[LodePNG] Update lodepng to version 20150418.

components/external/lodepng/lodepng.h

@@ -1,7 +1,7 @@
 /*
-LodePNG version 20131222
+LodePNG version 20150418
 
-Copyright (c) 2005-2013 Lode Vandevenne
+Copyright (c) 2005-2015 Lode Vandevenne
 
 This software is provided 'as-is', without any express or implied
 warranty. In no event will the authors be held liable for any damages
@@ -36,6 +36,8 @@ freely, subject to the following restrictions:
 #include <string>
 #endif /*__cplusplus*/
 
+extern const char* LODEPNG_VERSION_STRING;
+
 /*
 The following #defines are used to create code sections. They can be disabled
 to disable code sections, which can give faster compile time and smaller binary.
@@ -198,7 +200,8 @@ unsigned lodepng_encode24_file(const char* filename,
 namespace lodepng
 {
 #ifdef LODEPNG_COMPILE_DECODER
-/*Same as lodepng_decode_memory, but decodes to an std::vector.*/
+/*Same as lodepng_decode_memory, but decodes to an std::vector. The colortype
+is the format to output the pixels to. Default is RGBA 8-bit per channel.*/
 unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
                 const unsigned char* in, size_t insize,
                 LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
@@ -213,11 +216,12 @@ Same as the other decode functions, but instead takes a filename as input.
 unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
                 const std::string& filename,
                 LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#endif //LODEPNG_COMPILE_DISK
-#endif //LODEPNG_COMPILE_DECODER
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_DECODER */
 
 #ifdef LODEPNG_COMPILE_ENCODER
-/*Same as lodepng_encode_memory, but encodes to an std::vector.*/
+/*Same as lodepng_encode_memory, but encodes to an std::vector. colortype
+is that of the raw input data. The output PNG color type will be auto chosen.*/
 unsigned encode(std::vector<unsigned char>& out,
                 const unsigned char* in, unsigned w, unsigned h,
                 LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
@@ -236,9 +240,9 @@ unsigned encode(const std::string& filename,
 unsigned encode(const std::string& filename,
                 const std::vector<unsigned char>& in, unsigned w, unsigned h,
                 LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#endif //LODEPNG_COMPILE_DISK
-#endif //LODEPNG_COMPILE_ENCODER
-} //namespace lodepng
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_ENCODER */
+} /* namespace lodepng */
 #endif /*LODEPNG_COMPILE_CPP*/
 #endif /*LODEPNG_COMPILE_PNG*/
 
@@ -283,7 +287,7 @@ struct LodePNGCompressSettings /*deflate = compress*/
   /*LZ77 related settings*/
   unsigned btype; /*the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.*/
   unsigned use_lz77; /*whether or not to use LZ77. Should be 1 for proper compression.*/
-  unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Typical value: 2048.*/
+  unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Default value: 2048.*/
   unsigned minmatch; /*mininum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0*/
   unsigned nicematch; /*stop searching if >= this length found. Set to 258 for best compression. Default: 128*/
   unsigned lazymatching; /*use lazy matching: better compression but a bit slower. Default: true*/
@@ -499,13 +503,14 @@ LodePNGColorMode structs to describe the input and output color type.
 See the reference manual at the end of this header file to see which color conversions are supported.
 return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported)
 The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel
-of the output color type (lodepng_get_bpp)
-The fix_png value works as described in struct LodePNGDecoderSettings.
-Note: for 16-bit per channel colors, uses big endian format like PNG does.
+of the output color type (lodepng_get_bpp).
+For < 8 bpp images, there should not be padding bits at the end of scanlines.
+For 16-bit per channel colors, uses big endian format like PNG does.
+Return value is LodePNG error code
 */
 unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
                          LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
-                         unsigned w, unsigned h, unsigned fix_png);
+                         unsigned w, unsigned h);
 
 #ifdef LODEPNG_COMPILE_DECODER
 /*
@@ -517,16 +522,7 @@ typedef struct LodePNGDecoderSettings
   LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/
 
   unsigned ignore_crc; /*ignore CRC checksums*/
-  /*
-  The fix_png setting, if 1, makes the decoder tolerant towards some PNG images
-  that do not correctly follow the PNG specification. This only supports errors
-  that are fixable, were found in images that are actually used on the web, and
-  are silently tolerated by other decoders as well. Currently only one such fix
-  is implemented: if a palette index is out of bounds given the palette size,
-  interpret it as opaque black.
-  By default this value is 0, which makes it stop with an error on such images.
-  */
-  unsigned fix_png;
+
   unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/
 
 #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
@@ -559,46 +555,39 @@ typedef enum LodePNGFilterStrategy
   LFS_PREDEFINED
 } LodePNGFilterStrategy;
 
-/*automatically use color type with less bits per pixel if losslessly possible. Default: LAC_AUTO*/
-typedef enum LodePNGAutoConvert
+/*Gives characteristics about the colors of the image, which helps decide which color model to use for encoding.
+Used internally by default if "auto_convert" is enabled. Public because it's useful for custom algorithms.*/
+typedef struct LodePNGColorProfile
 {
-  LAC_NO, /*use color type user requested*/
-  LAC_ALPHA, /*use color type user requested, but if only opaque pixels and RGBA or grey+alpha, use RGB or grey*/
-  LAC_AUTO, /*use PNG color type that can losslessly represent the uncompressed image the smallest possible*/
-  /*
-  like AUTO, but do not choose 1, 2 or 4 bit per pixel types.
-  sometimes a PNG image compresses worse if less than 8 bits per pixels.
-  */
-  LAC_AUTO_NO_NIBBLES,
-  /*
-  like AUTO, but never choose palette color type. For small images, encoding
-  the palette may take more bytes than what is gained. Note that AUTO also
-  already prevents encoding the palette for extremely small images, but that may
-  not be sufficient because due to the compression it cannot predict when to
-  switch.
-  */
-  LAC_AUTO_NO_PALETTE,
-  LAC_AUTO_NO_NIBBLES_NO_PALETTE
-} LodePNGAutoConvert;
-
-
-/*
-Automatically chooses color type that gives smallest amount of bits in the
-output image, e.g. grey if there are only greyscale pixels, palette if there
-are less than 256 colors, ...
-The auto_convert parameter allows limiting it to not use palette, ...
-*/
+  unsigned colored; /*not greyscale*/
+  unsigned key; /*if true, image is not opaque. Only if true and alpha is false, color key is possible.*/
+  unsigned short key_r; /*these values are always in 16-bit bitdepth in the profile*/
+  unsigned short key_g;
+  unsigned short key_b;
+  unsigned alpha; /*alpha channel or alpha palette required*/
+  unsigned numcolors; /*amount of colors, up to 257. Not valid if bits == 16.*/
+  unsigned char palette[1024]; /*Remembers up to the first 256 RGBA colors, in no particular order*/
+  unsigned bits; /*bits per channel (not for palette). 1,2 or 4 for greyscale only. 16 if 16-bit per channel required.*/
+} LodePNGColorProfile;
+
+void lodepng_color_profile_init(LodePNGColorProfile* profile);
+
+/*Get a LodePNGColorProfile of the image.*/
+unsigned lodepng_get_color_profile(LodePNGColorProfile* profile,
+                                   const unsigned char* image, unsigned w, unsigned h,
+                                   const LodePNGColorMode* mode_in);
+/*The function LodePNG uses internally to decide the PNG color with auto_convert.
+Chooses an optimal color model, e.g. grey if only grey pixels, palette if < 256 colors, ...*/
 unsigned lodepng_auto_choose_color(LodePNGColorMode* mode_out,
                                    const unsigned char* image, unsigned w, unsigned h,
-                                   const LodePNGColorMode* mode_in,
-                                   LodePNGAutoConvert auto_convert);
+                                   const LodePNGColorMode* mode_in);
 
 /*Settings for the encoder.*/
 typedef struct LodePNGEncoderSettings
 {
   LodePNGCompressSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/
 
-  LodePNGAutoConvert auto_convert; /*how to automatically choose output PNG color type, if at all*/
+  unsigned auto_convert; /*automatically choose output PNG color type. Default: true*/
 
   /*If true, follows the official PNG heuristic: if the PNG uses a palette or lower than
   8 bit depth, set all filters to zero. Otherwise use the filter_strategy. Note that to
@@ -643,7 +632,7 @@ typedef struct LodePNGState
   LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/
   unsigned error;
 #ifdef LODEPNG_COMPILE_CPP
-  //For the lodepng::State subclass.
+  /* For the lodepng::State subclass. */
   virtual ~LodePNGState(){}
 #endif
 } LodePNGState;
@@ -693,7 +682,11 @@ Third byte: must be uppercase
 Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy
 */
 
-/*get the length of the data of the chunk. Total chunk length has 12 bytes more.*/
+/*
+Gets the length of the data of the chunk. Total chunk length has 12 bytes more.
+There must be at least 4 bytes to read from. If the result value is too large,
+it may be corrupt data.
+*/
 unsigned lodepng_chunk_length(const unsigned char* chunk);
 
 /*puts the 4-byte type in null terminated string*/
@@ -821,7 +814,7 @@ unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const
 #endif /*LODEPNG_COMPILE_DISK*/
 
 #ifdef LODEPNG_COMPILE_CPP
-//The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers.
+/* The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers. */
 namespace lodepng
 {
 #ifdef LODEPNG_COMPILE_PNG
@@ -835,7 +828,7 @@ class State : public LodePNGState
 };
 
 #ifdef LODEPNG_COMPILE_DECODER
-//Same as other lodepng::decode, but using a State for more settings and information.
+/* Same as other lodepng::decode, but using a State for more settings and information. */
 unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
                 State& state,
                 const unsigned char* in, size_t insize);
@@ -845,7 +838,7 @@ unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
 #endif /*LODEPNG_COMPILE_DECODER*/
 
 #ifdef LODEPNG_COMPILE_ENCODER
-//Same as other lodepng::encode, but using a State for more settings and information.
+/* Same as other lodepng::encode, but using a State for more settings and information. */
 unsigned encode(std::vector<unsigned char>& out,
                 const unsigned char* in, unsigned w, unsigned h,
                 State& state);
@@ -866,31 +859,31 @@ Save the binary data in an std::vector to a file on disk. The file is overwritte
 without warning.
 */
 void save_file(const std::vector<unsigned char>& buffer, const std::string& filename);
-#endif //LODEPNG_COMPILE_DISK
-#endif //LODEPNG_COMPILE_PNG
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_PNG */
 
 #ifdef LODEPNG_COMPILE_ZLIB
 #ifdef LODEPNG_COMPILE_DECODER
-//Zlib-decompress an unsigned char buffer
+/* Zlib-decompress an unsigned char buffer */
 unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
                     const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
 
-//Zlib-decompress an std::vector
+/* Zlib-decompress an std::vector */
 unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
                     const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
-#endif //LODEPNG_COMPILE_DECODER
+#endif /* LODEPNG_COMPILE_DECODER */
 
 #ifdef LODEPNG_COMPILE_ENCODER
-//Zlib-compress an unsigned char buffer
+/* Zlib-compress an unsigned char buffer */
 unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
                   const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
 
-//Zlib-compress an std::vector
+/* Zlib-compress an std::vector */
 unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
                   const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
-#endif //LODEPNG_COMPILE_ENCODER
-#endif //LODEPNG_COMPILE_ZLIB
-} //namespace lodepng
+#endif /* LODEPNG_COMPILE_ENCODER */
+#endif /* LODEPNG_COMPILE_ZLIB */
+} /* namespace lodepng */
 #endif /*LODEPNG_COMPILE_CPP*/
 
 /*
@@ -904,8 +897,8 @@ TODO:
 [X] let the "isFullyOpaque" function check color keys and transparent palettes too
 [X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl"
 [ ] don't stop decoding on errors like 69, 57, 58 (make warnings)
-[ ] make option to choose if the raw image with non multiple of 8 bits per scanline should have padding bits or not
 [ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes
+[ ] allow user to provide custom color conversion functions, e.g. for premultiplied alpha, padding bits or not, ...
 */
 
 #endif /*LODEPNG_H inclusion guard*/
@@ -1243,20 +1236,22 @@ behaviour.
 
 If, when decoding, you want the raw image to be something else than the default,
 you need to set the color type and bit depth you want in the LodePNGColorMode,
-or the parameters of the simple function of LodePNG you're using.
+or the parameters colortype and bitdepth of the simple decoding function.
 
-If, when encoding, you use another color type than the default in the input
+If, when encoding, you use another color type than the default in the raw input
 image, you need to specify its color type and bit depth in the LodePNGColorMode
-of the raw image, or use the parameters of the simplefunction of LodePNG you're
-using.
+of the raw image, or use the parameters colortype and bitdepth of the simple
+encoding function.
 
 If, when encoding, you don't want LodePNG to choose the output PNG color type
 but control it yourself, you need to set auto_convert in the encoder settings
-to LAC_NONE, and specify the color type you want in the LodePNGInfo of the
-encoder.
+to false, and specify the color type you want in the LodePNGInfo of the
+encoder (including palette: it can generate a palette if auto_convert is true,
+otherwise not).
 
-If you do any of the above, LodePNG may need to do a color conversion, which
-follows the rules below, and may sometimes not be allowed.
+If the input and output color type differ (whether user chosen or auto chosen),
+LodePNG will do a color conversion, which follows the rules below, and may
+sometimes result in an error.
 
 To avoid some confusion:
 -the decoder converts from PNG to raw image
@@ -1278,7 +1273,7 @@ To avoid some confusion:
 Non supported color conversions:
 -color to greyscale: no error is thrown, but the result will look ugly because
 only the red channel is taken
--anything, to palette when that palette does not have that color in it: in this
+-anything to palette when that palette does not have that color in it: in this
 case an error is thrown
 
 Supported color conversions:
@@ -1288,10 +1283,10 @@ Supported color conversions:
 -removing alpha channel
 -higher to smaller bitdepth, and vice versa
 
-If you want no color conversion to be done:
+If you want no color conversion to be done (e.g. for speed or control):
 -In the encoder, you can make it save a PNG with any color type by giving the
 raw color mode and LodePNGInfo the same color mode, and setting auto_convert to
-LAC_NO.
+false.
 -In the decoder, you can make it store the pixel data in the same color type
 as the PNG has, by setting the color_convert setting to false. Settings in
 info_raw are then ignored.
@@ -1458,6 +1453,8 @@ LodePNG. For the C++ version, only the standard C++ library is needed on top.
 Add the files lodepng.c(pp) and lodepng.h to your project, include
 lodepng.h where needed, and your program can read/write PNG files.
 
+It is compatible with C90 and up, and C++03 and up.
+
 If performance is important, use optimization when compiling! For both the
 encoder and decoder, this makes a large difference.
 
@@ -1473,49 +1470,40 @@ LodePNG is developed in gcc so this compiler is natively supported. It gives no
 warnings with compiler options "-Wall -Wextra -pedantic -ansi", with gcc and g++
 version 4.7.1 on Linux, 32-bit and 64-bit.
 
-*) Mingw
+*) Clang
 
-The Mingw compiler (a port of gcc) for Windows is fully supported by LodePNG.
+Fully supported and warning-free.
 
-*) Visual Studio 2005 and up, Visual C++ Express Edition 2005 and up
+*) Mingw
+
+The Mingw compiler (a port of gcc for Windows) should be fully supported by
+LodePNG.
 
-Visual Studio may give warnings about 'fopen' being deprecated. A multiplatform library
-can't support the proposed Visual Studio alternative however, so LodePNG keeps using
-fopen. If you don't want to see the deprecated warnings, put this on top of lodepng.h
-before the inclusions:
-#define _CRT_SECURE_NO_DEPRECATE
+*) Visual Studio and Visual C++ Express Edition
 
-Other than the above warnings, LodePNG should be warning-free with warning
-level 3 (W3). Warning level 4 (W4) will give warnings about integer conversions.
-I'm not planning to resolve these warnings. To get rid of them, let Visual
-Studio use warning level W3 for lodepng.cpp only: right click lodepng.cpp,
-Properties, C/C++, General, Warning Level: Level 3 (/W3).
+LodePNG should be warning-free with warning level W4. Two warnings were disabled
+with pragmas though: warning 4244 about implicit conversions, and warning 4996
+where it wants to use a non-standard function fopen_s instead of the standard C
+fopen.
 
 Visual Studio may want "stdafx.h" files to be included in each source file and
 give an error "unexpected end of file while looking for precompiled header".
-That is not standard C++ and will not be added to the stock LodePNG. You can
+This is not standard C++ and will not be added to the stock LodePNG. You can
 disable it for lodepng.cpp only by right clicking it, Properties, C/C++,
 Precompiled Headers, and set it to Not Using Precompiled Headers there.
 
-*) Visual Studio 6.0
-
-LodePNG support for Visual Studio 6.0 is not guaranteed because VS6 doesn't
-follow the C++ standard correctly.
-
-*) Comeau C/C++
-
-Vesion 20070107 compiles without problems on the Comeau C/C++ Online Test Drive
-at http://www.comeaucomputing.com/tryitout in both C90 and C++ mode.
+NOTE: Modern versions of VS should be fully supported, but old versions, e.g.
+VS6, are not guaranteed to work.
 
 *) Compilers on Macintosh
 
-LodePNG has been reported to work both with the gcc and LLVM for Macintosh, both
-for C and C++.
+LodePNG has been reported to work both with gcc and LLVM for Macintosh, both for
+C and C++.
 
 *) Other Compilers
 
-If you encounter problems on other compilers, feel free to let me know and I may
-try to fix it if the compiler is modern standards complient.
+If you encounter problems on any compilers, feel free to let me know and I may
+try to fix it if the compiler is modern and standards complient.
 
 
 10. examples
@@ -1577,6 +1565,11 @@ yyyymmdd.
 Some changes aren't backwards compatible. Those are indicated with a (!)
 symbol.
 
+*) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding.
+*) 23 aug 2014: Reduced needless memory usage of decoder.
+*) 28 jun 2014: Removed fix_png setting, always support palette OOB for
+    simplicity. Made ColorProfile public.
+*) 09 jun 2014: Faster encoder by fixing hash bug and more zeros optimization.
 *) 22 dec 2013: Power of two windowsize required for optimization.
 *) 15 apr 2013: Fixed bug with LAC_ALPHA and color key.
 *) 25 mar 2013: Added an optional feature to ignore some PNG errors (fix_png).
@@ -1715,5 +1708,5 @@ Domain: gmail dot com.
 Account: lode dot vandevenne.
 
 
-Copyright (c) 2005-2013 Lode Vandevenne
+Copyright (c) 2005-2015 Lode Vandevenne
 */