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Diffstat (limited to 'lib/lodepng.c')
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diff --git a/lib/lodepng.c b/lib/lodepng.c new file mode 100644 index 0000000000..ba21cd235f --- /dev/null +++ b/lib/lodepng.c @@ -0,0 +1,5928 @@ +/* +LodePNG version 20120729 + +Copyright (c) 2005-2012 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" + +#include <stdio.h> +#include <stdlib.h> + +#ifdef __BAREBOX__ +#include <common.h> +#include <malloc.h> +#include <fs.h> +#include <fcntl.h> +#endif + +#ifdef LODEPNG_COMPILE_CPP +#include <fstream> +#endif /*LODEPNG_COMPILE_CPP*/ + +#define VERSION_STRING "20120729" + +/* +This source file is built up in 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 +*/ + +/*The malloc, realloc and free functions defined here with "my" in front of the +name, so that you can easily change them to others related to your platform in +this one location if needed. Everything else in the code calls these.*/ + +static void* mymalloc(size_t size) +{ + return malloc(size); +} + +static void* myrealloc(void* ptr, size_t new_size) +{ + return realloc(ptr, new_size); +} + +static void myfree(void* ptr) +{ + free(ptr); +} + +/* +Declaration of the custom functions used if LODEPNG_COMPILE_ZLIB isn't defined +or LODEPNG_CUSTOM_ZLIB_DECODER or LODEPNG_CUSTOM_ZLIB_ENCODER are enabled. + +In that case, you need to define these yourself (which you can do in one of your +own source files) so that LodePNG can link to it. + +By default, this is not needed. If LODEPNG_COMPILE_ZLIB isn't defined, then only +the two zlib related ones are needed. + +If needed, the functions must act as follows: +*out must be NULL and *outsize must be 0 initially, and after the function is done, +*out must point to the decompressed data, *outsize must be the size of it, and must +be the size of the useful data in bytes, not the alloc size. +*/ +unsigned lodepng_custom_zlib_decompress(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings); +unsigned lodepng_custom_zlib_compress(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGCompressSettings* settings); +unsigned lodepng_custom_inflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings); +unsigned lodepng_custom_deflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGCompressSettings* settings); + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // Tools for C, and common code for PNG and Zlib. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/* +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_resizev(&frequencies_ll, 286, 0)) 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;\ +} + +/* +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 +/*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; + myfree(((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) +{ + if(size * sizeof(unsigned) > p->allocsize) + { + size_t newsize = size * sizeof(unsigned) * 2; + void* data = myrealloc(p->data, newsize); + if(data) + { + p->allocsize = newsize; + p->data = (unsigned*)data; + p->size = size; + } + else return 0; + } + else p->size = size; + return 1; +} + +/*resize and give all new elements the value*/ +static unsigned uivector_resizev(uivector* p, size_t size, unsigned value) +{ + size_t oldsize = p->size, i; + if(!uivector_resize(p, size)) return 0; + for(i = oldsize; i < size; i++) p->data[i] = value; + return 1; +} + +static void uivector_init(uivector* p) +{ + p->data = NULL; + p->size = p->allocsize = 0; +} + +#ifdef LODEPNG_COMPILE_ENCODER +/*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; +} + +/*copy q to p, returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned uivector_copy(uivector* p, const uivector* q) +{ + size_t i; + if(!uivector_resize(p, q->size)) return 0; + for(i = 0; i < q->size; i++) p->data[i] = q->data[i]; + return 1; +} + +static void uivector_swap(uivector* p, uivector* q) +{ + size_t tmp; + unsigned* tmpp; + tmp = p->size; p->size = q->size; q->size = tmp; + tmp = p->allocsize; p->allocsize = q->allocsize; q->allocsize = tmp; + tmpp = p->data; p->data = q->data; q->data = tmpp; +} +#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; + +static void ucvector_cleanup(void* p) +{ + ((ucvector*)p)->size = ((ucvector*)p)->allocsize = 0; + myfree(((ucvector*)p)->data); + ((ucvector*)p)->data = NULL; +} + +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned ucvector_resize(ucvector* p, size_t size) +{ + if(size * sizeof(unsigned char) > p->allocsize) + { + size_t newsize = size * sizeof(unsigned char) * 2; + void* data = myrealloc(p->data, newsize); + if(data) + { + p->allocsize = newsize; + p->data = (unsigned char*)data; + p->size = size; + } + else return 0; /*error: not enough memory*/ + } + else p->size = size; + return 1; +} + +#ifdef LODEPNG_COMPILE_DECODER +#ifdef LODEPNG_COMPILE_PNG +/*resize and give all new elements the value*/ +static unsigned ucvector_resizev(ucvector* p, size_t size, unsigned char value) +{ + size_t oldsize = p->size, i; + if(!ucvector_resize(p, size)) return 0; + for(i = oldsize; i < size; i++) p->data[i] = value; + return 1; +} +#endif /*LODEPNG_COMPILE_PNG*/ +#endif /*LODEPNG_COMPILE_DECODER*/ + +static void ucvector_init(ucvector* p) +{ + p->data = NULL; + p->size = p->allocsize = 0; +} + +#ifdef LODEPNG_COMPILE_ZLIB +/*you can both convert from vector to buffer&size and vica versa. If you use +init_buffer to take over a buffer and size, it is not needed to use cleanup*/ +static void ucvector_init_buffer(ucvector* p, unsigned char* buffer, size_t size) +{ + p->data = buffer; + p->allocsize = p->size = size; +} +#endif /*LODEPNG_COMPILE_ZLIB*/ + +#ifdef LODEPNG_COMPILE_ENCODER +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned ucvector_push_back(ucvector* p, unsigned char c) +{ + if(!ucvector_resize(p, p->size + 1)) return 0; + p->data[p->size - 1] = c; + return 1; +} +#endif /*LODEPNG_COMPILE_ENCODER*/ + + +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_PNG +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned string_resize(char** out, size_t size) +{ + char* data = (char*)myrealloc(*out, size + 1); + if(data) + { + data[size] = 0; /*null termination char*/ + *out = data; + } + return data != 0; +} + +/*init a {char*, size_t} pair for use as string*/ +static void string_init(char** out) +{ + *out = NULL; + string_resize(out, 0); +} + +/*free the above pair again*/ +static void string_cleanup(char** out) +{ + myfree(*out); + *out = NULL; +} + +static void string_set(char** out, const char* in) +{ + size_t insize = strlen(in), i = 0; + if(string_resize(out, insize)) + { + for(i = 0; i < insize; i++) + { + (*out)[i] = in[i]; + } + } +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +#endif /*LODEPNG_COMPILE_PNG*/ + +/* ////////////////////////////////////////////////////////////////////////// */ + +unsigned lodepng_read32bitInt(const unsigned char* buffer) +{ + return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]; +} + +/*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); +} + +#ifdef LODEPNG_COMPILE_ENCODER +static void lodepng_add32bitInt(ucvector* buffer, unsigned value) +{ + ucvector_resize(buffer, buffer->size + 4); /*todo: give error if resize failed*/ + lodepng_set32bitInt(&buffer->data[buffer->size - 4], value); +} +#endif /*LODEPNG_COMPILE_ENCODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / File IO / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_DISK + +unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) +{ + FILE* file; + long size; + + /*provide some proper output values if error will happen*/ + *out = 0; + *outsize = 0; + + file = fopen(filename, "rb"); + if(!file) return 78; + + /*get filesize:*/ + fseek(file , 0 , SEEK_END); + size = ftell(file); + rewind(file); + + /*read contents of the file into the vector*/ + *outsize = 0; + *out = (unsigned char*)mymalloc((size_t)size); + if(size && (*out)) (*outsize) = fread(*out, 1, (size_t)size, file); + + fclose(file); + if(!(*out) && size) return 83; /*the above malloc failed*/ + return 0; +} + +/*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((char*)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 +/*TODO: this ignores potential out of memory errors*/ +static void addBitToStream(size_t* bitpointer, ucvector* bitstream, unsigned char bit) +{ + /*add a new byte at the end*/ + if((*bitpointer) % 8 == 0) ucvector_push_back(bitstream, (unsigned char)0); + /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/ + (bitstream->data[bitstream->size - 1]) |= (bit << ((*bitpointer) & 0x7)); + (*bitpointer)++; +} + +static void addBitsToStream(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits) +{ + size_t i; + for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> i) & 1)); +} + +static void addBitsToStreamReversed(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits) +{ + size_t i; + for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> (nbits - 1 - i)) & 1)); +} +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#ifdef LODEPNG_COMPILE_DECODER + +#define READBIT(bitpointer, bitstream) ((bitstream[bitpointer >> 3] >> (bitpointer & 0x7)) & (unsigned char)1) + +static unsigned char readBitFromStream(size_t* bitpointer, const unsigned char* bitstream) +{ + unsigned char result = (unsigned char)(READBIT(*bitpointer, bitstream)); + (*bitpointer)++; + return result; +} + +static unsigned readBitsFromStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) +{ + unsigned result = 0, i; + for(i = 0; i < nbits; i++) + { + result += ((unsigned)READBIT(*bitpointer, bitstream)) << i; + (*bitpointer)++; + } + return result; +} +#endif /*LODEPNG_COMPILE_DECODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / 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, 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* tree2d; + unsigned* tree1d; + unsigned* lengths; /*the lengths of the codes of the 1d-tree*/ + unsigned maxbitlen; /*maximum number of bits a single code can get*/ + unsigned numcodes; /*number of symbols in the alphabet = number of codes*/ +} HuffmanTree; + +/*function used for debug purposes to draw the tree in ascii art with C++*/ +/*#include <iostream> +static void HuffmanTree_draw(HuffmanTree* tree) +{ + std::cout << "tree. length: " << tree->numcodes << " maxbitlen: " << tree->maxbitlen << std::endl; + for(size_t i = 0; i < tree->tree1d.size; i++) + { + if(tree->lengths.data[i]) + std::cout << i << " " << tree->tree1d.data[i] << " " << tree->lengths.data[i] << std::endl; + } + std::cout << std::endl; +}*/ + +static void HuffmanTree_init(HuffmanTree* tree) +{ + tree->tree2d = 0; + tree->tree1d = 0; + tree->lengths = 0; +} + +static void HuffmanTree_cleanup(HuffmanTree* tree) +{ + myfree(tree->tree2d); + myfree(tree->tree1d); + myfree(tree->lengths); +} + +/*the tree representation used by the decoder. return value is error*/ +static unsigned HuffmanTree_make2DTree(HuffmanTree* tree) +{ + unsigned nodefilled = 0; /*up to which node it is filled*/ + unsigned treepos = 0; /*position in the tree (1 of the numcodes columns)*/ + unsigned n, i; + + tree->tree2d = (unsigned*)mymalloc(tree->numcodes * 2 * sizeof(unsigned)); + if(!tree->tree2d) return 83; /*alloc fail*/ + + /* + convert tree1d[] to tree2d[][]. In the 2D array, a value of 32767 means + uninited, a value >= numcodes is an address to another bit, a value < numcodes + is a code. The 2 rows are the 2 possible bit values (0 or 1), there are as + many columns as codes - 1. + A good huffmann tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. + Here, the internal nodes are stored (what their 0 and 1 option point to). + There is only memory for such good tree currently, if there are more nodes + (due to too long length codes), error 55 will happen + */ + for(n = 0; n < tree->numcodes * 2; n++) + { + tree->tree2d[n] = 32767; /*32767 here means the tree2d isn't filled there yet*/ + } + + for(n = 0; n < tree->numcodes; n++) /*the codes*/ + { + for(i = 0; i < tree->lengths[n]; i++) /*the bits for this code*/ + { + unsigned char bit = (unsigned char)((tree->tree1d[n] >> (tree->lengths[n] - i - 1)) & 1); + if(treepos > tree->numcodes - 2) return 55; /*oversubscribed, see comment in lodepng_error_text*/ + if(tree->tree2d[2 * treepos + bit] == 32767) /*not yet filled in*/ + { + if(i + 1 == tree->lengths[n]) /*last bit*/ + { + tree->tree2d[2 * treepos + bit] = n; /*put the current code in it*/ + treepos = 0; + } + else + { + /*put address of the next step in here, first that address has to be found of course + (it's just nodefilled + 1)...*/ + nodefilled++; + /*addresses encoded with numcodes added to it*/ + tree->tree2d[2 * treepos + bit] = nodefilled + tree->numcodes; + treepos = nodefilled; + } + } + else treepos = tree->tree2d[2 * treepos + bit] - tree->numcodes; + } + } + + for(n = 0; n < tree->numcodes * 2; n++) + { + if(tree->tree2d[n] == 32767) tree->tree2d[n] = 0; /*remove possible remaining 32767's*/ + } + + 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) +{ + uivector blcount; + uivector nextcode; + unsigned bits, n, error = 0; + + uivector_init(&blcount); + uivector_init(&nextcode); + + tree->tree1d = (unsigned*)mymalloc(tree->numcodes * sizeof(unsigned)); + if(!tree->tree1d) error = 83; /*alloc fail*/ + + if(!uivector_resizev(&blcount, tree->maxbitlen + 1, 0) + || !uivector_resizev(&nextcode, tree->maxbitlen + 1, 0)) + error = 83; /*alloc fail*/ + + if(!error) + { + /*step 1: count number of instances of each code length*/ + for(bits = 0; bits < tree->numcodes; bits++) blcount.data[tree->lengths[bits]]++; + /*step 2: generate the nextcode values*/ + for(bits = 1; bits <= tree->maxbitlen; bits++) + { + nextcode.data[bits] = (nextcode.data[bits - 1] + blcount.data[bits - 1]) << 1; + } + /*step 3: generate all the codes*/ + for(n = 0; n < tree->numcodes; n++) + { + if(tree->lengths[n] != 0) tree->tree1d[n] = nextcode.data[tree->lengths[n]]++; + } + } + + uivector_cleanup(&blcount); + uivector_cleanup(&nextcode); + + if(!error) return HuffmanTree_make2DTree(tree); + else 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*)mymalloc(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 + +/* +A coin, this is the terminology used for the package-merge algorithm and the +coin collector's problem. This is used to generate the huffman tree. +A coin can be multiple coins (when they're merged) +*/ +typedef struct Coin +{ + uivector symbols; + float weight; /*the sum of all weights in this coin*/ +} Coin; + +static void coin_init(Coin* c) +{ + uivector_init(&c->symbols); +} + +/*argument c is void* so that this dtor can be given as function pointer to the vector resize function*/ +static void coin_cleanup(void* c) +{ + uivector_cleanup(&((Coin*)c)->symbols); +} + +static void coin_copy(Coin* c1, const Coin* c2) +{ + c1->weight = c2->weight; + uivector_copy(&c1->symbols, &c2->symbols); +} + +static void add_coins(Coin* c1, const Coin* c2) +{ + size_t i; + for(i = 0; i < c2->symbols.size; i++) uivector_push_back(&c1->symbols, c2->symbols.data[i]); + c1->weight += c2->weight; +} + +static void init_coins(Coin* coins, size_t num) +{ + size_t i; + for(i = 0; i < num; i++) coin_init(&coins[i]); +} + +static void cleanup_coins(Coin* coins, size_t num) +{ + size_t i; + for(i = 0; i < num; i++) coin_cleanup(&coins[i]); +} + +/* +This uses a simple combsort to sort the data. This function is not critical for +overall encoding speed and the data amount isn't that large. +*/ +static void sort_coins(Coin* data, size_t amount) +{ + size_t gap = amount; + unsigned char swapped = 0; + while((gap > 1) || swapped) + { + size_t i; + gap = (gap * 10) / 13; /*shrink factor 1.3*/ + if(gap == 9 || gap == 10) gap = 11; /*combsort11*/ + if(gap < 1) gap = 1; + swapped = 0; + for(i = 0; i < amount - gap; i++) + { + size_t j = i + gap; + if(data[j].weight < data[i].weight) + { + float temp = data[j].weight; data[j].weight = data[i].weight; data[i].weight = temp; + uivector_swap(&data[i].symbols, &data[j].symbols); + swapped = 1; + } + } + } +} + +static unsigned append_symbol_coins(Coin* coins, const unsigned* frequencies, unsigned numcodes, size_t sum) +{ + unsigned i; + unsigned j = 0; /*index of present symbols*/ + for(i = 0; i < numcodes; i++) + { + if(frequencies[i] != 0) /*only include symbols that are present*/ + { + coins[j].weight = frequencies[i] / (float)sum; + uivector_push_back(&coins[j].symbols, i); + j++; + } + } + return 0; +} + +unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, + size_t numcodes, unsigned maxbitlen) +{ + unsigned i, j; + size_t sum = 0, numpresent = 0; + unsigned error = 0; + Coin* coins; /*the coins of the currently calculated row*/ + Coin* prev_row; /*the previous row of coins*/ + unsigned numcoins; + unsigned coinmem; + + if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/ + + for(i = 0; i < numcodes; i++) + { + if(frequencies[i] > 0) + { + numpresent++; + sum += frequencies[i]; + } + } + + for(i = 0; i < numcodes; i++) lengths[i] = 0; + + /*there are no symbols at all, in that case add one symbol of value 0 to the tree (see RFC 1951 section 3.2.7) */ + if(numpresent == 0) + { + lengths[0] = 1; + } + /*the package merge algorithm gives wrong results if there's only one symbol + (theoretically 0 bits would then suffice, but we need a proper symbol for zlib)*/ + else if(numpresent == 1) + { + for(i = 0; i < numcodes; i++) if(frequencies[i]) lengths[i] = 1; + } + else + { + /*Package-Merge algorithm represented by coin collector's problem + For every symbol, maxbitlen coins will be created*/ + + coinmem = numpresent * 2; /*max amount of coins needed with the current algo*/ + coins = (Coin*)mymalloc(sizeof(Coin) * coinmem); + prev_row = (Coin*)mymalloc(sizeof(Coin) * coinmem); + if(!coins || !prev_row) return 83; /*alloc fail*/ + init_coins(coins, coinmem); + init_coins(prev_row, coinmem); + + /*first row, lowest denominator*/ + error = append_symbol_coins(coins, frequencies, numcodes, sum); + numcoins = numpresent; + sort_coins(coins, numcoins); + if(!error) + { + unsigned numprev = 0; + for(j = 1; j <= maxbitlen && !error; j++) /*each of the remaining rows*/ + { + unsigned tempnum; + Coin* tempcoins; + /*swap prev_row and coins, and their amounts*/ + tempcoins = prev_row; prev_row = coins; coins = tempcoins; + tempnum = numprev; numprev = numcoins; numcoins = tempnum; + + cleanup_coins(coins, numcoins); + init_coins(coins, numcoins); + + numcoins = 0; + + /*fill in the merged coins of the previous row*/ + for(i = 0; i + 1 < numprev; i += 2) + { + /*merge prev_row[i] and prev_row[i + 1] into new coin*/ + Coin* coin = &coins[numcoins++]; + coin_copy(coin, &prev_row[i]); + add_coins(coin, &prev_row[i + 1]); + } + /*fill in all the original symbols again*/ + if(j < maxbitlen) + { + error = append_symbol_coins(coins + numcoins, frequencies, numcodes, sum); + numcoins += numpresent; + } + sort_coins(coins, numcoins); + } + } + + if(!error) + { + /*calculate the lenghts of each symbol, as the amount of times a coin of each symbol is used*/ + for(i = 0; i < numpresent - 1; i++) + { + Coin* coin = &coins[i]; + for(j = 0; j < coin->symbols.size; j++) lengths[coin->symbols.data[j]]++; + } + } + + cleanup_coins(coins, coinmem); + myfree(coins); + cleanup_coins(prev_row, coinmem); + myfree(prev_row); + } + + return error; +} + +/*Create the Huffman tree given the symbol frequencies*/ +static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, + size_t numcodes, unsigned maxbitlen) +{ + unsigned error = 0; + tree->maxbitlen = maxbitlen; + tree->numcodes = (unsigned)numcodes; /*number of symbols*/ + tree->lengths = (unsigned*)myrealloc(tree->lengths, numcodes * sizeof(unsigned)); + if(!tree->lengths) return 83; /*alloc fail*/ + /*initialize all lengths to 0*/ + memset(tree->lengths, 0, numcodes * sizeof(unsigned)); + + error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen); + if(!error) error = HuffmanTree_makeFromLengths2(tree); + return error; +} + +static unsigned HuffmanTree_getCode(const HuffmanTree* tree, unsigned index) +{ + return tree->tree1d[index]; +} + +static unsigned HuffmanTree_getLength(const HuffmanTree* tree, unsigned index) +{ + return tree->lengths[index]; +} +#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*)mymalloc(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); + + myfree(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*)mymalloc(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); + + myfree(bitlen); + return error; +} + +#ifdef LODEPNG_COMPILE_DECODER + +/* +returns the code, or (unsigned)(-1) if error happened +inbitlength is the length of the complete buffer, in bits (so its byte length times 8) +*/ +static unsigned huffmanDecodeSymbol(const unsigned char* in, size_t* bp, + const HuffmanTree* codetree, size_t inbitlength) +{ + unsigned treepos = 0, ct; + for(;;) + { + if(*bp >= inbitlength) return (unsigned)(-1); /*error: end of input memory reached without endcode*/ + /* + decode the symbol from the tree. The "readBitFromStream" code is inlined in + the expression below because this is the biggest bottleneck while decoding + */ + ct = codetree->tree2d[(treepos << 1) + READBIT(*bp, in)]; + (*bp)++; + if(ct < codetree->numcodes) return ct; /*the symbol is decoded, return it*/ + else treepos = ct - codetree->numcodes; /*symbol not yet decoded, instead move tree position*/ + + if(treepos >= codetree->numcodes) return (unsigned)(-1); /*error: it appeared outside the codetree*/ + } +} +#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*/ +static void getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) +{ + /*TODO: check for out of memory errors*/ + generateFixedLitLenTree(tree_ll); + 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, + const unsigned char* in, size_t* bp, size_t inlength) +{ + /*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; + size_t inbitlength = inlength * 8; + + /*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((*bp) >> 3 >= inlength - 2) return 49; /*error: the bit pointer is or will go past the memory*/ + + /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/ + HLIT = readBitsFromStream(bp, in, 5) + 257; + /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/ + HDIST = readBitsFromStream(bp, in, 5) + 1; + /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/ + HCLEN = readBitsFromStream(bp, in, 4) + 4; + + HuffmanTree_init(&tree_cl); + + while(!error) + { + /*read the code length codes out of 3 * (amount of code length codes) bits*/ + + bitlen_cl = (unsigned*)mymalloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned)); + if(!bitlen_cl) ERROR_BREAK(83 /*alloc fail*/); + + for(i = 0; i < NUM_CODE_LENGTH_CODES; i++) + { + if(i < HCLEN) bitlen_cl[CLCL_ORDER[i]] = readBitsFromStream(bp, in, 3); + else bitlen_cl[CLCL_ORDER[i]] = 0; /*if not, it must stay 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*)mymalloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); + bitlen_d = (unsigned*)mymalloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); + if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); + for(i = 0; i < NUM_DEFLATE_CODE_SYMBOLS; i++) bitlen_ll[i] = 0; + for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen_d[i] = 0; + + /*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 = huffmanDecodeSymbol(in, bp, &tree_cl, inbitlength); + 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(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ + if (i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ + + replength += readBitsFromStream(bp, in, 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*/ + if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ + + replength += readBitsFromStream(bp, in, 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*/ + if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ + + replength += readBitsFromStream(bp, in, 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 == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ + { + if(code == (unsigned)(-1)) + { + /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol + (10=no endcode, 11=wrong jump outside of tree)*/ + error = (*bp) > inbitlength ? 10 : 11; + } + else error = 16; /*unexisting code, this can never happen*/ + break; + } + } + 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*/ + } + + myfree(bitlen_cl); + myfree(bitlen_ll); + myfree(bitlen_d); + HuffmanTree_cleanup(&tree_cl); + + return error; +} + +/*inflate a block with dynamic of fixed Huffman tree*/ +static unsigned inflateHuffmanBlock(ucvector* out, const unsigned char* in, size_t* bp, + size_t* pos, size_t inlength, unsigned btype) +{ + unsigned error = 0; + HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/ + HuffmanTree tree_d; /*the huffman tree for distance codes*/ + size_t inbitlength = inlength * 8; + + HuffmanTree_init(&tree_ll); + HuffmanTree_init(&tree_d); + + if(btype == 1) getTreeInflateFixed(&tree_ll, &tree_d); + else if(btype == 2) + { + error = getTreeInflateDynamic(&tree_ll, &tree_d, in, bp, inlength); + } + + while(!error) /*decode all symbols until end reached, breaks at end code*/ + { + /*code_ll is literal, length or end code*/ + unsigned code_ll = huffmanDecodeSymbol(in, bp, &tree_ll, inbitlength); + if(code_ll <= 255) /*literal symbol*/ + { + if((*pos) >= out->size) + { + /*reserve more room at once*/ + if(!ucvector_resize(out, ((*pos) + 1) * 2)) ERROR_BREAK(83 /*alloc fail*/); + } + out->data[(*pos)] = (unsigned char)(code_ll); + (*pos)++; + } + 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, forward, 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(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/ + length += readBitsFromStream(bp, in, numextrabits_l); + + /*part 3: get distance code*/ + code_d = huffmanDecodeSymbol(in, bp, &tree_d, inbitlength); + if(code_d > 29) + { + if(code_ll == (unsigned)(-1)) /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ + { + /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol + (10=no endcode, 11=wrong jump outside of tree)*/ + error = (*bp) > inlength * 8 ? 10 : 11; + } + else error = 18; /*error: invalid distance code (30-31 are never used)*/ + break; + } + distance = DISTANCEBASE[code_d]; + + /*part 4: get extra bits from distance*/ + numextrabits_d = DISTANCEEXTRA[code_d]; + if(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/ + + distance += readBitsFromStream(bp, in, numextrabits_d); + + /*part 5: fill in all the out[n] values based on the length and dist*/ + start = (*pos); + if(distance > start) ERROR_BREAK(52); /*too long backward distance*/ + backward = start - distance; + if((*pos) + length >= out->size) + { + /*reserve more room at once*/ + if(!ucvector_resize(out, ((*pos) + length) * 2)) ERROR_BREAK(83 /*alloc fail*/); + } + + for(forward = 0; forward < length; forward++) + { + out->data[(*pos)] = out->data[backward]; + (*pos)++; + backward++; + if(backward >= start) backward = start - distance; + } + } + else if(code_ll == 256) + { + break; /*end code, break the loop*/ + } + else /*if(code == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ + { + /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol + (10=no endcode, 11=wrong jump outside of tree)*/ + error = (*bp) > inlength * 8 ? 10 : 11; + break; + } + } + + HuffmanTree_cleanup(&tree_ll); + HuffmanTree_cleanup(&tree_d); + + return error; +} + +static unsigned inflateNoCompression(ucvector* out, const unsigned char* in, size_t* bp, size_t* pos, size_t inlength) +{ + /*go to first boundary of byte*/ + size_t p; + unsigned LEN, NLEN, n, error = 0; + while(((*bp) & 0x7) != 0) (*bp)++; + p = (*bp) / 8; /*byte position*/ + + /*read LEN (2 bytes) and NLEN (2 bytes)*/ + if(p >= inlength - 4) return 52; /*error, bit pointer will jump past memory*/ + LEN = in[p] + 256 * in[p + 1]; p += 2; + NLEN = in[p] + 256 * in[p + 1]; p += 2; + + /*check if 16-bit NLEN is really the one's complement of LEN*/ + if(LEN + NLEN != 65535) return 21; /*error: NLEN is not one's complement of LEN*/ + + if((*pos) + LEN >= out->size) + { + if(!ucvector_resize(out, (*pos) + LEN)) return 83; /*alloc fail*/ + } + + /*read the literal data: LEN bytes are now stored in the out buffer*/ + if(p + LEN > inlength) return 23; /*error: reading outside of in buffer*/ + for(n = 0; n < LEN; n++) out->data[(*pos)++] = in[p++]; + + (*bp) = p * 8; + + return error; +} + +static unsigned lodepng_inflatev(ucvector* out, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings) +{ + /*bit pointer in the "in" data, current byte is bp >> 3, current bit is bp & 0x7 (from lsb to msb of the byte)*/ + size_t bp = 0; + unsigned BFINAL = 0; + size_t pos = 0; /*byte position in the out buffer*/ + + unsigned error = 0; + + (void)settings; + + while(!BFINAL) + { + unsigned BTYPE; + if(bp + 2 >= insize * 8) return 52; /*error, bit pointer will jump past memory*/ + BFINAL = readBitFromStream(&bp, in); + BTYPE = 1 * readBitFromStream(&bp, in); + BTYPE += 2 * readBitFromStream(&bp, in); + + if(BTYPE == 3) return 20; /*error: invalid BTYPE*/ + else if(BTYPE == 0) error = inflateNoCompression(out, in, &bp, &pos, insize); /*no compression*/ + else error = inflateHuffmanBlock(out, in, &bp, &pos, insize, BTYPE); /*compression, BTYPE 01 or 10*/ + + if(error) return error; + } + + /*Only now we know the true size of out, resize it to that*/ + if(!ucvector_resize(out, pos)) error = 83; /*alloc fail*/ + + return error; +} + +unsigned lodepng_inflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings) +{ +#if LODEPNG_CUSTOM_ZLIB_DECODER == 2 + if(settings->custom_decoder) + { + return lodepng_custom_inflate(out, outsize, in, insize, settings); + } + else + { +#endif /*LODEPNG_CUSTOM_ZLIB_DECODER == 2*/ + unsigned error; + ucvector v; + ucvector_init_buffer(&v, *out, *outsize); + error = lodepng_inflatev(&v, in, insize, settings); + *out = v.data; + *outsize = v.size; + return error; +#if LODEPNG_CUSTOM_ZLIB_DECODER == 2 + } +#endif /*LODEPNG_CUSTOM_ZLIB_DECODER == 2*/ +} + +#endif /*LODEPNG_COMPILE_DECODER*/ + +#ifdef LODEPNG_COMPILE_ENCODER + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Deflator (Compressor) / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258; + +/*bitlen is the size in bits of the code*/ +static void addHuffmanSymbol(size_t* bp, ucvector* compressed, unsigned code, unsigned bitlen) +{ + addBitsToStreamReversed(bp, compressed, code, bitlen); +} + +/*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) +{ + /*linear search implementation*/ + /*for(size_t i = 1; i < array_size; i++) if(array[i] > value) return i - 1; + return array_size - 1;*/ + + /*binary search implementation (not that much faster) (precondition: array_size > 0)*/ + size_t left = 1; + size_t right = array_size - 1; + while(left <= right) + { + size_t mid = (left + right) / 2; + if(array[mid] <= value) left = mid + 1; /*the value to find is more to the right*/ + else if(array[mid - 1] > value) right = mid - 1; /*the value to find is more to the left*/ + else return mid - 1; + } + return array_size - 1; +} + +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]); + + uivector_push_back(values, length_code + FIRST_LENGTH_CODE_INDEX); + uivector_push_back(values, extra_length); + uivector_push_back(values, dist_code); + uivector_push_back(values, extra_distance); +} + +static const unsigned HASH_NUM_VALUES = 65536; +static const unsigned HASH_NUM_CHARACTERS = 3; +static const unsigned HASH_SHIFT = 2; +/* +The HASH_NUM_CHARACTERS value is used to make encoding faster by using longer +sequences to generate a hash value from the stream bytes. Setting it to 3 +gives exactly the same compression as the brute force method, since deflate's +run length encoding starts with lengths of 3. Setting it to higher values, +like 6, can make the encoding faster (not always though!), but will cause the +encoding to miss any length between 3 and this value, so that the compression +may be worse (but this can vary too depending on the image, sometimes it is +even a bit better instead). +The HASH_NUM_VALUES is the amount of unique possible hash values that +combinations of bytes can give, the higher it is the more memory is needed, but +if it's too low the advantage of hashing is gone. +*/ + +typedef struct Hash +{ + int* head; /*hash value to head circular pos*/ + int* val; /*circular pos to hash value*/ + /*circular pos to prev circular pos*/ + unsigned short* chain; + unsigned short* zeros; +} Hash; + +static unsigned hash_init(Hash* hash, unsigned windowsize) +{ + unsigned i; + hash->head = (int*)mymalloc(sizeof(int) * HASH_NUM_VALUES); + hash->val = (int*)mymalloc(sizeof(int) * windowsize); + hash->chain = (unsigned short*)mymalloc(sizeof(unsigned short) * windowsize); + hash->zeros = (unsigned short*)mymalloc(sizeof(unsigned short) * windowsize); + + if(!hash->head || !hash->val || !hash->chain || !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*/ + + return 0; +} + +static void hash_cleanup(Hash* hash) +{ + myfree(hash->head); + myfree(hash->val); + myfree(hash->chain); + myfree(hash->zeros); +} + +static unsigned getHash(const unsigned char* data, size_t size, size_t pos) +{ + unsigned result = 0; + size_t amount, i; + if(pos >= size) return 0; + amount = HASH_NUM_CHARACTERS; + if(pos + amount >= size) amount = size - pos; + for(i = 0; i < amount; i++) result ^= (data[pos + i] << (i * HASH_SHIFT)); + return result % HASH_NUM_VALUES; +} + +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++; + return data - start; +} + +static void updateHashChain(Hash* hash, + size_t pos, int hashval, unsigned windowsize) +{ + unsigned wpos = pos % windowsize; + hash->val[wpos] = hashval; + if(hash->head[hashval] != -1) + { + hash->chain[wpos] = hash->head[hashval]; + } + hash->head[hashval] = wpos; +} + +/*Enable to use lazy instead of greedy matching. It looks one byte further +to see if that one gives a longer distance. This gives slightly better compression, at the cost +of a speed loss.*/ +#define LAZY_MATCHING + +/* +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 short numzeros = 0; + int usezeros = windowsize >= 8192; /*for small window size, the 'max chain length' optimization does a better job*/ + unsigned pos, i, error = 0; + + if(!error) + { + unsigned offset; /*the offset represents the distance in LZ77 terminology*/ + unsigned length; +#ifdef LAZY_MATCHING + unsigned lazy = 0; + unsigned lazylength = 0, lazyoffset = 0; +#endif /*LAZY_MATCHING*/ + unsigned hashval; + unsigned current_offset, current_length; + const unsigned char *lastptr, *foreptr, *backptr; + unsigned short hashpos, prevpos; + + for(pos = inpos; pos < insize; pos++) + { + size_t wpos = pos % windowsize; /*position for in 'circular' hash buffers*/ + + hashval = getHash(in, insize, pos); + updateHashChain(hash, pos, hashval, windowsize); + + if(usezeros && hashval == 0) + { + numzeros = countZeros(in, insize, pos); + hash->zeros[wpos] = numzeros; + } + + /*the length and offset found for the current position*/ + length = 0; + offset = 0; + + prevpos = hash->head[hashval]; + hashpos = hash->chain[prevpos]; + + lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH]; + + /*search for the longest string*/ + if(hash->val[wpos] == (int)hashval) + { + /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/ + unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8; + for(;;) + { + /*stop when went completely around the circular buffer*/ + if(prevpos < wpos && hashpos > prevpos && hashpos <= wpos) break; + if(prevpos > wpos && (hashpos <= wpos || hashpos > prevpos)) break; + if(maxchainlength-- == 0) break; + + current_offset = hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize; + 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(usezeros && hashval == 0 && hash->val[hashpos] == 0 /*hashval[hashpos] may be out of date*/) + { + unsigned short skip = hash->zeros[hashpos]; + if(skip > numzeros) skip = numzeros; + backptr += skip; + foreptr += skip; + } + + /* multiple checks at once per array bounds check */ + 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)*/ + if(current_length == MAX_SUPPORTED_DEFLATE_LENGTH) break; + } + } + + if(hashpos == hash->chain[hashpos]) break; + + prevpos = hashpos; + hashpos = hash->chain[hashpos]; + } + } + +#ifdef LAZY_MATCHING + if(!lazy && length >= 3 && length < MAX_SUPPORTED_DEFLATE_LENGTH) + { + lazy = 1; + lazylength = length; + lazyoffset = offset; + continue; + } + 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*/ + pos--; + } + } +#endif /*LAZY_MATCHING*/ + + 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 == 3 && offset > 2048) + { + /*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 + 0])) ERROR_BREAK(83 /*alloc fail*/); + if(!uivector_push_back(out, in[pos + 1])) ERROR_BREAK(83 /*alloc fail*/); + if(!uivector_push_back(out, in[pos + 2])) ERROR_BREAK(83 /*alloc fail*/); + } + else + { + addLengthDistance(out, length, offset); + } + for(i = 1; i < length; i++) + { + pos++; + hashval = getHash(in, insize, pos); + updateHashChain(hash, pos, hashval, windowsize); + if(usezeros && hashval == 0) + { + hash->zeros[pos % windowsize] = countZeros(in, insize, pos); + } + } + } + + } /*end of the loop through each character of input*/ + } /*end of "if(!error)"*/ + + 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, j, numdeflateblocks = (datasize + 65534) / 65535; + unsigned datapos = 0; + for(i = 0; i < numdeflateblocks; i++) + { + unsigned BFINAL, BTYPE, LEN, NLEN; + unsigned char firstbyte; + + BFINAL = (i == numdeflateblocks - 1); + BTYPE = 0; + + firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1) << 1) + ((BTYPE & 2) << 1)); + ucvector_push_back(out, firstbyte); + + LEN = 65535; + if(datasize - datapos < 65535) LEN = (unsigned)datasize - datapos; + NLEN = 65535 - LEN; + + ucvector_push_back(out, (unsigned char)(LEN % 256)); + ucvector_push_back(out, (unsigned char)(LEN / 256)); + ucvector_push_back(out, (unsigned char)(NLEN % 256)); + ucvector_push_back(out, (unsigned char)(NLEN / 256)); + + /*Decompressed data*/ + for(j = 0; j < 65535 && datapos < datasize; j++) + { + ucvector_push_back(out, data[datapos++]); + } + } + + 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(size_t* bp, ucvector* out, 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]; + addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_ll, val), HuffmanTree_getLength(tree_ll, 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]; + + addBitsToStream(bp, out, length_extra_bits, n_length_extra_bits); + addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_d, distance_code), + HuffmanTree_getLength(tree_d, distance_code)); + addBitsToStream(bp, out, 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(ucvector* out, size_t* bp, Hash* hash, + const unsigned char* data, size_t datapos, size_t dataend, + const LodePNGCompressSettings* settings, int 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 lenghts 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*/ + uivector frequencies_ll; /*frequency of lit,len codes*/ + uivector frequencies_d; /*frequency of dist codes*/ + uivector frequencies_cl; /*frequency of code length codes*/ + uivector bitlen_lld; /*lit,len,dist code lenghts (int bits), literally (without repeat codes).*/ + uivector bitlen_lld_e; /*bitlen_lld encoded with repeat codes (this is a rudemtary run length compression)*/ + /*bitlen_cl is the code length code lengths ("clcl"). The bit lengths of codes to represent tree_cl + (these are written as is in the file, it would be crazy to compress these using yet another huffman + tree that needs to be represented by yet another set of code lengths)*/ + uivector bitlen_cl; + size_t datasize = dataend - datapos; + + /* + Due to the huffman compression of huffman tree representations ("two levels"), there are some anologies: + 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 numcodes_ll, numcodes_d, i; + unsigned HLIT, HDIST, HCLEN; + + uivector_init(&lz77_encoded); + HuffmanTree_init(&tree_ll); + HuffmanTree_init(&tree_d); + HuffmanTree_init(&tree_cl); + uivector_init(&frequencies_ll); + uivector_init(&frequencies_d); + uivector_init(&frequencies_cl); + uivector_init(&bitlen_lld); + uivector_init(&bitlen_lld_e); + uivector_init(&bitlen_cl); + + /*This while loop is 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) + { + if(settings->use_lz77) + { + error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize); /*LZ77 encoded*/ + 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] = data[i]; /*no LZ77, but still will be Huffman compressed*/ + } + + if(!uivector_resizev(&frequencies_ll, 286, 0)) ERROR_BREAK(83 /*alloc fail*/); + if(!uivector_resizev(&frequencies_d, 30, 0)) ERROR_BREAK(83 /*alloc fail*/); + + /*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.data[symbol]++; + if(symbol > 256) + { + unsigned dist = lz77_encoded.data[i + 2]; + frequencies_d.data[dist]++; + i += 3; + } + } + frequencies_ll.data[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.data, frequencies_ll.size, 15); + if(error) break; + error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d.data, frequencies_d.size, 15); + if(error) break; + + numcodes_ll = tree_ll.numcodes; if(numcodes_ll > 286) numcodes_ll = 286; + numcodes_d = tree_d.numcodes; if(numcodes_d > 30) numcodes_d = 30; + /*store the code lengths of both generated trees in bitlen_lld*/ + for(i = 0; i < numcodes_ll; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_ll, (unsigned)i)); + for(i = 0; i < numcodes_d; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_d, (unsigned)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 < (unsigned)bitlen_lld.size; i++) + { + unsigned j = 0; /*amount of repititions*/ + while(i + j + 1 < (unsigned)bitlen_lld.size && bitlen_lld.data[i + j + 1] == bitlen_lld.data[i]) j++; + + if(bitlen_lld.data[i] == 0 && j >= 2) /*repeat code for zeroes*/ + { + j++; /*include the first zero*/ + if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ + { + uivector_push_back(&bitlen_lld_e, 17); + uivector_push_back(&bitlen_lld_e, j - 3); + } + else /*repeat code 18 supports max 138 zeroes*/ + { + if(j > 138) j = 138; + uivector_push_back(&bitlen_lld_e, 18); + uivector_push_back(&bitlen_lld_e, j - 11); + } + i += (j - 1); + } + else if(j >= 3) /*repeat code for value other than zero*/ + { + size_t k; + unsigned num = j / 6, rest = j % 6; + uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]); + for(k = 0; k < num; k++) + { + uivector_push_back(&bitlen_lld_e, 16); + uivector_push_back(&bitlen_lld_e, 6 - 3); + } + if(rest >= 3) + { + uivector_push_back(&bitlen_lld_e, 16); + uivector_push_back(&bitlen_lld_e, rest - 3); + } + else j -= rest; + i += j; + } + else /*too short to benefit from repeat code*/ + { + uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]); + } + } + + /*generate tree_cl, the huffmantree of huffmantrees*/ + + if(!uivector_resizev(&frequencies_cl, NUM_CODE_LENGTH_CODES, 0)) ERROR_BREAK(83 /*alloc fail*/); + for(i = 0; i < bitlen_lld_e.size; i++) + { + frequencies_cl.data[bitlen_lld_e.data[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.data[i] >= 16) i++; + } + + error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl.data, frequencies_cl.size, 7); + if(error) break; + + if(!uivector_resize(&bitlen_cl, NUM_CODE_LENGTH_CODES)) ERROR_BREAK(83 /*alloc fail*/); + for(i = 0; i < NUM_CODE_LENGTH_CODES; i++) + { + /*lenghts of code length tree is in the order as specified by deflate*/ + bitlen_cl.data[i] = HuffmanTree_getLength(&tree_cl, CLCL_ORDER[i]); + } + while(bitlen_cl.data[bitlen_cl.size - 1] == 0 && bitlen_cl.size > 4) + { + /*remove zeros at the end, but minimum size must be 4*/ + if(!uivector_resize(&bitlen_cl, bitlen_cl.size - 1)) ERROR_BREAK(83 /*alloc fail*/); + } + if(error) break; + + /* + 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 lenghts 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*/ + addBitToStream(bp, out, BFINAL); + addBitToStream(bp, out, 0); /*first bit of BTYPE "dynamic"*/ + addBitToStream(bp, out, 1); /*second bit of BTYPE "dynamic"*/ + + /*write the HLIT, HDIST and HCLEN values*/ + HLIT = (unsigned)(numcodes_ll - 257); + HDIST = (unsigned)(numcodes_d - 1); + HCLEN = (unsigned)bitlen_cl.size - 4; + addBitsToStream(bp, out, HLIT, 5); + addBitsToStream(bp, out, HDIST, 5); + addBitsToStream(bp, out, HCLEN, 4); + + /*write the code lenghts of the code length alphabet*/ + for(i = 0; i < HCLEN + 4; i++) addBitsToStream(bp, out, bitlen_cl.data[i], 3); + + /*write the lenghts of the lit/len AND the dist alphabet*/ + for(i = 0; i < bitlen_lld_e.size; i++) + { + addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_cl, bitlen_lld_e.data[i]), + HuffmanTree_getLength(&tree_cl, bitlen_lld_e.data[i])); + /*extra bits of repeat codes*/ + if(bitlen_lld_e.data[i] == 16) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 2); + else if(bitlen_lld_e.data[i] == 17) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 3); + else if(bitlen_lld_e.data[i] == 18) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 7); + } + + /*write the compressed data symbols*/ + writeLZ77data(bp, out, &lz77_encoded, &tree_ll, &tree_d); + /*error: the length of the end code 256 must be larger than 0*/ + if(HuffmanTree_getLength(&tree_ll, 256) == 0) ERROR_BREAK(64); + + /*write the end code*/ + addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 256)); + + break; /*end of error-while*/ + } + + /*cleanup*/ + uivector_cleanup(&lz77_encoded); + HuffmanTree_cleanup(&tree_ll); + HuffmanTree_cleanup(&tree_d); + HuffmanTree_cleanup(&tree_cl); + uivector_cleanup(&frequencies_ll); + uivector_cleanup(&frequencies_d); + uivector_cleanup(&frequencies_cl); + uivector_cleanup(&bitlen_lld_e); + uivector_cleanup(&bitlen_lld); + uivector_cleanup(&bitlen_cl); + + return error; +} + +static unsigned deflateFixed(ucvector* out, size_t* bp, Hash* hash, + const unsigned char* data, + size_t datapos, size_t dataend, + const LodePNGCompressSettings* settings, int 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); + + generateFixedLitLenTree(&tree_ll); + generateFixedDistanceTree(&tree_d); + + addBitToStream(bp, out, BFINAL); + addBitToStream(bp, out, 1); /*first bit of BTYPE*/ + addBitToStream(bp, out, 0); /*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); + if(!error) writeLZ77data(bp, out, &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++) + { + addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, data[i]), HuffmanTree_getLength(&tree_ll, data[i])); + } + } + /*add END code*/ + if(!error) addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 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) +{ +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 2 + if(settings->custom_encoder) + { + unsigned char** out2 = &out->data; + size_t* outsize = &out->size; + + unsigned error = lodepng_custom_deflate(out2, outsize, in, insize, settings); + + if(!error) ucvector_init_buffer(out, *out2, *outsize); + return error; + } + else + { +#endif /*LODEPNG_CUSTOM_ZLIB_ENCODER == 2*/ + unsigned error = 0; + size_t i, blocksize, numdeflateblocks; + size_t bp = 0; /*the bit pointer*/ + Hash hash; + + if(settings->btype > 2) return 61; + + if(settings->btype == 0) return deflateNoCompression(out, in, insize); + + if(settings->btype == 1) blocksize = insize; + else /*if(settings->btype == 2)*/ + { + blocksize = insize / 8 + 8; + if(blocksize < 65535) blocksize = 65535; + } + + numdeflateblocks = (insize + blocksize - 1) / blocksize; + if(numdeflateblocks == 0) numdeflateblocks = 1; + + error = hash_init(&hash, settings->windowsize); + if(error) return error; + + for(i = 0; i < numdeflateblocks && !error; i++) + { + int 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(out, &bp, &hash, in, start, end, settings, final); + else if(settings->btype == 2) error = deflateDynamic(out, &bp, &hash, in, start, end, settings, final); + } + + hash_cleanup(&hash); + + return error; +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 2 + } +#endif /*LODEPNG_CUSTOM_ZLIB_ENCODER == 2*/ +} + +unsigned lodepng_deflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGCompressSettings* settings) +{ + unsigned error; + ucvector v; + ucvector_init_buffer(&v, *out, *outsize); + error = lodepng_deflatev(&v, in, insize, settings); + *out = v.data; + *outsize = v.size; + return error; +} + +#endif /*LODEPNG_COMPILE_DECODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Adler32 */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) +{ + unsigned s1 = adler & 0xffff; + unsigned s2 = (adler >> 16) & 0xffff; + + while(len > 0) + { + /*at least 5550 sums can be done before the sums overflow, saving a lot of module divisions*/ + unsigned amount = len > 5550 ? 5550 : len; + len -= amount; + while(amount > 0) + { + s1 = (s1 + *data++); + s2 = (s2 + s1); + amount--; + } + s1 %= 65521; + s2 %= 65521; + } + + return (s2 << 16) | s1; +} + +/*Return the adler32 of the bytes data[0..len-1]*/ +static unsigned adler32(const unsigned char* data, unsigned len) +{ + return update_adler32(1L, data, len); +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Zlib / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_DECODER + +unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGDecompressSettings* settings) +{ +#if LODEPNG_CUSTOM_ZLIB_DECODER == 1 + if(settings->custom_decoder) + { + return lodepng_custom_zlib_decompress(out, outsize, in, insize, settings); + } + else + { +#endif /*LODEPNG_CUSTOM_ZLIB_DECODER == 1*/ + 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 = lodepng_inflate(out, outsize, in + 2, insize - 2, settings); + if(error) return error; + + if(!settings->ignore_adler32) + { + unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]); + unsigned checksum = adler32(*out, (unsigned)(*outsize)); + if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/ + } + + return 0; /*no error*/ +#if LODEPNG_CUSTOM_ZLIB_DECODER == 1 + } +#endif /*LODEPNG_CUSTOM_ZLIB_DECODER == 1*/ +} + +#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) +{ +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 1 + if(settings->custom_encoder) + { + return lodepng_custom_zlib_compress(out, outsize, in, insize, settings); + } + else + { +#endif /*LODEPNG_CUSTOM_ZLIB_ENCODER == 1*/ + /*initially, *out must be NULL and outsize 0, if you just give some random *out + that's pointing to a non allocated buffer, this'll crash*/ + ucvector deflatedata, outv; + size_t i; + unsigned error; + + unsigned ADLER32; + /*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; + + /*ucvector-controlled version of the output buffer, for dynamic array*/ + ucvector_init_buffer(&outv, *out, *outsize); + + ucvector_push_back(&outv, (unsigned char)(CMFFLG / 256)); + ucvector_push_back(&outv, (unsigned char)(CMFFLG % 256)); + + ucvector_init(&deflatedata); + error = lodepng_deflatev(&deflatedata, in, insize, settings); + + if(!error) + { + ADLER32 = adler32(in, (unsigned)insize); + for(i = 0; i < deflatedata.size; i++) ucvector_push_back(&outv, deflatedata.data[i]); + ucvector_cleanup(&deflatedata); + lodepng_add32bitInt(&outv, ADLER32); + } + + *out = outv.data; + *outsize = outv.size; + + return error; +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 1 + } +#endif /*LODEPNG_CUSTOM_ZLIB_ENCODER == 1*/ +} + +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#else /*no LODEPNG_COMPILE_ZLIB*/ + +#ifdef LODEPNG_COMPILE_DECODER +static unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGDecompressSettings* settings) +{ + return lodepng_custom_zlib_decompress(out, outsize, in, insize, settings); +} +#endif /*LODEPNG_COMPILE_DECODER*/ +#ifdef LODEPNG_COMPILE_ENCODER +static unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGCompressSettings* settings) +{ + return lodepng_custom_zlib_compress(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; +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 0 + settings->custom_encoder = 0; +#else + settings->custom_encoder = 1; +#endif +} + +#if LODEPNG_CUSTOM_ZLIB_ENCODER == 0 +const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 0}; +#else +const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 1}; +#endif + + +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#ifdef LODEPNG_COMPILE_DECODER + +void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) +{ + settings->ignore_adler32 = 0; +#if LODEPNG_CUSTOM_ZLIB_DECODER == 0 + settings->custom_decoder = 0; +#else + settings->custom_decoder = 1; +#endif +} + +#if LODEPNG_CUSTOM_ZLIB_DECODER == 0 +const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0}; +#else +const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 1}; +#endif + +#endif /*LODEPNG_COMPILE_DECODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // End of Zlib related code. Begin of PNG related code. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_PNG + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / CRC32 / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static unsigned Crc32_crc_table_computed = 0; +static unsigned Crc32_crc_table[256]; + +/*Make the table for a fast CRC.*/ +static void Crc32_make_crc_table(void) +{ + unsigned c, k, n; + for(n = 0; n < 256; n++) + { + c = n; + for(k = 0; k < 8; k++) + { + if(c & 1) c = 0xedb88320L ^ (c >> 1); + else c = c >> 1; + } + Crc32_crc_table[n] = c; + } + Crc32_crc_table_computed = 1; +} + +/*Update a running CRC with the bytes buf[0..len-1]--the CRC should be +initialized to all 1's, and the transmitted value is the 1's complement of the +final running CRC (see the crc() routine below).*/ +static unsigned Crc32_update_crc(const unsigned char* buf, unsigned crc, size_t len) +{ + unsigned c = crc; + size_t n; + + if(!Crc32_crc_table_computed) Crc32_make_crc_table(); + for(n = 0; n < len; n++) + { + c = Crc32_crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8); + } + return c; +} + +/*Return the CRC of the bytes buf[0..len-1].*/ +unsigned lodepng_crc32(const unsigned char* buf, size_t len) +{ + return Crc32_update_crc(buf, 0xffffffffL, len) ^ 0xffffffffL; +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Reading and writing single bits and bytes from/to stream for LodePNG / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +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; +} + +static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) +{ + unsigned result = 0; + size_t i; + for(i = nbits - 1; i < nbits; i--) + { + result += (unsigned)readBitFromReversedStream(bitpointer, bitstream) << i; + } + return result; +} + +#ifdef LODEPNG_COMPILE_DECODER +static void setBitOfReversedStream0(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) +{ + /*the current bit in bitstream must be 0 for this to work*/ + if(bit) + { + /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/ + bitstream[(*bitpointer) >> 3] |= (bit << (7 - ((*bitpointer) & 0x7))); + } + (*bitpointer)++; +} +#endif /*LODEPNG_COMPILE_DECODER*/ + +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) >> 3] &= (unsigned char)(~(1 << (7 - ((*bitpointer) & 0x7)))); + else bitstream[(*bitpointer) >> 3] |= (1 << (7 - ((*bitpointer) & 0x7))); + (*bitpointer)++; +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / PNG chunks / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +unsigned lodepng_chunk_length(const unsigned char* chunk) +{ + return lodepng_read32bitInt(&chunk[0]); +} + +void lodepng_chunk_type(char type[5], const unsigned char* chunk) +{ + unsigned i; + for(i = 0; i < 4; i++) type[i] = chunk[4 + i]; + type[4] = 0; /*null termination char*/ +} + +unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) +{ + if(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 total_chunk_length = lodepng_chunk_length(chunk) + 12; + return &chunk[total_chunk_length]; +} + +const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk) +{ + unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12; + return &chunk[total_chunk_length]; +} + +unsigned lodepng_chunk_append(unsigned char** out, size_t* outlength, const unsigned char* chunk) +{ + unsigned i; + unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12; + unsigned char *chunk_start, *new_buffer; + size_t new_length = (*outlength) + total_chunk_length; + if(new_length < total_chunk_length || new_length < (*outlength)) return 77; /*integer overflow happened*/ + + new_buffer = (unsigned char*)myrealloc(*out, new_length); + if(!new_buffer) return 83; /*alloc fail*/ + (*out) = new_buffer; + (*outlength) = 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; +} + +unsigned lodepng_chunk_create(unsigned char** out, size_t* outlength, unsigned length, + const char* type, const unsigned char* data) +{ + unsigned i; + unsigned char *chunk, *new_buffer; + size_t new_length = (*outlength) + length + 12; + if(new_length < length + 12 || new_length < (*outlength)) return 77; /*integer overflow happened*/ + new_buffer = (unsigned char*)myrealloc(*out, new_length); + if(!new_buffer) return 83; /*alloc fail*/ + (*out) = new_buffer; + (*outlength) = new_length; + chunk = &(*out)[(*outlength) - length - 12]; + + /*1: length*/ + lodepng_set32bitInt(chunk, (unsigned)length); + + /*2: chunk name (4 letters)*/ + chunk[4] = type[0]; + chunk[5] = type[1]; + chunk[6] = type[2]; + chunk[7] = type[3]; + + /*3: the data*/ + for(i = 0; i < length; i++) chunk[8 + i] = data[i]; + + /*4: CRC (of the chunkname characters and the data)*/ + lodepng_chunk_generate_crc(chunk); + + return 0; +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Color types and such / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/*return type is a LodePNG error code*/ +static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) /*bd = bitdepth*/ +{ + switch(colortype) + { + case 0: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; /*grey*/ + case 2: if(!( bd == 8 || bd == 16)) return 37; break; /*RGB*/ + case 3: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break; /*palette*/ + case 4: if(!( bd == 8 || bd == 16)) return 37; break; /*grey + alpha*/ + case 6: if(!( bd == 8 || bd == 16)) return 37; break; /*RGBA*/ + default: return 31; + } + return 0; /*allowed color type / bits combination*/ +} + +static unsigned getNumColorChannels(LodePNGColorType colortype) +{ + switch(colortype) + { + case 0: return 1; /*grey*/ + case 2: return 3; /*RGB*/ + case 3: return 1; /*palette*/ + case 4: return 2; /*grey + alpha*/ + case 6: return 4; /*RGBA*/ + } + return 0; /*unexisting 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; +} + +void lodepng_color_mode_cleanup(LodePNGColorMode* info) +{ + lodepng_palette_clear(info); +} + +unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) +{ + size_t i; + lodepng_color_mode_cleanup(dest); + *dest = *source; + if(source->palette) + { + dest->palette = (unsigned char*)mymalloc(source->palettesize * 4); + if(!dest->palette && source->palettesize) return 83; /*alloc fail*/ + for(i = 0; i < source->palettesize * 4; i++) dest->palette[i] = source->palette[i]; + } + return 0; +} + +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) myfree(info->palette); + info->palettesize = 0; +} + +unsigned lodepng_palette_add(LodePNGColorMode* info, + unsigned char r, unsigned char g, unsigned char b, unsigned char a) +{ + unsigned char* data; + /*the same resize technique as C++ std::vectors is used, and here it's made so that for a palette with + the max of 256 colors, it'll have the exact alloc size*/ + if(!(info->palettesize & (info->palettesize - 1))) /*if palettesize is 0 or a power of two*/ + { + /*allocated data must be at least 4* palettesize (for 4 color bytes)*/ + size_t alloc_size = info->palettesize == 0 ? 4 : info->palettesize * 4 * 2; + data = (unsigned char*)myrealloc(info->palette, alloc_size); + if(!data) return 83; /*alloc fail*/ + else info->palette = data; + } + 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; +} + +unsigned lodepng_get_bpp(const LodePNGColorMode* info) +{ + /*calculate bits per pixel out of colortype and bitdepth*/ + 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); +} + +size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) +{ + return (w * h * lodepng_get_bpp(color) + 7) / 8; +} + +size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) +{ + return (w * h * lodepng_get_bpp_lct(colortype, bitdepth) + 7) / 8; +} + +#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++) myfree(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*)mymalloc(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]); + } + myfree(info->text_keys); + myfree(info->text_strings); +} + +static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) +{ + size_t i = 0; + dest->text_keys = 0; + dest->text_strings = 0; + 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; +} + +void lodepng_clear_text(LodePNGInfo* info) +{ + LodePNGText_cleanup(info); +} + +unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) +{ + char** new_keys = (char**)(myrealloc(info->text_keys, sizeof(char*) * (info->text_num + 1))); + char** new_strings = (char**)(myrealloc(info->text_strings, sizeof(char*) * (info->text_num + 1))); + if(!new_keys || !new_strings) + { + myfree(new_keys); + myfree(new_strings); + return 83; /*alloc fail*/ + } + + info->text_num++; + info->text_keys = new_keys; + info->text_strings = new_strings; + + string_init(&info->text_keys[info->text_num - 1]); + string_set(&info->text_keys[info->text_num - 1], key); + + string_init(&info->text_strings[info->text_num - 1]); + string_set(&info->text_strings[info->text_num - 1], str); + + return 0; +} + +/******************************************************************************/ + +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]); + } + myfree(info->itext_keys); + myfree(info->itext_langtags); + myfree(info->itext_transkeys); + myfree(info->itext_strings); +} + +static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) +{ + size_t i = 0; + dest->itext_keys = 0; + dest->itext_langtags = 0; + dest->itext_transkeys = 0; + dest->itext_strings = 0; + 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); +} + +unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag, + const char* transkey, const char* str) +{ + char** new_keys = (char**)(myrealloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1))); + char** new_langtags = (char**)(myrealloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1))); + char** new_transkeys = (char**)(myrealloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1))); + char** new_strings = (char**)(myrealloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1))); + if(!new_keys || !new_langtags || !new_transkeys || !new_strings) + { + myfree(new_keys); + myfree(new_langtags); + myfree(new_transkeys); + myfree(new_strings); + return 83; /*alloc fail*/ + } + + info->itext_num++; + info->itext_keys = new_keys; + info->itext_langtags = new_langtags; + info->itext_transkeys = new_transkeys; + info->itext_strings = new_strings; + + string_init(&info->itext_keys[info->itext_num - 1]); + string_set(&info->itext_keys[info->itext_num - 1], key); + + string_init(&info->itext_langtags[info->itext_num - 1]); + string_set(&info->itext_langtags[info->itext_num - 1], langtag); + + string_init(&info->itext_transkeys[info->itext_num - 1]); + string_set(&info->itext_transkeys[info->itext_num - 1], transkey); + + string_init(&info->itext_strings[info->itext_num - 1]); + string_set(&info->itext_strings[info->itext_num - 1], str); + + return 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; + + 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); + + LodePNGUnknownChunks_cleanup(info); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +} + +unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) +{ + lodepng_info_cleanup(dest); + *dest = *source; + 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)); + + LodePNGUnknownChunks_init(dest); + CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source)); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + return 0; +} + +void lodepng_info_swap(LodePNGInfo* a, LodePNGInfo* b) +{ + LodePNGInfo temp = *a; + *a = *b; + *b = temp; +} + +/* ////////////////////////////////////////////////////////////////////////// */ + +/*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) +{ + /*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 % (8 / bits); + in &= (1 << bits) - 1; /*filter out any other bits of the input value*/ + in = in << (bits * (8 / bits - p - 1)); + if(p == 0) out[index * bits / 8] = in; + else out[index * bits / 8] |= 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 a bit like an octree for RGB bits, except that a node has 256 +children and there is one level of the tree per color channel. This may use more memory +than an octree, but this is only used to count up to 256 so it's good enough. +*/ +struct ColorTree +{ + ColorTree* next; /*null, or array of 256 pointers to ColorTree of next level*/ + int index; /*the payload. Only has a meaningful value if this is in the 4th level*/ +}; + +static void color_tree_make_next(ColorTree* tree); + +/*next: whether to create the next array or not*/ +static void color_tree_init(ColorTree* tree, int next) +{ + if(next) color_tree_make_next(tree); + else tree->next = 0; + tree->index = -1; +} + +static void color_tree_make_next(ColorTree* tree) +{ + int i; + tree->next = (ColorTree*)mymalloc(256 * sizeof(ColorTree)); + for(i = 0; i < 256; i++) color_tree_init(&tree->next[i], 0); +} + +static void color_tree_cleanup(ColorTree* tree) +{ + if(tree->next) + { + int i; + for(i = 0; i < 256; i++) color_tree_cleanup(&tree->next[i]); + myfree(tree->next); + } +} + +/*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) +{ + tree = &tree->next[r]; + if(tree->next == 0) return -1; + tree = &tree->next[g]; + if(tree->next == 0) return -1; + tree = &tree->next[b]; + if(tree->next == 0) return -1; + tree = &tree->next[a]; + + return tree->index; +} + +#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")*/ +static void color_tree_add(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a, int index) +{ + tree = &tree->next[r]; + if(tree->next == 0) color_tree_make_next(tree); + tree = &tree->next[g]; + if(tree->next == 0) color_tree_make_next(tree); + tree = &tree->next[b]; + if(tree->next == 0) color_tree_make_next(tree); + tree = &tree->next[a]; + + tree->index = index; +} + +/*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 grey = r; /*((unsigned short)r + g + b) / 3*/; + if(mode->bitdepth == 8) out[i] = grey; + else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = grey; + else + { + /*take the most significant bits of grey*/ + grey = (grey >> (8 - mode->bitdepth)) & ((1 << mode->bitdepth) - 1); + addColorBits(out, i, mode->bitdepth, grey); + } + } + 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, index); + } + else if(mode->colortype == LCT_GREY_ALPHA) + { + unsigned char grey = r; /*((unsigned short)r + g + b) / 3*/; + if(mode->bitdepth == 8) + { + out[i * 2 + 0] = grey; + out[i * 2 + 1] = a; + } + else if(mode->bitdepth == 16) + { + out[i * 4 + 0] = out[i * 4 + 1] = grey; + 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 unsigned rgba16ToPixel(unsigned char* out, size_t i, + const LodePNGColorMode* mode, + unsigned short r, unsigned short g, unsigned short b, unsigned short a) +{ + if(mode->bitdepth != 16) return 85; /*must be 16 for this function*/ + if(mode->colortype == LCT_GREY) + { + unsigned short grey = r; /*((unsigned)r + g + b) / 3*/; + out[i * 2 + 0] = (grey >> 8) & 255; + out[i * 2 + 1] = grey & 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 grey = r; /*((unsigned)r + g + b) / 3*/; + out[i * 4 + 0] = (grey >> 8) & 255; + out[i * 4 + 1] = grey & 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; + } + + return 0; /*no error*/ +} + +/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/ +static unsigned 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); + } + if(index >= mode->palettesize) return 47; /*index out of 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]; + } + } + + return 0; /*no error*/ +} + +/*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 unsigned 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->bitdepth != 16) return 85; /*error: this function only supports 16-bit input*/ + + 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 = 256 * in[i * 6 + 0] + in[i * 6 + 1]; + *g = 256 * in[i * 6 + 2] + in[i * 6 + 3]; + *b = 256 * 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 = 256 * in[i * 4 + 0] + in[i * 4 + 1]; + *a = 256 * in[i * 4 + 2] + in[i * 4 + 3]; + } + else if(mode->colortype == LCT_RGBA) + { + *r = 256 * in[i * 8 + 0] + in[i * 8 + 1]; + *g = 256 * in[i * 8 + 2] + in[i * 8 + 3]; + *b = 256 * in[i * 8 + 4] + in[i * 8 + 5]; + *a = 256 * in[i * 8 + 6] + in[i * 8 + 7]; + } + else return 85; /*error: this function only supports 16-bit input*/ + + return 0; /*no error*/ +} + +/* +converts from any color type to 24-bit or 32-bit (later maybe more supported). return value = LodePNG error code +the out buffer must have (w * h * bpp + 7) / 8 bytes, where bpp is the bits per pixel of the output color type +(lodepng_get_bpp) for < 8 bpp images, there may _not_ be padding bits at the end of scanlines. +*/ +unsigned lodepng_convert(unsigned char* out, const unsigned char* in, + LodePNGColorMode* mode_out, LodePNGColorMode* mode_in, + unsigned w, unsigned h) +{ + unsigned error = 0; + size_t i; + ColorTree tree; + + if(lodepng_color_mode_equal(mode_out, mode_in)) + { + size_t numbytes = lodepng_get_raw_size(w, h, mode_in); + for(i = 0; i < numbytes; i++) out[i] = in[i]; + return error; + } + + if(mode_out->colortype == LCT_PALETTE) + { + size_t palsize = 1 << mode_out->bitdepth; + if(mode_out->palettesize < palsize) palsize = mode_out->palettesize; + color_tree_init(&tree, 1); + for(i = 0; i < palsize; i++) + { + unsigned char* p = &mode_out->palette[i * 4]; + color_tree_add(&tree, p[0], p[1], p[2], p[3], i); + } + } + + if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) + { + size_t numpixels = w * h; + for(i = 0; i < numpixels; i++) + { + unsigned short r = 0, g = 0, b = 0, a = 0; + error = getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + if(error) return error; + error = rgba16ToPixel(out, i, mode_out, r, g, b, a); + if(error) return error; + } + } + else + { + size_t numpixels = w * h; + for(i = 0; i < numpixels; i++) + { + unsigned char r = 0, g = 0, b = 0, a = 0; + error = getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); + if(error) return error; + error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a); + if(error) return error; + } + } + + if(mode_out->colortype == LCT_PALETTE) + { + color_tree_cleanup(&tree); + } + + return error; +} + +#ifdef LODEPNG_COMPILE_ENCODER + +typedef struct ColorProfile +{ + unsigned char sixteenbit; /*needs more than 8 bits per channel*/ + unsigned char sixteenbit_done; + + + unsigned char colored; /*not greyscale*/ + unsigned char colored_done; + + unsigned char key; /*a color key is required, or more*/ + unsigned short key_r; /*these values are always in 16-bit bitdepth in the profile*/ + unsigned short key_g; + unsigned short key_b; + unsigned char alpha; /*alpha channel, or alpha palette, required*/ + unsigned char alpha_done; + + unsigned numcolors; + ColorTree tree; /*for listing the counted colors, up to 256*/ + unsigned char* palette; /*size 1024. Remember up to the first 256 RGBA colors*/ + unsigned maxnumcolors; /*if more than that amount counted*/ + unsigned char numcolors_done; + + unsigned greybits; /*amount of bits required for greyscale (1, 2, 4, 8). Does not take 16 bit into account.*/ + unsigned char greybits_done; + +} ColorProfile; + +static void color_profile_init(ColorProfile* profile, LodePNGColorMode* mode) +{ + profile->sixteenbit = 0; + profile->sixteenbit_done = mode->bitdepth == 16 ? 0 : 1; + + profile->colored = 0; + profile->colored_done = lodepng_is_greyscale_type(mode) ? 1 : 0; + + profile->key = 0; + profile->alpha = 0; + profile->alpha_done = lodepng_can_have_alpha(mode) ? 0 : 1; + + profile->numcolors = 0; + color_tree_init(&profile->tree, 1); + profile->palette = (unsigned char*)mymalloc(1024); + profile->maxnumcolors = 257; + if(lodepng_get_bpp(mode) <= 8) + { + int bpp = lodepng_get_bpp(mode); + profile->maxnumcolors = bpp == 1 ? 2 : (bpp == 2 ? 4 : (bpp == 4 ? 16 : 256)); + } + profile->numcolors_done = 0; + + profile->greybits = 1; + profile->greybits_done = lodepng_get_bpp(mode) == 1 ? 1 : 0; +} + +static void color_profile_cleanup(ColorProfile* profile) +{ + color_tree_cleanup(&profile->tree); + myfree(profile->palette); +} + +/*function used for debug purposes with C++*/ +/*void printColorProfile(ColorProfile* p) +{ + std::cout << "sixteenbit: " << (int)p->sixteenbit << std::endl; + std::cout << "sixteenbit_done: " << (int)p->sixteenbit_done << std::endl; + std::cout << "colored: " << (int)p->colored << std::endl; + std::cout << "colored_done: " << (int)p->colored_done << std::endl; + std::cout << "key: " << (int)p->key << std::endl; + std::cout << "key_r: " << (int)p->key_r << std::endl; + std::cout << "key_g: " << (int)p->key_g << std::endl; + std::cout << "key_b: " << (int)p->key_b << std::endl; + std::cout << "alpha: " << (int)p->alpha << std::endl; + std::cout << "alpha_done: " << (int)p->alpha_done << std::endl; + std::cout << "numcolors: " << (int)p->numcolors << std::endl; + std::cout << "maxnumcolors: " << (int)p->maxnumcolors << std::endl; + std::cout << "numcolors_done: " << (int)p->numcolors_done << std::endl; + std::cout << "greybits: " << (int)p->greybits << std::endl; + std::cout << "greybits_done: " << (int)p->greybits_done << std::endl; +}*/ + +/*Returns how many bits needed to represent given value (max 8 bit)*/ +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; +} + +/*profile must already have been inited with mode. +It's ok to set some parameters of profile to done already.*/ +static unsigned get_color_profile(ColorProfile* profile, + const unsigned char* in, size_t numpixels, + LodePNGColorMode* mode) +{ + unsigned error = 0; + size_t i; + + if(mode->bitdepth == 16) + { + for(i = 0; i < numpixels; i++) + { + unsigned short r, g, b, a; + error = getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode); + if(error) break; + + /*a color is considered good for 8-bit if the first byte and the second byte are equal, + (so if it's divisible through 257), NOT necessarily if the second byte is 0*/ + if(!profile->sixteenbit_done + && (((r & 255) != ((r >> 8) & 255)) + || ((g & 255) != ((g >> 8) & 255)) + || ((b & 255) != ((b >> 8) & 255)))) + { + profile->sixteenbit = 1; + profile->sixteenbit_done = 1; + profile->greybits_done = 1; /*greybits is not applicable anymore at 16-bit*/ + profile->numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/ + } + + if(!profile->colored_done && (r != g || r != b)) + { + profile->colored = 1; + profile->colored_done = 1; + profile->greybits_done = 1; /*greybits is not applicable anymore*/ + } + + if(!profile->alpha_done && a != 255) + { + if(a == 0 && !(profile->key && (r != profile->key_r || g != profile->key_g || b != profile->key_b))) + { + if(!profile->key) + { + profile->key = 1; + profile->key_r = r; + profile->key_g = g; + profile->key_b = b; + } + } + else + { + profile->alpha = 1; + profile->alpha_done = 1; + profile->greybits_done = 1; /*greybits is not applicable anymore*/ + } + } + + if(!profile->greybits_done) + { + /*assuming 8-bit r, this test does not care about 16-bit*/ + unsigned bits = getValueRequiredBits(r); + if(bits > profile->greybits) profile->greybits = bits; + if(profile->greybits >= 8) profile->greybits_done = 1; + } + + if(!profile->numcolors_done) + { + /*assuming 8-bit rgba, this test does not care about 16-bit*/ + if(!color_tree_has(&profile->tree, r, g, b, a)) + { + color_tree_add(&profile->tree, r, g, b, a, profile->numcolors); + if(profile->numcolors < 256) + { + unsigned char* p = profile->palette; + unsigned i = profile->numcolors; + p[i * 4 + 0] = r; + p[i * 4 + 1] = g; + p[i * 4 + 2] = b; + p[i * 4 + 3] = a; + } + profile->numcolors++; + if(profile->numcolors >= profile->maxnumcolors) profile->numcolors_done = 1; + } + } + + if(profile->alpha_done && profile->numcolors_done + && profile->colored_done && profile->sixteenbit_done && profile->greybits_done) + { + break; + } + }; + } + else + { + for(i = 0; i < numpixels; i++) + { + unsigned char r, g, b, a; + error = getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode); + if(error) break; + + if(!profile->colored_done && (r != g || r != b)) + { + profile->colored = 1; + profile->colored_done = 1; + profile->greybits_done = 1; /*greybits is not applicable anymore*/ + } + + if(!profile->alpha_done && a != 255) + { + if(a == 0 && !(profile->key && (r != profile->key_r || g != profile->key_g || b != profile->key_b))) + { + if(!profile->key) + { + profile->key = 1; + profile->key_r = r; + profile->key_g = g; + profile->key_b = b; + } + } + else + { + profile->alpha = 1; + profile->alpha_done = 1; + profile->greybits_done = 1; /*greybits is not applicable anymore*/ + } + } + + if(!profile->greybits_done) + { + unsigned bits = getValueRequiredBits(r); + if(bits > profile->greybits) profile->greybits = bits; + if(profile->greybits >= 8) profile->greybits_done = 1; + } + + if(!profile->numcolors_done) + { + if(!color_tree_has(&profile->tree, r, g, b, a)) + { + + color_tree_add(&profile->tree, r, g, b, a, profile->numcolors); + if(profile->numcolors < 256) + { + unsigned char* p = profile->palette; + unsigned i = profile->numcolors; + p[i * 4 + 0] = r; + p[i * 4 + 1] = g; + p[i * 4 + 2] = b; + p[i * 4 + 3] = a; + } + profile->numcolors++; + if(profile->numcolors >= profile->maxnumcolors) profile->numcolors_done = 1; + } + } + + if(profile->alpha_done && profile->numcolors_done && profile->colored_done && profile->greybits_done) + { + break; + } + }; + } + + /*make the profile's key always 16-bit for consistency*/ + if(mode->bitdepth < 16) + { + /*repeat each byte twice*/ + profile->key_r *= 257; + profile->key_g *= 257; + profile->key_b *= 257; + } + + return error; +} + +/*updates values of mode with a potentially smaller color model. mode_out should +contain the user chosen color model, but will be overwritten with the new chosen one.*/ +static unsigned doAutoChooseColor(LodePNGColorMode* mode_out, + const unsigned char* image, unsigned w, unsigned h, LodePNGColorMode* mode_in, + LodePNGAutoConvert auto_convert) +{ + ColorProfile profile; + unsigned error = 0; + + if(auto_convert == LAC_ALPHA) + { + if(mode_out->colortype != LCT_RGBA && mode_out->colortype != LCT_GREY_ALPHA) return 0; + } + + color_profile_init(&profile, mode_in); + if(auto_convert == LAC_ALPHA) + { + profile.colored_done = 1; + profile.greybits_done = 1; + profile.numcolors_done = 1; + profile.sixteenbit_done = 1; + } + error = get_color_profile(&profile, image, w * h, mode_in); + + if(!error && auto_convert == LAC_ALPHA) + { + if(!profile.alpha) + { + mode_out->colortype = (mode_out->colortype == LCT_RGBA ? LCT_RGB : LCT_GREY); + } + } + else if(!error && auto_convert != LAC_ALPHA) + { + mode_out->key_defined = 0; + + if(profile.sixteenbit) + { + mode_out->bitdepth = 16; + if(profile.alpha) + { + mode_out->colortype = profile.colored ? LCT_RGBA : LCT_GREY_ALPHA; + } + else + { + mode_out->colortype = profile.colored ? LCT_RGB : LCT_GREY; + if(profile.key) + { + mode_out->key_defined = 1; + mode_out->key_r = profile.key_r; + mode_out->key_g = profile.key_g; + mode_out->key_b = profile.key_b; + } + } + } + else /*less than 16 bits per channel*/ + { + /*don't add palette overhead if image hasn't got a lot of pixels*/ + unsigned n = profile.numcolors; + int palette_ok = n <= 256 && (n * 2 < w * h); + unsigned palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8)); + int grey_ok = !profile.colored && !profile.alpha; /*grey without alpha, with potentially low bits*/ + if(palette_ok || grey_ok) + { + if(!palette_ok || (grey_ok && profile.greybits <= palettebits)) + { + mode_out->colortype = LCT_GREY; + mode_out->bitdepth = profile.greybits; + if(profile.key) + { + unsigned keyval = profile.key_r; + keyval &= (profile.greybits - 1); /*same subgroup of bits repeated, so taking right bits is fine*/ + mode_out->key_defined = 1; + mode_out->key_r = keyval; + mode_out->key_g = keyval; + mode_out->key_b = keyval; + } + } + else + { + /*fill in the palette*/ + unsigned i; + unsigned char* p = profile.palette; + for(i = 0; i < profile.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; + } + } + else /*8-bit per channel*/ + { + mode_out->bitdepth = 8; + if(profile.alpha) + { + mode_out->colortype = profile.colored ? LCT_RGBA : LCT_GREY_ALPHA; + } + else + { + mode_out->colortype = profile.colored ? LCT_RGB : LCT_GREY /*LCT_GREY normally won't occur, already done earlier*/; + if(profile.key) + { + mode_out->key_defined = 1; + mode_out->key_r = profile.key_r % 256; + mode_out->key_g = profile.key_g % 256; + mode_out->key_b = profile.key_b % 256; + } + } + } + } + } + + color_profile_cleanup(&profile); + + if(mode_out->colortype == LCT_PALETTE && mode_in->palettesize == mode_out->palettesize) + { + /*In this case keep the palette order of the input, so that the user can choose an optimal one*/ + size_t i; + for(i = 0; i < mode_in->palettesize * 4; i++) + { + mode_out->palette[i] = mode_in->palette[i]; + } + } + + if(auto_convert == LAC_AUTO_NO_NIBBLES && mode_out->bitdepth < 8) + { + /*palette can keep its small amount of colors, as long as no indices use it*/ + mode_out->bitdepth = 8; + } + + return error; +} + +#endif /* #ifdef LODEPNG_COMPILE_ENCODER */ + +/* +Paeth predicter, used by PNG filter type 4 +The parameters are of type short, but should come from unsigned chars, the shorts +are only needed to make the paeth calculation correct. +*/ +static unsigned char paethPredictor(short a, short b, short c) +{ + short pa = abs(b - c); + short pb = abs(a - c); + short pc = abs(a + b - c - c); + + if(pc < pa && pc < pb) return (unsigned char)c; + else if(pb < pa) return (unsigned char)b; + else return (unsigned char)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*/ + +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] * (1 + (passw[i] * bpp + 7) / 8) : 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 + 7) / 8); + /*only padded at end of reduced image*/ + passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7) / 8; + } +} + +#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) +{ + LodePNGInfo* info = &state->info_png; + if(insize == 0 || in == 0) + { + CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/ + } + if(insize < 29) + { + 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*/ + 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(in[12] != 'I' || in[13] != 'H' || in[14] != 'D' || in[15] != 'R') + { + CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/ + } + + /*read the values given in the header*/ + *w = lodepng_read32bitInt(&in[16]); + *h = lodepng_read32bitInt(&in[20]); + 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]; + + 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*/ + } + } + + /*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); + + state->error = checkColorValidity(info->color.colortype, info->color.bitdepth); + 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: + for(i = 0; i < bytewidth; i++) recon[i] = scanline[i]; + for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth]; + 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) + { + for(i = 0; i < bytewidth; i++) recon[i] = scanline[i] + precon[i] / 2; + for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) / 2); + } + else + { + for(i = 0; i < bytewidth; i++) recon[i] = scanline[i]; + for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth] / 2; + } + break; + case 4: + if(precon) + { + for(i = 0; i < bytewidth; i++) + { + recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/ + } + for(i = bytewidth; i < length; i++) + { + recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth])); + } + } + else + { + for(i = 0; i < bytewidth; i++) + { + recon[i] = scanline[i]; + } + for(i = bytewidth; i < length; i++) + { + /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/ + recon[i] = (scanline[i] + recon[i - bytewidth]); + } + } + break; + default: return 36; /*error: unexisting 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 + 7) / 8; + size_t linebytes = (w * bpp + 7) / 8; + + 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; +} + +static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) +{ + /*Note: this function works on image buffers WITHOUT padding bits at end of scanlines + with non-multiple-of-8 bit amounts, only between reduced images is padding + 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)*/ + 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 / 8; + 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] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + 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] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp; + for(b = 0; b < bpp; b++) + { + unsigned char bit = readBitFromReversedStream(&ibp, in); + /*note that this function assumes the out buffer is completely 0, use setBitOfReversedStream otherwise*/ + setBitOfReversedStream0(&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 (= posible 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 + 7) / 8) * 8) + { + CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp)); + removePaddingBits(out, in, w * bpp, ((w * bpp + 7) / 8) * 8, h); + } + /*we can immediatly 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 + 7) / 8) * 8, passh[i]); + } + } + + Adam7_deinterlace(out, in, w, h, bpp); + } + + return 0; +} + +/*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; + size_t i; + ucvector idat; /*the data from idat chunks*/ + + /*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*/ + + /*provide some proper output values if error will happen*/ + *out = 0; + + state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/ + if(state->error) return; + + ucvector_init(&idat); + 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*/ + + /*error: size of the in buffer too small to contain next chunk*/ + if((size_t)((chunk - in) + 12) > insize || chunk < in) CERROR_BREAK(state->error, 30); + + /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/ + chunkLength = lodepng_chunk_length(chunk); + /*error: chunk length larger than the max PNG chunk size*/ + if(chunkLength > 2147483647) CERROR_BREAK(state->error, 63); + + if((size_t)((chunk - in) + chunkLength + 12) > insize || (chunk + chunkLength + 12) < in) + { + CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk*/ + } + + data = lodepng_chunk_data_const(chunk); + + /*IDAT chunk, containing compressed image data*/ + if(lodepng_chunk_type_equals(chunk, "IDAT")) + { + size_t oldsize = idat.size; + if(!ucvector_resize(&idat, oldsize + chunkLength)) CERROR_BREAK(state->error, 83 /*alloc fail*/); + for(i = 0; i < chunkLength; i++) idat.data[oldsize + i] = data[i]; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + critical_pos = 3; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } + /*IEND chunk*/ + else if(lodepng_chunk_type_equals(chunk, "IEND")) + { + IEND = 1; + } + /*palette chunk (PLTE)*/ + else if(lodepng_chunk_type_equals(chunk, "PLTE")) + { + unsigned pos = 0; + if(state->info_png.color.palette) myfree(state->info_png.color.palette); + state->info_png.color.palettesize = chunkLength / 3; + state->info_png.color.palette = (unsigned char*)mymalloc(4 * state->info_png.color.palettesize); + if(!state->info_png.color.palette && state->info_png.color.palettesize) + { + state->info_png.color.palettesize = 0; + CERROR_BREAK(state->error, 83); /*alloc fail*/ + } + if(state->info_png.color.palettesize > 256) CERROR_BREAK(state->error, 38); /*error: palette too big*/ + + for(i = 0; i < state->info_png.color.palettesize; i++) + { + state->info_png.color.palette[4 * i + 0] = data[pos++]; /*R*/ + state->info_png.color.palette[4 * i + 1] = data[pos++]; /*G*/ + state->info_png.color.palette[4 * i + 2] = data[pos++]; /*B*/ + state->info_png.color.palette[4 * i + 3] = 255; /*alpha*/ + } +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + critical_pos = 2; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } + /*palette transparency chunk (tRNS)*/ + else if(lodepng_chunk_type_equals(chunk, "tRNS")) + { + if(state->info_png.color.colortype == LCT_PALETTE) + { + /*error: more alpha values given than there are palette entries*/ + if(chunkLength > state->info_png.color.palettesize) CERROR_BREAK(state->error, 38); + + for(i = 0; i < chunkLength; i++) state->info_png.color.palette[4 * i + 3] = data[i]; + } + else if(state->info_png.color.colortype == LCT_GREY) + { + /*error: this chunk must be 2 bytes for greyscale image*/ + if(chunkLength != 2) CERROR_BREAK(state->error, 30); + + state->info_png.color.key_defined = 1; + state->info_png.color.key_r = state->info_png.color.key_g + = state->info_png.color.key_b = 256 * data[0] + data[1]; + } + else if(state->info_png.color.colortype == LCT_RGB) + { + /*error: this chunk must be 6 bytes for RGB image*/ + if(chunkLength != 6) CERROR_BREAK(state->error, 41); + + state->info_png.color.key_defined = 1; + state->info_png.color.key_r = 256 * data[0] + data[1]; + state->info_png.color.key_g = 256 * data[2] + data[3]; + state->info_png.color.key_b = 256 * data[4] + data[5]; + } + else CERROR_BREAK(state->error, 42); /*error: tRNS chunk not allowed for other color models*/ + } +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + /*background color chunk (bKGD)*/ + else if(lodepng_chunk_type_equals(chunk, "bKGD")) + { + if(state->info_png.color.colortype == LCT_PALETTE) + { + /*error: this chunk must be 1 byte for indexed color image*/ + if(chunkLength != 1) CERROR_BREAK(state->error, 43); + + state->info_png.background_defined = 1; + state->info_png.background_r = state->info_png.background_g = state->info_png.background_b = data[0]; + } + else if(state->info_png.color.colortype == LCT_GREY || state->info_png.color.colortype == LCT_GREY_ALPHA) + { + /*error: this chunk must be 2 bytes for greyscale image*/ + if(chunkLength != 2) CERROR_BREAK(state->error, 44); + + state->info_png.background_defined = 1; + state->info_png.background_r = state->info_png.background_g = state->info_png.background_b + = 256 * data[0] + data[1]; + } + else if(state->info_png.color.colortype == LCT_RGB || state->info_png.color.colortype == LCT_RGBA) + { + /*error: this chunk must be 6 bytes for greyscale image*/ + if(chunkLength != 6) CERROR_BREAK(state->error, 45); + + state->info_png.background_defined = 1; + state->info_png.background_r = 256 * data[0] + data[1]; + state->info_png.background_g = 256 * data[2] + data[3]; + state->info_png.background_b = 256 * data[4] + data[5]; + } + } + /*text chunk (tEXt)*/ + else if(lodepng_chunk_type_equals(chunk, "tEXt")) + { + if(state->decoder.read_text_chunks) + { + char *key = 0, *str = 0; + + while(!state->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++; + /*error, end reached, no null terminator?*/ + if(length + 1 >= chunkLength) CERROR_BREAK(state->error, 75); + + key = (char*)mymalloc(length + 1); + if(!key) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i < length; i++) key[i] = data[i]; + + string2_begin = length + 1; + /*error, end reached, no null terminator?*/ + if(string2_begin > chunkLength) CERROR_BREAK(state->error, 75); + + length = chunkLength - string2_begin; + str = (char*)mymalloc(length + 1); + if(!str) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + str[length] = 0; + for(i = 0; i < length; i++) str[i] = data[string2_begin + i]; + + state->error = lodepng_add_text(&state->info_png, key, str); + + break; + } + + myfree(key); + myfree(str); + } + } + /*compressed text chunk (zTXt)*/ + else if(lodepng_chunk_type_equals(chunk, "zTXt")) + { + if(state->decoder.read_text_chunks) + { + unsigned length, string2_begin; + char *key = 0; + ucvector decoded; + + ucvector_init(&decoded); + + while(!state->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(state->error, 75); /*no null termination, corrupt?*/ + + key = (char*)mymalloc(length + 1); + if(!key) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i < length; i++) key[i] = data[i]; + + if(data[length + 1] != 0) CERROR_BREAK(state->error, 72); /*the 0 byte indicating compression must be 0*/ + + string2_begin = length + 2; + if(string2_begin > chunkLength) CERROR_BREAK(state->error, 75); /*no null termination, corrupt?*/ + + length = chunkLength - string2_begin; + state->error = lodepng_zlib_decompress(&decoded.data, &decoded.size, + (unsigned char*)(&data[string2_begin]), + length, &state->decoder.zlibsettings); + if(state->error) break; + ucvector_push_back(&decoded, 0); + + state->error = lodepng_add_text(&state->info_png, key, (char*)decoded.data); + + break; + } + + myfree(key); + ucvector_cleanup(&decoded); + if(state->error) break; + } + } + /*international text chunk (iTXt)*/ + else if(lodepng_chunk_type_equals(chunk, "iTXt")) + { + if(state->decoder.read_text_chunks) + { + unsigned length, begin, compressed; + char *key = 0, *langtag = 0, *transkey = 0; + ucvector decoded; + ucvector_init(&decoded); + + while(!state->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(state->error, 30); /*iTXt chunk too short*/ + + /*read the key*/ + for(length = 0; length < chunkLength && data[length] != 0; length++) ; + if(length + 2 >= chunkLength) CERROR_BREAK(state->error, 75); /*no null termination char found*/ + + key = (char*)mymalloc(length + 1); + if(!key) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i < length; i++) key[i] = data[i]; + + /*read the compression method*/ + compressed = data[length + 1]; + if(data[length + 2] != 0) CERROR_BREAK(state->error, 72); /*the 0 byte indicating compression must be 0*/ + + /*read the langtag*/ + begin = length + 3; + length = 0; + for(i = begin; i < chunkLength && data[i] != 0; i++) length++; + if(begin + length + 1 >= chunkLength) CERROR_BREAK(state->error, 75); /*no null termination char found*/ + + langtag = (char*)mymalloc(length + 1); + if(!langtag) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + langtag[length] = 0; + for(i = 0; i < length; i++) langtag[i] = data[begin + i]; + + /*read the transkey*/ + begin += length + 1; + length = 0; + for(i = begin; i < chunkLength && data[i] != 0; i++) length++; + if(begin + length + 1 >= chunkLength) CERROR_BREAK(state->error, 75); /*no null termination, corrupt?*/ + + transkey = (char*)mymalloc(length + 1); + if(!transkey) CERROR_BREAK(state->error, 83); /*alloc fail*/ + + transkey[length] = 0; + for(i = 0; i < length; i++) transkey[i] = data[begin + i]; + + /*read the actual text*/ + begin += length + 1; + if(begin > chunkLength) CERROR_BREAK(state->error, 75); /*no null termination, corrupt?*/ + + length = chunkLength - begin; + + if(compressed) + { + state->error = lodepng_zlib_decompress(&decoded.data, &decoded.size, + (unsigned char*)(&data[begin]), + length, &state->decoder.zlibsettings); + if(state->error) break; + if(decoded.allocsize < decoded.size) decoded.allocsize = decoded.size; + ucvector_push_back(&decoded, 0); + } + else + { + if(!ucvector_resize(&decoded, length + 1)) CERROR_BREAK(state->error, 83 /*alloc fail*/); + + decoded.data[length] = 0; + for(i = 0; i < length; i++) decoded.data[i] = data[begin + i]; + } + + state->error = lodepng_add_itext(&state->info_png, key, langtag, transkey, (char*)decoded.data); + + break; + } + + myfree(key); + myfree(langtag); + myfree(transkey); + ucvector_cleanup(&decoded); + if(state->error) break; + } + } + else if(lodepng_chunk_type_equals(chunk, "tIME")) + { + if(chunkLength != 7) CERROR_BREAK(state->error, 73); /*invalid tIME chunk size*/ + + state->info_png.time_defined = 1; + state->info_png.time.year = 256 * data[0] + data[+ 1]; + state->info_png.time.month = data[2]; + state->info_png.time.day = data[3]; + state->info_png.time.hour = data[4]; + state->info_png.time.minute = data[5]; + state->info_png.time.second = data[6]; + } + else if(lodepng_chunk_type_equals(chunk, "pHYs")) + { + if(chunkLength != 9) CERROR_BREAK(state->error, 74); /*invalid pHYs chunk size*/ + + state->info_png.phys_defined = 1; + state->info_png.phys_x = 16777216 * data[0] + 65536 * data[1] + 256 * data[2] + data[3]; + state->info_png.phys_y = 16777216 * data[4] + 65536 * data[5] + 256 * data[6] + data[7]; + state->info_png.phys_unit = data[8]; + } +#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(!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); + } + + if(!state->error) + { + ucvector scanlines; + ucvector_init(&scanlines); + + /*maximum final image length is already reserved in the vector's length - this is not really necessary*/ + if(!ucvector_resize(&scanlines, lodepng_get_raw_size(*w, *h, &state->info_png.color) + *h)) + { + state->error = 83; /*alloc fail*/ + } + if(!state->error) + { + /*decompress with the Zlib decompressor*/ + state->error = lodepng_zlib_decompress(&scanlines.data, &scanlines.size, idat.data, + idat.size, &state->decoder.zlibsettings); + } + + if(!state->error) + { + ucvector outv; + ucvector_init(&outv); + if(!ucvector_resizev(&outv, + lodepng_get_raw_size(*w, *h, &state->info_png.color), 0)) state->error = 83; /*alloc fail*/ + if(!state->error) state->error = postProcessScanlines(outv.data, scanlines.data, *w, *h, &state->info_png); + *out = outv.data; + } + ucvector_cleanup(&scanlines); + } + + ucvector_cleanup(&idat); +} + +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; sort of copy of the data*/ + unsigned char* data = *out; + size_t outsize; + + /*TODO: check if this works according to the statement in the documentation: "The converter can convert + from greyscale input color type, to 8-bit greyscale or greyscale 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*)mymalloc(outsize); + if(!(*out)) + { + state->error = 83; /*alloc fail*/ + } + else state->error = lodepng_convert(*out, data, &state->info_raw, &state->info_png.color, *w, *h); + myfree(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; + 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; + size_t buffersize; + unsigned error; + error = lodepng_load_file(&buffer, &buffersize, filename); + if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth); + myfree(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; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + settings->ignore_crc = 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 / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/*chunkName must be string of 4 characters*/ +static unsigned addChunk(ucvector* out, const char* chunkName, const unsigned char* data, size_t length) +{ + CERROR_TRY_RETURN(lodepng_chunk_create(&out->data, &out->size, (unsigned)length, chunkName, data)); + out->allocsize = out->size; /*fix the allocsize again*/ + return 0; +} + +static void writeSignature(ucvector* out) +{ + /*8 bytes PNG signature, aka the magic bytes*/ + ucvector_push_back(out, 137); + ucvector_push_back(out, 80); + ucvector_push_back(out, 78); + ucvector_push_back(out, 71); + ucvector_push_back(out, 13); + ucvector_push_back(out, 10); + ucvector_push_back(out, 26); + ucvector_push_back(out, 10); +} + +static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h, + LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) +{ + unsigned error = 0; + ucvector header; + ucvector_init(&header); + + lodepng_add32bitInt(&header, w); /*width*/ + lodepng_add32bitInt(&header, h); /*height*/ + ucvector_push_back(&header, (unsigned char)bitdepth); /*bit depth*/ + ucvector_push_back(&header, (unsigned char)colortype); /*color type*/ + ucvector_push_back(&header, 0); /*compression method*/ + ucvector_push_back(&header, 0); /*filter method*/ + ucvector_push_back(&header, interlace_method); /*interlace method*/ + + error = addChunk(out, "IHDR", header.data, header.size); + ucvector_cleanup(&header); + + return error; +} + +static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) +{ + unsigned error = 0; + size_t i; + ucvector PLTE; + ucvector_init(&PLTE); + for(i = 0; i < info->palettesize * 4; i++) + { + /*add all channels except alpha channel*/ + if(i % 4 != 3) ucvector_push_back(&PLTE, info->palette[i]); + } + error = addChunk(out, "PLTE", PLTE.data, PLTE.size); + ucvector_cleanup(&PLTE); + + return error; +} + +static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) +{ + unsigned error = 0; + size_t i; + ucvector tRNS; + ucvector_init(&tRNS); + if(info->colortype == LCT_PALETTE) + { + size_t 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) amount--; + else break; + } + /*add only alpha channel*/ + for(i = 0; i < amount; i++) ucvector_push_back(&tRNS, info->palette[4 * i + 3]); + } + else if(info->colortype == LCT_GREY) + { + if(info->key_defined) + { + ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256)); + } + } + else if(info->colortype == LCT_RGB) + { + if(info->key_defined) + { + ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_g / 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_g % 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_b / 256)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_b % 256)); + } + } + + error = addChunk(out, "tRNS", tRNS.data, tRNS.size); + ucvector_cleanup(&tRNS); + + return error; +} + +static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize, + LodePNGCompressSettings* zlibsettings) +{ + ucvector zlibdata; + unsigned error = 0; + + /*compress with the Zlib compressor*/ + ucvector_init(&zlibdata); + error = lodepng_zlib_compress(&zlibdata.data, &zlibdata.size, data, datasize, zlibsettings); + if(!error) error = addChunk(out, "IDAT", zlibdata.data, zlibdata.size); + ucvector_cleanup(&zlibdata); + + return error; +} + +static unsigned addChunk_IEND(ucvector* out) +{ + unsigned error = 0; + error = addChunk(out, "IEND", 0, 0); + return error; +} + +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + +static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) +{ + unsigned error = 0; + size_t i; + ucvector text; + ucvector_init(&text); + for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&text, (unsigned char)keyword[i]); + ucvector_push_back(&text, 0); + for(i = 0; textstring[i] != 0; i++) ucvector_push_back(&text, (unsigned char)textstring[i]); + error = addChunk(out, "tEXt", text.data, text.size); + ucvector_cleanup(&text); + + return error; +} + +static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring, + LodePNGCompressSettings* zlibsettings) +{ + unsigned error = 0; + ucvector data, compressed; + size_t i, textsize = strlen(textstring); + + ucvector_init(&data); + ucvector_init(&compressed); + for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&data, (unsigned char)keyword[i]); + ucvector_push_back(&data, 0); /*0 termination char*/ + ucvector_push_back(&data, 0); /*compression method: 0*/ + + error = lodepng_zlib_compress(&compressed.data, &compressed.size, + (unsigned char*)textstring, textsize, zlibsettings); + if(!error) + { + for(i = 0; i < compressed.size; i++) ucvector_push_back(&data, compressed.data[i]); + error = addChunk(out, "zTXt", data.data, data.size); + } + + ucvector_cleanup(&compressed); + ucvector_cleanup(&data); + return error; +} + +static unsigned addChunk_iTXt(ucvector* out, unsigned compressed, const char* keyword, const char* langtag, + const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings) +{ + unsigned error = 0; + ucvector data; + size_t i, textsize = strlen(textstring); + + ucvector_init(&data); + + for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&data, (unsigned char)keyword[i]); + ucvector_push_back(&data, 0); /*null termination char*/ + ucvector_push_back(&data, compressed ? 1 : 0); /*compression flag*/ + ucvector_push_back(&data, 0); /*compression method*/ + for(i = 0; langtag[i] != 0; i++) ucvector_push_back(&data, (unsigned char)langtag[i]); + ucvector_push_back(&data, 0); /*null termination char*/ + for(i = 0; transkey[i] != 0; i++) ucvector_push_back(&data, (unsigned char)transkey[i]); + ucvector_push_back(&data, 0); /*null termination char*/ + + if(compressed) + { + ucvector compressed_data; + ucvector_init(&compressed_data); + error = lodepng_zlib_compress(&compressed_data.data, &compressed_data.size, + (unsigned char*)textstring, textsize, zlibsettings); + if(!error) + { + for(i = 0; i < compressed_data.size; i++) ucvector_push_back(&data, compressed_data.data[i]); + } + ucvector_cleanup(&compressed_data); + } + else /*not compressed*/ + { + for(i = 0; textstring[i] != 0; i++) ucvector_push_back(&data, (unsigned char)textstring[i]); + } + + if(!error) error = addChunk(out, "iTXt", data.data, data.size); + ucvector_cleanup(&data); + return error; +} + +static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) +{ + unsigned error = 0; + ucvector bKGD; + ucvector_init(&bKGD); + if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) + { + ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256)); + } + else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) + { + ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_g / 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_g % 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_b / 256)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_b % 256)); + } + else if(info->color.colortype == LCT_PALETTE) + { + ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256)); /*palette index*/ + } + + error = addChunk(out, "bKGD", bKGD.data, bKGD.size); + ucvector_cleanup(&bKGD); + + return error; +} + +static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) +{ + unsigned error = 0; + unsigned char* data = (unsigned char*)mymalloc(7); + if(!data) return 83; /*alloc fail*/ + data[0] = (unsigned char)(time->year / 256); + data[1] = (unsigned char)(time->year % 256); + data[2] = time->month; + data[3] = time->day; + data[4] = time->hour; + data[5] = time->minute; + data[6] = time->second; + error = addChunk(out, "tIME", data, 7); + myfree(data); + return error; +} + +static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) +{ + unsigned error = 0; + ucvector data; + ucvector_init(&data); + + lodepng_add32bitInt(&data, info->phys_x); + lodepng_add32bitInt(&data, info->phys_y); + ucvector_push_back(&data, info->phys_unit); + + error = addChunk(out, "pHYs", data.data, data.size); + ucvector_cleanup(&data); + + return error; +} + +#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*/ + if(prevline) + { + for(i = 0; i < bytewidth; i++) out[i] = scanline[i]; + for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth]; + } + else + { + 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] / 2; + for(i = bytewidth; i < length; i++) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) / 2); + } + else + { + for(i = 0; i < bytewidth; i++) out[i] = scanline[i]; + for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth] / 2; + } + 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; /*unexisting filter type given*/ + } +} + +static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, + const LodePNGColorMode* info, const LodePNGEncoderSettings* settings) +{ + /* + For PNG filter method 0 + out must be a buffer with as size: h + (w * h * bpp + 7) / 8, because there are + the scanlines with 1 extra byte per scanline + */ + + unsigned bpp = lodepng_get_bpp(info); + /*the width of a scanline in bytes, not including the filter type*/ + size_t linebytes = (w * bpp + 7) / 8; + /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ + size_t bytewidth = (bpp + 7) / 8; + const unsigned char* prevline = 0; + unsigned x, y; + unsigned error = 0; + /* + 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_HEURISTIC. Parts of it are used for filter strategies + LFS_MINSUM and LFS_ZERO. + */ + int heuristic_zero = info->colortype == LCT_PALETTE || info->bitdepth < 8; + + if(bpp == 0) return 31; /*error: invalid color type*/ + + if((!heuristic_zero && settings->filter_strategy == LFS_HEURISTIC)|| + settings->filter_strategy == LFS_MINSUM) + { + /*adaptive filtering*/ + size_t sum[5]; + ucvector attempt[5]; /*five filtering attempts, one for each filter type*/ + size_t smallest = 0; + unsigned type, bestType = 0; + + for(type = 0; type < 5; type++) ucvector_init(&attempt[type]); + + for(type = 0; type < 5; type++) + { + if(!ucvector_resize(&attempt[type], linebytes)) ERROR_BREAK(83 /*alloc fail*/); + } + + if(!error) + { + for(y = 0; y < h; y++) + { + /*try the 5 filter types*/ + for(type = 0; type < 5; type++) + { + filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type); + + /*calculate the sum of the result*/ + sum[type] = 0; + /*note that not all pixels are checked to speed this up while still having probably the best choice*/ + for(x = 0; x < attempt[type].size; x+=3) + { + /*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.*/ + if(type == 0) sum[type] += (unsigned char)(attempt[type].data[x]); + else + { + signed char s = (signed char)(attempt[type].data[x]); + sum[type] += s < 0 ? -s : 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[type] < smallest) + { + bestType = type; + smallest = sum[type]; + } + } + + 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].data[x]; + } + } + + for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]); + } + else if((heuristic_zero && settings->filter_strategy == LFS_HEURISTIC)|| + settings->filter_strategy == LFS_ZERO) + { + for(y = 0; y < h; y++) + { + size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ + size_t inindex = linebytes * y; + const unsigned TYPE = 0; + out[outindex] = TYPE; /*filter type byte*/ + filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, TYPE); + prevline = &in[inindex]; + } + } + else if(settings->filter_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 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 /*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]; + ucvector attempt[5]; /*five filtering attempts, one for each filter type*/ + size_t smallest = 0; + unsigned type = 0, bestType = 0; + unsigned char* dummy; + LodePNGCompressSettings zlibsettings = settings->zlibsettings; + /*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_encoder = 0; + for(type = 0; type < 5; type++) + { + ucvector_init(&attempt[type]); + ucvector_resize(&attempt[type], linebytes); /*todo: give error if resize failed*/ + } + for(y = 0; y < h; y++) /*try the 5 filter types*/ + { + for(type = 0; type < 5; type++) + { + unsigned testsize = attempt[type].size; + /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/ + + filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type); + size[type] = 0; + dummy = 0; + lodepng_zlib_compress(&dummy, &size[type], attempt[type].data, testsize, &zlibsettings); + myfree(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].data[x]; + } + for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]); + } + + 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); + } +} + +static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) +{ + /*Note: this function works on image buffers WITHOUT padding bits at end of scanlines with non-multiple-of-8 + bit amounts, only between reduced images is padding*/ + 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 / 8; + 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 (= posible 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 + 7) / 8)); /*image size plus an extra byte per scanline + possible padding bits*/ + *out = (unsigned char*)mymalloc(*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 + 7) / 8) * 8) + { + ucvector padded; + ucvector_init(&padded); + if(!ucvector_resize(&padded, h * ((w * bpp + 7) / 8))) error = 83; /*alloc fail*/ + if(!error) + { + addPaddingBits(padded.data, in, ((w * bpp + 7) / 8) * 8, w * bpp, h); + error = filter(*out, padded.data, w, h, &info_png->color, settings); + } + ucvector_cleanup(&padded); + } + else + { + /*we can immediatly 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 char* adam7 = (unsigned char*)mymalloc((h * w * bpp + 7) / 8); + if(!adam7 && ((h * w * bpp + 7) / 8)) error = 83; /*alloc fail*/ + + while(!error) /*not a real while loop, used to break out to cleanup to avoid a goto*/ + { + 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); + + *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/ + *out = (unsigned char*)mymalloc(*outsize); + if(!(*out) && (*outsize)) ERROR_BREAK(83 /*alloc fail*/); + + Adam7_interlace(adam7, in, w, h, bpp); + + for(i = 0; i < 7; i++) + { + if(bpp < 8) + { + ucvector padded; + ucvector_init(&padded); + if(!ucvector_resize(&padded, h * ((w * bpp + 7) / 8))) error = 83; /*alloc fail*/ + if(!error) + { + addPaddingBits(&padded.data[padded_passstart[i]], &adam7[passstart[i]], + ((passw[i] * bpp + 7) / 8) * 8, passw[i] * bpp, passh[i]); + error = filter(&(*out)[filter_passstart[i]], &padded.data[padded_passstart[i]], + passw[i], passh[i], &info_png->color, settings); + } + + ucvector_cleanup(&padded); + } + else + { + error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]], + passw[i], passh[i], &info_png->color, settings); + } + } + + break; + } + + myfree(adam7); + } + + return error; +} + +/* +palette must have 4 * palettesize bytes allocated, and given in format RGBARGBARGBARGBA... +returns 0 if the palette is opaque, +returns 1 if the palette has a single color with alpha 0 ==> color key +returns 2 if the palette is semi-translucent. +*/ +static unsigned getPaletteTranslucency(const unsigned char* palette, size_t palettesize) +{ + size_t i, key = 0; + unsigned r, g, b; /*the value of the color with alpha 0, so long as color keying is possible*/ + for(i = 0; i < palettesize; i++) + { + if(!key && palette[4 * i + 3] == 0) + { + r = palette[4 * i + 0]; g = palette[4 * i + 1]; b = palette[4 * i + 2]; + key = 1; + i = (size_t)(-1); /*restart from beginning, to detect earlier opaque colors with key's value*/ + } + else if(palette[4 * i + 3] != 255) return 2; + /*when key, no opaque RGB may have key's RGB*/ + else if(key && r == palette[i * 4 + 0] && g == palette[i * 4 + 1] && b == palette[i * 4 + 2]) return 2; + } + return key; +} + +#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); + } + return 0; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + +unsigned lodepng_encode(unsigned char** out, size_t* outsize, + const unsigned char* image, unsigned w, unsigned h, + LodePNGState* state) +{ + LodePNGInfo info; + ucvector outv; + unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/ + size_t datasize = 0; + + /*provide some proper output values if error will happen*/ + *out = 0; + *outsize = 0; + state->error = 0; + + lodepng_info_init(&info); + lodepng_info_copy(&info, &state->info_png); + + if((info.color.colortype == LCT_PALETTE || state->encoder.force_palette) + && (info.color.palettesize == 0 || info.color.palettesize > 256)) + { + state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/ + return state->error; + } + + if(state->encoder.auto_convert != LAC_NO) + { + state->error = doAutoChooseColor(&info.color, image, w, h, &state->info_raw, + state->encoder.auto_convert); + } + if(state->error) return state->error; + + if(state->encoder.zlibsettings.windowsize > 32768) + { + CERROR_RETURN_ERROR(state->error, 60); /*error: windowsize larger than allowed*/ + } + if(state->encoder.zlibsettings.btype > 2) + { + CERROR_RETURN_ERROR(state->error, 61); /*error: unexisting btype*/ + } + if(state->info_png.interlace_method > 1) + { + CERROR_RETURN_ERROR(state->error, 71); /*error: unexisting interlace mode*/ + } + /*error: unexisting color type given*/ + if((state->error = checkColorValidity(info.color.colortype, info.color.bitdepth))) return state->error; + /*error: unexisting color type given*/ + if((state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth))) return state->error; + + if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) + { + unsigned char* converted; + size_t size = (w * h * lodepng_get_bpp(&info.color) + 7) / 8; + + converted = (unsigned char*)mymalloc(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) preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder); + myfree(converted); + } + else preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder); + + ucvector_init(&outv); + while(!state->error) /*while only executed once, to break on error*/ + { +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + size_t i; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + /*write signature and chunks*/ + writeSignature(&outv); + /*IHDR*/ + addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method); +#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) break; + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + /*PLTE*/ + if(info.color.colortype == LCT_PALETTE) + { + addChunk_PLTE(&outv, &info.color); + } + if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) + { + addChunk_PLTE(&outv, &info.color); + } + /*tRNS*/ + if(info.color.colortype == LCT_PALETTE && getPaletteTranslucency(info.color.palette, info.color.palettesize) != 0) + { + addChunk_tRNS(&outv, &info.color); + } + if((info.color.colortype == LCT_GREY || info.color.colortype == LCT_RGB) && info.color.key_defined) + { + addChunk_tRNS(&outv, &info.color); + } +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + /*bKGD (must come between PLTE and the IDAt chunks*/ + if(info.background_defined) addChunk_bKGD(&outv, &info); + /*pHYs (must come before the IDAT chunks)*/ + if(info.phys_defined) addChunk_pHYs(&outv, &info); + + /*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) break; + } +#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) break; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + /*tIME*/ + if(info.time_defined) addChunk_tIME(&outv, &info.time); + /*tEXt and/or zTXt*/ + for(i = 0; i < info.text_num; i++) + { + if(strlen(info.text_keys[i]) > 79) + { + state->error = 66; /*text chunk too large*/ + break; + } + if(strlen(info.text_keys[i]) < 1) + { + state->error = 67; /*text chunk too small*/ + break; + } + if(state->encoder.text_compression) + addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings); + else + addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]); + } + /*LodePNG version id in text chunk*/ + if(state->encoder.add_id) + { + unsigned alread_added_id_text = 0; + for(i = 0; i < info.text_num; i++) + { + if(!strcmp(info.text_keys[i], "LodePNG")) + { + alread_added_id_text = 1; + break; + } + } + if(alread_added_id_text == 0) + addChunk_tEXt(&outv, "LodePNG", VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/ + } + /*iTXt*/ + for(i = 0; i < info.itext_num; i++) + { + if(strlen(info.itext_keys[i]) > 79) + { + state->error = 66; /*text chunk too large*/ + break; + } + if(strlen(info.itext_keys[i]) < 1) + { + state->error = 67; /*text chunk too small*/ + break; + } + 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); + } + + /*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) break; + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + /*IEND*/ + addChunk_IEND(&outv); + + break; /*this isn't really a while loop; no error happened so break out now!*/ + } + + lodepng_info_cleanup(&info); + myfree(data); + /*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); + myfree(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_strategy = LFS_HEURISTIC; + settings->auto_convert = LAC_AUTO; + 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"; + case 16: return "unexisting 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 big"; /*more than 256 colors*/ + case 39: return "more palette alpha values given in tRNS chunk than there are colors in the palette"; + case 40: return "tRNS chunk has wrong size for greyscale 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 greyscale image"; + case 45: return "bKGD chunk has wrong size for RGB image"; + /*Is the palette too small?*/ + case 46: return "a value in indexed image is larger than the palette size (bitdepth = 8)"; + /*Is the palette too small?*/ + case 47: return "a value in indexed image is larger than the palette size (bitdepth < 8)"; + /*the input data is empty, maybe a PNG file doesn't exist or is in the wrong path*/ + case 48: return "empty input or file doesn't exist"; + 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 lenghts. 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 greyscale conversion formula to the user.*/ + case 62: return "conversion from color to greyscale not supported"; + case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk"; /*(2^31-1)*/ + /*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 "unexisting interlace mode given to encoder (must be 0 or 1)"; + case 72: return "while decoding, unexisting 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"; + case 83: return "memory allocation failed"; + case 84: return "given image too small to contain all pixels to be encoded"; + case 85: return "internal color conversion bug"; + case 86: return "impossible offset in lz77 encoding (internal bug)"; + } + return "unknown error code"; +} +#endif /*LODEPNG_COMPILE_ERROR_TEXT*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // C++ Wrapper // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + + +#ifdef LODEPNG_COMPILE_CPP +namespace lodepng +{ + +#ifdef LODEPNG_COMPILE_DISK +void load_file(std::vector<unsigned char>& buffer, const std::string& filename) +{ + std::ifstream file(filename.c_str(), std::ios::in|std::ios::binary|std::ios::ate); + + /*get filesize*/ + std::streamsize size = 0; + if(file.seekg(0, std::ios::end).good()) size = file.tellg(); + if(file.seekg(0, std::ios::beg).good()) size -= file.tellg(); + + /*read contents of the file into the vector*/ + buffer.resize(size_t(size)); + if(size > 0) file.read((char*)(&buffer[0]), size); +} + +/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ +void save_file(const std::vector<unsigned char>& buffer, const std::string& filename) +{ + std::ofstream file(filename.c_str(), std::ios::out|std::ios::binary); + file.write(buffer.empty() ? 0 : (char*)&buffer[0], std::streamsize(buffer.size())); +} +#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 = lodepng_zlib_decompress(&buffer, &buffersize, in, insize, &settings); + if(buffer) + { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + myfree(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 = lodepng_zlib_compress(&buffer, &buffersize, in, insize, &settings); + if(buffer) + { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + myfree(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; + 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[0], &buffer[buffersize]); + myfree(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; + 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[0], &buffer[buffersize]); + myfree(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; + load_file(buffer, filename); + 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[0], &buffer[buffersize]); + myfree(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[0], &buffer[buffersize]); + myfree(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) 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*/ |