From 60072c1d8089ffd3294e76636198d14710be95b8 Mon Sep 17 00:00:00 2001 From: Yann Herklotz Date: Sat, 9 Sep 2017 07:55:22 +0100 Subject: Restructuring --- yage/base/picopng.cpp | 1118 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1118 insertions(+) create mode 100644 yage/base/picopng.cpp (limited to 'yage/base/picopng.cpp') diff --git a/yage/base/picopng.cpp b/yage/base/picopng.cpp new file mode 100644 index 00000000..dcc4b367 --- /dev/null +++ b/yage/base/picopng.cpp @@ -0,0 +1,1118 @@ +#include +#include + +namespace yage +{ + +/* + decodePNG: The picoPNG function, decodes a PNG file buffer in memory, into a + raw pixel buffer. + out_image: output parameter, this will contain the raw pixels after decoding. + By default the output is 32-bit RGBA color. + The std::vector is automatically resized to the correct size. + image_width: output_parameter, this will contain the width of the image in + pixels. + image_height: output_parameter, this will contain the height of the image in + pixels. + in_png: pointer to the buffer of the PNG file in memory. To get it from a file + on + disk, load it and store it in a memory buffer yourself first. + in_size: size of the input PNG file in bytes. + convert_to_rgba32: optional parameter, true by default. + Set to true to get the output in RGBA 32-bit (8 bit per channel) color format + no matter what color type the original PNG image had. This gives predictable, + useable data from any random input PNG. + Set to false to do no color conversion at all. The result then has the same + data + type as the PNG image, which can range from 1 bit to 64 bits per pixel. + Information about the color type or palette colors are not provided. You need + to know this information yourself to be able to use the data so this only + works for trusted PNG files. Use LodePNG instead of picoPNG if you need this + information. + return: 0 if success, not 0 if some error occured. +*/ +int decodePNG(std::vector &out_image, unsigned long &image_width, + unsigned long &image_height, const unsigned char *in_png, + size_t in_size, bool convert_to_rgba32) +{ + // picoPNG version 20101224 + // Copyright (c) 2005-2010 Lode Vandevenne + // + // This software is provided 'as-is', without any express or implied + // warranty. In no event will the authors be held liable for any damages + // arising from the use of this software. + // + // Permission is granted to anyone to use this software for any purpose, + // including commercial applications, and to alter it and redistribute it + // freely, subject to the following restrictions: + // + // 1. The origin of this software must not be misrepresented; you must + // not + // claim that you wrote the original software. If you use this software + // in a product, an acknowledgment in the product documentation would be + // appreciated but is not required. + // 2. Altered source versions must be plainly marked as such, and must + // not be + // misrepresented as being the original software. + // 3. This notice may not be removed or altered from any source + // distribution. + + // picoPNG is a PNG decoder in one C++ function of around 500 lines. Use + // picoPNG for + // programs that need only 1 .cpp file. Since it's a single function, it's + // very limited, + // it can convert a PNG to raw pixel data either converted to 32-bit RGBA + // color or + // with no color conversion at all. For anything more complex, another tiny + // library + // is available: LodePNG (lodepng.c(pp)), which is a single source and + // header file. + // Apologies for the compact code style, it's to make this tiny. + + static const unsigned long LENBASE[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}; + static const unsigned long LENEXTRA[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}; + static const unsigned long DISTBASE[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}; + static const unsigned long DISTEXTRA[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}; + static const unsigned long CLCL[19] = { + 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, + 11, 4, 12, 3, 13, 2, 14, 1, 15}; // code length code lengths + struct Zlib // nested functions for zlib decompression + { + static unsigned long readBitFromStream(size_t &bitp, + const unsigned char *bits) + { + unsigned long result = (bits[bitp >> 3] >> (bitp & 0x7)) & 1; + bitp++; + return result; + } + static unsigned long readBitsFromStream(size_t &bitp, + const unsigned char *bits, + size_t nbits) + { + unsigned long result = 0; + for (size_t i = 0; i < nbits; i++) { + result += (readBitFromStream(bitp, bits)) << i; + } + return result; + } + struct HuffmanTree { + int makeFromLengths(const std::vector &bitlen, + unsigned long maxbitlen) + { // make tree given the lengths + unsigned long numcodes = (unsigned long)(bitlen.size()), + treepos = 0, nodefilled = 0; + std::vector tree1d(numcodes), + blcount(maxbitlen + 1, 0), nextcode(maxbitlen + 1, 0); + for (unsigned long bits = 0; bits < numcodes; bits++) { + blcount[bitlen[bits]]++; // count number of instances of + } + // each code length + for (unsigned long bits = 1; bits <= maxbitlen; bits++) { + nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) + << 1; + } + for (unsigned long n = 0; n < numcodes; n++) { + if (bitlen[n] != 0) { + tree1d[n] = + nextcode[bitlen[n]]++; // generate all the codes + } + } + tree2d.clear(); + tree2d.resize(numcodes * 2, 32767); // 32767 here means the + // tree2d isn't filled + // there yet + for (unsigned long n = 0; n < numcodes; n++) { // the codes + for (unsigned long i = 0; i < bitlen[n]; + i++) // the bits for this code + { + unsigned long bit = + (tree1d[n] >> (bitlen[n] - i - 1)) & 1; + if (treepos > numcodes - 2) { + return 55; + } + if (tree2d[2 * treepos + bit] == + 32767) // not yet filled in + { + if (i + 1 == bitlen[n]) { + tree2d[2 * treepos + bit] = n; + treepos = 0; + } // last bit + else { + tree2d[2 * treepos + bit] = + ++nodefilled + numcodes; + treepos = nodefilled; + } // addresses are encoded as values > numcodes + } else { + treepos = tree2d[2 * treepos + bit] - + numcodes; // subtract numcodes from + } + // address to get address value + } + } + return 0; + } + int decode(bool &decoded, unsigned long &result, size_t &treepos, + unsigned long bit) const + { // Decodes a symbol from the tree + unsigned long numcodes = (unsigned long)tree2d.size() / 2; + if (treepos >= numcodes) { + return 11; // error: you appeared outside the codetree + } + result = tree2d[2 * treepos + bit]; + decoded = (result < numcodes); + treepos = decoded ? 0 : result - numcodes; + return 0; + } + std::vector tree2d; // 2D representation of a + // huffman tree: The one + // dimension is "0" or "1", the + // other contains all nodes and + // leaves of the tree. + }; + struct Inflator { + int error; + void inflate(std::vector &out, + const std::vector &in, size_t inpos = 0) + { + size_t bp = 0, pos = 0; // bit pointer and byte pointer + error = 0; + unsigned long BFINAL = 0; + while (!BFINAL && !error) { + if (bp >> 3 >= in.size()) { + error = 52; + return; + } // error, bit pointer will jump past memory + BFINAL = readBitFromStream(bp, &in[inpos]); + unsigned long BTYPE = readBitFromStream(bp, &in[inpos]); + BTYPE += 2 * readBitFromStream(bp, &in[inpos]); + if (BTYPE == 3) { + error = 20; + return; + } // error: invalid BTYPE + else if (BTYPE == 0) { + inflateNoCompression(out, &in[inpos], bp, pos, + in.size()); + } else { + inflateHuffmanBlock(out, &in[inpos], bp, pos, in.size(), + BTYPE); + } + } + if (!error) { + out.resize(pos); // Only now we know the true size of out, + } + // resize it to that + } + void generateFixedTrees(HuffmanTree &tree, + HuffmanTree &treeD) // get the tree of a + // deflated block with + // fixed tree + { + std::vector bitlen(288, 8), bitlenD(32, 5); + ; + for (size_t i = 144; i <= 255; i++) { + bitlen[i] = 9; + } + for (size_t i = 256; i <= 279; i++) { + bitlen[i] = 7; + } + tree.makeFromLengths(bitlen, 15); + treeD.makeFromLengths(bitlenD, 15); + } + HuffmanTree codetree, codetreeD, + codelengthcodetree; // the code tree for Huffman codes, dist + // codes, and code length codes + unsigned long huffmanDecodeSymbol(const unsigned char *in, + size_t &bp, + const HuffmanTree &codetree, + size_t inlength) + { // decode a single symbol from given list of + // bits with given code tree. return value + // is the symbol + bool decoded; + unsigned long ct; + for (size_t treepos = 0;;) { + if ((bp & 0x07) == 0 && (bp >> 3) > inlength) { + error = 10; + return 0; + } // error: end reached without endcode + error = codetree.decode(decoded, ct, treepos, + readBitFromStream(bp, in)); + if (error) { + return 0; // stop, an error happened + } + if (decoded) { + return ct; + } + } + } + void getTreeInflateDynamic(HuffmanTree &tree, HuffmanTree &treeD, + const unsigned char *in, size_t &bp, + size_t inlength) + { // get the tree of a deflated block with + // dynamic tree, the tree itself is also + // Huffman compressed with a known tree + std::vector bitlen(288, 0), bitlenD(32, 0); + if (bp >> 3 >= inlength - 2) { + error = 49; + return; + } // the bit pointer is or will go past the memory + size_t HLIT = readBitsFromStream(bp, in, 5) + + 257; // number of literal/length codes + 257 + size_t HDIST = readBitsFromStream(bp, in, 5) + + 1; // number of dist codes + 1 + size_t HCLEN = readBitsFromStream(bp, in, 4) + + 4; // number of code length codes + 4 + std::vector codelengthcode( + 19); // lengths of tree to decode the lengths of the + // dynamic tree + for (size_t i = 0; i < 19; i++) { + codelengthcode[CLCL[i]] = + (i < HCLEN) ? readBitsFromStream(bp, in, 3) : 0; + } + error = codelengthcodetree.makeFromLengths(codelengthcode, 7); + if (error) { + return; + } + size_t i = 0, replength; + while (i < HLIT + HDIST) { + unsigned long code = huffmanDecodeSymbol( + in, bp, codelengthcodetree, inlength); + if (error) { + return; + } + if (code <= 15) { + if (i < HLIT) { + bitlen[i++] = code; + } else { + bitlenD[i++ - HLIT] = code; + } + } // a length code + else if (code == 16) // repeat previous + { + if (bp >> 3 >= inlength) { + error = 50; + return; + } // error, bit pointer jumps past memory + replength = 3 + readBitsFromStream(bp, in, 2); + unsigned long value; // set value to the previous code + if ((i - 1) < HLIT) { + value = bitlen[i - 1]; + } else { + value = bitlenD[i - HLIT - 1]; + } + for (size_t n = 0; n < replength; + n++) // repeat this value in the next lengths + { + if (i >= HLIT + HDIST) { + error = 13; + return; + } // error: i is larger than the amount of codes + if (i < HLIT) { + bitlen[i++] = value; + } else { + bitlenD[i++ - HLIT] = value; + } + } + } else if (code == 17) // repeat "0" 3-10 times + { + if (bp >> 3 >= inlength) { + error = 50; + return; + } // error, bit pointer jumps past memory + replength = 3 + readBitsFromStream(bp, in, 3); + for (size_t n = 0; n < replength; + n++) // repeat this value in the next lengths + { + if (i >= HLIT + HDIST) { + error = 14; + return; + } // error: i is larger than the amount of codes + if (i < HLIT) { + bitlen[i++] = 0; + } else { + bitlenD[i++ - HLIT] = 0; + } + } + } else if (code == 18) // repeat "0" 11-138 times + { + if (bp >> 3 >= inlength) { + error = 50; + return; + } // error, bit pointer jumps past memory + replength = 11 + readBitsFromStream(bp, in, 7); + for (size_t n = 0; n < replength; + n++) // repeat this value in the next lengths + { + if (i >= HLIT + HDIST) { + error = 15; + return; + } // error: i is larger than the amount of codes + if (i < HLIT) { + bitlen[i++] = 0; + } else { + bitlenD[i++ - HLIT] = 0; + } + } + } else { + error = 16; + return; + } // error: somehow an unexisting code appeared. This can + // never happen. + } + if (bitlen[256] == 0) { + error = 64; + return; + } // the length of the end code 256 must be larger than 0 + error = tree.makeFromLengths(bitlen, 15); + if (error) { + return; // now we've finally got HLIT and HDIST, so + } + // generate the code trees, and the function is + // done + error = treeD.makeFromLengths(bitlenD, 15); + if (error) { + return; + } + } + void inflateHuffmanBlock(std::vector &out, + const unsigned char *in, size_t &bp, + size_t &pos, size_t inlength, + unsigned long btype) + { + if (btype == 1) { + generateFixedTrees(codetree, codetreeD); + } else if (btype == 2) { + getTreeInflateDynamic(codetree, codetreeD, in, bp, + inlength); + if (error) { + return; + } + } + for (;;) { + unsigned long code = + huffmanDecodeSymbol(in, bp, codetree, inlength); + if (error) { + return; + } + if (code == 256) { + return; // end code + } else if (code <= 255) // literal symbol + { + if (pos >= out.size()) { + out.resize((pos + 1) * 2); // reserve more room + } + out[pos++] = (unsigned char)(code); + } else if (code >= 257 && code <= 285) // length code + { + size_t length = LENBASE[code - 257], + numextrabits = LENEXTRA[code - 257]; + if ((bp >> 3) >= inlength) { + error = 51; + return; + } // error, bit pointer will jump past memory + length += readBitsFromStream(bp, in, numextrabits); + unsigned long codeD = + huffmanDecodeSymbol(in, bp, codetreeD, inlength); + if (error) { + return; + } + if (codeD > 29) { + error = 18; + return; + } // error: invalid dist code (30-31 are never used) + unsigned long dist = DISTBASE[codeD], + numextrabitsD = DISTEXTRA[codeD]; + if ((bp >> 3) >= inlength) { + error = 51; + return; + } // error, bit pointer will jump past memory + dist += readBitsFromStream(bp, in, numextrabitsD); + size_t start = pos, back = start - dist; // backwards + if (pos + length >= out.size()) { + out.resize((pos + length) * 2); // reserve more + } + // room + for (size_t i = 0; i < length; i++) { + out[pos++] = out[back++]; + if (back >= start) { + back = start - dist; + } + } + } + } + } + void inflateNoCompression(std::vector &out, + const unsigned char *in, size_t &bp, + size_t &pos, size_t inlength) + { + while ((bp & 0x7) != 0) { + bp++; // go to first boundary of byte + } + size_t p = bp / 8; + if (p >= inlength - 4) { + error = 52; + return; + } // error, bit pointer will jump past memory + unsigned long LEN = in[p] + 256 * in[p + 1], + NLEN = in[p + 2] + 256 * in[p + 3]; + p += 4; + if (LEN + NLEN != 65535) { + error = 21; + return; + } // error: NLEN is not one's complement of LEN + if (pos + LEN >= out.size()) { + out.resize(pos + LEN); + } + if (p + LEN > inlength) { + error = 23; + return; + } // error: reading outside of in buffer + for (unsigned long n = 0; n < LEN; n++) { + out[pos++] = in[p++]; // read LEN bytes of literal data + } + bp = p * 8; + } + }; + int + decompress(std::vector &out, + const std::vector &in) // returns error value + { + Inflator inflator; + if (in.size() < 2) { + return 53; + } // error, size of zlib data too small + if ((in[0] * 256 + in[1]) % 31 != 0) { + return 24; + } // error: 256 * in[0] + in[1] must be a multiple of 31, the + // FCHECK value is supposed to be made that way + unsigned long CM = in[0] & 15, CINFO = (in[0] >> 4) & 15, + FDICT = (in[1] >> 5) & 1; + if (CM != 8 || CINFO > 7) { + return 25; + } // error: only compression method 8: inflate with sliding window + // of 32k is supported by the PNG spec + if (FDICT != 0) { + return 26; + } // error: the specification of PNG says about the zlib stream: + // "The additional flags shall not specify a preset dictionary." + inflator.inflate(out, in, 2); + return inflator + .error; // note: adler32 checksum was skipped and ignored + } + }; + struct PNG // nested functions for PNG decoding + { + struct Info { + unsigned long width, height, colorType, bitDepth, compressionMethod, + filterMethod, interlaceMethod, key_r, key_g, key_b; + bool key_defined; // is a transparent color key given? + std::vector palette; + } info; + int error; + void decode(std::vector &out, const unsigned char *in, + size_t size, bool convert_to_rgba32) + { + error = 0; + if (size == 0 || in == nullptr) { + error = 48; + return; + } // the given data is empty + readPngHeader(&in[0], size); + if (error) { + return; + } + size_t pos = 33; // first byte of the first chunk after the header + std::vector idat; // the data from idat chunks + bool IEND = false, known_type = true; + info.key_defined = false; + while (!IEND) // loop through the chunks, ignoring unknown chunks + // and stopping at IEND chunk. IDAT data is put at + // the start of the in buffer + { + if (pos + 8 >= size) { + error = 30; + return; + } // error: size of the in buffer too small to contain next + // chunk + size_t chunkLength = read32bitInt(&in[pos]); + pos += 4; + if (chunkLength > 2147483647) { + error = 63; + return; + } + if (pos + chunkLength >= size) { + error = 35; + return; + } // error: size of the in buffer too small to contain next + // chunk + if (in[pos + 0] == 'I' && in[pos + 1] == 'D' && + in[pos + 2] == 'A' && + in[pos + 3] == + 'T') // IDAT chunk, containing compressed image data + { + idat.insert(idat.end(), &in[pos + 4], + &in[pos + 4 + chunkLength]); + pos += (4 + chunkLength); + } else if (in[pos + 0] == 'I' && in[pos + 1] == 'E' && + in[pos + 2] == 'N' && in[pos + 3] == 'D') { + pos += 4; + IEND = true; + } else if (in[pos + 0] == 'P' && in[pos + 1] == 'L' && + in[pos + 2] == 'T' && + in[pos + 3] == 'E') // palette chunk (PLTE) + { + pos += 4; // go after the 4 letters + info.palette.resize(4 * (chunkLength / 3)); + if (info.palette.size() > (4 * 256)) { + error = 38; + return; + } // error: palette too big + for (size_t i = 0; i < info.palette.size(); i += 4) { + for (size_t j = 0; j < 3; j++) { + info.palette[i + j] = in[pos++]; // RGB + } + info.palette[i + 3] = 255; // alpha + } + } else if (in[pos + 0] == 't' && in[pos + 1] == 'R' && + in[pos + 2] == 'N' && + in[pos + 3] == + 'S') // palette transparency chunk (tRNS) + { + pos += 4; // go after the 4 letters + if (info.colorType == 3) { + if (4 * chunkLength > info.palette.size()) { + error = 39; + return; + } // error: more alpha values given than there are + // palette entries + for (size_t i = 0; i < chunkLength; i++) { + info.palette[4 * i + 3] = in[pos++]; + } + } else if (info.colorType == 0) { + if (chunkLength != 2) { + error = 40; + return; + } // error: this chunk must be 2 bytes for greyscale + // image + info.key_defined = true; + info.key_r = info.key_g = info.key_b = + 256 * in[pos] + in[pos + 1]; + pos += 2; + } else if (info.colorType == 2) { + if (chunkLength != 6) { + error = 41; + return; + } // error: this chunk must be 6 bytes for RGB image + info.key_defined = true; + info.key_r = 256 * in[pos] + in[pos + 1]; + pos += 2; + info.key_g = 256 * in[pos] + in[pos + 1]; + pos += 2; + info.key_b = 256 * in[pos] + in[pos + 1]; + pos += 2; + } else { + error = 42; + return; + } // error: tRNS chunk not allowed for other color models + } else // it's not an implemented chunk type, so ignore it: + // skip over the data + { + if (!(in[pos + 0] & 32)) { + error = 69; + return; + } // error: unknown critical chunk (5th bit of first byte + // of chunk type is 0) + pos += (chunkLength + 4); // skip 4 letters and + // uninterpreted data of + // unimplemented chunk + known_type = false; + } + pos += 4; // step over CRC (which is ignored) + } + unsigned long bpp = getBpp(info); + std::vector scanlines( + ((info.width * (info.height * bpp + 7)) / 8) + + info.height); // now the out buffer will be filled + Zlib zlib; // decompress with the Zlib decompressor + error = zlib.decompress(scanlines, idat); + if (error) { + return; // stop if the zlib decompressor returned an error + } + size_t bytewidth = (bpp + 7) / 8, + outlength = (info.height * info.width * bpp + 7) / 8; + out.resize(outlength); // time to fill the out buffer + unsigned char *out_ = + outlength ? &out[0] : nullptr; // use a regular pointer to the + // std::vector for faster code if + // compiled without optimization + if (info.interlaceMethod == 0) // no interlace, just filter + { + size_t linestart = 0, + linelength = (info.width * bpp + 7) / + 8; // length in bytes of a scanline, + // excluding the filtertype byte + if (bpp >= 8) { // byte per byte + for (unsigned long y = 0; y < info.height; y++) { + unsigned long filterType = scanlines[linestart]; + const unsigned char *prevline = + (y == 0) ? nullptr + : &out_[(y - 1) * info.width * bytewidth]; + unFilterScanline(&out_[linestart - y], + &scanlines[linestart + 1], prevline, + bytewidth, filterType, linelength); + if (error) { + return; + } + linestart += + (1 + linelength); // go to start of next scanline + } + } else // less than 8 bits per pixel, so fill it up bit per bit + { + std::vector templine( + (info.width * bpp + 7) >> 3); // only used if bpp < 8 + for (size_t y = 0, obp = 0; y < info.height; y++) { + unsigned long filterType = scanlines[linestart]; + const unsigned char *prevline = + (y == 0) ? nullptr + : &out_[(y - 1) * info.width * bytewidth]; + unFilterScanline(&templine[0], + &scanlines[linestart + 1], prevline, + bytewidth, filterType, linelength); + if (error) { + return; + } + for (size_t bp = 0; bp < info.width * bpp;) { + setBitOfReversedStream( + obp, out_, + readBitFromReversedStream(bp, &templine[0])); + } + linestart += + (1 + linelength); // go to start of next scanline + } + } + } else // interlaceMethod is 1 (Adam7) + { + size_t passw[7] = {(info.width + 7) / 8, (info.width + 3) / 8, + (info.width + 3) / 4, (info.width + 1) / 4, + (info.width + 1) / 2, (info.width + 0) / 2, + (info.width + 0) / 1}; + size_t passh[7] = {(info.height + 7) / 8, (info.height + 7) / 8, + (info.height + 3) / 8, (info.height + 3) / 4, + (info.height + 1) / 4, (info.height + 1) / 2, + (info.height + 0) / 2}; + size_t passstart[7] = {0}; + size_t pattern[28] = {0, 4, 0, 2, 0, 1, 0, 0, 0, 4, + 0, 2, 0, 1, 8, 8, 4, 4, 2, 2, + 1, 8, 8, 8, 4, 4, 2, 2}; // values for the + // adam7 passes + for (int i = 0; i < 6; i++) { + passstart[i + 1] = passstart[i] + + passh[i] * ((passw[i] ? 1 : 0) + + (passw[i] * bpp + 7) / 8); + } + std::vector scanlineo((info.width * bpp + 7) / + 8), + scanlinen((info.width * bpp + 7) / + 8); //"old" and "new" scanline + for (int i = 0; i < 7; i++) { + adam7Pass(&out_[0], &scanlinen[0], &scanlineo[0], + &scanlines[passstart[i]], info.width, pattern[i], + pattern[i + 7], pattern[i + 14], pattern[i + 21], + passw[i], passh[i], bpp); + } + } + if (convert_to_rgba32 && (info.colorType != 6 || + info.bitDepth != 8)) // conversion needed + { + std::vector data = out; + error = convert(out, &data[0], info, info.width, info.height); + } + } + void readPngHeader(const unsigned char *in, + size_t inlength) // read the information from the + // header and store it in the Info + { + if (inlength < 29) { + error = 27; + return; + } // error: the data length is smaller than the length of the + // header + 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) { + error = 28; + return; + } // no PNG signature + if (in[12] != 'I' || in[13] != 'H' || in[14] != 'D' || + in[15] != 'R') { + error = 29; + return; + } // error: it doesn't start with a IHDR chunk! + info.width = read32bitInt(&in[16]); + info.height = read32bitInt(&in[20]); + info.bitDepth = in[24]; + info.colorType = in[25]; + info.compressionMethod = in[26]; + if (in[26] != 0) { + error = 32; + return; + } // error: only compression method 0 is allowed in the + // specification + info.filterMethod = in[27]; + if (in[27] != 0) { + error = 33; + return; + } // error: only filter method 0 is allowed in the specification + info.interlaceMethod = in[28]; + if (in[28] > 1) { + error = 34; + return; + } // error: only interlace methods 0 and 1 exist in the + // specification + error = checkColorValidity(info.colorType, info.bitDepth); + } + void unFilterScanline(unsigned char *recon, + const unsigned char *scanline, + const unsigned char *precon, size_t bytewidth, + unsigned long filterType, size_t length) + { + switch (filterType) { + case 0: + for (size_t i = 0; i < length; i++) { + recon[i] = scanline[i]; + } + break; + case 1: + for (size_t i = 0; i < bytewidth; i++) { + recon[i] = scanline[i]; + } + for (size_t i = bytewidth; i < length; i++) { + recon[i] = scanline[i] + recon[i - bytewidth]; + } + break; + case 2: + if (precon) { + for (size_t i = 0; i < length; i++) { + recon[i] = scanline[i] + precon[i]; + } + } else { + for (size_t i = 0; i < length; i++) { + recon[i] = scanline[i]; + } + } + break; + case 3: + if (precon) { + for (size_t i = 0; i < bytewidth; i++) { + recon[i] = scanline[i] + precon[i] / 2; + } + for (size_t i = bytewidth; i < length; i++) { + recon[i] = scanline[i] + + ((recon[i - bytewidth] + precon[i]) / 2); + } + } else { + for (size_t i = 0; i < bytewidth; i++) { + recon[i] = scanline[i]; + } + for (size_t i = bytewidth; i < length; i++) { + recon[i] = scanline[i] + recon[i - bytewidth] / 2; + } + } + break; + case 4: + if (precon) { + for (size_t i = 0; i < bytewidth; i++) { + recon[i] = + scanline[i] + paethPredictor(0, precon[i], 0); + } + for (size_t i = bytewidth; i < length; i++) { + recon[i] = + scanline[i] + paethPredictor(recon[i - bytewidth], + precon[i], + precon[i - bytewidth]); + } + } else { + for (size_t i = 0; i < bytewidth; i++) { + recon[i] = scanline[i]; + } + for (size_t i = bytewidth; i < length; i++) { + recon[i] = scanline[i] + + paethPredictor(recon[i - bytewidth], 0, 0); + } + } + break; + default: + error = 36; + return; // error: unexisting filter type given + } + } + void adam7Pass(unsigned char *out, unsigned char *linen, + unsigned char *lineo, const unsigned char *in, + unsigned long w, size_t passleft, size_t passtop, + size_t spacex, size_t spacey, size_t passw, size_t passh, + unsigned long bpp) + { // filter and reposition the pixels + // into the output when the image + // is Adam7 interlaced. This + // function can only do it after + // the full image is already + // decoded. The out buffer must + // have the correct allocated + // memory size already. + if (passw == 0) { + return; + } + size_t bytewidth = (bpp + 7) / 8, + linelength = 1 + ((bpp * passw + 7) / 8); + for (unsigned long y = 0; y < passh; y++) { + unsigned char filterType = in[y * linelength], + *prevline = (y == 0) ? nullptr : lineo; + unFilterScanline(linen, &in[y * linelength + 1], prevline, + bytewidth, filterType, (w * bpp + 7) / 8); + if (error) { + return; + } + if (bpp >= 8) { + for (size_t i = 0; i < passw; i++) { + for (size_t b = 0; b < bytewidth; + b++) { // b = current byte of this pixel + out[bytewidth * w * (passtop + spacey * y) + + bytewidth * (passleft + spacex * i) + b] = + linen[bytewidth * i + b]; + } + } + } else { + for (size_t i = 0; i < passw; i++) { + size_t obp = bpp * w * (passtop + spacey * y) + + bpp * (passleft + spacex * i), + bp = i * bpp; + for (size_t b = 0; b < bpp; b++) { + setBitOfReversedStream( + obp, out, + readBitFromReversedStream(bp, &linen[0])); + } + } + } + unsigned char *temp = linen; + linen = lineo; + lineo = temp; // swap the two buffer pointers "line old" and + // "line new" + } + } + static unsigned long + readBitFromReversedStream(size_t &bitp, const unsigned char *bits) + { + unsigned long result = (bits[bitp >> 3] >> (7 - (bitp & 0x7))) & 1; + bitp++; + return result; + } + static unsigned long + readBitsFromReversedStream(size_t &bitp, const unsigned char *bits, + unsigned long nbits) + { + unsigned long result = 0; + for (size_t i = nbits - 1; i < nbits; i--) { + result += ((readBitFromReversedStream(bitp, bits)) << i); + } + return result; + } + void setBitOfReversedStream(size_t &bitp, unsigned char *bits, + unsigned long bit) + { + bits[bitp >> 3] |= (bit << (7 - (bitp & 0x7))); + bitp++; + } + unsigned long read32bitInt(const unsigned char *buffer) + { + return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | + buffer[3]; + } + int checkColorValidity( + unsigned long colorType, + unsigned long bd) // return type is a LodePNG error code + { + if ((colorType == 2 || colorType == 4 || colorType == 6)) { + if (!(bd == 8 || bd == 16)) { + return 37; + } else { + return 0; + } + } else if (colorType == 0) { + if (!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) { + return 37; + } else { + return 0; + } + } else if (colorType == 3) { + if (!(bd == 1 || bd == 2 || bd == 4 || bd == 8)) { + return 37; + } else { + return 0; + } + } else { + return 31; // unexisting color type + } + } + unsigned long getBpp(const Info &info) + { + if (info.colorType == 2) { + return (3 * info.bitDepth); + } else if (info.colorType >= 4) { + return (info.colorType - 2) * info.bitDepth; + } else { + return info.bitDepth; + } + } + int convert(std::vector &out, const unsigned char *in, + Info &infoIn, unsigned long w, unsigned long h) + { // converts from any color type to + // 32-bit. return value = LodePNG error + // code + size_t numpixels = w * h, bp = 0; + out.resize(numpixels * 4); + unsigned char *out_ = + out.empty() + ? nullptr + : &out[0]; // faster if compiled without optimization + if (infoIn.bitDepth == 8 && infoIn.colorType == 0) { // greyscale + for (size_t i = 0; i < numpixels; i++) { + out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = in[i]; + out_[4 * i + 3] = + (infoIn.key_defined && in[i] == infoIn.key_r) ? 0 : 255; + } + } else if (infoIn.bitDepth == 8 && infoIn.colorType == 2) { // RGB + // color + for (size_t i = 0; i < numpixels; i++) { + for (size_t c = 0; c < 3; c++) { + out_[4 * i + c] = in[3 * i + c]; + } + out_[4 * i + 3] = (infoIn.key_defined == 1 && + in[3 * i + 0] == infoIn.key_r && + in[3 * i + 1] == infoIn.key_g && + in[3 * i + 2] == infoIn.key_b) + ? 0 + : 255; + } + } else if (infoIn.bitDepth == 8 && + infoIn.colorType == 3) { // indexed color (palette) + for (size_t i = 0; i < numpixels; i++) { + if (4U * in[i] >= infoIn.palette.size()) { + return 46; + } + for (size_t c = 0; c < 4; c++) { + out_[4 * i + c] = + infoIn.palette[4 * in[i] + c]; // get rgb colors + } + // from the palette + } + } else if (infoIn.bitDepth == 8 && + infoIn.colorType == 4) { // greyscale with alpha + for (size_t i = 0; i < numpixels; i++) { + out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = + in[2 * i + 0]; + out_[4 * i + 3] = in[2 * i + 1]; + } + } else if (infoIn.bitDepth == 8 && infoIn.colorType == 6) { + for (size_t i = 0; i < numpixels; i++) { + for (size_t c = 0; c < 4; c++) { + out_[4 * i + c] = in[4 * i + c]; // RGB with alpha + } + } + } else if (infoIn.bitDepth == 16 && + infoIn.colorType == 0) { // greyscale + for (size_t i = 0; i < numpixels; i++) { + out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = + in[2 * i]; + out_[4 * i + 3] = (infoIn.key_defined && + 256U * in[i] + in[i + 1] == infoIn.key_r) + ? 0 + : 255; + } + } else if (infoIn.bitDepth == 16 && + infoIn.colorType == 2) { // RGB color + for (size_t i = 0; i < numpixels; i++) { + for (size_t c = 0; c < 3; c++) { + out_[4 * i + c] = in[6 * i + 2 * c]; + } + out_[4 * i + 3] = + (infoIn.key_defined && + 256U * in[6 * i + 0] + in[6 * i + 1] == infoIn.key_r && + 256U * in[6 * i + 2] + in[6 * i + 3] == infoIn.key_g && + 256U * in[6 * i + 4] + in[6 * i + 5] == infoIn.key_b) + ? 0 + : 255; + } + } else if (infoIn.bitDepth == 16 && + infoIn.colorType == 4) { // greyscale with alpha + for (size_t i = 0; i < numpixels; i++) { + out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = + in[4 * i]; // most significant byte + out_[4 * i + 3] = in[4 * i + 2]; + } + } else if (infoIn.bitDepth == 16 && infoIn.colorType == 6) { + for (size_t i = 0; i < numpixels; i++) { + for (size_t c = 0; c < 4; c++) { + out_[4 * i + c] = in[8 * i + 2 * c]; // RGB with alpha + } + } + } else if (infoIn.bitDepth < 8 && + infoIn.colorType == 0) { // greyscale + for (size_t i = 0; i < numpixels; i++) { + unsigned long value = + (readBitsFromReversedStream(bp, in, infoIn.bitDepth) * + 255) / + ((1 << infoIn.bitDepth) - + 1); // scale value from 0 to 255 + out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = + (unsigned char)(value); + out_[4 * i + 3] = + (infoIn.key_defined && value && + ((1U << infoIn.bitDepth) - 1U) == infoIn.key_r && + ((1U << infoIn.bitDepth) - 1U)) + ? 0 + : 255; + } + } else if (infoIn.bitDepth < 8 && + infoIn.colorType == 3) { // palette + for (size_t i = 0; i < numpixels; i++) { + unsigned long value = + readBitsFromReversedStream(bp, in, infoIn.bitDepth); + if (4 * value >= infoIn.palette.size()) { + return 47; + } + for (size_t c = 0; c < 4; c++) { + out_[4 * i + c] = + infoIn.palette[4 * value + c]; // get rgb colors + } + // from the palette + } + } + return 0; + } + unsigned char + paethPredictor(short a, short b, + short c) // Paeth predicter, used by PNG filter type 4 + { + short p = a + b - c, pa = p > a ? (p - a) : (a - p), + pb = p > b ? (p - b) : (b - p), + pc = p > c ? (p - c) : (c - p); + return (unsigned char)((pa <= pb && pa <= pc) ? a + : pb <= pc ? b : c); + } + }; + PNG decoder; + decoder.decode(out_image, in_png, in_size, convert_to_rgba32); + image_width = decoder.info.width; + image_height = decoder.info.height; + return decoder.error; +} + +} // namespace yage -- cgit