libpng: update to 1.6.22

2 files changed, 773 insertions, 717 deletions

diff --git a/package/libpng/Makefile b/package/libpng/Makefile
index 9ba92e60d..8026f9ae5 100644
--- a/package/libpng/Makefile
+++ b/package/libpng/Makefile
@@ -4,9 +4,9 @@
 include ${ADK_TOPDIR}/rules.mk
 
 PKG_NAME:=		libpng
-PKG_VERSION:=		1.6.20
+PKG_VERSION:=		1.6.22
 PKG_RELEASE:=		1
-PKG_HASH:=		55c5959e9f3484d96141a3226c53bc9da42a4845e70879d3e1d6e94833d1918b
+PKG_HASH:=		6b5a6ad5c5801ec4d24aacc87a0ed7b666cd586478174f69368a1d7747715226
 PKG_DESCR:=		library for reading/writing png images
 PKG_SECTION:=		libs/image
 PKG_DEPENDS:=		zlib
diff --git a/package/libpng/patches/libpng-1.6.19-apng.patch b/package/libpng/patches/libpng-1.6.22-apng.patch
index 6a3f862b3..66440b70f 100644
--- a/package/libpng/patches/libpng-1.6.19-apng.patch
+++ b/package/libpng/patches/libpng-1.6.22-apng.patch
@@ -1,147 +1,129 @@
-diff -Naru libpng-1.6.19.org/png.h libpng-1.6.19/png.h
---- libpng-1.6.19.org/png.h	2015-11-15 22:34:42.407615478 +0900
-+++ libpng-1.6.19/png.h	2015-11-15 22:34:42.476617887 +0900
-@@ -334,6 +334,10 @@
- #   include "pnglibconf.h"
- #endif
+Index: LICENSE
+===================================================================
+--- LICENSE
++++ LICENSE
+@@ -8,6 +8,12 @@
+ If you modify libpng you may insert additional notices immediately following
+ this sentence.
  
-+#define PNG_APNG_SUPPORTED
-+#define PNG_READ_APNG_SUPPORTED
-+#define PNG_WRITE_APNG_SUPPORTED
++This modified version of libpng code adds animated PNG support and is
++released under the libpng license described below. The modifications are
++Copyright (c) 2006-2007 Andrew Smith, Copyright (c) 2008-2016 Max Stepin,
++and are delimited by "#ifdef PNG_APNG_SUPPORTED / #endif" directives
++surrounding them in the modified libpng source files.
 +
- #ifndef PNG_VERSION_INFO_ONLY
-    /* Machine specific configuration. */
- #  include "pngconf.h"
-@@ -429,6 +433,17 @@
-  * See pngconf.h for base types that vary by machine/system
-  */
+ This code is released under the libpng license.
  
-+#ifdef PNG_APNG_SUPPORTED
-+/* dispose_op flags from inside fcTL */
-+#define PNG_DISPOSE_OP_NONE        0x00
-+#define PNG_DISPOSE_OP_BACKGROUND  0x01
-+#define PNG_DISPOSE_OP_PREVIOUS    0x02
-+
-+/* blend_op flags from inside fcTL */
-+#define PNG_BLEND_OP_SOURCE        0x00
-+#define PNG_BLEND_OP_OVER          0x01
-+#endif /* PNG_APNG_SUPPORTED */
-+
- /* This triggers a compiler error in png.c, if png.c and png.h
-  * do not agree upon the version number.
-  */
-@@ -750,6 +765,10 @@
- #define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
- #if INT_MAX >= 0x8000 /* else this might break */
- #define PNG_INFO_IDAT 0x8000   /* ESR, 1.0.6 */
-+#ifdef PNG_APNG_SUPPORTED
-+#define PNG_INFO_acTL 0x10000
-+#define PNG_INFO_fcTL 0x20000
+ libpng versions 1.0.7, July 1, 2000 through 1.6.22, May 26, 2016 are
+Index: pngread.c
+===================================================================
+--- pngread.c
++++ pngread.c
+@@ -158,6 +158,9 @@
+ 
+       else if (chunk_name == png_IDAT)
+       {
++#ifdef PNG_READ_APNG_SUPPORTED
++         png_have_info(png_ptr, info_ptr);
 +#endif
+          png_ptr->idat_size = length;
+          break;
+       }
+@@ -247,6 +250,17 @@
+          png_handle_iTXt(png_ptr, info_ptr, length);
  #endif
  
- /* This is used for the transformation routines, as some of them
-@@ -788,6 +807,10 @@
- #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
- typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
- typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
-+#ifdef PNG_APNG_SUPPORTED
-+typedef PNG_CALLBACK(void, *png_progressive_frame_ptr, (png_structp,
-+    png_uint_32));
++#ifdef PNG_READ_APNG_SUPPORTED
++      else if (chunk_name == png_acTL)
++         png_handle_acTL(png_ptr, info_ptr, length);
++
++      else if (chunk_name == png_fcTL)
++         png_handle_fcTL(png_ptr, info_ptr, length);
++
++      else if (chunk_name == png_fdAT)
++         png_handle_fdAT(png_ptr, info_ptr, length);
 +#endif
++
+       else
+          png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+@@ -254,6 +268,72 @@
+ }
+ #endif /* SEQUENTIAL_READ */
  
- /* The following callback receives png_uint_32 row_number, int pass for the
-  * png_bytep data of the row.  When transforming an interlaced image the
-@@ -3108,6 +3131,74 @@
- /*******************************************************************************
-  *  END OF HARDWARE AND SOFTWARE OPTIONS
-  ******************************************************************************/
-+#ifdef PNG_APNG_SUPPORTED
-+PNG_EXPORT(245, png_uint_32, png_get_acTL, (png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 *num_frames, png_uint_32 *num_plays));
++#ifdef PNG_READ_APNG_SUPPORTED
++void PNGAPI
++png_read_frame_head(png_structp png_ptr, png_infop info_ptr)
++{
++    png_byte have_chunk_after_DAT; /* after IDAT or after fdAT */
 +
-+PNG_EXPORT(246, png_uint_32, png_set_acTL, (png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 num_frames, png_uint_32 num_plays));
++    png_debug(0, "Reading frame head");
 +
-+PNG_EXPORT(247, png_uint_32, png_get_num_frames, (png_structp png_ptr,
-+   png_infop info_ptr));
++    if ((png_ptr->mode & PNG_HAVE_acTL) == 0)
++        png_error(png_ptr, "attempt to png_read_frame_head() but "
++                           "no acTL present");
 +
-+PNG_EXPORT(248, png_uint_32, png_get_num_plays, (png_structp png_ptr,
-+   png_infop info_ptr));
++    /* do nothing for the main IDAT */
++    if (png_ptr->num_frames_read == 0)
++        return;
 +
-+PNG_EXPORT(249, png_uint_32, png_get_next_frame_fcTL,
-+   (png_structp png_ptr, png_infop info_ptr, png_uint_32 *width,
-+   png_uint_32 *height, png_uint_32 *x_offset, png_uint_32 *y_offset,
-+   png_uint_16 *delay_num, png_uint_16 *delay_den, png_byte *dispose_op,
-+   png_byte *blend_op));
++    png_read_reset(png_ptr);
++    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
++    png_ptr->mode &= ~PNG_HAVE_fcTL;
 +
-+PNG_EXPORT(250, png_uint_32, png_set_next_frame_fcTL,
-+   (png_structp png_ptr, png_infop info_ptr, png_uint_32 width,
-+   png_uint_32 height, png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
-+   png_byte blend_op));
++    have_chunk_after_DAT = 0;
++    for (;;)
++    {
++        png_uint_32 length = png_read_chunk_header(png_ptr);
 +
-+PNG_EXPORT(251, png_uint_32, png_get_next_frame_width,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(252, png_uint_32, png_get_next_frame_height,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(253, png_uint_32, png_get_next_frame_x_offset,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(254, png_uint_32, png_get_next_frame_y_offset,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(255, png_uint_16, png_get_next_frame_delay_num,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(256, png_uint_16, png_get_next_frame_delay_den,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(257, png_byte, png_get_next_frame_dispose_op,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(258, png_byte, png_get_next_frame_blend_op,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(259, png_byte, png_get_first_frame_is_hidden,
-+   (png_structp png_ptr, png_infop info_ptr));
-+PNG_EXPORT(260, png_uint_32, png_set_first_frame_is_hidden,
-+   (png_structp png_ptr, png_infop info_ptr, png_byte is_hidden));
++        if (png_ptr->chunk_name == png_IDAT)
++        {
++            /* discard trailing IDATs for the first frame */
++            if (have_chunk_after_DAT != 0 || png_ptr->num_frames_read > 1)
++                png_error(png_ptr, "png_read_frame_head(): out of place IDAT");
++            png_crc_finish(png_ptr, length);
++        }
 +
-+#ifdef PNG_READ_APNG_SUPPORTED
-+PNG_EXPORT(261, void, png_read_frame_head, (png_structp png_ptr,
-+   png_infop info_ptr));
-+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-+PNG_EXPORT(262, void, png_set_progressive_frame_fn, (png_structp png_ptr,
-+   png_progressive_frame_ptr frame_info_fn,
-+   png_progressive_frame_ptr frame_end_fn));
-+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-+#endif /* PNG_READ_APNG_SUPPORTED */
++        else if (png_ptr->chunk_name == png_fcTL)
++        {
++            png_handle_fcTL(png_ptr, info_ptr, length);
++            have_chunk_after_DAT = 1;
++        }
 +
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+PNG_EXPORT(263, void, png_write_frame_head, (png_structp png_ptr,
-+   png_infop info_ptr, png_bytepp row_pointers,
-+   png_uint_32 width, png_uint_32 height,
-+   png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
-+   png_byte blend_op));
++        else if (png_ptr->chunk_name == png_fdAT)
++        {
++            png_ensure_sequence_number(png_ptr, length);
 +
-+PNG_EXPORT(264, void, png_write_frame_tail, (png_structp png_ptr,
-+   png_infop info_ptr));
-+#endif /* PNG_WRITE_APNG_SUPPORTED */
-+#endif /* PNG_APNG_SUPPORTED */
- 
- /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
-  * defs, and in scripts/symbols.def.
-@@ -3117,7 +3208,11 @@
-  * one to use is one more than this.)
-  */
- #ifdef PNG_EXPORT_LAST_ORDINAL
-+#ifdef PNG_APNG_SUPPORTED
-+  PNG_EXPORT_LAST_ORDINAL(264);
-+#else
-   PNG_EXPORT_LAST_ORDINAL(244);
-+#endif /* PNG_APNG_SUPPORTED */
- #endif
- 
- #ifdef __cplusplus
-diff -Naru libpng-1.6.19.org/pngget.c libpng-1.6.19/pngget.c
---- libpng-1.6.19.org/pngget.c	2015-11-15 22:34:42.408615513 +0900
-+++ libpng-1.6.19/pngget.c	2015-11-15 22:34:42.476617887 +0900
++            /* discard trailing fdATs for frames other than the first */
++            if (have_chunk_after_DAT == 0 && png_ptr->num_frames_read > 1)
++                png_crc_finish(png_ptr, length - 4);
++            else if(png_ptr->mode & PNG_HAVE_fcTL)
++            {
++                png_ptr->idat_size = length - 4;
++                png_ptr->mode |= PNG_HAVE_IDAT;
++
++                break;
++            }
++            else
++                png_error(png_ptr, "png_read_frame_head(): out of place fdAT");
++        }
++        else
++        {
++            png_warning(png_ptr, "Skipped (ignored) a chunk "
++                                 "between APNG chunks");
++            png_crc_finish(png_ptr, length);
++        }
++    }
++}
++#endif /* READ_APNG */
++
+ /* Optional call to update the users info_ptr structure */
+ void PNGAPI
+ png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
+Index: pngget.c
+===================================================================
+--- pngget.c
++++ pngget.c
 @@ -1216,4 +1216,166 @@
  #  endif
  #endif
@@ -154,7 +136,7 @@ diff -Naru libpng-1.6.19.org/pngget.c libpng-1.6.19/pngget.c
 +    png_debug1(1, "in %s retrieval function", "acTL");
 +
 +    if (png_ptr != NULL && info_ptr != NULL &&
-+        (info_ptr->valid & PNG_INFO_acTL) &&
++        (info_ptr->valid & PNG_INFO_acTL) != 0 &&
 +        num_frames != NULL && num_plays != NULL)
 +    {
 +        *num_frames = info_ptr->num_frames;
@@ -195,7 +177,7 @@ diff -Naru libpng-1.6.19.org/pngget.c libpng-1.6.19/pngget.c
 +    png_debug1(1, "in %s retrieval function", "fcTL");
 +
 +    if (png_ptr != NULL && info_ptr != NULL &&
-+        (info_ptr->valid & PNG_INFO_fcTL) &&
++        (info_ptr->valid & PNG_INFO_fcTL) != 0 &&
 +        width != NULL && height != NULL &&
 +        x_offset != NULL && y_offset != NULL &&
 +        delay_num != NULL && delay_den != NULL &&
@@ -307,11 +289,292 @@ diff -Naru libpng-1.6.19.org/pngget.c libpng-1.6.19/pngget.c
 +
 +    return 0;
 +}
-+#endif /* PNG_APNG_SUPPORTED */
++#endif /* APNG */
  #endif /* READ || WRITE */
-diff -Naru libpng-1.6.19.org/pnginfo.h libpng-1.6.19/pnginfo.h
---- libpng-1.6.19.org/pnginfo.h	2015-11-15 22:34:42.408615513 +0900
-+++ libpng-1.6.19/pnginfo.h	2015-11-15 22:34:42.477617922 +0900
+Index: png.c
+===================================================================
+--- png.c
++++ png.c
+@@ -775,17 +775,21 @@
+ #else
+ #  ifdef __STDC__
+    return PNG_STRING_NEWLINE \
+-      "libpng version 1.6.22 - May 26, 2016" PNG_STRING_NEWLINE \
++      "libpng version 1.6.22+apng - May 26, 2016" PNG_STRING_NEWLINE \
+       "Copyright (c) 1998-2002,2004,2006-2016 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;
++      PNG_STRING_NEWLINE \
++      "Portions Copyright (c) 2006-2007 Andrew Smith" PNG_STRING_NEWLINE \
++      "Portions Copyright (c) 2008-2016 Max Stepin" PNG_STRING_NEWLINE ;
+ #  else
+-   return "libpng version 1.6.22 - May 26, 2016\
++   return "libpng version 1.6.22+apng - May 26, 2016\
+       Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
+       Copyright (c) 1996-1997 Andreas Dilger\
+-      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
++      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\
++      Portions Copyright (c) 2006-2007 Andrew Smith\
++      Portions Copyright (c) 2008-2016 Max Stepin";
+ #  endif
+ #endif
+ }
+Index: png.h
+===================================================================
+--- png.h
++++ png.h
+@@ -23,6 +23,12 @@
+  * If you modify libpng you may insert additional notices immediately following
+  * this sentence.
+  *
++ * This modified version of libpng code adds animated PNG support and is
++ * released under the libpng license described below. The modifications are
++ * Copyright (c) 2006-2007 Andrew Smith, Copyright (c) 2008-2016 Max Stepin,
++ * and are delimited by "#ifdef PNG_APNG_SUPPORTED / #endif" directives
++ * surrounding them in the modified libpng source files.
++ *
+  * This code is released under the libpng license.
+  *
+  * Some files in the "contrib" directory and some configure-generated
+@@ -313,9 +319,9 @@
+  */
+ 
+ /* Version information for png.h - this should match the version in png.c */
+-#define PNG_LIBPNG_VER_STRING "1.6.22"
++#define PNG_LIBPNG_VER_STRING "1.6.22+apng"
+ #define PNG_HEADER_VERSION_STRING \
+-     " libpng version 1.6.22 - May 26, 2016\n"
++     " libpng version 1.6.22+apng - May 26, 2016\n"
+ 
+ #define PNG_LIBPNG_VER_SONUM   16
+ #define PNG_LIBPNG_VER_DLLNUM  16
+@@ -366,6 +372,10 @@
+ #   include "pnglibconf.h"
+ #endif
+ 
++#define PNG_APNG_SUPPORTED
++#define PNG_READ_APNG_SUPPORTED
++#define PNG_WRITE_APNG_SUPPORTED
++
+ #ifndef PNG_VERSION_INFO_ONLY
+    /* Machine specific configuration. */
+ #  include "pngconf.h"
+@@ -461,6 +471,17 @@
+  * See pngconf.h for base types that vary by machine/system
+  */
+ 
++#ifdef PNG_APNG_SUPPORTED
++/* dispose_op flags from inside fcTL */
++#define PNG_DISPOSE_OP_NONE        0x00
++#define PNG_DISPOSE_OP_BACKGROUND  0x01
++#define PNG_DISPOSE_OP_PREVIOUS    0x02
++
++/* blend_op flags from inside fcTL */
++#define PNG_BLEND_OP_SOURCE        0x00
++#define PNG_BLEND_OP_OVER          0x01
++#endif /* APNG */
++
+ /* This triggers a compiler error in png.c, if png.c and png.h
+  * do not agree upon the version number.
+  */
+@@ -781,6 +802,10 @@
+ #define PNG_INFO_sPLT 0x2000U  /* ESR, 1.0.6 */
+ #define PNG_INFO_sCAL 0x4000U  /* ESR, 1.0.6 */
+ #define PNG_INFO_IDAT 0x8000U  /* ESR, 1.0.6 */
++#ifdef PNG_APNG_SUPPORTED
++#define PNG_INFO_acTL 0x10000
++#define PNG_INFO_fcTL 0x20000
++#endif
+ 
+ /* This is used for the transformation routines, as some of them
+  * change these values for the row.  It also should enable using
+@@ -818,6 +843,10 @@
+ #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+ typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
+ typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
++#ifdef PNG_APNG_SUPPORTED
++typedef PNG_CALLBACK(void, *png_progressive_frame_ptr, (png_structp,
++    png_uint_32));
++#endif
+ 
+ /* The following callback receives png_uint_32 row_number, int pass for the
+  * png_bytep data of the row.  When transforming an interlaced image the
+@@ -3237,6 +3266,75 @@
+  *  END OF HARDWARE AND SOFTWARE OPTIONS
+  ******************************************************************************/
+ 
++#ifdef PNG_APNG_SUPPORTED
++PNG_EXPORT(245, png_uint_32, png_get_acTL, (png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 *num_frames, png_uint_32 *num_plays));
++
++PNG_EXPORT(246, png_uint_32, png_set_acTL, (png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 num_frames, png_uint_32 num_plays));
++
++PNG_EXPORT(247, png_uint_32, png_get_num_frames, (png_structp png_ptr,
++   png_infop info_ptr));
++
++PNG_EXPORT(248, png_uint_32, png_get_num_plays, (png_structp png_ptr,
++   png_infop info_ptr));
++
++PNG_EXPORT(249, png_uint_32, png_get_next_frame_fcTL,
++   (png_structp png_ptr, png_infop info_ptr, png_uint_32 *width,
++   png_uint_32 *height, png_uint_32 *x_offset, png_uint_32 *y_offset,
++   png_uint_16 *delay_num, png_uint_16 *delay_den, png_byte *dispose_op,
++   png_byte *blend_op));
++
++PNG_EXPORT(250, png_uint_32, png_set_next_frame_fcTL,
++   (png_structp png_ptr, png_infop info_ptr, png_uint_32 width,
++   png_uint_32 height, png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
++   png_byte blend_op));
++
++PNG_EXPORT(251, png_uint_32, png_get_next_frame_width,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(252, png_uint_32, png_get_next_frame_height,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(253, png_uint_32, png_get_next_frame_x_offset,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(254, png_uint_32, png_get_next_frame_y_offset,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(255, png_uint_16, png_get_next_frame_delay_num,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(256, png_uint_16, png_get_next_frame_delay_den,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(257, png_byte, png_get_next_frame_dispose_op,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(258, png_byte, png_get_next_frame_blend_op,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(259, png_byte, png_get_first_frame_is_hidden,
++   (png_structp png_ptr, png_infop info_ptr));
++PNG_EXPORT(260, png_uint_32, png_set_first_frame_is_hidden,
++   (png_structp png_ptr, png_infop info_ptr, png_byte is_hidden));
++
++#ifdef PNG_READ_APNG_SUPPORTED
++PNG_EXPORT(261, void, png_read_frame_head, (png_structp png_ptr,
++   png_infop info_ptr));
++#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
++PNG_EXPORT(262, void, png_set_progressive_frame_fn, (png_structp png_ptr,
++   png_progressive_frame_ptr frame_info_fn,
++   png_progressive_frame_ptr frame_end_fn));
++#endif /* PROGRESSIVE_READ */
++#endif /* READ_APNG */
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++PNG_EXPORT(263, void, png_write_frame_head, (png_structp png_ptr,
++   png_infop info_ptr, png_bytepp row_pointers,
++   png_uint_32 width, png_uint_32 height,
++   png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
++   png_byte blend_op));
++
++PNG_EXPORT(264, void, png_write_frame_tail, (png_structp png_ptr,
++   png_infop info_ptr));
++#endif /* WRITE_APNG */
++#endif /* APNG */
++
+ /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+  * defs, and in scripts/symbols.def.
+  */
+@@ -3245,7 +3343,11 @@
+  * one to use is one more than this.)
+  */
+ #ifdef PNG_EXPORT_LAST_ORDINAL
++#ifdef PNG_APNG_SUPPORTED
++  PNG_EXPORT_LAST_ORDINAL(265);
++#else
+   PNG_EXPORT_LAST_ORDINAL(245);
++#endif /* APNG */
+ #endif
+ 
+ #ifdef __cplusplus
+Index: pngpriv.h
+===================================================================
+--- pngpriv.h
++++ pngpriv.h
+@@ -537,6 +537,10 @@
+ #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+                    /*             0x4000 (unused) */
+ #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
++#ifdef PNG_APNG_SUPPORTED
++#define PNG_HAVE_acTL            0x10000
++#define PNG_HAVE_fcTL            0x20000
++#endif
+ 
+ /* Flags for the transformations the PNG library does on the image data */
+ #define PNG_BGR                 0x0001
+@@ -754,6 +758,16 @@
+ #define png_tRNS PNG_U32(116,  82,  78,  83)
+ #define png_zTXt PNG_U32(122,  84,  88, 116)
+ 
++#ifdef PNG_APNG_SUPPORTED
++#define png_acTL PNG_U32( 97,  99,  84,  76)
++#define png_fcTL PNG_U32(102,  99,  84,  76)
++#define png_fdAT PNG_U32(102, 100,  65,  84)
++
++/* For png_struct.apng_flags: */
++#define PNG_FIRST_FRAME_HIDDEN       0x0001
++#define PNG_APNG_APP                 0x0002
++#endif
++
+ /* The following will work on (signed char*) strings, whereas the get_uint_32
+  * macro will fail on top-bit-set values because of the sign extension.
+  */
+@@ -1441,6 +1455,49 @@
+ 
+ #endif /* PROGRESSIVE_READ */
+ 
++#ifdef PNG_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_ensure_fcTL_is_valid,(png_structp png_ptr,
++   png_uint_32 width, png_uint_32 height,
++   png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den,
++   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
++
++#ifdef PNG_READ_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_handle_acTL,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_handle_fcTL,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_handle_fdAT,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_have_info,(png_structp png_ptr,
++   png_infop info_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_ensure_sequence_number,(png_structp png_ptr,
++   png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_read_reset,(png_structp png_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_read_reinit,(png_structp png_ptr,
++   png_infop info_ptr),PNG_EMPTY);
++#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_progressive_read_reset,(png_structp png_ptr),
++   PNG_EMPTY);
++#endif /* PROGRESSIVE_READ */
++#endif /* READ_APNG */
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_write_acTL,(png_structp png_ptr,
++   png_uint_32 num_frames, png_uint_32 num_plays),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_fcTL,(png_structp png_ptr,
++   png_uint_32 width, png_uint_32 height,
++   png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den,
++   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_fdAT,(png_structp png_ptr,
++   png_const_bytep data, png_size_t length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_reset,(png_structp png_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_reinit,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 width, png_uint_32 height),PNG_EMPTY);
++#endif /* WRITE_APNG */
++#endif /* APNG */
++
+ /* Added at libpng version 1.6.0 */
+ #ifdef PNG_GAMMA_SUPPORTED
+ PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
+Index: pnginfo.h
+===================================================================
+--- pnginfo.h
++++ pnginfo.h
 @@ -255,5 +255,18 @@
     png_bytepp row_pointers;        /* the image bits */
  #endif
@@ -331,10 +594,113 @@ diff -Naru libpng-1.6.19.org/pnginfo.h libpng-1.6.19/pnginfo.h
 +
  };
  #endif /* PNGINFO_H */
-diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
---- libpng-1.6.19.org/pngpread.c	2015-11-15 22:34:42.409615548 +0900
-+++ libpng-1.6.19/pngpread.c	2015-11-15 22:34:42.477617922 +0900
-@@ -194,6 +194,106 @@
+Index: pngstruct.h
+===================================================================
+--- pngstruct.h
++++ pngstruct.h
+@@ -403,6 +403,27 @@
+    png_byte filter_type;
+ #endif
+ 
++#ifdef PNG_APNG_SUPPORTED
++   png_uint_32 apng_flags;
++   png_uint_32 next_seq_num;         /* next fcTL/fdAT chunk sequence number */
++   png_uint_32 first_frame_width;
++   png_uint_32 first_frame_height;
++
++#ifdef PNG_READ_APNG_SUPPORTED
++   png_uint_32 num_frames_read;      /* incremented after all image data of */
++                                     /* a frame is read */
++#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
++   png_progressive_frame_ptr frame_info_fn; /* frame info read callback */
++   png_progressive_frame_ptr frame_end_fn;  /* frame data read callback */
++#endif
++#endif
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   png_uint_32 num_frames_to_write;
++   png_uint_32 num_frames_written;
++#endif
++#endif /* APNG */
++
+ /* New members added in libpng-1.2.0 */
+ 
+ /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+Index: pngwrite.c
+===================================================================
+--- pngwrite.c
++++ pngwrite.c
+@@ -128,6 +128,10 @@
+        * the application continues writing the PNG.  So check the 'invalid'
+        * flag here too.
+        */
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   if ((info_ptr->valid & PNG_INFO_acTL) != 0)
++      png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
++#endif
+ #ifdef PNG_GAMMA_SUPPORTED
+ #  ifdef PNG_WRITE_gAMA_SUPPORTED
+       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+@@ -360,6 +364,11 @@
+    if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+       png_error(png_ptr, "No IDATs written into file");
+ 
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
++      png_error(png_ptr, "Not enough frames written");
++#endif
++
+ #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+    if (png_ptr->num_palette_max > png_ptr->num_palette)
+       png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
+@@ -2380,4 +2389,42 @@
+ }
+ #endif /* SIMPLIFIED_WRITE_STDIO */
+ #endif /* SIMPLIFIED_WRITE */
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++void PNGAPI
++png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
++    png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
++    png_byte blend_op)
++{
++    png_debug(1, "in png_write_frame_head");
++
++    /* there is a chance this has been set after png_write_info was called,
++    * so it would be set but not written. is there a way to be sure? */
++    if ((info_ptr->valid & PNG_INFO_acTL) == 0)
++        png_error(png_ptr, "png_write_frame_head(): acTL not set");
++
++    png_write_reset(png_ptr);
++
++    png_write_reinit(png_ptr, info_ptr, width, height);
++
++    if ((png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) == 0 ||
++        png_ptr->num_frames_written != 0)
++        png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
++                       delay_num, delay_den, dispose_op, blend_op);
++
++    PNG_UNUSED(row_pointers)
++}
++
++void PNGAPI
++png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
++{
++    png_debug(1, "in png_write_frame_tail");
++
++    png_ptr->num_frames_written++;
++
++    PNG_UNUSED(info_ptr)
++}
++#endif /* WRITE_APNG */
+ #endif /* WRITE */
+Index: pngpread.c
+===================================================================
+--- pngpread.c
++++ pngpread.c
+@@ -194,6 +194,89 @@
  
     chunk_name = png_ptr->chunk_name;
  
@@ -345,42 +711,29 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
 +      if (chunk_name == png_IDAT)
 +      {
 +         /* Discard trailing IDATs for the first frame */
-+         if (png_ptr->mode & PNG_HAVE_fcTL || png_ptr->num_frames_read > 1)
++         if ((png_ptr->mode & PNG_HAVE_fcTL) != 0 ||
++             png_ptr->num_frames_read > 1)
 +            png_error(png_ptr, "out of place IDAT");
 +
-+         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+         {
-+            png_push_save_buffer(png_ptr);
-+            return;
-+         }
-+
++         PNG_PUSH_SAVE_BUFFER_IF_FULL
++         png_crc_finish(png_ptr, png_ptr->push_length);
 +         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-+         return;
 +      }
++
 +      else if (chunk_name == png_fdAT)
 +      {
-+         if (png_ptr->buffer_size < 4)
-+         {
-+            png_push_save_buffer(png_ptr);
-+            return;
-+         }
-+
++         PNG_PUSH_SAVE_BUFFER_IF_LT(4)
 +         png_ensure_sequence_number(png_ptr, 4);
 +
-+         if (!(png_ptr->mode & PNG_HAVE_fcTL))
++         if ((png_ptr->mode & PNG_HAVE_fcTL) == 0)
 +         {
 +            /* Discard trailing fdATs for frames other than the first */
 +            if (png_ptr->num_frames_read < 2)
 +               png_error(png_ptr, "out of place fdAT");
 +
-+            if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+            {
-+               png_push_save_buffer(png_ptr);
-+               return;
-+            }
-+
++            PNG_PUSH_SAVE_BUFFER_IF_FULL
++            png_crc_finish(png_ptr, png_ptr->push_length);
 +            png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-+            return;
 +         }
 +
 +         else
@@ -389,25 +742,18 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
 +            png_ptr->idat_size = png_ptr->push_length - 4;
 +            png_ptr->mode |= PNG_HAVE_IDAT;
 +            png_ptr->process_mode = PNG_READ_IDAT_MODE;
-+
-+            return;
 +         }
 +      }
 +
 +      else if (chunk_name == png_fcTL)
 +      {
-+         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+         {
-+            png_push_save_buffer(png_ptr);
-+            return;
-+         }
-+
++         PNG_PUSH_SAVE_BUFFER_IF_FULL
 +         png_read_reset(png_ptr);
 +         png_ptr->mode &= ~PNG_HAVE_fcTL;
 +
 +         png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
 +
-+         if (!(png_ptr->mode & PNG_HAVE_fcTL))
++         if ((png_ptr->mode & PNG_HAVE_fcTL) == 0)
 +            png_error(png_ptr, "missing required fcTL chunk");
 +
 +         png_read_reinit(png_ptr, info_ptr);
@@ -417,31 +763,34 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
 +            (*(png_ptr->frame_info_fn))(png_ptr, png_ptr->num_frames_read);
 +
 +         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
++      }
 +
-+         return;
++      else if (chunk_name == png_IEND)
++      {
++         PNG_PUSH_SAVE_BUFFER_IF_FULL
++         png_warning(png_ptr, "Number of actual frames fewer than expected");
++         png_crc_finish(png_ptr, png_ptr->push_length);
++         png_ptr->process_mode = PNG_READ_DONE_MODE;
++         png_push_have_end(png_ptr, info_ptr);
 +      }
 +
 +      else
 +      {
-+         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+         {
-+            png_push_save_buffer(png_ptr);
-+            return;
-+         }
++         PNG_PUSH_SAVE_BUFFER_IF_FULL
 +         png_warning(png_ptr, "Skipped (ignored) a chunk "
 +                              "between APNG chunks");
++         png_crc_finish(png_ptr, png_ptr->push_length);
 +         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-+         return;
 +      }
 +
 +      return;
 +   }
-+#endif /* PNG_READ_APNG_SUPPORTED */
++#endif /* READ_APNG */
 +
     if (chunk_name == png_IDAT)
     {
        if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
-@@ -258,6 +358,9 @@
+@@ -258,6 +341,9 @@
  
     else if (chunk_name == png_IDAT)
     {
@@ -451,38 +800,28 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
        png_ptr->idat_size = png_ptr->push_length;
        png_ptr->process_mode = PNG_READ_IDAT_MODE;
        png_push_have_info(png_ptr, info_ptr);
-@@ -403,6 +506,30 @@
-       png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+@@ -404,6 +490,20 @@
     }
  #endif
+ 
 +#ifdef PNG_READ_APNG_SUPPORTED
 +   else if (chunk_name == png_acTL)
 +   {
-+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+      {
-+         png_push_save_buffer(png_ptr);
-+         return;
-+      }
-+
++      PNG_PUSH_SAVE_BUFFER_IF_FULL
 +      png_handle_acTL(png_ptr, info_ptr, png_ptr->push_length);
 +   }
 +
 +   else if (chunk_name == png_fcTL)
 +   {
-+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+      {
-+         png_push_save_buffer(png_ptr);
-+         return;
-+      }
-+
++      PNG_PUSH_SAVE_BUFFER_IF_FULL
 +      png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
 +   }
 +
-+#endif /* PNG_READ_APNG_SUPPORTED */
- 
++#endif /* READ_APNG */
     else
     {
-@@ -533,7 +660,11 @@
+       PNG_PUSH_SAVE_BUFFER_IF_FULL
+@@ -533,7 +633,11 @@
        png_byte chunk_tag[4];
  
        /* TODO: this code can be commoned up with the same code in push_read */
@@ -494,14 +833,14 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
        png_push_fill_buffer(png_ptr, chunk_length, 4);
        png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
        png_reset_crc(png_ptr);
-@@ -541,17 +672,64 @@
+@@ -541,17 +645,60 @@
        png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
        png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
  
 +#ifdef PNG_READ_APNG_SUPPORTED
 +      if (png_ptr->chunk_name != png_fdAT && png_ptr->num_frames_read > 0)
 +      {
-+          if (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)
++          if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) != 0)
 +          {
 +              png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 +              if (png_ptr->frame_end_fn != NULL)
@@ -513,11 +852,7 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
 +          {
 +              if (png_ptr->chunk_name == png_IEND)
 +                  png_error(png_ptr, "Not enough image data");
-+              if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-+              {
-+                 png_push_save_buffer(png_ptr);
-+                 return;
-+              }
++              PNG_PUSH_SAVE_BUFFER_IF_FULL
 +              png_warning(png_ptr, "Skipping (ignoring) a chunk between "
 +                                   "APNG chunks");
 +              png_crc_finish(png_ptr, png_ptr->push_length);
@@ -559,23 +894,24 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
     }
  
     if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
-@@ -625,6 +803,15 @@
+@@ -625,6 +772,16 @@
     if (!(buffer_length > 0) || buffer == NULL)
        png_error(png_ptr, "No IDAT data (internal error)");
  
 +#ifdef PNG_READ_APNG_SUPPORTED
 +   /* If the app is not APNG-aware, decode only the first frame */
-+   if (!(png_ptr->apng_flags & PNG_APNG_APP) && png_ptr->num_frames_read > 0)
++   if ((png_ptr->apng_flags & PNG_APNG_APP) == 0 &&
++      png_ptr->num_frames_read > 0)
 +   {
-+     png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
-+     return;
++      png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
++      return;
 +   }
 +#endif
 +
     /* This routine must process all the data it has been given
      * before returning, calling the row callback as required to
      * handle the uncompressed results.
-@@ -1074,6 +1261,18 @@
+@@ -1074,6 +1231,18 @@
     png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
  }
  
@@ -594,193 +930,174 @@ diff -Naru libpng-1.6.19.org/pngpread.c libpng-1.6.19/pngpread.c
  png_voidp PNGAPI
  png_get_progressive_ptr(png_const_structrp png_ptr)
  {
-diff -Naru libpng-1.6.19.org/pngpriv.h libpng-1.6.19/pngpriv.h
---- libpng-1.6.19.org/pngpriv.h	2015-11-15 22:34:42.409615548 +0900
-+++ libpng-1.6.19/pngpriv.h	2015-11-15 22:34:42.477617922 +0900
-@@ -537,6 +537,10 @@
- #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
-                    /*             0x4000 (unused) */
- #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
+Index: pngset.c
+===================================================================
+--- pngset.c
++++ pngset.c
+@@ -241,6 +241,11 @@
+    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+ 
+    info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
++
 +#ifdef PNG_APNG_SUPPORTED
-+#define PNG_HAVE_acTL            0x10000
-+#define PNG_HAVE_fcTL            0x20000
++   /* for non-animated png. this may be overwritten from an acTL chunk later */
++   info_ptr->num_frames = 1;
 +#endif
+ }
  
- /* Flags for the transformations the PNG library does on the image data */
- #define PNG_BGR                 0x0001
-@@ -754,6 +758,16 @@
- #define png_tRNS PNG_U32(116,  82,  78,  83)
- #define png_zTXt PNG_U32(122,  84,  88, 116)
+ #ifdef PNG_oFFs_SUPPORTED
+@@ -1094,6 +1099,146 @@
+ }
+ #endif /* sPLT */
  
 +#ifdef PNG_APNG_SUPPORTED
-+#define png_acTL PNG_U32( 97,  99,  84,  76)
-+#define png_fcTL PNG_U32(102,  99,  84,  76)
-+#define png_fdAT PNG_U32(102, 100,  65,  84)
++png_uint_32 PNGAPI
++png_set_acTL(png_structp png_ptr, png_infop info_ptr,
++    png_uint_32 num_frames, png_uint_32 num_plays)
++{
++    png_debug1(1, "in %s storage function", "acTL");
 +
-+/* For png_struct.apng_flags: */
-+#define PNG_FIRST_FRAME_HIDDEN       0x0001
-+#define PNG_APNG_APP                 0x0002
-+#endif
++    if (png_ptr == NULL || info_ptr == NULL)
++    {
++        png_warning(png_ptr,
++                    "Call to png_set_acTL() with NULL png_ptr "
++                    "or info_ptr ignored");
++        return (0);
++    }
++    if (num_frames == 0)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_frames zero");
++        return (0);
++    }
++    if (num_frames > PNG_UINT_31_MAX)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_frames > 2^31-1");
++        return (0);
++    }
++    if (num_plays > PNG_UINT_31_MAX)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_plays > 2^31-1");
++        return (0);
++    }
 +
- /* The following will work on (signed char*) strings, whereas the get_uint_32
-  * macro will fail on top-bit-set values because of the sign extension.
-  */
-@@ -1453,6 +1467,47 @@
-      */
- #endif
- 
-+#ifdef PNG_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_ensure_fcTL_is_valid,(png_structp png_ptr,
-+   png_uint_32 width, png_uint_32 height,
-+   png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den,
-+   png_byte dispose_op, png_byte blend_op), PNG_EMPTY);
++    info_ptr->num_frames = num_frames;
++    info_ptr->num_plays = num_plays;
 +
-+#ifdef PNG_READ_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_handle_acTL,(png_structp png_ptr, png_infop info_ptr,
-+   png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_handle_fcTL,(png_structp png_ptr, png_infop info_ptr,
-+   png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_handle_fdAT,(png_structp png_ptr, png_infop info_ptr,
-+   png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_have_info,(png_structp png_ptr, png_infop info_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_ensure_sequence_number,(png_structp png_ptr,
-+   png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_read_reset,(png_structp png_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_read_reinit,(png_structp png_ptr,
-+   png_infop info_ptr),PNG_EMPTY);
-+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_progressive_read_reset,(png_structp png_ptr),PNG_EMPTY);
-+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-+#endif /* PNG_READ_APNG_SUPPORTED */
++    info_ptr->valid |= PNG_INFO_acTL;
 +
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_write_acTL,(png_structp png_ptr,
-+   png_uint_32 num_frames, png_uint_32 num_plays),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_fcTL,(png_structp png_ptr,
-+   png_uint_32 width, png_uint_32 height,
-+   png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den,
-+   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_fdAT,(png_structp png_ptr,
-+   png_const_bytep data, png_size_t length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_reset,(png_structp png_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_reinit,(png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 width, png_uint_32 height),PNG_EMPTY);
-+#endif /* PNG_WRITE_APNG_SUPPORTED */
-+#endif /* PNG_APNG_SUPPORTED */
-+
- /* Added at libpng version 1.4.0 */
- #ifdef PNG_COLORSPACE_SUPPORTED
- /* These internal functions are for maintaining the colorspace structure within
-diff -Naru libpng-1.6.19.org/pngread.c libpng-1.6.19/pngread.c
---- libpng-1.6.19.org/pngread.c	2015-11-15 22:34:42.410615583 +0900
-+++ libpng-1.6.19/pngread.c	2015-11-15 22:34:42.478617957 +0900
-@@ -158,6 +158,9 @@
- 
-       else if (chunk_name == png_IDAT)
-       {
-+#ifdef PNG_READ_APNG_SUPPORTED
-+         png_have_info(png_ptr, info_ptr);
-+#endif
-          png_ptr->idat_size = length;
-          break;
-       }
-@@ -247,6 +250,17 @@
-          png_handle_iTXt(png_ptr, info_ptr, length);
- #endif
- 
-+#ifdef PNG_READ_APNG_SUPPORTED
-+      else if (chunk_name == png_acTL)
-+         png_handle_acTL(png_ptr, info_ptr, length);
++    return (1);
++}
 +
-+      else if (chunk_name == png_fcTL)
-+         png_handle_fcTL(png_ptr, info_ptr, length);
++/* delay_num and delay_den can hold any 16-bit values including zero */
++png_uint_32 PNGAPI
++png_set_next_frame_fcTL(png_structp png_ptr, png_infop info_ptr,
++    png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den,
++    png_byte dispose_op, png_byte blend_op)
++{
++    png_debug1(1, "in %s storage function", "fcTL");
 +
-+      else if (chunk_name == png_fdAT)
-+         png_handle_fdAT(png_ptr, info_ptr, length);
-+#endif
++    if (png_ptr == NULL || info_ptr == NULL)
++    {
++        png_warning(png_ptr,
++                    "Call to png_set_fcTL() with NULL png_ptr or info_ptr "
++                    "ignored");
++        return (0);
++    }
 +
-       else
-          png_handle_unknown(png_ptr, info_ptr, length,
-             PNG_HANDLE_CHUNK_AS_DEFAULT);
-@@ -254,6 +268,72 @@
- }
- #endif /* SEQUENTIAL_READ */
- 
-+#ifdef PNG_READ_APNG_SUPPORTED
-+void PNGAPI
-+png_read_frame_head(png_structp png_ptr, png_infop info_ptr)
-+{
-+    png_byte have_chunk_after_DAT; /* after IDAT or after fdAT */
++    png_ensure_fcTL_is_valid(png_ptr, width, height, x_offset, y_offset,
++                             delay_num, delay_den, dispose_op, blend_op);
 +
-+    png_debug(0, "Reading frame head");
++    if (blend_op == PNG_BLEND_OP_OVER)
++    {
++        if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0 &&
++            png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) == 0)
++        {
++          png_warning(png_ptr, "PNG_BLEND_OP_OVER is meaningless "
++                               "and wasteful for opaque images, ignored");
++          blend_op = PNG_BLEND_OP_SOURCE;
++        }
++    }
 +
-+    if (!(png_ptr->mode & PNG_HAVE_acTL))
-+        png_error(png_ptr, "attempt to png_read_frame_head() but "
-+                           "no acTL present");
++    info_ptr->next_frame_width = width;
++    info_ptr->next_frame_height = height;
++    info_ptr->next_frame_x_offset = x_offset;
++    info_ptr->next_frame_y_offset = y_offset;
++    info_ptr->next_frame_delay_num = delay_num;
++    info_ptr->next_frame_delay_den = delay_den;
++    info_ptr->next_frame_dispose_op = dispose_op;
++    info_ptr->next_frame_blend_op = blend_op;
 +
-+    /* do nothing for the main IDAT */
-+    if (png_ptr->num_frames_read == 0)
-+        return;
++    info_ptr->valid |= PNG_INFO_fcTL;
 +
-+    png_read_reset(png_ptr);
-+    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-+    png_ptr->mode &= ~PNG_HAVE_fcTL;
++    return (1);
++}
 +
-+    have_chunk_after_DAT = 0;
-+    for (;;)
-+    {
-+        png_uint_32 length = png_read_chunk_header(png_ptr);
++void /* PRIVATE */
++png_ensure_fcTL_is_valid(png_structp png_ptr,
++    png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den,
++    png_byte dispose_op, png_byte blend_op)
++{
++    if (width > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid width in fcTL (> 2^31-1)");
++    if (height > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid height in fcTL (> 2^31-1)");
++    if (x_offset > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid x_offset in fcTL (> 2^31-1)");
++    if (y_offset > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid y_offset in fcTL (> 2^31-1)");
++    if (width + x_offset > png_ptr->first_frame_width ||
++        height + y_offset > png_ptr->first_frame_height)
++        png_error(png_ptr, "dimensions of a frame are greater than "
++                           "the ones in IHDR");
 +
-+        if (png_ptr->chunk_name == png_IDAT)
-+        {
-+            /* discard trailing IDATs for the first frame */
-+            if (have_chunk_after_DAT || png_ptr->num_frames_read > 1)
-+                png_error(png_ptr, "png_read_frame_head(): out of place IDAT");
-+            png_crc_finish(png_ptr, length);
-+        }
++    if (dispose_op != PNG_DISPOSE_OP_NONE &&
++        dispose_op != PNG_DISPOSE_OP_BACKGROUND &&
++        dispose_op != PNG_DISPOSE_OP_PREVIOUS)
++        png_error(png_ptr, "invalid dispose_op in fcTL");
 +
-+        else if (png_ptr->chunk_name == png_fcTL)
-+        {
-+            png_handle_fcTL(png_ptr, info_ptr, length);
-+            have_chunk_after_DAT = 1;
-+        }
++    if (blend_op != PNG_BLEND_OP_SOURCE &&
++        blend_op != PNG_BLEND_OP_OVER)
++        png_error(png_ptr, "invalid blend_op in fcTL");
 +
-+        else if (png_ptr->chunk_name == png_fdAT)
-+        {
-+            png_ensure_sequence_number(png_ptr, length);
++    PNG_UNUSED(delay_num)
++    PNG_UNUSED(delay_den)
++}
 +
-+            /* discard trailing fdATs for frames other than the first */
-+            if (!have_chunk_after_DAT && png_ptr->num_frames_read > 1)
-+                png_crc_finish(png_ptr, length - 4);
-+            else if(png_ptr->mode & PNG_HAVE_fcTL)
-+            {
-+                png_ptr->idat_size = length - 4;
-+                png_ptr->mode |= PNG_HAVE_IDAT;
++png_uint_32 PNGAPI
++png_set_first_frame_is_hidden(png_structp png_ptr, png_infop info_ptr,
++                              png_byte is_hidden)
++{
++    png_debug(1, "in png_first_frame_is_hidden()");
 +
-+                break;
-+            }
-+            else
-+                png_error(png_ptr, "png_read_frame_head(): out of place fdAT");
-+        }
-+        else
-+        {
-+            png_warning(png_ptr, "Skipped (ignored) a chunk "
-+                                 "between APNG chunks");
-+            png_crc_finish(png_ptr, length);
-+        }
-+    }
++    if (png_ptr == NULL)
++        return 0;
++
++    if (is_hidden != 0)
++        png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
++    else
++        png_ptr->apng_flags &= ~PNG_FIRST_FRAME_HIDDEN;
++
++    PNG_UNUSED(info_ptr)
++
++    return 1;
 +}
-+#endif /* PNG_READ_APNG_SUPPORTED */
++#endif /* APNG */
 +
- /* Optional call to update the users info_ptr structure */
- void PNGAPI
- png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
-diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
---- libpng-1.6.19.org/pngrutil.c	2015-11-15 22:34:42.412615653 +0900
-+++ libpng-1.6.19/pngrutil.c	2015-11-15 22:34:42.480618027 +0900
-@@ -824,6 +824,11 @@
+ #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ static png_byte
+ check_location(png_const_structrp png_ptr, int location)
+Index: pngrutil.c
+===================================================================
+--- pngrutil.c
++++ pngrutil.c
+@@ -855,6 +855,11 @@
     filter_type = buf[11];
     interlace_type = buf[12];
  
@@ -792,7 +1109,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
     /* Set internal variables */
     png_ptr->width = width;
     png_ptr->height = height;
-@@ -2724,6 +2729,179 @@
+@@ -2755,6 +2760,180 @@
  }
  #endif
  
@@ -807,17 +1124,17 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +
 +    png_debug(1, "in png_handle_acTL");
 +
-+    if (!(png_ptr->mode & PNG_HAVE_IHDR))
++    if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
 +    {
 +        png_error(png_ptr, "Missing IHDR before acTL");
 +    }
-+    else if (png_ptr->mode & PNG_HAVE_IDAT)
++    else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
 +    {
 +        png_warning(png_ptr, "Invalid acTL after IDAT skipped");
 +        png_crc_finish(png_ptr, length);
 +        return;
 +    }
-+    else if (png_ptr->mode & PNG_HAVE_acTL)
++    else if ((png_ptr->mode & PNG_HAVE_acTL) != 0)
 +    {
 +        png_warning(png_ptr, "Duplicate acTL skipped");
 +        png_crc_finish(png_ptr, length);
@@ -838,7 +1155,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +
 +    /* the set function will do error checking on num_frames */
 +    didSet = png_set_acTL(png_ptr, info_ptr, num_frames, num_plays);
-+    if(didSet)
++    if (didSet != 0)
 +        png_ptr->mode |= PNG_HAVE_acTL;
 +}
 +
@@ -859,11 +1176,11 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +
 +    png_ensure_sequence_number(png_ptr, length);
 +
-+    if (!(png_ptr->mode & PNG_HAVE_IHDR))
++    if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
 +    {
 +        png_error(png_ptr, "Missing IHDR before fcTL");
 +    }
-+    else if (png_ptr->mode & PNG_HAVE_IDAT)
++    else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
 +    {
 +        /* for any frames other then the first this message may be misleading,
 +        * but correct. PNG_HAVE_IDAT is unset before the frame head is read
@@ -872,7 +1189,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +        png_crc_finish(png_ptr, length-4);
 +        return;
 +    }
-+    else if (png_ptr->mode & PNG_HAVE_fcTL)
++    else if ((png_ptr->mode & PNG_HAVE_fcTL) != 0)
 +    {
 +        png_warning(png_ptr, "Duplicate fcTL within one frame skipped");
 +        png_crc_finish(png_ptr, length-4);
@@ -927,7 +1244,8 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +void /* PRIVATE */
 +png_have_info(png_structp png_ptr, png_infop info_ptr)
 +{
-+    if((info_ptr->valid & PNG_INFO_acTL) && !(info_ptr->valid & PNG_INFO_fcTL))
++    if ((info_ptr->valid & PNG_INFO_acTL) != 0 &&
++        (info_ptr->valid & PNG_INFO_fcTL) == 0)
 +    {
 +        png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
 +        info_ptr->num_frames++;
@@ -967,15 +1285,15 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +
 +    png_ptr->next_seq_num++;
 +}
-+#endif /* PNG_READ_APNG_SUPPORTED */
++#endif /* READ_APNG */
 +
  #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
  /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
  static int
-@@ -3982,7 +4160,38 @@
-       {
+@@ -4014,6 +4193,38 @@
           uInt avail_in;
           png_bytep buffer;
+ 
 +#ifdef PNG_READ_APNG_SUPPORTED
 +         png_uint_32 bytes_to_skip = 0;
 +
@@ -1001,7 +1319,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +                  bytes_to_skip = png_ptr->idat_size;
 +                  continue;
 +               }
- 
++
 +               png_ensure_sequence_number(png_ptr, png_ptr->idat_size);
 +
 +               png_ptr->idat_size -= 4;
@@ -1011,16 +1329,15 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
           while (png_ptr->idat_size == 0)
           {
              png_crc_finish(png_ptr, 0);
-@@ -3994,7 +4203,7 @@
+@@ -4025,6 +4236,7 @@
              if (png_ptr->chunk_name != png_IDAT)
                 png_error(png_ptr, "Not enough image data");
           }
--
-+#endif /* PNG_READ_APNG_SUPPORTED */
++#endif /* READ_APNG */
+ 
           avail_in = png_ptr->IDAT_read_size;
  
-          if (avail_in > png_ptr->idat_size)
-@@ -4057,6 +4266,9 @@
+@@ -4088,6 +4300,9 @@
  
           png_ptr->mode |= PNG_AFTER_IDAT;
           png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
@@ -1030,7 +1347,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
  
           if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
              png_chunk_benign_error(png_ptr, "Extra compressed data");
-@@ -4495,4 +4707,80 @@
+@@ -4526,4 +4741,80 @@
  
     png_ptr->flags |= PNG_FLAG_ROW_INIT;
  }
@@ -1056,7 +1373,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +    png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->width);
 +    png_ptr->info_rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,
 +        png_ptr->width);
-+    if (png_ptr->prev_row)
++    if (png_ptr->prev_row != NULL)
 +        memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
 +}
 +
@@ -1066,23 +1383,23 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +png_progressive_read_reset(png_structp png_ptr)
 +{
 +#ifdef PNG_READ_INTERLACING_SUPPORTED
-+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
++    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 +
-+   /* Start of interlace block */
-+    const int png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
++    /* Start of interlace block */
++    static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 +
 +    /* Offset to next interlace block */
-+    const int png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
++    static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 +
 +    /* Start of interlace block in the y direction */
-+    const int png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
++    static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 +
 +    /* Offset to next interlace block in the y direction */
-+    const int png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
++    static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 +
-+    if (png_ptr->interlaced)
++    if (png_ptr->interlaced != 0)
 +    {
-+        if (!(png_ptr->transformations & PNG_INTERLACE))
++        if ((png_ptr->transformations & PNG_INTERLACE) == 0)
 +            png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
 +                                png_pass_ystart[0]) / png_pass_yinc[0];
 +        else
@@ -1094,7 +1411,7 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +                           png_pass_inc[png_ptr->pass];
 +    }
 +    else
-+#endif /* PNG_READ_INTERLACING_SUPPORTED */
++#endif /* READ_INTERLACING */
 +    {
 +        png_ptr->num_rows = png_ptr->height;
 +        png_ptr->iwidth = png_ptr->width;
@@ -1108,277 +1425,14 @@ diff -Naru libpng-1.6.19.org/pngrutil.c libpng-1.6.19/pngrutil.c
 +    png_ptr->zstream.avail_out = (uInt)PNG_ROWBYTES(png_ptr->pixel_depth,
 +        png_ptr->iwidth) + 1;
 +}
-+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-+#endif /* PNG_READ_APNG_SUPPORTED */
++#endif /* PROGRESSIVE_READ */
++#endif /* READ_APNG */
  #endif /* READ */
-diff -Naru libpng-1.6.19.org/pngset.c libpng-1.6.19/pngset.c
---- libpng-1.6.19.org/pngset.c	2015-11-15 22:34:42.412615653 +0900
-+++ libpng-1.6.19/pngset.c	2015-11-15 22:34:42.480618027 +0900
-@@ -241,6 +241,11 @@
-    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
- 
-    info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
-+
-+#ifdef PNG_APNG_SUPPORTED
-+   /* for non-animated png. this may be overwritten from an acTL chunk later */
-+   info_ptr->num_frames = 1;
-+#endif
- }
- 
- #ifdef PNG_oFFs_SUPPORTED
-@@ -1094,6 +1099,147 @@
- }
- #endif /* sPLT */
- 
-+#ifdef PNG_APNG_SUPPORTED
-+png_uint_32 PNGAPI
-+png_set_acTL(png_structp png_ptr, png_infop info_ptr,
-+    png_uint_32 num_frames, png_uint_32 num_plays)
-+{
-+    png_debug1(1, "in %s storage function", "acTL");
-+
-+    if (png_ptr == NULL || info_ptr == NULL)
-+    {
-+        png_warning(png_ptr,
-+                    "Call to png_set_acTL() with NULL png_ptr "
-+                    "or info_ptr ignored");
-+        return (0);
-+    }
-+    if (num_frames == 0)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_frames zero");
-+        return (0);
-+    }
-+    if (num_frames > PNG_UINT_31_MAX)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_frames > 2^31-1");
-+        return (0);
-+    }
-+    if (num_plays > PNG_UINT_31_MAX)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_plays "
-+                    "> 2^31-1");
-+        return (0);
-+    }
-+
-+    info_ptr->num_frames = num_frames;
-+    info_ptr->num_plays = num_plays;
-+
-+    info_ptr->valid |= PNG_INFO_acTL;
-+
-+    return (1);
-+}
-+
-+/* delay_num and delay_den can hold any 16-bit values including zero */
-+png_uint_32 PNGAPI
-+png_set_next_frame_fcTL(png_structp png_ptr, png_infop info_ptr,
-+    png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den,
-+    png_byte dispose_op, png_byte blend_op)
-+{
-+    png_debug1(1, "in %s storage function", "fcTL");
-+
-+    if (png_ptr == NULL || info_ptr == NULL)
-+    {
-+        png_warning(png_ptr,
-+                    "Call to png_set_fcTL() with NULL png_ptr or info_ptr "
-+                    "ignored");
-+        return (0);
-+    }
-+
-+    png_ensure_fcTL_is_valid(png_ptr, width, height, x_offset, y_offset,
-+                             delay_num, delay_den, dispose_op, blend_op);
-+
-+    if (blend_op == PNG_BLEND_OP_OVER)
-+    {
-+        if (!(png_ptr->color_type & PNG_COLOR_MASK_ALPHA) &&
-+            !(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
-+        {
-+          png_warning(png_ptr, "PNG_BLEND_OP_OVER is meaningless "
-+                               "and wasteful for opaque images, ignored");
-+          blend_op = PNG_BLEND_OP_SOURCE;
-+        }
-+    }
-+
-+    info_ptr->next_frame_width = width;
-+    info_ptr->next_frame_height = height;
-+    info_ptr->next_frame_x_offset = x_offset;
-+    info_ptr->next_frame_y_offset = y_offset;
-+    info_ptr->next_frame_delay_num = delay_num;
-+    info_ptr->next_frame_delay_den = delay_den;
-+    info_ptr->next_frame_dispose_op = dispose_op;
-+    info_ptr->next_frame_blend_op = blend_op;
-+
-+    info_ptr->valid |= PNG_INFO_fcTL;
-+
-+    return (1);
-+}
-+
-+void /* PRIVATE */
-+png_ensure_fcTL_is_valid(png_structp png_ptr,
-+    png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den,
-+    png_byte dispose_op, png_byte blend_op)
-+{
-+    if (width > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid width in fcTL (> 2^31-1)");
-+    if (height > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid height in fcTL (> 2^31-1)");
-+    if (x_offset > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid x_offset in fcTL (> 2^31-1)");
-+    if (y_offset > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid y_offset in fcTL (> 2^31-1)");
-+    if (width + x_offset > png_ptr->first_frame_width ||
-+        height + y_offset > png_ptr->first_frame_height)
-+        png_error(png_ptr, "dimensions of a frame are greater than"
-+                           "the ones in IHDR");
-+
-+    if (dispose_op != PNG_DISPOSE_OP_NONE &&
-+        dispose_op != PNG_DISPOSE_OP_BACKGROUND &&
-+        dispose_op != PNG_DISPOSE_OP_PREVIOUS)
-+        png_error(png_ptr, "invalid dispose_op in fcTL");
-+
-+    if (blend_op != PNG_BLEND_OP_SOURCE &&
-+        blend_op != PNG_BLEND_OP_OVER)
-+        png_error(png_ptr, "invalid blend_op in fcTL");
-+
-+    PNG_UNUSED(delay_num)
-+    PNG_UNUSED(delay_den)
-+}
-+
-+png_uint_32 PNGAPI
-+png_set_first_frame_is_hidden(png_structp png_ptr, png_infop info_ptr,
-+                              png_byte is_hidden)
-+{
-+    png_debug(1, "in png_first_frame_is_hidden()");
-+
-+    if (png_ptr == NULL)
-+        return 0;
-+
-+    if (is_hidden)
-+        png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
-+    else
-+        png_ptr->apng_flags &= ~PNG_FIRST_FRAME_HIDDEN;
-+
-+    PNG_UNUSED(info_ptr)
-+
-+    return 1;
-+}
-+#endif /* PNG_APNG_SUPPORTED */
-+
- #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
- static png_byte
- check_location(png_const_structrp png_ptr, int location)
-diff -Naru libpng-1.6.19.org/pngstruct.h libpng-1.6.19/pngstruct.h
---- libpng-1.6.19.org/pngstruct.h	2015-11-15 22:34:42.412615653 +0900
-+++ libpng-1.6.19/pngstruct.h	2015-11-15 22:34:42.480618027 +0900
-@@ -400,6 +400,27 @@
-    png_byte filter_type;
- #endif
- 
-+#ifdef PNG_APNG_SUPPORTED
-+   png_uint_32 apng_flags;
-+   png_uint_32 next_seq_num;         /* next fcTL/fdAT chunk sequence number */
-+   png_uint_32 first_frame_width;
-+   png_uint_32 first_frame_height;
-+
-+#ifdef PNG_READ_APNG_SUPPORTED
-+   png_uint_32 num_frames_read;      /* incremented after all image data of */
-+                                     /* a frame is read */
-+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-+   png_progressive_frame_ptr frame_info_fn; /* frame info read callback */
-+   png_progressive_frame_ptr frame_end_fn;  /* frame data read callback */
-+#endif
-+#endif
-+
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+   png_uint_32 num_frames_to_write;
-+   png_uint_32 num_frames_written;
-+#endif
-+#endif /* PNG_APNG_SUPPORTED */
-+
- /* New members added in libpng-1.2.0 */
- 
- /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
-diff -Naru libpng-1.6.19.org/pngwrite.c libpng-1.6.19/pngwrite.c
---- libpng-1.6.19.org/pngwrite.c	2015-11-15 22:34:42.413615688 +0900
-+++ libpng-1.6.19/pngwrite.c	2015-11-15 22:34:42.481618062 +0900
-@@ -128,6 +128,10 @@
-        * the application continues writing the PNG.  So check the 'invalid'
-        * flag here too.
-        */
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+      if (info_ptr->valid & PNG_INFO_acTL)
-+         png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
-+#endif
- #ifdef PNG_GAMMA_SUPPORTED
- #  ifdef PNG_WRITE_gAMA_SUPPORTED
-       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-@@ -365,6 +369,11 @@
-       png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
- #endif
- 
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+   if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
-+      png_error(png_ptr, "Not enough frames written");
-+#endif
-+
-    /* See if user wants us to write information chunks */
-    if (info_ptr != NULL)
-    {
-@@ -1450,6 +1459,43 @@
- }
- #endif
- 
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+void PNGAPI
-+png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
-+    png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
-+    png_byte blend_op)
-+{
-+    png_debug(1, "in png_write_frame_head");
-+
-+    /* there is a chance this has been set after png_write_info was called,
-+    * so it would be set but not written. is there a way to be sure? */
-+    if (!(info_ptr->valid & PNG_INFO_acTL))
-+        png_error(png_ptr, "png_write_frame_head(): acTL not set");
-+
-+    png_write_reset(png_ptr);
-+
-+    png_write_reinit(png_ptr, info_ptr, width, height);
-+
-+    if ( !(png_ptr->num_frames_written == 0 &&
-+           (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) ) )
-+        png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
-+                       delay_num, delay_den, dispose_op, blend_op);
-+
-+    PNG_UNUSED(row_pointers)
-+}
-+
-+void PNGAPI
-+png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
-+{
-+    png_debug(1, "in png_write_frame_tail");
-+
-+    png_ptr->num_frames_written++;
-+
-+    PNG_UNUSED(info_ptr)
-+}
-+#endif /* PNG_WRITE_APNG_SUPPORTED */
- 
- #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
- # ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
-diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
---- libpng-1.6.19.org/pngwutil.c	2015-11-15 22:34:42.414615723 +0900
-+++ libpng-1.6.19/pngwutil.c	2015-11-15 22:34:42.482618096 +0900
-@@ -901,6 +901,11 @@
+Index: pngwutil.c
+===================================================================
+--- pngwutil.c
++++ pngwutil.c
+@@ -817,6 +817,11 @@
     /* Write the chunk */
     png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
  
@@ -1390,38 +1444,39 @@ diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
     if ((png_ptr->do_filter) == PNG_NO_FILTERS)
     {
        if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
-@@ -1082,7 +1087,14 @@
+@@ -998,7 +1003,15 @@
                 optimize_cmf(data, png_image_size(png_ptr));
  #endif
  
-+#        ifdef PNG_WRITE_APNG_SUPPORTED
-+            if (png_ptr->num_frames_written == 0)
-+#        endif
++#ifdef PNG_WRITE_APNG_SUPPORTED
++         if (png_ptr->num_frames_written == 0)
++#endif
           png_write_complete_chunk(png_ptr, png_IDAT, data, size);
-+#        ifdef PNG_WRITE_APNG_SUPPORTED
-+            else
-+               png_write_fdAT(png_ptr, data, size);
-+#        endif /* PNG_WRITE_APNG_SUPPORTED */
++#ifdef PNG_WRITE_APNG_SUPPORTED
++         else
++            png_write_fdAT(png_ptr, data, size);
++#endif /* WRITE_APNG */
++
           png_ptr->mode |= PNG_HAVE_IDAT;
  
           png_ptr->zstream.next_out = data;
-@@ -1128,7 +1140,15 @@
+@@ -1044,7 +1057,15 @@
              optimize_cmf(data, png_image_size(png_ptr));
  #endif
  
-+#        ifdef PNG_WRITE_APNG_SUPPORTED
-+            if (png_ptr->num_frames_written == 0)
-+#        endif
++#ifdef PNG_WRITE_APNG_SUPPORTED
++         if (png_ptr->num_frames_written == 0)
++#endif
           png_write_complete_chunk(png_ptr, png_IDAT, data, size);
-+#        ifdef PNG_WRITE_APNG_SUPPORTED
-+            else
-+               png_write_fdAT(png_ptr, data, size);
-+#        endif /* PNG_WRITE_APNG_SUPPORTED */
++#ifdef PNG_WRITE_APNG_SUPPORTED
++         else
++            png_write_fdAT(png_ptr, data, size);
++#endif /* WRITE_APNG */
 +
           png_ptr->zstream.avail_out = 0;
           png_ptr->zstream.next_out = NULL;
           png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
-@@ -1941,6 +1961,82 @@
+@@ -1857,6 +1878,82 @@
  }
  #endif
  
@@ -1436,7 +1491,7 @@ diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
 +
 +    png_ptr->num_frames_to_write = num_frames;
 +
-+    if (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN)
++    if ((png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) != 0)
 +        num_frames--;
 +
 +    png_save_uint_32(buf, num_frames);
@@ -1499,12 +1554,12 @@ diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
 +
 +    png_ptr->next_seq_num++;
 +}
-+#endif /* PNG_WRITE_APNG_SUPPORTED */
++#endif /* WRITE_APNG */
 +
  /* Initializes the row writing capability of libpng */
  void /* PRIVATE */
  png_write_start_row(png_structrp png_ptr)
-@@ -2706,4 +2802,39 @@
+@@ -2622,4 +2719,39 @@
     }
  #endif /* WRITE_FLUSH */
  }
@@ -1529,7 +1584,7 @@ diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
 +                           "don't match the ones in IHDR");
 +    if (width > png_ptr->first_frame_width ||
 +        height > png_ptr->first_frame_height)
-+        png_error(png_ptr, "width and/or height for a frame greater than"
++        png_error(png_ptr, "width and/or height for a frame greater than "
 +                           "the ones in IHDR");
 +
 +    png_set_IHDR(png_ptr, info_ptr, width, height,
@@ -1542,32 +1597,33 @@ diff -Naru libpng-1.6.19.org/pngwutil.c libpng-1.6.19/pngwutil.c
 +    png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
 +    png_ptr->usr_width = png_ptr->width;
 +}
-+#endif /* PNG_WRITE_APNG_SUPPORTED */
++#endif /* WRITE_APNG */
  #endif /* WRITE */
-diff -Naru libpng-1.6.19.org/scripts/symbols.def libpng-1.6.19/scripts/symbols.def
---- libpng-1.6.19.org/scripts/symbols.def	2015-11-15 22:34:42.419615897 +0900
-+++ libpng-1.6.19/scripts/symbols.def	2015-11-15 22:34:42.486618236 +0900
-@@ -249,3 +249,23 @@
-  png_set_check_for_invalid_index @242
+Index: scripts/symbols.def
+===================================================================
+--- scripts/symbols.def
++++ scripts/symbols.def
+@@ -250,3 +250,23 @@
   png_get_palette_max @243
   png_set_option @244
-+ png_get_acTL @245
-+ png_set_acTL @246
-+ png_get_num_frames @247
-+ png_get_num_plays @248
-+ png_get_next_frame_fcTL @249
-+ png_set_next_frame_fcTL @250
-+ png_get_next_frame_width @251
-+ png_get_next_frame_height @252
-+ png_get_next_frame_x_offset @253
-+ png_get_next_frame_y_offset @254
-+ png_get_next_frame_delay_num @255
-+ png_get_next_frame_delay_den @256
-+ png_get_next_frame_dispose_op @257
-+ png_get_next_frame_blend_op @258
-+ png_get_first_frame_is_hidden @259
-+ png_set_first_frame_is_hidden @260
-+ png_read_frame_head @261
-+ png_set_progressive_frame_fn @262
-+ png_write_frame_head @263
-+ png_write_frame_tail @264
+  png_image_write_to_memory @245
++ png_get_acTL @246
++ png_set_acTL @247
++ png_get_num_frames @248
++ png_get_num_plays @249
++ png_get_next_frame_fcTL @250
++ png_set_next_frame_fcTL @251
++ png_get_next_frame_width @252
++ png_get_next_frame_height @253
++ png_get_next_frame_x_offset @254
++ png_get_next_frame_y_offset @255
++ png_get_next_frame_delay_num @256
++ png_get_next_frame_delay_den @257
++ png_get_next_frame_dispose_op @258
++ png_get_next_frame_blend_op @259
++ png_get_first_frame_is_hidden @260
++ png_set_first_frame_is_hidden @261
++ png_read_frame_head @262
++ png_set_progressive_frame_fn @263
++ png_write_frame_head @264
++ png_write_frame_tail @265