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Diffstat (limited to 'thirdparty/thorvg/src/loaders/png/tvgLodePng.cpp')
| -rw-r--r-- | thirdparty/thorvg/src/loaders/png/tvgLodePng.cpp | 2647 |
1 files changed, 2647 insertions, 0 deletions
diff --git a/thirdparty/thorvg/src/loaders/png/tvgLodePng.cpp b/thirdparty/thorvg/src/loaders/png/tvgLodePng.cpp new file mode 100644 index 0000000000..f2dfa02875 --- /dev/null +++ b/thirdparty/thorvg/src/loaders/png/tvgLodePng.cpp @@ -0,0 +1,2647 @@ +/* + * Copyright (c) 2020-2021 Samsung Electronics Co., Ltd. All rights reserved. + + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +/* + LodePNG version 20200306 + + Copyright (c) 2005-2020 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 sourcedistribution. +*/ + +#include <cstdlib> +#include "tvgLodePng.h" + + +/************************************************************************/ +/* Internal Class Implementation */ +/************************************************************************/ + +#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 */ + + +/* convince the compiler to inline a function, for use when this measurably improves performance */ +/* inline is not available in C90, but use it when supported by the compiler */ +#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L)) + #define LODEPNG_INLINE inline +#else + #define LODEPNG_INLINE /* not available */ +#endif + +/* restrict is not available in C90, but use it when supported by the compiler */ +#if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\ + (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \ + (defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus)) + #define LODEPNG_RESTRICT __restrict +#else + #define LODEPNG_RESTRICT /* not available */ +#endif + +#define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b)) +#define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b)) +#define LODEPNG_ABS(x) ((x) < 0 ? -(x) : (x)) + + +/* Replacements for C library functions such as memcpy and strlen, to support platforms +where a full C library is not available. The compiler can recognize them and compile +to something as fast. */ + +static void lodepng_memcpy(void* LODEPNG_RESTRICT dst, const void* LODEPNG_RESTRICT src, size_t size) +{ + size_t i; + for (i = 0; i < size; i++) ((char*)dst)[i] = ((const char*)src)[i]; +} + + +static void lodepng_memset(void* LODEPNG_RESTRICT dst, int value, size_t num) +{ + size_t i; + for (i = 0; i < num; i++) ((char*)dst)[i] = (char)value; +} + + +/* does not check memory out of bounds, do not use on untrusted data */ +static size_t lodepng_strlen(const char* a) +{ + const char* orig = a; + /* avoid warning about unused function in case of disabled COMPILE... macros */ + (void)(&lodepng_strlen); + while (*a) a++; + return (size_t)(a - orig); +} + + +/* 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 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 a + b > c, even if overflow could happen. */ +static int lodepng_gtofl(size_t a, size_t b, size_t c) +{ + size_t d; + if (lodepng_addofl(a, b, &d)) return 1; + return d > c; +} + + +/* + Often in case of an error a value is assigned to a variable and then it breaks + out of a loop (to go to the cleanup phase of a function). This macro does that. + It makes the error handling code shorter and more readable. + + Example: if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83); +*/ +#define CERROR_BREAK(errorvar, code){\ + errorvar = code;\ + break;\ +} + +/* version of CERROR_BREAK that assumes the common case where the error variable is named "error" */ +#define ERROR_BREAK(code) CERROR_BREAK(error, code) + +/* Set error var to the error code, and return it.*/ +#define CERROR_RETURN_ERROR(errorvar, code){\ + errorvar = code;\ + return code;\ +} + +/* Try the code, if it returns error, also return the error. */ +#define CERROR_TRY_RETURN(call){\ + unsigned error = call;\ + if(error) return error;\ +} + +/* Set error var to the error code, and return from the void function. */ +#define CERROR_RETURN(errorvar, code){\ + errorvar = code;\ + return;\ +} + + +/* dynamic vector of unsigned chars */ +struct ucvector +{ + unsigned char* data; + size_t size; /*used size*/ + size_t allocsize; /*allocated size*/ +}; + + +/* returns 1 if success, 0 if failure ==> nothing done */ +static unsigned ucvector_resize(ucvector* p, size_t size) +{ + if (size > p->allocsize) { + size_t newsize = size + (p->allocsize >> 1u); + void* data = realloc(p->data, newsize); + if(data) { + p->allocsize = newsize; + p->data = (unsigned char*)data; + } + else return 0; /*error: not enough memory*/ + } + p->size = size; + return 1; /*success*/ +} + + +static ucvector ucvector_init(unsigned char* buffer, size_t size) +{ + ucvector v; + v.data = buffer; + v.allocsize = v.size = size; + return v; +} + + +static unsigned lodepng_read32bitInt(const unsigned char* buffer) +{ + return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) | ((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]); +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // End of common code and tools. Begin of Zlib related code. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + +struct LodePNGBitReader +{ + const unsigned char* data; + size_t size; /*size of data in bytes*/ + size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/ + size_t bp; + unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/ +}; + + +/* data size argument is in bytes. Returns error if size too large causing overflow */ +static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, const unsigned char* data, size_t size) +{ + size_t temp; + reader->data = data; + reader->size = size; + /* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB) */ + if (lodepng_mulofl(size, 8u, &reader->bitsize)) return 105; + /*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and + trying to ensure 32 more bits*/ + if (lodepng_addofl(reader->bitsize, 64u, &temp)) return 105; + reader->bp = 0; + reader->buffer = 0; + return 0; /*ok*/ + } + +/* + ensureBits functions: + Ensures the reader can at least read nbits bits in one or more readBits calls, + safely even if not enough bits are available. + Returns 1 if there are enough bits available, 0 if not. +*/ + +/*See ensureBits documentation above. This one ensures exactly 1 bit */ +/*static unsigned ensureBits1(LodePNGBitReader* reader) { + if(reader->bp >= reader->bitsize) return 0; + reader->buffer = (unsigned)reader->data[reader->bp >> 3u] >> (reader->bp & 7u); + return 1; +}*/ + +/*See ensureBits documentation above. This one ensures up to 9 bits */ +static unsigned ensureBits9(LodePNGBitReader* reader, size_t nbits) +{ + size_t start = reader->bp >> 3u; + size_t size = reader->size; + if (start + 1u < size) { + reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u); + reader->buffer >>= (reader->bp & 7u); + return 1; + } else { + reader->buffer = 0; + if (start + 0u < size) reader->buffer |= reader->data[start + 0]; + reader->buffer >>= (reader->bp & 7u); + return reader->bp + nbits <= reader->bitsize; + } +} + + +/*See ensureBits documentation above. This one ensures up to 17 bits */ +static unsigned ensureBits17(LodePNGBitReader* reader, size_t nbits) +{ + size_t start = reader->bp >> 3u; + size_t size = reader->size; + if (start + 2u < size) { + reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u); + reader->buffer >>= (reader->bp & 7u); + return 1; + } else { + reader->buffer = 0; + if (start + 0u < size) reader->buffer |= reader->data[start + 0]; + if (start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); + reader->buffer >>= (reader->bp & 7u); + return reader->bp + nbits <= reader->bitsize; + } +} + + +/*See ensureBits documentation above. This one ensures up to 25 bits */ +static LODEPNG_INLINE unsigned ensureBits25(LodePNGBitReader* reader, size_t nbits) +{ + size_t start = reader->bp >> 3u; + size_t size = reader->size; + if (start + 3u < size) { + reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); + reader->buffer >>= (reader->bp & 7u); + return 1; + } else { + reader->buffer = 0; + if (start + 0u < size) reader->buffer |= reader->data[start + 0]; + if (start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); + if (start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); + reader->buffer >>= (reader->bp & 7u); + return reader->bp + nbits <= reader->bitsize; + } +} + + +/*See ensureBits documentation above. This one ensures up to 32 bits */ +static LODEPNG_INLINE unsigned ensureBits32(LodePNGBitReader* reader, size_t nbits) +{ + size_t start = reader->bp >> 3u; + size_t size = reader->size; + if(start + 4u < size) { + reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); + reader->buffer >>= (reader->bp & 7u); + reader->buffer |= (((unsigned)reader->data[start + 4] << 24u) << (8u - (reader->bp & 7u))); + return 1; + } else { + reader->buffer = 0; + if (start + 0u < size) reader->buffer |= reader->data[start + 0]; + if (start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); + if (start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); + if (start + 3u < size) reader->buffer |= ((unsigned)reader->data[start + 3] << 24u); + reader->buffer >>= (reader->bp & 7u); + return reader->bp + nbits <= reader->bitsize; + } +} + + +/* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */ +static unsigned peekBits(LodePNGBitReader* reader, size_t nbits) +{ + /* The shift allows nbits to be only up to 31. */ + return reader->buffer & ((1u << nbits) - 1u); +} + + +/* Must have enough bits available with ensureBits */ +static void advanceBits(LodePNGBitReader* reader, size_t nbits) +{ + reader->buffer >>= nbits; + reader->bp += nbits; +} + + +/* Must have enough bits available with ensureBits */ +static unsigned readBits(LodePNGBitReader* reader, size_t nbits) +{ + unsigned result = peekBits(reader, nbits); + advanceBits(reader, nbits); + return result; +} + + +/* Public for testing only. steps and result must have numsteps values. */ +unsigned lode_png_test_bitreader(const unsigned char* data, size_t size, size_t numsteps, const size_t* steps, unsigned* result) +{ + size_t i; + LodePNGBitReader reader; + unsigned error = LodePNGBitReader_init(&reader, data, size); + if (error) return 0; + for (i = 0; i < numsteps; i++) { + size_t step = steps[i]; + unsigned ok; + if (step > 25) ok = ensureBits32(&reader, step); + else if (step > 17) ok = ensureBits25(&reader, step); + else if (step > 9) ok = ensureBits17(&reader, step); + else ok = ensureBits9(&reader, step); + if (!ok) return 0; + result[i] = readBits(&reader, step); + } + return 1; +} + + +static unsigned reverseBits(unsigned bits, unsigned num) +{ + /*TODO: implement faster lookup table based version when needed*/ + unsigned i, result = 0; + for (i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i; + return result; +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Deflate - Huffman / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +#define FIRST_LENGTH_CODE_INDEX 257 +#define LAST_LENGTH_CODE_INDEX 285 +/*256 literals, the end code, some length codes, and 2 unused codes*/ +#define NUM_DEFLATE_CODE_SYMBOLS 288 +/*the distance codes have their own symbols, 30 used, 2 unused*/ +#define NUM_DISTANCE_SYMBOLS 32 +/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/ +#define NUM_CODE_LENGTH_CODES 19 + +/*the base lengths represented by codes 257-285*/ +static const unsigned LENGTHBASE[29] + = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, + 67, 83, 99, 115, 131, 163, 195, 227, 258}; + +/*the extra bits used by codes 257-285 (added to base length)*/ +static const unsigned LENGTHEXTRA[29] + = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, + 4, 4, 4, 4, 5, 5, 5, 5, 0}; + +/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/ +static const unsigned DISTANCEBASE[30] + = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, + 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577}; + +/*the extra bits of backwards distances (added to base)*/ +static const unsigned DISTANCEEXTRA[30] + = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, + 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13}; + +/*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman +tree of the dynamic huffman tree lengths is generated*/ +static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES] + = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; + +/* ////////////////////////////////////////////////////////////////////////// */ + +/* +Huffman tree struct, containing multiple representations of the tree +*/ +struct HuffmanTree +{ + unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/ + unsigned* lengths; /*the lengths of the huffman codes*/ + unsigned maxbitlen; /*maximum number of bits a single code can get*/ + unsigned numcodes; /*number of symbols in the alphabet = number of codes*/ + /* for reading only */ + unsigned char* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/ + unsigned short* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/ +}; + + +static void HuffmanTree_init(HuffmanTree* tree) +{ + tree->codes = 0; + tree->lengths = 0; + tree->table_len = 0; + tree->table_value = 0; +} + + +static void HuffmanTree_cleanup(HuffmanTree* tree) +{ + free(tree->codes); + free(tree->lengths); + free(tree->table_len); + free(tree->table_value); +} + + +/* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/ +/* values 8u and 9u work the fastest */ +#define FIRSTBITS 9u + +/* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination, +which is possible in case of only 0 or 1 present symbols. */ +#define INVALIDSYMBOL 65535u + +/* make table for huffman decoding */ +static unsigned HuffmanTree_makeTable(HuffmanTree* tree) +{ + static const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/ + static const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u; + size_t i, numpresent, pointer, size; /*total table size*/ + unsigned* maxlens = (unsigned*)malloc(headsize * sizeof(unsigned)); + if (!maxlens) return 83; /*alloc fail*/ + + /* compute maxlens: max total bit length of symbols sharing prefix in the first table*/ + lodepng_memset(maxlens, 0, headsize * sizeof(*maxlens)); + for (i = 0; i < tree->numcodes; i++) { + unsigned symbol = tree->codes[i]; + unsigned l = tree->lengths[i]; + unsigned index; + if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/ + /*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/ + index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS); + maxlens[index] = LODEPNG_MAX(maxlens[index], l); + } + /* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */ + size = headsize; + for (i = 0; i < headsize; ++i) { + unsigned l = maxlens[i]; + if (l > FIRSTBITS) size += (1u << (l - FIRSTBITS)); + } + tree->table_len = (unsigned char*)malloc(size * sizeof(*tree->table_len)); + tree->table_value = (unsigned short*)malloc(size * sizeof(*tree->table_value)); + if (!tree->table_len || !tree->table_value) { + free(maxlens); + /* freeing tree->table values is done at a higher scope */ + return 83; /*alloc fail*/ + } + /*initialize with an invalid length to indicate unused entries*/ + for (i = 0; i < size; ++i) tree->table_len[i] = 16; + + /*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/ + pointer = headsize; + for (i = 0; i < headsize; ++i) { + unsigned l = maxlens[i]; + if(l <= FIRSTBITS) continue; + tree->table_len[i] = l; + tree->table_value[i] = pointer; + pointer += (1u << (l - FIRSTBITS)); + } + free(maxlens); + + /*fill in the first table for short symbols, or secondary table for long symbols*/ + numpresent = 0; + for (i = 0; i < tree->numcodes; ++i) { + unsigned l = tree->lengths[i]; + unsigned symbol = tree->codes[i]; /*the huffman bit pattern. i itself is the value.*/ + /*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/ + unsigned reverse = reverseBits(symbol, l); + if (l == 0) continue; + numpresent++; + + if (l <= FIRSTBITS) { + /*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/ + unsigned num = 1u << (FIRSTBITS - l); + unsigned j; + for (j = 0; j < num; ++j) { + /*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/ + unsigned index = reverse | (j << l); + if(tree->table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ + tree->table_len[index] = l; + tree->table_value[index] = i; + } + } else { + /*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/ + /*the FIRSTBITS MSBs of the symbol are the first table index*/ + unsigned index = reverse & mask; + unsigned maxlen = tree->table_len[index]; + /*log2 of secondary table length, should be >= l - FIRSTBITS*/ + unsigned tablelen = maxlen - FIRSTBITS; + unsigned start = tree->table_value[index]; /*starting index in secondary table*/ + unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/ + unsigned j; + if (maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ + for (j = 0; j < num; ++j) { + unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */ + unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS))); + tree->table_len[index2] = l; + tree->table_value[index2] = i; + } + } + } + + if (numpresent < 2) { + /* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits, + but deflate uses 1 bit instead. In case of 0 symbols, no symbols can + appear at all, but such huffman tree could still exist (e.g. if distance + codes are never used). In both cases, not all symbols of the table will be + filled in. Fill them in with an invalid symbol value so returning them from + huffmanDecodeSymbol will cause error. */ + for (i = 0; i < size; ++i) { + if (tree->table_len[i] == 16) { + /* As length, use a value smaller than FIRSTBITS for the head table, + and a value larger than FIRSTBITS for the secondary table, to ensure + valid behavior for advanceBits when reading this symbol. */ + tree->table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1); + tree->table_value[i] = INVALIDSYMBOL; + } + } + } else { + /* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. + If that is not the case (due to too long length codes), the table will not + have been fully used, and this is an error (not all bit combinations can be + decoded): an oversubscribed huffman tree, indicated by error 55. */ + for (i = 0; i < size; ++i) { + if (tree->table_len[i] == 16) return 55; + } + } + return 0; +} + + +/* + Second step for the ...makeFromLengths and ...makeFromFrequencies functions. + numcodes, lengths and maxbitlen must already be filled in correctly. return + value is error. +*/ +static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) +{ + unsigned* blcount; + unsigned* nextcode; + unsigned error = 0; + unsigned bits, n; + + tree->codes = (unsigned*)malloc(tree->numcodes * sizeof(unsigned)); + blcount = (unsigned*)malloc((tree->maxbitlen + 1) * sizeof(unsigned)); + nextcode = (unsigned*)malloc((tree->maxbitlen + 1) * sizeof(unsigned)); + if (!tree->codes || !blcount || !nextcode) error = 83; /*alloc fail*/ + + if (!error) { + for (n = 0; n != tree->maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0; + /*step 1: count number of instances of each code length*/ + for (bits = 0; bits != tree->numcodes; ++bits) ++blcount[tree->lengths[bits]]; + /*step 2: generate the nextcode values*/ + for(bits = 1; bits <= tree->maxbitlen; ++bits) { + nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u; + } + /*step 3: generate all the codes*/ + for (n = 0; n != tree->numcodes; ++n) { + if (tree->lengths[n] != 0) { + tree->codes[n] = nextcode[tree->lengths[n]]++; + /*remove superfluous bits from the code*/ + tree->codes[n] &= ((1u << tree->lengths[n]) - 1u); + } + } + } + + free(blcount); + free(nextcode); + + if (!error) error = HuffmanTree_makeTable(tree); + return error; +} + + +/* + given the code lengths (as stored in the PNG file), generate the tree as defined + by Deflate. maxbitlen is the maximum bits that a code in the tree can have. + return value is error. +*/ +static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen, size_t numcodes, unsigned maxbitlen) +{ + unsigned i; + tree->lengths = (unsigned*)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); +} + + +/*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*)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); + + 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*)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); + + free(bitlen); + return error; +} + + +/* + returns the code. The bit reader must already have been ensured at least 15 bits +*/ +static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, const HuffmanTree* codetree) +{ + unsigned short code = peekBits(reader, FIRSTBITS); + unsigned short l = codetree->table_len[code]; + unsigned short value = codetree->table_value[code]; + if (l <= FIRSTBITS) { + advanceBits(reader, l); + return value; + } else { + unsigned index2; + advanceBits(reader, FIRSTBITS); + index2 = value + peekBits(reader, l - FIRSTBITS); + advanceBits(reader, codetree->table_len[index2] - FIRSTBITS); + return codetree->table_value[index2]; + } +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Inflator (Decompressor) / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/*get the tree of a deflated block with fixed tree, as specified in the deflate specification +Returns error code.*/ +static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) +{ + unsigned error = generateFixedLitLenTree(tree_ll); + if (error) return error; + return generateFixedDistanceTree(tree_d); +} + + +/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/ +static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d, LodePNGBitReader* reader) +{ + /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/ + unsigned error = 0; + unsigned n, HLIT, HDIST, HCLEN, i; + + /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/ + unsigned* bitlen_ll = 0; /*lit,len code lengths*/ + unsigned* bitlen_d = 0; /*dist code lengths*/ + /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/ + unsigned* bitlen_cl = 0; + HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/ + + if (!ensureBits17(reader, 14)) 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 = readBits(reader, 5) + 257; + /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/ + HDIST = readBits(reader, 5) + 1; + /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/ + HCLEN = readBits(reader, 4) + 4; + + bitlen_cl = (unsigned*)malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned)); + if(!bitlen_cl) return 83 /*alloc fail*/; + + HuffmanTree_init(&tree_cl); + + while (!error) { + /*read the code length codes out of 3 * (amount of code length codes) bits*/ + if (lodepng_gtofl(reader->bp, HCLEN * 3, reader->bitsize)) { + ERROR_BREAK(50); /*error: the bit pointer is or will go past the memory*/ + } + for (i = 0; i != HCLEN; ++i) { + ensureBits9(reader, 3); /*out of bounds already checked above */ + bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3); + } + for (i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) { + bitlen_cl[CLCL_ORDER[i]] = 0; + } + + error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7); + if(error) break; + + /*now we can use this tree to read the lengths for the tree that this function will return*/ + bitlen_ll = (unsigned*)malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); + bitlen_d = (unsigned*)malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); + if (!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); + lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(*bitlen_ll)); + lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(*bitlen_d)); + + /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/ + i = 0; + while (i < HLIT + HDIST) { + unsigned code; + ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/ + code = huffmanDecodeSymbol(reader, &tree_cl); + if (code <= 15) /*a length code*/ { + if (i < HLIT) bitlen_ll[i] = code; + else bitlen_d[i - HLIT] = code; + ++i; + } else if (code == 16) /*repeat previous*/ { + unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/ + unsigned value; /*set value to the previous code*/ + + if (i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ + + replength += readBits(reader, 2); + + if (i < HLIT + 1) value = bitlen_ll[i - 1]; + else value = bitlen_d[i - HLIT - 1]; + /*repeat this value in the next lengths*/ + for (n = 0; n < replength; ++n) { + if (i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/ + if (i < HLIT) bitlen_ll[i] = value; + else bitlen_d[i - HLIT] = value; + ++i; + } + } else if(code == 17) /*repeat "0" 3-10 times*/ { + unsigned replength = 3; /*read in the bits that indicate repeat length*/ + replength += readBits(reader, 3); + + /*repeat this value in the next lengths*/ + for (n = 0; n < replength; ++n) { + if (i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/ + + if (i < HLIT) bitlen_ll[i] = 0; + else bitlen_d[i - HLIT] = 0; + ++i; + } + } else if(code == 18) /*repeat "0" 11-138 times*/ { + unsigned replength = 11; /*read in the bits that indicate repeat length*/ + replength += readBits(reader, 7); + + /*repeat this value in the next lengths*/ + for (n = 0; n < replength; ++n) { + if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/ + + if(i < HLIT) bitlen_ll[i] = 0; + else bitlen_d[i - HLIT] = 0; + ++i; + } + } else /*if(code == INVALIDSYMBOL)*/ { + ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ + } + /*check if any of the ensureBits above went out of bounds*/ + if (reader->bp > reader->bitsize) { + /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol + (10=no endcode, 11=wrong jump outside of tree)*/ + /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ + ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ + } + } + if (error) break; + + if (bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/ + + /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/ + error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15); + if (error) break; + error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15); + + break; /*end of error-while*/ + } + + free(bitlen_cl); + free(bitlen_ll); + free(bitlen_d); + HuffmanTree_cleanup(&tree_cl); + + return error; +} + + +/*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/ +static unsigned inflateHuffmanBlock(ucvector* out, LodePNGBitReader* reader, unsigned btype) +{ + unsigned error = 0; + HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/ + HuffmanTree tree_d; /*the huffman tree for distance codes*/ + + HuffmanTree_init(&tree_ll); + HuffmanTree_init(&tree_d); + + if (btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d); + else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader); + + while (!error) /*decode all symbols until end reached, breaks at end code*/ { + /*code_ll is literal, length or end code*/ + unsigned code_ll; + ensureBits25(reader, 20); /* up to 15 for the huffman symbol, up to 5 for the length extra bits */ + code_ll = huffmanDecodeSymbol(reader, &tree_ll); + if (code_ll <= 255) /*literal symbol*/ { + if (!ucvector_resize(out, out->size + 1)) ERROR_BREAK(83 /*alloc fail*/); + out->data[out->size - 1] = (unsigned char)code_ll; + } else if (code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ { + unsigned code_d, distance; + unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/ + size_t start, backward, length; + + /*part 1: get length base*/ + length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX]; + + /*part 2: get extra bits and add the value of that to length*/ + numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX]; + if (numextrabits_l != 0) { + /* bits already ensured above */ + length += readBits(reader, numextrabits_l); + } + + /*part 3: get distance code*/ + ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */ + code_d = huffmanDecodeSymbol(reader, &tree_d); + if (code_d > 29) { + if (code_d <= 31) { + ERROR_BREAK(18); /*error: invalid distance code (30-31 are never used)*/ + } else /* if(code_d == INVALIDSYMBOL) */{ + ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ + } + } + distance = DISTANCEBASE[code_d]; + + /*part 4: get extra bits from distance*/ + numextrabits_d = DISTANCEEXTRA[code_d]; + if (numextrabits_d != 0) { + /* bits already ensured above */ + distance += readBits(reader, numextrabits_d); + } + + /*part 5: fill in all the out[n] values based on the length and dist*/ + start = out->size; + if (distance > start) ERROR_BREAK(52); /*too long backward distance*/ + backward = start - distance; + + if (!ucvector_resize(out, out->size + length)) ERROR_BREAK(83 /*alloc fail*/); + if (distance < length) { + size_t forward; + lodepng_memcpy(out->data + start, out->data + backward, distance); + start += distance; + for (forward = distance; forward < length; ++forward) { + out->data[start++] = out->data[backward++]; + } + } else { + lodepng_memcpy(out->data + start, out->data + backward, length); + } + } else if (code_ll == 256) { + break; /*end code, break the loop*/ + } else /*if(code_ll == INVALIDSYMBOL)*/ { + ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ + } + /*check if any of the ensureBits above went out of bounds*/ + if (reader->bp > reader->bitsize) { + /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol + (10=no endcode, 11=wrong jump outside of tree)*/ + /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ + ERROR_BREAK(51); /*error, bit pointer jumps past memory*/ + } + } + + HuffmanTree_cleanup(&tree_ll); + HuffmanTree_cleanup(&tree_d); + + return error; +} + + +static unsigned inflateNoCompression(ucvector* out, LodePNGBitReader* reader, const LodePNGDecompressSettings* settings) +{ + size_t bytepos; + size_t size = reader->size; + unsigned LEN, NLEN, error = 0; + + /*go to first boundary of byte*/ + bytepos = (reader->bp + 7u) >> 3u; + + /*read LEN (2 bytes) and NLEN (2 bytes)*/ + if (bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/ + LEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; + NLEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; + + /*check if 16-bit NLEN is really the one's complement of LEN*/ + if (!settings->ignore_nlen && LEN + NLEN != 65535) { + return 21; /*error: NLEN is not one's complement of LEN*/ + } + + if (!ucvector_resize(out, out->size + LEN)) return 83; /*alloc fail*/ + + /*read the literal data: LEN bytes are now stored in the out buffer*/ + if (bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/ + + lodepng_memcpy(out->data + out->size - LEN, reader->data + bytepos, LEN); + bytepos += LEN; + + reader->bp = bytepos << 3u; + + return error; +} + + +static unsigned lodepng_inflatev(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) +{ + unsigned BFINAL = 0; + LodePNGBitReader reader; + unsigned error = LodePNGBitReader_init(&reader, in, insize); + + if (error) return error; + + while (!BFINAL) { + unsigned BTYPE; + if (!ensureBits9(&reader, 3)) return 52; /*error, bit pointer will jump past memory*/ + BFINAL = readBits(&reader, 1); + BTYPE = readBits(&reader, 2); + + if (BTYPE == 3) return 20; /*error: invalid BTYPE*/ + else if (BTYPE == 0) error = inflateNoCompression(out, &reader, settings); /*no compression*/ + else error = inflateHuffmanBlock(out, &reader, BTYPE); /*compression, BTYPE 01 or 10*/ + + if (error) return error; + } + + return error; +} + + +static unsigned inflatev(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) +{ + if (settings->custom_inflate) { + unsigned error = settings->custom_inflate(&out->data, &out->size, in, insize, settings); + out->allocsize = out->size; + return error; + } else { + return lodepng_inflatev(out, in, insize, settings); + } +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Adler32 / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) +{ + unsigned s1 = adler & 0xffffu; + unsigned s2 = (adler >> 16u) & 0xffffu; + + while (len != 0u) { + unsigned i; + /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/ + unsigned amount = len > 5552u ? 5552u : len; + len -= amount; + for (i = 0; i != amount; ++i) { + s1 += (*data++); + s2 += s1; + } + s1 %= 65521u; + s2 %= 65521u; + } + + return (s2 << 16u) | s1; +} + +/*Return the adler32 of the bytes data[0..len-1]*/ +static unsigned adler32(const unsigned char* data, unsigned len) +{ + return update_adler32(1u, data, len); +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Zlib / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +static unsigned lodepng_zlib_decompressv(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) +{ + unsigned error = 0; + unsigned CM, CINFO, FDICT; + + if (insize < 2) return 53; /*error, size of zlib data too small*/ + /*read information from zlib header*/ + if ((in[0] * 256 + in[1]) % 31 != 0) { + /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/ + return 24; + } + + CM = in[0] & 15; + CINFO = (in[0] >> 4) & 15; + /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/ + FDICT = (in[1] >> 5) & 1; + /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/ + + if (CM != 8 || CINFO > 7) { + /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/ + return 25; + } + if (FDICT != 0) { + /*error: the specification of PNG says about the zlib stream: + "The additional flags shall not specify a preset dictionary."*/ + return 26; + } + + error = inflatev(out, in + 2, insize - 2, settings); + if (error) return error; + + if (!settings->ignore_adler32) { + unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]); + unsigned checksum = adler32(out->data, (unsigned)(out->size)); + if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/ + } + + return 0; /*no error*/ +} + + +/*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */ +static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) +{ + if(settings->custom_zlib) { + return settings->custom_zlib(out, outsize, in, insize, settings); + } else { + unsigned error; + ucvector v = ucvector_init(*out, *outsize); + if (expected_size) { + /*reserve the memory to avoid intermediate reallocations*/ + ucvector_resize(&v, *outsize + expected_size); + v.size = *outsize; + } + error = lodepng_zlib_decompressv(&v, in, insize, settings); + *out = v.data; + *outsize = v.size; + return error; + } +} + + +static void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) +{ + settings->ignore_adler32 = 0; + settings->ignore_nlen = 0; + settings->custom_zlib = 0; + settings->custom_inflate = 0; + settings->custom_context = 0; +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* // End of Zlib related code. Begin of PNG related code. // */ +/* ////////////////////////////////////////////////////////////////////////// */ +/* ////////////////////////////////////////////////////////////////////////// */ + + +#if 0 //thorvg don't use 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 +}; + + +/* Calculate CRC32 of buffer + Return the CRC of the bytes buf[0..len-1]. */ +static 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]) & 0xffu] ^ (r >> 8u); + } + return r ^ 0xffffffffu; +} +#endif + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Reading and writing PNG color channel bits / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first, +so LodePNGBitWriter and LodePNGBitReader can't be used for those. */ + +static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) +{ + unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1); + ++(*bitpointer); + return result; +} + + +/* TODO: make this faster */ +static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) +{ + unsigned result = 0; + size_t i; + for (i = 0 ; i < nbits; ++i) { + result <<= 1u; + result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream); + } + return result; +} + + +static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) +{ + /*the current bit in bitstream may be 0 or 1 for this to work*/ + if (bit == 0) bitstream[(*bitpointer) >> 3u] &= (unsigned char)(~(1u << (7u - ((*bitpointer) & 7u)))); + else bitstream[(*bitpointer) >> 3u] |= (1u << (7u - ((*bitpointer) & 7u))); + ++(*bitpointer); +} + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / PNG chunks / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/* + The lodepng_chunk functions are normally not needed, except to traverse the + unknown chunks stored in the LodePNGInfo struct, or add new ones to it. + It also allows traversing the chunks of an encoded PNG file yourself. + + The chunk pointer always points to the beginning of the chunk itself, that is + the first byte of the 4 length bytes. + + In the PNG file format, chunks have the following format: + -4 bytes length: length of the data of the chunk in bytes (chunk itself is 12 bytes longer) + -4 bytes chunk type (ASCII a-z,A-Z only, see below) + -length bytes of data (may be 0 bytes if length was 0) + -4 bytes of CRC, computed on chunk name + data + + The first chunk starts at the 8th byte of the PNG file, the entire rest of the file + exists out of concatenated chunks with the above format. + + PNG standard chunk ASCII naming conventions: + -First byte: uppercase = critical, lowercase = ancillary + -Second byte: uppercase = public, lowercase = private + -Third byte: must be uppercase + -Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy +*/ + + +/* + Gets the length of the data of the chunk. Total chunk length has 12 bytes more. + There must be at least 4 bytes to read from. If the result value is too large, + it may be corrupt data. +*/ +static unsigned lodepng_chunk_length(const unsigned char* chunk) +{ + return lodepng_read32bitInt(&chunk[0]); +} + + +/* check if the type is the given type */ +static unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) +{ + if (lodepng_strlen(type) != 4) return 0; + return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]); +} + + +/* 0: it's one of the critical chunk types, 1: it's an ancillary chunk (see PNG standard) */ +static unsigned char lodepng_chunk_ancillary(const unsigned char* chunk) +{ + return ((chunk[4] & 32) != 0); +} + + +static const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk) +{ + return &chunk[8]; +} + +#if 0 //thorvg don't use crc +/* returns 0 if the crc is correct, 1 if it's incorrect (0 for OK as usual!) */ +static 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; +} +#endif + +static const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end) +{ + if (chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/ + if (chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 + && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { + /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ + return chunk + 8; + } else { + size_t total_chunk_length; + const unsigned char* result; + if (lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end; + result = chunk + total_chunk_length; + if (result < chunk) return end; /*pointer overflow*/ + return result; + } +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / Color types, channels, bits / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype. +Return value is a LodePNG error code.*/ +static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) +{ + switch(colortype) { + case LCT_GREY: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; + case LCT_RGB: if(!( bd == 8 || bd == 16)) return 37; break; + case LCT_PALETTE: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break; + case LCT_GREY_ALPHA: if(!( bd == 8 || bd == 16)) return 37; break; + case LCT_RGBA: if(!( bd == 8 || bd == 16)) return 37; break; + case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */ + default: return 31; /* invalid color type */ + } + return 0; /*allowed color type / bits combination*/ +} + + +static unsigned getNumColorChannels(LodePNGColorType colortype) +{ + switch(colortype) { + case LCT_GREY: return 1; + case LCT_RGB: return 3; + case LCT_PALETTE: return 1; + case LCT_GREY_ALPHA: return 2; + case LCT_RGBA: return 4; + case LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */ + default: return 0; /*invalid color type*/ + } +} + + +static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) +{ + /*bits per pixel is amount of channels * bits per channel*/ + return getNumColorChannels(colortype) * bitdepth; +} + + +static void lodepng_color_mode_init(LodePNGColorMode* info) +{ + info->key_defined = 0; + info->key_r = info->key_g = info->key_b = 0; + info->colortype = LCT_RGBA; + info->bitdepth = 8; + info->palette = 0; + info->palettesize = 0; +} + + +/*allocates palette memory if needed, and initializes all colors to black*/ +static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) +{ + size_t i; + /*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/ + /*the palette must have room for up to 256 colors with 4 bytes each.*/ + if (!info->palette) info->palette = (unsigned char*)malloc(1024); + if (!info->palette) return; /*alloc fail*/ + for (i = 0; i != 256; ++i) { + /*Initialize all unused colors with black, the value used for invalid palette indices. + This is an error according to the PNG spec, but common PNG decoders make it black instead. + That makes color conversion slightly faster due to no error handling needed.*/ + info->palette[i * 4 + 0] = 0; + info->palette[i * 4 + 1] = 0; + info->palette[i * 4 + 2] = 0; + info->palette[i * 4 + 3] = 255; + } +} + +static void lodepng_palette_clear(LodePNGColorMode* info) +{ + if (info->palette) free(info->palette); + info->palette = 0; + info->palettesize = 0; +} + + +static void lodepng_color_mode_cleanup(LodePNGColorMode* info) +{ + lodepng_palette_clear(info); +} + + +/*return value is error code (0 means no error)*/ +static unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) +{ + lodepng_color_mode_cleanup(dest); + lodepng_memcpy(dest, source, sizeof(LodePNGColorMode)); + if (source->palette) { + dest->palette = (unsigned char*)malloc(1024); + if (!dest->palette && source->palettesize) return 83; /*alloc fail*/ + lodepng_memcpy(dest->palette, source->palette, source->palettesize * 4); + } + return 0; +} + + +static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) +{ + size_t i; + if (a->colortype != b->colortype) return 0; + if (a->bitdepth != b->bitdepth) return 0; + if (a->key_defined != b->key_defined) return 0; + if (a->key_defined) { + if(a->key_r != b->key_r) return 0; + if(a->key_g != b->key_g) return 0; + if(a->key_b != b->key_b) return 0; + } + if (a->palettesize != b->palettesize) return 0; + for (i = 0; i != a->palettesize * 4; ++i) { + if (a->palette[i] != b->palette[i]) return 0; + } + return 1; +} + + +static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) +{ + size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth); + size_t n = (size_t)w * (size_t)h; + return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u; +} + + +/* Returns the byte size of a raw image buffer with given width, height and color mode */ +static 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); +} + + +/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer, +and in addition has one extra byte per line: the filter byte. So this gives a larger +result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */ +static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) +{ + /* + 1 for the filter byte, and possibly plus padding bits per line. */ + /* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */ + size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u; + return (size_t)h * line; +} + + +/* 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_lct(pngcolor->colortype, pngcolor->bitdepth), lodepng_get_bpp_lct(rawcolor->colortype, rawcolor->bitdepth)); + size_t numpixels, total; + size_t line; /* bytes per line in worst case */ + + if (lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1; + if (lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */ + + /* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */ + if (lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return 1; + if (lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return 1; + + if (lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */ + if (lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */ + + return 0; /* no overflow */ +} + + +static void lodepng_info_init(LodePNGInfo* info) +{ + lodepng_color_mode_init(&info->color); + info->interlace_method = 0; + info->compression_method = 0; + info->filter_method = 0; +} + + +static void lodepng_info_cleanup(LodePNGInfo* info) +{ + lodepng_color_mode_cleanup(&info->color); +} + + +/* index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to */ +static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) +{ + unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/ + /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/ + unsigned p = index & m; + in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/ + in = in << (bits * (m - p)); + if(p == 0) out[index * bits / 8u] = in; + else out[index * bits / 8u] |= in; +} + +/* + One node of a color tree + This is the data structure used to count the number of unique colors and to get a palette + index for a color. It's like an octree, but because the alpha channel is used too, each + node has 16 instead of 8 children. +*/ +struct ColorTree +{ + ColorTree* children[16]; /* up to 16 pointers to ColorTree of next level */ + int index; /* the payload. Only has a meaningful value if this is in the last level */ +}; + +static void color_tree_init(ColorTree* tree) +{ + lodepng_memset(tree->children, 0, 16 * sizeof(*tree->children)); + tree->index = -1; +} + +static void color_tree_cleanup(ColorTree* tree) +{ + int i; + for (i = 0; i != 16; ++i) { + if(tree->children[i]) { + color_tree_cleanup(tree->children[i]); + 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; +} + + +/* color is not allowed to already exist. + Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist") + Returns error code, or 0 if ok */ +static unsigned color_tree_add(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) +{ + int bit; + for (bit = 0; bit < 8; ++bit) { + int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); + if (!tree->children[i]) { + tree->children[i] = (ColorTree*)malloc(sizeof(ColorTree)); + if (!tree->children[i]) return 83; /*alloc fail*/ + color_tree_init(tree->children[i]); + } + tree = tree->children[i]; + } + tree->index = (int)index; + return 0; +} + +/* put a pixel, given its RGBA color, into image of any color type */ +static unsigned rgba8ToPixel(unsigned char* out, size_t i, const LodePNGColorMode* mode, ColorTree* tree /*for palette*/, unsigned char r, unsigned char g, unsigned char b, unsigned char a) +{ + if (mode->colortype == LCT_GREY) { + unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ + if (mode->bitdepth == 8) out[i] = gray; + else if (mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray; + else { + /*take the most significant bits of gray*/ + gray = ((unsigned)gray >> (8u - mode->bitdepth)) & ((1u << mode->bitdepth) - 1u); + addColorBits(out, i, mode->bitdepth, gray); + } + } else if (mode->colortype == LCT_RGB) { + if (mode->bitdepth == 8) { + out[i * 3 + 0] = r; + out[i * 3 + 1] = g; + out[i * 3 + 2] = b; + } else { + out[i * 6 + 0] = out[i * 6 + 1] = r; + out[i * 6 + 2] = out[i * 6 + 3] = g; + out[i * 6 + 4] = out[i * 6 + 5] = b; + } + } else if(mode->colortype == LCT_PALETTE) { + int index = color_tree_get(tree, r, g, b, a); + if (index < 0) return 82; /*color not in palette*/ + if (mode->bitdepth == 8) out[i] = index; + else addColorBits(out, i, mode->bitdepth, (unsigned)index); + } else if (mode->colortype == LCT_GREY_ALPHA) { + unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ + if (mode->bitdepth == 8) { + out[i * 2 + 0] = gray; + out[i * 2 + 1] = a; + } else if (mode->bitdepth == 16) { + out[i * 4 + 0] = out[i * 4 + 1] = gray; + out[i * 4 + 2] = out[i * 4 + 3] = a; + } + } else if (mode->colortype == LCT_RGBA) { + if (mode->bitdepth == 8) { + out[i * 4 + 0] = r; + out[i * 4 + 1] = g; + out[i * 4 + 2] = b; + out[i * 4 + 3] = a; + } else { + out[i * 8 + 0] = out[i * 8 + 1] = r; + out[i * 8 + 2] = out[i * 8 + 3] = g; + out[i * 8 + 4] = out[i * 8 + 5] = b; + out[i * 8 + 6] = out[i * 8 + 7] = a; + } + } + return 0; /*no error*/ +} + + +/* put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type */ +static void rgba16ToPixel(unsigned char* out, size_t i, const LodePNGColorMode* mode, unsigned short r, unsigned short g, unsigned short b, unsigned short a) +{ + if (mode->colortype == LCT_GREY) { + unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ + out[i * 2 + 0] = (gray >> 8) & 255; + out[i * 2 + 1] = gray & 255; + } else if (mode->colortype == LCT_RGB) { + out[i * 6 + 0] = (r >> 8) & 255; + out[i * 6 + 1] = r & 255; + out[i * 6 + 2] = (g >> 8) & 255; + out[i * 6 + 3] = g & 255; + out[i * 6 + 4] = (b >> 8) & 255; + out[i * 6 + 5] = b & 255; + } else if (mode->colortype == LCT_GREY_ALPHA) { + unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ + out[i * 4 + 0] = (gray >> 8) & 255; + out[i * 4 + 1] = gray & 255; + out[i * 4 + 2] = (a >> 8) & 255; + out[i * 4 + 3] = a & 255; + } else if (mode->colortype == LCT_RGBA) { + out[i * 8 + 0] = (r >> 8) & 255; + out[i * 8 + 1] = r & 255; + out[i * 8 + 2] = (g >> 8) & 255; + out[i * 8 + 3] = g & 255; + out[i * 8 + 4] = (b >> 8) & 255; + out[i * 8 + 5] = b & 255; + out[i * 8 + 6] = (a >> 8) & 255; + out[i * 8 + 7] = a & 255; + } +} + + +/* Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type. */ +static void getPixelColorRGBA8(unsigned char* r, unsigned char* g, unsigned char* b, unsigned char* a, const unsigned char* in, size_t i, const LodePNGColorMode* mode) +{ + if (mode->colortype == LCT_GREY) { + if (mode->bitdepth == 8) { + *r = *g = *b = in[i]; + if (mode->key_defined && *r == mode->key_r) *a = 0; + else *a = 255; + } else if (mode->bitdepth == 16) { + *r = *g = *b = in[i * 2 + 0]; + if (mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; + else *a = 255; + } else { + unsigned highest = ((1U << mode->bitdepth) - 1U); /* highest possible value for this bit depth */ + size_t j = i * mode->bitdepth; + unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); + *r = *g = *b = (value * 255) / highest; + if (mode->key_defined && value == mode->key_r) *a = 0; + else *a = 255; + } + } else if (mode->colortype == LCT_RGB) { + if (mode->bitdepth == 8) { + *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2]; + if (mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0; + else *a = 255; + } else { + *r = in[i * 6 + 0]; + *g = in[i * 6 + 2]; + *b = in[i * 6 + 4]; + if (mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; + else *a = 255; + } + } else if (mode->colortype == LCT_PALETTE) { + unsigned index; + if (mode->bitdepth == 8) index = in[i]; + else { + size_t j = i * mode->bitdepth; + index = readBitsFromReversedStream(&j, in, mode->bitdepth); + } + /* out of bounds of palette not checked: see lodepng_color_mode_alloc_palette. */ + *r = mode->palette[index * 4 + 0]; + *g = mode->palette[index * 4 + 1]; + *b = mode->palette[index * 4 + 2]; + *a = mode->palette[index * 4 + 3]; + } else if (mode->colortype == LCT_GREY_ALPHA) { + if (mode->bitdepth == 8) { + *r = *g = *b = in[i * 2 + 0]; + *a = in[i * 2 + 1]; + } else { + *r = *g = *b = in[i * 4 + 0]; + *a = in[i * 4 + 2]; + } + } else if (mode->colortype == LCT_RGBA) { + if (mode->bitdepth == 8) { + *r = in[i * 4 + 0]; + *g = in[i * 4 + 1]; + *b = in[i * 4 + 2]; + *a = in[i * 4 + 3]; + } else { + *r = in[i * 8 + 0]; + *g = in[i * 8 + 2]; + *b = in[i * 8 + 4]; + *a = in[i * 8 + 6]; + } + } +} + + +/* Similar to getPixelColorRGBA8, but with all the for loops inside of the color + mode test cases, optimized to convert the colors much faster, when converting + to the common case of RGBA with 8 bit per channel. buffer must be RGBA with + enough memory.*/ +static void getPixelColorsRGBA8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, const unsigned char* LODEPNG_RESTRICT in, const LodePNGColorMode* mode) +{ + unsigned num_channels = 4; + size_t i; + if (mode->colortype == LCT_GREY) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i]; + buffer[3] = 255; + } + if (mode->key_defined) { + buffer -= numpixels * num_channels; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + if(buffer[0] == mode->key_r) buffer[3] = 0; + } + } + } else if (mode->bitdepth == 16) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2]; + buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255; + } + } else { + unsigned highest = ((1U << mode->bitdepth) - 1U); /* highest possible value for this bit depth */ + size_t j = 0; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); + buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; + buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255; + } + } + } else if (mode->colortype == LCT_RGB) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + //lodepng_memcpy(buffer, &in[i * 3], 3); + //Convert colortype to LCT_BGR? + buffer[0] = in[i * 3 + 2]; + buffer[1] = in[i * 3 + 1]; + buffer[2] = in[i * 3 + 0]; + buffer[3] = 255; + } + if (mode->key_defined) { + buffer -= numpixels * num_channels; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + if (buffer[0] == mode->key_r && buffer[1]== mode->key_g && buffer[2] == mode->key_b) buffer[3] = 0; + } + } + } else { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 6 + 0]; + buffer[1] = in[i * 6 + 2]; + buffer[2] = in[i * 6 + 4]; + buffer[3] = mode->key_defined + && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255; + } + } + } else if (mode->colortype == LCT_PALETTE) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned index = in[i]; + /* out of bounds of palette not checked: see lodepng_color_mode_alloc_palette. */ + lodepng_memcpy(buffer, &mode->palette[index * 4], 4); + } + } else { + size_t j = 0; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); + /* out of bounds of palette not checked: see lodepng_color_mode_alloc_palette. */ + lodepng_memcpy(buffer, &mode->palette[index * 4], 4); + } + } + } else if (mode->colortype == LCT_GREY_ALPHA) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; + buffer[3] = in[i * 2 + 1]; + } + } else { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; + buffer[3] = in[i * 4 + 2]; + } + } + } else if (mode->colortype == LCT_RGBA) { + if (mode->bitdepth == 8) { + lodepng_memcpy(buffer, in, numpixels * 4); + } else { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 8 + 0]; + buffer[1] = in[i * 8 + 2]; + buffer[2] = in[i * 8 + 4]; + buffer[3] = in[i * 8 + 6]; + } + } + } +} + + +/* Similar to getPixelColorsRGBA8, but with 3-channel RGB output. */ +static void getPixelColorsRGB8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, const unsigned char* LODEPNG_RESTRICT in, const LodePNGColorMode* mode) +{ + const unsigned num_channels = 3; + size_t i; + if (mode->colortype == LCT_GREY) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i]; + } + } else if (mode->bitdepth == 16) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2]; + } + } else { + unsigned highest = ((1U << mode->bitdepth) - 1U); /* highest possible value for this bit depth */ + size_t j = 0; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); + buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; + } + } + } else if (mode->colortype == LCT_RGB) { + if (mode->bitdepth == 8) { + lodepng_memcpy(buffer, in, numpixels * 3); + } else { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 6 + 0]; + buffer[1] = in[i * 6 + 2]; + buffer[2] = in[i * 6 + 4]; + } + } + } else if (mode->colortype == LCT_PALETTE) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned index = in[i]; + /* out of bounds of palette not checked: see lodepng_color_mode_alloc_palette. */ + lodepng_memcpy(buffer, &mode->palette[index * 4], 3); + } + } else { + size_t j = 0; + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); + /* out of bounds of palette not checked: see lodepng_color_mode_alloc_palette. */ + lodepng_memcpy(buffer, &mode->palette[index * 4], 3); + } + } + } else if (mode->colortype == LCT_GREY_ALPHA) { + if (mode->bitdepth == 8) { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; + } + } else { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; + } + } + } else if (mode->colortype == LCT_RGBA) { + if (mode->bitdepth == 8) { + for(i = 0; i != numpixels; ++i, buffer += num_channels) { + lodepng_memcpy(buffer, &in[i * 4], 3); + } + } else { + for (i = 0; i != numpixels; ++i, buffer += num_channels) { + buffer[0] = in[i * 8 + 0]; + buffer[1] = in[i * 8 + 2]; + buffer[2] = in[i * 8 + 4]; + } + } + } +} + + +/* Get RGBA16 color of pixel with index i (y * width + x) from the raw image with + given color type, but the given color type must be 16-bit itself. */ +static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a, const unsigned char* in, size_t i, const LodePNGColorMode* mode) +{ + if (mode->colortype == LCT_GREY) { + *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1]; + if (mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; + else *a = 65535; + } else if (mode->colortype == LCT_RGB) { + *r = 256u * in[i * 6 + 0] + in[i * 6 + 1]; + *g = 256u * in[i * 6 + 2] + in[i * 6 + 3]; + *b = 256u * in[i * 6 + 4] + in[i * 6 + 5]; + if (mode->key_defined + && 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r + && 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g + && 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; + else *a = 65535; + } else if (mode->colortype == LCT_GREY_ALPHA) { + *r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1]; + *a = 256u * in[i * 4 + 2] + in[i * 4 + 3]; + } else if (mode->colortype == LCT_RGBA) { + *r = 256u * in[i * 8 + 0] + in[i * 8 + 1]; + *g = 256u * in[i * 8 + 2] + in[i * 8 + 3]; + *b = 256u * in[i * 8 + 4] + in[i * 8 + 5]; + *a = 256u * in[i * 8 + 6] + in[i * 8 + 7]; + } +} + +/* + Converts raw buffer from one color type to another color type, based on + LodePNGColorMode structs to describe the input and output color type. + See the reference manual at the end of this header file to see which color conversions are supported. + return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported) + The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel + of the output color type (lodepng_get_bpp). + For < 8 bpp images, there should not be padding bits at the end of scanlines. + For 16-bit per channel colors, uses big endian format like PNG does. + Return value is LodePNG error code +*/ +static unsigned lodepng_convert(unsigned char* out, const unsigned char* in, const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, unsigned w, unsigned h) +{ + size_t i; + ColorTree tree; + size_t numpixels = (size_t)w * (size_t)h; + unsigned error = 0; + + if (mode_in->colortype == LCT_PALETTE && !mode_in->palette) { + return 107; /* error: must provide palette if input mode is palette */ + } + + if (lodepng_color_mode_equal(mode_out, mode_in)) { + size_t numbytes = lodepng_get_raw_size(w, h, mode_in); + lodepng_memcpy(out, in, numbytes); + return 0; + } + + if (mode_out->colortype == LCT_PALETTE) { + size_t palettesize = mode_out->palettesize; + const unsigned char* palette = mode_out->palette; + size_t palsize = (size_t)1u << mode_out->bitdepth; + /* if the user specified output palette but did not give the values, assume + they want the values of the input color type (assuming that one is palette). + Note that we never create a new palette ourselves.*/ + if (palettesize == 0) { + palettesize = mode_in->palettesize; + palette = mode_in->palette; + /* if the input was also palette with same bitdepth, then the color types are also + equal, so copy literally. This to preserve the exact indices that were in the PNG + even in case there are duplicate colors in the palette.*/ + if (mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) { + size_t numbytes = lodepng_get_raw_size(w, h, mode_in); + lodepng_memcpy(out, in, numbytes); + return 0; + } + } + if (palettesize < palsize) palsize = palettesize; + color_tree_init(&tree); + for (i = 0; i != palsize; ++i) { + const unsigned char* p = &palette[i * 4]; + error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i); + if (error) break; + } + } + + if (!error) { + if (mode_in->bitdepth == 16 && mode_out->bitdepth == 16) { + for (i = 0; i != numpixels; ++i) { + unsigned short r = 0, g = 0, b = 0, a = 0; + getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); + rgba16ToPixel(out, i, mode_out, r, g, b, a); + } + } else if (mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) { + getPixelColorsRGBA8(out, numpixels, in, mode_in); + } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) { + getPixelColorsRGB8(out, numpixels, in, mode_in); + } else { + unsigned char r = 0, g = 0, b = 0, a = 0; + for (i = 0; i != numpixels; ++i) { + getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); + error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a); + if (error) break; + } + } + } + + if (mode_out->colortype == LCT_PALETTE) { + color_tree_cleanup(&tree); + } + + return error; +} + + +/* Paeth predictor, 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 = LODEPNG_ABS(b - c); + short pb = LODEPNG_ABS(a - c); + short pc = LODEPNG_ABS(a + b - c - c); + /* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */ + if (pb < pa) { a = b; pa = pb; } + return (pc < pa) ? c : a; +} + + +/*shared values used by multiple Adam7 related functions*/ +static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/ +static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/ +static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/ +static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/ + +/* Outputs various dimensions and positions in the image related to the Adam7 reduced images. + passw: output containing the width of the 7 passes + passh: output containing the height of the 7 passes + filter_passstart: output containing the index of the start and end of each + reduced image with filter bytes + padded_passstart output containing the index of the start and end of each + reduced image when without filter bytes but with padded scanlines + passstart: output containing the index of the start and end of each reduced + image without padding between scanlines, but still padding between the images + w, h: width and height of non-interlaced image + bpp: bits per pixel + "padded" is only relevant if bpp is less than 8 and a scanline or image does not + end at a full byte */ +static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8], size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) +{ + /* the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass */ + unsigned i; + + /* calculate width and height in pixels of each pass */ + for (i = 0; i != 7; ++i) { + passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i]; + passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i]; + if(passw[i] == 0) passh[i] = 0; + if(passh[i] == 0) passw[i] = 0; + } + + filter_passstart[0] = padded_passstart[0] = passstart[0] = 0; + for (i = 0; i != 7; ++i) { + /* if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte) */ + filter_passstart[i + 1] = filter_passstart[i] + + ((passw[i] && passh[i]) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0); + /* bits padded if needed to fill full byte at end of each scanline */ + padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u); + /* only padded at end of reduced image */ + passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u; + } +} + + +/* ////////////////////////////////////////////////////////////////////////// */ +/* / PNG Decoder / */ +/* ////////////////////////////////////////////////////////////////////////// */ + +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: { + if (bytewidth == 4) { + for (i = 0; i < length; i += 4) { + //RGBA -> BGRA + recon[i + 0] = scanline[i + 2]; + recon[i + 1] = scanline[i + 1]; + recon[i + 2] = scanline[i + 0]; + recon[i + 3] = scanline[i + 3]; + } + } else { + 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] >> 1u); + for (i = bytewidth; i < length; ++i) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) >> 1u); + } else { + for (i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; + for (i = bytewidth; i < length; ++i) recon[i] = scanline[i] + (recon[i - bytewidth] >> 1u); + } + 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]*/ + } + + /* Unroll independent paths of the paeth predictor. A 6x and 8x version would also be possible but that + adds too much code. Whether this actually speeds anything up at all depends on compiler and settings. */ + if (bytewidth >= 4) { + for (; i + 3 < length; i += 4) { + size_t j = i - bytewidth; + unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3]; + unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3]; + unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3]; + unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2], q3 = precon[j + 3]; + recon[i + 0] = s0 + paethPredictor(r0, p0, q0); + recon[i + 1] = s1 + paethPredictor(r1, p1, q1); + recon[i + 2] = s2 + paethPredictor(r2, p2, q2); + recon[i + 3] = s3 + paethPredictor(r3, p3, q3); + } + } else if (bytewidth >= 3) { + for (; i + 2 < length; i += 3) { + size_t j = i - bytewidth; + unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2]; + unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2]; + unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2]; + unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2]; + recon[i + 0] = s0 + paethPredictor(r0, p0, q0); + recon[i + 1] = s1 + paethPredictor(r1, p1, q1); + recon[i + 2] = s2 + paethPredictor(r2, p2, q2); + } + } else if (bytewidth >= 2) { + for (; i + 1 < length; i += 2) { + size_t j = i - bytewidth; + unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1]; + unsigned char r0 = recon[j + 0], r1 = recon[j + 1]; + unsigned char p0 = precon[i + 0], p1 = precon[i + 1]; + unsigned char q0 = precon[j + 0], q1 = precon[j + 1]; + recon[i + 0] = s0 + paethPredictor(r0, p0, q0); + recon[i + 1] = s1 + paethPredictor(r1, p1, q1); + } + } + + for (; 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: invalid filter type given */ + } + return 0; +} + + +static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) +{ + /* For PNG filter method 0 + this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times) + out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline + w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel + in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes) */ + + unsigned y; + unsigned char* prevline = 0; + + /* bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise */ + size_t bytewidth = (bpp + 7u) / 8u; + /* the width of a scanline in bytes, not including the filter type */ + size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u; + + for (y = 0; y < h; ++y) { + size_t outindex = linebytes * y; + size_t inindex = (1 + linebytes) * y; /* the extra filterbyte added to each row */ + unsigned char filterType = in[inindex]; + CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes)); + prevline = &out[outindex]; + } + + return 0; +} + +/* in: Adam7 interlaced image, with no padding bits between scanlines, but between + reduced images so that each reduced image starts at a byte. + out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h + bpp: bits per pixel + out has the following size in bits: w * h * bpp. + in is possibly bigger due to padding bits between reduced images. + out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation + (because that's likely a little bit faster) + NOTE: comments about padding bits are only relevant if bpp < 8 */ +static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) +{ + unsigned passw[7], passh[7]; + size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned i; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + if (bpp >= 8) { + for(i = 0; i != 7; ++i) { + unsigned x, y, b; + size_t bytewidth = bpp / 8u; + for (y = 0; y < passh[i]; ++y) + for (x = 0; x < passw[i]; ++x) { + size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth; + size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w + ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth; + for (b = 0; b < bytewidth; ++b) { + out[pixeloutstart + b] = in[pixelinstart + b]; + } + } + } + } else /* bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers */ { + for (i = 0; i != 7; ++i) { + unsigned x, y, b; + unsigned ilinebits = bpp * passw[i]; + unsigned olinebits = bpp * w; + size_t obp, ibp; /* bit pointers (for out and in buffer) */ + for (y = 0; y < passh[i]; ++y) + for (x = 0; x < passw[i]; ++x) { + ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp); + obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp; + for (b = 0; b < bpp; ++b) { + unsigned char bit = readBitFromReversedStream(&ibp, in); + setBitOfReversedStream(&obp, out, bit); + } + } + } + } +} + + +static void removePaddingBits(unsigned char* out, const unsigned char* in, size_t olinebits, size_t ilinebits, unsigned h) +{ + /* After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need + to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers + for the Adam7 code, the color convert code and the output to the user. + in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must + have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits + also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7 + only useful if (ilinebits - olinebits) is a value in the range 1..7 */ + unsigned y; + size_t diff = ilinebits - olinebits; + size_t ibp = 0, obp = 0; /*input and output bit pointers*/ + for (y = 0; y < h; ++y) { + size_t x; + for (x = 0; x < olinebits; ++x) { + unsigned char bit = readBitFromReversedStream(&ibp, in); + setBitOfReversedStream(&obp, out, bit); + } + ibp += diff; + } +} + + +/* out must be buffer big enough to contain full image, and in must contain the full decompressed data from + the IDAT chunks (with filter index bytes and possible padding bits) + return value is error */ +static unsigned postProcessScanlines(unsigned char* out, unsigned char* in, unsigned w, unsigned h, const LodePNGInfo* info_png) +{ + /* This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype. + Steps: + *) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8) + *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace + NOTE: the in buffer will be overwritten with intermediate data! */ + unsigned bpp = lodepng_get_bpp_lct(info_png->color.colortype, info_png->color.bitdepth); + if (bpp == 0) return 31; /* error: invalid colortype */ + + if (info_png->interlace_method == 0) { + if (bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) { + CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp)); + removePaddingBits(out, in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h); + } + /* we can immediately filter into the out buffer, no other steps needed */ + else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp)); + } else /* interlace_method is 1 (Adam7) */ { + unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; + unsigned i; + + Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); + + for (i = 0; i != 7; ++i) { + CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp)); + /* TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline, + move bytes instead of bits or move not at all */ + if (bpp < 8) { + /* remove padding bits in scanlines; after this there still may be padding + bits between the different reduced images: each reduced image still starts nicely at a byte */ + removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp, ((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]); + } + } + Adam7_deinterlace(out, in, w, h, bpp); + } + return 0; +} + + +static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) +{ + unsigned pos = 0, i; + color->palettesize = chunkLength / 3u; + if (color->palettesize == 0 || color->palettesize > 256) return 38; /* error: palette too small or big */ + lodepng_color_mode_alloc_palette(color); + if (!color->palette && color->palettesize) { + color->palettesize = 0; + return 83; /* alloc fail */ + } + + for (i = 0; i != color->palettesize; ++i) { + color->palette[4 * i + 0] = data[pos++]; /*R*/ + color->palette[4 * i + 1] = data[pos++]; /*G*/ + color->palette[4 * i + 2] = data[pos++]; /*B*/ + color->palette[4 * i + 3] = 255; /*alpha*/ + } + + return 0; /* OK */ +} + + +static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) +{ + unsigned i; + if (color->colortype == LCT_PALETTE) { + /* error: more alpha values given than there are palette entries */ + if (chunkLength > color->palettesize) return 39; + + for (i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i]; + } else if (color->colortype == LCT_GREY) { + /* error: this chunk must be 2 bytes for grayscale image */ + if (chunkLength != 2) return 30; + + color->key_defined = 1; + color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1]; + } else if (color->colortype == LCT_RGB) { + /* error: this chunk must be 6 bytes for RGB image */ + if (chunkLength != 6) return 41; + + color->key_defined = 1; + color->key_r = 256u * data[0] + data[1]; + color->key_g = 256u * data[2] + data[3]; + color->key_b = 256u * data[4] + data[5]; + } + else return 42; /* error: tRNS chunk not allowed for other color models */ + + return 0; /* OK */ +} + + +/* 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; + unsigned char* idat; /*the data from idat chunks, zlib compressed*/ + size_t idatsize = 0; + unsigned char* scanlines = 0; + size_t scanlines_size = 0, expected_size = 0; + size_t outsize = 0; + + /* safe output values in case error happens */ + *out = 0; + *w = *h = 0; + + state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/ + if (state->error) return; + + if (lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) { + CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/ + } + + /*the input filesize is a safe upper bound for the sum of idat chunks size*/ + idat = (unsigned char*)malloc(insize); + if (!idat) CERROR_RETURN(state->error, 83); /*alloc fail*/ + + chunk = &in[33]; /*first byte of the first chunk after the header*/ + + /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. + IDAT data is put at the start of the in buffer*/ + while (!IEND && !state->error) { + unsigned chunkLength; + const unsigned char* data; /*the data in the chunk*/ + + /*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); + + /*for unknown chunk order*/ + //unsigned unknown = 0; + + /*IDAT chunk, containing compressed image data*/ + if (lodepng_chunk_type_equals(chunk, "IDAT")) { + size_t newsize; + if (lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95); + if (newsize > insize) CERROR_BREAK(state->error, 95); + lodepng_memcpy(idat + idatsize, data, chunkLength); + idatsize += chunkLength; + } 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; + } 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; + } 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; + } + +#if 0 //We don't use CRC + 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*/ + } +#endif + if (!IEND) chunk = lodepng_chunk_next_const(chunk, in + insize); + } + + if (state->info_png.color.colortype == LCT_PALETTE && !state->info_png.color.palette) { + state->error = 106; /* error: PNG file must have PLTE chunk if color type is palette */ + } + + if (!state->error) { + /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation. + If the decompressed size does not match the prediction, the image must be corrupt.*/ + if (state->info_png.interlace_method == 0) { + size_t bpp = lodepng_get_bpp_lct(state->info_png.color.colortype, state->info_png.color.bitdepth); + expected_size = lodepng_get_raw_size_idat(*w, *h, bpp); + } else { + size_t bpp = lodepng_get_bpp_lct(state->info_png.color.colortype, state->info_png.color.bitdepth); + /*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/ + expected_size = 0; + expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp); + if (*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp); + expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp); + if (*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp); + expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp); + if (*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp); + expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp); + } + state->error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state->decoder.zlibsettings); + } + + if (!state->error && scanlines_size != expected_size) state->error = 91; /*decompressed size doesn't match prediction*/ + free(idat); + + if (!state->error) { + outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color); + *out = (unsigned char*)malloc(outsize); + if (!*out) state->error = 83; /*alloc fail*/ + } + if (!state->error) { + lodepng_memset(*out, 0, outsize); + state->error = postProcessScanlines(*out, scanlines, *w, *h, &state->info_png); + } + free(scanlines); +} + + +static void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) +{ + settings->color_convert = 1; + settings->ignore_crc = 0; + settings->ignore_critical = 0; + settings->ignore_end = 0; + lodepng_decompress_settings_init(&settings->zlibsettings); +} + + +/************************************************************************/ +/* External Class Implementation */ +/************************************************************************/ + +/*read the information from the header and store it in the LodePNGInfo. return value is error*/ +unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize) +{ + unsigned width, height; + LodePNGInfo* info = &state->info_png; + if (insize == 0 || in == 0) { + CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/ + } + if (insize < 33) { + CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/ + } + + /* when decoding a new PNG image, make sure all parameters created after previous decoding are reset */ + /* TODO: remove this. One should use a new LodePNGState for new sessions */ + lodepng_info_cleanup(info); + lodepng_info_init(info); + + if (in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { + CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/ + } + if (lodepng_chunk_length(in + 8) != 13) { + CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/ + } + if (!lodepng_chunk_type_equals(in + 8, "IHDR")) { + CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/ + } + + /*read the values given in the header*/ + width = lodepng_read32bitInt(&in[16]); + height = lodepng_read32bitInt(&in[20]); + /*TODO: remove the undocumented feature that allows to give null pointers to width or height*/ + if (w) *w = width; + if (h) *h = height; + info->color.bitdepth = in[24]; + info->color.colortype = (LodePNGColorType)in[25]; + info->compression_method = in[26]; + info->filter_method = in[27]; + info->interlace_method = in[28]; + + /*errors returned only after the parsing so other values are still output*/ + + /*error: invalid image size*/ + if (width == 0 || height == 0) CERROR_RETURN_ERROR(state->error, 93); + /*error: invalid colortype or bitdepth combination*/ + state->error = checkColorValidity(info->color.colortype, info->color.bitdepth); + if (state->error) return state->error; + /*error: only compression method 0 is allowed in the specification*/ + if (info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32); + /*error: only filter method 0 is allowed in the specification*/ + if (info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33); + /*error: only interlace methods 0 and 1 exist in the specification*/ + if (info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34); + +#if 0 //thorvg don't use crc + 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*/ + } + } +#endif + return state->error; +} + + +unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize) +{ + *out = 0; + decodeGeneric(out, w, h, state, in, insize); + if (state->error) return state->error; + if (!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) { + /*same color type, no copying or converting of data needed*/ + /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype + the raw image has to the end user*/ + if (!state->decoder.color_convert) { + state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color); + if (state->error) return state->error; + } + } else { /*color conversion needed*/ + unsigned char* data = *out; + size_t outsize; + + /*TODO: check if this works according to the statement in the documentation: "The converter can convert + from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/ + if (!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA) && !(state->info_raw.bitdepth == 8)) { + return 56; /*unsupported color mode conversion*/ + } + + outsize = lodepng_get_raw_size(*w, *h, &state->info_raw); + *out = (unsigned char*)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); + free(data); + } + return state->error; +} + + +void lodepng_state_init(LodePNGState* state) +{ + lodepng_decoder_settings_init(&state->decoder); + 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); +}
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