[libpng16] Imported from libpng-1.6.17beta06.tar

[libpng16] Added "& 0xff" to things being typecast to "png_byte".
[libpng16] Avoid runtime checks when converting integer to png_byte with
2025-07-10 18:04:09 +02:00 · 2015-02-27 18:55:51 -06:00 · 2015-02-27 18:53:44 -06:00 · 2015-02-27 18:47:43 -06:00 · 2015-02-26 10:39:13 -06:00 · 2015-02-25 15:42:16 -06:00
36 changed files with 326 additions and 294 deletions
--- a/25
+++ b/25
@@ -1,4 +1,4 @@
-Libpng 1.6.17beta05 - February 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

-   1.6.17beta05.tar.xz (LZMA-compressed, recommended)
-   1.6.17beta05.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

-   lp1617b05.7z  (LZMA-compressed, recommended)
-   lp1617b05.zip
+   lp1617b06.7z  (LZMA-compressed, recommended)
+   lp1617b06.zip

 Other information:

-   1.6.17beta05-README.txt
-   1.6.17beta05-LICENSE.txt
-   libpng-1.6.17beta05-*.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):

@@ -56,7 +56,14 @@ Version 1.6.17beta04 [February 21, 2015]
  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6

-Version 1.6.17beta05 [February 23, 2015]
+Version 1.6.17beta05 [February 25, 2015]
+  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+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)

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/9
+++ b/9
@@ -5157,7 +5157,14 @@ Version 1.6.17beta04 [February 21, 2015]
  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6

-Version 1.6.17beta05 [February 23, 2015]
+Version 1.6.17beta05 [February 25, 2015]
+  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+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)

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -253,7 +253,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.17beta05
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.17beta06
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
--- 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 1.6.17beta05, February 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
-February 23, 2015
+February 28, 2015
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-README for libpng version 1.6.17beta05 - February 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],[1.6.17beta05],[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=1.6.17beta05
+PNGLIB_VERSION=1.6.17beta06
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
 PNGLIB_RELEASE=17
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -3702,21 +3702,21 @@ usage(const char *prog)
 "        gAMA, sRGB [all]: These specify the gamma encoding used for the pixel",
 "            values.",
 "        cHRM, iCCP [color]: These specify how colors are encoded.  iCCP also",
-"            specifies the exact encoding of a pixel value however in practice",
-"            most programs will ignore it.",
+"            specifies the exact encoding of a pixel value; however, in",
+"            practice most programs will ignore it.",
 "        bKGD [transform]: This is used by libpng transforms."
 "    --max=<number>:",
 "      Use IDAT chunks sized <number>.  If no number is given the the IDAT",
 "      chunks will be the maximum size permitted; 2^31-1 bytes.  If the option",
 "      is omitted the original chunk sizes will not be changed.  When the",
-"      option is given --strip=unsafe is set automatically, this may be",
+"      option is given --strip=unsafe is set automatically. This may be",
 "      cancelled if you know that all unknown unsafe-to-copy chunks really are",
 "      safe to copy across an IDAT size change.  This is true of all chunks",
 "      that have ever been formally proposed as PNG extensions.",
 "  MESSAGES",
 "      By default the program only outputs summaries for each file.",
 "    --quiet (-q):",
-"      Do not output the summaries except for files which cannot be read. With",
+"      Do not output the summaries except for files that cannot be read. With",
 "      two --quiets these are not output either.",
 "    --errors (-e):",
 "      Output errors from libpng and the program (except too-far-back).",
@@ -3749,7 +3749,7 @@ usage(const char *prog)
 "  the following codes.  Notice that the results for each file are combined",
 "  together - check one file at a time to get a meaningful error code!",
 "    0x01: The zlib too-far-back error existed in at least one chunk.",
-"    0x02: At least once chunk had a CRC error.",
+"    0x02: At least one chunk had a CRC error.",
 "    0x04: A chunk length was incorrect.",
 "    0x08: The file was truncated.",
 "  Errors less than 16 are potentially recoverable, for a single file if the",
@@ -3817,7 +3817,7 @@ usage(const char *prog)
 "          SKP: The chunk was skipped because of a zlib issue (zlib-rc) with",
 "               explanation 'message'",
 "          ERR: The read of the file was aborted.  The parameters explain why.",
-"$3 status:     For 'ERR' the accumulate status code from 'EXIT CODES' above.",
+"$3 status:     For 'ERR' the accumulated status code from 'EXIT CODES' above.",
 "               This is printed as a 2 digit hexadecimal value",
 "   comp-level: The recorded compression level (FLEVEL) of a zlib stream",
 "               expressed as a string {supfast,stdfast,default,maximum}",
--- 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 1.6.17beta05 - February 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 1.6.17beta05 - February 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

@@ -5275,13 +5275,13 @@ Other rules can be inferred by inspecting the libpng source.

 XVI. Y2K Compliance in libpng

-February 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 1.6.17beta05 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 "February 23, 2015"
+.TH LIBPNG 3 "February 28, 2015"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17beta05
+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 1.6.17beta05 - February 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 1.6.17beta05 - February 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

@@ -5779,13 +5779,13 @@ Other rules can be inferred by inspecting the libpng source.

 .SH XVI. Y2K Compliance in libpng

-February 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 1.6.17beta05 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
@@ -6037,7 +6037,7 @@ the first widely used release:
 1.6.16beta01-03     16    10616  16.so.16.16[.0]
 1.6.16rc01-02       16    10616  16.so.16.16[.0]
 1.6.16              16    10616  16.so.16.16[.0]
- 1.6.17beta01-05     16    10617  16.so.16.17[.0]
+ 1.6.17beta01-06     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
@@ -6094,7 +6094,7 @@ possible without all of you.

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

-Libpng version 1.6.17beta05 - February 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).

@@ -6117,7 +6117,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.17beta05, February 23, 2015, 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
@@ -6216,7 +6216,7 @@ certification mark of the Open Source Initiative.

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

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "February 23, 2015"
+.TH LIBPNGPF 3 "February 28, 2015"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.17beta05
+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 "February 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_17beta05 Your_png_h_is_not_version_1_6_17beta05;
+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
@@ -34,7 +34,7 @@ png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
   if (num_bytes > 8)
      png_error(png_ptr, "Too many bytes for PNG signature");

-   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
+   png_ptr->sig_bytes = (png_byte)((num_bytes < 0 ? 0 : num_bytes) & 0xff);
 }

 /* Checks whether the supplied bytes match the PNG signature.  We allow
@@ -772,13 +772,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-     "libpng version 1.6.17beta05 - February 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 1.6.17beta05 - February 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.";
@@ -875,9 +875,9 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)

   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
   {
-      palette[i].red = (png_byte)v;
-      palette[i].green = (png_byte)v;
-      palette[i].blue = (png_byte)v;
+      palette[i].red = (png_byte)(v & 0xff);
+      palette[i].green = (png_byte)(v & 0xff);
+      palette[i].blue = (png_byte)(v & 0xff);
   }
 }
 #endif
@@ -3733,7 +3733,7 @@ png_exp8bit(png_fixed_point lg2)
    * step.
    */
   x -= x >> 8;
-   return (png_byte)((x + 0x7fffffU) >> 24);
+   return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
 }

 #ifdef PNG_16BIT_SUPPORTED
@@ -3794,7 +3794,7 @@ png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
 #     endif
   }

-   return (png_byte)value;
+   return (png_byte)(value & 0xff);
 }

 #ifdef PNG_16BIT_SUPPORTED
@@ -4016,7 +4016,7 @@ png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,

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

 /* Used from png_read_destroy and below to release the memory used by the gamma
@@ -4156,7 +4156,8 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
      *
      */
     if (sig_bit > 0 && sig_bit < 16U)
-        shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */
+        /* shift == insignificant bits */
+        shift = (png_byte)((16U - sig_bit) & 0xff);

     else
        shift = 0; /* keep all 16 bits */
@@ -4225,7 +4226,7 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
      int setting = (2 + (onoff != 0)) << option;
      int current = png_ptr->options;

-      png_ptr->options = (png_byte)((current & ~mask) | setting);
+      png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);

      return (current & mask) >> option;
   }
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.17beta05, February 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.)
@@ -11,7 +11,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.17beta05, February 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:
@@ -212,7 +212,7 @@
 *    1.6.16beta01-03         16    10616  16.so.16.16[.0]
 *    1.6.16rc01-02           16    10616  16.so.16.16[.0]
 *    1.6.16                  16    10616  16.so.16.16[.0]
- *    1.6.17beta01-05         16    10617  16.so.16.17[.0]
+ *    1.6.17beta01-06         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
@@ -244,7 +244,7 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.17beta05, February 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:
@@ -356,13 +356,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    February 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 1.6.17beta05 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
@@ -424,9 +424,9 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.17beta05"
+#define PNG_LIBPNG_VER_STRING "1.6.17beta06"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.17beta05 - February 23, 2015\n"
+     " libpng version 1.6.17beta06 - February 28, 2015\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -440,7 +440,7 @@
 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
 */

-#define PNG_LIBPNG_VER_BUILD  05
+#define PNG_LIBPNG_VER_BUILD  06

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -570,7 +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_17beta05;
+typedef char* png_libpng_version_1_6_17beta06;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -1579,6 +1579,7 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
 #define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
 #define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */

+#ifdef PNG_WRITE_SUPPORTED
 /* These functions give the user control over the scan-line filtering in
 * libpng and the compression methods used by zlib.  These functions are
 * mainly useful for testing, as the defaults should work with most users.
@@ -1663,7 +1664,6 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
 #define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
 #define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */

-#ifdef PNG_WRITE_SUPPORTED
 /* Set the library compression level.  Currently, valid values range from
 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
 * (0 - no compression, 9 - "maximal" compression).  Note that tests have
@@ -2667,26 +2667,28 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
           * (png_uint_16)(alpha)                         \
           + (png_uint_16)(bg)*(png_uint_16)(255          \
           - (png_uint_16)(alpha)) + 128);                \
-       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
+       (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }

 #  define png_composite_16(composite, fg, alpha, bg)       \
     { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg)  \
           * (png_uint_32)(alpha)                          \
           + (png_uint_32)(bg)*(65535                      \
           - (png_uint_32)(alpha)) + 32768);               \
-       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
+       (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }

 #else  /* Standard method using integer division */

-#  define png_composite(composite, fg, alpha, bg)                          \
-     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
-     (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
-     127) / 255)
+#  define png_composite(composite, fg, alpha, bg)                        \
+     (composite) =                                                       \
+         (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
+         (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
+         127) / 255))

 #  define png_composite_16(composite, fg, alpha, bg)                         \
-     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
-     (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +         \
-     32767) / 65535)
+     (composite) =                                                           \
+         (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+         (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +     \
+         32767) / 65535))
 #endif /* READ_COMPOSITE_NODIV */

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.17beta05, (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)
--- 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/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/pngpriv.h
+++ b/pngpriv.h
@@ -741,15 +741,17 @@
 * macro will fail on top-bit-set values because of the sign extension.
 */
 #define PNG_CHUNK_FROM_STRING(s)\
-   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
+   PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])

 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
 * signed and the argument is a (char[])  This macro will fail miserably on
 * systems where (char) is more than 8 bits.
 */
 #define PNG_STRING_FROM_CHUNK(s,c)\
-   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
-   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
+   (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
+   ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
+   ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
+   ((char*)(s))[3]=(char)((c & 0xff)))

 /* Do the same but terminate with a null character. */
 #define PNG_CSTRING_FROM_CHUNK(s,c)\
@@ -811,8 +813,9 @@ PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);

-#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
-   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
+#define PNG_sRGB_FROM_LINEAR(linear) \
+  ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
+   + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
    * encoded value with maximum error 0.646365.  Note that the input is not a
    * 16-bit value; it has been multiplied by 255! */
--- a/pngread.c
+++ b/pngread.c
@@ -2052,7 +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)
@@ -3025,7 +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/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
@@ -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 & 0xff);
+               *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);
@@ -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
@@ -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
@@ -3686,9 +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)
@@ -3815,15 +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
@@ -3833,8 +3837,8 @@ 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);

@@ -3870,15 +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)
@@ -4065,11 +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++;
               }
            }
@@ -4400,8 +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;
@@ -4425,7 +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;
@@ -4496,7 +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);
         }
@@ -4563,7 +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);
      }
   }
@@ -4596,7 +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
@@ -4984,8 +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;
@@ -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
--- a/pngtest.c
+++ b/pngtest.c
@@ -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_17beta05 Your_png_h_is_not_version_1_6_17beta05;
+typedef png_libpng_version_1_6_17beta06 Your_png_h_is_not_version_1_6_17beta06;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -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
@@ -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
@@ -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");
@@ -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
@@ -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
@@ -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
@@ -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);
         }
      }
   }
@@ -871,18 +871,18 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
   interlace_type=PNG_INTERLACE_NONE;
 #endif

-   /* Save the relevent information */
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->color_type = (png_byte)color_type;
-   png_ptr->interlaced = (png_byte)interlace_type;
+   /* Save the relevant information */
+   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;
         }
@@ -2688,8 +2688,8 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)

      for (lp = row_buf + 1; i < row_bytes; i++)
      {
-         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
-                 & 0xff);
+         *dp++ =
+             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
      }
      best_row = png_ptr->avg_row;
   }
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.17beta05 - February 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 1.6.17beta05 - February 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 1.6.17beta05 - February 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.16.1.6.17beta05)
+                       (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.16.1.6.17beta05)
+                       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.16.1.6.17beta05)
+                       creates libpng16.so.16.1.6.17beta06)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.17beta05)
+                       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 1.6.17beta05"
+PNG_DFN ";Version 1.6.17beta06"

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

 # Modeled after libxml-config.

-version=1.6.17beta05
+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: 1.6.17beta05
+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=	1.6.17beta05
+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=	1.6.17beta05
+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=	1.6.17beta05
+SHLIB_MINOR=	1.6.17beta06

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.17beta05 STANDARD API DEFINITION */
+/* libpng 1.6.17beta06 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.17beta05 - February 23, 2015 */
+/* Libpng version 1.6.17beta06 - February 28, 2015 */

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

--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.17beta05
+;Version 1.6.17beta06
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
Author	SHA1	Message	Date
Glenn Randers-Pehrson	0bd224ff24	[libpng16] Imported from libpng-1.6.17beta06.tar	2015-02-27 18:55:51 -06:00
Glenn Randers-Pehrson	7011a8cec3	[libpng16] Added "& 0xff" to things being typecast to "png_byte".	2015-02-27 18:53:44 -06:00
Sergey Kosarevsky	9a3de48b48	[libpng16] Avoid runtime checks when converting integer to png_byte with Visual Studio (Sergey Kosarevsky)	2015-02-27 18:47:43 -06:00
Glenn Randers-Pehrson	494e75ac83	[libpng16] Fixed some typos in the pngfix usage message.	2015-02-26 10:39:13 -06:00
Glenn Randers-Pehrson	3f49c1e42a	[libpng16] Bump version to 1.6.17beta06	2015-02-25 15:42:16 -06:00