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| 1 | +/* |
| 2 | + * Copyright (C) 2009 Apple, Inc. All rights reserved. |
| 3 | + * |
| 4 | + * Redistribution and use in source and binary forms, with or without |
| 5 | + * modification, are permitted provided that the following conditions |
| 6 | + * are met: |
| 7 | + * |
| 8 | + * 1. Redistributions of source code must retain the above copyright |
| 9 | + * notice, this list of conditions and the following disclaimer. |
| 10 | + * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | + * notice, this list of conditions and the following disclaimer in the |
| 12 | + * documentation and/or other materials provided with the distribution. |
| 13 | + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
| 14 | + * its contributors may be used to endorse or promote products derived |
| 15 | + * from this software without specific prior written permission. |
| 16 | + * |
| 17 | + * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
| 18 | + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 19 | + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 20 | + * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| 21 | + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 22 | + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| 23 | + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| 24 | + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 26 | + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | + */ |
| 28 | + |
| 29 | +#include "config.h" |
| 30 | +#include "PixelDumpSupport.h" |
| 31 | + |
| 32 | +#include "CyclicRedundancyCheck.h" |
| 33 | + |
| 34 | +static void appendIntToVector(unsigned number, Vector<unsigned char>& vector) |
| 35 | +{ |
| 36 | + size_t offset = vector.size(); |
| 37 | + vector.grow(offset + 4); |
| 38 | + vector[offset] = ((number >> 24) & 0xff); |
| 39 | + vector[offset + 1] = ((number >> 16) & 0xff); |
| 40 | + vector[offset + 2] = ((number >> 8) & 0xff); |
| 41 | + vector[offset + 3] = (number & 0xff); |
| 42 | +} |
| 43 | + |
| 44 | +static void convertChecksumToPNGComment(const char* checksum, Vector<unsigned char>& bytesToAdd) |
| 45 | +{ |
| 46 | + // Chunks of PNG files are <length>, <type>, <data>, <crc>. |
| 47 | + static const char textCommentPrefix[] = "\x00\x00\x00\x29tEXtchecksum\x00"; |
| 48 | + static const size_t prefixLength = sizeof(textCommentPrefix) - 1; // The -1 is for the null at the end of the char[]. |
| 49 | + static const size_t checksumLength = 32; |
| 50 | + |
| 51 | + bytesToAdd.append(textCommentPrefix, prefixLength); |
| 52 | + bytesToAdd.append(checksum, checksumLength); |
| 53 | + |
| 54 | + Vector<unsigned char> dataToCrc; |
| 55 | + dataToCrc.append(textCommentPrefix + 4, prefixLength - 4); // Don't include the chunk length in the crc. |
| 56 | + dataToCrc.append(checksum, checksumLength); |
| 57 | + unsigned crc32 = computeCrc(dataToCrc); |
| 58 | + |
| 59 | + appendIntToVector(crc32, bytesToAdd); |
| 60 | +} |
| 61 | + |
| 62 | +static size_t offsetAfterIHDRChunk(const unsigned char* data, const size_t dataLength) |
| 63 | +{ |
| 64 | + const int pngHeaderLength = 8; |
| 65 | + const int pngIHDRChunkLength = 25; // chunk length + "IHDR" + 13 bytes of data + checksum |
| 66 | + return pngHeaderLength + pngIHDRChunkLength; |
| 67 | +} |
| 68 | + |
| 69 | +void printPNG(const unsigned char* data, const size_t dataLength, const char* checksum) |
| 70 | +{ |
| 71 | + Vector<unsigned char> bytesToAdd; |
| 72 | + convertChecksumToPNGComment(checksum, bytesToAdd); |
| 73 | + |
| 74 | + printf("Content-Type: %s\n", "image/png"); |
| 75 | + printf("Content-Length: %lu\n", static_cast<unsigned long>(dataLength + bytesToAdd.size())); |
| 76 | + |
| 77 | + size_t insertOffset = offsetAfterIHDRChunk(data, dataLength); |
| 78 | + |
| 79 | + fwrite(data, 1, insertOffset, stdout); |
| 80 | + fwrite(bytesToAdd.data(), 1, bytesToAdd.size(), stdout); |
| 81 | + |
| 82 | + const size_t bytesToWriteInOneChunk = 1 << 15; |
| 83 | + data += insertOffset; |
| 84 | + size_t dataRemainingToWrite = dataLength - insertOffset; |
| 85 | + while (dataRemainingToWrite) { |
| 86 | + size_t bytesToWriteInThisChunk = std::min(dataRemainingToWrite, bytesToWriteInOneChunk); |
| 87 | + size_t bytesWritten = fwrite(data, 1, bytesToWriteInThisChunk, stdout); |
| 88 | + if (bytesWritten != bytesToWriteInThisChunk) |
| 89 | + break; |
| 90 | + dataRemainingToWrite -= bytesWritten; |
| 91 | + data += bytesWritten; |
| 92 | + } |
| 93 | +} |
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