games/semicongine: semiconginev2/old/resources/lodepng.c comparison

comparison semiconginev2/old/resources/lodepng.c @ 1218:56781cc0fc7c compiletime-tests

did: renamge main package

author	sam <sam@basx.dev>
date	Wed, 17 Jul 2024 21:01:37 +0700
parents	semicongine/old/resources/lodepng.c@a3eb305bcac2
children

comparison

equal deleted inserted replaced

-:f819a874058f
+:56781cc0fc7c
+/*
+LodePNG version 20230410
+Copyright (c) 2005-2023 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.
+*/
+/*
+The manual and changelog are in the header file "lodepng.h"
+Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C.
+*/
+#include "lodepng.h"
+#ifdef LODEPNG_COMPILE_DISK
+#include <limits.h> /* LONG_MAX */
+#include <stdio.h> /* file handling */
+#endif /* LODEPNG_COMPILE_DISK */
+#ifdef LODEPNG_COMPILE_ALLOCATORS
+#include <stdlib.h> /* allocations */
+#endif /* LODEPNG_COMPILE_ALLOCATORS */
+#if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/
+#pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/
+#pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
+#endif /*_MSC_VER */
+const char* LODEPNG_VERSION_STRING = "20230410";
+/*
+This source file is divided into the following large parts. The code sections
+with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way.
+-Tools for C and common code for PNG and Zlib
+-C Code for Zlib (huffman, deflate, ...)
+-C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...)
+-The C++ wrapper around all of the above
+*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // Tools for C, and common code for PNG and Zlib.                       // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/*The malloc, realloc and free functions defined here with "lodepng_" in front
+of the name, so that you can easily change them to others related to your
+platform if needed. Everything else in the code calls these. Pass
+-DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out
+#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and
+define them in your own project's source files without needing to change
+lodepng source code. Don't forget to remove "static" if you copypaste them
+from here.*/
+#ifdef LODEPNG_COMPILE_ALLOCATORS
+static void* lodepng_malloc(size_t size) {
+#ifdef LODEPNG_MAX_ALLOC
+if(size > LODEPNG_MAX_ALLOC) return 0;
+#endif
+return malloc(size);
+}
+/* NOTE: when realloc returns NULL, it leaves the original memory untouched */
+static void* lodepng_realloc(void* ptr, size_t new_size) {
+#ifdef LODEPNG_MAX_ALLOC
+if(new_size > LODEPNG_MAX_ALLOC) return 0;
+#endif
+return realloc(ptr, new_size);
+}
+static void lodepng_free(void* ptr) {
+free(ptr);
+}
+#else /*LODEPNG_COMPILE_ALLOCATORS*/
+/* TODO: support giving additional void* payload to the custom allocators */
+void* lodepng_malloc(size_t size);
+void* lodepng_realloc(void* ptr, size_t new_size);
+void lodepng_free(void* ptr);
+#endif /*LODEPNG_COMPILE_ALLOCATORS*/
+/* convince the compiler to inline a function, for use when this measurably improves performance */
+/* inline is not available in C90, but use it when supported by the compiler */
+#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L))
+#define LODEPNG_INLINE inline
+#else
+#define LODEPNG_INLINE /* not available */
+#endif
+/* restrict is not available in C90, but use it when supported by the compiler */
+#if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\
+(defined(_MSC_VER) && (_MSC_VER >= 1400)) || \
+(defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus))
+#define LODEPNG_RESTRICT __restrict
+#else
+#define LODEPNG_RESTRICT /* not available */
+#endif
+/* Replacements for C library functions such as memcpy and strlen, to support platforms
+where a full C library is not available. The compiler can recognize them and compile
+to something as fast. */
+static void lodepng_memcpy(void* LODEPNG_RESTRICT dst,
+const void* LODEPNG_RESTRICT src, size_t size) {
+size_t i;
+for(i = 0; i < size; i++) ((char*)dst)[i] = ((const char*)src)[i];
+}
+static void lodepng_memset(void* LODEPNG_RESTRICT dst,
+int value, size_t num) {
+size_t i;
+for(i = 0; i < num; i++) ((char*)dst)[i] = (char)value;
+}
+/* does not check memory out of bounds, do not use on untrusted data */
+static size_t lodepng_strlen(const char* a) {
+const char* orig = a;
+/* avoid warning about unused function in case of disabled COMPILE... macros */
+(void)(&lodepng_strlen);
+while(*a) a++;
+return (size_t)(a - orig);
+}
+#define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b))
+#define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b))
+#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)
+/* Safely check if adding two integers will overflow (no undefined
+behavior, compiler removing the code, etc...) and output result. */
+static int lodepng_addofl(size_t a, size_t b, size_t* result) {
+*result = a + b; /* Unsigned addition is well defined and safe in C90 */
+return *result < a;
+}
+#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)*/
+#ifdef LODEPNG_COMPILE_DECODER
+/* Safely check if multiplying two integers will overflow (no undefined
+behavior, compiler removing the code, etc...) and output result. */
+static int lodepng_mulofl(size_t a, size_t b, size_t* result) {
+*result = a * b; /* Unsigned multiplication is well defined and safe in C90 */
+return (a != 0 && *result / a != b);
+}
+#ifdef LODEPNG_COMPILE_ZLIB
+/* Safely check if a + b > c, even if overflow could happen. */
+static int lodepng_gtofl(size_t a, size_t b, size_t c) {
+size_t d;
+if(lodepng_addofl(a, b, &d)) return 1;
+return d > c;
+}
+#endif /*LODEPNG_COMPILE_ZLIB*/
+#endif /*LODEPNG_COMPILE_DECODER*/
+/*
+Often in case of an error a value is assigned to a variable and then it breaks
+out of a loop (to go to the cleanup phase of a function). This macro does that.
+It makes the error handling code shorter and more readable.
+Example: if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83);
+*/
+#define CERROR_BREAK(errorvar, code){\
+errorvar = code;\
+break;\
+}
+/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/
+#define ERROR_BREAK(code) CERROR_BREAK(error, code)
+/*Set error var to the error code, and return it.*/
+#define CERROR_RETURN_ERROR(errorvar, code){\
+errorvar = code;\
+return code;\
+}
+/*Try the code, if it returns error, also return the error.*/
+#define CERROR_TRY_RETURN(call){\
+unsigned error = call;\
+if(error) return error;\
+}
+/*Set error var to the error code, and return from the void function.*/
+#define CERROR_RETURN(errorvar, code){\
+errorvar = code;\
+return;\
+}
+/*
+About uivector, ucvector and string:
+-All of them wrap dynamic arrays or text strings in a similar way.
+-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version.
+-The string tools are made to avoid problems with compilers that declare things like strncat as deprecated.
+-They're not used in the interface, only internally in this file as static functions.
+-As with many other structs in this file, the init and cleanup functions serve as ctor and dtor.
+*/
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_ENCODER
+/*dynamic vector of unsigned ints*/
+typedef struct uivector {
+unsigned* data;
+size_t size; /*size in number of unsigned longs*/
+size_t allocsize; /*allocated size in bytes*/
+} uivector;
+static void uivector_cleanup(void* p) {
+((uivector*)p)->size = ((uivector*)p)->allocsize = 0;
+lodepng_free(((uivector*)p)->data);
+((uivector*)p)->data = NULL;
+}
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned uivector_resize(uivector* p, size_t size) {
+size_t allocsize = size * sizeof(unsigned);
+if(allocsize > p->allocsize) {
+size_t newsize = allocsize + (p->allocsize >> 1u);
+void* data = lodepng_realloc(p->data, newsize);
+if(data) {
+p->allocsize = newsize;
+p->data = (unsigned*)data;
+}
+else return 0; /*error: not enough memory*/
+}
+p->size = size;
+return 1; /*success*/
+}
+static void uivector_init(uivector* p) {
+p->data = NULL;
+p->size = p->allocsize = 0;
+}
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned uivector_push_back(uivector* p, unsigned c) {
+if(!uivector_resize(p, p->size + 1)) return 0;
+p->data[p->size - 1] = c;
+return 1;
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_ZLIB*/
+/* /////////////////////////////////////////////////////////////////////////// */
+/*dynamic vector of unsigned chars*/
+typedef struct ucvector {
+unsigned char* data;
+size_t size; /*used size*/
+size_t allocsize; /*allocated size*/
+} ucvector;
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned ucvector_reserve(ucvector* p, size_t size) {
+if(size > p->allocsize) {
+size_t newsize = size + (p->allocsize >> 1u);
+void* data = lodepng_realloc(p->data, newsize);
+if(data) {
+p->allocsize = newsize;
+p->data = (unsigned char*)data;
+}
+else return 0; /*error: not enough memory*/
+}
+return 1; /*success*/
+}
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned ucvector_resize(ucvector* p, size_t size) {
+p->size = size;
+return ucvector_reserve(p, size);
+}
+static ucvector ucvector_init(unsigned char* buffer, size_t size) {
+ucvector v;
+v.data = buffer;
+v.allocsize = v.size = size;
+return v;
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_PNG
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*free string pointer and set it to NULL*/
+static void string_cleanup(char** out) {
+lodepng_free(*out);
+*out = NULL;
+}
+/*also appends null termination character*/
+static char* alloc_string_sized(const char* in, size_t insize) {
+char* out = (char*)lodepng_malloc(insize + 1);
+if(out) {
+lodepng_memcpy(out, in, insize);
+out[insize] = 0;
+}
+return out;
+}
+/* dynamically allocates a new string with a copy of the null terminated input text */
+static char* alloc_string(const char* in) {
+return alloc_string_sized(in, lodepng_strlen(in));
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+#endif /*LODEPNG_COMPILE_PNG*/
+/* ////////////////////////////////////////////////////////////////////////// */
+#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)
+static unsigned lodepng_read32bitInt(const unsigned char* buffer) {
+return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) |
+((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]);
+}
+#endif /*defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)*/
+#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)
+/*buffer must have at least 4 allocated bytes available*/
+static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) {
+buffer[0] = (unsigned char)((value >> 24) & 0xff);
+buffer[1] = (unsigned char)((value >> 16) & 0xff);
+buffer[2] = (unsigned char)((value >>  8) & 0xff);
+buffer[3] = (unsigned char)((value      ) & 0xff);
+}
+#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / File IO                                                                / */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_DISK
+/* returns negative value on error. This should be pure C compatible, so no fstat. */
+static long lodepng_filesize(const char* filename) {
+FILE* file;
+long size;
+file = fopen(filename, "rb");
+if(!file) return -1;
+if(fseek(file, 0, SEEK_END) != 0) {
+fclose(file);
+return -1;
+}
+size = ftell(file);
+/* It may give LONG_MAX as directory size, this is invalid for us. */
+if(size == LONG_MAX) size = -1;
+fclose(file);
+return size;
+}
+/* load file into buffer that already has the correct allocated size. Returns error code.*/
+static unsigned lodepng_buffer_file(unsigned char* out, size_t size, const char* filename) {
+FILE* file;
+size_t readsize;
+file = fopen(filename, "rb");
+if(!file) return 78;
+readsize = fread(out, 1, size, file);
+fclose(file);
+if(readsize != size) return 78;
+return 0;
+}
+unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) {
+long size = lodepng_filesize(filename);
+if(size < 0) return 78;
+*outsize = (size_t)size;
+*out = (unsigned char*)lodepng_malloc((size_t)size);
+if(!(*out) && size > 0) return 83; /*the above malloc failed*/
+return lodepng_buffer_file(*out, (size_t)size, filename);
+}
+/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
+unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) {
+FILE* file;
+file = fopen(filename, "wb" );
+if(!file) return 79;
+fwrite(buffer, 1, buffersize, file);
+fclose(file);
+return 0;
+}
+#endif /*LODEPNG_COMPILE_DISK*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // End of common code and tools. Begin of Zlib related code.            // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_ENCODER
+typedef struct {
+ucvector* data;
+unsigned char bp; /*ok to overflow, indicates bit pos inside byte*/
+} LodePNGBitWriter;
+static void LodePNGBitWriter_init(LodePNGBitWriter* writer, ucvector* data) {
+writer->data = data;
+writer->bp = 0;
+}
+/*TODO: this ignores potential out of memory errors*/
+#define WRITEBIT(writer, bit){\
+/* append new byte */\
+if(((writer->bp) & 7u) == 0) {\
+if(!ucvector_resize(writer->data, writer->data->size + 1)) return;\
+writer->data->data[writer->data->size - 1] = 0;\
+}\
+(writer->data->data[writer->data->size - 1]) |= (bit << ((writer->bp) & 7u));\
+++writer->bp;\
+}
+/* LSB of value is written first, and LSB of bytes is used first */
+static void writeBits(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
+if(nbits == 1) { /* compiler should statically compile this case if nbits == 1 */
+WRITEBIT(writer, value);
+} else {
+/* TODO: increase output size only once here rather than in each WRITEBIT */
+size_t i;
+for(i = 0; i != nbits; ++i) {
+WRITEBIT(writer, (unsigned char)((value >> i) & 1));
+}
+}
+}
+/* This one is to use for adding huffman symbol, the value bits are written MSB first */
+static void writeBitsReversed(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
+size_t i;
+for(i = 0; i != nbits; ++i) {
+/* TODO: increase output size only once here rather than in each WRITEBIT */
+WRITEBIT(writer, (unsigned char)((value >> (nbits - 1u - i)) & 1u));
+}
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#ifdef LODEPNG_COMPILE_DECODER
+typedef struct {
+const unsigned char* data;
+size_t size; /*size of data in bytes*/
+size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/
+size_t bp;
+unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/
+} LodePNGBitReader;
+/* data size argument is in bytes. Returns error if size too large causing overflow */
+static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, const unsigned char* data, size_t size) {
+size_t temp;
+reader->data = data;
+reader->size = size;
+/* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB)  */
+if(lodepng_mulofl(size, 8u, &reader->bitsize)) return 105;
+/*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and
+trying to ensure 32 more bits*/
+if(lodepng_addofl(reader->bitsize, 64u, &temp)) return 105;
+reader->bp = 0;
+reader->buffer = 0;
+return 0; /*ok*/
+}
+/*
+ensureBits functions:
+Ensures the reader can at least read nbits bits in one or more readBits calls,
+safely even if not enough bits are available.
+The nbits parameter is unused but is given for documentation purposes, error
+checking for amount of bits must be done beforehand.
+*/
+/*See ensureBits documentation above. This one ensures up to 9 bits */
+static LODEPNG_INLINE void ensureBits9(LodePNGBitReader* reader, size_t nbits) {
+size_t start = reader->bp >> 3u;
+size_t size = reader->size;
+if(start + 1u < size) {
+reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u);
+reader->buffer >>= (reader->bp & 7u);
+} else {
+reader->buffer = 0;
+if(start + 0u < size) reader->buffer = reader->data[start + 0];
+reader->buffer >>= (reader->bp & 7u);
+}
+(void)nbits;
+}
+/*See ensureBits documentation above. This one ensures up to 17 bits */
+static LODEPNG_INLINE void ensureBits17(LodePNGBitReader* reader, size_t nbits) {
+size_t start = reader->bp >> 3u;
+size_t size = reader->size;
+if(start + 2u < size) {
+reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
+((unsigned)reader->data[start + 2] << 16u);
+reader->buffer >>= (reader->bp & 7u);
+} else {
+reader->buffer = 0;
+if(start + 0u < size) reader->buffer |= reader->data[start + 0];
+if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
+reader->buffer >>= (reader->bp & 7u);
+}
+(void)nbits;
+}
+/*See ensureBits documentation above. This one ensures up to 25 bits */
+static LODEPNG_INLINE void ensureBits25(LodePNGBitReader* reader, size_t nbits) {
+size_t start = reader->bp >> 3u;
+size_t size = reader->size;
+if(start + 3u < size) {
+reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
+((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u);
+reader->buffer >>= (reader->bp & 7u);
+} else {
+reader->buffer = 0;
+if(start + 0u < size) reader->buffer |= reader->data[start + 0];
+if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
+if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u);
+reader->buffer >>= (reader->bp & 7u);
+}
+(void)nbits;
+}
+/*See ensureBits documentation above. This one ensures up to 32 bits */
+static LODEPNG_INLINE void ensureBits32(LodePNGBitReader* reader, size_t nbits) {
+size_t start = reader->bp >> 3u;
+size_t size = reader->size;
+if(start + 4u < size) {
+reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
+((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u);
+reader->buffer >>= (reader->bp & 7u);
+reader->buffer |= (((unsigned)reader->data[start + 4] << 24u) << (8u - (reader->bp & 7u)));
+} else {
+reader->buffer = 0;
+if(start + 0u < size) reader->buffer |= reader->data[start + 0];
+if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
+if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u);
+if(start + 3u < size) reader->buffer |= ((unsigned)reader->data[start + 3] << 24u);
+reader->buffer >>= (reader->bp & 7u);
+}
+(void)nbits;
+}
+/* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */
+static LODEPNG_INLINE unsigned peekBits(LodePNGBitReader* reader, size_t nbits) {
+/* The shift allows nbits to be only up to 31. */
+return reader->buffer & ((1u << nbits) - 1u);
+}
+/* Must have enough bits available with ensureBits */
+static LODEPNG_INLINE void advanceBits(LodePNGBitReader* reader, size_t nbits) {
+reader->buffer >>= nbits;
+reader->bp += nbits;
+}
+/* Must have enough bits available with ensureBits */
+static LODEPNG_INLINE unsigned readBits(LodePNGBitReader* reader, size_t nbits) {
+unsigned result = peekBits(reader, nbits);
+advanceBits(reader, nbits);
+return result;
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+static unsigned reverseBits(unsigned bits, unsigned num) {
+/*TODO: implement faster lookup table based version when needed*/
+unsigned i, result = 0;
+for(i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i;
+return result;
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Deflate - Huffman                                                      / */
+/* ////////////////////////////////////////////////////////////////////////// */
+#define FIRST_LENGTH_CODE_INDEX 257
+#define LAST_LENGTH_CODE_INDEX 285
+/*256 literals, the end code, some length codes, and 2 unused codes*/
+#define NUM_DEFLATE_CODE_SYMBOLS 288
+/*the distance codes have their own symbols, 30 used, 2 unused*/
+#define NUM_DISTANCE_SYMBOLS 32
+/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/
+#define NUM_CODE_LENGTH_CODES 19
+/*the base lengths represented by codes 257-285*/
+static const unsigned LENGTHBASE[29]
+= {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
+67, 83, 99, 115, 131, 163, 195, 227, 258};
+/*the extra bits used by codes 257-285 (added to base length)*/
+static const unsigned LENGTHEXTRA[29]
+= {0, 0, 0, 0, 0, 0, 0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  3,
+4,  4,  4,   4,   5,   5,   5,   5,   0};
+/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/
+static const unsigned DISTANCEBASE[30]
+= {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
+769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
+/*the extra bits of backwards distances (added to base)*/
+static const unsigned DISTANCEEXTRA[30]
+= {0, 0, 0, 0, 1, 1, 2,  2,  3,  3,  4,  4,  5,  5,   6,   6,   7,   7,   8,
+8,    9,    9,   10,   10,   11,   11,   12,    12,    13,    13};
+/*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman
+tree of the dynamic huffman tree lengths is generated*/
+static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES]
+= {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
+/* ////////////////////////////////////////////////////////////////////////// */
+/*
+Huffman tree struct, containing multiple representations of the tree
+*/
+typedef struct HuffmanTree {
+unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/
+unsigned* lengths; /*the lengths of the huffman codes*/
+unsigned maxbitlen; /*maximum number of bits a single code can get*/
+unsigned numcodes; /*number of symbols in the alphabet = number of codes*/
+/* for reading only */
+unsigned char* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/
+unsigned short* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/
+} HuffmanTree;
+static void HuffmanTree_init(HuffmanTree* tree) {
+tree->codes = 0;
+tree->lengths = 0;
+tree->table_len = 0;
+tree->table_value = 0;
+}
+static void HuffmanTree_cleanup(HuffmanTree* tree) {
+lodepng_free(tree->codes);
+lodepng_free(tree->lengths);
+lodepng_free(tree->table_len);
+lodepng_free(tree->table_value);
+}
+/* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/
+/* values 8u and 9u work the fastest */
+#define FIRSTBITS 9u
+/* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination,
+which is possible in case of only 0 or 1 present symbols. */
+#define INVALIDSYMBOL 65535u
+/* make table for huffman decoding */
+static unsigned HuffmanTree_makeTable(HuffmanTree* tree) {
+static const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/
+static const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u;
+size_t i, numpresent, pointer, size; /*total table size*/
+unsigned* maxlens = (unsigned*)lodepng_malloc(headsize * sizeof(unsigned));
+if(!maxlens) return 83; /*alloc fail*/
+/* compute maxlens: max total bit length of symbols sharing prefix in the first table*/
+lodepng_memset(maxlens, 0, headsize * sizeof(*maxlens));
+for(i = 0; i < tree->numcodes; i++) {
+unsigned symbol = tree->codes[i];
+unsigned l = tree->lengths[i];
+unsigned index;
+if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/
+/*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/
+index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS);
+maxlens[index] = LODEPNG_MAX(maxlens[index], l);
+}
+/* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */
+size = headsize;
+for(i = 0; i < headsize; ++i) {
+unsigned l = maxlens[i];
+if(l > FIRSTBITS) size += (1u << (l - FIRSTBITS));
+}
+tree->table_len = (unsigned char*)lodepng_malloc(size * sizeof(*tree->table_len));
+tree->table_value = (unsigned short*)lodepng_malloc(size * sizeof(*tree->table_value));
+if(!tree->table_len || !tree->table_value) {
+lodepng_free(maxlens);
+/* freeing tree->table values is done at a higher scope */
+return 83; /*alloc fail*/
+}
+/*initialize with an invalid length to indicate unused entries*/
+for(i = 0; i < size; ++i) tree->table_len[i] = 16;
+/*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/
+pointer = headsize;
+for(i = 0; i < headsize; ++i) {
+unsigned l = maxlens[i];
+if(l <= FIRSTBITS) continue;
+tree->table_len[i] = l;
+tree->table_value[i] = pointer;
+pointer += (1u << (l - FIRSTBITS));
+}
+lodepng_free(maxlens);
+/*fill in the first table for short symbols, or secondary table for long symbols*/
+numpresent = 0;
+for(i = 0; i < tree->numcodes; ++i) {
+unsigned l = tree->lengths[i];
+unsigned symbol, reverse;
+if(l == 0) continue;
+symbol = tree->codes[i]; /*the huffman bit pattern. i itself is the value.*/
+/*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/
+reverse = reverseBits(symbol, l);
+numpresent++;
+if(l <= FIRSTBITS) {
+/*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/
+unsigned num = 1u << (FIRSTBITS - l);
+unsigned j;
+for(j = 0; j < num; ++j) {
+/*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/
+unsigned index = reverse | (j << l);
+if(tree->table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
+tree->table_len[index] = l;
+tree->table_value[index] = i;
+}
+} else {
+/*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/
+/*the FIRSTBITS MSBs of the symbol are the first table index*/
+unsigned index = reverse & mask;
+unsigned maxlen = tree->table_len[index];
+/*log2 of secondary table length, should be >= l - FIRSTBITS*/
+unsigned tablelen = maxlen - FIRSTBITS;
+unsigned start = tree->table_value[index]; /*starting index in secondary table*/
+unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/
+unsigned j;
+if(maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
+for(j = 0; j < num; ++j) {
+unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */
+unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS)));
+tree->table_len[index2] = l;
+tree->table_value[index2] = i;
+}
+}
+}
+if(numpresent < 2) {
+/* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits,
+but deflate uses 1 bit instead. In case of 0 symbols, no symbols can
+appear at all, but such huffman tree could still exist (e.g. if distance
+codes are never used). In both cases, not all symbols of the table will be
+filled in. Fill them in with an invalid symbol value so returning them from
+huffmanDecodeSymbol will cause error. */
+for(i = 0; i < size; ++i) {
+if(tree->table_len[i] == 16) {
+/* As length, use a value smaller than FIRSTBITS for the head table,
+and a value larger than FIRSTBITS for the secondary table, to ensure
+valid behavior for advanceBits when reading this symbol. */
+tree->table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1);
+tree->table_value[i] = INVALIDSYMBOL;
+}
+}
+} else {
+/* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes.
+If that is not the case (due to too long length codes), the table will not
+have been fully used, and this is an error (not all bit combinations can be
+decoded): an oversubscribed huffman tree, indicated by error 55. */
+for(i = 0; i < size; ++i) {
+if(tree->table_len[i] == 16) return 55;
+}
+}
+return 0;
+}
+/*
+Second step for the ...makeFromLengths and ...makeFromFrequencies functions.
+numcodes, lengths and maxbitlen must already be filled in correctly. return
+value is error.
+*/
+static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) {
+unsigned* blcount;
+unsigned* nextcode;
+unsigned error = 0;
+unsigned bits, n;
+tree->codes = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned));
+blcount = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned));
+nextcode = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned));
+if(!tree->codes || !blcount || !nextcode) error = 83; /*alloc fail*/
+if(!error) {
+for(n = 0; n != tree->maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0;
+/*step 1: count number of instances of each code length*/
+for(bits = 0; bits != tree->numcodes; ++bits) ++blcount[tree->lengths[bits]];
+/*step 2: generate the nextcode values*/
+for(bits = 1; bits <= tree->maxbitlen; ++bits) {
+nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u;
+}
+/*step 3: generate all the codes*/
+for(n = 0; n != tree->numcodes; ++n) {
+if(tree->lengths[n] != 0) {
+tree->codes[n] = nextcode[tree->lengths[n]]++;
+/*remove superfluous bits from the code*/
+tree->codes[n] &= ((1u << tree->lengths[n]) - 1u);
+}
+}
+}
+lodepng_free(blcount);
+lodepng_free(nextcode);
+if(!error) error = HuffmanTree_makeTable(tree);
+return error;
+}
+/*
+given the code lengths (as stored in the PNG file), generate the tree as defined
+by Deflate. maxbitlen is the maximum bits that a code in the tree can have.
+return value is error.
+*/
+static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen,
+size_t numcodes, unsigned maxbitlen) {
+unsigned i;
+tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
+if(!tree->lengths) return 83; /*alloc fail*/
+for(i = 0; i != numcodes; ++i) tree->lengths[i] = bitlen[i];
+tree->numcodes = (unsigned)numcodes; /*number of symbols*/
+tree->maxbitlen = maxbitlen;
+return HuffmanTree_makeFromLengths2(tree);
+}
+#ifdef LODEPNG_COMPILE_ENCODER
+/*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding",
+Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/
+/*chain node for boundary package merge*/
+typedef struct BPMNode {
+int weight; /*the sum of all weights in this chain*/
+unsigned index; /*index of this leaf node (called "count" in the paper)*/
+struct BPMNode* tail; /*the next nodes in this chain (null if last)*/
+int in_use;
+} BPMNode;
+/*lists of chains*/
+typedef struct BPMLists {
+/*memory pool*/
+unsigned memsize;
+BPMNode* memory;
+unsigned numfree;
+unsigned nextfree;
+BPMNode** freelist;
+/*two heads of lookahead chains per list*/
+unsigned listsize;
+BPMNode** chains0;
+BPMNode** chains1;
+} BPMLists;
+/*creates a new chain node with the given parameters, from the memory in the lists */
+static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) {
+unsigned i;
+BPMNode* result;
+/*memory full, so garbage collect*/
+if(lists->nextfree >= lists->numfree) {
+/*mark only those that are in use*/
+for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0;
+for(i = 0; i != lists->listsize; ++i) {
+BPMNode* node;
+for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1;
+for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1;
+}
+/*collect those that are free*/
+lists->numfree = 0;
+for(i = 0; i != lists->memsize; ++i) {
+if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i];
+}
+lists->nextfree = 0;
+}
+result = lists->freelist[lists->nextfree++];
+result->weight = weight;
+result->index = index;
+result->tail = tail;
+return result;
+}
+/*sort the leaves with stable mergesort*/
+static void bpmnode_sort(BPMNode* leaves, size_t num) {
+BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num);
+size_t width, counter = 0;
+for(width = 1; width < num; width *= 2) {
+BPMNode* a = (counter & 1) ? mem : leaves;
+BPMNode* b = (counter & 1) ? leaves : mem;
+size_t p;
+for(p = 0; p < num; p += 2 * width) {
+size_t q = (p + width > num) ? num : (p + width);
+size_t r = (p + 2 * width > num) ? num : (p + 2 * width);
+size_t i = p, j = q, k;
+for(k = p; k < r; k++) {
+if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++];
+else b[k] = a[j++];
+}
+}
+counter++;
+}
+if(counter & 1) lodepng_memcpy(leaves, mem, sizeof(*leaves) * num);
+lodepng_free(mem);
+}
+/*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/
+static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) {
+unsigned lastindex = lists->chains1[c]->index;
+if(c == 0) {
+if(lastindex >= numpresent) return;
+lists->chains0[c] = lists->chains1[c];
+lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0);
+} else {
+/*sum of the weights of the head nodes of the previous lookahead chains.*/
+int sum = lists->chains0[c - 1]->weight + lists->chains1[c - 1]->weight;
+lists->chains0[c] = lists->chains1[c];
+if(lastindex < numpresent && sum > leaves[lastindex].weight) {
+lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists->chains1[c]->tail);
+return;
+}
+lists->chains1[c] = bpmnode_create(lists, sum, lastindex, lists->chains1[c - 1]);
+/*in the end we are only interested in the chain of the last list, so no
+need to recurse if we're at the last one (this gives measurable speedup)*/
+if(num + 1 < (int)(2 * numpresent - 2)) {
+boundaryPM(lists, leaves, numpresent, c - 1, num);
+boundaryPM(lists, leaves, numpresent, c - 1, num);
+}
+}
+}
+unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
+size_t numcodes, unsigned maxbitlen) {
+unsigned error = 0;
+unsigned i;
+size_t numpresent = 0; /*number of symbols with non-zero frequency*/
+BPMNode* leaves; /*the symbols, only those with > 0 frequency*/
+if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/
+if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/
+leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves));
+if(!leaves) return 83; /*alloc fail*/
+for(i = 0; i != numcodes; ++i) {
+if(frequencies[i] > 0) {
+leaves[numpresent].weight = (int)frequencies[i];
+leaves[numpresent].index = i;
+++numpresent;
+}
+}
+lodepng_memset(lengths, 0, numcodes * sizeof(*lengths));
+/*ensure at least two present symbols. There should be at least one symbol
+according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To
+make these work as well ensure there are at least two symbols. The
+Package-Merge code below also doesn't work correctly if there's only one
+symbol, it'd give it the theoretical 0 bits but in practice zlib wants 1 bit*/
+if(numpresent == 0) {
+lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/
+} else if(numpresent == 1) {
+lengths[leaves[0].index] = 1;
+lengths[leaves[0].index == 0 ? 1 : 0] = 1;
+} else {
+BPMLists lists;
+BPMNode* node;
+bpmnode_sort(leaves, numpresent);
+lists.listsize = maxbitlen;
+lists.memsize = 2 * maxbitlen * (maxbitlen + 1);
+lists.nextfree = 0;
+lists.numfree = lists.memsize;
+lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory));
+lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*));
+lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
+lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
+if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/
+if(!error) {
+for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i];
+bpmnode_create(&lists, leaves[0].weight, 1, 0);
+bpmnode_create(&lists, leaves[1].weight, 2, 0);
+for(i = 0; i != lists.listsize; ++i) {
+lists.chains0[i] = &lists.memory[0];
+lists.chains1[i] = &lists.memory[1];
+}
+/*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/
+for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i);
+for(node = lists.chains1[maxbitlen - 1]; node; node = node->tail) {
+for(i = 0; i != node->index; ++i) ++lengths[leaves[i].index];
+}
+}
+lodepng_free(lists.memory);
+lodepng_free(lists.freelist);
+lodepng_free(lists.chains0);
+lodepng_free(lists.chains1);
+}
+lodepng_free(leaves);
+return error;
+}
+/*Create the Huffman tree given the symbol frequencies*/
+static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies,
+size_t mincodes, size_t numcodes, unsigned maxbitlen) {
+unsigned error = 0;
+while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/
+tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
+if(!tree->lengths) return 83; /*alloc fail*/
+tree->maxbitlen = maxbitlen;
+tree->numcodes = (unsigned)numcodes; /*number of symbols*/
+error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen);
+if(!error) error = HuffmanTree_makeFromLengths2(tree);
+return error;
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/
+static unsigned generateFixedLitLenTree(HuffmanTree* tree) {
+unsigned i, error = 0;
+unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
+if(!bitlen) return 83; /*alloc fail*/
+/*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/
+for(i =   0; i <= 143; ++i) bitlen[i] = 8;
+for(i = 144; i <= 255; ++i) bitlen[i] = 9;
+for(i = 256; i <= 279; ++i) bitlen[i] = 7;
+for(i = 280; i <= 287; ++i) bitlen[i] = 8;
+error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15);
+lodepng_free(bitlen);
+return error;
+}
+/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/
+static unsigned generateFixedDistanceTree(HuffmanTree* tree) {
+unsigned i, error = 0;
+unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
+if(!bitlen) return 83; /*alloc fail*/
+/*there are 32 distance codes, but 30-31 are unused*/
+for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5;
+error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15);
+lodepng_free(bitlen);
+return error;
+}
+#ifdef LODEPNG_COMPILE_DECODER
+/*
+returns the code. The bit reader must already have been ensured at least 15 bits
+*/
+static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, const HuffmanTree* codetree) {
+unsigned short code = peekBits(reader, FIRSTBITS);
+unsigned short l = codetree->table_len[code];
+unsigned short value = codetree->table_value[code];
+if(l <= FIRSTBITS) {
+advanceBits(reader, l);
+return value;
+} else {
+advanceBits(reader, FIRSTBITS);
+value += peekBits(reader, l - FIRSTBITS);
+advanceBits(reader, codetree->table_len[value] - FIRSTBITS);
+return codetree->table_value[value];
+}
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_DECODER
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Inflator (Decompressor)                                                / */
+/* ////////////////////////////////////////////////////////////////////////// */
+/*get the tree of a deflated block with fixed tree, as specified in the deflate specification
+Returns error code.*/
+static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) {
+unsigned error = generateFixedLitLenTree(tree_ll);
+if(error) return error;
+return generateFixedDistanceTree(tree_d);
+}
+/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/
+static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d,
+LodePNGBitReader* reader) {
+/*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/
+unsigned error = 0;
+unsigned n, HLIT, HDIST, HCLEN, i;
+/*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/
+unsigned* bitlen_ll = 0; /*lit,len code lengths*/
+unsigned* bitlen_d = 0; /*dist code lengths*/
+/*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/
+unsigned* bitlen_cl = 0;
+HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/
+if(reader->bitsize - reader->bp < 14) return 49; /*error: the bit pointer is or will go past the memory*/
+ensureBits17(reader, 14);
+/*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/
+HLIT =  readBits(reader, 5) + 257;
+/*number of distance codes. Unlike the spec, the value 1 is added to it here already*/
+HDIST = readBits(reader, 5) + 1;
+/*number of code length codes. Unlike the spec, the value 4 is added to it here already*/
+HCLEN = readBits(reader, 4) + 4;
+bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned));
+if(!bitlen_cl) return 83 /*alloc fail*/;
+HuffmanTree_init(&tree_cl);
+while(!error) {
+/*read the code length codes out of 3 * (amount of code length codes) bits*/
+if(lodepng_gtofl(reader->bp, HCLEN * 3, reader->bitsize)) {
+ERROR_BREAK(50); /*error: the bit pointer is or will go past the memory*/
+}
+for(i = 0; i != HCLEN; ++i) {
+ensureBits9(reader, 3); /*out of bounds already checked above */
+bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3);
+}
+for(i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) {
+bitlen_cl[CLCL_ORDER[i]] = 0;
+}
+error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7);
+if(error) break;
+/*now we can use this tree to read the lengths for the tree that this function will return*/
+bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
+bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
+if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/);
+lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(*bitlen_ll));
+lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(*bitlen_d));
+/*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/
+i = 0;
+while(i < HLIT + HDIST) {
+unsigned code;
+ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/
+code = huffmanDecodeSymbol(reader, &tree_cl);
+if(code <= 15) /*a length code*/ {
+if(i < HLIT) bitlen_ll[i] = code;
+else bitlen_d[i - HLIT] = code;
+++i;
+} else if(code == 16) /*repeat previous*/ {
+unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/
+unsigned value; /*set value to the previous code*/
+if(i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/
+replength += readBits(reader, 2);
+if(i < HLIT + 1) value = bitlen_ll[i - 1];
+else value = bitlen_d[i - HLIT - 1];
+/*repeat this value in the next lengths*/
+for(n = 0; n < replength; ++n) {
+if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/
+if(i < HLIT) bitlen_ll[i] = value;
+else bitlen_d[i - HLIT] = value;
+++i;
+}
+} else if(code == 17) /*repeat "0" 3-10 times*/ {
+unsigned replength = 3; /*read in the bits that indicate repeat length*/
+replength += readBits(reader, 3);
+/*repeat this value in the next lengths*/
+for(n = 0; n < replength; ++n) {
+if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/
+if(i < HLIT) bitlen_ll[i] = 0;
+else bitlen_d[i - HLIT] = 0;
+++i;
+}
+} else if(code == 18) /*repeat "0" 11-138 times*/ {
+unsigned replength = 11; /*read in the bits that indicate repeat length*/
+replength += readBits(reader, 7);
+/*repeat this value in the next lengths*/
+for(n = 0; n < replength; ++n) {
+if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/
+if(i < HLIT) bitlen_ll[i] = 0;
+else bitlen_d[i - HLIT] = 0;
+++i;
+}
+} else /*if(code == INVALIDSYMBOL)*/ {
+ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
+}
+/*check if any of the ensureBits above went out of bounds*/
+if(reader->bp > reader->bitsize) {
+/*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
+(10=no endcode, 11=wrong jump outside of tree)*/
+/* TODO: revise error codes 10,11,50: the above comment is no longer valid */
+ERROR_BREAK(50); /*error, bit pointer jumps past memory*/
+}
+}
+if(error) break;
+if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/
+/*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/
+error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15);
+if(error) break;
+error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15);
+break; /*end of error-while*/
+}
+lodepng_free(bitlen_cl);
+lodepng_free(bitlen_ll);
+lodepng_free(bitlen_d);
+HuffmanTree_cleanup(&tree_cl);
+return error;
+}
+/*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/
+static unsigned inflateHuffmanBlock(ucvector* out, LodePNGBitReader* reader,
+unsigned btype, size_t max_output_size) {
+unsigned error = 0;
+HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/
+HuffmanTree tree_d; /*the huffman tree for distance codes*/
+const size_t reserved_size = 260; /* must be at least 258 for max length, and a few extra for adding a few extra literals */
+int done = 0;
+if(!ucvector_reserve(out, out->size + reserved_size)) return 83; /*alloc fail*/
+HuffmanTree_init(&tree_ll);
+HuffmanTree_init(&tree_d);
+if(btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d);
+else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader);
+while(!error && !done) /*decode all symbols until end reached, breaks at end code*/ {
+/*code_ll is literal, length or end code*/
+unsigned code_ll;
+/* ensure enough bits for 2 huffman code reads (15 bits each): if the first is a literal, a second literal is read at once. This
+appears to be slightly faster, than ensuring 20 bits here for 1 huffman symbol and the potential 5 extra bits for the length symbol.*/
+ensureBits32(reader, 30);
+code_ll = huffmanDecodeSymbol(reader, &tree_ll);
+if(code_ll <= 255) {
+/*slightly faster code path if multiple literals in a row*/
+out->data[out->size++] = (unsigned char)code_ll;
+code_ll = huffmanDecodeSymbol(reader, &tree_ll);
+}
+if(code_ll <= 255) /*literal symbol*/ {
+out->data[out->size++] = (unsigned char)code_ll;
+} else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ {
+unsigned code_d, distance;
+unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/
+size_t start, backward, length;
+/*part 1: get length base*/
+length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX];
+/*part 2: get extra bits and add the value of that to length*/
+numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX];
+if(numextrabits_l != 0) {
+/* bits already ensured above */
+ensureBits25(reader, 5);
+length += readBits(reader, numextrabits_l);
+}
+/*part 3: get distance code*/
+ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */
+code_d = huffmanDecodeSymbol(reader, &tree_d);
+if(code_d > 29) {
+if(code_d <= 31) {
+ERROR_BREAK(18); /*error: invalid distance code (30-31 are never used)*/
+} else /* if(code_d == INVALIDSYMBOL) */{
+ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
+}
+}
+distance = DISTANCEBASE[code_d];
+/*part 4: get extra bits from distance*/
+numextrabits_d = DISTANCEEXTRA[code_d];
+if(numextrabits_d != 0) {
+/* bits already ensured above */
+distance += readBits(reader, numextrabits_d);
+}
+/*part 5: fill in all the out[n] values based on the length and dist*/
+start = out->size;
+if(distance > start) ERROR_BREAK(52); /*too long backward distance*/
+backward = start - distance;
+out->size += length;
+if(distance < length) {
+size_t forward;
+lodepng_memcpy(out->data + start, out->data + backward, distance);
+start += distance;
+for(forward = distance; forward < length; ++forward) {
+out->data[start++] = out->data[backward++];
+}
+} else {
+lodepng_memcpy(out->data + start, out->data + backward, length);
+}
+} else if(code_ll == 256) {
+done = 1; /*end code, finish the loop*/
+} else /*if(code_ll == INVALIDSYMBOL)*/ {
+ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
+}
+if(out->allocsize - out->size < reserved_size) {
+if(!ucvector_reserve(out, out->size + reserved_size)) ERROR_BREAK(83); /*alloc fail*/
+}
+/*check if any of the ensureBits above went out of bounds*/
+if(reader->bp > reader->bitsize) {
+/*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
+(10=no endcode, 11=wrong jump outside of tree)*/
+/* TODO: revise error codes 10,11,50: the above comment is no longer valid */
+ERROR_BREAK(51); /*error, bit pointer jumps past memory*/
+}
+if(max_output_size && out->size > max_output_size) {
+ERROR_BREAK(109); /*error, larger than max size*/
+}
+}
+HuffmanTree_cleanup(&tree_ll);
+HuffmanTree_cleanup(&tree_d);
+return error;
+}
+static unsigned inflateNoCompression(ucvector* out, LodePNGBitReader* reader,
+const LodePNGDecompressSettings* settings) {
+size_t bytepos;
+size_t size = reader->size;
+unsigned LEN, NLEN, error = 0;
+/*go to first boundary of byte*/
+bytepos = (reader->bp + 7u) >> 3u;
+/*read LEN (2 bytes) and NLEN (2 bytes)*/
+if(bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/
+LEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2;
+NLEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2;
+/*check if 16-bit NLEN is really the one's complement of LEN*/
+if(!settings->ignore_nlen && LEN + NLEN != 65535) {
+return 21; /*error: NLEN is not one's complement of LEN*/
+}
+if(!ucvector_resize(out, out->size + LEN)) return 83; /*alloc fail*/
+/*read the literal data: LEN bytes are now stored in the out buffer*/
+if(bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/
+/*out->data can be NULL (when LEN is zero), and arithmetics on NULL ptr is undefined*/
+if (LEN) {
+lodepng_memcpy(out->data + out->size - LEN, reader->data + bytepos, LEN);
+bytepos += LEN;
+}
+reader->bp = bytepos << 3u;
+return error;
+}
+static unsigned lodepng_inflatev(ucvector* out,
+const unsigned char* in, size_t insize,
+const LodePNGDecompressSettings* settings) {
+unsigned BFINAL = 0;
+LodePNGBitReader reader;
+unsigned error = LodePNGBitReader_init(&reader, in, insize);
+if(error) return error;
+while(!BFINAL) {
+unsigned BTYPE;
+if(reader.bitsize - reader.bp < 3) return 52; /*error, bit pointer will jump past memory*/
+ensureBits9(&reader, 3);
+BFINAL = readBits(&reader, 1);
+BTYPE = readBits(&reader, 2);
+if(BTYPE == 3) return 20; /*error: invalid BTYPE*/
+else if(BTYPE == 0) error = inflateNoCompression(out, &reader, settings); /*no compression*/
+else error = inflateHuffmanBlock(out, &reader, BTYPE, settings->max_output_size); /*compression, BTYPE 01 or 10*/
+if(!error && settings->max_output_size && out->size > settings->max_output_size) error = 109;
+if(error) break;
+}
+return error;
+}
+unsigned lodepng_inflate(unsigned char** out, size_t* outsize,
+const unsigned char* in, size_t insize,
+const LodePNGDecompressSettings* settings) {
+ucvector v = ucvector_init(*out, *outsize);
+unsigned error = lodepng_inflatev(&v, in, insize, settings);
+*out = v.data;
+*outsize = v.size;
+return error;
+}
+static unsigned inflatev(ucvector* out, const unsigned char* in, size_t insize,
+const LodePNGDecompressSettings* settings) {
+if(settings->custom_inflate) {
+unsigned error = settings->custom_inflate(&out->data, &out->size, in, insize, settings);
+out->allocsize = out->size;
+if(error) {
+/*the custom inflate is allowed to have its own error codes, however, we translate it to code 110*/
+error = 110;
+/*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
+if(settings->max_output_size && out->size > settings->max_output_size) error = 109;
+}
+return error;
+} else {
+return lodepng_inflatev(out, in, insize, settings);
+}
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Deflator (Compressor)                                                  / */
+/* ////////////////////////////////////////////////////////////////////////// */
+static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258;
+/*search the index in the array, that has the largest value smaller than or equal to the given value,
+given array must be sorted (if no value is smaller, it returns the size of the given array)*/
+static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) {
+/*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/
+size_t left = 1;
+size_t right = array_size - 1;
+while(left <= right) {
+size_t mid = (left + right) >> 1;
+if(array[mid] >= value) right = mid - 1;
+else left = mid + 1;
+}
+if(left >= array_size || array[left] > value) left--;
+return left;
+}
+static void addLengthDistance(uivector* values, size_t length, size_t distance) {
+/*values in encoded vector are those used by deflate:
+0-255: literal bytes
+256: end
+257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits)
+286-287: invalid*/
+unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length);
+unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]);
+unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance);
+unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]);
+size_t pos = values->size;
+/*TODO: return error when this fails (out of memory)*/
+unsigned ok = uivector_resize(values, values->size + 4);
+if(ok) {
+values->data[pos + 0] = length_code + FIRST_LENGTH_CODE_INDEX;
+values->data[pos + 1] = extra_length;
+values->data[pos + 2] = dist_code;
+values->data[pos + 3] = extra_distance;
+}
+}
+/*3 bytes of data get encoded into two bytes. The hash cannot use more than 3
+bytes as input because 3 is the minimum match length for deflate*/
+static const unsigned HASH_NUM_VALUES = 65536;
+static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/
+typedef struct Hash {
+int* head; /*hash value to head circular pos - can be outdated if went around window*/
+/*circular pos to prev circular pos*/
+unsigned short* chain;
+int* val; /*circular pos to hash value*/
+/*TODO: do this not only for zeros but for any repeated byte. However for PNG
+it's always going to be the zeros that dominate, so not important for PNG*/
+int* headz; /*similar to head, but for chainz*/
+unsigned short* chainz; /*those with same amount of zeros*/
+unsigned short* zeros; /*length of zeros streak, used as a second hash chain*/
+} Hash;
+static unsigned hash_init(Hash* hash, unsigned windowsize) {
+unsigned i;
+hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES);
+hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize);
+hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
+hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
+hash->headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1));
+hash->chainz = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
+if(!hash->head || !hash->chain || !hash->val  || !hash->headz|| !hash->chainz || !hash->zeros) {
+return 83; /*alloc fail*/
+}
+/*initialize hash table*/
+for(i = 0; i != HASH_NUM_VALUES; ++i) hash->head[i] = -1;
+for(i = 0; i != windowsize; ++i) hash->val[i] = -1;
+for(i = 0; i != windowsize; ++i) hash->chain[i] = i; /*same value as index indicates uninitialized*/
+for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash->headz[i] = -1;
+for(i = 0; i != windowsize; ++i) hash->chainz[i] = i; /*same value as index indicates uninitialized*/
+return 0;
+}
+static void hash_cleanup(Hash* hash) {
+lodepng_free(hash->head);
+lodepng_free(hash->val);
+lodepng_free(hash->chain);
+lodepng_free(hash->zeros);
+lodepng_free(hash->headz);
+lodepng_free(hash->chainz);
+}
+static unsigned getHash(const unsigned char* data, size_t size, size_t pos) {
+unsigned result = 0;
+if(pos + 2 < size) {
+/*A simple shift and xor hash is used. Since the data of PNGs is dominated
+by zeroes due to the filters, a better hash does not have a significant
+effect on speed in traversing the chain, and causes more time spend on
+calculating the hash.*/
+result ^= ((unsigned)data[pos + 0] << 0u);
+result ^= ((unsigned)data[pos + 1] << 4u);
+result ^= ((unsigned)data[pos + 2] << 8u);
+} else {
+size_t amount, i;
+if(pos >= size) return 0;
+amount = size - pos;
+for(i = 0; i != amount; ++i) result ^= ((unsigned)data[pos + i] << (i * 8u));
+}
+return result & HASH_BIT_MASK;
+}
+static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) {
+const unsigned char* start = data + pos;
+const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH;
+if(end > data + size) end = data + size;
+data = start;
+while(data != end && *data == 0) ++data;
+/*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/
+return (unsigned)(data - start);
+}
+/*wpos = pos & (windowsize - 1)*/
+static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros) {
+hash->val[wpos] = (int)hashval;
+if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval];
+hash->head[hashval] = (int)wpos;
+hash->zeros[wpos] = numzeros;
+if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros];
+hash->headz[numzeros] = (int)wpos;
+}
+/*
+LZ77-encode the data. Return value is error code. The input are raw bytes, the output
+is in the form of unsigned integers with codes representing for example literal bytes, or
+length/distance pairs.
+It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a
+sliding window (of windowsize) is used, and all past bytes in that window can be used as
+the "dictionary". A brute force search through all possible distances would be slow, and
+this hash technique is one out of several ways to speed this up.
+*/
+static unsigned encodeLZ77(uivector* out, Hash* hash,
+const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize,
+unsigned minmatch, unsigned nicematch, unsigned lazymatching) {
+size_t pos;
+unsigned i, error = 0;
+/*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/
+unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8u;
+unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64;
+unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/
+unsigned numzeros = 0;
+unsigned offset; /*the offset represents the distance in LZ77 terminology*/
+unsigned length;
+unsigned lazy = 0;
+unsigned lazylength = 0, lazyoffset = 0;
+unsigned hashval;
+unsigned current_offset, current_length;
+unsigned prev_offset;
+const unsigned char *lastptr, *foreptr, *backptr;
+unsigned hashpos;
+if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/
+if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/
+if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH;
+for(pos = inpos; pos < insize; ++pos) {
+size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/
+unsigned chainlength = 0;
+hashval = getHash(in, insize, pos);
+if(usezeros && hashval == 0) {
+if(numzeros == 0) numzeros = countZeros(in, insize, pos);
+else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
+} else {
+numzeros = 0;
+}
+updateHashChain(hash, wpos, hashval, numzeros);
+/*the length and offset found for the current position*/
+length = 0;
+offset = 0;
+hashpos = hash->chain[wpos];
+lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH];
+/*search for the longest string*/
+prev_offset = 0;
+for(;;) {
+if(chainlength++ >= maxchainlength) break;
+current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize);
+if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/
+prev_offset = current_offset;
+if(current_offset > 0) {
+/*test the next characters*/
+foreptr = &in[pos];
+backptr = &in[pos - current_offset];
+/*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/
+if(numzeros >= 3) {
+unsigned skip = hash->zeros[hashpos];
+if(skip > numzeros) skip = numzeros;
+backptr += skip;
+foreptr += skip;
+}
+while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ {
+++backptr;
+++foreptr;
+}
+current_length = (unsigned)(foreptr - &in[pos]);
+if(current_length > length) {
+length = current_length; /*the longest length*/
+offset = current_offset; /*the offset that is related to this longest length*/
+/*jump out once a length of max length is found (speed gain). This also jumps
+out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/
+if(current_length >= nicematch) break;
+}
+}
+if(hashpos == hash->chain[hashpos]) break;
+if(numzeros >= 3 && length > numzeros) {
+hashpos = hash->chainz[hashpos];
+if(hash->zeros[hashpos] != numzeros) break;
+} else {
+hashpos = hash->chain[hashpos];
+/*outdated hash value, happens if particular value was not encountered in whole last window*/
+if(hash->val[hashpos] != (int)hashval) break;
+}
+}
+if(lazymatching) {
+if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) {
+lazy = 1;
+lazylength = length;
+lazyoffset = offset;
+continue; /*try the next byte*/
+}
+if(lazy) {
+lazy = 0;
+if(pos == 0) ERROR_BREAK(81);
+if(length > lazylength + 1) {
+/*push the previous character as literal*/
+if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/);
+} else {
+length = lazylength;
+offset = lazyoffset;
+hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/
+hash->headz[numzeros] = -1; /*idem*/
+--pos;
+}
+}
+}
+if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/);
+/*encode it as length/distance pair or literal value*/
+if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ {
+if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
+} else if(length < minmatch || (length == 3 && offset > 4096)) {
+/*compensate for the fact that longer offsets have more extra bits, a
+length of only 3 may be not worth it then*/
+if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
+} else {
+addLengthDistance(out, length, offset);
+for(i = 1; i < length; ++i) {
+++pos;
+wpos = pos & (windowsize - 1);
+hashval = getHash(in, insize, pos);
+if(usezeros && hashval == 0) {
+if(numzeros == 0) numzeros = countZeros(in, insize, pos);
+else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
+} else {
+numzeros = 0;
+}
+updateHashChain(hash, wpos, hashval, numzeros);
+}
+}
+} /*end of the loop through each character of input*/
+return error;
+}
+/* /////////////////////////////////////////////////////////////////////////// */
+static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) {
+/*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte,
+2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/
+size_t i, numdeflateblocks = (datasize + 65534u) / 65535u;
+unsigned datapos = 0;
+for(i = 0; i != numdeflateblocks; ++i) {
+unsigned BFINAL, BTYPE, LEN, NLEN;
+unsigned char firstbyte;
+size_t pos = out->size;
+BFINAL = (i == numdeflateblocks - 1);
+BTYPE = 0;
+LEN = 65535;
+if(datasize - datapos < 65535u) LEN = (unsigned)datasize - datapos;
+NLEN = 65535 - LEN;
+if(!ucvector_resize(out, out->size + LEN + 5)) return 83; /*alloc fail*/
+firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1u) << 1u) + ((BTYPE & 2u) << 1u));
+out->data[pos + 0] = firstbyte;
+out->data[pos + 1] = (unsigned char)(LEN & 255);
+out->data[pos + 2] = (unsigned char)(LEN >> 8u);
+out->data[pos + 3] = (unsigned char)(NLEN & 255);
+out->data[pos + 4] = (unsigned char)(NLEN >> 8u);
+lodepng_memcpy(out->data + pos + 5, data + datapos, LEN);
+datapos += LEN;
+}
+return 0;
+}
+/*
+write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees.
+tree_ll: the tree for lit and len codes.
+tree_d: the tree for distance codes.
+*/
+static void writeLZ77data(LodePNGBitWriter* writer, const uivector* lz77_encoded,
+const HuffmanTree* tree_ll, const HuffmanTree* tree_d) {
+size_t i = 0;
+for(i = 0; i != lz77_encoded->size; ++i) {
+unsigned val = lz77_encoded->data[i];
+writeBitsReversed(writer, tree_ll->codes[val], tree_ll->lengths[val]);
+if(val > 256) /*for a length code, 3 more things have to be added*/ {
+unsigned length_index = val - FIRST_LENGTH_CODE_INDEX;
+unsigned n_length_extra_bits = LENGTHEXTRA[length_index];
+unsigned length_extra_bits = lz77_encoded->data[++i];
+unsigned distance_code = lz77_encoded->data[++i];
+unsigned distance_index = distance_code;
+unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index];
+unsigned distance_extra_bits = lz77_encoded->data[++i];
+writeBits(writer, length_extra_bits, n_length_extra_bits);
+writeBitsReversed(writer, tree_d->codes[distance_code], tree_d->lengths[distance_code]);
+writeBits(writer, distance_extra_bits, n_distance_extra_bits);
+}
+}
+}
+/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/
+static unsigned deflateDynamic(LodePNGBitWriter* writer, Hash* hash,
+const unsigned char* data, size_t datapos, size_t dataend,
+const LodePNGCompressSettings* settings, unsigned final) {
+unsigned error = 0;
+/*
+A block is compressed as follows: The PNG data is lz77 encoded, resulting in
+literal bytes and length/distance pairs. This is then huffman compressed with
+two huffman trees. One huffman tree is used for the lit and len values ("ll"),
+another huffman tree is used for the dist values ("d"). These two trees are
+stored using their code lengths, and to compress even more these code lengths
+are also run-length encoded and huffman compressed. This gives a huffman tree
+of code lengths "cl". The code lengths used to describe this third tree are
+the code length code lengths ("clcl").
+*/
+/*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/
+uivector lz77_encoded;
+HuffmanTree tree_ll; /*tree for lit,len values*/
+HuffmanTree tree_d; /*tree for distance codes*/
+HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/
+unsigned* frequencies_ll = 0; /*frequency of lit,len codes*/
+unsigned* frequencies_d = 0; /*frequency of dist codes*/
+unsigned* frequencies_cl = 0; /*frequency of code length codes*/
+unsigned* bitlen_lld = 0; /*lit,len,dist code lengths (int bits), literally (without repeat codes).*/
+unsigned* bitlen_lld_e = 0; /*bitlen_lld encoded with repeat codes (this is a rudimentary run length compression)*/
+size_t datasize = dataend - datapos;
+/*
+If we could call "bitlen_cl" the the code length code lengths ("clcl"), that is the bit lengths of codes to represent
+tree_cl in CLCL_ORDER, then due to the huffman compression of huffman tree representations ("two levels"), there are
+some analogies:
+bitlen_lld is to tree_cl what data is to tree_ll and tree_d.
+bitlen_lld_e is to bitlen_lld what lz77_encoded is to data.
+bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded.
+*/
+unsigned BFINAL = final;
+size_t i;
+size_t numcodes_ll, numcodes_d, numcodes_lld, numcodes_lld_e, numcodes_cl;
+unsigned HLIT, HDIST, HCLEN;
+uivector_init(&lz77_encoded);
+HuffmanTree_init(&tree_ll);
+HuffmanTree_init(&tree_d);
+HuffmanTree_init(&tree_cl);
+/* could fit on stack, but >1KB is on the larger side so allocate instead */
+frequencies_ll = (unsigned*)lodepng_malloc(286 * sizeof(*frequencies_ll));
+frequencies_d = (unsigned*)lodepng_malloc(30 * sizeof(*frequencies_d));
+frequencies_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));
+if(!frequencies_ll || !frequencies_d || !frequencies_cl) error = 83; /*alloc fail*/
+/*This while loop never loops due to a break at the end, it is here to
+allow breaking out of it to the cleanup phase on error conditions.*/
+while(!error) {
+lodepng_memset(frequencies_ll, 0, 286 * sizeof(*frequencies_ll));
+lodepng_memset(frequencies_d, 0, 30 * sizeof(*frequencies_d));
+lodepng_memset(frequencies_cl, 0, NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));
+if(settings->use_lz77) {
+error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
+settings->minmatch, settings->nicematch, settings->lazymatching);
+if(error) break;
+} else {
+if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/);
+for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/
+}
+/*Count the frequencies of lit, len and dist codes*/
+for(i = 0; i != lz77_encoded.size; ++i) {
+unsigned symbol = lz77_encoded.data[i];
+++frequencies_ll[symbol];
+if(symbol > 256) {
+unsigned dist = lz77_encoded.data[i + 2];
+++frequencies_d[dist];
+i += 3;
+}
+}
+frequencies_ll[256] = 1; /*there will be exactly 1 end code, at the end of the block*/
+/*Make both huffman trees, one for the lit and len codes, one for the dist codes*/
+error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll, 257, 286, 15);
+if(error) break;
+/*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/
+error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d, 2, 30, 15);
+if(error) break;
+numcodes_ll = LODEPNG_MIN(tree_ll.numcodes, 286);
+numcodes_d = LODEPNG_MIN(tree_d.numcodes, 30);
+/*store the code lengths of both generated trees in bitlen_lld*/
+numcodes_lld = numcodes_ll + numcodes_d;
+bitlen_lld = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld));
+/*numcodes_lld_e never needs more size than bitlen_lld*/
+bitlen_lld_e = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld_e));
+if(!bitlen_lld || !bitlen_lld_e) ERROR_BREAK(83); /*alloc fail*/
+numcodes_lld_e = 0;
+for(i = 0; i != numcodes_ll; ++i) bitlen_lld[i] = tree_ll.lengths[i];
+for(i = 0; i != numcodes_d; ++i) bitlen_lld[numcodes_ll + i] = tree_d.lengths[i];
+/*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times),
+17 (3-10 zeroes), 18 (11-138 zeroes)*/
+for(i = 0; i != numcodes_lld; ++i) {
+unsigned j = 0; /*amount of repetitions*/
+while(i + j + 1 < numcodes_lld && bitlen_lld[i + j + 1] == bitlen_lld[i]) ++j;
+if(bitlen_lld[i] == 0 && j >= 2) /*repeat code for zeroes*/ {
+++j; /*include the first zero*/
+if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ {
+bitlen_lld_e[numcodes_lld_e++] = 17;
+bitlen_lld_e[numcodes_lld_e++] = j - 3;
+} else /*repeat code 18 supports max 138 zeroes*/ {
+if(j > 138) j = 138;
+bitlen_lld_e[numcodes_lld_e++] = 18;
+bitlen_lld_e[numcodes_lld_e++] = j - 11;
+}
+i += (j - 1);
+} else if(j >= 3) /*repeat code for value other than zero*/ {
+size_t k;
+unsigned num = j / 6u, rest = j % 6u;
+bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
+for(k = 0; k < num; ++k) {
+bitlen_lld_e[numcodes_lld_e++] = 16;
+bitlen_lld_e[numcodes_lld_e++] = 6 - 3;
+}
+if(rest >= 3) {
+bitlen_lld_e[numcodes_lld_e++] = 16;
+bitlen_lld_e[numcodes_lld_e++] = rest - 3;
+}
+else j -= rest;
+i += j;
+} else /*too short to benefit from repeat code*/ {
+bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
+}
+}
+/*generate tree_cl, the huffmantree of huffmantrees*/
+for(i = 0; i != numcodes_lld_e; ++i) {
+++frequencies_cl[bitlen_lld_e[i]];
+/*after a repeat code come the bits that specify the number of repetitions,
+those don't need to be in the frequencies_cl calculation*/
+if(bitlen_lld_e[i] >= 16) ++i;
+}
+error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl,
+NUM_CODE_LENGTH_CODES, NUM_CODE_LENGTH_CODES, 7);
+if(error) break;
+/*compute amount of code-length-code-lengths to output*/
+numcodes_cl = NUM_CODE_LENGTH_CODES;
+/*trim zeros at the end (using CLCL_ORDER), but minimum size must be 4 (see HCLEN below)*/
+while(numcodes_cl > 4u && tree_cl.lengths[CLCL_ORDER[numcodes_cl - 1u]] == 0) {
+numcodes_cl--;
+}
+/*
+Write everything into the output
+After the BFINAL and BTYPE, the dynamic block consists out of the following:
+- 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN
+- (HCLEN+4)*3 bits code lengths of code length alphabet
+- HLIT + 257 code lengths of lit/length alphabet (encoded using the code length
+alphabet, + possible repetition codes 16, 17, 18)
+- HDIST + 1 code lengths of distance alphabet (encoded using the code length
+alphabet, + possible repetition codes 16, 17, 18)
+- compressed data
+- 256 (end code)
+*/
+/*Write block type*/
+writeBits(writer, BFINAL, 1);
+writeBits(writer, 0, 1); /*first bit of BTYPE "dynamic"*/
+writeBits(writer, 1, 1); /*second bit of BTYPE "dynamic"*/
+/*write the HLIT, HDIST and HCLEN values*/
+/*all three sizes take trimmed ending zeroes into account, done either by HuffmanTree_makeFromFrequencies
+or in the loop for numcodes_cl above, which saves space. */
+HLIT = (unsigned)(numcodes_ll - 257);
+HDIST = (unsigned)(numcodes_d - 1);
+HCLEN = (unsigned)(numcodes_cl - 4);
+writeBits(writer, HLIT, 5);
+writeBits(writer, HDIST, 5);
+writeBits(writer, HCLEN, 4);
+/*write the code lengths of the code length alphabet ("bitlen_cl")*/
+for(i = 0; i != numcodes_cl; ++i) writeBits(writer, tree_cl.lengths[CLCL_ORDER[i]], 3);
+/*write the lengths of the lit/len AND the dist alphabet*/
+for(i = 0; i != numcodes_lld_e; ++i) {
+writeBitsReversed(writer, tree_cl.codes[bitlen_lld_e[i]], tree_cl.lengths[bitlen_lld_e[i]]);
+/*extra bits of repeat codes*/
+if(bitlen_lld_e[i] == 16) writeBits(writer, bitlen_lld_e[++i], 2);
+else if(bitlen_lld_e[i] == 17) writeBits(writer, bitlen_lld_e[++i], 3);
+else if(bitlen_lld_e[i] == 18) writeBits(writer, bitlen_lld_e[++i], 7);
+}
+/*write the compressed data symbols*/
+writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
+/*error: the length of the end code 256 must be larger than 0*/
+if(tree_ll.lengths[256] == 0) ERROR_BREAK(64);
+/*write the end code*/
+writeBitsReversed(writer, tree_ll.codes[256], tree_ll.lengths[256]);
+break; /*end of error-while*/
+}
+/*cleanup*/
+uivector_cleanup(&lz77_encoded);
+HuffmanTree_cleanup(&tree_ll);
+HuffmanTree_cleanup(&tree_d);
+HuffmanTree_cleanup(&tree_cl);
+lodepng_free(frequencies_ll);
+lodepng_free(frequencies_d);
+lodepng_free(frequencies_cl);
+lodepng_free(bitlen_lld);
+lodepng_free(bitlen_lld_e);
+return error;
+}
+static unsigned deflateFixed(LodePNGBitWriter* writer, Hash* hash,
+const unsigned char* data,
+size_t datapos, size_t dataend,
+const LodePNGCompressSettings* settings, unsigned final) {
+HuffmanTree tree_ll; /*tree for literal values and length codes*/
+HuffmanTree tree_d; /*tree for distance codes*/
+unsigned BFINAL = final;
+unsigned error = 0;
+size_t i;
+HuffmanTree_init(&tree_ll);
+HuffmanTree_init(&tree_d);
+error = generateFixedLitLenTree(&tree_ll);
+if(!error) error = generateFixedDistanceTree(&tree_d);
+if(!error) {
+writeBits(writer, BFINAL, 1);
+writeBits(writer, 1, 1); /*first bit of BTYPE*/
+writeBits(writer, 0, 1); /*second bit of BTYPE*/
+if(settings->use_lz77) /*LZ77 encoded*/ {
+uivector lz77_encoded;
+uivector_init(&lz77_encoded);
+error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
+settings->minmatch, settings->nicematch, settings->lazymatching);
+if(!error) writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
+uivector_cleanup(&lz77_encoded);
+} else /*no LZ77, but still will be Huffman compressed*/ {
+for(i = datapos; i < dataend; ++i) {
+writeBitsReversed(writer, tree_ll.codes[data[i]], tree_ll.lengths[data[i]]);
+}
+}
+/*add END code*/
+if(!error) writeBitsReversed(writer,tree_ll.codes[256], tree_ll.lengths[256]);
+}
+/*cleanup*/
+HuffmanTree_cleanup(&tree_ll);
+HuffmanTree_cleanup(&tree_d);
+return error;
+}
+static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize,
+const LodePNGCompressSettings* settings) {
+unsigned error = 0;
+size_t i, blocksize, numdeflateblocks;
+Hash hash;
+LodePNGBitWriter writer;
+LodePNGBitWriter_init(&writer, out);
+if(settings->btype > 2) return 61;
+else if(settings->btype == 0) return deflateNoCompression(out, in, insize);
+else if(settings->btype == 1) blocksize = insize;
+else /*if(settings->btype == 2)*/ {
+/*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/
+blocksize = insize / 8u + 8;
+if(blocksize < 65536) blocksize = 65536;
+if(blocksize > 262144) blocksize = 262144;
+}
+numdeflateblocks = (insize + blocksize - 1) / blocksize;
+if(numdeflateblocks == 0) numdeflateblocks = 1;
+error = hash_init(&hash, settings->windowsize);
+if(!error) {
+for(i = 0; i != numdeflateblocks && !error; ++i) {
+unsigned final = (i == numdeflateblocks - 1);
+size_t start = i * blocksize;
+size_t end = start + blocksize;
+if(end > insize) end = insize;
+if(settings->btype == 1) error = deflateFixed(&writer, &hash, in, start, end, settings, final);
+else if(settings->btype == 2) error = deflateDynamic(&writer, &hash, in, start, end, settings, final);
+}
+}
+hash_cleanup(&hash);
+return error;
+}
+unsigned lodepng_deflate(unsigned char** out, size_t* outsize,
+const unsigned char* in, size_t insize,
+const LodePNGCompressSettings* settings) {
+ucvector v = ucvector_init(*out, *outsize);
+unsigned error = lodepng_deflatev(&v, in, insize, settings);
+*out = v.data;
+*outsize = v.size;
+return error;
+}
+static unsigned deflate(unsigned char** out, size_t* outsize,
+const unsigned char* in, size_t insize,
+const LodePNGCompressSettings* settings) {
+if(settings->custom_deflate) {
+unsigned error = settings->custom_deflate(out, outsize, in, insize, settings);
+/*the custom deflate is allowed to have its own error codes, however, we translate it to code 111*/
+return error ? 111 : 0;
+} else {
+return lodepng_deflate(out, outsize, in, insize, settings);
+}
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Adler32                                                                / */
+/* ////////////////////////////////////////////////////////////////////////// */
+static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) {
+unsigned s1 = adler & 0xffffu;
+unsigned s2 = (adler >> 16u) & 0xffffu;
+while(len != 0u) {
+unsigned i;
+/*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/
+unsigned amount = len > 5552u ? 5552u : len;
+len -= amount;
+for(i = 0; i != amount; ++i) {
+s1 += (*data++);
+s2 += s1;
+}
+s1 %= 65521u;
+s2 %= 65521u;
+}
+return (s2 << 16u) | s1;
+}
+/*Return the adler32 of the bytes data[0..len-1]*/
+static unsigned adler32(const unsigned char* data, unsigned len) {
+return update_adler32(1u, data, len);
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Zlib                                                                   / */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_DECODER
+static unsigned lodepng_zlib_decompressv(ucvector* out,
+const unsigned char* in, size_t insize,
+const LodePNGDecompressSettings* settings) {
+unsigned error = 0;
+unsigned CM, CINFO, FDICT;
+if(insize < 2) return 53; /*error, size of zlib data too small*/
+/*read information from zlib header*/
+if((in[0] * 256 + in[1]) % 31 != 0) {
+/*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/
+return 24;
+}
+CM = in[0] & 15;
+CINFO = (in[0] >> 4) & 15;
+/*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/
+FDICT = (in[1] >> 5) & 1;
+/*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/
+if(CM != 8 || CINFO > 7) {
+/*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/
+return 25;
+}
+if(FDICT != 0) {
+/*error: the specification of PNG says about the zlib stream:
+"The additional flags shall not specify a preset dictionary."*/
+return 26;
+}
+error = inflatev(out, in + 2, insize - 2, settings);
+if(error) return error;
+if(!settings->ignore_adler32) {
+unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]);
+unsigned checksum = adler32(out->data, (unsigned)(out->size));
+if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/
+}
+return 0; /*no error*/
+}
+unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in,
+size_t insize, const LodePNGDecompressSettings* settings) {
+ucvector v = ucvector_init(*out, *outsize);
+unsigned error = lodepng_zlib_decompressv(&v, in, insize, settings);
+*out = v.data;
+*outsize = v.size;
+return error;
+}
+/*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */
+static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size,
+const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) {
+unsigned error;
+if(settings->custom_zlib) {
+error = settings->custom_zlib(out, outsize, in, insize, settings);
+if(error) {
+/*the custom zlib is allowed to have its own error codes, however, we translate it to code 110*/
+error = 110;
+/*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
+if(settings->max_output_size && *outsize > settings->max_output_size) error = 109;
+}
+} else {
+ucvector v = ucvector_init(*out, *outsize);
+if(expected_size) {
+/*reserve the memory to avoid intermediate reallocations*/
+ucvector_resize(&v, *outsize + expected_size);
+v.size = *outsize;
+}
+error = lodepng_zlib_decompressv(&v, in, insize, settings);
+*out = v.data;
+*outsize = v.size;
+}
+return error;
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+size_t insize, const LodePNGCompressSettings* settings) {
+size_t i;
+unsigned error;
+unsigned char* deflatedata = 0;
+size_t deflatesize = 0;
+error = deflate(&deflatedata, &deflatesize, in, insize, settings);
+*out = NULL;
+*outsize = 0;
+if(!error) {
+*outsize = deflatesize + 6;
+*out = (unsigned char*)lodepng_malloc(*outsize);
+if(!*out) error = 83; /*alloc fail*/
+}
+if(!error) {
+unsigned ADLER32 = adler32(in, (unsigned)insize);
+/*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/
+unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/
+unsigned FLEVEL = 0;
+unsigned FDICT = 0;
+unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64;
+unsigned FCHECK = 31 - CMFFLG % 31;
+CMFFLG += FCHECK;
+(*out)[0] = (unsigned char)(CMFFLG >> 8);
+(*out)[1] = (unsigned char)(CMFFLG & 255);
+for(i = 0; i != deflatesize; ++i) (*out)[i + 2] = deflatedata[i];
+lodepng_set32bitInt(&(*out)[*outsize - 4], ADLER32);
+}
+lodepng_free(deflatedata);
+return error;
+}
+/* compress using the default or custom zlib function */
+static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+size_t insize, const LodePNGCompressSettings* settings) {
+if(settings->custom_zlib) {
+unsigned error = settings->custom_zlib(out, outsize, in, insize, settings);
+/*the custom zlib is allowed to have its own error codes, however, we translate it to code 111*/
+return error ? 111 : 0;
+} else {
+return lodepng_zlib_compress(out, outsize, in, insize, settings);
+}
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#else /*no LODEPNG_COMPILE_ZLIB*/
+#ifdef LODEPNG_COMPILE_DECODER
+static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size,
+const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) {
+if(!settings->custom_zlib) return 87; /*no custom zlib function provided */
+(void)expected_size;
+return settings->custom_zlib(out, outsize, in, insize, settings);
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+size_t insize, const LodePNGCompressSettings* settings) {
+if(!settings->custom_zlib) return 87; /*no custom zlib function provided */
+return settings->custom_zlib(out, outsize, in, insize, settings);
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_ZLIB*/
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_ENCODER
+/*this is a good tradeoff between speed and compression ratio*/
+#define DEFAULT_WINDOWSIZE 2048
+void lodepng_compress_settings_init(LodePNGCompressSettings* settings) {
+/*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/
+settings->btype = 2;
+settings->use_lz77 = 1;
+settings->windowsize = DEFAULT_WINDOWSIZE;
+settings->minmatch = 3;
+settings->nicematch = 128;
+settings->lazymatching = 1;
+settings->custom_zlib = 0;
+settings->custom_deflate = 0;
+settings->custom_context = 0;
+}
+const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0};
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#ifdef LODEPNG_COMPILE_DECODER
+void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) {
+settings->ignore_adler32 = 0;
+settings->ignore_nlen = 0;
+settings->max_output_size = 0;
+settings->custom_zlib = 0;
+settings->custom_inflate = 0;
+settings->custom_context = 0;
+}
+const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0, 0, 0};
+#endif /*LODEPNG_COMPILE_DECODER*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // End of Zlib related code. Begin of PNG related code.                 // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_PNG
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / CRC32                                                                  / */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_CRC
+static const unsigned lodepng_crc32_table0[256] = {
+0x00000000u, 0x77073096u, 0xee0e612cu, 0x990951bau, 0x076dc419u, 0x706af48fu, 0xe963a535u, 0x9e6495a3u,
+0x0edb8832u, 0x79dcb8a4u, 0xe0d5e91eu, 0x97d2d988u, 0x09b64c2bu, 0x7eb17cbdu, 0xe7b82d07u, 0x90bf1d91u,
+0x1db71064u, 0x6ab020f2u, 0xf3b97148u, 0x84be41deu, 0x1adad47du, 0x6ddde4ebu, 0xf4d4b551u, 0x83d385c7u,
+0x136c9856u, 0x646ba8c0u, 0xfd62f97au, 0x8a65c9ecu, 0x14015c4fu, 0x63066cd9u, 0xfa0f3d63u, 0x8d080df5u,
+0x3b6e20c8u, 0x4c69105eu, 0xd56041e4u, 0xa2677172u, 0x3c03e4d1u, 0x4b04d447u, 0xd20d85fdu, 0xa50ab56bu,
+0x35b5a8fau, 0x42b2986cu, 0xdbbbc9d6u, 0xacbcf940u, 0x32d86ce3u, 0x45df5c75u, 0xdcd60dcfu, 0xabd13d59u,
+0x26d930acu, 0x51de003au, 0xc8d75180u, 0xbfd06116u, 0x21b4f4b5u, 0x56b3c423u, 0xcfba9599u, 0xb8bda50fu,
+0x2802b89eu, 0x5f058808u, 0xc60cd9b2u, 0xb10be924u, 0x2f6f7c87u, 0x58684c11u, 0xc1611dabu, 0xb6662d3du,
+0x76dc4190u, 0x01db7106u, 0x98d220bcu, 0xefd5102au, 0x71b18589u, 0x06b6b51fu, 0x9fbfe4a5u, 0xe8b8d433u,
+0x7807c9a2u, 0x0f00f934u, 0x9609a88eu, 0xe10e9818u, 0x7f6a0dbbu, 0x086d3d2du, 0x91646c97u, 0xe6635c01u,
+0x6b6b51f4u, 0x1c6c6162u, 0x856530d8u, 0xf262004eu, 0x6c0695edu, 0x1b01a57bu, 0x8208f4c1u, 0xf50fc457u,
+0x65b0d9c6u, 0x12b7e950u, 0x8bbeb8eau, 0xfcb9887cu, 0x62dd1ddfu, 0x15da2d49u, 0x8cd37cf3u, 0xfbd44c65u,
+0x4db26158u, 0x3ab551ceu, 0xa3bc0074u, 0xd4bb30e2u, 0x4adfa541u, 0x3dd895d7u, 0xa4d1c46du, 0xd3d6f4fbu,
+0x4369e96au, 0x346ed9fcu, 0xad678846u, 0xda60b8d0u, 0x44042d73u, 0x33031de5u, 0xaa0a4c5fu, 0xdd0d7cc9u,
+0x5005713cu, 0x270241aau, 0xbe0b1010u, 0xc90c2086u, 0x5768b525u, 0x206f85b3u, 0xb966d409u, 0xce61e49fu,
+0x5edef90eu, 0x29d9c998u, 0xb0d09822u, 0xc7d7a8b4u, 0x59b33d17u, 0x2eb40d81u, 0xb7bd5c3bu, 0xc0ba6cadu,
+0xedb88320u, 0x9abfb3b6u, 0x03b6e20cu, 0x74b1d29au, 0xead54739u, 0x9dd277afu, 0x04db2615u, 0x73dc1683u,
+0xe3630b12u, 0x94643b84u, 0x0d6d6a3eu, 0x7a6a5aa8u, 0xe40ecf0bu, 0x9309ff9du, 0x0a00ae27u, 0x7d079eb1u,
+0xf00f9344u, 0x8708a3d2u, 0x1e01f268u, 0x6906c2feu, 0xf762575du, 0x806567cbu, 0x196c3671u, 0x6e6b06e7u,
+0xfed41b76u, 0x89d32be0u, 0x10da7a5au, 0x67dd4accu, 0xf9b9df6fu, 0x8ebeeff9u, 0x17b7be43u, 0x60b08ed5u,
+0xd6d6a3e8u, 0xa1d1937eu, 0x38d8c2c4u, 0x4fdff252u, 0xd1bb67f1u, 0xa6bc5767u, 0x3fb506ddu, 0x48b2364bu,
+0xd80d2bdau, 0xaf0a1b4cu, 0x36034af6u, 0x41047a60u, 0xdf60efc3u, 0xa867df55u, 0x316e8eefu, 0x4669be79u,
+0xcb61b38cu, 0xbc66831au, 0x256fd2a0u, 0x5268e236u, 0xcc0c7795u, 0xbb0b4703u, 0x220216b9u, 0x5505262fu,
+0xc5ba3bbeu, 0xb2bd0b28u, 0x2bb45a92u, 0x5cb36a04u, 0xc2d7ffa7u, 0xb5d0cf31u, 0x2cd99e8bu, 0x5bdeae1du,
+0x9b64c2b0u, 0xec63f226u, 0x756aa39cu, 0x026d930au, 0x9c0906a9u, 0xeb0e363fu, 0x72076785u, 0x05005713u,
+0x95bf4a82u, 0xe2b87a14u, 0x7bb12baeu, 0x0cb61b38u, 0x92d28e9bu, 0xe5d5be0du, 0x7cdcefb7u, 0x0bdbdf21u,
+0x86d3d2d4u, 0xf1d4e242u, 0x68ddb3f8u, 0x1fda836eu, 0x81be16cdu, 0xf6b9265bu, 0x6fb077e1u, 0x18b74777u,
+0x88085ae6u, 0xff0f6a70u, 0x66063bcau, 0x11010b5cu, 0x8f659effu, 0xf862ae69u, 0x616bffd3u, 0x166ccf45u,
+0xa00ae278u, 0xd70dd2eeu, 0x4e048354u, 0x3903b3c2u, 0xa7672661u, 0xd06016f7u, 0x4969474du, 0x3e6e77dbu,
+0xaed16a4au, 0xd9d65adcu, 0x40df0b66u, 0x37d83bf0u, 0xa9bcae53u, 0xdebb9ec5u, 0x47b2cf7fu, 0x30b5ffe9u,
+0xbdbdf21cu, 0xcabac28au, 0x53b39330u, 0x24b4a3a6u, 0xbad03605u, 0xcdd70693u, 0x54de5729u, 0x23d967bfu,
+0xb3667a2eu, 0xc4614ab8u, 0x5d681b02u, 0x2a6f2b94u, 0xb40bbe37u, 0xc30c8ea1u, 0x5a05df1bu, 0x2d02ef8du
+};
+static const unsigned lodepng_crc32_table1[256] = {
+0x00000000u, 0x191b3141u, 0x32366282u, 0x2b2d53c3u, 0x646cc504u, 0x7d77f445u, 0x565aa786u, 0x4f4196c7u,
+0xc8d98a08u, 0xd1c2bb49u, 0xfaefe88au, 0xe3f4d9cbu, 0xacb54f0cu, 0xb5ae7e4du, 0x9e832d8eu, 0x87981ccfu,
+0x4ac21251u, 0x53d92310u, 0x78f470d3u, 0x61ef4192u, 0x2eaed755u, 0x37b5e614u, 0x1c98b5d7u, 0x05838496u,
+0x821b9859u, 0x9b00a918u, 0xb02dfadbu, 0xa936cb9au, 0xe6775d5du, 0xff6c6c1cu, 0xd4413fdfu, 0xcd5a0e9eu,
+0x958424a2u, 0x8c9f15e3u, 0xa7b24620u, 0xbea97761u, 0xf1e8e1a6u, 0xe8f3d0e7u, 0xc3de8324u, 0xdac5b265u,
+0x5d5daeaau, 0x44469febu, 0x6f6bcc28u, 0x7670fd69u, 0x39316baeu, 0x202a5aefu, 0x0b07092cu, 0x121c386du,
+0xdf4636f3u, 0xc65d07b2u, 0xed705471u, 0xf46b6530u, 0xbb2af3f7u, 0xa231c2b6u, 0x891c9175u, 0x9007a034u,
+0x179fbcfbu, 0x0e848dbau, 0x25a9de79u, 0x3cb2ef38u, 0x73f379ffu, 0x6ae848beu, 0x41c51b7du, 0x58de2a3cu,
+0xf0794f05u, 0xe9627e44u, 0xc24f2d87u, 0xdb541cc6u, 0x94158a01u, 0x8d0ebb40u, 0xa623e883u, 0xbf38d9c2u,
+0x38a0c50du, 0x21bbf44cu, 0x0a96a78fu, 0x138d96ceu, 0x5ccc0009u, 0x45d73148u, 0x6efa628bu, 0x77e153cau,
+0xbabb5d54u, 0xa3a06c15u, 0x888d3fd6u, 0x91960e97u, 0xded79850u, 0xc7cca911u, 0xece1fad2u, 0xf5facb93u,
+0x7262d75cu, 0x6b79e61du, 0x4054b5deu, 0x594f849fu, 0x160e1258u, 0x0f152319u, 0x243870dau, 0x3d23419bu,
+0x65fd6ba7u, 0x7ce65ae6u, 0x57cb0925u, 0x4ed03864u, 0x0191aea3u, 0x188a9fe2u, 0x33a7cc21u, 0x2abcfd60u,
+0xad24e1afu, 0xb43fd0eeu, 0x9f12832du, 0x8609b26cu, 0xc94824abu, 0xd05315eau, 0xfb7e4629u, 0xe2657768u,
+0x2f3f79f6u, 0x362448b7u, 0x1d091b74u, 0x04122a35u, 0x4b53bcf2u, 0x52488db3u, 0x7965de70u, 0x607eef31u,
+0xe7e6f3feu, 0xfefdc2bfu, 0xd5d0917cu, 0xcccba03du, 0x838a36fau, 0x9a9107bbu, 0xb1bc5478u, 0xa8a76539u,
+0x3b83984bu, 0x2298a90au, 0x09b5fac9u, 0x10aecb88u, 0x5fef5d4fu, 0x46f46c0eu, 0x6dd93fcdu, 0x74c20e8cu,
+0xf35a1243u, 0xea412302u, 0xc16c70c1u, 0xd8774180u, 0x9736d747u, 0x8e2de606u, 0xa500b5c5u, 0xbc1b8484u,
+0x71418a1au, 0x685abb5bu, 0x4377e898u, 0x5a6cd9d9u, 0x152d4f1eu, 0x0c367e5fu, 0x271b2d9cu, 0x3e001cddu,
+0xb9980012u, 0xa0833153u, 0x8bae6290u, 0x92b553d1u, 0xddf4c516u, 0xc4eff457u, 0xefc2a794u, 0xf6d996d5u,
+0xae07bce9u, 0xb71c8da8u, 0x9c31de6bu, 0x852aef2au, 0xca6b79edu, 0xd37048acu, 0xf85d1b6fu, 0xe1462a2eu,
+0x66de36e1u, 0x7fc507a0u, 0x54e85463u, 0x4df36522u, 0x02b2f3e5u, 0x1ba9c2a4u, 0x30849167u, 0x299fa026u,
+0xe4c5aeb8u, 0xfdde9ff9u, 0xd6f3cc3au, 0xcfe8fd7bu, 0x80a96bbcu, 0x99b25afdu, 0xb29f093eu, 0xab84387fu,
+0x2c1c24b0u, 0x350715f1u, 0x1e2a4632u, 0x07317773u, 0x4870e1b4u, 0x516bd0f5u, 0x7a468336u, 0x635db277u,
+0xcbfad74eu, 0xd2e1e60fu, 0xf9ccb5ccu, 0xe0d7848du, 0xaf96124au, 0xb68d230bu, 0x9da070c8u, 0x84bb4189u,
+0x03235d46u, 0x1a386c07u, 0x31153fc4u, 0x280e0e85u, 0x674f9842u, 0x7e54a903u, 0x5579fac0u, 0x4c62cb81u,
+0x8138c51fu, 0x9823f45eu, 0xb30ea79du, 0xaa1596dcu, 0xe554001bu, 0xfc4f315au, 0xd7626299u, 0xce7953d8u,
+0x49e14f17u, 0x50fa7e56u, 0x7bd72d95u, 0x62cc1cd4u, 0x2d8d8a13u, 0x3496bb52u, 0x1fbbe891u, 0x06a0d9d0u,
+0x5e7ef3ecu, 0x4765c2adu, 0x6c48916eu, 0x7553a02fu, 0x3a1236e8u, 0x230907a9u, 0x0824546au, 0x113f652bu,
+0x96a779e4u, 0x8fbc48a5u, 0xa4911b66u, 0xbd8a2a27u, 0xf2cbbce0u, 0xebd08da1u, 0xc0fdde62u, 0xd9e6ef23u,
+0x14bce1bdu, 0x0da7d0fcu, 0x268a833fu, 0x3f91b27eu, 0x70d024b9u, 0x69cb15f8u, 0x42e6463bu, 0x5bfd777au,
+0xdc656bb5u, 0xc57e5af4u, 0xee530937u, 0xf7483876u, 0xb809aeb1u, 0xa1129ff0u, 0x8a3fcc33u, 0x9324fd72u
+};
+static const unsigned lodepng_crc32_table2[256] = {
+0x00000000u, 0x01c26a37u, 0x0384d46eu, 0x0246be59u, 0x0709a8dcu, 0x06cbc2ebu, 0x048d7cb2u, 0x054f1685u,
+0x0e1351b8u, 0x0fd13b8fu, 0x0d9785d6u, 0x0c55efe1u, 0x091af964u, 0x08d89353u, 0x0a9e2d0au, 0x0b5c473du,
+0x1c26a370u, 0x1de4c947u, 0x1fa2771eu, 0x1e601d29u, 0x1b2f0bacu, 0x1aed619bu, 0x18abdfc2u, 0x1969b5f5u,
+0x1235f2c8u, 0x13f798ffu, 0x11b126a6u, 0x10734c91u, 0x153c5a14u, 0x14fe3023u, 0x16b88e7au, 0x177ae44du,
+0x384d46e0u, 0x398f2cd7u, 0x3bc9928eu, 0x3a0bf8b9u, 0x3f44ee3cu, 0x3e86840bu, 0x3cc03a52u, 0x3d025065u,
+0x365e1758u, 0x379c7d6fu, 0x35dac336u, 0x3418a901u, 0x3157bf84u, 0x3095d5b3u, 0x32d36beau, 0x331101ddu,
+0x246be590u, 0x25a98fa7u, 0x27ef31feu, 0x262d5bc9u, 0x23624d4cu, 0x22a0277bu, 0x20e69922u, 0x2124f315u,
+0x2a78b428u, 0x2bbade1fu, 0x29fc6046u, 0x283e0a71u, 0x2d711cf4u, 0x2cb376c3u, 0x2ef5c89au, 0x2f37a2adu,
+0x709a8dc0u, 0x7158e7f7u, 0x731e59aeu, 0x72dc3399u, 0x7793251cu, 0x76514f2bu, 0x7417f172u, 0x75d59b45u,
+0x7e89dc78u, 0x7f4bb64fu, 0x7d0d0816u, 0x7ccf6221u, 0x798074a4u, 0x78421e93u, 0x7a04a0cau, 0x7bc6cafdu,
+0x6cbc2eb0u, 0x6d7e4487u, 0x6f38fadeu, 0x6efa90e9u, 0x6bb5866cu, 0x6a77ec5bu, 0x68315202u, 0x69f33835u,
+0x62af7f08u, 0x636d153fu, 0x612bab66u, 0x60e9c151u, 0x65a6d7d4u, 0x6464bde3u, 0x662203bau, 0x67e0698du,
+0x48d7cb20u, 0x4915a117u, 0x4b531f4eu, 0x4a917579u, 0x4fde63fcu, 0x4e1c09cbu, 0x4c5ab792u, 0x4d98dda5u,
+0x46c49a98u, 0x4706f0afu, 0x45404ef6u, 0x448224c1u, 0x41cd3244u, 0x400f5873u, 0x4249e62au, 0x438b8c1du,
+0x54f16850u, 0x55330267u, 0x5775bc3eu, 0x56b7d609u, 0x53f8c08cu, 0x523aaabbu, 0x507c14e2u, 0x51be7ed5u,
+0x5ae239e8u, 0x5b2053dfu, 0x5966ed86u, 0x58a487b1u, 0x5deb9134u, 0x5c29fb03u, 0x5e6f455au, 0x5fad2f6du,
+0xe1351b80u, 0xe0f771b7u, 0xe2b1cfeeu, 0xe373a5d9u, 0xe63cb35cu, 0xe7fed96bu, 0xe5b86732u, 0xe47a0d05u,
+0xef264a38u, 0xeee4200fu, 0xeca29e56u, 0xed60f461u, 0xe82fe2e4u, 0xe9ed88d3u, 0xebab368au, 0xea695cbdu,
+0xfd13b8f0u, 0xfcd1d2c7u, 0xfe976c9eu, 0xff5506a9u, 0xfa1a102cu, 0xfbd87a1bu, 0xf99ec442u, 0xf85cae75u,
+0xf300e948u, 0xf2c2837fu, 0xf0843d26u, 0xf1465711u, 0xf4094194u, 0xf5cb2ba3u, 0xf78d95fau, 0xf64fffcdu,
+0xd9785d60u, 0xd8ba3757u, 0xdafc890eu, 0xdb3ee339u, 0xde71f5bcu, 0xdfb39f8bu, 0xddf521d2u, 0xdc374be5u,
+0xd76b0cd8u, 0xd6a966efu, 0xd4efd8b6u, 0xd52db281u, 0xd062a404u, 0xd1a0ce33u, 0xd3e6706au, 0xd2241a5du,
+0xc55efe10u, 0xc49c9427u, 0xc6da2a7eu, 0xc7184049u, 0xc25756ccu, 0xc3953cfbu, 0xc1d382a2u, 0xc011e895u,
+0xcb4dafa8u, 0xca8fc59fu, 0xc8c97bc6u, 0xc90b11f1u, 0xcc440774u, 0xcd866d43u, 0xcfc0d31au, 0xce02b92du,
+0x91af9640u, 0x906dfc77u, 0x922b422eu, 0x93e92819u, 0x96a63e9cu, 0x976454abu, 0x9522eaf2u, 0x94e080c5u,
+0x9fbcc7f8u, 0x9e7eadcfu, 0x9c381396u, 0x9dfa79a1u, 0x98b56f24u, 0x99770513u, 0x9b31bb4au, 0x9af3d17du,
+0x8d893530u, 0x8c4b5f07u, 0x8e0de15eu, 0x8fcf8b69u, 0x8a809decu, 0x8b42f7dbu, 0x89044982u, 0x88c623b5u,
+0x839a6488u, 0x82580ebfu, 0x801eb0e6u, 0x81dcdad1u, 0x8493cc54u, 0x8551a663u, 0x8717183au, 0x86d5720du,
+0xa9e2d0a0u, 0xa820ba97u, 0xaa6604ceu, 0xaba46ef9u, 0xaeeb787cu, 0xaf29124bu, 0xad6fac12u, 0xacadc625u,
+0xa7f18118u, 0xa633eb2fu, 0xa4755576u, 0xa5b73f41u, 0xa0f829c4u, 0xa13a43f3u, 0xa37cfdaau, 0xa2be979du,
+0xb5c473d0u, 0xb40619e7u, 0xb640a7beu, 0xb782cd89u, 0xb2cddb0cu, 0xb30fb13bu, 0xb1490f62u, 0xb08b6555u,
+0xbbd72268u, 0xba15485fu, 0xb853f606u, 0xb9919c31u, 0xbcde8ab4u, 0xbd1ce083u, 0xbf5a5edau, 0xbe9834edu
+};
+static const unsigned lodepng_crc32_table3[256] = {
+0x00000000u, 0xb8bc6765u, 0xaa09c88bu, 0x12b5afeeu, 0x8f629757u, 0x37def032u, 0x256b5fdcu, 0x9dd738b9u,
+0xc5b428efu, 0x7d084f8au, 0x6fbde064u, 0xd7018701u, 0x4ad6bfb8u, 0xf26ad8ddu, 0xe0df7733u, 0x58631056u,
+0x5019579fu, 0xe8a530fau, 0xfa109f14u, 0x42acf871u, 0xdf7bc0c8u, 0x67c7a7adu, 0x75720843u, 0xcdce6f26u,
+0x95ad7f70u, 0x2d111815u, 0x3fa4b7fbu, 0x8718d09eu, 0x1acfe827u, 0xa2738f42u, 0xb0c620acu, 0x087a47c9u,
+0xa032af3eu, 0x188ec85bu, 0x0a3b67b5u, 0xb28700d0u, 0x2f503869u, 0x97ec5f0cu, 0x8559f0e2u, 0x3de59787u,
+0x658687d1u, 0xdd3ae0b4u, 0xcf8f4f5au, 0x7733283fu, 0xeae41086u, 0x525877e3u, 0x40edd80du, 0xf851bf68u,
+0xf02bf8a1u, 0x48979fc4u, 0x5a22302au, 0xe29e574fu, 0x7f496ff6u, 0xc7f50893u, 0xd540a77du, 0x6dfcc018u,
+0x359fd04eu, 0x8d23b72bu, 0x9f9618c5u, 0x272a7fa0u, 0xbafd4719u, 0x0241207cu, 0x10f48f92u, 0xa848e8f7u,
+0x9b14583du, 0x23a83f58u, 0x311d90b6u, 0x89a1f7d3u, 0x1476cf6au, 0xaccaa80fu, 0xbe7f07e1u, 0x06c36084u,
+0x5ea070d2u, 0xe61c17b7u, 0xf4a9b859u, 0x4c15df3cu, 0xd1c2e785u, 0x697e80e0u, 0x7bcb2f0eu, 0xc377486bu,
+0xcb0d0fa2u, 0x73b168c7u, 0x6104c729u, 0xd9b8a04cu, 0x446f98f5u, 0xfcd3ff90u, 0xee66507eu, 0x56da371bu,
+0x0eb9274du, 0xb6054028u, 0xa4b0efc6u, 0x1c0c88a3u, 0x81dbb01au, 0x3967d77fu, 0x2bd27891u, 0x936e1ff4u,
+0x3b26f703u, 0x839a9066u, 0x912f3f88u, 0x299358edu, 0xb4446054u, 0x0cf80731u, 0x1e4da8dfu, 0xa6f1cfbau,
+0xfe92dfecu, 0x462eb889u, 0x549b1767u, 0xec277002u, 0x71f048bbu, 0xc94c2fdeu, 0xdbf98030u, 0x6345e755u,
+0x6b3fa09cu, 0xd383c7f9u, 0xc1366817u, 0x798a0f72u, 0xe45d37cbu, 0x5ce150aeu, 0x4e54ff40u, 0xf6e89825u,
+0xae8b8873u, 0x1637ef16u, 0x048240f8u, 0xbc3e279du, 0x21e91f24u, 0x99557841u, 0x8be0d7afu, 0x335cb0cau,
+0xed59b63bu, 0x55e5d15eu, 0x47507eb0u, 0xffec19d5u, 0x623b216cu, 0xda874609u, 0xc832e9e7u, 0x708e8e82u,
+0x28ed9ed4u, 0x9051f9b1u, 0x82e4565fu, 0x3a58313au, 0xa78f0983u, 0x1f336ee6u, 0x0d86c108u, 0xb53aa66du,
+0xbd40e1a4u, 0x05fc86c1u, 0x1749292fu, 0xaff54e4au, 0x322276f3u, 0x8a9e1196u, 0x982bbe78u, 0x2097d91du,
+0x78f4c94bu, 0xc048ae2eu, 0xd2fd01c0u, 0x6a4166a5u, 0xf7965e1cu, 0x4f2a3979u, 0x5d9f9697u, 0xe523f1f2u,
+0x4d6b1905u, 0xf5d77e60u, 0xe762d18eu, 0x5fdeb6ebu, 0xc2098e52u, 0x7ab5e937u, 0x680046d9u, 0xd0bc21bcu,
+0x88df31eau, 0x3063568fu, 0x22d6f961u, 0x9a6a9e04u, 0x07bda6bdu, 0xbf01c1d8u, 0xadb46e36u, 0x15080953u,
+0x1d724e9au, 0xa5ce29ffu, 0xb77b8611u, 0x0fc7e174u, 0x9210d9cdu, 0x2aacbea8u, 0x38191146u, 0x80a57623u,
+0xd8c66675u, 0x607a0110u, 0x72cfaefeu, 0xca73c99bu, 0x57a4f122u, 0xef189647u, 0xfdad39a9u, 0x45115eccu,
+0x764dee06u, 0xcef18963u, 0xdc44268du, 0x64f841e8u, 0xf92f7951u, 0x41931e34u, 0x5326b1dau, 0xeb9ad6bfu,
+0xb3f9c6e9u, 0x0b45a18cu, 0x19f00e62u, 0xa14c6907u, 0x3c9b51beu, 0x842736dbu, 0x96929935u, 0x2e2efe50u,
+0x2654b999u, 0x9ee8defcu, 0x8c5d7112u, 0x34e11677u, 0xa9362eceu, 0x118a49abu, 0x033fe645u, 0xbb838120u,
+0xe3e09176u, 0x5b5cf613u, 0x49e959fdu, 0xf1553e98u, 0x6c820621u, 0xd43e6144u, 0xc68bceaau, 0x7e37a9cfu,
+0xd67f4138u, 0x6ec3265du, 0x7c7689b3u, 0xc4caeed6u, 0x591dd66fu, 0xe1a1b10au, 0xf3141ee4u, 0x4ba87981u,
+0x13cb69d7u, 0xab770eb2u, 0xb9c2a15cu, 0x017ec639u, 0x9ca9fe80u, 0x241599e5u, 0x36a0360bu, 0x8e1c516eu,
+0x866616a7u, 0x3eda71c2u, 0x2c6fde2cu, 0x94d3b949u, 0x090481f0u, 0xb1b8e695u, 0xa30d497bu, 0x1bb12e1eu,
+0x43d23e48u, 0xfb6e592du, 0xe9dbf6c3u, 0x516791a6u, 0xccb0a91fu, 0x740cce7au, 0x66b96194u, 0xde0506f1u
+};
+static const unsigned lodepng_crc32_table4[256] = {
+0x00000000u, 0x3d6029b0u, 0x7ac05360u, 0x47a07ad0u, 0xf580a6c0u, 0xc8e08f70u, 0x8f40f5a0u, 0xb220dc10u,
+0x30704bc1u, 0x0d106271u, 0x4ab018a1u, 0x77d03111u, 0xc5f0ed01u, 0xf890c4b1u, 0xbf30be61u, 0x825097d1u,
+0x60e09782u, 0x5d80be32u, 0x1a20c4e2u, 0x2740ed52u, 0x95603142u, 0xa80018f2u, 0xefa06222u, 0xd2c04b92u,
+0x5090dc43u, 0x6df0f5f3u, 0x2a508f23u, 0x1730a693u, 0xa5107a83u, 0x98705333u, 0xdfd029e3u, 0xe2b00053u,
+0xc1c12f04u, 0xfca106b4u, 0xbb017c64u, 0x866155d4u, 0x344189c4u, 0x0921a074u, 0x4e81daa4u, 0x73e1f314u,
+0xf1b164c5u, 0xccd14d75u, 0x8b7137a5u, 0xb6111e15u, 0x0431c205u, 0x3951ebb5u, 0x7ef19165u, 0x4391b8d5u,
+0xa121b886u, 0x9c419136u, 0xdbe1ebe6u, 0xe681c256u, 0x54a11e46u, 0x69c137f6u, 0x2e614d26u, 0x13016496u,
+0x9151f347u, 0xac31daf7u, 0xeb91a027u, 0xd6f18997u, 0x64d15587u, 0x59b17c37u, 0x1e1106e7u, 0x23712f57u,
+0x58f35849u, 0x659371f9u, 0x22330b29u, 0x1f532299u, 0xad73fe89u, 0x9013d739u, 0xd7b3ade9u, 0xead38459u,
+0x68831388u, 0x55e33a38u, 0x124340e8u, 0x2f236958u, 0x9d03b548u, 0xa0639cf8u, 0xe7c3e628u, 0xdaa3cf98u,
+0x3813cfcbu, 0x0573e67bu, 0x42d39cabu, 0x7fb3b51bu, 0xcd93690bu, 0xf0f340bbu, 0xb7533a6bu, 0x8a3313dbu,
+0x0863840au, 0x3503adbau, 0x72a3d76au, 0x4fc3fedau, 0xfde322cau, 0xc0830b7au, 0x872371aau, 0xba43581au,
+0x9932774du, 0xa4525efdu, 0xe3f2242du, 0xde920d9du, 0x6cb2d18du, 0x51d2f83du, 0x167282edu, 0x2b12ab5du,
+0xa9423c8cu, 0x9422153cu, 0xd3826fecu, 0xeee2465cu, 0x5cc29a4cu, 0x61a2b3fcu, 0x2602c92cu, 0x1b62e09cu,
+0xf9d2e0cfu, 0xc4b2c97fu, 0x8312b3afu, 0xbe729a1fu, 0x0c52460fu, 0x31326fbfu, 0x7692156fu, 0x4bf23cdfu,
+0xc9a2ab0eu, 0xf4c282beu, 0xb362f86eu, 0x8e02d1deu, 0x3c220dceu, 0x0142247eu, 0x46e25eaeu, 0x7b82771eu,
+0xb1e6b092u, 0x8c869922u, 0xcb26e3f2u, 0xf646ca42u, 0x44661652u, 0x79063fe2u, 0x3ea64532u, 0x03c66c82u,
+0x8196fb53u, 0xbcf6d2e3u, 0xfb56a833u, 0xc6368183u, 0x74165d93u, 0x49767423u, 0x0ed60ef3u, 0x33b62743u,
+0xd1062710u, 0xec660ea0u, 0xabc67470u, 0x96a65dc0u, 0x248681d0u, 0x19e6a860u, 0x5e46d2b0u, 0x6326fb00u,
+0xe1766cd1u, 0xdc164561u, 0x9bb63fb1u, 0xa6d61601u, 0x14f6ca11u, 0x2996e3a1u, 0x6e369971u, 0x5356b0c1u,
+0x70279f96u, 0x4d47b626u, 0x0ae7ccf6u, 0x3787e546u, 0x85a73956u, 0xb8c710e6u, 0xff676a36u, 0xc2074386u,
+0x4057d457u, 0x7d37fde7u, 0x3a978737u, 0x07f7ae87u, 0xb5d77297u, 0x88b75b27u, 0xcf1721f7u, 0xf2770847u,
+0x10c70814u, 0x2da721a4u, 0x6a075b74u, 0x576772c4u, 0xe547aed4u, 0xd8278764u, 0x9f87fdb4u, 0xa2e7d404u,
+0x20b743d5u, 0x1dd76a65u, 0x5a7710b5u, 0x67173905u, 0xd537e515u, 0xe857cca5u, 0xaff7b675u, 0x92979fc5u,
+0xe915e8dbu, 0xd475c16bu, 0x93d5bbbbu, 0xaeb5920bu, 0x1c954e1bu, 0x21f567abu, 0x66551d7bu, 0x5b3534cbu,
+0xd965a31au, 0xe4058aaau, 0xa3a5f07au, 0x9ec5d9cau, 0x2ce505dau, 0x11852c6au, 0x562556bau, 0x6b457f0au,
+0x89f57f59u, 0xb49556e9u, 0xf3352c39u, 0xce550589u, 0x7c75d999u, 0x4115f029u, 0x06b58af9u, 0x3bd5a349u,
+0xb9853498u, 0x84e51d28u, 0xc34567f8u, 0xfe254e48u, 0x4c059258u, 0x7165bbe8u, 0x36c5c138u, 0x0ba5e888u,
+0x28d4c7dfu, 0x15b4ee6fu, 0x521494bfu, 0x6f74bd0fu, 0xdd54611fu, 0xe03448afu, 0xa794327fu, 0x9af41bcfu,
+0x18a48c1eu, 0x25c4a5aeu, 0x6264df7eu, 0x5f04f6ceu, 0xed242adeu, 0xd044036eu, 0x97e479beu, 0xaa84500eu,
+0x4834505du, 0x755479edu, 0x32f4033du, 0x0f942a8du, 0xbdb4f69du, 0x80d4df2du, 0xc774a5fdu, 0xfa148c4du,
+0x78441b9cu, 0x4524322cu, 0x028448fcu, 0x3fe4614cu, 0x8dc4bd5cu, 0xb0a494ecu, 0xf704ee3cu, 0xca64c78cu
+};
+static const unsigned lodepng_crc32_table5[256] = {
+0x00000000u, 0xcb5cd3a5u, 0x4dc8a10bu, 0x869472aeu, 0x9b914216u, 0x50cd91b3u, 0xd659e31du, 0x1d0530b8u,
+0xec53826du, 0x270f51c8u, 0xa19b2366u, 0x6ac7f0c3u, 0x77c2c07bu, 0xbc9e13deu, 0x3a0a6170u, 0xf156b2d5u,
+0x03d6029bu, 0xc88ad13eu, 0x4e1ea390u, 0x85427035u, 0x9847408du, 0x531b9328u, 0xd58fe186u, 0x1ed33223u,
+0xef8580f6u, 0x24d95353u, 0xa24d21fdu, 0x6911f258u, 0x7414c2e0u, 0xbf481145u, 0x39dc63ebu, 0xf280b04eu,
+0x07ac0536u, 0xccf0d693u, 0x4a64a43du, 0x81387798u, 0x9c3d4720u, 0x57619485u, 0xd1f5e62bu, 0x1aa9358eu,
+0xebff875bu, 0x20a354feu, 0xa6372650u, 0x6d6bf5f5u, 0x706ec54du, 0xbb3216e8u, 0x3da66446u, 0xf6fab7e3u,
+0x047a07adu, 0xcf26d408u, 0x49b2a6a6u, 0x82ee7503u, 0x9feb45bbu, 0x54b7961eu, 0xd223e4b0u, 0x197f3715u,
+0xe82985c0u, 0x23755665u, 0xa5e124cbu, 0x6ebdf76eu, 0x73b8c7d6u, 0xb8e41473u, 0x3e7066ddu, 0xf52cb578u,
+0x0f580a6cu, 0xc404d9c9u, 0x4290ab67u, 0x89cc78c2u, 0x94c9487au, 0x5f959bdfu, 0xd901e971u, 0x125d3ad4u,
+0xe30b8801u, 0x28575ba4u, 0xaec3290au, 0x659ffaafu, 0x789aca17u, 0xb3c619b2u, 0x35526b1cu, 0xfe0eb8b9u,
+0x0c8e08f7u, 0xc7d2db52u, 0x4146a9fcu, 0x8a1a7a59u, 0x971f4ae1u, 0x5c439944u, 0xdad7ebeau, 0x118b384fu,
+0xe0dd8a9au, 0x2b81593fu, 0xad152b91u, 0x6649f834u, 0x7b4cc88cu, 0xb0101b29u, 0x36846987u, 0xfdd8ba22u,
+0x08f40f5au, 0xc3a8dcffu, 0x453cae51u, 0x8e607df4u, 0x93654d4cu, 0x58399ee9u, 0xdeadec47u, 0x15f13fe2u,
+0xe4a78d37u, 0x2ffb5e92u, 0xa96f2c3cu, 0x6233ff99u, 0x7f36cf21u, 0xb46a1c84u, 0x32fe6e2au, 0xf9a2bd8fu,
+0x0b220dc1u, 0xc07ede64u, 0x46eaaccau, 0x8db67f6fu, 0x90b34fd7u, 0x5bef9c72u, 0xdd7beedcu, 0x16273d79u,
+0xe7718facu, 0x2c2d5c09u, 0xaab92ea7u, 0x61e5fd02u, 0x7ce0cdbau, 0xb7bc1e1fu, 0x31286cb1u, 0xfa74bf14u,
+0x1eb014d8u, 0xd5ecc77du, 0x5378b5d3u, 0x98246676u, 0x852156ceu, 0x4e7d856bu, 0xc8e9f7c5u, 0x03b52460u,
+0xf2e396b5u, 0x39bf4510u, 0xbf2b37beu, 0x7477e41bu, 0x6972d4a3u, 0xa22e0706u, 0x24ba75a8u, 0xefe6a60du,
+0x1d661643u, 0xd63ac5e6u, 0x50aeb748u, 0x9bf264edu, 0x86f75455u, 0x4dab87f0u, 0xcb3ff55eu, 0x006326fbu,
+0xf135942eu, 0x3a69478bu, 0xbcfd3525u, 0x77a1e680u, 0x6aa4d638u, 0xa1f8059du, 0x276c7733u, 0xec30a496u,
+0x191c11eeu, 0xd240c24bu, 0x54d4b0e5u, 0x9f886340u, 0x828d53f8u, 0x49d1805du, 0xcf45f2f3u, 0x04192156u,
+0xf54f9383u, 0x3e134026u, 0xb8873288u, 0x73dbe12du, 0x6eded195u, 0xa5820230u, 0x2316709eu, 0xe84aa33bu,
+0x1aca1375u, 0xd196c0d0u, 0x5702b27eu, 0x9c5e61dbu, 0x815b5163u, 0x4a0782c6u, 0xcc93f068u, 0x07cf23cdu,
+0xf6999118u, 0x3dc542bdu, 0xbb513013u, 0x700de3b6u, 0x6d08d30eu, 0xa65400abu, 0x20c07205u, 0xeb9ca1a0u,
+0x11e81eb4u, 0xdab4cd11u, 0x5c20bfbfu, 0x977c6c1au, 0x8a795ca2u, 0x41258f07u, 0xc7b1fda9u, 0x0ced2e0cu,
+0xfdbb9cd9u, 0x36e74f7cu, 0xb0733dd2u, 0x7b2fee77u, 0x662adecfu, 0xad760d6au, 0x2be27fc4u, 0xe0beac61u,
+0x123e1c2fu, 0xd962cf8au, 0x5ff6bd24u, 0x94aa6e81u, 0x89af5e39u, 0x42f38d9cu, 0xc467ff32u, 0x0f3b2c97u,
+0xfe6d9e42u, 0x35314de7u, 0xb3a53f49u, 0x78f9ececu, 0x65fcdc54u, 0xaea00ff1u, 0x28347d5fu, 0xe368aefau,
+0x16441b82u, 0xdd18c827u, 0x5b8cba89u, 0x90d0692cu, 0x8dd55994u, 0x46898a31u, 0xc01df89fu, 0x0b412b3au,
+0xfa1799efu, 0x314b4a4au, 0xb7df38e4u, 0x7c83eb41u, 0x6186dbf9u, 0xaada085cu, 0x2c4e7af2u, 0xe712a957u,
+0x15921919u, 0xdececabcu, 0x585ab812u, 0x93066bb7u, 0x8e035b0fu, 0x455f88aau, 0xc3cbfa04u, 0x089729a1u,
+0xf9c19b74u, 0x329d48d1u, 0xb4093a7fu, 0x7f55e9dau, 0x6250d962u, 0xa90c0ac7u, 0x2f987869u, 0xe4c4abccu
+};
+static const unsigned lodepng_crc32_table6[256] = {
+0x00000000u, 0xa6770bb4u, 0x979f1129u, 0x31e81a9du, 0xf44f2413u, 0x52382fa7u, 0x63d0353au, 0xc5a73e8eu,
+0x33ef4e67u, 0x959845d3u, 0xa4705f4eu, 0x020754fau, 0xc7a06a74u, 0x61d761c0u, 0x503f7b5du, 0xf64870e9u,
+0x67de9cceu, 0xc1a9977au, 0xf0418de7u, 0x56368653u, 0x9391b8ddu, 0x35e6b369u, 0x040ea9f4u, 0xa279a240u,
+0x5431d2a9u, 0xf246d91du, 0xc3aec380u, 0x65d9c834u, 0xa07ef6bau, 0x0609fd0eu, 0x37e1e793u, 0x9196ec27u,
+0xcfbd399cu, 0x69ca3228u, 0x582228b5u, 0xfe552301u, 0x3bf21d8fu, 0x9d85163bu, 0xac6d0ca6u, 0x0a1a0712u,
+0xfc5277fbu, 0x5a257c4fu, 0x6bcd66d2u, 0xcdba6d66u, 0x081d53e8u, 0xae6a585cu, 0x9f8242c1u, 0x39f54975u,
+0xa863a552u, 0x0e14aee6u, 0x3ffcb47bu, 0x998bbfcfu, 0x5c2c8141u, 0xfa5b8af5u, 0xcbb39068u, 0x6dc49bdcu,
+0x9b8ceb35u, 0x3dfbe081u, 0x0c13fa1cu, 0xaa64f1a8u, 0x6fc3cf26u, 0xc9b4c492u, 0xf85cde0fu, 0x5e2bd5bbu,
+0x440b7579u, 0xe27c7ecdu, 0xd3946450u, 0x75e36fe4u, 0xb044516au, 0x16335adeu, 0x27db4043u, 0x81ac4bf7u,
+0x77e43b1eu, 0xd19330aau, 0xe07b2a37u, 0x460c2183u, 0x83ab1f0du, 0x25dc14b9u, 0x14340e24u, 0xb2430590u,
+0x23d5e9b7u, 0x85a2e203u, 0xb44af89eu, 0x123df32au, 0xd79acda4u, 0x71edc610u, 0x4005dc8du, 0xe672d739u,
+0x103aa7d0u, 0xb64dac64u, 0x87a5b6f9u, 0x21d2bd4du, 0xe47583c3u, 0x42028877u, 0x73ea92eau, 0xd59d995eu,
+0x8bb64ce5u, 0x2dc14751u, 0x1c295dccu, 0xba5e5678u, 0x7ff968f6u, 0xd98e6342u, 0xe86679dfu, 0x4e11726bu,
+0xb8590282u, 0x1e2e0936u, 0x2fc613abu, 0x89b1181fu, 0x4c162691u, 0xea612d25u, 0xdb8937b8u, 0x7dfe3c0cu,
+0xec68d02bu, 0x4a1fdb9fu, 0x7bf7c102u, 0xdd80cab6u, 0x1827f438u, 0xbe50ff8cu, 0x8fb8e511u, 0x29cfeea5u,
+0xdf879e4cu, 0x79f095f8u, 0x48188f65u, 0xee6f84d1u, 0x2bc8ba5fu, 0x8dbfb1ebu, 0xbc57ab76u, 0x1a20a0c2u,
+0x8816eaf2u, 0x2e61e146u, 0x1f89fbdbu, 0xb9fef06fu, 0x7c59cee1u, 0xda2ec555u, 0xebc6dfc8u, 0x4db1d47cu,
+0xbbf9a495u, 0x1d8eaf21u, 0x2c66b5bcu, 0x8a11be08u, 0x4fb68086u, 0xe9c18b32u, 0xd82991afu, 0x7e5e9a1bu,
+0xefc8763cu, 0x49bf7d88u, 0x78576715u, 0xde206ca1u, 0x1b87522fu, 0xbdf0599bu, 0x8c184306u, 0x2a6f48b2u,
+0xdc27385bu, 0x7a5033efu, 0x4bb82972u, 0xedcf22c6u, 0x28681c48u, 0x8e1f17fcu, 0xbff70d61u, 0x198006d5u,
+0x47abd36eu, 0xe1dcd8dau, 0xd034c247u, 0x7643c9f3u, 0xb3e4f77du, 0x1593fcc9u, 0x247be654u, 0x820cede0u,
+0x74449d09u, 0xd23396bdu, 0xe3db8c20u, 0x45ac8794u, 0x800bb91au, 0x267cb2aeu, 0x1794a833u, 0xb1e3a387u,
+0x20754fa0u, 0x86024414u, 0xb7ea5e89u, 0x119d553du, 0xd43a6bb3u, 0x724d6007u, 0x43a57a9au, 0xe5d2712eu,
+0x139a01c7u, 0xb5ed0a73u, 0x840510eeu, 0x22721b5au, 0xe7d525d4u, 0x41a22e60u, 0x704a34fdu, 0xd63d3f49u,
+0xcc1d9f8bu, 0x6a6a943fu, 0x5b828ea2u, 0xfdf58516u, 0x3852bb98u, 0x9e25b02cu, 0xafcdaab1u, 0x09baa105u,
+0xfff2d1ecu, 0x5985da58u, 0x686dc0c5u, 0xce1acb71u, 0x0bbdf5ffu, 0xadcafe4bu, 0x9c22e4d6u, 0x3a55ef62u,
+0xabc30345u, 0x0db408f1u, 0x3c5c126cu, 0x9a2b19d8u, 0x5f8c2756u, 0xf9fb2ce2u, 0xc813367fu, 0x6e643dcbu,
+0x982c4d22u, 0x3e5b4696u, 0x0fb35c0bu, 0xa9c457bfu, 0x6c636931u, 0xca146285u, 0xfbfc7818u, 0x5d8b73acu,
+0x03a0a617u, 0xa5d7ada3u, 0x943fb73eu, 0x3248bc8au, 0xf7ef8204u, 0x519889b0u, 0x6070932du, 0xc6079899u,
+0x304fe870u, 0x9638e3c4u, 0xa7d0f959u, 0x01a7f2edu, 0xc400cc63u, 0x6277c7d7u, 0x539fdd4au, 0xf5e8d6feu,
+0x647e3ad9u, 0xc209316du, 0xf3e12bf0u, 0x55962044u, 0x90311ecau, 0x3646157eu, 0x07ae0fe3u, 0xa1d90457u,
+0x579174beu, 0xf1e67f0au, 0xc00e6597u, 0x66796e23u, 0xa3de50adu, 0x05a95b19u, 0x34414184u, 0x92364a30u
+};
+static const unsigned lodepng_crc32_table7[256] = {
+0x00000000u, 0xccaa009eu, 0x4225077du, 0x8e8f07e3u, 0x844a0efau, 0x48e00e64u, 0xc66f0987u, 0x0ac50919u,
+0xd3e51bb5u, 0x1f4f1b2bu, 0x91c01cc8u, 0x5d6a1c56u, 0x57af154fu, 0x9b0515d1u, 0x158a1232u, 0xd92012acu,
+0x7cbb312bu, 0xb01131b5u, 0x3e9e3656u, 0xf23436c8u, 0xf8f13fd1u, 0x345b3f4fu, 0xbad438acu, 0x767e3832u,
+0xaf5e2a9eu, 0x63f42a00u, 0xed7b2de3u, 0x21d12d7du, 0x2b142464u, 0xe7be24fau, 0x69312319u, 0xa59b2387u,
+0xf9766256u, 0x35dc62c8u, 0xbb53652bu, 0x77f965b5u, 0x7d3c6cacu, 0xb1966c32u, 0x3f196bd1u, 0xf3b36b4fu,
+0x2a9379e3u, 0xe639797du, 0x68b67e9eu, 0xa41c7e00u, 0xaed97719u, 0x62737787u, 0xecfc7064u, 0x205670fau,
+0x85cd537du, 0x496753e3u, 0xc7e85400u, 0x0b42549eu, 0x01875d87u, 0xcd2d5d19u, 0x43a25afau, 0x8f085a64u,
+0x562848c8u, 0x9a824856u, 0x140d4fb5u, 0xd8a74f2bu, 0xd2624632u, 0x1ec846acu, 0x9047414fu, 0x5ced41d1u,
+0x299dc2edu, 0xe537c273u, 0x6bb8c590u, 0xa712c50eu, 0xadd7cc17u, 0x617dcc89u, 0xeff2cb6au, 0x2358cbf4u,
+0xfa78d958u, 0x36d2d9c6u, 0xb85dde25u, 0x74f7debbu, 0x7e32d7a2u, 0xb298d73cu, 0x3c17d0dfu, 0xf0bdd041u,
+0x5526f3c6u, 0x998cf358u, 0x1703f4bbu, 0xdba9f425u, 0xd16cfd3cu, 0x1dc6fda2u, 0x9349fa41u, 0x5fe3fadfu,
+0x86c3e873u, 0x4a69e8edu, 0xc4e6ef0eu, 0x084cef90u, 0x0289e689u, 0xce23e617u, 0x40ace1f4u, 0x8c06e16au,
+0xd0eba0bbu, 0x1c41a025u, 0x92cea7c6u, 0x5e64a758u, 0x54a1ae41u, 0x980baedfu, 0x1684a93cu, 0xda2ea9a2u,
+0x030ebb0eu, 0xcfa4bb90u, 0x412bbc73u, 0x8d81bcedu, 0x8744b5f4u, 0x4beeb56au, 0xc561b289u, 0x09cbb217u,
+0xac509190u, 0x60fa910eu, 0xee7596edu, 0x22df9673u, 0x281a9f6au, 0xe4b09ff4u, 0x6a3f9817u, 0xa6959889u,
+0x7fb58a25u, 0xb31f8abbu, 0x3d908d58u, 0xf13a8dc6u, 0xfbff84dfu, 0x37558441u, 0xb9da83a2u, 0x7570833cu,
+0x533b85dau, 0x9f918544u, 0x111e82a7u, 0xddb48239u, 0xd7718b20u, 0x1bdb8bbeu, 0x95548c5du, 0x59fe8cc3u,
+0x80de9e6fu, 0x4c749ef1u, 0xc2fb9912u, 0x0e51998cu, 0x04949095u, 0xc83e900bu, 0x46b197e8u, 0x8a1b9776u,
+0x2f80b4f1u, 0xe32ab46fu, 0x6da5b38cu, 0xa10fb312u, 0xabcaba0bu, 0x6760ba95u, 0xe9efbd76u, 0x2545bde8u,
+0xfc65af44u, 0x30cfafdau, 0xbe40a839u, 0x72eaa8a7u, 0x782fa1beu, 0xb485a120u, 0x3a0aa6c3u, 0xf6a0a65du,
+0xaa4de78cu, 0x66e7e712u, 0xe868e0f1u, 0x24c2e06fu, 0x2e07e976u, 0xe2ade9e8u, 0x6c22ee0bu, 0xa088ee95u,
+0x79a8fc39u, 0xb502fca7u, 0x3b8dfb44u, 0xf727fbdau, 0xfde2f2c3u, 0x3148f25du, 0xbfc7f5beu, 0x736df520u,
+0xd6f6d6a7u, 0x1a5cd639u, 0x94d3d1dau, 0x5879d144u, 0x52bcd85du, 0x9e16d8c3u, 0x1099df20u, 0xdc33dfbeu,
+0x0513cd12u, 0xc9b9cd8cu, 0x4736ca6fu, 0x8b9ccaf1u, 0x8159c3e8u, 0x4df3c376u, 0xc37cc495u, 0x0fd6c40bu,
+0x7aa64737u, 0xb60c47a9u, 0x3883404au, 0xf42940d4u, 0xfeec49cdu, 0x32464953u, 0xbcc94eb0u, 0x70634e2eu,
+0xa9435c82u, 0x65e95c1cu, 0xeb665bffu, 0x27cc5b61u, 0x2d095278u, 0xe1a352e6u, 0x6f2c5505u, 0xa386559bu,
+0x061d761cu, 0xcab77682u, 0x44387161u, 0x889271ffu, 0x825778e6u, 0x4efd7878u, 0xc0727f9bu, 0x0cd87f05u,
+0xd5f86da9u, 0x19526d37u, 0x97dd6ad4u, 0x5b776a4au, 0x51b26353u, 0x9d1863cdu, 0x1397642eu, 0xdf3d64b0u,
+0x83d02561u, 0x4f7a25ffu, 0xc1f5221cu, 0x0d5f2282u, 0x079a2b9bu, 0xcb302b05u, 0x45bf2ce6u, 0x89152c78u,
+0x50353ed4u, 0x9c9f3e4au, 0x121039a9u, 0xdeba3937u, 0xd47f302eu, 0x18d530b0u, 0x965a3753u, 0x5af037cdu,
+0xff6b144au, 0x33c114d4u, 0xbd4e1337u, 0x71e413a9u, 0x7b211ab0u, 0xb78b1a2eu, 0x39041dcdu, 0xf5ae1d53u,
+0x2c8e0fffu, 0xe0240f61u, 0x6eab0882u, 0xa201081cu, 0xa8c40105u, 0x646e019bu, 0xeae10678u, 0x264b06e6u
+};
+/* Computes the cyclic redundancy check as used by PNG chunks*/
+unsigned lodepng_crc32(const unsigned char* data, size_t length) {
+/*Using the Slicing by Eight algorithm*/
+unsigned r = 0xffffffffu;
+while(length >= 8) {
+r = lodepng_crc32_table7[(data[0] ^ (r & 0xffu))] ^
+lodepng_crc32_table6[(data[1] ^ ((r >> 8) & 0xffu))] ^
+lodepng_crc32_table5[(data[2] ^ ((r >> 16) & 0xffu))] ^
+lodepng_crc32_table4[(data[3] ^ ((r >> 24) & 0xffu))] ^
+lodepng_crc32_table3[data[4]] ^
+lodepng_crc32_table2[data[5]] ^
+lodepng_crc32_table1[data[6]] ^
+lodepng_crc32_table0[data[7]];
+data += 8;
+length -= 8;
+}
+while(length--) {
+r = lodepng_crc32_table0[(r ^ *data++) & 0xffu] ^ (r >> 8);
+}
+return r ^ 0xffffffffu;
+}
+#else /* LODEPNG_COMPILE_CRC */
+/*in this case, the function is only declared here, and must be defined externally
+so that it will be linked in.
+Example implementation that uses a much smaller lookup table for memory constrained cases:
+unsigned lodepng_crc32(const unsigned char* data, size_t length) {
+unsigned r = 0xffffffffu;
+static const unsigned table[16] = {
+0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
+0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
+};
+while(length--) {
+r = table[(r ^ *data) & 0xf] ^ (r >> 4);
+r = table[(r ^ (*data >> 4)) & 0xf] ^ (r >> 4);
+data++;
+}
+return r ^ 0xffffffffu;
+}
+*/
+unsigned lodepng_crc32(const unsigned char* data, size_t length);
+#endif /* LODEPNG_COMPILE_CRC */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Reading and writing PNG color channel bits                             / */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first,
+so LodePNGBitWriter and LodePNGBitReader can't be used for those. */
+static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) {
+unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1);
+++(*bitpointer);
+return result;
+}
+/* TODO: make this faster */
+static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) {
+unsigned result = 0;
+size_t i;
+for(i = 0 ; i < nbits; ++i) {
+result <<= 1u;
+result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream);
+}
+return result;
+}
+static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) {
+/*the current bit in bitstream may be 0 or 1 for this to work*/
+if(bit == 0) bitstream[(*bitpointer) >> 3u] &=  (unsigned char)(~(1u << (7u - ((*bitpointer) & 7u))));
+else         bitstream[(*bitpointer) >> 3u] |=  (1u << (7u - ((*bitpointer) & 7u)));
+++(*bitpointer);
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG chunks                                                             / */
+/* ////////////////////////////////////////////////////////////////////////// */
+unsigned lodepng_chunk_length(const unsigned char* chunk) {
+return lodepng_read32bitInt(chunk);
+}
+void lodepng_chunk_type(char type[5], const unsigned char* chunk) {
+unsigned i;
+for(i = 0; i != 4; ++i) type[i] = (char)chunk[4 + i];
+type[4] = 0; /*null termination char*/
+}
+unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) {
+if(lodepng_strlen(type) != 4) return 0;
+return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]);
+}
+unsigned char lodepng_chunk_ancillary(const unsigned char* chunk) {
+return((chunk[4] & 32) != 0);
+}
+unsigned char lodepng_chunk_private(const unsigned char* chunk) {
+return((chunk[6] & 32) != 0);
+}
+unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk) {
+return((chunk[7] & 32) != 0);
+}
+unsigned char* lodepng_chunk_data(unsigned char* chunk) {
+return &chunk[8];
+}
+const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk) {
+return &chunk[8];
+}
+unsigned lodepng_chunk_check_crc(const unsigned char* chunk) {
+unsigned length = lodepng_chunk_length(chunk);
+unsigned CRC = lodepng_read32bitInt(&chunk[length + 8]);
+/*the CRC is taken of the data and the 4 chunk type letters, not the length*/
+unsigned checksum = lodepng_crc32(&chunk[4], length + 4);
+if(CRC != checksum) return 1;
+else return 0;
+}
+void lodepng_chunk_generate_crc(unsigned char* chunk) {
+unsigned length = lodepng_chunk_length(chunk);
+unsigned CRC = lodepng_crc32(&chunk[4], length + 4);
+lodepng_set32bitInt(chunk + 8 + length, CRC);
+}
+unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end) {
+size_t available_size = (size_t)(end - chunk);
+if(chunk >= end || available_size < 12) return end; /*too small to contain a chunk*/
+if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
+&& chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
+/* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
+return chunk + 8;
+} else {
+size_t total_chunk_length;
+if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
+if(total_chunk_length > available_size) return end; /*outside of range*/
+return chunk + total_chunk_length;
+}
+}
+const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end) {
+size_t available_size = (size_t)(end - chunk);
+if(chunk >= end || available_size < 12) return end; /*too small to contain a chunk*/
+if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
+&& chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
+/* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
+return chunk + 8;
+} else {
+size_t total_chunk_length;
+if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
+if(total_chunk_length > available_size) return end; /*outside of range*/
+return chunk + total_chunk_length;
+}
+}
+unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]) {
+for(;;) {
+if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */
+if(lodepng_chunk_type_equals(chunk, type)) return chunk;
+chunk = lodepng_chunk_next(chunk, end);
+}
+}
+const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]) {
+for(;;) {
+if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */
+if(lodepng_chunk_type_equals(chunk, type)) return chunk;
+chunk = lodepng_chunk_next_const(chunk, end);
+}
+}
+unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk) {
+unsigned i;
+size_t total_chunk_length, new_length;
+unsigned char *chunk_start, *new_buffer;
+if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return 77;
+if(lodepng_addofl(*outsize, total_chunk_length, &new_length)) return 77;
+new_buffer = (unsigned char*)lodepng_realloc(*out, new_length);
+if(!new_buffer) return 83; /*alloc fail*/
+(*out) = new_buffer;
+(*outsize) = new_length;
+chunk_start = &(*out)[new_length - total_chunk_length];
+for(i = 0; i != total_chunk_length; ++i) chunk_start[i] = chunk[i];
+return 0;
+}
+/*Sets length and name and allocates the space for data and crc but does not
+set data or crc yet. Returns the start of the chunk in chunk. The start of
+the data is at chunk + 8. To finalize chunk, add the data, then use
+lodepng_chunk_generate_crc */
+static unsigned lodepng_chunk_init(unsigned char** chunk,
+ucvector* out,
+unsigned length, const char* type) {
+size_t new_length = out->size;
+if(lodepng_addofl(new_length, length, &new_length)) return 77;
+if(lodepng_addofl(new_length, 12, &new_length)) return 77;
+if(!ucvector_resize(out, new_length)) return 83; /*alloc fail*/
+*chunk = out->data + new_length - length - 12u;
+/*1: length*/
+lodepng_set32bitInt(*chunk, length);
+/*2: chunk name (4 letters)*/
+lodepng_memcpy(*chunk + 4, type, 4);
+return 0;
+}
+/* like lodepng_chunk_create but with custom allocsize */
+static unsigned lodepng_chunk_createv(ucvector* out,
+unsigned length, const char* type, const unsigned char* data) {
+unsigned char* chunk;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, length, type));
+/*3: the data*/
+lodepng_memcpy(chunk + 8, data, length);
+/*4: CRC (of the chunkname characters and the data)*/
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize,
+unsigned length, const char* type, const unsigned char* data) {
+ucvector v = ucvector_init(*out, *outsize);
+unsigned error = lodepng_chunk_createv(&v, length, type, data);
+*out = v.data;
+*outsize = v.size;
+return error;
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Color types, channels, bits                                            / */
+/* ////////////////////////////////////////////////////////////////////////// */
+/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype.
+Return value is a LodePNG error code.*/
+static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) {
+switch(colortype) {
+case LCT_GREY:       if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break;
+case LCT_RGB:        if(!(                                 bd == 8 || bd == 16)) return 37; break;
+case LCT_PALETTE:    if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8            )) return 37; break;
+case LCT_GREY_ALPHA: if(!(                                 bd == 8 || bd == 16)) return 37; break;
+case LCT_RGBA:       if(!(                                 bd == 8 || bd == 16)) return 37; break;
+case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */
+default: return 31; /* invalid color type */
+}
+return 0; /*allowed color type / bits combination*/
+}
+static unsigned getNumColorChannels(LodePNGColorType colortype) {
+switch(colortype) {
+case LCT_GREY: return 1;
+case LCT_RGB: return 3;
+case LCT_PALETTE: return 1;
+case LCT_GREY_ALPHA: return 2;
+case LCT_RGBA: return 4;
+case LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */
+default: return 0; /*invalid color type*/
+}
+}
+static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) {
+/*bits per pixel is amount of channels * bits per channel*/
+return getNumColorChannels(colortype) * bitdepth;
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+void lodepng_color_mode_init(LodePNGColorMode* info) {
+info->key_defined = 0;
+info->key_r = info->key_g = info->key_b = 0;
+info->colortype = LCT_RGBA;
+info->bitdepth = 8;
+info->palette = 0;
+info->palettesize = 0;
+}
+/*allocates palette memory if needed, and initializes all colors to black*/
+static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) {
+size_t i;
+/*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/
+/*the palette must have room for up to 256 colors with 4 bytes each.*/
+if(!info->palette) info->palette = (unsigned char*)lodepng_malloc(1024);
+if(!info->palette) return; /*alloc fail*/
+for(i = 0; i != 256; ++i) {
+/*Initialize all unused colors with black, the value used for invalid palette indices.
+This is an error according to the PNG spec, but common PNG decoders make it black instead.
+That makes color conversion slightly faster due to no error handling needed.*/
+info->palette[i * 4 + 0] = 0;
+info->palette[i * 4 + 1] = 0;
+info->palette[i * 4 + 2] = 0;
+info->palette[i * 4 + 3] = 255;
+}
+}
+void lodepng_color_mode_cleanup(LodePNGColorMode* info) {
+lodepng_palette_clear(info);
+}
+unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) {
+lodepng_color_mode_cleanup(dest);
+lodepng_memcpy(dest, source, sizeof(LodePNGColorMode));
+if(source->palette) {
+dest->palette = (unsigned char*)lodepng_malloc(1024);
+if(!dest->palette && source->palettesize) return 83; /*alloc fail*/
+lodepng_memcpy(dest->palette, source->palette, source->palettesize * 4);
+}
+return 0;
+}
+LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) {
+LodePNGColorMode result;
+lodepng_color_mode_init(&result);
+result.colortype = colortype;
+result.bitdepth = bitdepth;
+return result;
+}
+static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) {
+size_t i;
+if(a->colortype != b->colortype) return 0;
+if(a->bitdepth != b->bitdepth) return 0;
+if(a->key_defined != b->key_defined) return 0;
+if(a->key_defined) {
+if(a->key_r != b->key_r) return 0;
+if(a->key_g != b->key_g) return 0;
+if(a->key_b != b->key_b) return 0;
+}
+if(a->palettesize != b->palettesize) return 0;
+for(i = 0; i != a->palettesize * 4; ++i) {
+if(a->palette[i] != b->palette[i]) return 0;
+}
+return 1;
+}
+void lodepng_palette_clear(LodePNGColorMode* info) {
+if(info->palette) lodepng_free(info->palette);
+info->palette = 0;
+info->palettesize = 0;
+}
+unsigned lodepng_palette_add(LodePNGColorMode* info,
+unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
+if(!info->palette) /*allocate palette if empty*/ {
+lodepng_color_mode_alloc_palette(info);
+if(!info->palette) return 83; /*alloc fail*/
+}
+if(info->palettesize >= 256) {
+return 108; /*too many palette values*/
+}
+info->palette[4 * info->palettesize + 0] = r;
+info->palette[4 * info->palettesize + 1] = g;
+info->palette[4 * info->palettesize + 2] = b;
+info->palette[4 * info->palettesize + 3] = a;
+++info->palettesize;
+return 0;
+}
+/*calculate bits per pixel out of colortype and bitdepth*/
+unsigned lodepng_get_bpp(const LodePNGColorMode* info) {
+return lodepng_get_bpp_lct(info->colortype, info->bitdepth);
+}
+unsigned lodepng_get_channels(const LodePNGColorMode* info) {
+return getNumColorChannels(info->colortype);
+}
+unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info) {
+return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA;
+}
+unsigned lodepng_is_alpha_type(const LodePNGColorMode* info) {
+return (info->colortype & 4) != 0; /*4 or 6*/
+}
+unsigned lodepng_is_palette_type(const LodePNGColorMode* info) {
+return info->colortype == LCT_PALETTE;
+}
+unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info) {
+size_t i;
+for(i = 0; i != info->palettesize; ++i) {
+if(info->palette[i * 4 + 3] < 255) return 1;
+}
+return 0;
+}
+unsigned lodepng_can_have_alpha(const LodePNGColorMode* info) {
+return info->key_defined
+|| lodepng_is_alpha_type(info)
+|| lodepng_has_palette_alpha(info);
+}
+static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
+size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth);
+size_t n = (size_t)w * (size_t)h;
+return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u;
+}
+size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) {
+return lodepng_get_raw_size_lct(w, h, color->colortype, color->bitdepth);
+}
+#ifdef LODEPNG_COMPILE_PNG
+/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer,
+and in addition has one extra byte per line: the filter byte. So this gives a larger
+result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */
+static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) {
+/* + 1 for the filter byte, and possibly plus padding bits per line. */
+/* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */
+size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u;
+return (size_t)h * line;
+}
+#ifdef LODEPNG_COMPILE_DECODER
+/*Safely checks whether size_t overflow can be caused due to amount of pixels.
+This check is overcautious rather than precise. If this check indicates no overflow,
+you can safely compute in a size_t (but not an unsigned):
+-(size_t)w * (size_t)h * 8
+-amount of bytes in IDAT (including filter, padding and Adam7 bytes)
+-amount of bytes in raw color model
+Returns 1 if overflow possible, 0 if not.
+*/
+static int lodepng_pixel_overflow(unsigned w, unsigned h,
+const LodePNGColorMode* pngcolor, const LodePNGColorMode* rawcolor) {
+size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor));
+size_t numpixels, total;
+size_t line; /* bytes per line in worst case */
+if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1;
+if(lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */
+/* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */
+if(lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return 1;
+if(lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return 1;
+if(lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */
+if(lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */
+return 0; /* no overflow */
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#endif /*LODEPNG_COMPILE_PNG*/
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+static void LodePNGUnknownChunks_init(LodePNGInfo* info) {
+unsigned i;
+for(i = 0; i != 3; ++i) info->unknown_chunks_data[i] = 0;
+for(i = 0; i != 3; ++i) info->unknown_chunks_size[i] = 0;
+}
+static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) {
+unsigned i;
+for(i = 0; i != 3; ++i) lodepng_free(info->unknown_chunks_data[i]);
+}
+static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) {
+unsigned i;
+LodePNGUnknownChunks_cleanup(dest);
+for(i = 0; i != 3; ++i) {
+size_t j;
+dest->unknown_chunks_size[i] = src->unknown_chunks_size[i];
+dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]);
+if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/
+for(j = 0; j < src->unknown_chunks_size[i]; ++j) {
+dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j];
+}
+}
+return 0;
+}
+/******************************************************************************/
+static void LodePNGText_init(LodePNGInfo* info) {
+info->text_num = 0;
+info->text_keys = NULL;
+info->text_strings = NULL;
+}
+static void LodePNGText_cleanup(LodePNGInfo* info) {
+size_t i;
+for(i = 0; i != info->text_num; ++i) {
+string_cleanup(&info->text_keys[i]);
+string_cleanup(&info->text_strings[i]);
+}
+lodepng_free(info->text_keys);
+lodepng_free(info->text_strings);
+}
+static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
+size_t i = 0;
+dest->text_keys = NULL;
+dest->text_strings = NULL;
+dest->text_num = 0;
+for(i = 0; i != source->text_num; ++i) {
+CERROR_TRY_RETURN(lodepng_add_text(dest, source->text_keys[i], source->text_strings[i]));
+}
+return 0;
+}
+static unsigned lodepng_add_text_sized(LodePNGInfo* info, const char* key, const char* str, size_t size) {
+char** new_keys = (char**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1)));
+char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1)));
+if(new_keys) info->text_keys = new_keys;
+if(new_strings) info->text_strings = new_strings;
+if(!new_keys || !new_strings) return 83; /*alloc fail*/
+++info->text_num;
+info->text_keys[info->text_num - 1] = alloc_string(key);
+info->text_strings[info->text_num - 1] = alloc_string_sized(str, size);
+if(!info->text_keys[info->text_num - 1] || !info->text_strings[info->text_num - 1]) return 83; /*alloc fail*/
+return 0;
+}
+unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) {
+return lodepng_add_text_sized(info, key, str, lodepng_strlen(str));
+}
+void lodepng_clear_text(LodePNGInfo* info) {
+LodePNGText_cleanup(info);
+}
+/******************************************************************************/
+static void LodePNGIText_init(LodePNGInfo* info) {
+info->itext_num = 0;
+info->itext_keys = NULL;
+info->itext_langtags = NULL;
+info->itext_transkeys = NULL;
+info->itext_strings = NULL;
+}
+static void LodePNGIText_cleanup(LodePNGInfo* info) {
+size_t i;
+for(i = 0; i != info->itext_num; ++i) {
+string_cleanup(&info->itext_keys[i]);
+string_cleanup(&info->itext_langtags[i]);
+string_cleanup(&info->itext_transkeys[i]);
+string_cleanup(&info->itext_strings[i]);
+}
+lodepng_free(info->itext_keys);
+lodepng_free(info->itext_langtags);
+lodepng_free(info->itext_transkeys);
+lodepng_free(info->itext_strings);
+}
+static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
+size_t i = 0;
+dest->itext_keys = NULL;
+dest->itext_langtags = NULL;
+dest->itext_transkeys = NULL;
+dest->itext_strings = NULL;
+dest->itext_num = 0;
+for(i = 0; i != source->itext_num; ++i) {
+CERROR_TRY_RETURN(lodepng_add_itext(dest, source->itext_keys[i], source->itext_langtags[i],
+source->itext_transkeys[i], source->itext_strings[i]));
+}
+return 0;
+}
+void lodepng_clear_itext(LodePNGInfo* info) {
+LodePNGIText_cleanup(info);
+}
+static unsigned lodepng_add_itext_sized(LodePNGInfo* info, const char* key, const char* langtag,
+const char* transkey, const char* str, size_t size) {
+char** new_keys = (char**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1)));
+char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1)));
+char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1)));
+char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1)));
+if(new_keys) info->itext_keys = new_keys;
+if(new_langtags) info->itext_langtags = new_langtags;
+if(new_transkeys) info->itext_transkeys = new_transkeys;
+if(new_strings) info->itext_strings = new_strings;
+if(!new_keys || !new_langtags || !new_transkeys || !new_strings) return 83; /*alloc fail*/
+++info->itext_num;
+info->itext_keys[info->itext_num - 1] = alloc_string(key);
+info->itext_langtags[info->itext_num - 1] = alloc_string(langtag);
+info->itext_transkeys[info->itext_num - 1] = alloc_string(transkey);
+info->itext_strings[info->itext_num - 1] = alloc_string_sized(str, size);
+return 0;
+}
+unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
+const char* transkey, const char* str) {
+return lodepng_add_itext_sized(info, key, langtag, transkey, str, lodepng_strlen(str));
+}
+/* same as set but does not delete */
+static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) {
+if(profile_size == 0) return 100; /*invalid ICC profile size*/
+info->iccp_name = alloc_string(name);
+info->iccp_profile = (unsigned char*)lodepng_malloc(profile_size);
+if(!info->iccp_name || !info->iccp_profile) return 83; /*alloc fail*/
+lodepng_memcpy(info->iccp_profile, profile, profile_size);
+info->iccp_profile_size = profile_size;
+return 0; /*ok*/
+}
+unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) {
+if(info->iccp_name) lodepng_clear_icc(info);
+info->iccp_defined = 1;
+return lodepng_assign_icc(info, name, profile, profile_size);
+}
+void lodepng_clear_icc(LodePNGInfo* info) {
+string_cleanup(&info->iccp_name);
+lodepng_free(info->iccp_profile);
+info->iccp_profile = NULL;
+info->iccp_profile_size = 0;
+info->iccp_defined = 0;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+void lodepng_info_init(LodePNGInfo* info) {
+lodepng_color_mode_init(&info->color);
+info->interlace_method = 0;
+info->compression_method = 0;
+info->filter_method = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+info->background_defined = 0;
+info->background_r = info->background_g = info->background_b = 0;
+LodePNGText_init(info);
+LodePNGIText_init(info);
+info->time_defined = 0;
+info->phys_defined = 0;
+info->gama_defined = 0;
+info->chrm_defined = 0;
+info->srgb_defined = 0;
+info->iccp_defined = 0;
+info->iccp_name = NULL;
+info->iccp_profile = NULL;
+info->sbit_defined = 0;
+info->sbit_r = info->sbit_g = info->sbit_b = info->sbit_a = 0;
+LodePNGUnknownChunks_init(info);
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+void lodepng_info_cleanup(LodePNGInfo* info) {
+lodepng_color_mode_cleanup(&info->color);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+LodePNGText_cleanup(info);
+LodePNGIText_cleanup(info);
+lodepng_clear_icc(info);
+LodePNGUnknownChunks_cleanup(info);
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
+lodepng_info_cleanup(dest);
+lodepng_memcpy(dest, source, sizeof(LodePNGInfo));
+lodepng_color_mode_init(&dest->color);
+CERROR_TRY_RETURN(lodepng_color_mode_copy(&dest->color, &source->color));
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+CERROR_TRY_RETURN(LodePNGText_copy(dest, source));
+CERROR_TRY_RETURN(LodePNGIText_copy(dest, source));
+if(source->iccp_defined) {
+CERROR_TRY_RETURN(lodepng_assign_icc(dest, source->iccp_name, source->iccp_profile, source->iccp_profile_size));
+}
+LodePNGUnknownChunks_init(dest);
+CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source));
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+return 0;
+}
+/* ////////////////////////////////////////////////////////////////////////// */
+/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/
+static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) {
+unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/
+/*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/
+unsigned p = index & m;
+in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/
+in = in << (bits * (m - p));
+if(p == 0) out[index * bits / 8u] = in;
+else out[index * bits / 8u] |= in;
+}
+typedef struct ColorTree ColorTree;
+/*
+One node of a color tree
+This is the data structure used to count the number of unique colors and to get a palette
+index for a color. It's like an octree, but because the alpha channel is used too, each
+node has 16 instead of 8 children.
+*/
+struct ColorTree {
+ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/
+int index; /*the payload. Only has a meaningful value if this is in the last level*/
+};
+static void color_tree_init(ColorTree* tree) {
+lodepng_memset(tree->children, 0, 16 * sizeof(*tree->children));
+tree->index = -1;
+}
+static void color_tree_cleanup(ColorTree* tree) {
+int i;
+for(i = 0; i != 16; ++i) {
+if(tree->children[i]) {
+color_tree_cleanup(tree->children[i]);
+lodepng_free(tree->children[i]);
+}
+}
+}
+/*returns -1 if color not present, its index otherwise*/
+static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
+int bit = 0;
+for(bit = 0; bit < 8; ++bit) {
+int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
+if(!tree->children[i]) return -1;
+else tree = tree->children[i];
+}
+return tree ? tree->index : -1;
+}
+#ifdef LODEPNG_COMPILE_ENCODER
+static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
+return color_tree_get(tree, r, g, b, a) >= 0;
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+/*color is not allowed to already exist.
+Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist")
+Returns error code, or 0 if ok*/
+static unsigned color_tree_add(ColorTree* tree,
+unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) {
+int bit;
+for(bit = 0; bit < 8; ++bit) {
+int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
+if(!tree->children[i]) {
+tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree));
+if(!tree->children[i]) return 83; /*alloc fail*/
+color_tree_init(tree->children[i]);
+}
+tree = tree->children[i];
+}
+tree->index = (int)index;
+return 0;
+}
+/*put a pixel, given its RGBA color, into image of any color type*/
+static unsigned rgba8ToPixel(unsigned char* out, size_t i,
+const LodePNGColorMode* mode, ColorTree* tree /*for palette*/,
+unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
+if(mode->colortype == LCT_GREY) {
+unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/
+if(mode->bitdepth == 8) out[i] = gray;
+else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray;
+else {
+/*take the most significant bits of gray*/
+gray = ((unsigned)gray >> (8u - mode->bitdepth)) & ((1u << mode->bitdepth) - 1u);
+addColorBits(out, i, mode->bitdepth, gray);
+}
+} else if(mode->colortype == LCT_RGB) {
+if(mode->bitdepth == 8) {
+out[i * 3 + 0] = r;
+out[i * 3 + 1] = g;
+out[i * 3 + 2] = b;
+} else {
+out[i * 6 + 0] = out[i * 6 + 1] = r;
+out[i * 6 + 2] = out[i * 6 + 3] = g;
+out[i * 6 + 4] = out[i * 6 + 5] = b;
+}
+} else if(mode->colortype == LCT_PALETTE) {
+int index = color_tree_get(tree, r, g, b, a);
+if(index < 0) return 82; /*color not in palette*/
+if(mode->bitdepth == 8) out[i] = index;
+else addColorBits(out, i, mode->bitdepth, (unsigned)index);
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/
+if(mode->bitdepth == 8) {
+out[i * 2 + 0] = gray;
+out[i * 2 + 1] = a;
+} else if(mode->bitdepth == 16) {
+out[i * 4 + 0] = out[i * 4 + 1] = gray;
+out[i * 4 + 2] = out[i * 4 + 3] = a;
+}
+} else if(mode->colortype == LCT_RGBA) {
+if(mode->bitdepth == 8) {
+out[i * 4 + 0] = r;
+out[i * 4 + 1] = g;
+out[i * 4 + 2] = b;
+out[i * 4 + 3] = a;
+} else {
+out[i * 8 + 0] = out[i * 8 + 1] = r;
+out[i * 8 + 2] = out[i * 8 + 3] = g;
+out[i * 8 + 4] = out[i * 8 + 5] = b;
+out[i * 8 + 6] = out[i * 8 + 7] = a;
+}
+}
+return 0; /*no error*/
+}
+/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/
+static void rgba16ToPixel(unsigned char* out, size_t i,
+const LodePNGColorMode* mode,
+unsigned short r, unsigned short g, unsigned short b, unsigned short a) {
+if(mode->colortype == LCT_GREY) {
+unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/
+out[i * 2 + 0] = (gray >> 8) & 255;
+out[i * 2 + 1] = gray & 255;
+} else if(mode->colortype == LCT_RGB) {
+out[i * 6 + 0] = (r >> 8) & 255;
+out[i * 6 + 1] = r & 255;
+out[i * 6 + 2] = (g >> 8) & 255;
+out[i * 6 + 3] = g & 255;
+out[i * 6 + 4] = (b >> 8) & 255;
+out[i * 6 + 5] = b & 255;
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/
+out[i * 4 + 0] = (gray >> 8) & 255;
+out[i * 4 + 1] = gray & 255;
+out[i * 4 + 2] = (a >> 8) & 255;
+out[i * 4 + 3] = a & 255;
+} else if(mode->colortype == LCT_RGBA) {
+out[i * 8 + 0] = (r >> 8) & 255;
+out[i * 8 + 1] = r & 255;
+out[i * 8 + 2] = (g >> 8) & 255;
+out[i * 8 + 3] = g & 255;
+out[i * 8 + 4] = (b >> 8) & 255;
+out[i * 8 + 5] = b & 255;
+out[i * 8 + 6] = (a >> 8) & 255;
+out[i * 8 + 7] = a & 255;
+}
+}
+/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/
+static void getPixelColorRGBA8(unsigned char* r, unsigned char* g,
+unsigned char* b, unsigned char* a,
+const unsigned char* in, size_t i,
+const LodePNGColorMode* mode) {
+if(mode->colortype == LCT_GREY) {
+if(mode->bitdepth == 8) {
+*r = *g = *b = in[i];
+if(mode->key_defined && *r == mode->key_r) *a = 0;
+else *a = 255;
+} else if(mode->bitdepth == 16) {
+*r = *g = *b = in[i * 2 + 0];
+if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
+else *a = 255;
+} else {
+unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
+size_t j = i * mode->bitdepth;
+unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
+*r = *g = *b = (value * 255) / highest;
+if(mode->key_defined && value == mode->key_r) *a = 0;
+else *a = 255;
+}
+} else if(mode->colortype == LCT_RGB) {
+if(mode->bitdepth == 8) {
+*r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2];
+if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0;
+else *a = 255;
+} else {
+*r = in[i * 6 + 0];
+*g = in[i * 6 + 2];
+*b = in[i * 6 + 4];
+if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+&& 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+&& 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
+else *a = 255;
+}
+} else if(mode->colortype == LCT_PALETTE) {
+unsigned index;
+if(mode->bitdepth == 8) index = in[i];
+else {
+size_t j = i * mode->bitdepth;
+index = readBitsFromReversedStream(&j, in, mode->bitdepth);
+}
+/*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
+*r = mode->palette[index * 4 + 0];
+*g = mode->palette[index * 4 + 1];
+*b = mode->palette[index * 4 + 2];
+*a = mode->palette[index * 4 + 3];
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+if(mode->bitdepth == 8) {
+*r = *g = *b = in[i * 2 + 0];
+*a = in[i * 2 + 1];
+} else {
+*r = *g = *b = in[i * 4 + 0];
+*a = in[i * 4 + 2];
+}
+} else if(mode->colortype == LCT_RGBA) {
+if(mode->bitdepth == 8) {
+*r = in[i * 4 + 0];
+*g = in[i * 4 + 1];
+*b = in[i * 4 + 2];
+*a = in[i * 4 + 3];
+} else {
+*r = in[i * 8 + 0];
+*g = in[i * 8 + 2];
+*b = in[i * 8 + 4];
+*a = in[i * 8 + 6];
+}
+}
+}
+/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color
+mode test cases, optimized to convert the colors much faster, when converting
+to the common case of RGBA with 8 bit per channel. buffer must be RGBA with
+enough memory.*/
+static void getPixelColorsRGBA8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels,
+const unsigned char* LODEPNG_RESTRICT in,
+const LodePNGColorMode* mode) {
+unsigned num_channels = 4;
+size_t i;
+if(mode->colortype == LCT_GREY) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i];
+buffer[3] = 255;
+}
+if(mode->key_defined) {
+buffer -= numpixels * num_channels;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+if(buffer[0] == mode->key_r) buffer[3] = 0;
+}
+}
+} else if(mode->bitdepth == 16) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 2];
+buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255;
+}
+} else {
+unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
+size_t j = 0;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
+buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest;
+buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255;
+}
+}
+} else if(mode->colortype == LCT_RGB) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+lodepng_memcpy(buffer, &in[i * 3], 3);
+buffer[3] = 255;
+}
+if(mode->key_defined) {
+buffer -= numpixels * num_channels;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+if(buffer[0] == mode->key_r && buffer[1]== mode->key_g && buffer[2] == mode->key_b) buffer[3] = 0;
+}
+}
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = in[i * 6 + 0];
+buffer[1] = in[i * 6 + 2];
+buffer[2] = in[i * 6 + 4];
+buffer[3] = mode->key_defined
+&& 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+&& 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+&& 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255;
+}
+}
+} else if(mode->colortype == LCT_PALETTE) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned index = in[i];
+/*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
+lodepng_memcpy(buffer, &mode->palette[index * 4], 4);
+}
+} else {
+size_t j = 0;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth);
+/*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
+lodepng_memcpy(buffer, &mode->palette[index * 4], 4);
+}
+}
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0];
+buffer[3] = in[i * 2 + 1];
+}
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0];
+buffer[3] = in[i * 4 + 2];
+}
+}
+} else if(mode->colortype == LCT_RGBA) {
+if(mode->bitdepth == 8) {
+lodepng_memcpy(buffer, in, numpixels * 4);
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = in[i * 8 + 0];
+buffer[1] = in[i * 8 + 2];
+buffer[2] = in[i * 8 + 4];
+buffer[3] = in[i * 8 + 6];
+}
+}
+}
+}
+/*Similar to getPixelColorsRGBA8, but with 3-channel RGB output.*/
+static void getPixelColorsRGB8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels,
+const unsigned char* LODEPNG_RESTRICT in,
+const LodePNGColorMode* mode) {
+const unsigned num_channels = 3;
+size_t i;
+if(mode->colortype == LCT_GREY) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i];
+}
+} else if(mode->bitdepth == 16) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 2];
+}
+} else {
+unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
+size_t j = 0;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
+buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest;
+}
+}
+} else if(mode->colortype == LCT_RGB) {
+if(mode->bitdepth == 8) {
+lodepng_memcpy(buffer, in, numpixels * 3);
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = in[i * 6 + 0];
+buffer[1] = in[i * 6 + 2];
+buffer[2] = in[i * 6 + 4];
+}
+}
+} else if(mode->colortype == LCT_PALETTE) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned index = in[i];
+/*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
+lodepng_memcpy(buffer, &mode->palette[index * 4], 3);
+}
+} else {
+size_t j = 0;
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth);
+/*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
+lodepng_memcpy(buffer, &mode->palette[index * 4], 3);
+}
+}
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0];
+}
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0];
+}
+}
+} else if(mode->colortype == LCT_RGBA) {
+if(mode->bitdepth == 8) {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+lodepng_memcpy(buffer, &in[i * 4], 3);
+}
+} else {
+for(i = 0; i != numpixels; ++i, buffer += num_channels) {
+buffer[0] = in[i * 8 + 0];
+buffer[1] = in[i * 8 + 2];
+buffer[2] = in[i * 8 + 4];
+}
+}
+}
+}
+/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with
+given color type, but the given color type must be 16-bit itself.*/
+static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a,
+const unsigned char* in, size_t i, const LodePNGColorMode* mode) {
+if(mode->colortype == LCT_GREY) {
+*r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1];
+if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
+else *a = 65535;
+} else if(mode->colortype == LCT_RGB) {
+*r = 256u * in[i * 6 + 0] + in[i * 6 + 1];
+*g = 256u * in[i * 6 + 2] + in[i * 6 + 3];
+*b = 256u * in[i * 6 + 4] + in[i * 6 + 5];
+if(mode->key_defined
+&& 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+&& 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+&& 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
+else *a = 65535;
+} else if(mode->colortype == LCT_GREY_ALPHA) {
+*r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1];
+*a = 256u * in[i * 4 + 2] + in[i * 4 + 3];
+} else if(mode->colortype == LCT_RGBA) {
+*r = 256u * in[i * 8 + 0] + in[i * 8 + 1];
+*g = 256u * in[i * 8 + 2] + in[i * 8 + 3];
+*b = 256u * in[i * 8 + 4] + in[i * 8 + 5];
+*a = 256u * in[i * 8 + 6] + in[i * 8 + 7];
+}
+}
+unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
+const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
+unsigned w, unsigned h) {
+size_t i;
+ColorTree tree;
+size_t numpixels = (size_t)w * (size_t)h;
+unsigned error = 0;
+if(mode_in->colortype == LCT_PALETTE && !mode_in->palette) {
+return 107; /* error: must provide palette if input mode is palette */
+}
+if(lodepng_color_mode_equal(mode_out, mode_in)) {
+size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
+lodepng_memcpy(out, in, numbytes);
+return 0;
+}
+if(mode_out->colortype == LCT_PALETTE) {
+size_t palettesize = mode_out->palettesize;
+const unsigned char* palette = mode_out->palette;
+size_t palsize = (size_t)1u << mode_out->bitdepth;
+/*if the user specified output palette but did not give the values, assume
+they want the values of the input color type (assuming that one is palette).
+Note that we never create a new palette ourselves.*/
+if(palettesize == 0) {
+palettesize = mode_in->palettesize;
+palette = mode_in->palette;
+/*if the input was also palette with same bitdepth, then the color types are also
+equal, so copy literally. This to preserve the exact indices that were in the PNG
+even in case there are duplicate colors in the palette.*/
+if(mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) {
+size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
+lodepng_memcpy(out, in, numbytes);
+return 0;
+}
+}
+if(palettesize < palsize) palsize = palettesize;
+color_tree_init(&tree);
+for(i = 0; i != palsize; ++i) {
+const unsigned char* p = &palette[i * 4];
+error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i);
+if(error) break;
+}
+}
+if(!error) {
+if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) {
+for(i = 0; i != numpixels; ++i) {
+unsigned short r = 0, g = 0, b = 0, a = 0;
+getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
+rgba16ToPixel(out, i, mode_out, r, g, b, a);
+}
+} else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) {
+getPixelColorsRGBA8(out, numpixels, in, mode_in);
+} else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) {
+getPixelColorsRGB8(out, numpixels, in, mode_in);
+} else {
+unsigned char r = 0, g = 0, b = 0, a = 0;
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
+error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a);
+if(error) break;
+}
+}
+}
+if(mode_out->colortype == LCT_PALETTE) {
+color_tree_cleanup(&tree);
+}
+return error;
+}
+/* Converts a single rgb color without alpha from one type to another, color bits truncated to
+their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow
+function, do not use to process all pixels of an image. Alpha channel not supported on purpose:
+this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the
+specification it looks like bKGD should ignore the alpha values of the palette since it can use
+any palette index but doesn't have an alpha channel. Idem with ignoring color key. */
+unsigned lodepng_convert_rgb(
+unsigned* r_out, unsigned* g_out, unsigned* b_out,
+unsigned r_in, unsigned g_in, unsigned b_in,
+const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in) {
+unsigned r = 0, g = 0, b = 0;
+unsigned mul = 65535 / ((1u << mode_in->bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/
+unsigned shift = 16 - mode_out->bitdepth;
+if(mode_in->colortype == LCT_GREY || mode_in->colortype == LCT_GREY_ALPHA) {
+r = g = b = r_in * mul;
+} else if(mode_in->colortype == LCT_RGB || mode_in->colortype == LCT_RGBA) {
+r = r_in * mul;
+g = g_in * mul;
+b = b_in * mul;
+} else if(mode_in->colortype == LCT_PALETTE) {
+if(r_in >= mode_in->palettesize) return 82;
+r = mode_in->palette[r_in * 4 + 0] * 257u;
+g = mode_in->palette[r_in * 4 + 1] * 257u;
+b = mode_in->palette[r_in * 4 + 2] * 257u;
+} else {
+return 31;
+}
+/* now convert to output format */
+if(mode_out->colortype == LCT_GREY || mode_out->colortype == LCT_GREY_ALPHA) {
+*r_out = r >> shift ;
+} else if(mode_out->colortype == LCT_RGB || mode_out->colortype == LCT_RGBA) {
+*r_out = r >> shift ;
+*g_out = g >> shift ;
+*b_out = b >> shift ;
+} else if(mode_out->colortype == LCT_PALETTE) {
+unsigned i;
+/* a 16-bit color cannot be in the palette */
+if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82;
+for(i = 0; i < mode_out->palettesize; i++) {
+unsigned j = i * 4;
+if((r >> 8) == mode_out->palette[j + 0] && (g >> 8) == mode_out->palette[j + 1] &&
+(b >> 8) == mode_out->palette[j + 2]) {
+*r_out = i;
+return 0;
+}
+}
+return 82;
+} else {
+return 31;
+}
+return 0;
+}
+#ifdef LODEPNG_COMPILE_ENCODER
+void lodepng_color_stats_init(LodePNGColorStats* stats) {
+/*stats*/
+stats->colored = 0;
+stats->key = 0;
+stats->key_r = stats->key_g = stats->key_b = 0;
+stats->alpha = 0;
+stats->numcolors = 0;
+stats->bits = 1;
+stats->numpixels = 0;
+/*settings*/
+stats->allow_palette = 1;
+stats->allow_greyscale = 1;
+}
+/*function used for debug purposes with C++*/
+/*void printColorStats(LodePNGColorStats* p) {
+std::cout << "colored: " << (int)p->colored << ", ";
+std::cout << "key: " << (int)p->key << ", ";
+std::cout << "key_r: " << (int)p->key_r << ", ";
+std::cout << "key_g: " << (int)p->key_g << ", ";
+std::cout << "key_b: " << (int)p->key_b << ", ";
+std::cout << "alpha: " << (int)p->alpha << ", ";
+std::cout << "numcolors: " << (int)p->numcolors << ", ";
+std::cout << "bits: " << (int)p->bits << std::endl;
+}*/
+/*Returns how many bits needed to represent given value (max 8 bit)*/
+static unsigned getValueRequiredBits(unsigned char value) {
+if(value == 0 || value == 255) return 1;
+/*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/
+if(value % 17 == 0) return value % 85 == 0 ? 2 : 4;
+return 8;
+}
+/*stats must already have been inited. */
+unsigned lodepng_compute_color_stats(LodePNGColorStats* stats,
+const unsigned char* in, unsigned w, unsigned h,
+const LodePNGColorMode* mode_in) {
+size_t i;
+ColorTree tree;
+size_t numpixels = (size_t)w * (size_t)h;
+unsigned error = 0;
+/* mark things as done already if it would be impossible to have a more expensive case */
+unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0;
+unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1;
+unsigned numcolors_done = 0;
+unsigned bpp = lodepng_get_bpp(mode_in);
+unsigned bits_done = (stats->bits == 1 && bpp == 1) ? 1 : 0;
+unsigned sixteen = 0; /* whether the input image is 16 bit */
+unsigned maxnumcolors = 257;
+if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, stats->numcolors + (1u << bpp));
+stats->numpixels += numpixels;
+/*if palette not allowed, no need to compute numcolors*/
+if(!stats->allow_palette) numcolors_done = 1;
+color_tree_init(&tree);
+/*If the stats was already filled in from previous data, fill its palette in tree
+and mark things as done already if we know they are the most expensive case already*/
+if(stats->alpha) alpha_done = 1;
+if(stats->colored) colored_done = 1;
+if(stats->bits == 16) numcolors_done = 1;
+if(stats->bits >= bpp) bits_done = 1;
+if(stats->numcolors >= maxnumcolors) numcolors_done = 1;
+if(!numcolors_done) {
+for(i = 0; i < stats->numcolors; i++) {
+const unsigned char* color = &stats->palette[i * 4];
+error = color_tree_add(&tree, color[0], color[1], color[2], color[3], i);
+if(error) goto cleanup;
+}
+}
+/*Check if the 16-bit input is truly 16-bit*/
+if(mode_in->bitdepth == 16 && !sixteen) {
+unsigned short r = 0, g = 0, b = 0, a = 0;
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
+if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) ||
+(b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ {
+stats->bits = 16;
+sixteen = 1;
+bits_done = 1;
+numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/
+break;
+}
+}
+}
+if(sixteen) {
+unsigned short r = 0, g = 0, b = 0, a = 0;
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
+if(!colored_done && (r != g || r != b)) {
+stats->colored = 1;
+colored_done = 1;
+}
+if(!alpha_done) {
+unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b);
+if(a != 65535 && (a != 0 || (stats->key && !matchkey))) {
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+} else if(a == 0 && !stats->alpha && !stats->key) {
+stats->key = 1;
+stats->key_r = r;
+stats->key_g = g;
+stats->key_b = b;
+} else if(a == 65535 && stats->key && matchkey) {
+/* Color key cannot be used if an opaque pixel also has that RGB color. */
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+}
+}
+if(alpha_done && numcolors_done && colored_done && bits_done) break;
+}
+if(stats->key && !stats->alpha) {
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
+if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) {
+/* Color key cannot be used if an opaque pixel also has that RGB color. */
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+}
+}
+}
+} else /* < 16-bit */ {
+unsigned char r = 0, g = 0, b = 0, a = 0;
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
+if(!bits_done && stats->bits < 8) {
+/*only r is checked, < 8 bits is only relevant for grayscale*/
+unsigned bits = getValueRequiredBits(r);
+if(bits > stats->bits) stats->bits = bits;
+}
+bits_done = (stats->bits >= bpp);
+if(!colored_done && (r != g || r != b)) {
+stats->colored = 1;
+colored_done = 1;
+if(stats->bits < 8) stats->bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/
+}
+if(!alpha_done) {
+unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b);
+if(a != 255 && (a != 0 || (stats->key && !matchkey))) {
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
+} else if(a == 0 && !stats->alpha && !stats->key) {
+stats->key = 1;
+stats->key_r = r;
+stats->key_g = g;
+stats->key_b = b;
+} else if(a == 255 && stats->key && matchkey) {
+/* Color key cannot be used if an opaque pixel also has that RGB color. */
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
+}
+}
+if(!numcolors_done) {
+if(!color_tree_has(&tree, r, g, b, a)) {
+error = color_tree_add(&tree, r, g, b, a, stats->numcolors);
+if(error) goto cleanup;
+if(stats->numcolors < 256) {
+unsigned char* p = stats->palette;
+unsigned n = stats->numcolors;
+p[n * 4 + 0] = r;
+p[n * 4 + 1] = g;
+p[n * 4 + 2] = b;
+p[n * 4 + 3] = a;
+}
+++stats->numcolors;
+numcolors_done = stats->numcolors >= maxnumcolors;
+}
+}
+if(alpha_done && numcolors_done && colored_done && bits_done) break;
+}
+if(stats->key && !stats->alpha) {
+for(i = 0; i != numpixels; ++i) {
+getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
+if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) {
+/* Color key cannot be used if an opaque pixel also has that RGB color. */
+stats->alpha = 1;
+stats->key = 0;
+alpha_done = 1;
+if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
+}
+}
+}
+/*make the stats's key always 16-bit for consistency - repeat each byte twice*/
+stats->key_r += (stats->key_r << 8);
+stats->key_g += (stats->key_g << 8);
+stats->key_b += (stats->key_b << 8);
+}
+cleanup:
+color_tree_cleanup(&tree);
+return error;
+}
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*Adds a single color to the color stats. The stats must already have been inited. The color must be given as 16-bit
+(with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for
+all pixels of an image but only for a few additional values. */
+static unsigned lodepng_color_stats_add(LodePNGColorStats* stats,
+unsigned r, unsigned g, unsigned b, unsigned a) {
+unsigned error = 0;
+unsigned char image[8];
+LodePNGColorMode mode;
+lodepng_color_mode_init(&mode);
+image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g;
+image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a;
+mode.bitdepth = 16;
+mode.colortype = LCT_RGBA;
+error = lodepng_compute_color_stats(stats, image, 1, 1, &mode);
+lodepng_color_mode_cleanup(&mode);
+return error;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+/*Computes a minimal PNG color model that can contain all colors as indicated by the stats.
+The stats should be computed with lodepng_compute_color_stats.
+mode_in is raw color profile of the image the stats were computed on, to copy palette order from when relevant.
+Minimal PNG color model means the color type and bit depth that gives smallest amount of bits in the output image,
+e.g. gray if only grayscale pixels, palette if less than 256 colors, color key if only single transparent color, ...
+This is used if auto_convert is enabled (it is by default).
+*/
+static unsigned auto_choose_color(LodePNGColorMode* mode_out,
+const LodePNGColorMode* mode_in,
+const LodePNGColorStats* stats) {
+unsigned error = 0;
+unsigned palettebits;
+size_t i, n;
+size_t numpixels = stats->numpixels;
+unsigned palette_ok, gray_ok;
+unsigned alpha = stats->alpha;
+unsigned key = stats->key;
+unsigned bits = stats->bits;
+mode_out->key_defined = 0;
+if(key && numpixels <= 16) {
+alpha = 1; /*too few pixels to justify tRNS chunk overhead*/
+key = 0;
+if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
+}
+gray_ok = !stats->colored;
+if(!stats->allow_greyscale) gray_ok = 0;
+if(!gray_ok && bits < 8) bits = 8;
+n = stats->numcolors;
+palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8));
+palette_ok = n <= 256 && bits <= 8 && n != 0; /*n==0 means likely numcolors wasn't computed*/
+if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/
+if(gray_ok && !alpha && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/
+if(!stats->allow_palette) palette_ok = 0;
+if(palette_ok) {
+const unsigned char* p = stats->palette;
+lodepng_palette_clear(mode_out); /*remove potential earlier palette*/
+for(i = 0; i != stats->numcolors; ++i) {
+error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]);
+if(error) break;
+}
+mode_out->colortype = LCT_PALETTE;
+mode_out->bitdepth = palettebits;
+if(mode_in->colortype == LCT_PALETTE && mode_in->palettesize >= mode_out->palettesize
+&& mode_in->bitdepth == mode_out->bitdepth) {
+/*If input should have same palette colors, keep original to preserve its order and prevent conversion*/
+lodepng_color_mode_cleanup(mode_out); /*clears palette, keeps the above set colortype and bitdepth fields as-is*/
+lodepng_color_mode_copy(mode_out, mode_in);
+}
+} else /*8-bit or 16-bit per channel*/ {
+mode_out->bitdepth = bits;
+mode_out->colortype = alpha ? (gray_ok ? LCT_GREY_ALPHA : LCT_RGBA)
+: (gray_ok ? LCT_GREY : LCT_RGB);
+if(key) {
+unsigned mask = (1u << mode_out->bitdepth) - 1u; /*stats always uses 16-bit, mask converts it*/
+mode_out->key_r = stats->key_r & mask;
+mode_out->key_g = stats->key_g & mask;
+mode_out->key_b = stats->key_b & mask;
+mode_out->key_defined = 1;
+}
+}
+return error;
+}
+#endif /* #ifdef LODEPNG_COMPILE_ENCODER */
+/*Paeth predictor, used by PNG filter type 4*/
+static unsigned char paethPredictor(unsigned char a, unsigned char b, unsigned char c) {
+/* the subtractions of unsigned char cast it to a signed type.
+With gcc, short is faster than int, with clang int is as fast (as of april 2023)*/
+short pa = (b - c) < 0 ? -(b - c) : (b - c);
+short pb = (a - c) < 0 ? -(a - c) : (a - c);
+/* writing it out like this compiles to something faster than introducing a temp variable*/
+short pc = (a + b - c - c) < 0 ? -(a + b - c - c) : (a + b - c - c);
+/* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */
+if(pb < pa) { a = b; pa = pb; }
+return (pc < pa) ? c : a;
+}
+/*shared values used by multiple Adam7 related functions*/
+static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/
+static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/
+static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/
+static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/
+/*
+Outputs various dimensions and positions in the image related to the Adam7 reduced images.
+passw: output containing the width of the 7 passes
+passh: output containing the height of the 7 passes
+filter_passstart: output containing the index of the start and end of each
+reduced image with filter bytes
+padded_passstart output containing the index of the start and end of each
+reduced image when without filter bytes but with padded scanlines
+passstart: output containing the index of the start and end of each reduced
+image without padding between scanlines, but still padding between the images
+w, h: width and height of non-interlaced image
+bpp: bits per pixel
+"padded" is only relevant if bpp is less than 8 and a scanline or image does not
+end at a full byte
+*/
+static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8],
+size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) {
+/*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/
+unsigned i;
+/*calculate width and height in pixels of each pass*/
+for(i = 0; i != 7; ++i) {
+passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i];
+passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i];
+if(passw[i] == 0) passh[i] = 0;
+if(passh[i] == 0) passw[i] = 0;
+}
+filter_passstart[0] = padded_passstart[0] = passstart[0] = 0;
+for(i = 0; i != 7; ++i) {
+/*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/
+filter_passstart[i + 1] = filter_passstart[i]
++ ((passw[i] && passh[i]) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0);
+/*bits padded if needed to fill full byte at end of each scanline*/
+padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u);
+/*only padded at end of reduced image*/
+passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u;
+}
+}
+#ifdef LODEPNG_COMPILE_DECODER
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG Decoder                                                            / */
+/* ////////////////////////////////////////////////////////////////////////// */
+/*read the information from the header and store it in the LodePNGInfo. return value is error*/
+unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state,
+const unsigned char* in, size_t insize) {
+unsigned width, height;
+LodePNGInfo* info = &state->info_png;
+if(insize == 0 || in == 0) {
+CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/
+}
+if(insize < 33) {
+CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/
+}
+/*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/
+/* TODO: remove this. One should use a new LodePNGState for new sessions */
+lodepng_info_cleanup(info);
+lodepng_info_init(info);
+if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71
+|| in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) {
+CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/
+}
+if(lodepng_chunk_length(in + 8) != 13) {
+CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/
+}
+if(!lodepng_chunk_type_equals(in + 8, "IHDR")) {
+CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/
+}
+/*read the values given in the header*/
+width = lodepng_read32bitInt(&in[16]);
+height = lodepng_read32bitInt(&in[20]);
+/*TODO: remove the undocumented feature that allows to give null pointers to width or height*/
+if(w) *w = width;
+if(h) *h = height;
+info->color.bitdepth = in[24];
+info->color.colortype = (LodePNGColorType)in[25];
+info->compression_method = in[26];
+info->filter_method = in[27];
+info->interlace_method = in[28];
+/*errors returned only after the parsing so other values are still output*/
+/*error: invalid image size*/
+if(width == 0 || height == 0) CERROR_RETURN_ERROR(state->error, 93);
+/*error: invalid colortype or bitdepth combination*/
+state->error = checkColorValidity(info->color.colortype, info->color.bitdepth);
+if(state->error) return state->error;
+/*error: only compression method 0 is allowed in the specification*/
+if(info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32);
+/*error: only filter method 0 is allowed in the specification*/
+if(info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33);
+/*error: only interlace methods 0 and 1 exist in the specification*/
+if(info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34);
+if(!state->decoder.ignore_crc) {
+unsigned CRC = lodepng_read32bitInt(&in[29]);
+unsigned checksum = lodepng_crc32(&in[12], 17);
+if(CRC != checksum) {
+CERROR_RETURN_ERROR(state->error, 57); /*invalid CRC*/
+}
+}
+return state->error;
+}
+static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon,
+size_t bytewidth, unsigned char filterType, size_t length) {
+/*
+For PNG filter method 0
+unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte,
+the filter works byte per byte (bytewidth = 1)
+precon is the previous unfiltered scanline, recon the result, scanline the current one
+the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead
+recon and scanline MAY be the same memory address! precon must be disjoint.
+*/
+size_t i;
+switch(filterType) {
+case 0:
+for(i = 0; i != length; ++i) recon[i] = scanline[i];
+break;
+case 1: {
+size_t j = 0;
+for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
+for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + recon[j];
+break;
+}
+case 2:
+if(precon) {
+for(i = 0; i != length; ++i) recon[i] = scanline[i] + precon[i];
+} else {
+for(i = 0; i != length; ++i) recon[i] = scanline[i];
+}
+break;
+case 3:
+if(precon) {
+size_t j = 0;
+for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i] + (precon[i] >> 1u);
+/* Unroll independent paths of this predictor. A 6x and 8x version is also possible but that adds
+too much code. Whether this speeds up anything depends on compiler and settings. */
+if(bytewidth >= 4) {
+for(; i + 3 < length; i += 4, j += 4) {
+unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3];
+unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3];
+unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3];
+recon[i + 0] = s0 + ((r0 + p0) >> 1u);
+recon[i + 1] = s1 + ((r1 + p1) >> 1u);
+recon[i + 2] = s2 + ((r2 + p2) >> 1u);
+recon[i + 3] = s3 + ((r3 + p3) >> 1u);
+}
+} else if(bytewidth >= 3) {
+for(; i + 2 < length; i += 3, j += 3) {
+unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2];
+unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2];
+unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2];
+recon[i + 0] = s0 + ((r0 + p0) >> 1u);
+recon[i + 1] = s1 + ((r1 + p1) >> 1u);
+recon[i + 2] = s2 + ((r2 + p2) >> 1u);
+}
+} else if(bytewidth >= 2) {
+for(; i + 1 < length; i += 2, j += 2) {
+unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1];
+unsigned char r0 = recon[j + 0], r1 = recon[j + 1];
+unsigned char p0 = precon[i + 0], p1 = precon[i + 1];
+recon[i + 0] = s0 + ((r0 + p0) >> 1u);
+recon[i + 1] = s1 + ((r1 + p1) >> 1u);
+}
+}
+for(; i != length; ++i, ++j) recon[i] = scanline[i] + ((recon[j] + precon[i]) >> 1u);
+} else {
+size_t j = 0;
+for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
+for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + (recon[j] >> 1u);
+}
+break;
+case 4:
+if(precon) {
+/* Unroll independent paths of this predictor. Whether this speeds up
+anything depends on compiler and settings. */
+if(bytewidth == 8) {
+unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0;
+unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0;
+unsigned char a4, b4 = 0, c4, d4 = 0, a5, b5 = 0, c5, d5 = 0;
+unsigned char a6, b6 = 0, c6, d6 = 0, a7, b7 = 0, c7, d7 = 0;
+for(i = 0; i + 7 < length; i += 8) {
+c0 = b0; c1 = b1; c2 = b2; c3 = b3;
+c4 = b4; c5 = b5; c6 = b6; c7 = b7;
+b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; b3 = precon[i + 3];
+b4 = precon[i + 4]; b5 = precon[i + 5]; b6 = precon[i + 6]; b7 = precon[i + 7];
+a0 = d0; a1 = d1; a2 = d2; a3 = d3;
+a4 = d4; a5 = d5; a6 = d6; a7 = d7;
+d0 = scanline[i + 0] + paethPredictor(a0, b0, c0);
+d1 = scanline[i + 1] + paethPredictor(a1, b1, c1);
+d2 = scanline[i + 2] + paethPredictor(a2, b2, c2);
+d3 = scanline[i + 3] + paethPredictor(a3, b3, c3);
+d4 = scanline[i + 4] + paethPredictor(a4, b4, c4);
+d5 = scanline[i + 5] + paethPredictor(a5, b5, c5);
+d6 = scanline[i + 6] + paethPredictor(a6, b6, c6);
+d7 = scanline[i + 7] + paethPredictor(a7, b7, c7);
+recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; recon[i + 3] = d3;
+recon[i + 4] = d4; recon[i + 5] = d5; recon[i + 6] = d6; recon[i + 7] = d7;
+}
+} else if(bytewidth == 6) {
+unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0;
+unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0;
+unsigned char a4, b4 = 0, c4, d4 = 0, a5, b5 = 0, c5, d5 = 0;
+for(i = 0; i + 5 < length; i += 6) {
+c0 = b0; c1 = b1; c2 = b2;
+c3 = b3; c4 = b4; c5 = b5;
+b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2];
+b3 = precon[i + 3]; b4 = precon[i + 4]; b5 = precon[i + 5];
+a0 = d0; a1 = d1; a2 = d2;
+a3 = d3; a4 = d4; a5 = d5;
+d0 = scanline[i + 0] + paethPredictor(a0, b0, c0);
+d1 = scanline[i + 1] + paethPredictor(a1, b1, c1);
+d2 = scanline[i + 2] + paethPredictor(a2, b2, c2);
+d3 = scanline[i + 3] + paethPredictor(a3, b3, c3);
+d4 = scanline[i + 4] + paethPredictor(a4, b4, c4);
+d5 = scanline[i + 5] + paethPredictor(a5, b5, c5);
+recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2;
+recon[i + 3] = d3; recon[i + 4] = d4; recon[i + 5] = d5;
+}
+} else if(bytewidth == 4) {
+unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0;
+unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0;
+for(i = 0; i + 3 < length; i += 4) {
+c0 = b0; c1 = b1; c2 = b2; c3 = b3;
+b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; b3 = precon[i + 3];
+a0 = d0; a1 = d1; a2 = d2; a3 = d3;
+d0 = scanline[i + 0] + paethPredictor(a0, b0, c0);
+d1 = scanline[i + 1] + paethPredictor(a1, b1, c1);
+d2 = scanline[i + 2] + paethPredictor(a2, b2, c2);
+d3 = scanline[i + 3] + paethPredictor(a3, b3, c3);
+recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; recon[i + 3] = d3;
+}
+} else if(bytewidth == 3) {
+unsigned char a0, b0 = 0, c0, d0 = 0;
+unsigned char a1, b1 = 0, c1, d1 = 0;
+unsigned char a2, b2 = 0, c2, d2 = 0;
+for(i = 0; i + 2 < length; i += 3) {
+c0 = b0; c1 = b1; c2 = b2;
+b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2];
+a0 = d0; a1 = d1; a2 = d2;
+d0 = scanline[i + 0] + paethPredictor(a0, b0, c0);
+d1 = scanline[i + 1] + paethPredictor(a1, b1, c1);
+d2 = scanline[i + 2] + paethPredictor(a2, b2, c2);
+recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2;
+}
+} else if(bytewidth == 2) {
+unsigned char a0, b0 = 0, c0, d0 = 0;
+unsigned char a1, b1 = 0, c1, d1 = 0;
+for(i = 0; i + 1 < length; i += 2) {
+c0 = b0; c1 = b1;
+b0 = precon[i + 0];
+b1 = precon[i + 1];
+a0 = d0; a1 = d1;
+d0 = scanline[i + 0] + paethPredictor(a0, b0, c0);
+d1 = scanline[i + 1] + paethPredictor(a1, b1, c1);
+recon[i + 0] = d0;
+recon[i + 1] = d1;
+}
+} else if(bytewidth == 1) {
+unsigned char a, b = 0, c, d = 0;
+for(i = 0; i != length; ++i) {
+c = b;
+b = precon[i];
+a = d;
+d = scanline[i] + paethPredictor(a, b, c);
+recon[i] = d;
+}
+} else {
+/* Normally not a possible case, but this would handle it correctly */
+for(i = 0; i != bytewidth; ++i) {
+recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/
+}
+}
+/* finish any remaining bytes */
+for(; i != length; ++i) {
+recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth]));
+}
+} else {
+size_t j = 0;
+for(i = 0; i != bytewidth; ++i) {
+recon[i] = scanline[i];
+}
+for(i = bytewidth; i != length; ++i, ++j) {
+/*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/
+recon[i] = (scanline[i] + recon[j]);
+}
+}
+break;
+default: return 36; /*error: invalid filter type given*/
+}
+return 0;
+}
+static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
+/*
+For PNG filter method 0
+this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times)
+out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline
+w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
+in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
+*/
+unsigned y;
+unsigned char* prevline = 0;
+/*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
+size_t bytewidth = (bpp + 7u) / 8u;
+/*the width of a scanline in bytes, not including the filter type*/
+size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;
+for(y = 0; y < h; ++y) {
+size_t outindex = linebytes * y;
+size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+unsigned char filterType = in[inindex];
+CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes));
+prevline = &out[outindex];
+}
+return 0;
+}
+/*
+in: Adam7 interlaced image, with no padding bits between scanlines, but between
+reduced images so that each reduced image starts at a byte.
+out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h
+bpp: bits per pixel
+out has the following size in bits: w * h * bpp.
+in is possibly bigger due to padding bits between reduced images.
+out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation
+(because that's likely a little bit faster)
+NOTE: comments about padding bits are only relevant if bpp < 8
+*/
+static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
+unsigned passw[7], passh[7];
+size_t filter_passstart[8], padded_passstart[8], passstart[8];
+unsigned i;
+Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+if(bpp >= 8) {
+for(i = 0; i != 7; ++i) {
+unsigned x, y, b;
+size_t bytewidth = bpp / 8u;
+for(y = 0; y < passh[i]; ++y)
+for(x = 0; x < passw[i]; ++x) {
+size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth;
+size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w
++ ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth;
+for(b = 0; b < bytewidth; ++b) {
+out[pixeloutstart + b] = in[pixelinstart + b];
+}
+}
+}
+} else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
+for(i = 0; i != 7; ++i) {
+unsigned x, y, b;
+unsigned ilinebits = bpp * passw[i];
+unsigned olinebits = bpp * w;
+size_t obp, ibp; /*bit pointers (for out and in buffer)*/
+for(y = 0; y < passh[i]; ++y)
+for(x = 0; x < passw[i]; ++x) {
+ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
+obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp;
+for(b = 0; b < bpp; ++b) {
+unsigned char bit = readBitFromReversedStream(&ibp, in);
+setBitOfReversedStream(&obp, out, bit);
+}
+}
+}
+}
+}
+static void removePaddingBits(unsigned char* out, const unsigned char* in,
+size_t olinebits, size_t ilinebits, unsigned h) {
+/*
+After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need
+to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers
+for the Adam7 code, the color convert code and the output to the user.
+in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must
+have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits
+also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7
+only useful if (ilinebits - olinebits) is a value in the range 1..7
+*/
+unsigned y;
+size_t diff = ilinebits - olinebits;
+size_t ibp = 0, obp = 0; /*input and output bit pointers*/
+for(y = 0; y < h; ++y) {
+size_t x;
+for(x = 0; x < olinebits; ++x) {
+unsigned char bit = readBitFromReversedStream(&ibp, in);
+setBitOfReversedStream(&obp, out, bit);
+}
+ibp += diff;
+}
+}
+/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from
+the IDAT chunks (with filter index bytes and possible padding bits)
+return value is error*/
+static unsigned postProcessScanlines(unsigned char* out, unsigned char* in,
+unsigned w, unsigned h, const LodePNGInfo* info_png) {
+/*
+This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype.
+Steps:
+*) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8)
+*) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
+NOTE: the in buffer will be overwritten with intermediate data!
+*/
+unsigned bpp = lodepng_get_bpp(&info_png->color);
+if(bpp == 0) return 31; /*error: invalid colortype*/
+if(info_png->interlace_method == 0) {
+if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
+CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp));
+removePaddingBits(out, in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h);
+}
+/*we can immediately filter into the out buffer, no other steps needed*/
+else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp));
+} else /*interlace_method is 1 (Adam7)*/ {
+unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
+unsigned i;
+Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+for(i = 0; i != 7; ++i) {
+CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp));
+/*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline,
+move bytes instead of bits or move not at all*/
+if(bpp < 8) {
+/*remove padding bits in scanlines; after this there still may be padding
+bits between the different reduced images: each reduced image still starts nicely at a byte*/
+removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp,
+((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]);
+}
+}
+Adam7_deinterlace(out, in, w, h, bpp);
+}
+return 0;
+}
+static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) {
+unsigned pos = 0, i;
+color->palettesize = chunkLength / 3u;
+if(color->palettesize == 0 || color->palettesize > 256) return 38; /*error: palette too small or big*/
+lodepng_color_mode_alloc_palette(color);
+if(!color->palette && color->palettesize) {
+color->palettesize = 0;
+return 83; /*alloc fail*/
+}
+for(i = 0; i != color->palettesize; ++i) {
+color->palette[4 * i + 0] = data[pos++]; /*R*/
+color->palette[4 * i + 1] = data[pos++]; /*G*/
+color->palette[4 * i + 2] = data[pos++]; /*B*/
+color->palette[4 * i + 3] = 255; /*alpha*/
+}
+return 0; /* OK */
+}
+static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) {
+unsigned i;
+if(color->colortype == LCT_PALETTE) {
+/*error: more alpha values given than there are palette entries*/
+if(chunkLength > color->palettesize) return 39;
+for(i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i];
+} else if(color->colortype == LCT_GREY) {
+/*error: this chunk must be 2 bytes for grayscale image*/
+if(chunkLength != 2) return 30;
+color->key_defined = 1;
+color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1];
+} else if(color->colortype == LCT_RGB) {
+/*error: this chunk must be 6 bytes for RGB image*/
+if(chunkLength != 6) return 41;
+color->key_defined = 1;
+color->key_r = 256u * data[0] + data[1];
+color->key_g = 256u * data[2] + data[3];
+color->key_b = 256u * data[4] + data[5];
+}
+else return 42; /*error: tRNS chunk not allowed for other color models*/
+return 0; /* OK */
+}
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*background color chunk (bKGD)*/
+static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(info->color.colortype == LCT_PALETTE) {
+/*error: this chunk must be 1 byte for indexed color image*/
+if(chunkLength != 1) return 43;
+/*error: invalid palette index, or maybe this chunk appeared before PLTE*/
+if(data[0] >= info->color.palettesize) return 103;
+info->background_defined = 1;
+info->background_r = info->background_g = info->background_b = data[0];
+} else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) {
+/*error: this chunk must be 2 bytes for grayscale image*/
+if(chunkLength != 2) return 44;
+/*the values are truncated to bitdepth in the PNG file*/
+info->background_defined = 1;
+info->background_r = info->background_g = info->background_b = 256u * data[0] + data[1];
+} else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) {
+/*error: this chunk must be 6 bytes for grayscale image*/
+if(chunkLength != 6) return 45;
+/*the values are truncated to bitdepth in the PNG file*/
+info->background_defined = 1;
+info->background_r = 256u * data[0] + data[1];
+info->background_g = 256u * data[2] + data[3];
+info->background_b = 256u * data[4] + data[5];
+}
+return 0; /* OK */
+}
+/*text chunk (tEXt)*/
+static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+unsigned error = 0;
+char *key = 0, *str = 0;
+while(!error) /*not really a while loop, only used to break on error*/ {
+unsigned length, string2_begin;
+length = 0;
+while(length < chunkLength && data[length] != 0) ++length;
+/*even though it's not allowed by the standard, no error is thrown if
+there's no null termination char, if the text is empty*/
+if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+key = (char*)lodepng_malloc(length + 1);
+if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(key, data, length);
+key[length] = 0;
+string2_begin = length + 1; /*skip keyword null terminator*/
+length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin);
+str = (char*)lodepng_malloc(length + 1);
+if(!str) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(str, data + string2_begin, length);
+str[length] = 0;
+error = lodepng_add_text(info, key, str);
+break;
+}
+lodepng_free(key);
+lodepng_free(str);
+return error;
+}
+/*compressed text chunk (zTXt)*/
+static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
+const unsigned char* data, size_t chunkLength) {
+unsigned error = 0;
+/*copy the object to change parameters in it*/
+LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
+unsigned length, string2_begin;
+char *key = 0;
+unsigned char* str = 0;
+size_t size = 0;
+while(!error) /*not really a while loop, only used to break on error*/ {
+for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
+if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
+if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+key = (char*)lodepng_malloc(length + 1);
+if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(key, data, length);
+key[length] = 0;
+if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
+string2_begin = length + 2;
+if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
+length = (unsigned)chunkLength - string2_begin;
+zlibsettings.max_output_size = decoder->max_text_size;
+/*will fail if zlib error, e.g. if length is too small*/
+error = zlib_decompress(&str, &size, 0, &data[string2_begin],
+length, &zlibsettings);
+/*error: compressed text larger than  decoder->max_text_size*/
+if(error && size > zlibsettings.max_output_size) error = 112;
+if(error) break;
+error = lodepng_add_text_sized(info, key, (char*)str, size);
+break;
+}
+lodepng_free(key);
+lodepng_free(str);
+return error;
+}
+/*international text chunk (iTXt)*/
+static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
+const unsigned char* data, size_t chunkLength) {
+unsigned error = 0;
+unsigned i;
+/*copy the object to change parameters in it*/
+LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
+unsigned length, begin, compressed;
+char *key = 0, *langtag = 0, *transkey = 0;
+while(!error) /*not really a while loop, only used to break on error*/ {
+/*Quick check if the chunk length isn't too small. Even without check
+it'd still fail with other error checks below if it's too short. This just gives a different error code.*/
+if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/
+/*read the key*/
+for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
+if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/
+if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+key = (char*)lodepng_malloc(length + 1);
+if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(key, data, length);
+key[length] = 0;
+/*read the compression method*/
+compressed = data[length + 1];
+if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
+/*even though it's not allowed by the standard, no error is thrown if
+there's no null termination char, if the text is empty for the next 3 texts*/
+/*read the langtag*/
+begin = length + 3;
+length = 0;
+for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;
+langtag = (char*)lodepng_malloc(length + 1);
+if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(langtag, data + begin, length);
+langtag[length] = 0;
+/*read the transkey*/
+begin += length + 1;
+length = 0;
+for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;
+transkey = (char*)lodepng_malloc(length + 1);
+if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/
+lodepng_memcpy(transkey, data + begin, length);
+transkey[length] = 0;
+/*read the actual text*/
+begin += length + 1;
+length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin;
+if(compressed) {
+unsigned char* str = 0;
+size_t size = 0;
+zlibsettings.max_output_size = decoder->max_text_size;
+/*will fail if zlib error, e.g. if length is too small*/
+error = zlib_decompress(&str, &size, 0, &data[begin],
+length, &zlibsettings);
+/*error: compressed text larger than  decoder->max_text_size*/
+if(error && size > zlibsettings.max_output_size) error = 112;
+if(!error) error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)str, size);
+lodepng_free(str);
+} else {
+error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)(data + begin), length);
+}
+break;
+}
+lodepng_free(key);
+lodepng_free(langtag);
+lodepng_free(transkey);
+return error;
+}
+static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(chunkLength != 7) return 73; /*invalid tIME chunk size*/
+info->time_defined = 1;
+info->time.year = 256u * data[0] + data[1];
+info->time.month = data[2];
+info->time.day = data[3];
+info->time.hour = data[4];
+info->time.minute = data[5];
+info->time.second = data[6];
+return 0; /* OK */
+}
+static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/
+info->phys_defined = 1;
+info->phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];
+info->phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7];
+info->phys_unit = data[8];
+return 0; /* OK */
+}
+static unsigned readChunk_gAMA(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/
+info->gama_defined = 1;
+info->gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];
+return 0; /* OK */
+}
+static unsigned readChunk_cHRM(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/
+info->chrm_defined = 1;
+info->chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3];
+info->chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7];
+info->chrm_red_x   = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11];
+info->chrm_red_y   = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15];
+info->chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19];
+info->chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23];
+info->chrm_blue_x  = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27];
+info->chrm_blue_y  = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31];
+return 0; /* OK */
+}
+static unsigned readChunk_sRGB(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/
+info->srgb_defined = 1;
+info->srgb_intent = data[0];
+return 0; /* OK */
+}
+static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
+const unsigned char* data, size_t chunkLength) {
+unsigned error = 0;
+unsigned i;
+size_t size = 0;
+/*copy the object to change parameters in it*/
+LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
+unsigned length, string2_begin;
+info->iccp_defined = 1;
+if(info->iccp_name) lodepng_clear_icc(info);
+for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
+if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/
+if(length < 1 || length > 79) return 89; /*keyword too short or long*/
+info->iccp_name = (char*)lodepng_malloc(length + 1);
+if(!info->iccp_name) return 83; /*alloc fail*/
+info->iccp_name[length] = 0;
+for(i = 0; i != length; ++i) info->iccp_name[i] = (char)data[i];
+if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/
+string2_begin = length + 2;
+if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/
+length = (unsigned)chunkLength - string2_begin;
+zlibsettings.max_output_size = decoder->max_icc_size;
+error = zlib_decompress(&info->iccp_profile, &size, 0,
+&data[string2_begin],
+length, &zlibsettings);
+/*error: ICC profile larger than  decoder->max_icc_size*/
+if(error && size > zlibsettings.max_output_size) error = 113;
+info->iccp_profile_size = size;
+if(!error && !info->iccp_profile_size) error = 100; /*invalid ICC profile size*/
+return error;
+}
+/*significant bits chunk (sBIT)*/
+static unsigned readChunk_sBIT(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
+unsigned bitdepth = (info->color.colortype == LCT_PALETTE) ? 8 : info->color.bitdepth;
+if(info->color.colortype == LCT_GREY) {
+/*error: this chunk must be 1 bytes for grayscale image*/
+if(chunkLength != 1) return 114;
+if(data[0] == 0 || data[0] > bitdepth) return 115;
+info->sbit_defined = 1;
+info->sbit_r = info->sbit_g = info->sbit_b = data[0]; /*setting g and b is not required, but sensible*/
+} else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_PALETTE) {
+/*error: this chunk must be 3 bytes for RGB and palette image*/
+if(chunkLength != 3) return 114;
+if(data[0] == 0 || data[1] == 0 || data[2] == 0) return 115;
+if(data[0] > bitdepth || data[1] > bitdepth || data[2] > bitdepth) return 115;
+info->sbit_defined = 1;
+info->sbit_r = data[0];
+info->sbit_g = data[1];
+info->sbit_b = data[2];
+} else if(info->color.colortype == LCT_GREY_ALPHA) {
+/*error: this chunk must be 2 byte for grayscale with alpha image*/
+if(chunkLength != 2) return 114;
+if(data[0] == 0 || data[1] == 0) return 115;
+if(data[0] > bitdepth || data[1] > bitdepth) return 115;
+info->sbit_defined = 1;
+info->sbit_r = info->sbit_g = info->sbit_b = data[0]; /*setting g and b is not required, but sensible*/
+info->sbit_a = data[1];
+} else if(info->color.colortype == LCT_RGBA) {
+/*error: this chunk must be 4 bytes for grayscale image*/
+if(chunkLength != 4) return 114;
+if(data[0] == 0 || data[1] == 0 || data[2] == 0 || data[3] == 0) return 115;
+if(data[0] > bitdepth || data[1] > bitdepth || data[2] > bitdepth || data[3] > bitdepth) return 115;
+info->sbit_defined = 1;
+info->sbit_r = data[0];
+info->sbit_g = data[1];
+info->sbit_b = data[2];
+info->sbit_a = data[3];
+}
+return 0; /* OK */
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos,
+const unsigned char* in, size_t insize) {
+const unsigned char* chunk = in + pos;
+unsigned chunkLength;
+const unsigned char* data;
+unsigned unhandled = 0;
+unsigned error = 0;
+if(pos + 4 > insize) return 30;
+chunkLength = lodepng_chunk_length(chunk);
+if(chunkLength > 2147483647) return 63;
+data = lodepng_chunk_data_const(chunk);
+if(chunkLength + 12 > insize - pos) return 30;
+if(lodepng_chunk_type_equals(chunk, "PLTE")) {
+error = readChunk_PLTE(&state->info_png.color, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
+error = readChunk_tRNS(&state->info_png.color, data, chunkLength);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+} else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
+error = readChunk_bKGD(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
+error = readChunk_tEXt(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
+error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
+error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "tIME")) {
+error = readChunk_tIME(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
+error = readChunk_pHYs(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
+error = readChunk_gAMA(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
+error = readChunk_cHRM(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
+error = readChunk_sRGB(&state->info_png, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
+error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength);
+} else if(lodepng_chunk_type_equals(chunk, "sBIT")) {
+error = readChunk_sBIT(&state->info_png, data, chunkLength);
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} else {
+/* unhandled chunk is ok (is not an error) */
+unhandled = 1;
+}
+if(!error && !unhandled && !state->decoder.ignore_crc) {
+if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/
+}
+return error;
+}
+/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/
+static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h,
+LodePNGState* state,
+const unsigned char* in, size_t insize) {
+unsigned char IEND = 0;
+const unsigned char* chunk; /*points to beginning of next chunk*/
+unsigned char* idat; /*the data from idat chunks, zlib compressed*/
+size_t idatsize = 0;
+unsigned char* scanlines = 0;
+size_t scanlines_size = 0, expected_size = 0;
+size_t outsize = 0;
+/*for unknown chunk order*/
+unsigned unknown = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+/* safe output values in case error happens */
+*out = 0;
+*w = *h = 0;
+state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/
+if(state->error) return;
+if(lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) {
+CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/
+}
+/*the input filesize is a safe upper bound for the sum of idat chunks size*/
+idat = (unsigned char*)lodepng_malloc(insize);
+if(!idat) CERROR_RETURN(state->error, 83); /*alloc fail*/
+chunk = &in[33]; /*first byte of the first chunk after the header*/
+/*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk.
+IDAT data is put at the start of the in buffer*/
+while(!IEND && !state->error) {
+unsigned chunkLength;
+const unsigned char* data; /*the data in the chunk*/
+size_t pos = (size_t)(chunk - in);
+/*error: next chunk out of bounds of the in buffer*/
+if(chunk < in || pos + 12 > insize) {
+if(state->decoder.ignore_end) break; /*other errors may still happen though*/
+CERROR_BREAK(state->error, 30);
+}
+/*length of the data of the chunk, excluding the 12 bytes for length, chunk type and CRC*/
+chunkLength = lodepng_chunk_length(chunk);
+/*error: chunk length larger than the max PNG chunk size*/
+if(chunkLength > 2147483647) {
+if(state->decoder.ignore_end) break; /*other errors may still happen though*/
+CERROR_BREAK(state->error, 63);
+}
+if(pos + (size_t)chunkLength + 12 > insize || pos + (size_t)chunkLength + 12 < pos) {
+CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk (or int overflow)*/
+}
+data = lodepng_chunk_data_const(chunk);
+unknown = 0;
+/*IDAT chunk, containing compressed image data*/
+if(lodepng_chunk_type_equals(chunk, "IDAT")) {
+size_t newsize;
+if(lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95);
+if(newsize > insize) CERROR_BREAK(state->error, 95);
+lodepng_memcpy(idat + idatsize, data, chunkLength);
+idatsize += chunkLength;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+critical_pos = 3;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} else if(lodepng_chunk_type_equals(chunk, "IEND")) {
+/*IEND chunk*/
+IEND = 1;
+} else if(lodepng_chunk_type_equals(chunk, "PLTE")) {
+/*palette chunk (PLTE)*/
+state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength);
+if(state->error) break;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+critical_pos = 2;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
+/*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled
+in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that
+affects the alpha channel of pixels. */
+state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength);
+if(state->error) break;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*background color chunk (bKGD)*/
+} else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
+state->error = readChunk_bKGD(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
+/*text chunk (tEXt)*/
+if(state->decoder.read_text_chunks) {
+state->error = readChunk_tEXt(&state->info_png, data, chunkLength);
+if(state->error) break;
+}
+} else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
+/*compressed text chunk (zTXt)*/
+if(state->decoder.read_text_chunks) {
+state->error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength);
+if(state->error) break;
+}
+} else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
+/*international text chunk (iTXt)*/
+if(state->decoder.read_text_chunks) {
+state->error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength);
+if(state->error) break;
+}
+} else if(lodepng_chunk_type_equals(chunk, "tIME")) {
+state->error = readChunk_tIME(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
+state->error = readChunk_pHYs(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
+state->error = readChunk_gAMA(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
+state->error = readChunk_cHRM(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
+state->error = readChunk_sRGB(&state->info_png, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
+state->error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength);
+if(state->error) break;
+} else if(lodepng_chunk_type_equals(chunk, "sBIT")) {
+state->error = readChunk_sBIT(&state->info_png, data, chunkLength);
+if(state->error) break;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} else /*it's not an implemented chunk type, so ignore it: skip over the data*/ {
+/*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/
+if(!state->decoder.ignore_critical && !lodepng_chunk_ancillary(chunk)) {
+CERROR_BREAK(state->error, 69);
+}
+unknown = 1;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+if(state->decoder.remember_unknown_chunks) {
+state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1],
+&state->info_png.unknown_chunks_size[critical_pos - 1], chunk);
+if(state->error) break;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/ {
+if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/
+}
+if(!IEND) chunk = lodepng_chunk_next_const(chunk, in + insize);
+}
+if(!state->error && state->info_png.color.colortype == LCT_PALETTE && !state->info_png.color.palette) {
+state->error = 106; /* error: PNG file must have PLTE chunk if color type is palette */
+}
+if(!state->error) {
+/*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation.
+If the decompressed size does not match the prediction, the image must be corrupt.*/
+if(state->info_png.interlace_method == 0) {
+size_t bpp = lodepng_get_bpp(&state->info_png.color);
+expected_size = lodepng_get_raw_size_idat(*w, *h, bpp);
+} else {
+size_t bpp = lodepng_get_bpp(&state->info_png.color);
+/*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/
+expected_size = 0;
+expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp);
+if(*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp);
+expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp);
+if(*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp);
+expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp);
+if(*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp);
+expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp);
+}
+state->error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state->decoder.zlibsettings);
+}
+if(!state->error && scanlines_size != expected_size) state->error = 91; /*decompressed size doesn't match prediction*/
+lodepng_free(idat);
+if(!state->error) {
+outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color);
+*out = (unsigned char*)lodepng_malloc(outsize);
+if(!*out) state->error = 83; /*alloc fail*/
+}
+if(!state->error) {
+lodepng_memset(*out, 0, outsize);
+state->error = postProcessScanlines(*out, scanlines, *w, *h, &state->info_png);
+}
+lodepng_free(scanlines);
+}
+unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h,
+LodePNGState* state,
+const unsigned char* in, size_t insize) {
+*out = 0;
+decodeGeneric(out, w, h, state, in, insize);
+if(state->error) return state->error;
+if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) {
+/*same color type, no copying or converting of data needed*/
+/*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype
+the raw image has to the end user*/
+if(!state->decoder.color_convert) {
+state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color);
+if(state->error) return state->error;
+}
+} else { /*color conversion needed*/
+unsigned char* data = *out;
+size_t outsize;
+/*TODO: check if this works according to the statement in the documentation: "The converter can convert
+from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/
+if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA)
+&& !(state->info_raw.bitdepth == 8)) {
+return 56; /*unsupported color mode conversion*/
+}
+outsize = lodepng_get_raw_size(*w, *h, &state->info_raw);
+*out = (unsigned char*)lodepng_malloc(outsize);
+if(!(*out)) {
+state->error = 83; /*alloc fail*/
+}
+else state->error = lodepng_convert(*out, data, &state->info_raw,
+&state->info_png.color, *w, *h);
+lodepng_free(data);
+}
+return state->error;
+}
+unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in,
+size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
+unsigned error;
+LodePNGState state;
+lodepng_state_init(&state);
+state.info_raw.colortype = colortype;
+state.info_raw.bitdepth = bitdepth;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*disable reading things that this function doesn't output*/
+state.decoder.read_text_chunks = 0;
+state.decoder.remember_unknown_chunks = 0;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+error = lodepng_decode(out, w, h, &state, in, insize);
+lodepng_state_cleanup(&state);
+return error;
+}
+unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) {
+return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8);
+}
+unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) {
+return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8);
+}
+#ifdef LODEPNG_COMPILE_DISK
+unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename,
+LodePNGColorType colortype, unsigned bitdepth) {
+unsigned char* buffer = 0;
+size_t buffersize;
+unsigned error;
+/* safe output values in case error happens */
+*out = 0;
+*w = *h = 0;
+error = lodepng_load_file(&buffer, &buffersize, filename);
+if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth);
+lodepng_free(buffer);
+return error;
+}
+unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) {
+return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8);
+}
+unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) {
+return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8);
+}
+#endif /*LODEPNG_COMPILE_DISK*/
+void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) {
+settings->color_convert = 1;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+settings->read_text_chunks = 1;
+settings->remember_unknown_chunks = 0;
+settings->max_text_size = 16777216;
+settings->max_icc_size = 16777216; /* 16MB is much more than enough for any reasonable ICC profile */
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+settings->ignore_crc = 0;
+settings->ignore_critical = 0;
+settings->ignore_end = 0;
+lodepng_decompress_settings_init(&settings->zlibsettings);
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER)
+void lodepng_state_init(LodePNGState* state) {
+#ifdef LODEPNG_COMPILE_DECODER
+lodepng_decoder_settings_init(&state->decoder);
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+lodepng_encoder_settings_init(&state->encoder);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+lodepng_color_mode_init(&state->info_raw);
+lodepng_info_init(&state->info_png);
+state->error = 1;
+}
+void lodepng_state_cleanup(LodePNGState* state) {
+lodepng_color_mode_cleanup(&state->info_raw);
+lodepng_info_cleanup(&state->info_png);
+}
+void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source) {
+lodepng_state_cleanup(dest);
+*dest = *source;
+lodepng_color_mode_init(&dest->info_raw);
+lodepng_info_init(&dest->info_png);
+dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return;
+dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); if(dest->error) return;
+}
+#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */
+#ifdef LODEPNG_COMPILE_ENCODER
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG Encoder                                                            / */
+/* ////////////////////////////////////////////////////////////////////////// */
+static unsigned writeSignature(ucvector* out) {
+size_t pos = out->size;
+const unsigned char signature[] = {137, 80, 78, 71, 13, 10, 26, 10};
+/*8 bytes PNG signature, aka the magic bytes*/
+if(!ucvector_resize(out, out->size + 8)) return 83; /*alloc fail*/
+lodepng_memcpy(out->data + pos, signature, 8);
+return 0;
+}
+static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) {
+unsigned char *chunk, *data;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 13, "IHDR"));
+data = chunk + 8;
+lodepng_set32bitInt(data + 0, w); /*width*/
+lodepng_set32bitInt(data + 4, h); /*height*/
+data[8] = (unsigned char)bitdepth; /*bit depth*/
+data[9] = (unsigned char)colortype; /*color type*/
+data[10] = 0; /*compression method*/
+data[11] = 0; /*filter method*/
+data[12] = interlace_method; /*interlace method*/
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+/* only adds the chunk if needed (there is a key or palette with alpha) */
+static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) {
+unsigned char* chunk;
+size_t i, j = 8;
+if(info->palettesize == 0 || info->palettesize > 256) {
+return 68; /*invalid palette size, it is only allowed to be 1-256*/
+}
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, info->palettesize * 3, "PLTE"));
+for(i = 0; i != info->palettesize; ++i) {
+/*add all channels except alpha channel*/
+chunk[j++] = info->palette[i * 4 + 0];
+chunk[j++] = info->palette[i * 4 + 1];
+chunk[j++] = info->palette[i * 4 + 2];
+}
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) {
+unsigned char* chunk = 0;
+if(info->colortype == LCT_PALETTE) {
+size_t i, amount = info->palettesize;
+/*the tail of palette values that all have 255 as alpha, does not have to be encoded*/
+for(i = info->palettesize; i != 0; --i) {
+if(info->palette[4 * (i - 1) + 3] != 255) break;
+--amount;
+}
+if(amount) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, amount, "tRNS"));
+/*add the alpha channel values from the palette*/
+for(i = 0; i != amount; ++i) chunk[8 + i] = info->palette[4 * i + 3];
+}
+} else if(info->colortype == LCT_GREY) {
+if(info->key_defined) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "tRNS"));
+chunk[8] = (unsigned char)(info->key_r >> 8);
+chunk[9] = (unsigned char)(info->key_r & 255);
+}
+} else if(info->colortype == LCT_RGB) {
+if(info->key_defined) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "tRNS"));
+chunk[8] = (unsigned char)(info->key_r >> 8);
+chunk[9] = (unsigned char)(info->key_r & 255);
+chunk[10] = (unsigned char)(info->key_g >> 8);
+chunk[11] = (unsigned char)(info->key_g & 255);
+chunk[12] = (unsigned char)(info->key_b >> 8);
+chunk[13] = (unsigned char)(info->key_b & 255);
+}
+}
+if(chunk) lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize,
+LodePNGCompressSettings* zlibsettings) {
+unsigned error = 0;
+unsigned char* zlib = 0;
+size_t zlibsize = 0;
+error = zlib_compress(&zlib, &zlibsize, data, datasize, zlibsettings);
+if(!error) {
+error = lodepng_chunk_createv(out, zlibsize, "IDAT", zlib);
+}
+lodepng_free(zlib);
+return error;
+}
+static unsigned addChunk_IEND(ucvector* out) {
+return lodepng_chunk_createv(out, 0, "IEND", 0);
+}
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) {
+unsigned char* chunk = 0;
+size_t keysize = lodepng_strlen(keyword), textsize = lodepng_strlen(textstring);
+size_t size = keysize + 1 + textsize;
+if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, size, "tEXt"));
+lodepng_memcpy(chunk + 8, keyword, keysize);
+chunk[8 + keysize] = 0; /*null termination char*/
+lodepng_memcpy(chunk + 9 + keysize, textstring, textsize);
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring,
+LodePNGCompressSettings* zlibsettings) {
+unsigned error = 0;
+unsigned char* chunk = 0;
+unsigned char* compressed = 0;
+size_t compressedsize = 0;
+size_t textsize = lodepng_strlen(textstring);
+size_t keysize = lodepng_strlen(keyword);
+if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
+error = zlib_compress(&compressed, &compressedsize,
+(const unsigned char*)textstring, textsize, zlibsettings);
+if(!error) {
+size_t size = keysize + 2 + compressedsize;
+error = lodepng_chunk_init(&chunk, out, size, "zTXt");
+}
+if(!error) {
+lodepng_memcpy(chunk + 8, keyword, keysize);
+chunk[8 + keysize] = 0; /*null termination char*/
+chunk[9 + keysize] = 0; /*compression method: 0*/
+lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
+lodepng_chunk_generate_crc(chunk);
+}
+lodepng_free(compressed);
+return error;
+}
+static unsigned addChunk_iTXt(ucvector* out, unsigned compress, const char* keyword, const char* langtag,
+const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings) {
+unsigned error = 0;
+unsigned char* chunk = 0;
+unsigned char* compressed = 0;
+size_t compressedsize = 0;
+size_t textsize = lodepng_strlen(textstring);
+size_t keysize = lodepng_strlen(keyword), langsize = lodepng_strlen(langtag), transsize = lodepng_strlen(transkey);
+if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
+if(compress) {
+error = zlib_compress(&compressed, &compressedsize,
+(const unsigned char*)textstring, textsize, zlibsettings);
+}
+if(!error) {
+size_t size = keysize + 3 + langsize + 1 + transsize + 1 + (compress ? compressedsize : textsize);
+error = lodepng_chunk_init(&chunk, out, size, "iTXt");
+}
+if(!error) {
+size_t pos = 8;
+lodepng_memcpy(chunk + pos, keyword, keysize);
+pos += keysize;
+chunk[pos++] = 0; /*null termination char*/
+chunk[pos++] = (compress ? 1 : 0); /*compression flag*/
+chunk[pos++] = 0; /*compression method: 0*/
+lodepng_memcpy(chunk + pos, langtag, langsize);
+pos += langsize;
+chunk[pos++] = 0; /*null termination char*/
+lodepng_memcpy(chunk + pos, transkey, transsize);
+pos += transsize;
+chunk[pos++] = 0; /*null termination char*/
+if(compress) {
+lodepng_memcpy(chunk + pos, compressed, compressedsize);
+} else {
+lodepng_memcpy(chunk + pos, textstring, textsize);
+}
+lodepng_chunk_generate_crc(chunk);
+}
+lodepng_free(compressed);
+return error;
+}
+static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) {
+unsigned char* chunk = 0;
+if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "bKGD"));
+chunk[8] = (unsigned char)(info->background_r >> 8);
+chunk[9] = (unsigned char)(info->background_r & 255);
+} else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "bKGD"));
+chunk[8] = (unsigned char)(info->background_r >> 8);
+chunk[9] = (unsigned char)(info->background_r & 255);
+chunk[10] = (unsigned char)(info->background_g >> 8);
+chunk[11] = (unsigned char)(info->background_g & 255);
+chunk[12] = (unsigned char)(info->background_b >> 8);
+chunk[13] = (unsigned char)(info->background_b & 255);
+} else if(info->color.colortype == LCT_PALETTE) {
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "bKGD"));
+chunk[8] = (unsigned char)(info->background_r & 255); /*palette index*/
+}
+if(chunk) lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) {
+unsigned char* chunk;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 7, "tIME"));
+chunk[8] = (unsigned char)(time->year >> 8);
+chunk[9] = (unsigned char)(time->year & 255);
+chunk[10] = (unsigned char)time->month;
+chunk[11] = (unsigned char)time->day;
+chunk[12] = (unsigned char)time->hour;
+chunk[13] = (unsigned char)time->minute;
+chunk[14] = (unsigned char)time->second;
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) {
+unsigned char* chunk;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 9, "pHYs"));
+lodepng_set32bitInt(chunk + 8, info->phys_x);
+lodepng_set32bitInt(chunk + 12, info->phys_y);
+chunk[16] = info->phys_unit;
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) {
+unsigned char* chunk;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "gAMA"));
+lodepng_set32bitInt(chunk + 8, info->gama_gamma);
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) {
+unsigned char* chunk;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 32, "cHRM"));
+lodepng_set32bitInt(chunk + 8, info->chrm_white_x);
+lodepng_set32bitInt(chunk + 12, info->chrm_white_y);
+lodepng_set32bitInt(chunk + 16, info->chrm_red_x);
+lodepng_set32bitInt(chunk + 20, info->chrm_red_y);
+lodepng_set32bitInt(chunk + 24, info->chrm_green_x);
+lodepng_set32bitInt(chunk + 28, info->chrm_green_y);
+lodepng_set32bitInt(chunk + 32, info->chrm_blue_x);
+lodepng_set32bitInt(chunk + 36, info->chrm_blue_y);
+lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) {
+unsigned char data = info->srgb_intent;
+return lodepng_chunk_createv(out, 1, "sRGB", &data);
+}
+static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, LodePNGCompressSettings* zlibsettings) {
+unsigned error = 0;
+unsigned char* chunk = 0;
+unsigned char* compressed = 0;
+size_t compressedsize = 0;
+size_t keysize = lodepng_strlen(info->iccp_name);
+if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
+error = zlib_compress(&compressed, &compressedsize,
+info->iccp_profile, info->iccp_profile_size, zlibsettings);
+if(!error) {
+size_t size = keysize + 2 + compressedsize;
+error = lodepng_chunk_init(&chunk, out, size, "iCCP");
+}
+if(!error) {
+lodepng_memcpy(chunk + 8, info->iccp_name, keysize);
+chunk[8 + keysize] = 0; /*null termination char*/
+chunk[9 + keysize] = 0; /*compression method: 0*/
+lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
+lodepng_chunk_generate_crc(chunk);
+}
+lodepng_free(compressed);
+return error;
+}
+static unsigned addChunk_sBIT(ucvector* out, const LodePNGInfo* info) {
+unsigned bitdepth = (info->color.colortype == LCT_PALETTE) ? 8 : info->color.bitdepth;
+unsigned char* chunk = 0;
+if(info->color.colortype == LCT_GREY) {
+if(info->sbit_r == 0 || info->sbit_r > bitdepth) return 115;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "sBIT"));
+chunk[8] = info->sbit_r;
+} else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_PALETTE) {
+if(info->sbit_r == 0 || info->sbit_g == 0 || info->sbit_b == 0) return 115;
+if(info->sbit_r > bitdepth || info->sbit_g > bitdepth || info->sbit_b > bitdepth) return 115;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 3, "sBIT"));
+chunk[8] = info->sbit_r;
+chunk[9] = info->sbit_g;
+chunk[10] = info->sbit_b;
+} else if(info->color.colortype == LCT_GREY_ALPHA) {
+if(info->sbit_r == 0 || info->sbit_a == 0) return 115;
+if(info->sbit_r > bitdepth || info->sbit_a > bitdepth) return 115;
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "sBIT"));
+chunk[8] = info->sbit_r;
+chunk[9] = info->sbit_a;
+} else if(info->color.colortype == LCT_RGBA) {
+if(info->sbit_r == 0 || info->sbit_g == 0 || info->sbit_b == 0 || info->sbit_a == 0 ||
+info->sbit_r > bitdepth || info->sbit_g > bitdepth ||
+info->sbit_b > bitdepth || info->sbit_a > bitdepth) {
+return 115;
+}
+CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "sBIT"));
+chunk[8] = info->sbit_r;
+chunk[9] = info->sbit_g;
+chunk[10] = info->sbit_b;
+chunk[11] = info->sbit_a;
+}
+if(chunk) lodepng_chunk_generate_crc(chunk);
+return 0;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline,
+size_t length, size_t bytewidth, unsigned char filterType) {
+size_t i;
+switch(filterType) {
+case 0: /*None*/
+for(i = 0; i != length; ++i) out[i] = scanline[i];
+break;
+case 1: /*Sub*/
+for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
+for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth];
+break;
+case 2: /*Up*/
+if(prevline) {
+for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i];
+} else {
+for(i = 0; i != length; ++i) out[i] = scanline[i];
+}
+break;
+case 3: /*Average*/
+if(prevline) {
+for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1);
+for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1);
+} else {
+for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
+for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1);
+}
+break;
+case 4: /*Paeth*/
+if(prevline) {
+/*paethPredictor(0, prevline[i], 0) is always prevline[i]*/
+for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]);
+for(i = bytewidth; i < length; ++i) {
+out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth]));
+}
+} else {
+for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
+/*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/
+for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]);
+}
+break;
+default: return; /*invalid filter type given*/
+}
+}
+/* integer binary logarithm, max return value is 31 */
+static size_t ilog2(size_t i) {
+size_t result = 0;
+if(i >= 65536) { result += 16; i >>= 16; }
+if(i >= 256) { result += 8; i >>= 8; }
+if(i >= 16) { result += 4; i >>= 4; }
+if(i >= 4) { result += 2; i >>= 2; }
+if(i >= 2) { result += 1; /*i >>= 1;*/ }
+return result;
+}
+/* integer approximation for i * log2(i), helper function for LFS_ENTROPY */
+static size_t ilog2i(size_t i) {
+size_t l;
+if(i == 0) return 0;
+l = ilog2(i);
+/* approximate i*log2(i): l is integer logarithm, ((i - (1u << l)) << 1u)
+linearly approximates the missing fractional part multiplied by i */
+return i * l + ((i - (1u << l)) << 1u);
+}
+static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h,
+const LodePNGColorMode* color, const LodePNGEncoderSettings* settings) {
+/*
+For PNG filter method 0
+out must be a buffer with as size: h + (w * h * bpp + 7u) / 8u, because there are
+the scanlines with 1 extra byte per scanline
+*/
+unsigned bpp = lodepng_get_bpp(color);
+/*the width of a scanline in bytes, not including the filter type*/
+size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;
+/*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
+size_t bytewidth = (bpp + 7u) / 8u;
+const unsigned char* prevline = 0;
+unsigned x, y;
+unsigned error = 0;
+LodePNGFilterStrategy strategy = settings->filter_strategy;
+/*
+There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard:
+*  If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e.
+use fixed filtering, with the filter None).
+* (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is
+not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply
+all five filters and select the filter that produces the smallest sum of absolute values per row.
+This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true.
+If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed,
+but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum
+heuristic is used.
+*/
+if(settings->filter_palette_zero &&
+(color->colortype == LCT_PALETTE || color->bitdepth < 8)) strategy = LFS_ZERO;
+if(bpp == 0) return 31; /*error: invalid color type*/
+if(strategy >= LFS_ZERO && strategy <= LFS_FOUR) {
+unsigned char type = (unsigned char)strategy;
+for(y = 0; y != h; ++y) {
+size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+size_t inindex = linebytes * y;
+out[outindex] = type; /*filter type byte*/
+filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
+prevline = &in[inindex];
+}
+} else if(strategy == LFS_MINSUM) {
+/*adaptive filtering*/
+unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
+size_t smallest = 0;
+unsigned char type, bestType = 0;
+for(type = 0; type != 5; ++type) {
+attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
+if(!attempt[type]) error = 83; /*alloc fail*/
+}
+if(!error) {
+for(y = 0; y != h; ++y) {
+/*try the 5 filter types*/
+for(type = 0; type != 5; ++type) {
+size_t sum = 0;
+filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
+/*calculate the sum of the result*/
+if(type == 0) {
+for(x = 0; x != linebytes; ++x) sum += (unsigned char)(attempt[type][x]);
+} else {
+for(x = 0; x != linebytes; ++x) {
+/*For differences, each byte should be treated as signed, values above 127 are negative
+(converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there.
+This means filtertype 0 is almost never chosen, but that is justified.*/
+unsigned char s = attempt[type][x];
+sum += s < 128 ? s : (255U - s);
+}
+}
+/*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
+if(type == 0 || sum < smallest) {
+bestType = type;
+smallest = sum;
+}
+}
+prevline = &in[y * linebytes];
+/*now fill the out values*/
+out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
+}
+}
+for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
+} else if(strategy == LFS_ENTROPY) {
+unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
+size_t bestSum = 0;
+unsigned type, bestType = 0;
+unsigned count[256];
+for(type = 0; type != 5; ++type) {
+attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
+if(!attempt[type]) error = 83; /*alloc fail*/
+}
+if(!error) {
+for(y = 0; y != h; ++y) {
+/*try the 5 filter types*/
+for(type = 0; type != 5; ++type) {
+size_t sum = 0;
+filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
+lodepng_memset(count, 0, 256 * sizeof(*count));
+for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]];
+++count[type]; /*the filter type itself is part of the scanline*/
+for(x = 0; x != 256; ++x) {
+sum += ilog2i(count[x]);
+}
+/*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
+if(type == 0 || sum > bestSum) {
+bestType = type;
+bestSum = sum;
+}
+}
+prevline = &in[y * linebytes];
+/*now fill the out values*/
+out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
+}
+}
+for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
+} else if(strategy == LFS_PREDEFINED) {
+for(y = 0; y != h; ++y) {
+size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+size_t inindex = linebytes * y;
+unsigned char type = settings->predefined_filters[y];
+out[outindex] = type; /*filter type byte*/
+filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
+prevline = &in[inindex];
+}
+} else if(strategy == LFS_BRUTE_FORCE) {
+/*brute force filter chooser.
+deflate the scanline after every filter attempt to see which one deflates best.
+This is very slow and gives only slightly smaller, sometimes even larger, result*/
+size_t size[5];
+unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
+size_t smallest = 0;
+unsigned type = 0, bestType = 0;
+unsigned char* dummy;
+LodePNGCompressSettings zlibsettings;
+lodepng_memcpy(&zlibsettings, &settings->zlibsettings, sizeof(LodePNGCompressSettings));
+/*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose,
+to simulate the true case where the tree is the same for the whole image. Sometimes it gives
+better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare
+cases better compression. It does make this a bit less slow, so it's worth doing this.*/
+zlibsettings.btype = 1;
+/*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG
+images only, so disable it*/
+zlibsettings.custom_zlib = 0;
+zlibsettings.custom_deflate = 0;
+for(type = 0; type != 5; ++type) {
+attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
+if(!attempt[type]) error = 83; /*alloc fail*/
+}
+if(!error) {
+for(y = 0; y != h; ++y) /*try the 5 filter types*/ {
+for(type = 0; type != 5; ++type) {
+unsigned testsize = (unsigned)linebytes;
+/*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/
+filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
+size[type] = 0;
+dummy = 0;
+zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings);
+lodepng_free(dummy);
+/*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/
+if(type == 0 || size[type] < smallest) {
+bestType = type;
+smallest = size[type];
+}
+}
+prevline = &in[y * linebytes];
+out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
+}
+}
+for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
+}
+else return 88; /* unknown filter strategy */
+return error;
+}
+static void addPaddingBits(unsigned char* out, const unsigned char* in,
+size_t olinebits, size_t ilinebits, unsigned h) {
+/*The opposite of the removePaddingBits function
+olinebits must be >= ilinebits*/
+unsigned y;
+size_t diff = olinebits - ilinebits;
+size_t obp = 0, ibp = 0; /*bit pointers*/
+for(y = 0; y != h; ++y) {
+size_t x;
+for(x = 0; x < ilinebits; ++x) {
+unsigned char bit = readBitFromReversedStream(&ibp, in);
+setBitOfReversedStream(&obp, out, bit);
+}
+/*obp += diff; --> no, fill in some value in the padding bits too, to avoid
+"Use of uninitialised value of size ###" warning from valgrind*/
+for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0);
+}
+}
+/*
+in: non-interlaced image with size w*h
+out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with
+no padding bits between scanlines, but between reduced images so that each
+reduced image starts at a byte.
+bpp: bits per pixel
+there are no padding bits, not between scanlines, not between reduced images
+in has the following size in bits: w * h * bpp.
+out is possibly bigger due to padding bits between reduced images
+NOTE: comments about padding bits are only relevant if bpp < 8
+*/
+static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
+unsigned passw[7], passh[7];
+size_t filter_passstart[8], padded_passstart[8], passstart[8];
+unsigned i;
+Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+if(bpp >= 8) {
+for(i = 0; i != 7; ++i) {
+unsigned x, y, b;
+size_t bytewidth = bpp / 8u;
+for(y = 0; y < passh[i]; ++y)
+for(x = 0; x < passw[i]; ++x) {
+size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
+size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth;
+for(b = 0; b < bytewidth; ++b) {
+out[pixeloutstart + b] = in[pixelinstart + b];
+}
+}
+}
+} else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
+for(i = 0; i != 7; ++i) {
+unsigned x, y, b;
+unsigned ilinebits = bpp * passw[i];
+unsigned olinebits = bpp * w;
+size_t obp, ibp; /*bit pointers (for out and in buffer)*/
+for(y = 0; y < passh[i]; ++y)
+for(x = 0; x < passw[i]; ++x) {
+ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
+obp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
+for(b = 0; b < bpp; ++b) {
+unsigned char bit = readBitFromReversedStream(&ibp, in);
+setBitOfReversedStream(&obp, out, bit);
+}
+}
+}
+}
+}
+/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image.
+return value is error**/
+static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in,
+unsigned w, unsigned h,
+const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings) {
+/*
+This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps:
+*) if no Adam7: 1) add padding bits (= possible extra bits per scanline if bpp < 8) 2) filter
+*) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter
+*/
+unsigned bpp = lodepng_get_bpp(&info_png->color);
+unsigned error = 0;
+if(info_png->interlace_method == 0) {
+*outsize = h + (h * ((w * bpp + 7u) / 8u)); /*image size plus an extra byte per scanline + possible padding bits*/
+*out = (unsigned char*)lodepng_malloc(*outsize);
+if(!(*out) && (*outsize)) error = 83; /*alloc fail*/
+if(!error) {
+/*non multiple of 8 bits per scanline, padding bits needed per scanline*/
+if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
+unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7u) / 8u));
+if(!padded) error = 83; /*alloc fail*/
+if(!error) {
+addPaddingBits(padded, in, ((w * bpp + 7u) / 8u) * 8u, w * bpp, h);
+error = filter(*out, padded, w, h, &info_png->color, settings);
+}
+lodepng_free(padded);
+} else {
+/*we can immediately filter into the out buffer, no other steps needed*/
+error = filter(*out, in, w, h, &info_png->color, settings);
+}
+}
+} else /*interlace_method is 1 (Adam7)*/ {
+unsigned passw[7], passh[7];
+size_t filter_passstart[8], padded_passstart[8], passstart[8];
+unsigned char* adam7;
+Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+*outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/
+*out = (unsigned char*)lodepng_malloc(*outsize);
+if(!(*out)) error = 83; /*alloc fail*/
+adam7 = (unsigned char*)lodepng_malloc(passstart[7]);
+if(!adam7 && passstart[7]) error = 83; /*alloc fail*/
+if(!error) {
+unsigned i;
+Adam7_interlace(adam7, in, w, h, bpp);
+for(i = 0; i != 7; ++i) {
+if(bpp < 8) {
+unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]);
+if(!padded) ERROR_BREAK(83); /*alloc fail*/
+addPaddingBits(padded, &adam7[passstart[i]],
+((passw[i] * bpp + 7u) / 8u) * 8u, passw[i] * bpp, passh[i]);
+error = filter(&(*out)[filter_passstart[i]], padded,
+passw[i], passh[i], &info_png->color, settings);
+lodepng_free(padded);
+} else {
+error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]],
+passw[i], passh[i], &info_png->color, settings);
+}
+if(error) break;
+}
+}
+lodepng_free(adam7);
+}
+return error;
+}
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+static unsigned addUnknownChunks(ucvector* out, unsigned char* data, size_t datasize) {
+unsigned char* inchunk = data;
+while((size_t)(inchunk - data) < datasize) {
+CERROR_TRY_RETURN(lodepng_chunk_append(&out->data, &out->size, inchunk));
+out->allocsize = out->size; /*fix the allocsize again*/
+inchunk = lodepng_chunk_next(inchunk, data + datasize);
+}
+return 0;
+}
+static unsigned isGrayICCProfile(const unsigned char* profile, unsigned size) {
+/*
+It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19
+are "RGB ". We do not perform any full parsing of the ICC profile here, other
+than check those 4 bytes to grayscale profile. Other than that, validity of
+the profile is not checked. This is needed only because the PNG specification
+requires using a non-gray color model if there is an ICC profile with "RGB "
+(sadly limiting compression opportunities if the input data is grayscale RGB
+data), and requires using a gray color model if it is "GRAY".
+*/
+if(size < 20) return 0;
+return profile[16] == 'G' &&  profile[17] == 'R' &&  profile[18] == 'A' &&  profile[19] == 'Y';
+}
+static unsigned isRGBICCProfile(const unsigned char* profile, unsigned size) {
+/* See comment in isGrayICCProfile*/
+if(size < 20) return 0;
+return profile[16] == 'R' &&  profile[17] == 'G' &&  profile[18] == 'B' &&  profile[19] == ' ';
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+unsigned lodepng_encode(unsigned char** out, size_t* outsize,
+const unsigned char* image, unsigned w, unsigned h,
+LodePNGState* state) {
+unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/
+size_t datasize = 0;
+ucvector outv = ucvector_init(NULL, 0);
+LodePNGInfo info;
+const LodePNGInfo* info_png = &state->info_png;
+LodePNGColorMode auto_color;
+lodepng_info_init(&info);
+lodepng_color_mode_init(&auto_color);
+/*provide some proper output values if error will happen*/
+*out = 0;
+*outsize = 0;
+state->error = 0;
+/*check input values validity*/
+if((info_png->color.colortype == LCT_PALETTE || state->encoder.force_palette)
+&& (info_png->color.palettesize == 0 || info_png->color.palettesize > 256)) {
+/*this error is returned even if auto_convert is enabled and thus encoder could
+generate the palette by itself: while allowing this could be possible in theory,
+it may complicate the code or edge cases, and always requiring to give a palette
+when setting this color type is a simpler contract*/
+state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/
+goto cleanup;
+}
+if(state->encoder.zlibsettings.btype > 2) {
+state->error = 61; /*error: invalid btype*/
+goto cleanup;
+}
+if(info_png->interlace_method > 1) {
+state->error = 71; /*error: invalid interlace mode*/
+goto cleanup;
+}
+state->error = checkColorValidity(info_png->color.colortype, info_png->color.bitdepth);
+if(state->error) goto cleanup; /*error: invalid color type given*/
+state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth);
+if(state->error) goto cleanup; /*error: invalid color type given*/
+/* color convert and compute scanline filter types */
+lodepng_info_copy(&info, &state->info_png);
+if(state->encoder.auto_convert) {
+LodePNGColorStats stats;
+unsigned allow_convert = 1;
+lodepng_color_stats_init(&stats);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+if(info_png->iccp_defined &&
+isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) {
+/*the PNG specification does not allow to use palette with a GRAY ICC profile, even
+if the palette has only gray colors, so disallow it.*/
+stats.allow_palette = 0;
+}
+if(info_png->iccp_defined &&
+isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) {
+/*the PNG specification does not allow to use grayscale color with RGB ICC profile, so disallow gray.*/
+stats.allow_greyscale = 0;
+}
+#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
+state->error = lodepng_compute_color_stats(&stats, image, w, h, &state->info_raw);
+if(state->error) goto cleanup;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+if(info_png->background_defined) {
+/*the background chunk's color must be taken into account as well*/
+unsigned r = 0, g = 0, b = 0;
+LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16);
+lodepng_convert_rgb(&r, &g, &b,
+info_png->background_r, info_png->background_g, info_png->background_b, &mode16, &info_png->color);
+state->error = lodepng_color_stats_add(&stats, r, g, b, 65535);
+if(state->error) goto cleanup;
+}
+#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
+state->error = auto_choose_color(&auto_color, &state->info_raw, &stats);
+if(state->error) goto cleanup;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+if(info_png->sbit_defined) {
+/*if sbit is defined, due to strict requirements of which sbit values can be present for which color modes,
+auto_convert can't be done in many cases. However, do support a few cases here.
+TODO: more conversions may be possible, and it may also be possible to get a more appropriate color type out of
+auto_choose_color if knowledge about sbit is used beforehand
+*/
+unsigned sbit_max = LODEPNG_MAX(LODEPNG_MAX(LODEPNG_MAX(info_png->sbit_r, info_png->sbit_g),
+info_png->sbit_b), info_png->sbit_a);
+unsigned equal = (!info_png->sbit_g || info_png->sbit_g == info_png->sbit_r)
+&& (!info_png->sbit_b || info_png->sbit_b == info_png->sbit_r)
+&& (!info_png->sbit_a || info_png->sbit_a == info_png->sbit_r);
+allow_convert = 0;
+if(info.color.colortype == LCT_PALETTE &&
+auto_color.colortype == LCT_PALETTE) {
+/* input and output are palette, and in this case it may happen that palette data is
+expected to be copied from info_raw into the info_png */
+allow_convert = 1;
+}
+/*going from 8-bit RGB to palette (or 16-bit as long as sbit_max <= 8) is possible
+since both are 8-bit RGB for sBIT's purposes*/
+if(info.color.colortype == LCT_RGB &&
+auto_color.colortype == LCT_PALETTE && sbit_max <= 8) {
+allow_convert = 1;
+}
+/*going from 8-bit RGBA to palette is also ok but only if sbit_a is exactly 8*/
+if(info.color.colortype == LCT_RGBA && auto_color.colortype == LCT_PALETTE &&
+info_png->sbit_a == 8 && sbit_max <= 8) {
+allow_convert = 1;
+}
+/*going from 16-bit RGB(A) to 8-bit RGB(A) is ok if all sbit values are <= 8*/
+if((info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA) && info.color.bitdepth == 16 &&
+auto_color.colortype == info.color.colortype && auto_color.bitdepth == 8 &&
+sbit_max <= 8) {
+allow_convert = 1;
+}
+/*going to less channels is ok if all bit values are equal (all possible values in sbit,
+as well as the chosen bitdepth of the result). Due to how auto_convert works,
+we already know that auto_color.colortype has less than or equal amount of channels than
+info.colortype. Palette is not used here. This conversion is not allowed if
+info_png->sbit_r < auto_color.bitdepth, because specifically for alpha, non-presence of
+an sbit value heavily implies that alpha's bit depth is equal to the PNG bit depth (rather
+than the bit depths set in the r, g and b sbit values, by how the PNG specification describes
+handling tRNS chunk case with sBIT), so be conservative here about ignoring user input.*/
+if(info.color.colortype != LCT_PALETTE && auto_color.colortype != LCT_PALETTE &&
+equal && info_png->sbit_r == auto_color.bitdepth) {
+allow_convert = 1;
+}
+}
+#endif
+if(state->encoder.force_palette) {
+if(info.color.colortype != LCT_GREY && info.color.colortype != LCT_GREY_ALPHA &&
+(auto_color.colortype == LCT_GREY || auto_color.colortype == LCT_GREY_ALPHA)) {
+/*user speficially forced a PLTE palette, so cannot convert to grayscale types because
+the PNG specification only allows writing a suggested palette in PLTE for truecolor types*/
+allow_convert = 0;
+}
+}
+if(allow_convert) {
+lodepng_color_mode_copy(&info.color, &auto_color);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*also convert the background chunk*/
+if(info_png->background_defined) {
+if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b,
+info_png->background_r, info_png->background_g, info_png->background_b, &info.color, &info_png->color)) {
+state->error = 104;
+goto cleanup;
+}
+}
+#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
+}
+}
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+if(info_png->iccp_defined) {
+unsigned gray_icc = isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size);
+unsigned rgb_icc = isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size);
+unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA;
+if(!gray_icc && !rgb_icc) {
+state->error = 100; /* Disallowed profile color type for PNG */
+goto cleanup;
+}
+if(gray_icc != gray_png) {
+/*Not allowed to use RGB/RGBA/palette with GRAY ICC profile or vice versa,
+or in case of auto_convert, it wasn't possible to find appropriate model*/
+state->error = state->encoder.auto_convert ? 102 : 101;
+goto cleanup;
+}
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) {
+unsigned char* converted;
+size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7u) / 8u;
+converted = (unsigned char*)lodepng_malloc(size);
+if(!converted && size) state->error = 83; /*alloc fail*/
+if(!state->error) {
+state->error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h);
+}
+if(!state->error) {
+state->error = preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder);
+}
+lodepng_free(converted);
+if(state->error) goto cleanup;
+} else {
+state->error = preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder);
+if(state->error) goto cleanup;
+}
+/* output all PNG chunks */ {
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+size_t i;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+/*write signature and chunks*/
+state->error = writeSignature(&outv);
+if(state->error) goto cleanup;
+/*IHDR*/
+state->error = addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method);
+if(state->error) goto cleanup;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*unknown chunks between IHDR and PLTE*/
+if(info.unknown_chunks_data[0]) {
+state->error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]);
+if(state->error) goto cleanup;
+}
+/*color profile chunks must come before PLTE */
+if(info.iccp_defined) {
+state->error = addChunk_iCCP(&outv, &info, &state->encoder.zlibsettings);
+if(state->error) goto cleanup;
+}
+if(info.srgb_defined) {
+state->error = addChunk_sRGB(&outv, &info);
+if(state->error) goto cleanup;
+}
+if(info.gama_defined) {
+state->error = addChunk_gAMA(&outv, &info);
+if(state->error) goto cleanup;
+}
+if(info.chrm_defined) {
+state->error = addChunk_cHRM(&outv, &info);
+if(state->error) goto cleanup;
+}
+if(info_png->sbit_defined) {
+state->error = addChunk_sBIT(&outv, &info);
+if(state->error) goto cleanup;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+/*PLTE*/
+if(info.color.colortype == LCT_PALETTE) {
+state->error = addChunk_PLTE(&outv, &info.color);
+if(state->error) goto cleanup;
+}
+if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) {
+/*force_palette means: write suggested palette for truecolor in PLTE chunk*/
+state->error = addChunk_PLTE(&outv, &info.color);
+if(state->error) goto cleanup;
+}
+/*tRNS (this will only add if when necessary) */
+state->error = addChunk_tRNS(&outv, &info.color);
+if(state->error) goto cleanup;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*bKGD (must come between PLTE and the IDAt chunks*/
+if(info.background_defined) {
+state->error = addChunk_bKGD(&outv, &info);
+if(state->error) goto cleanup;
+}
+/*pHYs (must come before the IDAT chunks)*/
+if(info.phys_defined) {
+state->error = addChunk_pHYs(&outv, &info);
+if(state->error) goto cleanup;
+}
+/*unknown chunks between PLTE and IDAT*/
+if(info.unknown_chunks_data[1]) {
+state->error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]);
+if(state->error) goto cleanup;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+/*IDAT (multiple IDAT chunks must be consecutive)*/
+state->error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings);
+if(state->error) goto cleanup;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*tIME*/
+if(info.time_defined) {
+state->error = addChunk_tIME(&outv, &info.time);
+if(state->error) goto cleanup;
+}
+/*tEXt and/or zTXt*/
+for(i = 0; i != info.text_num; ++i) {
+if(lodepng_strlen(info.text_keys[i]) > 79) {
+state->error = 66; /*text chunk too large*/
+goto cleanup;
+}
+if(lodepng_strlen(info.text_keys[i]) < 1) {
+state->error = 67; /*text chunk too small*/
+goto cleanup;
+}
+if(state->encoder.text_compression) {
+state->error = addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings);
+if(state->error) goto cleanup;
+} else {
+state->error = addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]);
+if(state->error) goto cleanup;
+}
+}
+/*LodePNG version id in text chunk*/
+if(state->encoder.add_id) {
+unsigned already_added_id_text = 0;
+for(i = 0; i != info.text_num; ++i) {
+const char* k = info.text_keys[i];
+/* Could use strcmp, but we're not calling or reimplementing this C library function for this use only */
+if(k[0] == 'L' && k[1] == 'o' && k[2] == 'd' && k[3] == 'e' &&
+k[4] == 'P' && k[5] == 'N' && k[6] == 'G' && k[7] == '\0') {
+already_added_id_text = 1;
+break;
+}
+}
+if(already_added_id_text == 0) {
+state->error = addChunk_tEXt(&outv, "LodePNG", LODEPNG_VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/
+if(state->error) goto cleanup;
+}
+}
+/*iTXt*/
+for(i = 0; i != info.itext_num; ++i) {
+if(lodepng_strlen(info.itext_keys[i]) > 79) {
+state->error = 66; /*text chunk too large*/
+goto cleanup;
+}
+if(lodepng_strlen(info.itext_keys[i]) < 1) {
+state->error = 67; /*text chunk too small*/
+goto cleanup;
+}
+state->error = addChunk_iTXt(
+&outv, state->encoder.text_compression,
+info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i],
+&state->encoder.zlibsettings);
+if(state->error) goto cleanup;
+}
+/*unknown chunks between IDAT and IEND*/
+if(info.unknown_chunks_data[2]) {
+state->error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]);
+if(state->error) goto cleanup;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+state->error = addChunk_IEND(&outv);
+if(state->error) goto cleanup;
+}
+cleanup:
+lodepng_info_cleanup(&info);
+lodepng_free(data);
+lodepng_color_mode_cleanup(&auto_color);
+/*instead of cleaning the vector up, give it to the output*/
+*out = outv.data;
+*outsize = outv.size;
+return state->error;
+}
+unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image,
+unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
+unsigned error;
+LodePNGState state;
+lodepng_state_init(&state);
+state.info_raw.colortype = colortype;
+state.info_raw.bitdepth = bitdepth;
+state.info_png.color.colortype = colortype;
+state.info_png.color.bitdepth = bitdepth;
+lodepng_encode(out, outsize, image, w, h, &state);
+error = state.error;
+lodepng_state_cleanup(&state);
+return error;
+}
+unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) {
+return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8);
+}
+unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) {
+return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8);
+}
+#ifdef LODEPNG_COMPILE_DISK
+unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth) {
+unsigned char* buffer;
+size_t buffersize;
+unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth);
+if(!error) error = lodepng_save_file(buffer, buffersize, filename);
+lodepng_free(buffer);
+return error;
+}
+unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) {
+return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8);
+}
+unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) {
+return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8);
+}
+#endif /*LODEPNG_COMPILE_DISK*/
+void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) {
+lodepng_compress_settings_init(&settings->zlibsettings);
+settings->filter_palette_zero = 1;
+settings->filter_strategy = LFS_MINSUM;
+settings->auto_convert = 1;
+settings->force_palette = 0;
+settings->predefined_filters = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+settings->add_id = 0;
+settings->text_compression = 1;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_PNG*/
+#ifdef LODEPNG_COMPILE_ERROR_TEXT
+/*
+This returns the description of a numerical error code in English. This is also
+the documentation of all the error codes.
+*/
+const char* lodepng_error_text(unsigned code) {
+switch(code) {
+case 0: return "no error, everything went ok";
+case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/
+case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/
+case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/
+case 13: return "problem while processing dynamic deflate block";
+case 14: return "problem while processing dynamic deflate block";
+case 15: return "problem while processing dynamic deflate block";
+/*this error could happen if there are only 0 or 1 symbols present in the huffman code:*/
+case 16: return "invalid code while processing dynamic deflate block";
+case 17: return "end of out buffer memory reached while inflating";
+case 18: return "invalid distance code while inflating";
+case 19: return "end of out buffer memory reached while inflating";
+case 20: return "invalid deflate block BTYPE encountered while decoding";
+case 21: return "NLEN is not ones complement of LEN in a deflate block";
+/*end of out buffer memory reached while inflating:
+This can happen if the inflated deflate data is longer than the amount of bytes required to fill up
+all the pixels of the image, given the color depth and image dimensions. Something that doesn't
+happen in a normal, well encoded, PNG image.*/
+case 22: return "end of out buffer memory reached while inflating";
+case 23: return "end of in buffer memory reached while inflating";
+case 24: return "invalid FCHECK in zlib header";
+case 25: return "invalid compression method in zlib header";
+case 26: return "FDICT encountered in zlib header while it's not used for PNG";
+case 27: return "PNG file is smaller than a PNG header";
+/*Checks the magic file header, the first 8 bytes of the PNG file*/
+case 28: return "incorrect PNG signature, it's no PNG or corrupted";
+case 29: return "first chunk is not the header chunk";
+case 30: return "chunk length too large, chunk broken off at end of file";
+case 31: return "illegal PNG color type or bpp";
+case 32: return "illegal PNG compression method";
+case 33: return "illegal PNG filter method";
+case 34: return "illegal PNG interlace method";
+case 35: return "chunk length of a chunk is too large or the chunk too small";
+case 36: return "illegal PNG filter type encountered";
+case 37: return "illegal bit depth for this color type given";
+case 38: return "the palette is too small or too big"; /*0, or more than 256 colors*/
+case 39: return "tRNS chunk before PLTE or has more entries than palette size";
+case 40: return "tRNS chunk has wrong size for grayscale image";
+case 41: return "tRNS chunk has wrong size for RGB image";
+case 42: return "tRNS chunk appeared while it was not allowed for this color type";
+case 43: return "bKGD chunk has wrong size for palette image";
+case 44: return "bKGD chunk has wrong size for grayscale image";
+case 45: return "bKGD chunk has wrong size for RGB image";
+case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?";
+case 49: return "jumped past memory while generating dynamic huffman tree";
+case 50: return "jumped past memory while generating dynamic huffman tree";
+case 51: return "jumped past memory while inflating huffman block";
+case 52: return "jumped past memory while inflating";
+case 53: return "size of zlib data too small";
+case 54: return "repeat symbol in tree while there was no value symbol yet";
+/*jumped past tree while generating huffman tree, this could be when the
+tree will have more leaves than symbols after generating it out of the
+given lengths. They call this an oversubscribed dynamic bit lengths tree in zlib.*/
+case 55: return "jumped past tree while generating huffman tree";
+case 56: return "given output image colortype or bitdepth not supported for color conversion";
+case 57: return "invalid CRC encountered (checking CRC can be disabled)";
+case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)";
+case 59: return "requested color conversion not supported";
+case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)";
+case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)";
+/*LodePNG leaves the choice of RGB to grayscale conversion formula to the user.*/
+case 62: return "conversion from color to grayscale not supported";
+/*(2^31-1)*/
+case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk";
+/*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/
+case 64: return "the length of the END symbol 256 in the Huffman tree is 0";
+case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes";
+case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte";
+case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors";
+case 69: return "unknown chunk type with 'critical' flag encountered by the decoder";
+case 71: return "invalid interlace mode given to encoder (must be 0 or 1)";
+case 72: return "while decoding, invalid compression method encountering in zTXt or iTXt chunk (it must be 0)";
+case 73: return "invalid tIME chunk size";
+case 74: return "invalid pHYs chunk size";
+/*length could be wrong, or data chopped off*/
+case 75: return "no null termination char found while decoding text chunk";
+case 76: return "iTXt chunk too short to contain required bytes";
+case 77: return "integer overflow in buffer size";
+case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/
+case 79: return "failed to open file for writing";
+case 80: return "tried creating a tree of 0 symbols";
+case 81: return "lazy matching at pos 0 is impossible";
+case 82: return "color conversion to palette requested while a color isn't in palette, or index out of bounds";
+case 83: return "memory allocation failed";
+case 84: return "given image too small to contain all pixels to be encoded";
+case 86: return "impossible offset in lz77 encoding (internal bug)";
+case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined";
+case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy";
+case 89: return "text chunk keyword too short or long: must have size 1-79";
+/*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/
+case 90: return "windowsize must be a power of two";
+case 91: return "invalid decompressed idat size";
+case 92: return "integer overflow due to too many pixels";
+case 93: return "zero width or height is invalid";
+case 94: return "header chunk must have a size of 13 bytes";
+case 95: return "integer overflow with combined idat chunk size";
+case 96: return "invalid gAMA chunk size";
+case 97: return "invalid cHRM chunk size";
+case 98: return "invalid sRGB chunk size";
+case 99: return "invalid sRGB rendering intent";
+case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY";
+case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa";
+case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification";
+case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?";
+case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)";
+case 105: return "integer overflow of bitsize";
+case 106: return "PNG file must have PLTE chunk if color type is palette";
+case 107: return "color convert from palette mode requested without setting the palette data in it";
+case 108: return "tried to add more than 256 values to a palette";
+/*this limit can be configured in LodePNGDecompressSettings*/
+case 109: return "tried to decompress zlib or deflate data larger than desired max_output_size";
+case 110: return "custom zlib or inflate decompression failed";
+case 111: return "custom zlib or deflate compression failed";
+/*max text size limit can be configured in LodePNGDecoderSettings. This error prevents
+unreasonable memory consumption when decoding due to impossibly large text sizes.*/
+case 112: return "compressed text unreasonably large";
+/*max ICC size limit can be configured in LodePNGDecoderSettings. This error prevents
+unreasonable memory consumption when decoding due to impossibly large ICC profile*/
+case 113: return "ICC profile unreasonably large";
+case 114: return "sBIT chunk has wrong size for the color type of the image";
+case 115: return "sBIT value out of range";
+}
+return "unknown error code";
+}
+#endif /*LODEPNG_COMPILE_ERROR_TEXT*/
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // C++ Wrapper                                                          // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+#ifdef LODEPNG_COMPILE_CPP
+namespace lodepng {
+#ifdef LODEPNG_COMPILE_DISK
+unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename) {
+long size = lodepng_filesize(filename.c_str());
+if(size < 0) return 78;
+buffer.resize((size_t)size);
+return size == 0 ? 0 : lodepng_buffer_file(&buffer[0], (size_t)size, filename.c_str());
+}
+/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
+unsigned save_file(const std::vector<unsigned char>& buffer, const std::string& filename) {
+return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str());
+}
+#endif /* LODEPNG_COMPILE_DISK */
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_DECODER
+unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+const LodePNGDecompressSettings& settings) {
+unsigned char* buffer = 0;
+size_t buffersize = 0;
+unsigned error = zlib_decompress(&buffer, &buffersize, 0, in, insize, &settings);
+if(buffer) {
+out.insert(out.end(), buffer, &buffer[buffersize]);
+lodepng_free(buffer);
+}
+return error;
+}
+unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+const LodePNGDecompressSettings& settings) {
+return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings);
+}
+#endif /* LODEPNG_COMPILE_DECODER */
+#ifdef LODEPNG_COMPILE_ENCODER
+unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+const LodePNGCompressSettings& settings) {
+unsigned char* buffer = 0;
+size_t buffersize = 0;
+unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings);
+if(buffer) {
+out.insert(out.end(), buffer, &buffer[buffersize]);
+lodepng_free(buffer);
+}
+return error;
+}
+unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+const LodePNGCompressSettings& settings) {
+return compress(out, in.empty() ? 0 : &in[0], in.size(), settings);
+}
+#endif /* LODEPNG_COMPILE_ENCODER */
+#endif /* LODEPNG_COMPILE_ZLIB */
+#ifdef LODEPNG_COMPILE_PNG
+State::State() {
+lodepng_state_init(this);
+}
+State::State(const State& other) {
+lodepng_state_init(this);
+lodepng_state_copy(this, &other);
+}
+State::~State() {
+lodepng_state_cleanup(this);
+}
+State& State::operator=(const State& other) {
+lodepng_state_copy(this, &other);
+return *this;
+}
+#ifdef LODEPNG_COMPILE_DECODER
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const unsigned char* in,
+size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
+unsigned char* buffer = 0;
+unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth);
+if(buffer && !error) {
+State state;
+state.info_raw.colortype = colortype;
+state.info_raw.bitdepth = bitdepth;
+size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
+out.insert(out.end(), buffer, &buffer[buffersize]);
+}
+lodepng_free(buffer);
+return error;
+}
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+const std::vector<unsigned char>& in, LodePNGColorType colortype, unsigned bitdepth) {
+return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth);
+}
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+State& state,
+const unsigned char* in, size_t insize) {
+unsigned char* buffer = NULL;
+unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize);
+if(buffer && !error) {
+size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
+out.insert(out.end(), buffer, &buffer[buffersize]);
+}
+lodepng_free(buffer);
+return error;
+}
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+State& state,
+const std::vector<unsigned char>& in) {
+return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size());
+}
+#ifdef LODEPNG_COMPILE_DISK
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename,
+LodePNGColorType colortype, unsigned bitdepth) {
+std::vector<unsigned char> buffer;
+/* safe output values in case error happens */
+w = h = 0;
+unsigned error = load_file(buffer, filename);
+if(error) return error;
+return decode(out, w, h, buffer, colortype, bitdepth);
+}
+#endif /* LODEPNG_COMPILE_DECODER */
+#endif /* LODEPNG_COMPILE_DISK */
+#ifdef LODEPNG_COMPILE_ENCODER
+unsigned encode(std::vector<unsigned char>& out, const unsigned char* in, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth) {
+unsigned char* buffer;
+size_t buffersize;
+unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth);
+if(buffer) {
+out.insert(out.end(), buffer, &buffer[buffersize]);
+lodepng_free(buffer);
+}
+return error;
+}
+unsigned encode(std::vector<unsigned char>& out,
+const std::vector<unsigned char>& in, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth) {
+if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
+return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
+}
+unsigned encode(std::vector<unsigned char>& out,
+const unsigned char* in, unsigned w, unsigned h,
+State& state) {
+unsigned char* buffer;
+size_t buffersize;
+unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state);
+if(buffer) {
+out.insert(out.end(), buffer, &buffer[buffersize]);
+lodepng_free(buffer);
+}
+return error;
+}
+unsigned encode(std::vector<unsigned char>& out,
+const std::vector<unsigned char>& in, unsigned w, unsigned h,
+State& state) {
+if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84;
+return encode(out, in.empty() ? 0 : &in[0], w, h, state);
+}
+#ifdef LODEPNG_COMPILE_DISK
+unsigned encode(const std::string& filename,
+const unsigned char* in, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth) {
+std::vector<unsigned char> buffer;
+unsigned error = encode(buffer, in, w, h, colortype, bitdepth);
+if(!error) error = save_file(buffer, filename);
+return error;
+}
+unsigned encode(const std::string& filename,
+const std::vector<unsigned char>& in, unsigned w, unsigned h,
+LodePNGColorType colortype, unsigned bitdepth) {
+if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
+return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
+}
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_ENCODER */
+#endif /* LODEPNG_COMPILE_PNG */
+} /* namespace lodepng */
+#endif /*LODEPNG_COMPILE_CPP*/

Mercurial > games > semicongine

comparison semiconginev2/old/resources/lodepng.c @ 1218:56781cc0fc7c compiletime-tests