/*

LodePNG version 20080927

Copyright (c) 2005-2008 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

arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,

including commercial applications, and to alter it and redistribute it

freely, subject to the following restrictions:

    1. The origin of this software must not be misrepresented; you must not

    claim that you wrote the original software. If you use this software

    in a product, an acknowledgment in the product documentation would be

    appreciated but is not required.

    2. Altered source versions must be plainly marked as such, and must not be

    misrepresented as being the original software.

    3. This notice may not be removed or altered from any source

    distribution.

*/

#ifndef LODEPNG_H

#define LODEPNG_H

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

/* ////////////////////////////////////////////////////////////////////////// */

/* Code Sections                                                              */

/* ////////////////////////////////////////////////////////////////////////// */

/*The following defines can be commented disable code sections. Gives potential faster compile and smaller binary.*/

#define LODEPNG_COMPILE_ZLIB             /*deflate&zlib encoder and deflate&zlib decoder*/

#define LODEPNG_COMPILE_PNG              /*png encoder and png decoder*/

//#define LODEPNG_COMPILE_DECODER          /*deflate&zlib decoder and png decoder*/

#define LODEPNG_COMPILE_ENCODER          /*deflate&zlib encoder and png encoder*/

#define LODEPNG_COMPILE_DISK             /*the optional built in harddisk file loading and saving functions*/

//#define LODEPNG_COMPILE_ANCILLARY_CHUNKS /*any code or struct datamember related to chunks other than IHDR, IDAT, PLTE, tRNS, IEND*/

//#define LODEPNG_COMPILE_UNKNOWN_CHUNKS   /*handling of unknown chunks*/

/* ////////////////////////////////////////////////////////////////////////// */

/* LodeFlate & LodeZlib Setting structs                                       */

/* ////////////////////////////////////////////////////////////////////////// */

#ifdef LODEPNG_COMPILE_DECODER

typedef struct LodeZlib_DecompressSettings

{

  unsigned ignoreAdler32;

} LodeZlib_DecompressSettings;

extern const LodeZlib_DecompressSettings LodeZlib_defaultDecompressSettings;

void LodeZlib_DecompressSettings_init(LodeZlib_DecompressSettings* settings);

#endif /*LODEPNG_COMPILE_DECODER*/

#ifdef LODEPNG_COMPILE_ENCODER

typedef struct LodeZlib_DeflateSettings /*deflate = compress*/

{

  /*LZ77 related settings*/

  unsigned btype; /*the block type for LZ*/

  unsigned useLZ77; /*whether or not to use LZ77*/

  unsigned windowSize; /*the maximum is 32768*/

} LodeZlib_DeflateSettings;

extern const LodeZlib_DeflateSettings LodeZlib_defaultDeflateSettings;

void LodeZlib_DeflateSettings_init(LodeZlib_DeflateSettings* settings);

#endif /*LODEPNG_COMPILE_ENCODER*/

#ifdef LODEPNG_COMPILE_ZLIB

/* ////////////////////////////////////////////////////////////////////////// */

/* LodeFlate & LodeZlib                                                       */

/* ////////////////////////////////////////////////////////////////////////// */

#ifdef LODEPNG_COMPILE_DECODER

/*This function reallocates the out buffer and appends the data.

Either, *out must be NULL and *outsize must be 0, or, *out must be a valid buffer and *outsize its size in bytes.*/

unsigned LodeZlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DecompressSettings* settings);

#endif /*LODEPNG_COMPILE_DECODER*/

#ifdef LODEPNG_COMPILE_ENCODER

/*This function reallocates the out buffer and appends the data.

Either, *out must be NULL and *outsize must be 0, or, *out must be a valid buffer and *outsize its size in bytes.*/

unsigned LodeZlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DeflateSettings* settings);

#endif /*LODEPNG_COMPILE_ENCODER*/

#endif /*LODEPNG_COMPILE_ZLIB*/

#ifdef LODEPNG_COMPILE_PNG

/* ////////////////////////////////////////////////////////////////////////// */

/* LodePNG                                                                    */

/* ////////////////////////////////////////////////////////////////////////// */

/*LodePNG_chunk functions: These functions need as input a large enough amount of allocated memory.*/

unsigned LodePNG_chunk_length(const unsigned char* chunk); /*get the length of the data of the chunk. Total chunk length has 12 bytes more.*/

void LodePNG_chunk_type(char type[5], const unsigned char* chunk); /*puts the 4-byte type in null terminated string*/

unsigned char LodePNG_chunk_type_equals(const unsigned char* chunk, const char* type); /*check if the type is the given type*/

/*properties of PNG chunks gotten from capitalization of chunk type name, as defined by the standard*/

unsigned char LodePNG_chunk_critical(const unsigned char* chunk); /*0: ancillary chunk, 1: it's one of the critical chunk types*/

unsigned char LodePNG_chunk_private(const unsigned char* chunk); /*0: public, 1: private*/

unsigned char LodePNG_chunk_safetocopy(const unsigned char* chunk); /*0: the chunk is unsafe to copy, 1: the chunk is safe to copy*/

unsigned char* LodePNG_chunk_data(unsigned char* chunk); /*get pointer to the data of the chunk*/

const unsigned char* LodePNG_chunk_data_const(const unsigned char* chunk); /*get pointer to the data of the chunk*/

unsigned LodePNG_chunk_check_crc(const unsigned char* chunk); /*returns 0 if the crc is correct, 1 if it's incorrect*/

void LodePNG_chunk_generate_crc(unsigned char* chunk); /*generates the correct CRC from the data and puts it in the last 4 bytes of the chunk*/

/*iterate to next chunks.*/

unsigned char* LodePNG_chunk_next(unsigned char* chunk);

const unsigned char* LodePNG_chunk_next_const(const unsigned char* chunk);

/*add chunks to out buffer. It reallocs the buffer to append the data. returns error code*/

unsigned LodePNG_append_chunk(unsigned char** out, size_t* outlength, const unsigned char* chunk); /*appends chunk that was already created, to the data. Returns pointer to start of appended chunk, or NULL if error happened*/

unsigned LodePNG_create_chunk(unsigned char** out, size_t* outlength, unsigned length, const char* type, const unsigned char* data); /*appends new chunk to out. Returns pointer to start of appended chunk, or NULL if error happened; may change memory address of out buffer*/

typedef struct LodePNG_InfoColor /*info about the color type of an image*/

{

  /*header (IHDR)*/

  unsigned colorType; /*color type*/

  unsigned bitDepth;  /*bits per sample*/

  /*palette (PLTE)*/

  unsigned char* palette; /*palette in RGBARGBA... order*/

  size_t palettesize; /*palette size in number of colors (amount of bytes is 4 * palettesize)*/

  /*transparent color key (tRNS)*/

  unsigned key_defined; /*is a transparent color key given?*/

  unsigned key_r;       /*red component of color key*/

  unsigned key_g;       /*green component of color key*/

  unsigned key_b;       /*blue component of color key*/

} LodePNG_InfoColor;

void LodePNG_InfoColor_init(LodePNG_InfoColor* info);

void LodePNG_InfoColor_cleanup(LodePNG_InfoColor* info);

unsigned LodePNG_InfoColor_copy(LodePNG_InfoColor* dest, const LodePNG_InfoColor* source);

/*Use these functions instead of allocating palette manually*/

void LodePNG_InfoColor_clearPalette(LodePNG_InfoColor* info);

unsigned LodePNG_InfoColor_addPalette(LodePNG_InfoColor* info, unsigned char r, unsigned char g, unsigned char b, unsigned char a); /*add 1 color to the palette*/

/*additional color info*/

unsigned LodePNG_InfoColor_getBpp(const LodePNG_InfoColor* info);      /*bits per pixel*/

unsigned LodePNG_InfoColor_getChannels(const LodePNG_InfoColor* info); /*amount of channels*/

unsigned LodePNG_InfoColor_isGreyscaleType(const LodePNG_InfoColor* info); /*is it a greyscale type? (colorType 0 or 4)*/

unsigned LodePNG_InfoColor_isAlphaType(const LodePNG_InfoColor* info);     /*has it an alpha channel? (colorType 2 or 6)*/

#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS

typedef struct LodePNG_Time /*LodePNG's encoder does not generate the current time. To make it add a time chunk the correct time has to be provided*/

{

  unsigned      year;    /*2 bytes*/

  unsigned char month;   /*1-12*/

  unsigned char day;     /*1-31*/

  unsigned char hour;    /*0-23*/

  unsigned char minute;  /*0-59*/

  unsigned char second;  /*0-60 (to allow for leap seconds)*/

} LodePNG_Time;

typedef struct LodePNG_Text /*non-international text*/

{

  size_t num;

  char** keys; /*the keyword of a text chunk (e.g. "Comment")*/

  char** strings; /*the actual text*/

} LodePNG_Text;

void LodePNG_Text_init(LodePNG_Text* text);

void LodePNG_Text_cleanup(LodePNG_Text* text);

unsigned LodePNG_Text_copy(LodePNG_Text* dest, const LodePNG_Text* source);

/*Use these functions instead of allocating the char**s manually*/

void LodePNG_Text_clear(LodePNG_Text* text);

unsigned LodePNG_Text_add(LodePNG_Text* text, const char* key, const char* str); /*push back both texts at once*/

typedef struct LodePNG_IText /*international text*/

{

  size_t num;

  char** keys; /*the English keyword of the text chunk (e.g. "Comment")*/

  char** langtags; /*the language tag for this text's international language, ISO/IEC 646 string, e.g. ISO 639 language tag*/

  char** transkeys; /*keyword translated to the international language - UTF-8 string*/

  char** strings; /*the actual international text - UTF-8 string*/

} LodePNG_IText;

void LodePNG_IText_init(LodePNG_IText* text);

void LodePNG_IText_cleanup(LodePNG_IText* text);

unsigned LodePNG_IText_copy(LodePNG_IText* dest, const LodePNG_IText* source);

/*Use these functions instead of allocating the char**s manually*/

void LodePNG_IText_clear(LodePNG_IText* text);

unsigned LodePNG_IText_add(LodePNG_IText* text, const char* key, const char* langtag, const char* transkey, const char* str); /*push back the 4 texts of 1 chunk at once*/

#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

#ifdef LODEPNG_COMPILE_UNKNOWN_CHUNKS

typedef struct LodePNG_UnknownChunks /*unknown chunks read from the PNG, or extra chunks the user wants to have added in the encoded PNG*/

{

  /*There are 3 buffers, one for each position in the PNG where unknown chunks can appear

    each buffer contains all unknown chunks for that position consecutively

    The 3 buffers are the unknown chunks between certain critical chunks:

    0: IHDR-PLTE, 1: PLTE-IDAT, 2: IDAT-IEND*/

  unsigned char* data[3];

  size_t datasize[3]; /*size in bytes of the unknown chunks, given for protection*/

} LodePNG_UnknownChunks;

void LodePNG_UnknownChunks_init(LodePNG_UnknownChunks* chunks);

void LodePNG_UnknownChunks_cleanup(LodePNG_UnknownChunks* chunks);

unsigned LodePNG_UnknownChunks_copy(LodePNG_UnknownChunks* dest, const LodePNG_UnknownChunks* src);

#endif /*LODEPNG_COMPILE_UNKNOWN_CHUNKS*/

typedef struct LodePNG_InfoPng /*information about the PNG image, except pixels and sometimes except width and height*/

{

  /*header (IHDR), palette (PLTE) and transparency (tRNS)*/

  unsigned width;             /*width of the image in pixels (ignored by encoder, but filled in by decoder)*/

  unsigned height;            /*height of the image in pixels (ignored by encoder, but filled in by decoder)*/

  unsigned compressionMethod; /*compression method of the original file*/

  unsigned filterMethod;      /*filter method of the original file*/

  unsigned interlaceMethod;   /*interlace method of the original file*/

  LodePNG_InfoColor color;    /*color type and bits, palette, transparency*/

#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS

  /*suggested background color (bKGD)*/

  unsigned background_defined; /*is a suggested background color given?*/

  unsigned background_r;       /*red component of suggested background color*/

  unsigned background_g;       /*green component of suggested background color*/

  unsigned background_b;       /*blue component of suggested background color*/

  /*non-international text chunks (tEXt and zTXt)*/

  LodePNG_Text text;

  /*international text chunks (iTXt)*/

  LodePNG_IText itext;

  /*time chunk (tIME)*/

  unsigned char time_defined; /*if 0, no tIME chunk was or will be generated in the PNG image*/

  LodePNG_Time time;

  /*phys chunk (pHYs)*/

  unsigned      phys_defined; /*is pHYs chunk defined?*/

  unsigned      phys_x;

  unsigned      phys_y;

  unsigned char phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/

#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

#ifdef LODEPNG_COMPILE_UNKNOWN_CHUNKS

  /*unknown chunks*/

  LodePNG_UnknownChunks unknown_chunks;

#endif /*LODEPNG_COMPILE_UNKNOWN_CHUNKS*/

} LodePNG_InfoPng;

void LodePNG_InfoPng_init(LodePNG_InfoPng* info);

void LodePNG_InfoPng_cleanup(LodePNG_InfoPng* info);

unsigned LodePNG_InfoPng_copy(LodePNG_InfoPng* dest, const LodePNG_InfoPng* source);

typedef struct LodePNG_InfoRaw /*contains user-chosen information about the raw image data, which is independent of the PNG image*/

{

  LodePNG_InfoColor color;

} LodePNG_InfoRaw;

void LodePNG_InfoRaw_init(LodePNG_InfoRaw* info);

void LodePNG_InfoRaw_cleanup(LodePNG_InfoRaw* info);

unsigned LodePNG_InfoRaw_copy(LodePNG_InfoRaw* dest, const LodePNG_InfoRaw* source);

/*

LodePNG_convert: Converts from any color type to 24-bit or 32-bit (later maybe more supported). return value = LodePNG error code

The out buffer must have (w * h * bpp + 7) / 8, where bpp is the bits per pixel of the output color type (LodePNG_InfoColor_getBpp)

*/

unsigned LodePNG_convert(unsigned char* out, const unsigned char* in, LodePNG_InfoColor* infoOut, LodePNG_InfoColor* infoIn, unsigned w, unsigned h);

#ifdef LODEPNG_COMPILE_DECODER

typedef struct LodePNG_DecodeSettings

{

  LodeZlib_DecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/

  unsigned ignoreCrc; /*ignore CRC checksums*/

  unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/

#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS

  unsigned readTextChunks; /*if false but rememberUnknownChunks is true, they're stored in the unknown chunks*/

#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

#ifdef LODEPNG_COMPILE_UNKNOWN_CHUNKS

  unsigned rememberUnknownChunks; /*store all bytes from unknown chunks in the InfoPng (off by default, useful for a png editor)*/

#endif /*LODEPNG_COMPILE_UNKNOWN_CHUNKS*/

} LodePNG_DecodeSettings;

void LodePNG_DecodeSettings_init(LodePNG_DecodeSettings* settings);

typedef struct LodePNG_Decoder

{

  LodePNG_DecodeSettings settings;

  LodePNG_InfoRaw infoRaw;

  LodePNG_InfoPng infoPng; /*info of the PNG image obtained after decoding*/

  unsigned error;

} LodePNG_Decoder;

void LodePNG_Decoder_init(LodePNG_Decoder* decoder);

void LodePNG_Decoder_cleanup(LodePNG_Decoder* decoder);

void LodePNG_Decoder_copy(LodePNG_Decoder* dest, const LodePNG_Decoder* source);

/*decoding functions*/

/*This function allocates the out buffer and stores the size in *outsize.*/

void LodePNG_decode(LodePNG_Decoder* decoder, unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize);

unsigned LodePNG_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize); /*return value is error*/

#ifdef LODEPNG_COMPILE_DISK

unsigned LodePNG_decode32f(unsigned char** out, unsigned* w, unsigned* h, const char* filename);

#endif /*LODEPNG_COMPILE_DISK*/

void LodePNG_inspect(LodePNG_Decoder* decoder, const unsigned char* in, size_t size); /*read the png header*/

#endif /*LODEPNG_COMPILE_DECODER*/

#ifdef LODEPNG_COMPILE_ENCODER

typedef struct LodePNG_EncodeSettings

{

  LodeZlib_DeflateSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/

  unsigned autoLeaveOutAlphaChannel; /*automatically use color type without alpha instead of given one, if given image is opaque*/

  unsigned force_palette; /*force creating a PLTE chunk if colortype is 2 or 6 (= a suggested palette). If colortype is 3, PLTE is _always_ created.*/

#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS

  unsigned add_id; /*add LodePNG version as text chunk*/

  unsigned text_compression; /*encode text chunks as zTXt chunks instead of tEXt chunks, and use compression in iTXt chunks*/

#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

} LodePNG_EncodeSettings;

void LodePNG_EncodeSettings_init(LodePNG_EncodeSettings* settings);

typedef struct LodePNG_Encoder

{

  LodePNG_EncodeSettings settings;

  LodePNG_InfoPng infoPng; /*the info specified by the user may not be changed by the encoder. The encoder will try to generate a PNG close to the given info.*/

  LodePNG_InfoRaw infoRaw; /*put the properties of the input raw image in here*/

  unsigned error;

} LodePNG_Encoder;

void LodePNG_Encoder_init(LodePNG_Encoder* encoder);

void LodePNG_Encoder_cleanup(LodePNG_Encoder* encoder);

void LodePNG_Encoder_copy(LodePNG_Encoder* dest, const LodePNG_Encoder* source);

/*This function allocates the out buffer and stores the size in *outsize.*/

void LodePNG_encode(LodePNG_Encoder* encoder, unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h);

unsigned LodePNG_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h); /*return value is error*/

#ifdef LODEPNG_COMPILE_DISK

unsigned LodePNG_encode32f(const char* filename, const unsigned char* image, unsigned w, unsigned h);

#endif /*LODEPNG_COMPILE_DISK*/

#endif /*LODEPNG_COMPILE_ENCODER*/

#endif /*LODEPNG_COMPILE_PNG*/

#ifdef LODEPNG_COMPILE_DISK

/*free functions allowing to load and save a file from/to harddisk*/

/*This function allocates the out buffer and stores the size in *outsize.*/

unsigned LodePNG_loadFile(unsigned char** out, size_t* outsize, const char* filename);

unsigned LodePNG_saveFile(const unsigned char* buffer, size_t buffersize, const char* filename);

#endif /*LODEPNG_COMPILE_DISK*/

/*

TODO:

[ ] test if there are no memory leaks or security exploits - done a lot but needs to be checked often

[ ] LZ77 encoder more like the one described in zlib - to make sure it's patentfree

[ ] converting color to 16-bit types

[ ] read all public PNG chunk types (but never let the color profile and gamma ones ever touch RGB values, that is very annoying for textures as well as images in a browser)

[ ] make sure encoder generates no chunks with size > (2^31)-1

[ ] partial decoding (stream processing)

[ ] let the "isFullyOpaque" function check color keys and transparent palettes too

[ ] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl"

[ ] check compatibility with vareous compilers  - done but needs to be redone for every newer version

[ ] don't stop decoding on errors like 69, 57, 58 (make warnings that the decoder stores in the error at the very end? and make some errors just let it stop with this one chunk but still do the next ones)

[ ] make option to choose if the raw image with non multiple of 8 bits per scanline should have padding bits or not, if people like storing raw images that way

*/

#endif

/*

LodePNG Documentation

---------------------

0. table of contents

--------------------

  1. about

   1.1. supported features

   1.2. features not supported

  2. C and C++ version

  3. A note about security!

  4. simple functions

   4.1 C Simple Functions

   4.2 C++ Simple Functions

  5. decoder

  6. encoder

  7. color conversions

  8. info values

  9. error values

  10. file IO

  11. chunks and PNG editing

  12. compiler support

  13. examples

   13.1. decoder example

   13.2. encoder example

  14. LodeZlib

  15. changes

  16. contact information

1. about

--------

PNG is a file format to store raster images losslessly with good compression,

supporting different color types. It can be implemented in a patent-free way.

LodePNG is a PNG codec according to the Portable Network Graphics (PNG)

Specification (Second Edition) - W3C Recommendation 10 November 2003.

The specifications used are:

*) Portable Network Graphics (PNG) Specification (Second Edition):

     http://www.w3.org/TR/2003/REC-PNG-20031110

*) RFC 1950 ZLIB Compressed Data Format version 3.3:

     http://www.gzip.org/zlib/rfc-zlib.html

*) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3:

     http://www.gzip.org/zlib/rfc-deflate.html

The most recent version of LodePNG can currently be found at

http://members.gamedev.net/lode/projects/LodePNG/

LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds

extra functionality.

LodePNG exists out of two files:

-lodepng.h: the header file for both C and C++

-lodepng.c(pp): give it the name lodepng.c or lodepng.cpp depending on your usage

If you want to start using LodePNG right away without reading this doc, get the

files lodepng_examples.c or lodepng_examples.cpp to see how to use it in code,

or check the (smaller) examples in chapter 13 here.

LodePNG is simple but only supports the basic requirements. To achieve

simplicity, the following design choices were made: There are no dependencies

on any external library. To decode PNGs, there's a Decoder struct or class that

can convert any PNG file data into an RGBA image buffer with a single function

call. To encode PNGs, there's an Encoder struct or class that can convert image

data into PNG file data with a single function call. To read and write files,

there are simple functions to convert the files to/from buffers in memory.

This all makes LodePNG suitable for loading textures in games, demoscene

productions, saving a screenshot, images in programs that require them for simple

usage, ... It's less suitable for full fledged image editors, loading PNGs

over network (it requires all the image data to be available before decoding can

begin), life-critical systems, ...

LodePNG has a standards conformant decoder and encoder, and supports the ability

to make a somewhat conformant editor.

1.1. supported features

-----------------------

The following features are supported by the decoder:

*) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image, or the same color type as the PNG

*) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image

*) Adam7 interlace and deinterlace for any color type

*) loading the image from harddisk or decoding it from a buffer from other sources than harddisk

*) support for alpha channels, including RGBA color model, translucent palettes and color keying

*) zlib decompression (inflate)

*) zlib compression (deflate)

*) CRC32 and ADLER32 checksums

*) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks.

*) the following chunks are supported (generated/interpreted) by both encoder and decoder:

    IHDR: header information

    PLTE: color palette

    IDAT: pixel data

    IEND: the final chunk

    tRNS: transparency for palettized images

    tEXt: textual information

    zTXt: compressed textual information

    iTXt: international textual information

    bKGD: suggested background color

    pHYs: physical dimensions

    tIME: modification time

1.2. features not supported

---------------------------

The following features are _not_ supported:

*) some features needed to make a conformant PNG-Editor might be still missing.

*) partial loading/stream processing. All data must be available and is processed in one call.

*) The following public chunks are not supported but treated as unknown chunks by LodePNG

    cHRM, gAMA, iCCP, sRGB, sBIT, hIST, sPLT

2. C and C++ version

--------------------

The C version uses buffers allocated with alloc instead that you need to free()

yourself. On top of that, you need to use init and cleanup functions for each

struct whenever using a struct from the C version to avoid exploits and memory leaks.

The C++ version has constructors and destructors that take care of these things,

and uses std::vectors in the interface for storing data.

Both the C and the C++ version are contained in this file! The C++ code depends on

the C code, the C code works on its own.

These files work without modification for both C and C++ compilers because all the

additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers ignore

it, and the C code is made to compile both with strict ISO C90 and C++.

To use the C++ version, you need to rename the source file to lodepng.cpp (instead

of lodepng.c), and compile it with a C++ compiler.

To use the C version, you need to rename the source file to lodepng.c (instead

of lodepng.cpp), and compile it with a C compiler.

3. A note about security!

-------------------------

Despite being used already and having received bug fixes whenever bugs were reported,

LodePNG may still contain possible exploits.