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Diffstat (limited to 'thirdparty/basis_universal/lodepng.cpp')
| -rw-r--r-- | thirdparty/basis_universal/lodepng.cpp | 6006 |
1 files changed, 6006 insertions, 0 deletions
diff --git a/thirdparty/basis_universal/lodepng.cpp b/thirdparty/basis_universal/lodepng.cpp new file mode 100644 index 0000000000..cf964d0555 --- /dev/null +++ b/thirdparty/basis_universal/lodepng.cpp @@ -0,0 +1,6006 @@ +/* +LodePNG version 20190210 + +Copyright (c) 2005-2019 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. +*/ + +#ifdef _MSC_VER +#pragma warning (disable : 4201) + +#ifndef BASISU_NO_ITERATOR_DEBUG_LEVEL +#if defined(_DEBUG) || defined(DEBUG) +#define _ITERATOR_DEBUG_LEVEL 1 +#define _SECURE_SCL 1 +#else +#define _SECURE_SCL 0 +#define _ITERATOR_DEBUG_LEVEL 0 +#endif +#endif +#endif + +#include "lodepng.h" + +#include <limits.h> /* LONG_MAX */ +#include <stdio.h> /* file handling */ +#include <stdlib.h> /* allocations */ + +#if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/ +#pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/ +#pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/ +#endif /*_MSC_VER */ + +const char* LODEPNG_VERSION_STRING = "20190210"; + +/* +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 "lodepng_" in front +of the name, so that you can easily change them to others related to your +platform if needed. Everything else in the code calls these. Pass +-DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out +#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and +define them in your own project's source files without needing to change +lodepng source code. Don't forget to remove "static" if you copypaste them +from here.*/ + +#ifdef LODEPNG_COMPILE_ALLOCATORS +static void* lodepng_malloc(size_t size) { +#ifdef LODEPNG_MAX_ALLOC + if(size > LODEPNG_MAX_ALLOC) return 0; +#endif + return malloc(size); +} + +static void* lodepng_realloc(void* ptr, size_t new_size) { +#ifdef LODEPNG_MAX_ALLOC + if(new_size > LODEPNG_MAX_ALLOC) return 0; +#endif + return realloc(ptr, new_size); +} + +static void lodepng_free(void* ptr) { + free(ptr); +} +#else /*LODEPNG_COMPILE_ALLOCATORS*/ +void* lodepng_malloc(size_t size); +void* lodepng_realloc(void* ptr, size_t new_size); +void lodepng_free(void* ptr); +#endif /*LODEPNG_COMPILE_ALLOCATORS*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // Tools for C, and common code for PNG and Zlib. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b)) +#define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b)) + +/* +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;\ +} + +/*Set error var to the error code, and return from the void function.*/ +#define CERROR_RETURN(errorvar, code){\ + errorvar = code;\ + return;\ +} + +/* +About uivector, ucvector and string: +-All of them wrap dynamic arrays or text strings in a similar way. +-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version. +-The string tools are made to avoid problems with compilers that declare things like strncat as deprecated. +-They're not used in the interface, only internally in this file as static functions. +-As with many other structs in this file, the init and cleanup functions serve as ctor and dtor. +*/ + +#ifdef LODEPNG_COMPILE_ZLIB +/*dynamic vector of unsigned ints*/ +typedef struct uivector { + unsigned* data; + size_t size; /*size in number of unsigned longs*/ + size_t allocsize; /*allocated size in bytes*/ +} uivector; + +static void uivector_cleanup(void* p) { + ((uivector*)p)->size = ((uivector*)p)->allocsize = 0; + lodepng_free(((uivector*)p)->data); + ((uivector*)p)->data = NULL; +} + +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned uivector_reserve(uivector* p, size_t allocsize) { + if(allocsize > p->allocsize) { + size_t newsize = (allocsize > p->allocsize * 2) ? allocsize : (allocsize * 3 / 2); + void* data = lodepng_realloc(p->data, newsize); + if(data) { + p->allocsize = newsize; + p->data = (unsigned*)data; + } + else return 0; /*error: not enough memory*/ + } + return 1; +} + +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned uivector_resize(uivector* p, size_t size) { + if(!uivector_reserve(p, size * sizeof(unsigned))) return 0; + p->size = size; + return 1; /*success*/ +} + +/*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; +} +#endif /*LODEPNG_COMPILE_ENCODER*/ +#endif /*LODEPNG_COMPILE_ZLIB*/ + +/* /////////////////////////////////////////////////////////////////////////// */ + +/*dynamic vector of unsigned chars*/ +typedef struct ucvector { + unsigned char* data; + size_t size; /*used size*/ + size_t allocsize; /*allocated size*/ +} ucvector; + +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned ucvector_reserve(ucvector* p, size_t allocsize) { + if(allocsize > p->allocsize) { + size_t newsize = (allocsize > p->allocsize * 2) ? allocsize : (allocsize * 3 / 2); + void* data = lodepng_realloc(p->data, newsize); + if(data) { + p->allocsize = newsize; + p->data = (unsigned char*)data; + } + else return 0; /*error: not enough memory*/ + } + return 1; +} + +/*returns 1 if success, 0 if failure ==> nothing done*/ +static unsigned ucvector_resize(ucvector* p, size_t size) { + if(!ucvector_reserve(p, size * sizeof(unsigned char))) return 0; + p->size = size; + return 1; /*success*/ +} + +#ifdef LODEPNG_COMPILE_PNG + +static void ucvector_cleanup(void* p) { + ((ucvector*)p)->size = ((ucvector*)p)->allocsize = 0; + lodepng_free(((ucvector*)p)->data); + ((ucvector*)p)->data = NULL; +} + +static void ucvector_init(ucvector* p) { + p->data = NULL; + p->size = p->allocsize = 0; +} +#endif /*LODEPNG_COMPILE_PNG*/ + +#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*/ + +#if (defined(LODEPNG_COMPILE_PNG) && defined(LODEPNG_COMPILE_ANCILLARY_CHUNKS)) || defined(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 /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ + + +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_PNG +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + +/*free string pointer and set it to NULL*/ +static void string_cleanup(char** out) { + lodepng_free(*out); + *out = NULL; +} + +/* dynamically allocates a new string with a copy of the null terminated input text */ +static char* alloc_string(const char* in) { + size_t insize = strlen(in); + char* out = (char*)lodepng_malloc(insize + 1); + if(out) { + size_t i; + for(i = 0; i != insize; ++i) { + out[i] = in[i]; + } + out[i] = 0; + } + return out; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +#endif /*LODEPNG_COMPILE_PNG*/ + +/* ////////////////////////////////////////////////////////////////////////// */ + +unsigned lodepng_read32bitInt(const unsigned char* buffer) { + return (unsigned)((buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]); +} + +#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER) +/*buffer must have at least 4 allocated bytes available*/ +static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) { + buffer[0] = (unsigned char)((value >> 24) & 0xff); + buffer[1] = (unsigned char)((value >> 16) & 0xff); + buffer[2] = (unsigned char)((value >> 8) & 0xff); + buffer[3] = (unsigned char)((value ) & 0xff); +} +#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ + +#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 + +/* returns negative value on error. This should be pure C compatible, so no fstat. */ +static long lodepng_filesize(const char* filename) { + FILE* file; + long size; + file = fopen(filename, "rb"); + if(!file) return -1; + + if(fseek(file, 0, SEEK_END) != 0) { + fclose(file); + return -1; + } + + size = ftell(file); + /* It may give LONG_MAX as directory size, this is invalid for us. */ + if(size == LONG_MAX) size = -1; + + fclose(file); + return size; +} + +/* load file into buffer that already has the correct allocated size. Returns error code.*/ +static unsigned lodepng_buffer_file(unsigned char* out, size_t size, const char* filename) { + FILE* file; + size_t readsize; + file = fopen(filename, "rb"); + if(!file) return 78; + + readsize = fread(out, 1, size, file); + fclose(file); + + if (readsize != size) return 78; + return 0; +} + +unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) { + long size = lodepng_filesize(filename); + if (size < 0) return 78; + *outsize = (size_t)size; + + *out = (unsigned char*)lodepng_malloc((size_t)size); + if(!(*out) && size > 0) return 83; /*the above malloc failed*/ + + return lodepng_buffer_file(*out, (size_t)size, filename); +} + +/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ +unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) { + FILE* file; + file = fopen(filename, "wb" ); + if(!file) return 79; + fwrite(buffer, 1, buffersize, file); + fclose(file); + return 0; +} + +#endif /*LODEPNG_COMPILE_DISK*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // End of common code and tools. Begin of Zlib related code. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_ZLIB +#ifdef LODEPNG_COMPILE_ENCODER +/*TODO: this ignores potential out of memory errors*/ +#define addBitToStream(/*size_t**/ bitpointer, /*ucvector**/ bitstream, /*unsigned char*/ bit){\ + /*add a new byte at the end*/\ + if(((*bitpointer) & 7) == 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++*/ +/* +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) { + lodepng_free(tree->tree2d); + lodepng_free(tree->tree1d); + lodepng_free(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*)lodepng_malloc(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 huffman 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); + /*oversubscribed, see comment in lodepng_error_text*/ + if(treepos > 2147483647 || treepos + 2 > tree->numcodes) return 55; + 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 error = 0; + unsigned bits, n; + + uivector_init(&blcount); + uivector_init(&nextcode); + + tree->tree1d = (unsigned*)lodepng_malloc(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*)lodepng_malloc(numcodes * sizeof(unsigned)); + if(!tree->lengths) return 83; /*alloc fail*/ + for(i = 0; i != numcodes; ++i) tree->lengths[i] = bitlen[i]; + tree->numcodes = (unsigned)numcodes; /*number of symbols*/ + tree->maxbitlen = maxbitlen; + return HuffmanTree_makeFromLengths2(tree); +} + +#ifdef LODEPNG_COMPILE_ENCODER + +/*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding", +Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/ + +/*chain node for boundary package merge*/ +typedef struct BPMNode { + int weight; /*the sum of all weights in this chain*/ + unsigned index; /*index of this leaf node (called "count" in the paper)*/ + struct BPMNode* tail; /*the next nodes in this chain (null if last)*/ + int in_use; +} BPMNode; + +/*lists of chains*/ +typedef struct BPMLists { + /*memory pool*/ + unsigned memsize; + BPMNode* memory; + unsigned numfree; + unsigned nextfree; + BPMNode** freelist; + /*two heads of lookahead chains per list*/ + unsigned listsize; + BPMNode** chains0; + BPMNode** chains1; +} BPMLists; + +/*creates a new chain node with the given parameters, from the memory in the lists */ +static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) { + unsigned i; + BPMNode* result; + + /*memory full, so garbage collect*/ + if(lists->nextfree >= lists->numfree) { + /*mark only those that are in use*/ + for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0; + for(i = 0; i != lists->listsize; ++i) { + BPMNode* node; + for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1; + for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1; + } + /*collect those that are free*/ + lists->numfree = 0; + for(i = 0; i != lists->memsize; ++i) { + if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i]; + } + lists->nextfree = 0; + } + + result = lists->freelist[lists->nextfree++]; + result->weight = weight; + result->index = index; + result->tail = tail; + return result; +} + +/*sort the leaves with stable mergesort*/ +static void bpmnode_sort(BPMNode* leaves, size_t num) { + BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num); + size_t width, counter = 0; + for(width = 1; width < num; width *= 2) { + BPMNode* a = (counter & 1) ? mem : leaves; + BPMNode* b = (counter & 1) ? leaves : mem; + size_t p; + for(p = 0; p < num; p += 2 * width) { + size_t q = (p + width > num) ? num : (p + width); + size_t r = (p + 2 * width > num) ? num : (p + 2 * width); + size_t i = p, j = q, k; + for(k = p; k < r; k++) { + if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++]; + else b[k] = a[j++]; + } + } + counter++; + } + if(counter & 1) memcpy(leaves, mem, sizeof(*leaves) * num); + lodepng_free(mem); +} + +/*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/ +static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) { + unsigned lastindex = lists->chains1[c]->index; + + if(c == 0) { + if(lastindex >= numpresent) return; + lists->chains0[c] = lists->chains1[c]; + lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0); + } else { + /*sum of the weights of the head nodes of the previous lookahead chains.*/ + int sum = lists->chains0[c - 1]->weight + lists->chains1[c - 1]->weight; + lists->chains0[c] = lists->chains1[c]; + if(lastindex < numpresent && sum > leaves[lastindex].weight) { + lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists->chains1[c]->tail); + return; + } + lists->chains1[c] = bpmnode_create(lists, sum, lastindex, lists->chains1[c - 1]); + /*in the end we are only interested in the chain of the last list, so no + need to recurse if we're at the last one (this gives measurable speedup)*/ + if(num + 1 < (int)(2 * numpresent - 2)) { + boundaryPM(lists, leaves, numpresent, c - 1, num); + boundaryPM(lists, leaves, numpresent, c - 1, num); + } + } +} + +unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, + size_t numcodes, unsigned maxbitlen) { + unsigned error = 0; + unsigned i; + size_t numpresent = 0; /*number of symbols with non-zero frequency*/ + BPMNode* leaves; /*the symbols, only those with > 0 frequency*/ + + if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/ + if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/ + + leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves)); + if(!leaves) return 83; /*alloc fail*/ + + for(i = 0; i != numcodes; ++i) { + if(frequencies[i] > 0) { + leaves[numpresent].weight = (int)frequencies[i]; + leaves[numpresent].index = i; + ++numpresent; + } + } + + for(i = 0; i != numcodes; ++i) lengths[i] = 0; + + /*ensure at least two present symbols. There should be at least one symbol + according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To + make these work as well ensure there are at least two symbols. The + Package-Merge code below also doesn't work correctly if there's only one + symbol, it'd give it the theoritical 0 bits but in practice zlib wants 1 bit*/ + if(numpresent == 0) { + lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/ + } else if(numpresent == 1) { + lengths[leaves[0].index] = 1; + lengths[leaves[0].index == 0 ? 1 : 0] = 1; + } else { + BPMLists lists; + BPMNode* node; + + bpmnode_sort(leaves, numpresent); + + lists.listsize = maxbitlen; + lists.memsize = 2 * maxbitlen * (maxbitlen + 1); + lists.nextfree = 0; + lists.numfree = lists.memsize; + lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory)); + lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*)); + lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); + lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); + if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/ + + if(!error) { + for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i]; + + bpmnode_create(&lists, leaves[0].weight, 1, 0); + bpmnode_create(&lists, leaves[1].weight, 2, 0); + + for(i = 0; i != lists.listsize; ++i) { + lists.chains0[i] = &lists.memory[0]; + lists.chains1[i] = &lists.memory[1]; + } + + /*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/ + for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i); + + for(node = lists.chains1[maxbitlen - 1]; node; node = node->tail) { + for(i = 0; i != node->index; ++i) ++lengths[leaves[i].index]; + } + } + + lodepng_free(lists.memory); + lodepng_free(lists.freelist); + lodepng_free(lists.chains0); + lodepng_free(lists.chains1); + } + + lodepng_free(leaves); + return error; +} + +/*Create the Huffman tree given the symbol frequencies*/ +static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, + size_t mincodes, size_t numcodes, unsigned maxbitlen) { + unsigned error = 0; + while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/ + tree->maxbitlen = maxbitlen; + tree->numcodes = (unsigned)numcodes; /*number of symbols*/ + tree->lengths = (unsigned*)lodepng_realloc(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*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); + if(!bitlen) return 83; /*alloc fail*/ + + /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/ + for(i = 0; i <= 143; ++i) bitlen[i] = 8; + for(i = 144; i <= 255; ++i) bitlen[i] = 9; + for(i = 256; i <= 279; ++i) bitlen[i] = 7; + for(i = 280; i <= 287; ++i) bitlen[i] = 8; + + error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15); + + lodepng_free(bitlen); + return error; +} + +/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/ +static unsigned generateFixedDistanceTree(HuffmanTree* tree) { + unsigned i, error = 0; + unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); + if(!bitlen) return 83; /*alloc fail*/ + + /*there are 32 distance codes, but 30-31 are unused*/ + for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5; + error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15); + + lodepng_free(bitlen); + return error; +} + +#ifdef LODEPNG_COMPILE_DECODER + +/* +returns the code, 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) + 14 > (inlength << 3)) 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; + + if((*bp) + HCLEN * 3 > (inlength << 3)) return 50; /*error: the bit pointer is or will go past the memory*/ + + HuffmanTree_init(&tree_cl); + + while(!error) { + /*read the code length codes out of 3 * (amount of code length codes) bits*/ + + bitlen_cl = (unsigned*)lodepng_malloc(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*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); + bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); + if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); + 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(i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ + + if((*bp + 2) > inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ + 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 + 3) > 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 + 7) > 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*/ + } + + lodepng_free(bitlen_cl); + lodepng_free(bitlen_ll); + lodepng_free(bitlen_d); + HuffmanTree_cleanup(&tree_cl); + + return error; +} + +/*inflate a block with dynamic of fixed Huffman tree*/ +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*/ { + /*ucvector_push_back would do the same, but for some reason the two lines below run 10% faster*/ + if(!ucvector_resize(out, (*pos) + 1)) 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 + numextrabits_l) > 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_d == (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 + numextrabits_d) > 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(!ucvector_resize(out, (*pos) + length)) ERROR_BREAK(83 /*alloc fail*/); + if (distance < length) { + for(forward = 0; forward < length; ++forward) { + out->data[(*pos)++] = out->data[backward++]; + } + } else { + memcpy(out->data + *pos, out->data + backward, length); + *pos += length; + } + } 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) { + size_t p; + unsigned LEN, NLEN, n, error = 0; + + /*go to first boundary of byte*/ + while(((*bp) & 0x7) != 0) ++(*bp); + p = (*bp) / 8; /*byte position*/ + + /*read LEN (2 bytes) and NLEN (2 bytes)*/ + if(p + 4 >= inlength) return 52; /*error, bit pointer will jump past memory*/ + LEN = in[p] + 256u * in[p + 1]; p += 2; + NLEN = in[p] + 256u * 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(!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 = 1u * readBitFromStream(&bp, in); + BTYPE += 2u * 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; + } + + return error; +} + +unsigned lodepng_inflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings) { + 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; +} + +static unsigned inflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGDecompressSettings* settings) { + if(settings->custom_inflate) { + return settings->custom_inflate(out, outsize, in, insize, settings); + } else { + return lodepng_inflate(out, outsize, in, insize, settings); + } +} + +#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) { + /*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/ + size_t left = 1; + size_t right = array_size - 1; + + while(left <= right) { + size_t mid = (left + right) >> 1; + if (array[mid] >= value) right = mid - 1; + else left = mid + 1; + } + if(left >= array_size || array[left] > value) left--; + return left; +} + +static void addLengthDistance(uivector* values, size_t length, size_t distance) { + /*values in encoded vector are those used by deflate: + 0-255: literal bytes + 256: end + 257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits) + 286-287: invalid*/ + + unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length); + unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]); + unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance); + unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]); + + 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); +} + +/*3 bytes of data get encoded into two bytes. The hash cannot use more than 3 +bytes as input because 3 is the minimum match length for deflate*/ +static const unsigned HASH_NUM_VALUES = 65536; +static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/ + +typedef struct Hash { + int* head; /*hash value to head circular pos - can be outdated if went around window*/ + /*circular pos to prev circular pos*/ + unsigned short* chain; + int* val; /*circular pos to hash value*/ + + /*TODO: do this not only for zeros but for any repeated byte. However for PNG + it's always going to be the zeros that dominate, so not important for PNG*/ + int* headz; /*similar to head, but for chainz*/ + unsigned short* chainz; /*those with same amount of zeros*/ + unsigned short* zeros; /*length of zeros streak, used as a second hash chain*/ +} Hash; + +static unsigned hash_init(Hash* hash, unsigned windowsize) { + unsigned i; + hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES); + hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize); + hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); + + hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); + hash->headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1)); + hash->chainz = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); + + if(!hash->head || !hash->chain || !hash->val || !hash->headz|| !hash->chainz || !hash->zeros) { + return 83; /*alloc fail*/ + } + + /*initialize hash table*/ + for(i = 0; i != HASH_NUM_VALUES; ++i) hash->head[i] = -1; + for(i = 0; i != windowsize; ++i) hash->val[i] = -1; + for(i = 0; i != windowsize; ++i) hash->chain[i] = i; /*same value as index indicates uninitialized*/ + + for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash->headz[i] = -1; + for(i = 0; i != windowsize; ++i) hash->chainz[i] = i; /*same value as index indicates uninitialized*/ + + return 0; +} + +static void hash_cleanup(Hash* hash) { + lodepng_free(hash->head); + lodepng_free(hash->val); + lodepng_free(hash->chain); + + lodepng_free(hash->zeros); + lodepng_free(hash->headz); + lodepng_free(hash->chainz); +} + + + +static unsigned getHash(const unsigned char* data, size_t size, size_t pos) { + unsigned result = 0; + if(pos + 2 < size) { + /*A simple shift and xor hash is used. Since the data of PNGs is dominated + by zeroes due to the filters, a better hash does not have a significant + effect on speed in traversing the chain, and causes more time spend on + calculating the hash.*/ + result ^= (unsigned)(data[pos + 0] << 0u); + result ^= (unsigned)(data[pos + 1] << 4u); + result ^= (unsigned)(data[pos + 2] << 8u); + } else { + size_t amount, i; + if(pos >= size) return 0; + amount = size - pos; + for(i = 0; i != amount; ++i) result ^= (unsigned)(data[pos + i] << (i * 8u)); + } + return result & HASH_BIT_MASK; +} + +static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) { + const unsigned char* start = data + pos; + const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH; + if(end > data + size) end = data + size; + data = start; + while(data != end && *data == 0) ++data; + /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/ + return (unsigned)(data - start); +} + +/*wpos = pos & (windowsize - 1)*/ +static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros) { + hash->val[wpos] = (int)hashval; + if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval]; + hash->head[hashval] = (int)wpos; + + hash->zeros[wpos] = numzeros; + if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros]; + hash->headz[numzeros] = (int)wpos; +} + +/* +LZ77-encode the data. Return value is error code. The input are raw bytes, the output +is in the form of unsigned integers with codes representing for example literal bytes, or +length/distance pairs. +It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a +sliding window (of windowsize) is used, and all past bytes in that window can be used as +the "dictionary". A brute force search through all possible distances would be slow, and +this hash technique is one out of several ways to speed this up. +*/ +static unsigned encodeLZ77(uivector* out, Hash* hash, + const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize, + unsigned minmatch, unsigned nicematch, unsigned lazymatching) { + size_t pos; + unsigned i, error = 0; + /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/ + unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8; + unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64; + + unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/ + unsigned numzeros = 0; + + unsigned offset; /*the offset represents the distance in LZ77 terminology*/ + unsigned length; + unsigned lazy = 0; + unsigned lazylength = 0, lazyoffset = 0; + unsigned hashval; + unsigned current_offset, current_length; + unsigned prev_offset; + const unsigned char *lastptr, *foreptr, *backptr; + unsigned hashpos; + + if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/ + if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/ + + if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH; + + for(pos = inpos; pos < insize; ++pos) { + size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/ + unsigned chainlength = 0; + + hashval = getHash(in, insize, pos); + + if(usezeros && hashval == 0) { + if(numzeros == 0) numzeros = countZeros(in, insize, pos); + else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; + } else { + numzeros = 0; + } + + updateHashChain(hash, wpos, hashval, numzeros); + + /*the length and offset found for the current position*/ + length = 0; + offset = 0; + + hashpos = hash->chain[wpos]; + + lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH]; + + /*search for the longest string*/ + prev_offset = 0; + for(;;) { + if(chainlength++ >= maxchainlength) break; + current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize); + + if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/ + prev_offset = current_offset; + if(current_offset > 0) { + /*test the next characters*/ + foreptr = &in[pos]; + backptr = &in[pos - current_offset]; + + /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/ + if(numzeros >= 3) { + unsigned skip = hash->zeros[hashpos]; + if(skip > numzeros) skip = numzeros; + backptr += skip; + foreptr += skip; + } + + while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ { + ++backptr; + ++foreptr; + } + current_length = (unsigned)(foreptr - &in[pos]); + + if(current_length > length) { + length = current_length; /*the longest length*/ + offset = current_offset; /*the offset that is related to this longest length*/ + /*jump out once a length of max length is found (speed gain). This also jumps + out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/ + if(current_length >= nicematch) break; + } + } + + if(hashpos == hash->chain[hashpos]) break; + + if(numzeros >= 3 && length > numzeros) { + hashpos = hash->chainz[hashpos]; + if(hash->zeros[hashpos] != numzeros) break; + } else { + hashpos = hash->chain[hashpos]; + /*outdated hash value, happens if particular value was not encountered in whole last window*/ + if(hash->val[hashpos] != (int)hashval) break; + } + } + + if(lazymatching) { + if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) { + lazy = 1; + lazylength = length; + lazyoffset = offset; + continue; /*try the next byte*/ + } + if(lazy) { + lazy = 0; + if(pos == 0) ERROR_BREAK(81); + if(length > lazylength + 1) { + /*push the previous character as literal*/ + if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/); + } else { + length = lazylength; + offset = lazyoffset; + hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/ + hash->headz[numzeros] = -1; /*idem*/ + --pos; + } + } + } + if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/); + + /*encode it as length/distance pair or literal value*/ + if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ { + if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); + } else if(length < minmatch || (length == 3 && offset > 4096)) { + /*compensate for the fact that longer offsets have more extra bits, a + length of only 3 may be not worth it then*/ + if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); + } else { + addLengthDistance(out, length, offset); + for(i = 1; i < length; ++i) { + ++pos; + wpos = pos & (windowsize - 1); + hashval = getHash(in, insize, pos); + if(usezeros && hashval == 0) { + if(numzeros == 0) numzeros = countZeros(in, insize, pos); + else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; + } else { + numzeros = 0; + } + updateHashChain(hash, wpos, hashval, numzeros); + } + } + } /*end of the loop through each character of input*/ + + return error; +} + +/* /////////////////////////////////////////////////////////////////////////// */ + +static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) { + /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte, + 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/ + + size_t i, 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 & 255)); + ucvector_push_back(out, (unsigned char)(LEN >> 8)); + ucvector_push_back(out, (unsigned char)(NLEN & 255)); + ucvector_push_back(out, (unsigned char)(NLEN >> 8)); + + /*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, unsigned final) { + unsigned error = 0; + + /* + A block is compressed as follows: The PNG data is lz77 encoded, resulting in + literal bytes and length/distance pairs. This is then huffman compressed with + two huffman trees. One huffman tree is used for the lit and len values ("ll"), + another huffman tree is used for the dist values ("d"). These two trees are + stored using their code lengths, and to compress even more these code lengths + are also run-length encoded and huffman compressed. This gives a huffman tree + of code lengths "cl". The code 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 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, + settings->minmatch, settings->nicematch, settings->lazymatching); + if(error) break; + } else { + if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/); + for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/ + } + + 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, 257, frequencies_ll.size, 15); + if(error) break; + /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/ + error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d.data, 2, 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, frequencies_cl.size, 7); + if(error) break; + + if(!uivector_resize(&bitlen_cl, tree_cl.numcodes)) ERROR_BREAK(83 /*alloc fail*/); + for(i = 0; i != tree_cl.numcodes; ++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; + /*trim zeroes for HCLEN. HLIT and HDIST were already trimmed at tree creation*/ + while(!bitlen_cl.data[HCLEN + 4 - 1] && HCLEN > 0) --HCLEN; + 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, unsigned final) { + HuffmanTree tree_ll; /*tree for literal values and length codes*/ + HuffmanTree tree_d; /*tree for distance codes*/ + + unsigned BFINAL = final; + unsigned error = 0; + size_t i; + + HuffmanTree_init(&tree_ll); + HuffmanTree_init(&tree_d); + + 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, + settings->minmatch, settings->nicematch, settings->lazymatching); + 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) { + unsigned error = 0; + size_t i, blocksize, numdeflateblocks; + size_t bp = 0; /*the bit pointer*/ + Hash hash; + + if(settings->btype > 2) return 61; + else if(settings->btype == 0) return deflateNoCompression(out, in, insize); + else if(settings->btype == 1) blocksize = insize; + else /*if(settings->btype == 2)*/ { + /*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/ + blocksize = insize / 8 + 8; + if(blocksize < 65536) blocksize = 65536; + if(blocksize > 262144) blocksize = 262144; + } + + numdeflateblocks = (insize + blocksize - 1) / blocksize; + if(numdeflateblocks == 0) numdeflateblocks = 1; + + error = hash_init(&hash, settings->windowsize); + if(error) return error; + + for(i = 0; i != numdeflateblocks && !error; ++i) { + unsigned final = (i == numdeflateblocks - 1); + size_t start = i * blocksize; + size_t end = start + blocksize; + if(end > insize) end = insize; + + if(settings->btype == 1) error = deflateFixed(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; +} + +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; +} + +static unsigned deflate(unsigned char** out, size_t* outsize, + const unsigned char* in, size_t insize, + const LodePNGCompressSettings* settings) { + if(settings->custom_deflate) { + return settings->custom_deflate(out, outsize, in, insize, settings); + } else { + return lodepng_deflate(out, outsize, in, insize, settings); + } +} + +#endif /*LODEPNG_COMPILE_DECODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Adler32 */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) { + unsigned s1 = adler & 0xffff; + unsigned s2 = (adler >> 16) & 0xffff; + + while(len > 0) { + /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/ + unsigned amount = len > 5552 ? 5552 : len; + len -= amount; + while(amount > 0) { + s1 += (*data++); + 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) { + 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 = 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*/ +} + +static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGDecompressSettings* settings) { + if(settings->custom_zlib) { + return settings->custom_zlib(out, outsize, in, insize, settings); + } else { + return lodepng_zlib_decompress(out, outsize, in, insize, settings); + } +} + +#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) { + /*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 outv; + size_t i; + unsigned error; + unsigned char* deflatedata = 0; + size_t deflatesize = 0; + + /*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 >> 8)); + ucvector_push_back(&outv, (unsigned char)(CMFFLG & 255)); + + error = deflate(&deflatedata, &deflatesize, in, insize, settings); + + if(!error) { + unsigned ADLER32 = adler32(in, (unsigned)insize); + for(i = 0; i != deflatesize; ++i) ucvector_push_back(&outv, deflatedata[i]); + lodepng_free(deflatedata); + lodepng_add32bitInt(&outv, ADLER32); + } + + *out = outv.data; + *outsize = outv.size; + + return error; +} + +/* compress using the default or custom zlib function */ +static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGCompressSettings* settings) { + if(settings->custom_zlib) { + return settings->custom_zlib(out, outsize, in, insize, settings); + } else { + return lodepng_zlib_compress(out, outsize, in, insize, settings); + } +} + +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#else /*no LODEPNG_COMPILE_ZLIB*/ + +#ifdef LODEPNG_COMPILE_DECODER +static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGDecompressSettings* settings) { + if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ + return settings->custom_zlib(out, outsize, in, insize, settings); +} +#endif /*LODEPNG_COMPILE_DECODER*/ +#ifdef LODEPNG_COMPILE_ENCODER +static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, + size_t insize, const LodePNGCompressSettings* settings) { + if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ + return settings->custom_zlib(out, outsize, in, insize, settings); +} +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#endif /*LODEPNG_COMPILE_ZLIB*/ + +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_ENCODER + +/*this is a good tradeoff between speed and compression ratio*/ +#define DEFAULT_WINDOWSIZE 2048 + +void lodepng_compress_settings_init(LodePNGCompressSettings* settings) { + /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/ + settings->btype = 2; + settings->use_lz77 = 1; + settings->windowsize = DEFAULT_WINDOWSIZE; + settings->minmatch = 3; + settings->nicematch = 128; + settings->lazymatching = 1; + + settings->custom_zlib = 0; + settings->custom_deflate = 0; + settings->custom_context = 0; +} + +const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0}; + + +#endif /*LODEPNG_COMPILE_ENCODER*/ + +#ifdef LODEPNG_COMPILE_DECODER + +void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) { + settings->ignore_adler32 = 0; + + settings->custom_zlib = 0; + settings->custom_inflate = 0; + settings->custom_context = 0; +} + +const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0}; + +#endif /*LODEPNG_COMPILE_DECODER*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // End of Zlib related code. Begin of PNG related code. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_PNG + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / CRC32 / */ +/* ////////////////////////////////////////////////////////////////////////// */ + + +#ifndef LODEPNG_NO_COMPILE_CRC +/* CRC polynomial: 0xedb88320 */ +static unsigned lodepng_crc32_table[256] = { + 0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u, 3915621685u, 2657392035u, + 249268274u, 2044508324u, 3772115230u, 2547177864u, 162941995u, 2125561021u, 3887607047u, 2428444049u, + 498536548u, 1789927666u, 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u, + 325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u, 4195302755u, 2366115317u, + 997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u, + 901097722u, 1119000684u, 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u, + 651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u, 3485111705u, 3099436303u, + 671266974u, 1594198024u, 3322730930u, 2970347812u, 795835527u, 1483230225u, 3244367275u, 3060149565u, + 1994146192u, 31158534u, 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u, + 2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u, 2439277719u, 3865271297u, + 1802195444u, 476864866u, 2238001368u, 4066508878u, 1812370925u, 453092731u, 2181625025u, 4111451223u, + 1706088902u, 314042704u, 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u, + 1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u, + 1131014506u, 879679996u, 2909243462u, 3663771856u, 1141124467u, 855842277u, 2852801631u, 3708648649u, + 1342533948u, 654459306u, 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u, + 1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u, 3082640443u, 3233442989u, + 3988292384u, 2596254646u, 62317068u, 1957810842u, 3939845945u, 2647816111u, 81470997u, 1943803523u, + 3814918930u, 2489596804u, 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u, + 4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u, 426522225u, 1852507879u, + 4275313526u, 2312317920u, 282753626u, 1742555852u, 4189708143u, 2394877945u, 397917763u, 1622183637u, + 3604390888u, 2714866558u, 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u, + 3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u, 829329135u, 1181335161u, + 3412177804u, 3160834842u, 628085408u, 1382605366u, 3423369109u, 3138078467u, 570562233u, 1426400815u, + 3317316542u, 2998733608u, 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u, + 2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u, 1913087877u, 83908371u, + 2512341634u, 3803740692u, 2075208622u, 213261112u, 2463272603u, 3855990285u, 2094854071u, 198958881u, + 2262029012u, 4057260610u, 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u, + 2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u, 1634467795u, 376229701u, + 2685067896u, 3608007406u, 1308918612u, 956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u, + 2932959818u, 3654703836u, 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u, + 3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u, 1423857449u, 601450431u, + 3009837614u, 3294710456u, 1567103746u, 711928724u, 3020668471u, 3272380065u, 1510334235u, 755167117u +}; + +/*Return the CRC of the bytes buf[0..len-1].*/ +unsigned lodepng_crc32(const unsigned char* data, size_t length) { + unsigned r = 0xffffffffu; + size_t i; + for(i = 0; i < length; ++i) { + r = lodepng_crc32_table[(r ^ data[i]) & 0xff] ^ (r >> 8); + } + return r ^ 0xffffffffu; +} +#else /* !LODEPNG_NO_COMPILE_CRC */ +unsigned lodepng_crc32(const unsigned char* data, size_t length); +#endif /* !LODEPNG_NO_COMPILE_CRC */ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / 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 = 0 ; i < nbits; ++i) { + result <<= 1; + result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream); + } + 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] = (char)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) { + if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 + && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { + /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ + return chunk + 8; + } else { + 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) { + if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 + && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { + /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ + return chunk + 8; + } else { + unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12; + return chunk + total_chunk_length; + } +} + +unsigned char* lodepng_chunk_find(unsigned char* chunk, const unsigned char* end, const char type[5]) { + for(;;) { + if(chunk + 12 >= end) return 0; + if(lodepng_chunk_type_equals(chunk, type)) return chunk; + chunk = lodepng_chunk_next(chunk); + } +} + +const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]) { + for(;;) { + if(chunk + 12 >= end) return 0; + if(lodepng_chunk_type_equals(chunk, type)) return chunk; + chunk = lodepng_chunk_next_const(chunk); + } +} + +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*)lodepng_realloc(*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*)lodepng_realloc(*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] = (unsigned char)type[0]; + chunk[5] = (unsigned char)type[1]; + chunk[6] = (unsigned char)type[2]; + chunk[7] = (unsigned char)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; /*gray*/ + 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; /*gray + 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; /*gray*/ + case 2: return 3; /*RGB*/ + case 3: return 1; /*palette*/ + case 4: return 2; /*gray + 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*)lodepng_malloc(1024); + 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; +} + +LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) { + LodePNGColorMode result; + lodepng_color_mode_init(&result); + result.colortype = colortype; + result.bitdepth = bitdepth; + return result; +} + +static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) { + size_t i; + if(a->colortype != b->colortype) return 0; + if(a->bitdepth != b->bitdepth) return 0; + if(a->key_defined != b->key_defined) return 0; + if(a->key_defined) { + if(a->key_r != b->key_r) return 0; + if(a->key_g != b->key_g) return 0; + if(a->key_b != b->key_b) return 0; + } + if(a->palettesize != b->palettesize) return 0; + for(i = 0; i != a->palettesize * 4; ++i) { + if(a->palette[i] != b->palette[i]) return 0; + } + return 1; +} + +void lodepng_palette_clear(LodePNGColorMode* info) { + if(info->palette) lodepng_free(info->palette); + info->palette = 0; + info->palettesize = 0; +} + +unsigned lodepng_palette_add(LodePNGColorMode* info, + unsigned char r, unsigned char g, unsigned char b, unsigned char a) { + 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->palette) /*allocate palette if empty*/ { + /*room for 256 colors with 4 bytes each*/ + data = (unsigned char*)lodepng_realloc(info->palette, 1024); + 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; +} + +/*calculate bits per pixel out of colortype and bitdepth*/ +unsigned lodepng_get_bpp(const LodePNGColorMode* info) { + return lodepng_get_bpp_lct(info->colortype, info->bitdepth); +} + +unsigned lodepng_get_channels(const LodePNGColorMode* info) { + return getNumColorChannels(info->colortype); +} + +unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info) { + return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA; +} + +unsigned lodepng_is_alpha_type(const LodePNGColorMode* info) { + return (info->colortype & 4) != 0; /*4 or 6*/ +} + +unsigned lodepng_is_palette_type(const LodePNGColorMode* info) { + return info->colortype == LCT_PALETTE; +} + +unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info) { + size_t i; + for(i = 0; i != info->palettesize; ++i) { + if(info->palette[i * 4 + 3] < 255) return 1; + } + return 0; +} + +unsigned lodepng_can_have_alpha(const LodePNGColorMode* info) { + return info->key_defined + || lodepng_is_alpha_type(info) + || lodepng_has_palette_alpha(info); +} + +size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { + size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth); + size_t n = (size_t)w * (size_t)h; + return ((n / 8) * bpp) + ((n & 7) * bpp + 7) / 8; +} + +size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) { + return lodepng_get_raw_size_lct(w, h, color->colortype, color->bitdepth); +} + + +#ifdef LODEPNG_COMPILE_PNG +#ifdef LODEPNG_COMPILE_DECODER + +/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer, +and in addition has one extra byte per line: the filter byte. So this gives a larger +result than lodepng_get_raw_size. */ +static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, const LodePNGColorMode* color) { + size_t bpp = lodepng_get_bpp(color); + /* + 1 for the filter byte, and possibly plus padding bits per line */ + size_t line = ((size_t)(w / 8) * bpp) + 1 + ((w & 7) * bpp + 7) / 8; + return (size_t)h * line; +} + +/* Safely check if multiplying two integers will overflow (no undefined +behavior, compiler removing the code, etc...) and output result. */ +static int lodepng_mulofl(size_t a, size_t b, size_t* result) { + *result = a * b; /* Unsigned multiplication is well defined and safe in C90 */ + return (a != 0 && *result / a != b); +} + +/* Safely check if adding two integers will overflow (no undefined +behavior, compiler removing the code, etc...) and output result. */ +static int lodepng_addofl(size_t a, size_t b, size_t* result) { + *result = a + b; /* Unsigned addition is well defined and safe in C90 */ + return *result < a; +} + +/*Safely checks whether size_t overflow can be caused due to amount of pixels. +This check is overcautious rather than precise. If this check indicates no overflow, +you can safely compute in a size_t (but not an unsigned): +-(size_t)w * (size_t)h * 8 +-amount of bytes in IDAT (including filter, padding and Adam7 bytes) +-amount of bytes in raw color model +Returns 1 if overflow possible, 0 if not. +*/ +static int lodepng_pixel_overflow(unsigned w, unsigned h, + const LodePNGColorMode* pngcolor, const LodePNGColorMode* rawcolor) { + size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor)); + size_t numpixels, total; + size_t line; /* bytes per line in worst case */ + + if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1; + if(lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */ + + /* Bytes per scanline with the expression "(w / 8) * bpp) + ((w & 7) * bpp + 7) / 8" */ + if(lodepng_mulofl((size_t)(w / 8), bpp, &line)) return 1; + if(lodepng_addofl(line, ((w & 7) * bpp + 7) / 8, &line)) return 1; + + if(lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */ + if(lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */ + + return 0; /* no overflow */ +} +#endif /*LODEPNG_COMPILE_DECODER*/ +#endif /*LODEPNG_COMPILE_PNG*/ + +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + +static void LodePNGUnknownChunks_init(LodePNGInfo* info) { + unsigned i; + for(i = 0; i != 3; ++i) info->unknown_chunks_data[i] = 0; + for(i = 0; i != 3; ++i) info->unknown_chunks_size[i] = 0; +} + +static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) { + unsigned i; + for(i = 0; i != 3; ++i) lodepng_free(info->unknown_chunks_data[i]); +} + +static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) { + unsigned i; + + LodePNGUnknownChunks_cleanup(dest); + + for(i = 0; i != 3; ++i) { + size_t j; + dest->unknown_chunks_size[i] = src->unknown_chunks_size[i]; + dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]); + if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/ + for(j = 0; j < src->unknown_chunks_size[i]; ++j) { + dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j]; + } + } + + return 0; +} + +/******************************************************************************/ + +static void LodePNGText_init(LodePNGInfo* info) { + info->text_num = 0; + info->text_keys = NULL; + info->text_strings = NULL; +} + +static void LodePNGText_cleanup(LodePNGInfo* info) { + size_t i; + for(i = 0; i != info->text_num; ++i) { + string_cleanup(&info->text_keys[i]); + string_cleanup(&info->text_strings[i]); + } + lodepng_free(info->text_keys); + lodepng_free(info->text_strings); +} + +static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { + size_t i = 0; + dest->text_keys = 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**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1))); + char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1))); + if(!new_keys || !new_strings) { + lodepng_free(new_keys); + lodepng_free(new_strings); + return 83; /*alloc fail*/ + } + + ++info->text_num; + info->text_keys = new_keys; + info->text_strings = new_strings; + + info->text_keys[info->text_num - 1] = alloc_string(key); + info->text_strings[info->text_num - 1] = alloc_string(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]); + } + lodepng_free(info->itext_keys); + lodepng_free(info->itext_langtags); + lodepng_free(info->itext_transkeys); + lodepng_free(info->itext_strings); +} + +static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { + size_t i = 0; + dest->itext_keys = 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**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1))); + char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1))); + char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1))); + char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1))); + if(!new_keys || !new_langtags || !new_transkeys || !new_strings) { + lodepng_free(new_keys); + lodepng_free(new_langtags); + lodepng_free(new_transkeys); + lodepng_free(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; + + info->itext_keys[info->itext_num - 1] = alloc_string(key); + info->itext_langtags[info->itext_num - 1] = alloc_string(langtag); + info->itext_transkeys[info->itext_num - 1] = alloc_string(transkey); + info->itext_strings[info->itext_num - 1] = alloc_string(str); + + return 0; +} + +/* same as set but does not delete */ +static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) { + info->iccp_name = alloc_string(name); + info->iccp_profile = (unsigned char*)lodepng_malloc(profile_size); + + if(!info->iccp_name || !info->iccp_profile) return 83; /*alloc fail*/ + + memcpy(info->iccp_profile, profile, profile_size); + info->iccp_profile_size = profile_size; + + return 0; /*ok*/ +} + +unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) { + if(info->iccp_name) lodepng_clear_icc(info); + info->iccp_defined = 1; + + return lodepng_assign_icc(info, name, profile, profile_size); +} + +void lodepng_clear_icc(LodePNGInfo* info) { + string_cleanup(&info->iccp_name); + lodepng_free(info->iccp_profile); + info->iccp_profile = NULL; + info->iccp_profile_size = 0; + info->iccp_defined = 0; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + +void lodepng_info_init(LodePNGInfo* info) { + lodepng_color_mode_init(&info->color); + info->interlace_method = 0; + info->compression_method = 0; + info->filter_method = 0; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + info->background_defined = 0; + info->background_r = info->background_g = info->background_b = 0; + + LodePNGText_init(info); + LodePNGIText_init(info); + + info->time_defined = 0; + info->phys_defined = 0; + + info->gama_defined = 0; + info->chrm_defined = 0; + info->srgb_defined = 0; + info->iccp_defined = 0; + info->iccp_name = NULL; + info->iccp_profile = NULL; + + LodePNGUnknownChunks_init(info); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +} + +void lodepng_info_cleanup(LodePNGInfo* info) { + lodepng_color_mode_cleanup(&info->color); +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + LodePNGText_cleanup(info); + LodePNGIText_cleanup(info); + + lodepng_clear_icc(info); + + LodePNGUnknownChunks_cleanup(info); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +} + +unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) { + lodepng_info_cleanup(dest); + *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)); + if(source->iccp_defined) { + CERROR_TRY_RETURN(lodepng_assign_icc(dest, source->iccp_name, source->iccp_profile, source->iccp_profile_size)); + } + + LodePNGUnknownChunks_init(dest); + CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source)); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + return 0; +} + +/* ////////////////////////////////////////////////////////////////////////// */ + +/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/ +static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) { + unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/ + /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/ + unsigned p = index & m; + in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/ + in = in << (bits * (m - p)); + if(p == 0) out[index * bits / 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 like an octree, but because the alpha channel is used too, each +node has 16 instead of 8 children. +*/ +struct ColorTree { + ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/ + int index; /*the payload. Only has a meaningful value if this is in the last level*/ +}; + +static void color_tree_init(ColorTree* tree) { + int i; + for(i = 0; i != 16; ++i) tree->children[i] = 0; + tree->index = -1; +} + +static void color_tree_cleanup(ColorTree* tree) { + int i; + for(i = 0; i != 16; ++i) { + if(tree->children[i]) { + color_tree_cleanup(tree->children[i]); + lodepng_free(tree->children[i]); + } + } +} + +/*returns -1 if color not present, its index otherwise*/ +static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { + int bit = 0; + for(bit = 0; bit < 8; ++bit) { + int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); + if(!tree->children[i]) return -1; + else tree = tree->children[i]; + } + return tree ? tree->index : -1; +} + +#ifdef LODEPNG_COMPILE_ENCODER +static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { + return color_tree_get(tree, r, g, b, a) >= 0; +} +#endif /*LODEPNG_COMPILE_ENCODER*/ + +/*color is not allowed to already exist. +Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist")*/ +static void color_tree_add(ColorTree* tree, + unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) { + int bit; + for(bit = 0; bit < 8; ++bit) { + int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); + if(!tree->children[i]) { + tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree)); + color_tree_init(tree->children[i]); + } + tree = tree->children[i]; + } + tree->index = (int)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 gray = r; /*((unsigned short)r + g + b) / 3;*/ + if(mode->bitdepth == 8) out[i] = gray; + else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray; + else { + /*take the most significant bits of gray*/ + gray = (gray >> (8 - mode->bitdepth)) & ((1 << mode->bitdepth) - 1); + addColorBits(out, i, mode->bitdepth, gray); + } + } else if(mode->colortype == LCT_RGB) { + if(mode->bitdepth == 8) { + out[i * 3 + 0] = r; + out[i * 3 + 1] = g; + out[i * 3 + 2] = b; + } else { + out[i * 6 + 0] = out[i * 6 + 1] = r; + out[i * 6 + 2] = out[i * 6 + 3] = g; + out[i * 6 + 4] = out[i * 6 + 5] = b; + } + } else if(mode->colortype == LCT_PALETTE) { + int index = color_tree_get(tree, r, g, b, a); + if(index < 0) return 82; /*color not in palette*/ + if(mode->bitdepth == 8) out[i] = index; + else addColorBits(out, i, mode->bitdepth, (unsigned)index); + } else if(mode->colortype == LCT_GREY_ALPHA) { + unsigned char gray = r; /*((unsigned short)r + g + b) / 3;*/ + if(mode->bitdepth == 8) { + out[i * 2 + 0] = gray; + out[i * 2 + 1] = a; + } else if(mode->bitdepth == 16) { + out[i * 4 + 0] = out[i * 4 + 1] = gray; + out[i * 4 + 2] = out[i * 4 + 3] = a; + } + } else if(mode->colortype == LCT_RGBA) { + if(mode->bitdepth == 8) { + out[i * 4 + 0] = r; + out[i * 4 + 1] = g; + out[i * 4 + 2] = b; + out[i * 4 + 3] = a; + } else { + out[i * 8 + 0] = out[i * 8 + 1] = r; + out[i * 8 + 2] = out[i * 8 + 3] = g; + out[i * 8 + 4] = out[i * 8 + 5] = b; + out[i * 8 + 6] = out[i * 8 + 7] = a; + } + } + + return 0; /*no error*/ +} + +/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/ +static void rgba16ToPixel(unsigned char* out, size_t i, + const LodePNGColorMode* mode, + unsigned short r, unsigned short g, unsigned short b, unsigned short a) { + if(mode->colortype == LCT_GREY) { + unsigned short gray = r; /*((unsigned)r + g + b) / 3;*/ + out[i * 2 + 0] = (gray >> 8) & 255; + out[i * 2 + 1] = gray & 255; + } else if(mode->colortype == LCT_RGB) { + out[i * 6 + 0] = (r >> 8) & 255; + out[i * 6 + 1] = r & 255; + out[i * 6 + 2] = (g >> 8) & 255; + out[i * 6 + 3] = g & 255; + out[i * 6 + 4] = (b >> 8) & 255; + out[i * 6 + 5] = b & 255; + } else if(mode->colortype == LCT_GREY_ALPHA) { + unsigned short gray = r; /*((unsigned)r + g + b) / 3;*/ + out[i * 4 + 0] = (gray >> 8) & 255; + out[i * 4 + 1] = gray & 255; + out[i * 4 + 2] = (a >> 8) & 255; + out[i * 4 + 3] = a & 255; + } else if(mode->colortype == LCT_RGBA) { + out[i * 8 + 0] = (r >> 8) & 255; + out[i * 8 + 1] = r & 255; + out[i * 8 + 2] = (g >> 8) & 255; + out[i * 8 + 3] = g & 255; + out[i * 8 + 4] = (b >> 8) & 255; + out[i * 8 + 5] = b & 255; + out[i * 8 + 6] = (a >> 8) & 255; + out[i * 8 + 7] = a & 255; + } +} + +/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/ +static void getPixelColorRGBA8(unsigned char* r, unsigned char* g, + unsigned char* b, unsigned char* a, + const unsigned char* in, size_t i, + const LodePNGColorMode* mode) { + if(mode->colortype == LCT_GREY) { + if(mode->bitdepth == 8) { + *r = *g = *b = in[i]; + if(mode->key_defined && *r == mode->key_r) *a = 0; + else *a = 255; + } else if(mode->bitdepth == 16) { + *r = *g = *b = in[i * 2 + 0]; + if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; + else *a = 255; + } else { + unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ + size_t j = i * mode->bitdepth; + unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); + *r = *g = *b = (value * 255) / highest; + if(mode->key_defined && value == mode->key_r) *a = 0; + else *a = 255; + } + } else if(mode->colortype == LCT_RGB) { + if(mode->bitdepth == 8) { + *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2]; + if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0; + else *a = 255; + } else { + *r = in[i * 6 + 0]; + *g = in[i * 6 + 2]; + *b = in[i * 6 + 4]; + if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; + else *a = 255; + } + } else if(mode->colortype == LCT_PALETTE) { + unsigned index; + if(mode->bitdepth == 8) index = in[i]; + else { + size_t j = i * mode->bitdepth; + index = readBitsFromReversedStream(&j, in, mode->bitdepth); + } + + if(index >= mode->palettesize) { + /*This is an error according to the PNG spec, but common PNG decoders make it black instead. + Done here too, slightly faster due to no error handling needed.*/ + *r = *g = *b = 0; + *a = 255; + } else { + *r = mode->palette[index * 4 + 0]; + *g = mode->palette[index * 4 + 1]; + *b = mode->palette[index * 4 + 2]; + *a = mode->palette[index * 4 + 3]; + } + } else if(mode->colortype == LCT_GREY_ALPHA) { + if(mode->bitdepth == 8) { + *r = *g = *b = in[i * 2 + 0]; + *a = in[i * 2 + 1]; + } else { + *r = *g = *b = in[i * 4 + 0]; + *a = in[i * 4 + 2]; + } + } else if(mode->colortype == LCT_RGBA) { + if(mode->bitdepth == 8) { + *r = in[i * 4 + 0]; + *g = in[i * 4 + 1]; + *b = in[i * 4 + 2]; + *a = in[i * 4 + 3]; + } else { + *r = in[i * 8 + 0]; + *g = in[i * 8 + 2]; + *b = in[i * 8 + 4]; + *a = in[i * 8 + 6]; + } + } +} + +/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color +mode test cases, optimized to convert the colors much faster, when converting +to RGBA or RGB with 8 bit per cannel. buffer must be RGBA or RGB output with +enough memory, if has_alpha is true the output is RGBA. mode has the color mode +of the input buffer.*/ +static void getPixelColorsRGBA8(unsigned char* buffer, size_t numpixels, + unsigned has_alpha, const unsigned char* in, + const LodePNGColorMode* mode) { + unsigned num_channels = has_alpha ? 4 : 3; + size_t i; + if(mode->colortype == LCT_GREY) { + if(mode->bitdepth == 8) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i]; + if(has_alpha) buffer[3] = mode->key_defined && in[i] == mode->key_r ? 0 : 255; + } + } else if(mode->bitdepth == 16) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2]; + if(has_alpha) buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255; + } + } else { + unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ + size_t j = 0; + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); + buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; + if(has_alpha) buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255; + } + } + } else if(mode->colortype == LCT_RGB) { + if(mode->bitdepth == 8) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 3 + 0]; + buffer[1] = in[i * 3 + 1]; + buffer[2] = in[i * 3 + 2]; + if(has_alpha) buffer[3] = mode->key_defined && buffer[0] == mode->key_r + && buffer[1]== mode->key_g && buffer[2] == mode->key_b ? 0 : 255; + } + } else { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 6 + 0]; + buffer[1] = in[i * 6 + 2]; + buffer[2] = in[i * 6 + 4]; + if(has_alpha) buffer[3] = mode->key_defined + && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255; + } + } + } else if(mode->colortype == LCT_PALETTE) { + unsigned index; + size_t j = 0; + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + if(mode->bitdepth == 8) index = in[i]; + else index = readBitsFromReversedStream(&j, in, mode->bitdepth); + + if(index >= mode->palettesize) { + /*This is an error according to the PNG spec, but most PNG decoders make it black instead. + Done here too, slightly faster due to no error handling needed.*/ + buffer[0] = buffer[1] = buffer[2] = 0; + if(has_alpha) buffer[3] = 255; + } else { + buffer[0] = mode->palette[index * 4 + 0]; + buffer[1] = mode->palette[index * 4 + 1]; + buffer[2] = mode->palette[index * 4 + 2]; + if(has_alpha) buffer[3] = mode->palette[index * 4 + 3]; + } + } + } else if(mode->colortype == LCT_GREY_ALPHA) { + if(mode->bitdepth == 8) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; + if(has_alpha) buffer[3] = in[i * 2 + 1]; + } + } else { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; + if(has_alpha) buffer[3] = in[i * 4 + 2]; + } + } + } else if(mode->colortype == LCT_RGBA) { + if(mode->bitdepth == 8) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 4 + 0]; + buffer[1] = in[i * 4 + 1]; + buffer[2] = in[i * 4 + 2]; + if(has_alpha) buffer[3] = in[i * 4 + 3]; + } + } else { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 8 + 0]; + buffer[1] = in[i * 8 + 2]; + buffer[2] = in[i * 8 + 4]; + if(has_alpha) buffer[3] = in[i * 8 + 6]; + } + } + } +} + +/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with +given color type, but the given color type must be 16-bit itself.*/ +static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a, + const unsigned char* in, size_t i, const LodePNGColorMode* mode) { + if(mode->colortype == LCT_GREY) { + *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1]; + if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; + else *a = 65535; + } else if(mode->colortype == LCT_RGB) { + *r = 256u * in[i * 6 + 0] + in[i * 6 + 1]; + *g = 256u * in[i * 6 + 2] + in[i * 6 + 3]; + *b = 256u * in[i * 6 + 4] + in[i * 6 + 5]; + if(mode->key_defined + && 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; + else *a = 65535; + } else if(mode->colortype == LCT_GREY_ALPHA) { + *r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1]; + *a = 256u * in[i * 4 + 2] + in[i * 4 + 3]; + } else if(mode->colortype == LCT_RGBA) { + *r = 256u * in[i * 8 + 0] + in[i * 8 + 1]; + *g = 256u * in[i * 8 + 2] + in[i * 8 + 3]; + *b = 256u * in[i * 8 + 4] + in[i * 8 + 5]; + *a = 256u * in[i * 8 + 6] + in[i * 8 + 7]; + } +} + +unsigned lodepng_convert(unsigned char* out, const unsigned char* in, + const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, + unsigned w, unsigned h) { + size_t i; + ColorTree tree; + size_t numpixels = (size_t)w * (size_t)h; + unsigned error = 0; + + if(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 0; + } + + if(mode_out->colortype == LCT_PALETTE) { + size_t palettesize = mode_out->palettesize; + const unsigned char* palette = mode_out->palette; + size_t palsize = (size_t)1u << mode_out->bitdepth; + /*if the user specified output palette but did not give the values, assume + they want the values of the input color type (assuming that one is palette). + Note that we never create a new palette ourselves.*/ + if(palettesize == 0) { + palettesize = mode_in->palettesize; + palette = mode_in->palette; + /*if the input was also palette with same bitdepth, then the color types are also + equal, so copy literally. This to preserve the exact indices that were in the PNG + even in case there are duplicate colors in the palette.*/ + if (mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) { + size_t numbytes = lodepng_get_raw_size(w, h, mode_in); + for(i = 0; i != numbytes; ++i) out[i] = in[i]; + return 0; + } + } + if(palettesize < palsize) palsize = palettesize; + color_tree_init(&tree); + for(i = 0; i != palsize; ++i) { + const unsigned char* p = &palette[i * 4]; + color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i); + } + } + + if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) { + for(i = 0; i != numpixels; ++i) { + unsigned short r = 0, g = 0, b = 0, a = 0; + getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + rgba16ToPixel(out, i, mode_out, r, g, b, a); + } + } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) { + getPixelColorsRGBA8(out, numpixels, 1, in, mode_in); + } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) { + getPixelColorsRGBA8(out, numpixels, 0, in, mode_in); + } else { + unsigned char r = 0, g = 0, b = 0, a = 0; + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); + error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a); + if (error) break; + } + } + + if(mode_out->colortype == LCT_PALETTE) { + color_tree_cleanup(&tree); + } + + return error; +} + + +/* Converts a single rgb color without alpha from one type to another, color bits truncated to +their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow +function, do not use to process all pixels of an image. Alpha channel not supported on purpose: +this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the +specification it looks like bKGD should ignore the alpha values of the palette since it can use +any palette index but doesn't have an alpha channel. Idem with ignoring color key. */ +unsigned lodepng_convert_rgb( + unsigned* r_out, unsigned* g_out, unsigned* b_out, + unsigned r_in, unsigned g_in, unsigned b_in, + const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in) { + unsigned r = 0, g = 0, b = 0; + unsigned mul = 65535 / ((1u << mode_in->bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/ + unsigned shift = 16 - mode_out->bitdepth; + + if(mode_in->colortype == LCT_GREY || mode_in->colortype == LCT_GREY_ALPHA) { + r = g = b = r_in * mul; + } else if(mode_in->colortype == LCT_RGB || mode_in->colortype == LCT_RGBA) { + r = r_in * mul; + g = g_in * mul; + b = b_in * mul; + } else if(mode_in->colortype == LCT_PALETTE) { + if(r_in >= mode_in->palettesize) return 82; + r = mode_in->palette[r_in * 4 + 0] * 257u; + g = mode_in->palette[r_in * 4 + 1] * 257u; + b = mode_in->palette[r_in * 4 + 2] * 257u; + } else { + return 31; + } + + /* now convert to output format */ + if(mode_out->colortype == LCT_GREY || mode_out->colortype == LCT_GREY_ALPHA) { + *r_out = r >> shift ; + } else if(mode_out->colortype == LCT_RGB || mode_out->colortype == LCT_RGBA) { + *r_out = r >> shift ; + *g_out = g >> shift ; + *b_out = b >> shift ; + } else if(mode_out->colortype == LCT_PALETTE) { + unsigned i; + /* a 16-bit color cannot be in the palette */ + if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82; + for(i = 0; i < mode_out->palettesize; i++) { + unsigned j = i * 4; + if((r >> 8) == mode_out->palette[j + 0] && (g >> 8) == mode_out->palette[j + 1] && + (b >> 8) == mode_out->palette[j + 2]) { + *r_out = i; + return 0; + } + } + return 82; + } else { + return 31; + } + + return 0; +} + +#ifdef LODEPNG_COMPILE_ENCODER + +void lodepng_color_profile_init(LodePNGColorProfile* profile) { + profile->colored = 0; + profile->key = 0; + profile->key_r = profile->key_g = profile->key_b = 0; + profile->alpha = 0; + profile->numcolors = 0; + profile->bits = 1; + profile->numpixels = 0; +} + +/*function used for debug purposes with C++*/ +/*void printColorProfile(LodePNGColorProfile* p) { + std::cout << "colored: " << (int)p->colored << ", "; + std::cout << "key: " << (int)p->key << ", "; + std::cout << "key_r: " << (int)p->key_r << ", "; + std::cout << "key_g: " << (int)p->key_g << ", "; + std::cout << "key_b: " << (int)p->key_b << ", "; + std::cout << "alpha: " << (int)p->alpha << ", "; + std::cout << "numcolors: " << (int)p->numcolors << ", "; + std::cout << "bits: " << (int)p->bits << std::endl; +}*/ + +/*Returns how many bits needed to represent given value (max 8 bit)*/ +static unsigned getValueRequiredBits(unsigned char value) { + if(value == 0 || value == 255) return 1; + /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/ + if(value % 17 == 0) return value % 85 == 0 ? 2 : 4; + return 8; +} + +/*profile must already have been inited. +It's ok to set some parameters of profile to done already.*/ +unsigned lodepng_get_color_profile(LodePNGColorProfile* profile, + const unsigned char* in, unsigned w, unsigned h, + const LodePNGColorMode* mode_in) { + unsigned error = 0; + size_t i; + ColorTree tree; + size_t numpixels = (size_t)w * (size_t)h; + + /* mark things as done already if it would be impossible to have a more expensive case */ + unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0; + unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1; + unsigned numcolors_done = 0; + unsigned bpp = lodepng_get_bpp(mode_in); + unsigned bits_done = (profile->bits == 1 && bpp == 1) ? 1 : 0; + unsigned sixteen = 0; /* whether the input image is 16 bit */ + unsigned maxnumcolors = 257; + if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, profile->numcolors + (1u << bpp)); + + profile->numpixels += numpixels; + + color_tree_init(&tree); + + /*If the profile was already filled in from previous data, fill its palette in tree + and mark things as done already if we know they are the most expensive case already*/ + if(profile->alpha) alpha_done = 1; + if(profile->colored) colored_done = 1; + if(profile->bits == 16) numcolors_done = 1; + if(profile->bits >= bpp) bits_done = 1; + if(profile->numcolors >= maxnumcolors) numcolors_done = 1; + + if(!numcolors_done) { + for(i = 0; i < profile->numcolors; i++) { + const unsigned char* color = &profile->palette[i * 4]; + color_tree_add(&tree, color[0], color[1], color[2], color[3], (unsigned int)i); + } + } + + /*Check if the 16-bit input is truly 16-bit*/ + if(mode_in->bitdepth == 16 && !sixteen) { + unsigned short r, g, b, a; + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) || + (b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ { + profile->bits = 16; + sixteen = 1; + bits_done = 1; + numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/ + break; + } + } + } + + if(sixteen) { + unsigned short r = 0, g = 0, b = 0, a = 0; + + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + + if(!colored_done && (r != g || r != b)) { + profile->colored = 1; + colored_done = 1; + } + + if(!alpha_done) { + unsigned matchkey = (r == profile->key_r && g == profile->key_g && b == profile->key_b); + if(a != 65535 && (a != 0 || (profile->key && !matchkey))) { + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + } else if(a == 0 && !profile->alpha && !profile->key) { + profile->key = 1; + profile->key_r = r; + profile->key_g = g; + profile->key_b = b; + } else if(a == 65535 && profile->key && matchkey) { + /* Color key cannot be used if an opaque pixel also has that RGB color. */ + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + } + } + if(alpha_done && numcolors_done && colored_done && bits_done) break; + } + + if(profile->key && !profile->alpha) { + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + if(a != 0 && r == profile->key_r && g == profile->key_g && b == profile->key_b) { + /* Color key cannot be used if an opaque pixel also has that RGB color. */ + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + } + } + } + } else /* < 16-bit */ { + unsigned char r = 0, g = 0, b = 0, a = 0; + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); + + if(!bits_done && profile->bits < 8) { + /*only r is checked, < 8 bits is only relevant for grayscale*/ + unsigned bits = getValueRequiredBits(r); + if(bits > profile->bits) profile->bits = bits; + } + bits_done = (profile->bits >= bpp); + + if(!colored_done && (r != g || r != b)) { + profile->colored = 1; + colored_done = 1; + if(profile->bits < 8) profile->bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/ + } + + if(!alpha_done) { + unsigned matchkey = (r == profile->key_r && g == profile->key_g && b == profile->key_b); + if(a != 255 && (a != 0 || (profile->key && !matchkey))) { + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + if(profile->bits < 8) profile->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ + } else if(a == 0 && !profile->alpha && !profile->key) { + profile->key = 1; + profile->key_r = r; + profile->key_g = g; + profile->key_b = b; + } else if(a == 255 && profile->key && matchkey) { + /* Color key cannot be used if an opaque pixel also has that RGB color. */ + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + if(profile->bits < 8) profile->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ + } + } + + if(!numcolors_done) { + if(!color_tree_has(&tree, r, g, b, a)) { + color_tree_add(&tree, r, g, b, a, profile->numcolors); + if(profile->numcolors < 256) { + unsigned char* p = profile->palette; + unsigned n = profile->numcolors; + p[n * 4 + 0] = r; + p[n * 4 + 1] = g; + p[n * 4 + 2] = b; + p[n * 4 + 3] = a; + } + ++profile->numcolors; + numcolors_done = profile->numcolors >= maxnumcolors; + } + } + + if(alpha_done && numcolors_done && colored_done && bits_done) break; + } + + if(profile->key && !profile->alpha) { + for(i = 0; i != numpixels; ++i) { + getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); + if(a != 0 && r == profile->key_r && g == profile->key_g && b == profile->key_b) { + /* Color key cannot be used if an opaque pixel also has that RGB color. */ + profile->alpha = 1; + profile->key = 0; + alpha_done = 1; + if(profile->bits < 8) profile->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ + } + } + } + + /*make the profile's key always 16-bit for consistency - repeat each byte twice*/ + profile->key_r += (profile->key_r << 8); + profile->key_g += (profile->key_g << 8); + profile->key_b += (profile->key_b << 8); + } + + color_tree_cleanup(&tree); + return error; +} + +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS +/*Adds a single color to the color profile. The profile must already have been inited. The color must be given as 16-bit +(with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for +all pixels of an image but only for a few additional values. */ +static unsigned lodepng_color_profile_add(LodePNGColorProfile* profile, + unsigned r, unsigned g, unsigned b, unsigned a) { + unsigned error = 0; + unsigned char image[8]; + LodePNGColorMode mode; + lodepng_color_mode_init(&mode); + image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g; + image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a; + mode.bitdepth = 16; + mode.colortype = LCT_RGBA; + error = lodepng_get_color_profile(profile, image, 1, 1, &mode); + lodepng_color_mode_cleanup(&mode); + return error; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + +/*Autochoose color model given the computed profile. mode_in is to copy palette order from +when relevant.*/ +static unsigned auto_choose_color_from_profile(LodePNGColorMode* mode_out, + const LodePNGColorMode* mode_in, + const LodePNGColorProfile* prof) { + unsigned error = 0; + unsigned palettebits, palette_ok; + size_t i, n; + size_t numpixels = prof->numpixels; + + unsigned alpha = prof->alpha; + unsigned key = prof->key; + unsigned bits = prof->bits; + + mode_out->key_defined = 0; + + if(key && numpixels <= 16) { + alpha = 1; /*too few pixels to justify tRNS chunk overhead*/ + key = 0; + if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ + } + n = prof->numcolors; + palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8)); + palette_ok = n <= 256 && bits <= 8; + if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/ + if(!prof->colored && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/ + + if(palette_ok) { + const unsigned char* p = prof->palette; + lodepng_palette_clear(mode_out); /*remove potential earlier palette*/ + for(i = 0; i != prof->numcolors; ++i) { + error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]); + if(error) break; + } + + mode_out->colortype = LCT_PALETTE; + mode_out->bitdepth = palettebits; + + if(mode_in->colortype == LCT_PALETTE && mode_in->palettesize >= mode_out->palettesize + && mode_in->bitdepth == mode_out->bitdepth) { + /*If input should have same palette colors, keep original to preserve its order and prevent conversion*/ + lodepng_color_mode_cleanup(mode_out); + lodepng_color_mode_copy(mode_out, mode_in); + } + } else /*8-bit or 16-bit per channel*/ { + mode_out->bitdepth = bits; + mode_out->colortype = alpha ? (prof->colored ? LCT_RGBA : LCT_GREY_ALPHA) + : (prof->colored ? LCT_RGB : LCT_GREY); + + if(key) { + unsigned mask = (1u << mode_out->bitdepth) - 1u; /*profile always uses 16-bit, mask converts it*/ + mode_out->key_r = prof->key_r & mask; + mode_out->key_g = prof->key_g & mask; + mode_out->key_b = prof->key_b & mask; + mode_out->key_defined = 1; + } + } + + return error; +} + +/*Automatically chooses color type that gives smallest amount of bits in the +output image, e.g. gray if there are only grayscale pixels, palette if there +are less than 256 colors, color key if only single transparent color, ... +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.*/ +unsigned lodepng_auto_choose_color(LodePNGColorMode* mode_out, + const unsigned char* image, unsigned w, unsigned h, + const LodePNGColorMode* mode_in) { + unsigned error = 0; + LodePNGColorProfile prof; + lodepng_color_profile_init(&prof); + error = lodepng_get_color_profile(&prof, image, w, h, mode_in); + if(error) return error; + return auto_choose_color_from_profile(mode_out, mode_in, &prof); +} + +#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*/ + +/* +Outputs various dimensions and positions in the image related to the Adam7 reduced images. +passw: output containing the width of the 7 passes +passh: output containing the height of the 7 passes +filter_passstart: output containing the index of the start and end of each + reduced image with filter bytes +padded_passstart output containing the index of the start and end of each + reduced image when without filter bytes but with padded scanlines +passstart: output containing the index of the start and end of each reduced + image without padding between scanlines, but still padding between the images +w, h: width and height of non-interlaced image +bpp: bits per pixel +"padded" is only relevant if bpp is less than 8 and a scanline or image does not + end at a full byte +*/ +static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8], + size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) { + /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/ + unsigned i; + + /*calculate width and height in pixels of each pass*/ + for(i = 0; i != 7; ++i) { + passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i]; + passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i]; + if(passw[i] == 0) passh[i] = 0; + if(passh[i] == 0) passw[i] = 0; + } + + filter_passstart[0] = padded_passstart[0] = passstart[0] = 0; + for(i = 0; i != 7; ++i) { + /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/ + filter_passstart[i + 1] = filter_passstart[i] + + ((passw[i] && passh[i]) ? passh[i] * (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) { + unsigned width, height; + LodePNGInfo* info = &state->info_png; + if(insize == 0 || in == 0) { + CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/ + } + if(insize < 33) { + CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/ + } + + /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/ + /* TODO: remove this. One should use a new LodePNGState for new sessions */ + lodepng_info_cleanup(info); + lodepng_info_init(info); + + if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 + || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { + CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/ + } + if(lodepng_chunk_length(in + 8) != 13) { + CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/ + } + if(!lodepng_chunk_type_equals(in + 8, "IHDR")) { + CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/ + } + + /*read the values given in the header*/ + width = lodepng_read32bitInt(&in[16]); + height = lodepng_read32bitInt(&in[20]); + 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(width == 0 || height == 0) { + CERROR_RETURN_ERROR(state->error, 93); + } + + if(w) *w = width; + if(h) *h = height; + + 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] >> 1); + for(i = bytewidth; i < length; ++i) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) >> 1); + } else { + for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; + for(i = bytewidth; i < length; ++i) recon[i] = scanline[i] + (recon[i - bytewidth] >> 1); + } + 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; +} + +/* +in: Adam7 interlaced image, with no padding bits between scanlines, but between + reduced images so that each reduced image starts at a byte. +out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h +bpp: bits per pixel +out has the following size in bits: w * h * bpp. +in is possibly bigger due to padding bits between reduced images. +out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation +(because that's likely a little bit faster) +NOTE: comments about padding bits are only relevant if bpp < 8 +*/ +static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { + unsigned passw[7], passh[7]; + size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned i; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + if(bpp >= 8) { + for(i = 0; i != 7; ++i) { + unsigned x, y, b; + size_t bytewidth = bpp / 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 immediately filter into the out buffer, no other steps needed*/ + else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp)); + } else /*interlace_method is 1 (Adam7)*/ { + unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned i; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + for(i = 0; i != 7; ++i) { + CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp)); + /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline, + move bytes instead of bits or move not at all*/ + if(bpp < 8) { + /*remove padding bits in scanlines; after this there still may be padding + bits between the different reduced images: each reduced image still starts nicely at a byte*/ + removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp, + ((passw[i] * bpp + 7) / 8) * 8, passh[i]); + } + } + + Adam7_deinterlace(out, in, w, h, bpp); + } + + return 0; +} + +static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { + unsigned pos = 0, i; + if(color->palette) lodepng_free(color->palette); + color->palettesize = chunkLength / 3; + color->palette = (unsigned char*)lodepng_malloc(4 * color->palettesize); + if(!color->palette && color->palettesize) { + color->palettesize = 0; + return 83; /*alloc fail*/ + } + if(color->palettesize > 256) return 38; /*error: palette too big*/ + + for(i = 0; i != color->palettesize; ++i) { + color->palette[4 * i + 0] = data[pos++]; /*R*/ + color->palette[4 * i + 1] = data[pos++]; /*G*/ + color->palette[4 * i + 2] = data[pos++]; /*B*/ + color->palette[4 * i + 3] = 255; /*alpha*/ + } + + return 0; /* OK */ +} + +static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { + unsigned i; + if(color->colortype == LCT_PALETTE) { + /*error: more alpha values given than there are palette entries*/ + if(chunkLength > color->palettesize) return 39; + + for(i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i]; + } else if(color->colortype == LCT_GREY) { + /*error: this chunk must be 2 bytes for grayscale image*/ + if(chunkLength != 2) return 30; + + color->key_defined = 1; + color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1]; + } else if(color->colortype == LCT_RGB) { + /*error: this chunk must be 6 bytes for RGB image*/ + if(chunkLength != 6) return 41; + + color->key_defined = 1; + color->key_r = 256u * data[0] + data[1]; + color->key_g = 256u * data[2] + data[3]; + color->key_b = 256u * data[4] + data[5]; + } + else return 42; /*error: tRNS chunk not allowed for other color models*/ + + return 0; /* OK */ +} + + +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS +/*background color chunk (bKGD)*/ +static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(info->color.colortype == LCT_PALETTE) { + /*error: this chunk must be 1 byte for indexed color image*/ + if(chunkLength != 1) return 43; + + /*error: invalid palette index, or maybe this chunk appeared before PLTE*/ + if(data[0] >= info->color.palettesize) return 103; + + info->background_defined = 1; + info->background_r = info->background_g = info->background_b = data[0]; + } else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) { + /*error: this chunk must be 2 bytes for grayscale image*/ + if(chunkLength != 2) return 44; + + /*the values are truncated to bitdepth in the PNG file*/ + info->background_defined = 1; + info->background_r = info->background_g = info->background_b = 256u * data[0] + data[1]; + } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { + /*error: this chunk must be 6 bytes for grayscale image*/ + if(chunkLength != 6) return 45; + + /*the values are truncated to bitdepth in the PNG file*/ + info->background_defined = 1; + info->background_r = 256u * data[0] + data[1]; + info->background_g = 256u * data[2] + data[3]; + info->background_b = 256u * data[4] + data[5]; + } + + return 0; /* OK */ +} + +/*text chunk (tEXt)*/ +static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + unsigned error = 0; + char *key = 0, *str = 0; + unsigned i; + + while(!error) /*not really a while loop, only used to break on error*/ { + unsigned length, string2_begin; + + length = 0; + while(length < chunkLength && data[length] != 0) ++length; + /*even though it's not allowed by the standard, no error is thrown if + there's no null termination char, if the text is empty*/ + if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ + + key = (char*)lodepng_malloc(length + 1); + if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i != length; ++i) key[i] = (char)data[i]; + + string2_begin = length + 1; /*skip keyword null terminator*/ + + length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin); + str = (char*)lodepng_malloc(length + 1); + if(!str) CERROR_BREAK(error, 83); /*alloc fail*/ + + str[length] = 0; + for(i = 0; i != length; ++i) str[i] = (char)data[string2_begin + i]; + + error = lodepng_add_text(info, key, str); + + break; + } + + lodepng_free(key); + lodepng_free(str); + + return error; +} + +/*compressed text chunk (zTXt)*/ +static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecompressSettings* zlibsettings, + const unsigned char* data, size_t chunkLength) { + unsigned error = 0; + unsigned i; + + unsigned length, string2_begin; + char *key = 0; + ucvector decoded; + + ucvector_init(&decoded); + + while(!error) /*not really a while loop, only used to break on error*/ { + for(length = 0; length < chunkLength && data[length] != 0; ++length) ; + if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ + if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ + + key = (char*)lodepng_malloc(length + 1); + if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i != length; ++i) key[i] = (char)data[i]; + + if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ + + string2_begin = length + 2; + if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ + + length = (unsigned)chunkLength - string2_begin; + /*will fail if zlib error, e.g. if length is too small*/ + error = zlib_decompress(&decoded.data, &decoded.size, + (unsigned char*)(&data[string2_begin]), + length, zlibsettings); + if(error) break; + ucvector_push_back(&decoded, 0); + + error = lodepng_add_text(info, key, (char*)decoded.data); + + break; + } + + lodepng_free(key); + ucvector_cleanup(&decoded); + + return error; +} + +/*international text chunk (iTXt)*/ +static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecompressSettings* zlibsettings, + const unsigned char* data, size_t chunkLength) { + unsigned error = 0; + unsigned i; + + unsigned length, begin, compressed; + char *key = 0, *langtag = 0, *transkey = 0; + ucvector decoded; + ucvector_init(&decoded); /* TODO: only use in case of compressed text */ + + while(!error) /*not really a while loop, only used to break on error*/ { + /*Quick check if the chunk length isn't too small. Even without check + it'd still fail with other error checks below if it's too short. This just gives a different error code.*/ + if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/ + + /*read the key*/ + for(length = 0; length < chunkLength && data[length] != 0; ++length) ; + if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/ + if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ + + key = (char*)lodepng_malloc(length + 1); + if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ + + key[length] = 0; + for(i = 0; i != length; ++i) key[i] = (char)data[i]; + + /*read the compression method*/ + compressed = data[length + 1]; + if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ + + /*even though it's not allowed by the standard, no error is thrown if + there's no null termination char, if the text is empty for the next 3 texts*/ + + /*read the langtag*/ + begin = length + 3; + length = 0; + for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; + + langtag = (char*)lodepng_malloc(length + 1); + if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/ + + langtag[length] = 0; + for(i = 0; i != length; ++i) langtag[i] = (char)data[begin + i]; + + /*read the transkey*/ + begin += length + 1; + length = 0; + for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; + + transkey = (char*)lodepng_malloc(length + 1); + if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/ + + transkey[length] = 0; + for(i = 0; i != length; ++i) transkey[i] = (char)data[begin + i]; + + /*read the actual text*/ + begin += length + 1; + + length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin; + + if(compressed) { + /*will fail if zlib error, e.g. if length is too small*/ + error = zlib_decompress(&decoded.data, &decoded.size, + (unsigned char*)(&data[begin]), + length, zlibsettings); + if(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(error, 83 /*alloc fail*/); + + decoded.data[length] = 0; + for(i = 0; i != length; ++i) decoded.data[i] = data[begin + i]; + } + + error = lodepng_add_itext(info, key, langtag, transkey, (char*)decoded.data); + + break; + } + + lodepng_free(key); + lodepng_free(langtag); + lodepng_free(transkey); + ucvector_cleanup(&decoded); + + return error; +} + +static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(chunkLength != 7) return 73; /*invalid tIME chunk size*/ + + info->time_defined = 1; + info->time.year = 256u * data[0] + data[1]; + info->time.month = data[2]; + info->time.day = data[3]; + info->time.hour = data[4]; + info->time.minute = data[5]; + info->time.second = data[6]; + + return 0; /* OK */ +} + +static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/ + + info->phys_defined = 1; + info->phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; + info->phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7]; + info->phys_unit = data[8]; + + return 0; /* OK */ +} + +static unsigned readChunk_gAMA(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/ + + info->gama_defined = 1; + info->gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; + + return 0; /* OK */ +} + +static unsigned readChunk_cHRM(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/ + + info->chrm_defined = 1; + info->chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3]; + info->chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7]; + info->chrm_red_x = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11]; + info->chrm_red_y = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15]; + info->chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19]; + info->chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23]; + info->chrm_blue_x = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27]; + info->chrm_blue_y = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31]; + + return 0; /* OK */ +} + +static unsigned readChunk_sRGB(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { + if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/ + + info->srgb_defined = 1; + info->srgb_intent = data[0]; + + return 0; /* OK */ +} + +static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecompressSettings* zlibsettings, + const unsigned char* data, size_t chunkLength) { + unsigned error = 0; + unsigned i; + + unsigned length, string2_begin; + ucvector decoded; + + info->iccp_defined = 1; + if(info->iccp_name) lodepng_clear_icc(info); + + for(length = 0; length < chunkLength && data[length] != 0; ++length) ; + if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/ + if(length < 1 || length > 79) return 89; /*keyword too short or long*/ + + info->iccp_name = (char*)lodepng_malloc(length + 1); + if(!info->iccp_name) return 83; /*alloc fail*/ + + info->iccp_name[length] = 0; + for(i = 0; i != length; ++i) info->iccp_name[i] = (char)data[i]; + + if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/ + + string2_begin = length + 2; + if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/ + + length = (unsigned)chunkLength - string2_begin; + ucvector_init(&decoded); + error = zlib_decompress(&decoded.data, &decoded.size, + (unsigned char*)(&data[string2_begin]), + length, zlibsettings); + if(!error) { + info->iccp_profile_size = (unsigned int)decoded.size; + info->iccp_profile = (unsigned char*)lodepng_malloc(decoded.size); + if(info->iccp_profile) { + memcpy(info->iccp_profile, decoded.data, decoded.size); + } else { + error = 83; /* alloc fail */ + } + } + ucvector_cleanup(&decoded); + return error; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + +unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos, + const unsigned char* in, size_t insize) { + const unsigned char* chunk = in + pos; + unsigned chunkLength; + const unsigned char* data; + unsigned unhandled = 0; + unsigned error = 0; + + if (pos + 4 > insize) return 30; + chunkLength = lodepng_chunk_length(chunk); + if(chunkLength > 2147483647) return 63; + data = lodepng_chunk_data_const(chunk); + if(data + chunkLength + 4 > in + insize) return 30; + + if(lodepng_chunk_type_equals(chunk, "PLTE")) { + error = readChunk_PLTE(&state->info_png.color, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { + error = readChunk_tRNS(&state->info_png.color, data, chunkLength); +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { + error = readChunk_bKGD(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { + error = readChunk_tEXt(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { + error = readChunk_zTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { + error = readChunk_iTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "tIME")) { + error = readChunk_tIME(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { + error = readChunk_pHYs(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { + error = readChunk_gAMA(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { + error = readChunk_cHRM(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { + error = readChunk_sRGB(&state->info_png, data, chunkLength); + } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { + error = readChunk_iCCP(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } else { + /* unhandled chunk is ok (is not an error) */ + unhandled = 1; + } + + if(!error && !unhandled && !state->decoder.ignore_crc) { + if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/ + } + + return error; +} + +/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/ +static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h, + LodePNGState* state, + const unsigned char* in, size_t insize) { + unsigned char IEND = 0; + const unsigned char* chunk; + size_t i; + ucvector idat; /*the data from idat chunks*/ + ucvector scanlines; + size_t predict; + size_t outsize = 0; + + /*for unknown chunk order*/ + unsigned unknown = 0; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/ +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + + + /* safe output values in case error happens */ + *out = 0; + *w = *h = 0; + + state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/ + if(state->error) return; + + if(lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) { + CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/ + } + + 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) { + if(state->decoder.ignore_end) break; /*other errors may still happen though*/ + CERROR_BREAK(state->error, 30); + } + + /*length of the data of the chunk, excluding the 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) { + if(state->decoder.ignore_end) break; /*other errors may still happen though*/ + 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); + + unknown = 0; + + /*IDAT chunk, containing compressed image data*/ + if(lodepng_chunk_type_equals(chunk, "IDAT")) { + size_t oldsize = idat.size; + size_t newsize; + if(lodepng_addofl(oldsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95); + if(!ucvector_resize(&idat, newsize)) 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*/ + } else if(lodepng_chunk_type_equals(chunk, "IEND")) { + /*IEND chunk*/ + IEND = 1; + } else if(lodepng_chunk_type_equals(chunk, "PLTE")) { + /*palette chunk (PLTE)*/ + state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength); + if(state->error) break; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + critical_pos = 2; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { + /*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled + in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that + affects the alpha channel of pixels. */ + state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength); + if(state->error) break; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + /*background color chunk (bKGD)*/ + } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { + state->error = readChunk_bKGD(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { + /*text chunk (tEXt)*/ + if(state->decoder.read_text_chunks) { + state->error = readChunk_tEXt(&state->info_png, data, chunkLength); + if(state->error) break; + } + } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { + /*compressed text chunk (zTXt)*/ + if(state->decoder.read_text_chunks) { + state->error = readChunk_zTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); + if(state->error) break; + } + } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { + /*international text chunk (iTXt)*/ + if(state->decoder.read_text_chunks) { + state->error = readChunk_iTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); + if(state->error) break; + } + } else if(lodepng_chunk_type_equals(chunk, "tIME")) { + state->error = readChunk_tIME(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { + state->error = readChunk_pHYs(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { + state->error = readChunk_gAMA(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { + state->error = readChunk_cHRM(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { + state->error = readChunk_sRGB(&state->info_png, data, chunkLength); + if(state->error) break; + } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { + state->error = readChunk_iCCP(&state->info_png, &state->decoder.zlibsettings, data, chunkLength); + if(state->error) break; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } else /*it's not an implemented chunk type, so ignore it: skip over the data*/ { + /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/ + if(!state->decoder.ignore_critical && !lodepng_chunk_ancillary(chunk)) { + CERROR_BREAK(state->error, 69); + } + + unknown = 1; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + if(state->decoder.remember_unknown_chunks) { + state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1], + &state->info_png.unknown_chunks_size[critical_pos - 1], chunk); + if(state->error) break; + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + } + + if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/ { + if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/ + } + + if(!IEND) chunk = lodepng_chunk_next_const(chunk); + } + + ucvector_init(&scanlines); + /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation. + If the decompressed size does not match the prediction, the image must be corrupt.*/ + if(state->info_png.interlace_method == 0) { + predict = lodepng_get_raw_size_idat(*w, *h, &state->info_png.color); + } else { + /*Adam-7 interlaced: predicted size is the sum of the 7 sub-images sizes*/ + const LodePNGColorMode* color = &state->info_png.color; + predict = 0; + predict += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, color); + if(*w > 4) predict += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, color); + predict += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, color); + if(*w > 2) predict += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, color); + predict += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, color); + if(*w > 1) predict += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, color); + predict += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, color); + } + if(!state->error && !ucvector_reserve(&scanlines, predict)) state->error = 83; /*alloc fail*/ + if(!state->error) { + state->error = zlib_decompress(&scanlines.data, &scanlines.size, idat.data, + idat.size, &state->decoder.zlibsettings); + if(!state->error && scanlines.size != predict) state->error = 91; /*decompressed size doesn't match prediction*/ + } + ucvector_cleanup(&idat); + + if(!state->error) { + outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color); + *out = (unsigned char*)lodepng_malloc(outsize); + if(!*out) state->error = 83; /*alloc fail*/ + } + if(!state->error) { + for(i = 0; i < outsize; i++) (*out)[i] = 0; + state->error = postProcessScanlines(*out, scanlines.data, *w, *h, &state->info_png); + } + ucvector_cleanup(&scanlines); +} + +unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, + LodePNGState* state, + const unsigned char* in, size_t insize) { + *out = 0; + decodeGeneric(out, w, h, state, in, insize); + if(state->error) return state->error; + if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) { + /*same color type, no copying or converting of data needed*/ + /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype + the raw image has to the end user*/ + if(!state->decoder.color_convert) { + state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color); + if(state->error) return state->error; + } + } else { + /*color conversion needed; 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 grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/ + if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA) + && !(state->info_raw.bitdepth == 8)) { + return 56; /*unsupported color mode conversion*/ + } + + outsize = lodepng_get_raw_size(*w, *h, &state->info_raw); + *out = (unsigned char*)lodepng_malloc(outsize); + if(!(*out)) { + state->error = 83; /*alloc fail*/ + } + else state->error = lodepng_convert(*out, data, &state->info_raw, + &state->info_png.color, *w, *h); + lodepng_free(data); + } + return state->error; +} + +unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, + size_t insize, LodePNGColorType colortype, unsigned bitdepth) { + unsigned error; + LodePNGState state; + lodepng_state_init(&state); + state.info_raw.colortype = colortype; + state.info_raw.bitdepth = bitdepth; + error = lodepng_decode(out, w, h, &state, in, insize); + lodepng_state_cleanup(&state); + return error; +} + +unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { + return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8); +} + +unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { + return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8); +} + +#ifdef LODEPNG_COMPILE_DISK +unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename, + LodePNGColorType colortype, unsigned bitdepth) { + unsigned char* buffer = 0; + size_t buffersize; + unsigned error; + /* safe output values in case error happens */ + *out = 0; + *w = *h = 0; + error = lodepng_load_file(&buffer, &buffersize, filename); + if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth); + lodepng_free(buffer); + return error; +} + +unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { + return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8); +} + +unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { + return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8); +} +#endif /*LODEPNG_COMPILE_DISK*/ + +void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) { + settings->color_convert = 1; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + settings->read_text_chunks = 1; + settings->remember_unknown_chunks = 0; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + settings->ignore_crc = 0; + settings->ignore_critical = 0; + settings->ignore_end = 0; + lodepng_decompress_settings_init(&settings->zlibsettings); +} + +#endif /*LODEPNG_COMPILE_DECODER*/ + +#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) + +void lodepng_state_init(LodePNGState* state) { +#ifdef LODEPNG_COMPILE_DECODER + lodepng_decoder_settings_init(&state->decoder); +#endif /*LODEPNG_COMPILE_DECODER*/ +#ifdef LODEPNG_COMPILE_ENCODER + lodepng_encoder_settings_init(&state->encoder); +#endif /*LODEPNG_COMPILE_ENCODER*/ + lodepng_color_mode_init(&state->info_raw); + lodepng_info_init(&state->info_png); + state->error = 1; +} + +void lodepng_state_cleanup(LodePNGState* state) { + lodepng_color_mode_cleanup(&state->info_raw); + lodepng_info_cleanup(&state->info_png); +} + +void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source) { + lodepng_state_cleanup(dest); + *dest = *source; + lodepng_color_mode_init(&dest->info_raw); + lodepng_info_init(&dest->info_png); + dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return; + dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); if(dest->error) return; +} + +#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */ + +#ifdef LODEPNG_COMPILE_ENCODER + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / PNG Encoder / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/*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 >> 8)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_r & 255)); + } + } else if(info->colortype == LCT_RGB) { + if(info->key_defined) { + ucvector_push_back(&tRNS, (unsigned char)(info->key_r >> 8)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_r & 255)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_g >> 8)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_g & 255)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_b >> 8)); + ucvector_push_back(&tRNS, (unsigned char)(info->key_b & 255)); + } + } + + 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 = 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]); + if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/ + ucvector_push_back(&text, 0); /*0 termination char*/ + 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]); + if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/ + ucvector_push_back(&data, 0); /*0 termination char*/ + ucvector_push_back(&data, 0); /*compression method: 0*/ + + error = 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]); + if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/ + 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 = 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 >> 8)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_r & 255)); + } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { + ucvector_push_back(&bKGD, (unsigned char)(info->background_r >> 8)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_r & 255)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_g >> 8)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_g & 255)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_b >> 8)); + ucvector_push_back(&bKGD, (unsigned char)(info->background_b & 255)); + } else if(info->color.colortype == LCT_PALETTE) { + ucvector_push_back(&bKGD, (unsigned char)(info->background_r & 255)); /*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*)lodepng_malloc(7); + if(!data) return 83; /*alloc fail*/ + data[0] = (unsigned char)(time->year >> 8); + data[1] = (unsigned char)(time->year & 255); + data[2] = (unsigned char)time->month; + data[3] = (unsigned char)time->day; + data[4] = (unsigned char)time->hour; + data[5] = (unsigned char)time->minute; + data[6] = (unsigned char)time->second; + error = addChunk(out, "tIME", data, 7); + lodepng_free(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; +} + +static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) { + unsigned error = 0; + ucvector data; + ucvector_init(&data); + + lodepng_add32bitInt(&data, info->gama_gamma); + + error = addChunk(out, "gAMA", data.data, data.size); + ucvector_cleanup(&data); + + return error; +} + +static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) { + unsigned error = 0; + ucvector data; + ucvector_init(&data); + + lodepng_add32bitInt(&data, info->chrm_white_x); + lodepng_add32bitInt(&data, info->chrm_white_y); + lodepng_add32bitInt(&data, info->chrm_red_x); + lodepng_add32bitInt(&data, info->chrm_red_y); + lodepng_add32bitInt(&data, info->chrm_green_x); + lodepng_add32bitInt(&data, info->chrm_green_y); + lodepng_add32bitInt(&data, info->chrm_blue_x); + lodepng_add32bitInt(&data, info->chrm_blue_y); + + error = addChunk(out, "cHRM", data.data, data.size); + ucvector_cleanup(&data); + + return error; +} + +static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) { + unsigned char data = info->srgb_intent; + return addChunk(out, "sRGB", &data, 1); +} + +static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, LodePNGCompressSettings* zlibsettings) { + unsigned error = 0; + ucvector data, compressed; + size_t i; + + ucvector_init(&data); + ucvector_init(&compressed); + for(i = 0; info->iccp_name[i] != 0; ++i) ucvector_push_back(&data, (unsigned char)info->iccp_name[i]); + if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/ + ucvector_push_back(&data, 0); /*0 termination char*/ + ucvector_push_back(&data, 0); /*compression method: 0*/ + + error = zlib_compress(&compressed.data, &compressed.size, + info->iccp_profile, info->iccp_profile_size, zlibsettings); + if(!error) { + for(i = 0; i != compressed.size; ++i) ucvector_push_back(&data, compressed.data[i]); + error = addChunk(out, "iCCP", data.data, data.size); + } + + ucvector_cleanup(&compressed); + 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*/ + for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; + for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth]; + break; + case 2: /*Up*/ + if(prevline) { + for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i]; + } else { + for(i = 0; i != length; ++i) out[i] = scanline[i]; + } + break; + case 3: /*Average*/ + if(prevline) { + for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1); + for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1); + } else { + for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; + for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1); + } + break; + case 4: /*Paeth*/ + if(prevline) { + /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/ + for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]); + for(i = bytewidth; i < length; ++i) { + out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth])); + } + } else { + for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; + /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/ + for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]); + } + break; + default: return; /*unexisting filter type given*/ + } +} + +/* log2 approximation. A slight bit faster than std::log. */ +static float flog2(float f) { + float result = 0; + while(f > 32) { result += 4; f /= 16; } + while(f > 2) { ++result; f /= 2; } + return result + 1.442695f * (f * f * f / 3 - 3 * f * f / 2 + 3 * f - 1.83333f); +} + +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; + LodePNGFilterStrategy strategy = settings->filter_strategy; + + /* + There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard: + * If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e. + use fixed filtering, with the filter None). + * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is + not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply + all five filters and select the filter that produces the smallest sum of absolute values per row. + This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true. + + If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed, + but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum + heuristic is used. + */ + if(settings->filter_palette_zero && + (info->colortype == LCT_PALETTE || info->bitdepth < 8)) strategy = LFS_ZERO; + + if(bpp == 0) return 31; /*error: invalid color type*/ + + if(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; + out[outindex] = 0; /*filter type byte*/ + filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, 0); + prevline = &in[inindex]; + } + } else if(strategy == LFS_MINSUM) { + /*adaptive filtering*/ + size_t sum[5]; + unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ + size_t smallest = 0; + unsigned char type, bestType = 0; + + for(type = 0; type != 5; ++type) { + attempt[type] = (unsigned char*)lodepng_malloc(linebytes); + if(!attempt[type]) return 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], &in[y * linebytes], prevline, linebytes, bytewidth, type); + + /*calculate the sum of the result*/ + sum[type] = 0; + if(type == 0) { + for(x = 0; x != linebytes; ++x) sum[type] += (unsigned char)(attempt[type][x]); + } else { + for(x = 0; x != linebytes; ++x) { + /*For differences, each byte should be treated as signed, values above 127 are negative + (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there. + This means filtertype 0 is almost never chosen, but that is justified.*/ + unsigned char s = attempt[type][x]; + sum[type] += s < 128 ? s : (255U - s); + } + } + + /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/ + if(type == 0 || sum[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][x]; + } + } + + for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); + } else if(strategy == LFS_ENTROPY) { + float sum[5]; + unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ + float smallest = 0; + unsigned type, bestType = 0; + unsigned count[256]; + + for(type = 0; type != 5; ++type) { + attempt[type] = (unsigned char*)lodepng_malloc(linebytes); + if(!attempt[type]) return 83; /*alloc fail*/ + } + + for(y = 0; y != h; ++y) { + /*try the 5 filter types*/ + for(type = 0; type != 5; ++type) { + filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); + for(x = 0; x != 256; ++x) count[x] = 0; + for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]]; + ++count[type]; /*the filter type itself is part of the scanline*/ + sum[type] = 0; + for(x = 0; x != 256; ++x) { + float p = count[x] / (float)(linebytes + 1); + sum[type] += count[x] == 0 ? 0 : flog2(1 / p) * p; + } + /*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][x]; + } + + for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); + } else if(strategy == LFS_PREDEFINED) { + for(y = 0; y != h; ++y) { + size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ + size_t inindex = linebytes * y; + unsigned char type = settings->predefined_filters[y]; + out[outindex] = type; /*filter type byte*/ + filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type); + prevline = &in[inindex]; + } + } else if(strategy == LFS_BRUTE_FORCE) { + /*brute force filter chooser. + deflate the scanline after every filter attempt to see which one deflates best. + This is very slow and gives only slightly smaller, sometimes even larger, result*/ + size_t size[5]; + unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ + size_t smallest = 0; + unsigned type = 0, bestType = 0; + unsigned char* dummy; + LodePNGCompressSettings zlibsettings = 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_zlib = 0; + zlibsettings.custom_deflate = 0; + for(type = 0; type != 5; ++type) { + attempt[type] = (unsigned char*)lodepng_malloc(linebytes); + if(!attempt[type]) return 83; /*alloc fail*/ + } + for(y = 0; y != h; ++y) /*try the 5 filter types*/ { + for(type = 0; type != 5; ++type) { + unsigned testsize = (unsigned)linebytes; + /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/ + + filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); + size[type] = 0; + dummy = 0; + zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings); + lodepng_free(dummy); + /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/ + if(type == 0 || size[type] < smallest) { + bestType = type; + smallest = size[type]; + } + } + prevline = &in[y * linebytes]; + out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ + for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; + } + for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); + } + else return 88; /* unknown filter strategy */ + + return error; +} + +static void addPaddingBits(unsigned char* out, const unsigned char* in, + size_t olinebits, size_t ilinebits, unsigned h) { + /*The opposite of the removePaddingBits function + olinebits must be >= ilinebits*/ + unsigned y; + size_t diff = olinebits - ilinebits; + size_t obp = 0, ibp = 0; /*bit pointers*/ + for(y = 0; y != h; ++y) { + size_t x; + for(x = 0; x < ilinebits; ++x) { + unsigned char bit = readBitFromReversedStream(&ibp, in); + setBitOfReversedStream(&obp, out, bit); + } + /*obp += diff; --> no, fill in some value in the padding bits too, to avoid + "Use of uninitialised value of size ###" warning from valgrind*/ + for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0); + } +} + +/* +in: non-interlaced image with size w*h +out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with + no padding bits between scanlines, but between reduced images so that each + reduced image starts at a byte. +bpp: bits per pixel +there are no padding bits, not between scanlines, not between reduced images +in has the following size in bits: w * h * bpp. +out is possibly bigger due to padding bits between reduced images +NOTE: comments about padding bits are only relevant if bpp < 8 +*/ +static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { + unsigned passw[7], passh[7]; + size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned i; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + if(bpp >= 8) { + for(i = 0; i != 7; ++i) { + unsigned x, y, b; + size_t bytewidth = bpp / 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*)lodepng_malloc(*outsize); + if(!(*out) && (*outsize)) error = 83; /*alloc fail*/ + + if(!error) { + /*non multiple of 8 bits per scanline, padding bits needed per scanline*/ + if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8) { + unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7) / 8)); + if(!padded) error = 83; /*alloc fail*/ + if(!error) { + addPaddingBits(padded, in, ((w * bpp + 7) / 8) * 8, w * bpp, h); + error = filter(*out, padded, w, h, &info_png->color, settings); + } + lodepng_free(padded); + } else { + /*we can immediately filter into the out buffer, no other steps needed*/ + error = filter(*out, in, w, h, &info_png->color, settings); + } + } + } else /*interlace_method is 1 (Adam7)*/ { + unsigned passw[7], passh[7]; + size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned char* adam7; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/ + *out = (unsigned char*)lodepng_malloc(*outsize); + if(!(*out)) error = 83; /*alloc fail*/ + + adam7 = (unsigned char*)lodepng_malloc(passstart[7]); + if(!adam7 && passstart[7]) error = 83; /*alloc fail*/ + + if(!error) { + unsigned i; + + Adam7_interlace(adam7, in, w, h, bpp); + for(i = 0; i != 7; ++i) { + if(bpp < 8) { + unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]); + if(!padded) ERROR_BREAK(83); /*alloc fail*/ + addPaddingBits(padded, &adam7[passstart[i]], + ((passw[i] * bpp + 7) / 8) * 8, passw[i] * bpp, passh[i]); + error = filter(&(*out)[filter_passstart[i]], padded, + passw[i], passh[i], &info_png->color, settings); + lodepng_free(padded); + } else { + error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]], + passw[i], passh[i], &info_png->color, settings); + } + + if(error) break; + } + } + + lodepng_free(adam7); + } + + return error; +} + +/* +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; + unsigned key = 0; + unsigned r = 0, g = 0, b = 0; /*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; +} + +static unsigned isGrayICCProfile(const unsigned char* profile, unsigned size) { + /* + It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19 + are "RGB ". We do not perform any full parsing of the ICC profile here, other + than check those 4 bytes to grayscale profile. Other than that, validity of + the profile is not checked. This is needed only because the PNG specification + requires using a non-gray color model if there is an ICC profile with "RGB " + (sadly limiting compression opportunities if the input data is grayscale RGB + data), and requires using a gray color model if it is "GRAY". + */ + if(size < 20) return 0; + return profile[16] == 'G' && profile[17] == 'R' && profile[18] == 'A' && profile[19] == 'Y'; +} + +static unsigned isRGBICCProfile(const unsigned char* profile, unsigned size) { + /* See comment in isGrayICCProfile*/ + if(size < 20) return 0; + return profile[16] == 'R' && profile[17] == 'G' && profile[18] == 'B' && profile[19] == ' '; +} +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + +unsigned lodepng_encode(unsigned char** out, size_t* outsize, + const unsigned char* image, unsigned w, unsigned h, + LodePNGState* state) { + unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/ + size_t datasize = 0; + ucvector outv; + LodePNGInfo info; + + ucvector_init(&outv); + lodepng_info_init(&info); + + /*provide some proper output values if error will happen*/ + *out = 0; + *outsize = 0; + state->error = 0; + + /*check input values validity*/ + if((state->info_png.color.colortype == LCT_PALETTE || state->encoder.force_palette) + && (state->info_png.color.palettesize == 0 || state->info_png.color.palettesize > 256)) { + state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/ + goto cleanup; + } + if(state->encoder.zlibsettings.btype > 2) { + state->error = 61; /*error: unexisting btype*/ + goto cleanup; + } + if(state->info_png.interlace_method > 1) { + state->error = 71; /*error: unexisting interlace mode*/ + goto cleanup; + } + state->error = checkColorValidity(state->info_png.color.colortype, state->info_png.color.bitdepth); + if(state->error) goto cleanup; /*error: unexisting color type given*/ + state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth); + if(state->error) goto cleanup; /*error: unexisting color type given*/ + + /* color convert and compute scanline filter types */ + lodepng_info_copy(&info, &state->info_png); + if(state->encoder.auto_convert) { +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + if(state->info_png.background_defined) { + unsigned bg_r = state->info_png.background_r; + unsigned bg_g = state->info_png.background_g; + unsigned bg_b = state->info_png.background_b; + unsigned r = 0, g = 0, b = 0; + LodePNGColorProfile prof; + LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16); + lodepng_convert_rgb(&r, &g, &b, bg_r, bg_g, bg_b, &mode16, &state->info_png.color); + lodepng_color_profile_init(&prof); + state->error = lodepng_get_color_profile(&prof, image, w, h, &state->info_raw); + if(state->error) goto cleanup; + lodepng_color_profile_add(&prof, r, g, b, 65535); + state->error = auto_choose_color_from_profile(&info.color, &state->info_raw, &prof); + if(state->error) goto cleanup; + if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b, + bg_r, bg_g, bg_b, &info.color, &state->info_png.color)) { + state->error = 104; + goto cleanup; + } + } + else +#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ + { + state->error = lodepng_auto_choose_color(&info.color, image, w, h, &state->info_raw); + if(state->error) goto cleanup; + } + } +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + if(state->info_png.iccp_defined) { + unsigned gray_icc = isGrayICCProfile(state->info_png.iccp_profile, state->info_png.iccp_profile_size); + unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA; + /* TODO: perhaps instead of giving errors or less optimal compression, we can automatically modify + the ICC profile here to say "GRAY" or "RGB " to match the PNG color type, unless this will require + non trivial changes to the rest of the ICC profile */ + if(!gray_icc && !isRGBICCProfile(state->info_png.iccp_profile, state->info_png.iccp_profile_size)) { + state->error = 100; /* Disallowed profile color type for PNG */ + goto cleanup; + } + if(!state->encoder.auto_convert && gray_icc != gray_png) { + /* Non recoverable: encoder not allowed to convert color type, and requested color type not + compatible with ICC color type */ + state->error = 101; + goto cleanup; + } + if(gray_icc && !gray_png) { + /* Non recoverable: trying to set grayscale ICC profile while colored pixels were given */ + state->error = 102; + goto cleanup; + /* NOTE: this relies on the fact that lodepng_auto_choose_color never returns palette for grayscale pixels */ + } + if(!gray_icc && gray_png) { + /* Recoverable but an unfortunate loss in compression density: We have grayscale pixels but + are forced to store them in more expensive RGB format that will repeat each value 3 times + because the PNG spec does not allow an RGB ICC profile with internal grayscale color data */ + if(info.color.colortype == LCT_GREY) info.color.colortype = LCT_RGB; + if(info.color.colortype == LCT_GREY_ALPHA) info.color.colortype = LCT_RGBA; + if(info.color.bitdepth < 8) info.color.bitdepth = 8; + } + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) { + unsigned char* converted; + size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7) / 8; + + converted = (unsigned char*)lodepng_malloc(size); + if(!converted && size) state->error = 83; /*alloc fail*/ + if(!state->error) { + state->error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h); + } + if(!state->error) preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder); + lodepng_free(converted); + if(state->error) goto cleanup; + } + else preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder); + + /* output all PNG chunks */ { +#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) goto cleanup; + } + /*color profile chunks must come before PLTE */ + if(info.iccp_defined) addChunk_iCCP(&outv, &info, &state->encoder.zlibsettings); + if(info.srgb_defined) addChunk_sRGB(&outv, &info); + if(info.gama_defined) addChunk_gAMA(&outv, &info); + if(info.chrm_defined) addChunk_cHRM(&outv, &info); +#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) { + state->error = addChunk_bKGD(&outv, &info); + if(state->error) goto cleanup; + } + /*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) goto cleanup; + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + /*IDAT (multiple IDAT chunks must be consecutive)*/ + state->error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings); + if(state->error) goto cleanup; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + /*tIME*/ + if(info.time_defined) 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*/ + goto cleanup; + } + if(strlen(info.text_keys[i]) < 1) { + state->error = 67; /*text chunk too small*/ + goto cleanup; + } + 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 already_added_id_text = 0; + for(i = 0; i != info.text_num; ++i) { + if(!strcmp(info.text_keys[i], "LodePNG")) { + already_added_id_text = 1; + break; + } + } + if(already_added_id_text == 0) { + addChunk_tEXt(&outv, "LodePNG", 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*/ + goto cleanup; + } + if(strlen(info.itext_keys[i]) < 1) { + state->error = 67; /*text chunk too small*/ + goto cleanup; + } + 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) goto cleanup; + } +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ + addChunk_IEND(&outv); + } + +cleanup: + lodepng_info_cleanup(&info); + lodepng_free(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); + lodepng_free(buffer); + return error; +} + +unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { + return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8); +} + +unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { + return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8); +} +#endif /*LODEPNG_COMPILE_DISK*/ + +void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) { + lodepng_compress_settings_init(&settings->zlibsettings); + settings->filter_palette_zero = 1; + settings->filter_strategy = LFS_MINSUM; + settings->auto_convert = 1; + settings->force_palette = 0; + settings->predefined_filters = 0; +#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS + settings->add_id = 0; + settings->text_compression = 1; +#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ +} + +#endif /*LODEPNG_COMPILE_ENCODER*/ +#endif /*LODEPNG_COMPILE_PNG*/ + +#ifdef LODEPNG_COMPILE_ERROR_TEXT +/* +This returns the description of a numerical error code in English. This is also +the documentation of all the error codes. +*/ +const char* lodepng_error_text(unsigned code) { + switch(code) { + case 0: return "no error, everything went ok"; + case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/ + case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/ + case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/ + case 13: return "problem while processing dynamic deflate block"; + case 14: return "problem while processing dynamic deflate block"; + case 15: return "problem while processing dynamic deflate block"; + 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 "tRNS chunk before PLTE or has more entries than palette size"; + case 40: return "tRNS chunk has wrong size for grayscale image"; + case 41: return "tRNS chunk has wrong size for RGB image"; + case 42: return "tRNS chunk appeared while it was not allowed for this color type"; + case 43: return "bKGD chunk has wrong size for palette image"; + case 44: return "bKGD chunk has wrong size for grayscale image"; + case 45: return "bKGD chunk has wrong size for RGB image"; + case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?"; + case 49: return "jumped past memory while generating dynamic huffman tree"; + case 50: return "jumped past memory while generating dynamic huffman tree"; + case 51: return "jumped past memory while inflating huffman block"; + case 52: return "jumped past memory while inflating"; + case 53: return "size of zlib data too small"; + case 54: return "repeat symbol in tree while there was no value symbol yet"; + /*jumped past tree while generating huffman tree, this could be when the + tree will have more leaves than symbols after generating it out of the + given 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 grayscale conversion formula to the user.*/ + case 62: return "conversion from color to grayscale not supported"; + /*(2^31-1)*/ + case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk"; + /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/ + case 64: return "the length of the END symbol 256 in the Huffman tree is 0"; + case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes"; + case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte"; + case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors"; + case 69: return "unknown chunk type with 'critical' flag encountered by the decoder"; + case 71: return "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, or index out of bounds"; + case 83: return "memory allocation failed"; + case 84: return "given image too small to contain all pixels to be encoded"; + case 86: return "impossible offset in lz77 encoding (internal bug)"; + case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined"; + case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy"; + case 89: return "text chunk keyword too short or long: must have size 1-79"; + /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/ + case 90: return "windowsize must be a power of two"; + case 91: return "invalid decompressed idat size"; + case 92: return "integer overflow due to too many pixels"; + case 93: return "zero width or height is invalid"; + case 94: return "header chunk must have a size of 13 bytes"; + case 95: return "integer overflow with combined idat chunk size"; + case 96: return "invalid gAMA chunk size"; + case 97: return "invalid cHRM chunk size"; + case 98: return "invalid sRGB chunk size"; + case 99: return "invalid sRGB rendering intent"; + case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY"; + case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa"; + case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification"; + case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?"; + case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)"; + } + return "unknown error code"; +} +#endif /*LODEPNG_COMPILE_ERROR_TEXT*/ + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // C++ Wrapper // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#ifdef LODEPNG_COMPILE_CPP +namespace lodepng { + +#ifdef LODEPNG_COMPILE_DISK +unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename) { + long size = lodepng_filesize(filename.c_str()); + if(size < 0) return 78; + buffer.resize((size_t)size); + return size == 0 ? 0 : lodepng_buffer_file(&buffer[0], (size_t)size, filename.c_str()); +} + +/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ +unsigned save_file(const std::vector<unsigned char>& buffer, const std::string& filename) { + return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str()); +} +#endif /* LODEPNG_COMPILE_DISK */ + +#ifdef LODEPNG_COMPILE_ZLIB +#ifdef LODEPNG_COMPILE_DECODER +unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize, + const LodePNGDecompressSettings& settings) { + unsigned char* buffer = 0; + size_t buffersize = 0; + unsigned error = zlib_decompress(&buffer, &buffersize, in, insize, &settings); + if(buffer) { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + lodepng_free(buffer); + } + return error; +} + +unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, + const LodePNGDecompressSettings& settings) { + return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings); +} +#endif /* LODEPNG_COMPILE_DECODER */ + +#ifdef LODEPNG_COMPILE_ENCODER +unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize, + const LodePNGCompressSettings& settings) { + unsigned char* buffer = 0; + size_t buffersize = 0; + unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings); + if(buffer) { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + lodepng_free(buffer); + } + return error; +} + +unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, + const LodePNGCompressSettings& settings) { + return compress(out, in.empty() ? 0 : &in[0], in.size(), settings); +} +#endif /* LODEPNG_COMPILE_ENCODER */ +#endif /* LODEPNG_COMPILE_ZLIB */ + + +#ifdef LODEPNG_COMPILE_PNG + +State::State() { + lodepng_state_init(this); +} + +State::State(const State& other) { + lodepng_state_init(this); + lodepng_state_copy(this, &other); +} + +State::~State() { + lodepng_state_cleanup(this); +} + +State& State::operator=(const State& other) { + lodepng_state_copy(this, &other); + return *this; +} + +#ifdef LODEPNG_COMPILE_DECODER + +unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const unsigned char* in, + size_t insize, LodePNGColorType colortype, unsigned bitdepth) { + unsigned char* buffer; + 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]); + lodepng_free(buffer); + } + return error; +} + +unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, + const std::vector<unsigned char>& in, LodePNGColorType colortype, unsigned bitdepth) { + return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth); +} + +unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, + State& state, + const unsigned char* in, size_t insize) { + unsigned char* buffer = NULL; + unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize); + if(buffer && !error) { + size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw); + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + } + lodepng_free(buffer); + return error; +} + +unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, + State& state, + const std::vector<unsigned char>& in) { + return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size()); +} + +#ifdef LODEPNG_COMPILE_DISK +unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename, + LodePNGColorType colortype, unsigned bitdepth) { + std::vector<unsigned char> buffer; + /* safe output values in case error happens */ + w = h = 0; + unsigned error = load_file(buffer, filename); + if(error) return error; + return decode(out, w, h, buffer, colortype, bitdepth); +} +#endif /* LODEPNG_COMPILE_DECODER */ +#endif /* LODEPNG_COMPILE_DISK */ + +#ifdef LODEPNG_COMPILE_ENCODER +unsigned encode(std::vector<unsigned char>& out, const unsigned char* in, unsigned w, unsigned h, + LodePNGColorType colortype, unsigned bitdepth) { + unsigned char* buffer; + size_t buffersize; + unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth); + if(buffer) { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + lodepng_free(buffer); + } + return error; +} + +unsigned encode(std::vector<unsigned char>& out, + const std::vector<unsigned char>& in, unsigned w, unsigned h, + LodePNGColorType colortype, unsigned bitdepth) { + if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; + return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); +} + +unsigned encode(std::vector<unsigned char>& out, + const unsigned char* in, unsigned w, unsigned h, + State& state) { + unsigned char* buffer; + size_t buffersize; + unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state); + if(buffer) { + out.insert(out.end(), &buffer[0], &buffer[buffersize]); + lodepng_free(buffer); + } + return error; +} + +unsigned encode(std::vector<unsigned char>& out, + const std::vector<unsigned char>& in, unsigned w, unsigned h, + State& state) { + if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84; + return encode(out, in.empty() ? 0 : &in[0], w, h, state); +} + +#ifdef LODEPNG_COMPILE_DISK +unsigned encode(const std::string& filename, + const unsigned char* in, unsigned w, unsigned h, + LodePNGColorType colortype, unsigned bitdepth) { + std::vector<unsigned char> buffer; + unsigned error = encode(buffer, in, w, h, colortype, bitdepth); + if(!error) error = save_file(buffer, filename); + return error; +} + +unsigned encode(const std::string& filename, + const std::vector<unsigned char>& in, unsigned w, unsigned h, + LodePNGColorType colortype, unsigned bitdepth) { + if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; + return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); +} +#endif /* LODEPNG_COMPILE_DISK */ +#endif /* LODEPNG_COMPILE_ENCODER */ +#endif /* LODEPNG_COMPILE_PNG */ +} /* namespace lodepng */ +#endif /*LODEPNG_COMPILE_CPP*/ |