "${libpng_public_hdrs}"
-    OUTPUT_NAME png)
-  target_link_libraries(${PNG_LIB_NAME_FRAMEWORK} ${ZLIB_LIBRARY} ${M_LIBRARY})
-endif()
-
 if(NOT PNG_LIB_TARGETS)
  message(SEND_ERROR
    "No library variant selected to build. "
-    "Please enable at least one of the following options: "
-    " PNG_STATIC, PNG_SHARED, PNG_FRAMEWORK")
+    "Please enable at least one of the following options: PNG_STATIC, PNG_SHARED")
 endif()

 if(PNG_SHARED AND WIN32)
@@ -261,7 +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}.1.6.17rc06
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.17beta06
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
@@ -292,8 +284,7 @@ if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
      ${PNG_EXPORT_RULE}
      RUNTIME DESTINATION bin
      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-      FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
+      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})

  if(PNG_SHARED)
    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
--- a/2
+++ b/2
@@ -189,7 +189,7 @@ run "make install".
 VIII. Configuring libpng for 16-bit platforms

 You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more than 64K at a time.  Even if you can, the memory
+it cannot allocate more then 64K at a time.  Even if you can, the memory
 won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.

 IX. Configuring for DOS
--- 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 1.6.17rc06, March 23, 2015, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.17beta06, February 28, 2015, are
 Copyright (c) 2004, 2006-2015 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
-March 23, 2015
+February 28, 2015
--- a/Makefile.am
+++ b/Makefile.am
@@ -129,12 +129,11 @@ EXTRA_DIST= \
 	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
 	CMakeLists.txt example.c libpng-manual.txt

-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.c

 CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
 	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
-	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
-	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
+	check.new pnglibconf.* pngprefix.h symbols.new pngtest-log.txt \
 	$(SCRIPT_CLEANFILES)

 MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-README for libpng version 1.6.17rc06 - March 23, 2015 (shared library 16.0)
+README for libpng version 1.6.17beta06 - February 28, 2015 (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.
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.17rc06],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.17beta06],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -39,7 +39,7 @@ 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=1.6.17rc06
+PNGLIB_VERSION=1.6.17beta06
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
 PNGLIB_RELEASE=17
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
@@ -1242,4 +1242,4 @@ main(void)
   /* So the test is skipped: */
   return 77;
 }
-#endif /* SET_UNKNOWN_CHUNKS && READ */
+#endif /* SET_UNKNOWN_CHUNKS && READ*/
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -2138,7 +2138,7 @@ zlib_end(struct zlib *zlib)
          *
          * z-rc is the zlib failure code; message is the error message with
          * spaces replaced by '-'.  The compressed byte count indicates where
-          * in the zlib stream the error occurred.
+          * in the zlib stream the error occured.
          */
         type_name(zlib->chunk->chunk_type, stdout);
         printf(" SKP %s %d %s ", zlib_flevel(zlib), zlib->file_bits,
@@ -3757,7 +3757,7 @@ usage(const char *prog)
 "  non-zero code is returned).",
 "    0x10: The file could not be read, even with corrections.",
 "    0x20: The output file could not be written.",
-"    0x40: An unexpected, potentially internal, error occurred.",
+"    0x40: An unexpected, potentially internal, error occured.",
 "  If the command line arguments are incorrect the program exits with exit",
 "  255.  Some older operating systems only support 7-bit exit codes, on those",
 "  systems it is suggested that this program is first tested by supplying",
--- 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 1.6.17rc06 - March 23, 2015
+ libpng version 1.6.17beta06 - February 28, 2015
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2015 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 1.6.17rc06 - March 23, 2015
+ libpng versions 0.97, January 1998, through 1.6.17beta06 - February 28, 2015
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2015 Glenn Randers-Pehrson

@@ -336,7 +336,7 @@ prediction.

 If you are intending to keep the file pointer open for use in libpng,
 you must ensure you don't read more than 8 bytes from the beginning
-of the file, and you also have to make a call to png_set_sig_bytes()
+of the file, and you also have to make a call to png_set_sig_bytes_read()
 with the number of bytes you read from the beginning.  Libpng will
 then only check the bytes (if any) that your program didn't read.

@@ -1994,7 +1994,7 @@ value when you call it in this position:
      png_set_gamma(png_ptr, screen_gamma, 0.45455);

 If you need to reduce an RGB file to a paletted file, or if a paletted
-file has more entries than will fit on your screen, png_set_quantize()
+file has more entries then will fit on your screen, png_set_quantize()
 will do that.  Note that this is a simple match quantization that merely
 finds the closest color available.  This should work fairly well with
 optimized palettes, but fairly badly with linear color cubes.  If you
@@ -2547,7 +2547,7 @@ png_infop info_ptr;
       64K.  The library seems to run fine with sizes
       of 4K. Although you can give it much less if
       necessary (I assume you can give it chunks of
-       1 byte, I haven't tried less than 256 bytes
+       1 byte, I haven't tried less then 256 bytes
       yet).  When this function returns, you may
       want to display any rows that were generated
       in the row callback if you don't already do
@@ -5032,10 +5032,6 @@ The signatures of many exported functions were changed, such that
   png_infop became png_inforp or png_const_inforp
 where "rp" indicates a "restricted pointer".

-The support for FAR/far types has been eliminated and the definition of
-png_alloc_size_t is now controlled by a flag so that 'small size_t' systems
-can select it if necessary.
-
 Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
@@ -5279,13 +5275,13 @@ Other rules can be inferred by inspecting the libpng source.

 XVI. Y2K Compliance in libpng

-March 23, 2015
+February 28, 2015

 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 1.6.17rc06 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.17beta06 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
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "March 23, 2015"
+.TH LIBPNG 3 "February 28, 2015"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17rc06
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17beta06
 .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 1.6.17rc06 - March 23, 2015
+ libpng version 1.6.17beta06 - February 28, 2015
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2015 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 1.6.17rc06 - March 23, 2015
+ libpng versions 0.97, January 1998, through 1.6.17beta06 - February 28, 2015
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2015 Glenn Randers-Pehrson

@@ -840,7 +840,7 @@ prediction.

 If you are intending to keep the file pointer open for use in libpng,
 you must ensure you don't read more than 8 bytes from the beginning
-of the file, and you also have to make a call to png_set_sig_bytes()
+of the file, and you also have to make a call to png_set_sig_bytes_read()
 with the number of bytes you read from the beginning.  Libpng will
 then only check the bytes (if any) that your program didn't read.

@@ -2498,7 +2498,7 @@ value when you call it in this position:
      png_set_gamma(png_ptr, screen_gamma, 0.45455);

 If you need to reduce an RGB file to a paletted file, or if a paletted
-file has more entries than will fit on your screen, png_set_quantize()
+file has more entries then will fit on your screen, png_set_quantize()
 will do that.  Note that this is a simple match quantization that merely
 finds the closest color available.  This should work fairly well with
 optimized palettes, but fairly badly with linear color cubes.  If you
@@ -3051,7 +3051,7 @@ png_infop info_ptr;
       64K.  The library seems to run fine with sizes
       of 4K. Although you can give it much less if
       necessary (I assume you can give it chunks of
-       1 byte, I haven't tried less than 256 bytes
+       1 byte, I haven't tried less then 256 bytes
       yet).  When this function returns, you may
       want to display any rows that were generated
       in the row callback if you don't already do
@@ -5536,10 +5536,6 @@ The signatures of many exported functions were changed, such that
   png_infop became png_inforp or png_const_inforp
 where "rp" indicates a "restricted pointer".

-The support for FAR/far types has been eliminated and the definition of
-png_alloc_size_t is now controlled by a flag so that 'small size_t' systems
-can select it if necessary.
-
 Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
@@ -5783,13 +5779,13 @@ Other rules can be inferred by inspecting the libpng source.

 .SH XVI. Y2K Compliance in libpng

-March 23, 2015
+February 28, 2015

 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 1.6.17rc06 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.17beta06 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
@@ -6042,7 +6038,6 @@ the first widely used release:
 1.6.16rc01-02       16    10616  16.so.16.16[.0]
 1.6.16              16    10616  16.so.16.16[.0]
 1.6.17beta01-06     16    10617  16.so.16.17[.0]
- 1.6.17rc01-06       16    10617  16.so.16.17[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6099,7 +6094,7 @@ possible without all of you.

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

-Libpng version 1.6.17rc06 - March 23, 2015:
+Libpng version 1.6.17beta06 - February 28, 2015:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6122,8 +6117,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.17rc06, March 23, 2015, are
-Copyright (c) 2004,2006-2015 Glenn Randers-Pehrson, and are
+libpng versions 1.2.6, August 15, 2004, through 1.6.17beta06, February 28, 2015, 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

@@ -6221,7 +6216,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-March 23, 2015
+February 28, 2015

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "March 23, 2015"
+.TH LIBPNGPF 3 "February 28, 2015"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17rc06
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17beta06
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "March 23, 2015"
+.TH PNG 5 "February 28, 2015"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
--- a/png.c
+++ b/png.c
@@ -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_17rc06 Your_png_h_is_not_version_1_6_17rc06;
+typedef png_libpng_version_1_6_17beta06 Your_png_h_is_not_version_1_6_17beta06;

 /* 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
@@ -547,17 +547,20 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

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

-         png_free(png_ptr, info_ptr->splt_palettes);
-         info_ptr->splt_palettes = NULL;
-         info_ptr->splt_palettes_num = 0;
+            for (i = 0; i < info_ptr->splt_palettes_num; 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;
+            info_ptr->splt_palettes_num = 0;
+         }
         info_ptr->valid &= ~PNG_INFO_sPLT;
      }
   }
@@ -577,12 +580,15 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
      {
         int i;

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

-         png_free(png_ptr, info_ptr->unknown_chunks);
-         info_ptr->unknown_chunks = NULL;
-         info_ptr->unknown_chunks_num = 0;
+            png_free(png_ptr, info_ptr->unknown_chunks);
+            info_ptr->unknown_chunks = NULL;
+            info_ptr->unknown_chunks_num = 0;
+         }
      }
   }
 #endif
@@ -766,13 +772,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-     "libpng version 1.6.17rc06 - March 23, 2015" PNG_STRING_NEWLINE \
+     "libpng version 1.6.17beta06 - February 28, 2015" PNG_STRING_NEWLINE \
     "Copyright (c) 1998-2015 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 1.6.17rc06 - March 23, 2015\
+      return "libpng version 1.6.17beta06 - February 28, 2015\
      Copyright (c) 1998-2015 Glenn Randers-Pehrson\
      Copyright (c) 1996-1997 Andreas Dilger\
      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -3034,7 +3040,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
            /* Check for an exponent, if we don't need one we are
             * done and just need to terminate the string.  At
             * this point exp_b10==(-1) is effectively if flag - it got
-             * to '-1' because of the decrement after outputting
+             * to '-1' because of the decrement after outputing
             * the decimal point above (the exponent required is
             * *not* -1!)
             */
@@ -3042,7 +3048,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
            {
               /* The following only happens if we didn't output the
                * leading zeros above for negative exponent, so this
-                * doesn't add to the digit requirement.  Note that the
+                * doest add to the digit requirement.  Note that the
                * two zeros here can only be output if the two leading
                * zeros were *not* output, so this doesn't increase
                * the output count.
--- a/png.h
+++ b/png.h
@@ -1,8 +1,7 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.17rc06, March 23, 2015
- *
+ * libpng version 1.6.17beta06, February 28, 2015
 * Copyright (c) 1998-2015 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.)
@@ -12,7 +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 1.6.17rc06, March 23, 2015: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.17beta06, February 28, 2015: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -214,7 +213,6 @@
 *    1.6.16rc01-02           16    10616  16.so.16.16[.0]
 *    1.6.16                  16    10616  16.so.16.16[.0]
 *    1.6.17beta01-06         16    10617  16.so.16.17[.0]
- *    1.6.17rc01-06           16    10617  16.so.16.17[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -246,7 +244,7 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.17rc06, March 23, 2015, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.17beta06, February 28, 2015, are
 * Copyright (c) 2004, 2006-2015 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:
@@ -358,13 +356,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    March 23, 2015
+ *    February 28, 2015
 *
 *    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 1.6.17rc06 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.17beta06 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
@@ -426,9 +424,9 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.17rc06"
+#define PNG_LIBPNG_VER_STRING "1.6.17beta06"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.17rc06 - March 23, 2015\n"
+     " libpng version 1.6.17beta06 - February 28, 2015\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -459,7 +457,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_RC
+#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.
@@ -572,7 +570,7 @@ 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_17rc06;
+typedef char* png_libpng_version_1_6_17beta06;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -1595,7 +1593,6 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
 */
 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
    int filters));
-#endif /* WRITE */

 /* Flags for png_set_filter() to say which filters to use.  The flags
 * are chosen so that they don't conflict with real filter types
@@ -1621,7 +1618,6 @@ PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
 #define PNG_FILTER_VALUE_PAETH 4
 #define PNG_FILTER_VALUE_LAST  5

-#ifdef PNG_WRITE_SUPPORTED
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
 * defines, either the default (minimum-sum-of-absolute-differences), or
@@ -1826,7 +1822,7 @@ PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
 *
 * The integer return from the callback function is interpreted thus:
 *
- * negative: An error occurred; png_chunk_error will be called.
+ * negative: An error occured, png_chunk_error will be called.
 *     zero: The chunk was not handled, the chunk will be saved. A critical
 *           chunk will cause an error at this point unless it is to be saved.
 * positive: The chunk was handled, libpng will ignore/discard it.
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.17rc06, (PENDING RELEASE)
+ * libpng version 1.6.17beta06, (PENDING RELEASE)
 *
 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -11,7 +11,9 @@
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 *
- * Any machine specific code is near the front of this file, so if you
+ */
+
+/* Any machine specific code is near the front of this file, so if you
 * are configuring libpng for a machine, you may want to read the section
 * starting here down to where it starts to typedef png_color, png_text,
 * and png_info.
--- a/pngget.c
+++ b/pngget.c
@@ -1123,7 +1123,7 @@ png_get_unknown_chunks(png_const_structrp png_ptr, png_inforp info_ptr,
 png_byte PNGAPI
 png_get_rgb_to_gray_status (png_const_structrp png_ptr)
 {
-   return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0);
+   return (png_byte)((png_ptr ? png_ptr->rgb_to_gray_status : 0) & 0xff);
 }
 #endif

--- a/pngmem.c
+++ b/pngmem.c
@@ -41,7 +41,7 @@ png_destroy_png_struct(png_structrp png_ptr)
 }

 /* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * 64K.  However, zlib may allocate more then 64K if you don't tell
 * it not to.  See zconf.h and png.h for more information.  zlib does
 * need to allocate exactly 64K, so whatever you call here must
 * have the ability to do that.
--- a/pngpread.c
+++ b/pngpread.c
@@ -168,7 +168,7 @@ png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)

   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
       num_to_check);
-   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
+   png_ptr->sig_bytes = (png_byte)((png_ptr->sig_bytes + num_to_check) & 0xff);

   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
   {
--- a/pngread.c
+++ b/pngread.c
@@ -1823,7 +1823,6 @@ png_create_colormap_entry(png_image_read_control *display,
            y = (y + 128) >> 8;
            y *= 255;
            y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
-            alpha = PNG_DIV257(alpha);
            encoding = P_sRGB;
         }

@@ -2053,7 +2052,7 @@ make_rgb_colormap(png_image_read_control *display)

 /* Return a palette index to the above palette given three 8-bit sRGB values. */
 #define PNG_RGB_INDEX(r,g,b) \
-   ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
+   ((png_byte)(0xff & (6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b))))

 static int
 png_image_read_colormap(png_voidp argument)
@@ -3026,7 +3025,8 @@ png_image_read_and_map(png_voidp argument)
                        *outrow = gray;

                     else
-                        *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
+                        *outrow =
+                            (png_byte)(0xff & (PNG_CMAP_TRANS_BACKGROUND+1));
                  }
                  break;

--- a/pngrio.c
+++ b/pngrio.c
@@ -26,7 +26,7 @@
 * reads from a file pointer.  Note that this routine sometimes gets called
 * with very small lengths, so you should implement some kind of simple
 * buffering if you are using unbuffered reads.  This should never be asked
- * to read more than 64K on a 16 bit machine.
+ * to read more then 64K on a 16 bit machine.
 */
 void /* PRIVATE */
 png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -143,7 +143,7 @@ png_set_background_fixed(png_structrp png_ptr,

   png_ptr->background = *background_color;
   png_ptr->background_gamma = background_gamma;
-   png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
+   png_ptr->background_gamma_type = (png_byte)(0xff & background_gamma_code);
   if (need_expand != 0)
      png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
   else
@@ -394,7 +394,7 @@ png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
 /* Dither file to 8-bit.  Supply a palette, the current number
 * of elements in the palette, the maximum number of elements
 * allowed, and a histogram if possible.  If the current number
- * of colors is greater than the maximum number, the palette will be
+ * of colors is greater then the maximum number, the palette will be
 * modified to fit in the maximum number.  "full_quantize" indicates
 * whether we need a quantizing cube set up for RGB images, or if we
 * simply are reducing the number of colors in a paletted image.
@@ -1176,8 +1176,8 @@ png_init_palette_transformations(png_structrp png_ptr)
              int i, istop = png_ptr->num_trans;

              for (i=0; i<istop; i++)
-                 png_ptr->trans_alpha[i] = (png_byte)(255 -
-                    png_ptr->trans_alpha[i]);
+                 png_ptr->trans_alpha[i] = (png_byte)(0xff & (255 -
+                    png_ptr->trans_alpha[i]));
           }
        }
 #endif /* READ_INVERT_ALPHA */
@@ -2023,14 +2023,14 @@ 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) != 0)
-      info_ptr->color_type = (png_byte)(info_ptr->color_type |
-         PNG_COLOR_MASK_COLOR);
+      info_ptr->color_type = (png_byte)(0xff & (info_ptr->color_type |
+         PNG_COLOR_MASK_COLOR));
 #endif

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

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
@@ -2072,8 +2072,8 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
   {
-      info_ptr->color_type = (png_byte)(info_ptr->color_type &
-         ~PNG_COLOR_MASK_ALPHA);
+      info_ptr->color_type = (png_byte)(0xff & (info_ptr->color_type &
+         ~PNG_COLOR_MASK_ALPHA));
      info_ptr->num_trans = 0;
   }
 #endif
@@ -2106,8 +2106,8 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
   }
 #endif

-   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
-       info_ptr->bit_depth);
+   info_ptr->pixel_depth = (png_byte)(0xff & (info_ptr->channels *
+       info_ptr->bit_depth));

   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);

@@ -2218,7 +2218,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
            break;
      }
      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->pixel_depth = (png_byte)(0xff & (8 * row_info->channels));
      row_info->rowbytes = row_width * row_info->channels;
   }
 }
@@ -2356,8 +2356,8 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
               value >>= shift[channel];
               if (++channel >= channels)
                  channel = 0;
-               *bp++ = (png_byte)(value >> 8);
-               *bp++ = (png_byte)value;
+               *bp++ = (png_byte)(0xff & (value >> 8));
+               *bp++ = (png_byte)(0xff & value);
            }
            break;
         }
@@ -2420,7 +2420,7 @@ png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
      }

      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->pixel_depth = (png_byte)(0xff & (8 * row_info->channels));
      row_info->rowbytes = row_info->width * row_info->channels;
   }
 }
@@ -2448,7 +2448,7 @@ png_do_chop(png_row_infop row_info, png_bytep row)
      }

      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->pixel_depth = (png_byte)(0xff & (8 * row_info->channels));
      row_info->rowbytes = row_info->width * row_info->channels;
   }
 }
@@ -2570,7 +2570,7 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)

         for (i = 0; i < row_width; i++)
         {
-            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));

 /*          This does nothing:
            *(--dp) = *(--sp);
@@ -2593,8 +2593,8 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)

         for (i = 0; i < row_width; i++)
         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));

 /*          This does nothing:
            *(--dp) = *(--sp);
@@ -2622,7 +2622,7 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)

         for (i = 0; i < row_width; i++)
         {
-            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));
            *(--dp) = *(--sp);
         }
      }
@@ -2637,8 +2637,8 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)

         for (i = 0; i < row_width; i++)
         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));
+            *(--dp) = (png_byte)(0xff & (255 - *(--sp)));
 /*
            *(--dp) = *(--sp);
            *(--dp) = *(--sp);
@@ -2662,9 +2662,9 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
   png_uint_32 row_width = row_info->width;

 #ifdef PNG_READ_16BIT_SUPPORTED
-   png_byte hi_filler = (png_byte)(filler>>8);
+   png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
 #endif
-   png_byte lo_filler = (png_byte)filler;
+   png_byte lo_filler = (png_byte)(filler & 0xff);

   png_debug(1, "in png_do_read_filler");

@@ -2918,10 +2918,10 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
            }
         }
      }
-      row_info->channels = (png_byte)(row_info->channels + 2);
+      row_info->channels = (png_byte)(0xff & (row_info->channels + 2));
      row_info->color_type |= PNG_COLOR_MASK_COLOR;
-      row_info->pixel_depth = (png_byte)(row_info->channels *
-          row_info->bit_depth);
+      row_info->pixel_depth = (png_byte)(0xff & (row_info->channels *
+          row_info->bit_depth));
      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
   }
 }
@@ -3063,7 +3063,8 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
                  /* NOTE: this is the historical approach which simply
                   * truncates the results.
                   */
-                  *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) =
+                      (png_byte)(0xff & ((rc*red + gc*green + bc*blue)>>15));
               }

               else
@@ -3105,16 +3106,16 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)

               else
               {
-                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red & 0xff)
+                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff)
                      >> png_ptr->gamma_shift][red>>8];
                  png_uint_16 green_1 =
-                      png_ptr->gamma_16_to_1[(green & 0xff) >>
+                      png_ptr->gamma_16_to_1[(green&0xff) >>
                      png_ptr->gamma_shift][green>>8];
-                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue & 0xff)
+                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff)
                      >> png_ptr->gamma_shift][blue>>8];
                  png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
                      + bc*blue_1 + 16384)>>15);
-                  w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
+                  w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
                      png_ptr->gamma_shift][gray16 >> 8];
                  rgb_error |= 1;
               }
@@ -3166,11 +3167,11 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
         }
      }

-      row_info->channels = (png_byte)(row_info->channels - 2);
-      row_info->color_type = (png_byte)(row_info->color_type &
-          ~PNG_COLOR_MASK_COLOR);
-      row_info->pixel_depth = (png_byte)(row_info->channels *
-          row_info->bit_depth);
+      row_info->channels = (png_byte)(0xff & (row_info->channels - 2));
+      row_info->color_type = (png_byte)(0xff & (row_info->color_type &
+          ~PNG_COLOR_MASK_COLOR));
+      row_info->pixel_depth = (png_byte)(0xff & (row_info->channels *
+          row_info->bit_depth));
      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
   }
   return rgb_error;
@@ -3412,10 +3413,10 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                        if (v == png_ptr->trans_color.gray)
                        {
                           /* Background is already in screen gamma */
-                           *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray
-                                & 0xff);
+                           *sp = (png_byte)(0xff &
+                                (png_ptr->background.gray >> 8));
+                           *(sp + 1) = (png_byte)(0xff &
+                                png_ptr->background.gray);
                        }

                        else
@@ -3438,10 +3439,10 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)

                        if (v == png_ptr->trans_color.gray)
                        {
-                           *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray
-                                & 0xff);
+                           *sp = (png_byte)(0xff &
+                               (png_ptr->background.gray >> 8));
+                           *(sp + 1) = (png_byte)(0xff &
+                                png_ptr->background.gray);
                        }
                     }
                  }
@@ -3519,15 +3520,18 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         b == png_ptr->trans_color.blue)
                     {
                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                        *sp = (png_byte)(0xff &
+                            (png_ptr->background.red >> 8));
+                        *(sp + 1) = (png_byte)(0xff &
+                            png_ptr->background.red);
+                        *(sp + 2) = (png_byte)(0xff &
+                            (png_ptr->background.green >> 8));
+                        *(sp + 3) = (png_byte)(0xff &
+                            png_ptr->background.green);
+                        *(sp + 4) = (png_byte)(0xff &
+                            (png_ptr->background.blue >> 8));
+                        *(sp + 5) = (png_byte)(0xff &
+                            png_ptr->background.blue);
                     }

                     else
@@ -3565,15 +3569,15 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         g == png_ptr->trans_color.green &&
                         b == png_ptr->trans_color.blue)
                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                        *sp = (png_byte)(0xff & (png_ptr->background.red >> 8));
+                        *(sp + 1) = (png_byte)(0xff & png_ptr->background.red);
+                        *(sp + 2) = (png_byte)(0xff &
+                            (png_ptr->background.green >> 8));
+                        *(sp + 3) = (png_byte)(0xff &
+                             png_ptr->background.green);
+                        *(sp + 4) = (png_byte)(0xff &
+                             (png_ptr->background.blue >> 8));
+                        *(sp + 5) = (png_byte)(0xff & png_ptr->background.blue);
                     }
                  }
               }
@@ -3655,9 +3659,9 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                     else if (a == 0)
                     {
                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                        *sp = (png_byte)(0xff &
+                            (png_ptr->background.gray >> 8));
+                        *(sp + 1) = (png_byte)(0xff & png_ptr->background.gray);
                     }

                     else
@@ -3669,8 +3673,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                        if (optimize != 0)
                           w = v;
                        else
-                           w = gamma_16_from_1[(v & 0xff) >>
-                               gamma_shift][v >> 8];
+                           w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
                        *sp = (png_byte)((w >> 8) & 0xff);
                        *(sp + 1) = (png_byte)(w & 0xff);
                     }
@@ -3687,9 +3690,9 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)

                     if (a == 0)
                     {
-                        *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                        *sp = (png_byte)(0xff &
+                            (png_ptr->background.gray >> 8));
+                        *(sp + 1) = (png_byte)(0xff & png_ptr->background.gray);
                     }

                     else if (a < 0xffff)
@@ -3816,15 +3819,15 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                     else if (a == 0)
                     {
                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                        *sp = (png_byte)(0xff & (png_ptr->background.red >> 8));
+                        *(sp + 1) = (png_byte)(0xff & png_ptr->background.red );
+                        *(sp + 2) = (png_byte)(0xff &
+                             (png_ptr->background.green >> 8));
+                        *(sp + 3) = (png_byte)(0xff &
+                                png_ptr->background.green);
+                        *(sp + 4) = (png_byte)(0xff &
+                               (png_ptr->background.blue >> 8));
+                        *(sp + 5) = (png_byte)(0xff & png_ptr->background.blue);
                     }

                     else
@@ -3834,15 +3837,15 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                        v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
                        png_composite_16(w, v, a, png_ptr->background_1.red);
                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
-                                8];
+                           w = gamma_16_from_1[((w & 0xff) >>
+                                gamma_shift)][w >> 8];
                        *sp = (png_byte)((w >> 8) & 0xff);
                        *(sp + 1) = (png_byte)(w & 0xff);

                        v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
                        png_composite_16(w, v, a, png_ptr->background_1.green);
                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
                                8];

                        *(sp + 2) = (png_byte)((w >> 8) & 0xff);
@@ -3851,7 +3854,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                        v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
                        png_composite_16(w, v, a, png_ptr->background_1.blue);
                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
                                8];

                        *(sp + 4) = (png_byte)((w >> 8) & 0xff);
@@ -3871,15 +3874,16 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)

                     if (a == 0)
                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                        *sp = (png_byte)(0xff & (png_ptr->background.red >> 8));
+                        *(sp + 1) = (png_byte)(0xff & png_ptr->background.red);
+                        *(sp + 2) = (png_byte)(0xff &
+                               (png_ptr->background.green >> 8));
+                        *(sp + 3) = (png_byte)(0xff &
+                                png_ptr->background.green);
+                        *(sp + 4) = (png_byte)(0xff &
+                                (png_ptr->background.blue >> 8));
+                        *(sp + 5) = (png_byte)(0xff &
+                                png_ptr->background.blue & 0xff);
                     }

                     else if (a < 0xffff)
@@ -4066,11 +4070,12 @@ png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                  int c = *sp & 0x0c;
                  int d = *sp & 0x03;

-                  *sp = (png_byte)(
-                      ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+                  *sp = (png_byte)(0xff &
+                      (((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])  ) & 0xc0)|
                      ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
                      ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
-                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) & 0xff))
+                      );
                  sp++;
               }
            }
@@ -4401,8 +4406,8 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                  for (i = 0; i < row_width; i++)
                  {
                     value = (*sp >> shift) & 0x03;
-                     *dp = (png_byte)(value | (value << 2) | (value << 4) |
-                        (value << 6));
+                     *dp = (png_byte)(0xff & (value | (value << 2) |
+                        (value << 4) | (value << 6)));
                     if (shift == 6)
                     {
                        shift = 0;
@@ -4426,7 +4431,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                  for (i = 0; i < row_width; i++)
                  {
                     value = (*sp >> shift) & 0x0f;
-                     *dp = (png_byte)(value | (value << 4));
+                     *dp = (png_byte)(0xff & (value | (value << 4)));
                     if (shift == 4)
                     {
                        shift = 0;
@@ -4497,7 +4502,8 @@ png_do_expand(png_row_infop row_info, png_bytep row,

            row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
            row_info->channels = 2;
-            row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+            row_info->pixel_depth =
+               (png_byte)(0xff & (row_info->bit_depth << 1));
            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
               row_width);
         }
@@ -4564,7 +4570,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
         }
         row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
         row_info->channels = 4;
-         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+         row_info->pixel_depth = (png_byte)(0xff & (row_info->bit_depth << 2));
         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
      }
   }
@@ -4597,7 +4603,7 @@ png_do_expand_16(png_row_infop row_info, png_bytep row)

      row_info->rowbytes *= 2;
      row_info->bit_depth = 16;
-      row_info->pixel_depth = (png_byte)(row_info->channels * 16);
+      row_info->pixel_depth = (png_byte)(0xff & (row_info->channels * 16));
   }
 }
 #endif
@@ -4985,8 +4991,8 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
      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 *
-          row_info->channels);
+      row_info->pixel_depth = (png_byte)(0xff & (row_info->bit_depth *
+          row_info->channels));

      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
   }
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -822,13 +822,13 @@ png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   /* Set internal variables */
   png_ptr->width = width;
   png_ptr->height = height;
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->interlaced = (png_byte)interlace_type;
-   png_ptr->color_type = (png_byte)color_type;
+   png_ptr->bit_depth = (png_byte)(bit_depth & 0xff);
+   png_ptr->interlaced = (png_byte)(interlace_type & 0xff);
+   png_ptr->color_type = (png_byte)(color_type & 0xff);
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_ptr->filter_type = (png_byte)filter_type;
+   png_ptr->filter_type = (png_byte)(filter_type & 0xff);
 #endif
-   png_ptr->compression_type = (png_byte)compression_type;
+   png_ptr->compression_type = (png_byte)(compression_type & 0xff);

   /* Find number of channels */
   switch (png_ptr->color_type)
@@ -853,7 +853,8 @@ png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   }

   /* Set up other useful info */
-   png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
+   png_ptr->pixel_depth =
+       (png_byte)(0xff & (png_ptr->bit_depth * png_ptr->channels));
   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
   png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
   png_debug1(3, "channels = %d", png_ptr->channels);
@@ -2731,7 +2732,8 @@ png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
      /* The following is safe because of the PNG_SIZE_MAX init above */
      png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
      /* 'mode' is a flag array, only the bottom four bits matter here */
-      png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
+      png_ptr->unknown_chunk.location =
+          (png_byte)(0xff & png_ptr->mode/*SAFE*/);

      if (length == 0)
         png_ptr->unknown_chunk.data = NULL;
@@ -2806,7 +2808,7 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
               &png_ptr->unknown_chunk);

            /* ret is:
-             * negative: An error occurred; png_chunk_error will be called.
+             * negative: An error occured, png_chunk_error will be called.
             *     zero: The chunk was not handled, the chunk will be discarded
             *           unless png_set_keep_unknown_chunks has been used to set
             *           a 'keep' behavior for this particular chunk, in which
@@ -3228,7 +3230,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
            if (m != 0) /* something to copy */
            {
               if (m != 0xff)
-                  *dp = (png_byte)((*dp & ~m) | (*sp & m));
+                  *dp = (png_byte)(((*dp & ~m) | (*sp & m)) & 0xff);
               else
                  *dp = *sp;
            }
@@ -3480,7 +3482,8 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)

   /* Restore the overwritten bits from the last byte if necessary. */
   if (end_ptr != NULL)
-      *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
+      *end_ptr =
+          (png_byte)(0xff & ((end_byte & end_mask) | (*end_ptr & ~end_mask)));
 }

 #ifdef PNG_READ_INTERLACING_SUPPORTED
@@ -3774,16 +3777,14 @@ png_read_filter_row_avg(png_row_infop row_info, png_bytep row,

   for (i = 0; i < bpp; i++)
   {
-      *rp = (png_byte)(((int)(*rp) +
-         ((int)(*pp++) / 2 )) & 0xff);
+      *rp = (png_byte)(((int)(*rp) + ((int)(*pp++) / 2 )) & 0xff);

      rp++;
   }

   for (i = 0; i < istop; i++)
   {
-      *rp = (png_byte)(((int)(*rp) +
-         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);

      rp++;
   }
@@ -3799,7 +3800,7 @@ png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
   /* First pixel/byte */
   c = *prev_row++;
   a = *row + c;
-   *row++ = (png_byte)a;
+   *row++ = (png_byte)(a & 0xff);

   /* Remainder */
   while (row < rp_end)
@@ -3833,7 +3834,7 @@ png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
       */
      c = b;
      a += *row;
-      *row++ = (png_byte)a;
+      *row++ = (png_byte)(a & 0xff);
   }
 }

@@ -3850,7 +3851,7 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
   while (row < rp_end)
   {
      int a = *row + *prev_row++;
-      *row++ = (png_byte)a;
+      *row++ = (png_byte)(a & 0xff);
   }

   /* Remainder */
@@ -3881,7 +3882,7 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
      if (pc < pa) a = c;

      a += *row;
-      *row++ = (png_byte)a;
+      *row++ = (png_byte)(a & 0xff);
   }
 }

@@ -4374,7 +4375,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   /* This value is stored in png_struct and double checked in the row read
    * code.
    */
-   png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
+   png_ptr->maximum_pixel_depth = (png_byte)(max_pixel_depth & 0xff);
   png_ptr->transformed_pixel_depth = 0; /* calculated on demand */

   /* Align the width on the next larger 8 pixels.  Mainly used
@@ -4446,8 +4447,11 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   png_debug1(3, "height = %u,", png_ptr->height);
   png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
   png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
-   png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
-   png_debug1(3, "irowbytes = %lu",
+   png_debug1(3, "row_bytes = %lu,", (unsigned long)row_bytes);
+   png_debug1(3, "png_ptr->rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
+   png_debug1(3, "png_ptr->info_rowbytes = %lu,",
+       (unsigned long)png_ptr->info_rowbytes);
+   png_debug1(3, "PNG_ROWBYTES = %lu",
       (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);

   /* The sequential reader needs a buffer for IDAT, but the progressive reader
--- a/pngset.c
+++ b/pngset.c
@@ -1254,7 +1254,8 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
         check_location(png_ptr, location);
   }
 }
-#endif /* STORE_UNKNOWN_CHUNKS */
+#endif
+

 #ifdef PNG_MNG_FEATURES_SUPPORTED
 png_uint_32 PNGAPI
--- a/pngtest.c
+++ b/pngtest.c
@@ -469,7 +469,7 @@ pngtest_error(png_structp png_ptr, png_const_charp message)
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG

 /* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * 64K.  However, zlib may allocate more then 64K if you don't tell
 * it not to.  See zconf.h and png.h for more information.  zlib does
 * need to allocate exactly 64K, so whatever you call here must
 * have the ability to do that.
@@ -2028,4 +2028,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_17rc06 Your_png_h_is_not_version_1_6_17rc06;
+typedef png_libpng_version_1_6_17beta06 Your_png_h_is_not_version_1_6_17beta06;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,8 +1,8 @@

 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 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.)
 *
@@ -273,7 +273,7 @@ png_do_invert(png_row_infop row_info, png_bytep row)

      for (i = 0; i < istop; i++)
      {
-         *rp = (png_byte)(~(*rp));
+         *rp = (png_byte)((~(*rp)) & 0xff);
         rp++;
      }
   }
@@ -287,7 +287,7 @@ png_do_invert(png_row_infop row_info, png_bytep row)

      for (i = 0; i < istop; i += 2)
      {
-         *rp = (png_byte)(~(*rp));
+         *rp = (png_byte)((~(*rp)) & 0xff);
         rp += 2;
      }
   }
@@ -302,8 +302,8 @@ png_do_invert(png_row_infop row_info, png_bytep row)

      for (i = 0; i < istop; i += 4)
      {
-         *rp = (png_byte)(~(*rp));
-         *(rp + 1) = (png_byte)(~(*(rp + 1)));
+         *rp = (png_byte)((~(*rp)) & 0xff);
+         *(rp + 1) = (png_byte)((~(*(rp + 1))) & 0xff);
         rp += 4;
      }
   }
@@ -803,8 +803,9 @@ png_set_user_transform_info(png_structrp png_ptr, png_voidp
 #endif

   png_ptr->user_transform_ptr = user_transform_ptr;
-   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
-   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+   png_ptr->user_transform_depth = (png_byte)(user_transform_depth & 0xff);
+   png_ptr->user_transform_channels =
+       (png_byte)(user_transform_channels & 0xff);
 }
 #endif

--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,8 +1,8 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 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.)
 *
@@ -219,7 +219,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
         int j;
         for (j = 0; j<(int)info_ptr->num_trans; j++)
            info_ptr->trans_alpha[j] =
-               (png_byte)(255 - info_ptr->trans_alpha[j]);
+               (png_byte)((255 - info_ptr->trans_alpha[j]) & 0xff);
      }
 #endif
      png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
@@ -457,11 +457,11 @@ png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
   png_debug(1, "in png_convert_from_struct_tm");

   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
-   ptime->month = (png_byte)(ttime->tm_mon + 1);
-   ptime->day = (png_byte)ttime->tm_mday;
-   ptime->hour = (png_byte)ttime->tm_hour;
-   ptime->minute = (png_byte)ttime->tm_min;
-   ptime->second = (png_byte)ttime->tm_sec;
+   ptime->month = (png_byte)((ttime->tm_mon + 1) & 0xff);
+   ptime->day = (png_byte)(ttime->tm_mday & 0xff);
+   ptime->hour = (png_byte)(ttime->tm_hour & 0xff);
+   ptime->minute = (png_byte)(ttime->tm_min & 0xff);
+   ptime->second = (png_byte)(ttime->tm_sec & 0xff);
 }

 void PNGAPI
@@ -638,8 +638,8 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
-            *(rp)     = (png_byte)(*rp       - *(rp + 1));
-            *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
+            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
+            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
         }
      }

@@ -665,10 +665,10 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
-            *(rp    ) = (png_byte)(red >> 8);
-            *(rp + 1) = (png_byte)red;
-            *(rp + 4) = (png_byte)(blue >> 8);
-            *(rp + 5) = (png_byte)blue;
+            *(rp    ) = (png_byte)((red >> 8) & 0xff);
+            *(rp + 1) = (png_byte)(red & 0xff);
+            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp + 5) = (png_byte)(blue & 0xff);
         }
      }
 #endif /* WRITE_16BIT */
@@ -811,7 +811,8 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
   row_info.width = png_ptr->usr_width;
   row_info.channels = png_ptr->usr_channels;
   row_info.bit_depth = png_ptr->usr_bit_depth;
-   row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
+   row_info.pixel_depth =
+       (png_byte)(0xff & (row_info.bit_depth * row_info.channels));
   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);

   png_debug1(3, "row_info->color_type = %d", row_info.color_type);
@@ -1037,7 +1038,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            png_ptr->do_filter = PNG_FILTER_PAETH; break;

         default:
-            png_ptr->do_filter = (png_byte)filters; break;
+            png_ptr->do_filter = (png_byte)(filters & 0xff); break;
 #else
         default:
            png_app_error(png_ptr, "Unknown row filter for method 0");
@@ -1050,8 +1051,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
       * it is too late to start using the filters that need it, since we
       * will be missing the data in the previous row.  If an application
       * wants to start and stop using particular filters during compression,
-       * it should start out with all of the filters, and then remove them
-       * or add them back after the start of compression.
+       * it should start out with all of the filters, and then add and
+       * remove them after the start of compression.
       */
      if (png_ptr->row_buf != NULL)
      {
@@ -1070,8 +1071,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            if (png_ptr->prev_row == NULL)
            {
               png_warning(png_ptr, "Can't add Up filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_UP);
+               png_ptr->do_filter =
+                  (png_byte)((png_ptr->do_filter & ~PNG_FILTER_UP) & 0xff);
            }

            else
@@ -1088,8 +1089,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            if (png_ptr->prev_row == NULL)
            {
               png_warning(png_ptr, "Can't add Average filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_AVG);
+               png_ptr->do_filter =
+                   (png_byte)((png_ptr->do_filter & ~PNG_FILTER_AVG) & 0xff);
            }

            else
@@ -1106,7 +1107,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            if (png_ptr->prev_row == NULL)
            {
               png_warning(png_ptr, "Can't add Paeth filter after starting");
-               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
+               png_ptr->do_filter &= (png_byte)((~PNG_FILTER_PAETH) & 0xff);
            }

            else
@@ -1210,7 +1211,7 @@ png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method,
         }

         /* Safe to set this now */
-         png_ptr->num_prev_filters = (png_byte)num_weights;
+         png_ptr->num_prev_filters = (png_byte)(num_weights & 0xff);
      }

      /* If, in the future, there are other filter methods, this would
@@ -1418,8 +1419,8 @@ png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
   if (png_ptr == NULL)
      return;

-   /* Prior to 1.6.0 this would warn but then set the window_bits value. This
-    * meant that negative window bits values could be selected that would cause
+   /* Prior to 1.6.0 this would warn but then set the window_bits value, this
+    * meant that negative window bits values could be selected which would cause
    * libpng to write a non-standard PNG file with raw deflate or gzip
    * compressed IDAT or ancillary chunks.  Such files can be read and there is
    * no warning on read, so this seems like a very bad idea.
@@ -1890,7 +1891,7 @@ png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
         component *= 255;

      /* Convert the component to sRGB. */
-      return (png_byte)PNG_sRGB_FROM_LINEAR(component);
+      return (png_byte)(PNG_sRGB_FROM_LINEAR(component) & 0xff);
   }

   else
@@ -1939,7 +1940,7 @@ png_write_image_8bit(png_voidp argument)
         while (out_ptr < row_end)
         {
            png_uint_16 alpha = in_ptr[aindex];
-            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_byte alphabyte = (png_byte)(PNG_DIV257(alpha) & 0xff);
            png_uint_32 reciprocal = 0;
            int c;

@@ -1982,7 +1983,7 @@ png_write_image_8bit(png_voidp argument)
            png_uint_32 component = *in_ptr++;

            component *= 255;
-            *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
+            *out_ptr++ = (png_byte)(PNG_sRGB_FROM_LINEAR(component) & 0xff);
         }

         png_write_row(png_ptr, output_row);
@@ -2041,23 +2042,23 @@ png_image_set_PLTE(png_image_write_control *display)
         {
            if (channels >= 3) /* RGB */
            {
-               palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[(2 ^ bgr)]);
-               palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[1]);
-               palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[bgr]);
+               palette[i].blue = (png_byte)(0xff & PNG_sRGB_FROM_LINEAR(255 *
+                  entry[(2 ^ bgr)]));
+               palette[i].green = (png_byte)(0xff & PNG_sRGB_FROM_LINEAR(255 *
+                  entry[1]));
+               palette[i].red = (png_byte)(0xff & PNG_sRGB_FROM_LINEAR(255 *
+                  entry[bgr]));
            }

            else /* Gray */
               palette[i].blue = palette[i].red = palette[i].green =
-                  (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
+                  (png_byte)(PNG_sRGB_FROM_LINEAR((255 * *entry)) & 0xff);
         }

         else /* alpha */
         {
            png_uint_16 alpha = entry[afirst ? 0 : channels-1];
-            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_byte alphabyte = (png_byte)(PNG_DIV257(alpha) & 0xff);
            png_uint_32 reciprocal = 0;

            /* Calculate a reciprocal, as in the png_write_image_8bit code above
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,8 +1,8 @@

 /* pngwtran.c - transforms the data in a row for PNG writers
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 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.)
 *
@@ -56,14 +56,14 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
               else
               {
                  mask = 0x80;
-                  *dp = (png_byte)v;
+                  *dp = (png_byte)(v & 0xff);
                  dp++;
                  v = 0;
               }
            }

            if (mask != 0x80)
-               *dp = (png_byte)v;
+               *dp = (png_byte)(v & 0xff);

            break;
         }
@@ -90,7 +90,7 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
               if (shift == 0)
               {
                  shift = 6;
-                  *dp = (png_byte)v;
+                  *dp = (png_byte)(v & 0xff);
                  dp++;
                  v = 0;
               }
@@ -102,7 +102,7 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
            }

            if (shift != 6)
-               *dp = (png_byte)v;
+               *dp = (png_byte)(v & 0xff);

            break;
         }
@@ -129,7 +129,7 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
               if (shift == 0)
               {
                  shift = 4;
-                  *dp = (png_byte)v;
+                  *dp = (png_byte)(v & 0xff);
                  dp++;
                  v = 0;
               }
@@ -141,7 +141,7 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
            }

            if (shift != 4)
-               *dp = (png_byte)v;
+               *dp = (png_byte)(v & 0xff);

            break;
         }
@@ -150,8 +150,9 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
            break;
      }

-      row_info->bit_depth = (png_byte)bit_depth;
-      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+      row_info->bit_depth = (png_byte)(bit_depth & 0xff);
+      row_info->pixel_depth =
+          (png_byte)((bit_depth * row_info->channels) & 0xff);
      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
          row_info->width);
   }
@@ -422,7 +423,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = *(sp++);
               */
               sp+=3; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
            }
         }

@@ -445,8 +446,8 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = *(sp++);
               */
               sp+=6; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
            }
         }
 #endif /* WRITE_16BIT */
@@ -464,7 +465,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               *(dp++) = *(sp++);
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
            }
         }

@@ -483,8 +484,8 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = *(sp++);
               */
               sp+=2; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
+               *(dp++) = (png_byte)((255 - *(sp++)) & 0xff);
            }
         }
 #endif /* WRITE_16BIT */
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -23,10 +23,10 @@
 void PNGAPI
 png_save_uint_32(png_bytep buf, png_uint_32 i)
 {
-   buf[0] = (png_byte)(i >> 24);
-   buf[1] = (png_byte)(i >> 16);
-   buf[2] = (png_byte)(i >> 8);
-   buf[3] = (png_byte)(i     );
+   buf[0] = (png_byte)((i >> 24) & 0xff);
+   buf[1] = (png_byte)((i >> 16) & 0xff);
+   buf[2] = (png_byte)((i >> 8) & 0xff);
+   buf[3] = (png_byte)(i & 0xff);
 }

 /* Place a 16-bit number into a buffer in PNG byte order.
@@ -36,8 +36,8 @@ png_save_uint_32(png_bytep buf, png_uint_32 i)
 void PNGAPI
 png_save_uint_16(png_bytep buf, unsigned int i)
 {
-   buf[0] = (png_byte)(i >> 8);
-   buf[1] = (png_byte)(i     );
+   buf[0] = (png_byte)((i >> 8) & 0xff);
+   buf[1] = (png_byte)(i & 0xff);
 }
 #endif

@@ -278,10 +278,10 @@ optimize_cmf(png_bytep data, png_alloc_size_t data_size)

            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);

-            data[0] = (png_byte)z_cmf;
+            data[0] = (png_byte)(z_cmf & 0xff);
            tmp = data[1] & 0xe0;
            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
-            data[1] = (png_byte)tmp;
+            data[1] = (png_byte)(tmp & 0xff);
         }
      }
   }
@@ -695,7 +695,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

   while (*key && key_len < 79)
   {
-      png_byte ch = (png_byte)*key++;
+      png_byte ch = (png_byte)(0xff & *key++);

      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
         *new_key++ = ch, ++key_len, space = 0;
@@ -872,17 +872,17 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
 #endif

   /* Save the relevant information */
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->color_type = (png_byte)color_type;
-   png_ptr->interlaced = (png_byte)interlace_type;
+   png_ptr->bit_depth = (png_byte)(bit_depth & 0xff);
+   png_ptr->color_type = (png_byte)(color_type & 0xff);
+   png_ptr->interlaced = (png_byte)(interlace_type & 0xff);
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_ptr->filter_type = (png_byte)filter_type;
+   png_ptr->filter_type = (png_byte)(filter_type & 0xff);
 #endif
-   png_ptr->compression_type = (png_byte)compression_type;
+   png_ptr->compression_type = (png_byte)(compression_type & 0xff);
   png_ptr->width = width;
   png_ptr->height = height;

-   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+   png_ptr->pixel_depth = (png_byte)((bit_depth * png_ptr->channels) & 0xff);
   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
   /* Set the usr info, so any transformations can modify it */
   png_ptr->usr_width = png_ptr->width;
@@ -892,11 +892,11 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
   /* Pack the header information into the buffer */
   png_save_uint_32(buf, width);
   png_save_uint_32(buf + 4, height);
-   buf[8] = (png_byte)bit_depth;
-   buf[9] = (png_byte)color_type;
-   buf[10] = (png_byte)compression_type;
-   buf[11] = (png_byte)filter_type;
-   buf[12] = (png_byte)interlace_type;
+   buf[8] = (png_byte)(bit_depth & 0xff);
+   buf[9] = (png_byte)(color_type & 0xff);
+   buf[10] = (png_byte)(compression_type & 0xff);
+   buf[11] = (png_byte)(filter_type & 0xff);
+   buf[12] = (png_byte)(interlace_type & 0xff);

   /* Write the chunk */
   png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
@@ -1181,7 +1181,7 @@ png_write_sRGB(png_structrp png_ptr, int srgb_intent)
      png_warning(png_ptr,
          "Invalid sRGB rendering intent specified");

-   buf[0]=(png_byte)srgb_intent;
+   buf[0]=(png_byte)(srgb_intent & 0xff);
   png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
 }
 #endif
@@ -1285,10 +1285,10 @@ png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
   {
      if (spalette->depth == 8)
      {
-         entrybuf[0] = (png_byte)ep->red;
-         entrybuf[1] = (png_byte)ep->green;
-         entrybuf[2] = (png_byte)ep->blue;
-         entrybuf[3] = (png_byte)ep->alpha;
+         entrybuf[0] = (png_byte)(ep->red & 0xff);
+         entrybuf[1] = (png_byte)(ep->green & 0xff);
+         entrybuf[2] = (png_byte)(ep->blue & 0xff);
+         entrybuf[3] = (png_byte)(ep->alpha & 0xff);
         png_save_uint_16(entrybuf + 4, ep->frequency);
      }

@@ -1309,10 +1309,10 @@ png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
   {
      if (spalette->depth == 8)
      {
-         entrybuf[0] = (png_byte)ep[i].red;
-         entrybuf[1] = (png_byte)ep[i].green;
-         entrybuf[2] = (png_byte)ep[i].blue;
-         entrybuf[3] = (png_byte)ep[i].alpha;
+         entrybuf[0] = (png_byte)(ep[i].red & 0xff);
+         entrybuf[1] = (png_byte)(ep[i].green & 0xff);
+         entrybuf[2] = (png_byte)(ep[i].blue & 0xff);
+         entrybuf[3] = (png_byte)(ep[i].alpha & 0xff);
         png_save_uint_16(entrybuf + 4, ep[i].frequency);
      }

@@ -1348,8 +1348,8 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
   {
      png_byte maxbits;

-      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
-          png_ptr->usr_bit_depth);
+      maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+         (png_byte)(png_ptr->usr_bit_depth & 0xff);

      if (sbit->red == 0 || sbit->red > maxbits ||
          sbit->green == 0 || sbit->green > maxbits ||
@@ -1786,7 +1786,7 @@ png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,

   png_save_int_32(buf, x_offset);
   png_save_int_32(buf + 4, y_offset);
-   buf[8] = (png_byte)unit_type;
+   buf[8] = (png_byte)(unit_type & 0xff);

   png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
 }
@@ -1841,8 +1841,8 @@ png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
   png_write_chunk_data(png_ptr, new_purpose, purpose_len);
   png_save_int_32(buf, X0);
   png_save_int_32(buf + 4, X1);
-   buf[8] = (png_byte)type;
-   buf[9] = (png_byte)nparams;
+   buf[8] = (png_byte)(type & 0xff);
+   buf[9] = (png_byte)(nparams & 0xff);
   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
   png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);

@@ -1877,7 +1877,7 @@ png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
      return;
   }

-   buf[0] = (png_byte)unit;
+   buf[0] = (png_byte)(unit & 0xff);
   memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
   memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */

@@ -1902,7 +1902,7 @@ png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,

   png_save_uint_32(buf, x_pixels_per_unit);
   png_save_uint_32(buf + 4, y_pixels_per_unit);
-   buf[8] = (png_byte)unit_type;
+   buf[8] = (png_byte)(unit_type & 0xff);

   png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
 }
@@ -1968,7 +1968,7 @@ png_write_start_row(png_structrp png_ptr)

   /* 1.5.6: added to allow checking in the row write code. */
   png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
-   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
+   png_ptr->maximum_pixel_depth = (png_byte)(usr_pixel_depth & 0xff);

   /* Set up row buffer */
   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
@@ -2180,7 +2180,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
               if (shift == 0)
               {
                  shift = 7;
-                  *dp++ = (png_byte)d;
+                  *dp++ = (png_byte)(d & 0xff);
                  d = 0;
               }

@@ -2189,7 +2189,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)

            }
            if (shift != 7)
-               *dp = (png_byte)d;
+               *dp = (png_byte)(d & 0xff);

            break;
         }
@@ -2218,7 +2218,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
               if (shift == 0)
               {
                  shift = 6;
-                  *dp++ = (png_byte)d;
+                  *dp++ = (png_byte)(d & 0xff);
                  d = 0;
               }

@@ -2226,7 +2226,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
                  shift -= 2;
            }
            if (shift != 6)
-               *dp = (png_byte)d;
+               *dp = (png_byte)(d & 0xff);

            break;
         }
@@ -2254,7 +2254,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
               if (shift == 0)
               {
                  shift = 4;
-                  *dp++ = (png_byte)d;
+                  *dp++ = (png_byte)(d & 0xff);
                  d = 0;
               }

@@ -2262,7 +2262,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
                  shift -= 4;
            }
            if (shift != 4)
-               *dp = (png_byte)d;
+               *dp = (png_byte)(d & 0xff);

            break;
         }
@@ -2453,7 +2453,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (lp = row_buf + 1; i < row_bytes;
         i++, rp++, lp++, dp++)
      {
-         *dp = (png_byte)((int)*rp - (int)*lp);
+         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
      }

      best_row = png_ptr->sub_row;
@@ -2515,7 +2515,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (lp = row_buf + 1; i < row_bytes;
         i++, rp++, lp++, dp++)
      {
-         v = *dp = (png_byte)((int)*rp - (int)*lp);
+         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);

         sum += (v < 128) ? v : 256 - v;

@@ -2574,7 +2574,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
          pp = prev_row + 1; i < row_bytes;
          i++, rp++, pp++, dp++)
      {
-         *dp = (png_byte)((int)*rp - (int)*pp);
+         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
      }

      best_row = png_ptr->up_row;
@@ -2625,7 +2625,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
          pp = prev_row + 1; i < row_bytes; i++)
      {
-         v = *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

         sum += (v < 128) ? v : 256 - v;

@@ -2683,13 +2683,13 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
           pp = prev_row + 1; i < bpp; i++)
      {
-         *dp++ = (png_byte)((int)*rp++ - ((int)*pp++ / 2));
+         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
      }

      for (lp = row_buf + 1; i < row_bytes; i++)
      {
         *dp++ =
-             (png_byte)((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2));
+             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
      }
      best_row = png_ptr->avg_row;
   }
@@ -2738,7 +2738,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
           pp = prev_row + 1; i < bpp; i++)
      {
-         v = *dp++ = (png_byte)((int)*rp++ - ((int)*pp++ / 2));
+         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);

         sum += (v < 128) ? v : 256 - v;
      }
@@ -2746,7 +2746,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (lp = row_buf + 1; i < row_bytes; i++)
      {
         v = *dp++ =
-             (png_byte)(((int)*rp++ - ((int)*pp++ + (int)*lp++) / 2));
+             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);

         sum += (v < 128) ? v : 256 - v;

@@ -2804,7 +2804,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
          pp = prev_row + 1; i < bpp; i++)
      {
-         *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
      }

      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
@@ -2830,7 +2830,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)

         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;

-         *dp++ = (png_byte)((int)*rp++ - p);
+         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
      }
      best_row = png_ptr->paeth_row;
   }
@@ -2879,7 +2879,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
          pp = prev_row + 1; i < bpp; i++)
      {
-         v = *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

         sum += (v < 128) ? v : 256 - v;
      }
@@ -2921,7 +2921,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
            p = c;
 #endif /* SLOW_PAETH */

-         v = *dp++ = (png_byte)((int)*rp++ - p);
+         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

         sum += (v < 128) ? v : 256 - v;

--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.17rc06 - March 23, 2015
+libpng version 1.6.17beta06 - February 28, 2015

 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 1.6.17rc06 - March 23, 2015
+ * libpng version 1.6.17beta06 - February 28, 2015
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.17rc06 - March 23, 2015
+Makefiles for  libpng version 1.6.17beta06 - February 28, 2015

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.17rc06)
+                       (gcc, creates libpng16.so.16.1.6.17beta06)
 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.16.1.6.17rc06)
+                       creates libpng16.so.16.1.6.17beta06)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.17rc06)
+                       creates libpng16.so.16.1.6.17beta06)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.17rc06)
+                       creates libpng16.so.16.1.6.17beta06)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.c
+++ b/scripts/def.c
@@ -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 1.6.17rc06"
+PNG_DFN ";Version 1.6.17beta06"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/dfn.awk
+++ b/scripts/dfn.awk
@@ -17,7 +17,7 @@
 BEGIN{
   out="/dev/null"       # as a flag
   out_count=0           # count of output lines
-   err=0                 # set if an error occurred
+   err=0                 # set if an error occured
   sort=0                # sort the output
   array[""]=""
 }
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.6.17rc06
+version=1.6.17beta06
 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: 1.6.17rc06
+Version: 1.6.17beta06
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include/libpng16

 LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.6.17rc06
+SHLIB_MINOR=	1.6.17beta06
 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=	1.6.17rc06
+SHLIB_MINOR=	1.6.17beta06
 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=	1.6.17rc06
+SHLIB_MINOR=	1.6.17beta06

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/makefile.std
+++ b/scripts/makefile.std
@@ -106,8 +106,7 @@ install: libpng.a pnglibconf.h
 	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a

 clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h pnglibconf.c \
-	pnglibconf.out
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.*

 DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
 writelock:
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -367,14 +367,11 @@ option USER_LIMITS requires READ
 # USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
 #
 # Only chunks that are variable in number are counted towards the
-
-# Use 0x7fffffff for unlimited
-setting USER_WIDTH_MAX default        1000000
-setting USER_HEIGHT_MAX default       1000000
-
-# Use 0 for unlimited
-setting USER_CHUNK_CACHE_MAX default     1000
-setting USER_CHUNK_MALLOC_MAX default 8000000
+# USER_CHUNK_CACHE_MAX limit
+setting USER_WIDTH_MAX default        1000000 /* Use 0x7fffffff for unlimited */
+setting USER_HEIGHT_MAX default       1000000 /* Use 0x7fffffff for unlimited */
+setting USER_CHUNK_CACHE_MAX default     1000 /* Use 0 for unlimited */
+setting USER_CHUNK_MALLOC_MAX default 8000000 /* Use 0 for unlimited */

 # If this option is enabled APIs to set the above limits at run time are added;
 # without this the hardwired (compile time) limits will be used.
@@ -646,7 +643,7 @@ setting QUANTIZE_BLUE_BITS default 5
 # are only interested in 8 bits anyway.  Increasing this value
 # results in more memory being used, and more pow() functions
 # being called to fill in the gamma tables.  Don't set this value
-# less than 8, and even that may not work (I haven't tested it).
+# less then 8, and even that may not work (I haven't tested it).

 setting MAX_GAMMA_8 default 11

--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.17rc06 STANDARD API DEFINITION */
+/* libpng 1.6.17beta06 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.17rc06 - March 23, 2015 */
+/* Libpng version 1.6.17beta06 - February 28, 2015 */

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

@@ -198,10 +198,10 @@
 #define PNG_QUANTIZE_RED_BITS 5
 #define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
 #define PNG_TEXT_Z_DEFAULT_STRATEGY 0
-#define PNG_USER_CHUNK_CACHE_MAX 1000
-#define PNG_USER_CHUNK_MALLOC_MAX 8000000
-#define PNG_USER_HEIGHT_MAX 1000000
-#define PNG_USER_WIDTH_MAX 1000000
+#define PNG_USER_CHUNK_CACHE_MAX 1000 /* Use 0 for unlimited */
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000 /* Use 0 for unlimited */
+#define PNG_USER_HEIGHT_MAX 1000000 /* Use 0x7fffffff for unlimited */
+#define PNG_USER_WIDTH_MAX 1000000 /* Use 0x7fffffff for unlimited */
 #define PNG_WEIGHT_SHIFT 8
 #define PNG_ZBUF_SIZE 8192
 #define PNG_ZLIB_VERNUM 0 /* unknown */
--- a/scripts/pnglibconf.mak
+++ b/scripts/pnglibconf.mak
@@ -49,7 +49,6 @@ pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $
 	$(MOVE) pnglibconf.tmp $@

 clean-pnglibconf:
-	$(DELETE) pnglibconf.h pnglibconf.c pnglibconf.out pnglibconf.pre \
-	pnglibconf.dfn
+	$(DELETE) pnglibconf.*

 clean: clean-pnglibconf
--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.17rc06
+;Version 1.6.17beta06
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng