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 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#include <cstdio>
34
35static void appendIntToVector(unsigned number, Vector<unsigned char>& vector)
36{
37 size_t offset = vector.size();
38 vector.grow(offset + 4);
39 vector[offset] = ((number >> 24) & 0xff);
40 vector[offset + 1] = ((number >> 16) & 0xff);
41 vector[offset + 2] = ((number >> 8) & 0xff);
42 vector[offset + 3] = (number & 0xff);
43}
44
45static void convertChecksumToPNGComment(const char* checksum, Vector<unsigned char>& bytesToAdd)
46{
47 // Chunks of PNG files are <length>, <type>, <data>, <crc>.
48 static const char textCommentPrefix[] = "\x00\x00\x00\x29tEXtchecksum\x00";
49 static const size_t prefixLength = sizeof(textCommentPrefix) - 1; // The -1 is for the null at the end of the char[].
50 static const size_t checksumLength = 32;
51
52 bytesToAdd.append(textCommentPrefix, prefixLength);
53 bytesToAdd.append(checksum, checksumLength);
54
55 Vector<unsigned char> dataToCrc;
56 dataToCrc.append(textCommentPrefix + 4, prefixLength - 4); // Don't include the chunk length in the crc.
57 dataToCrc.append(checksum, checksumLength);
58 unsigned crc32 = computeCrc(dataToCrc);
59
60 appendIntToVector(crc32, bytesToAdd);
61}
62
63static size_t offsetAfterIHDRChunk(const unsigned char* data, const size_t dataLength)
64{
65 const int pngHeaderLength = 8;
66 const int pngIHDRChunkLength = 25; // chunk length + "IHDR" + 13 bytes of data + checksum
67 return pngHeaderLength + pngIHDRChunkLength;
68}
69
70void printPNG(const unsigned char* data, const size_t dataLength, const char* checksum)
71{
72 Vector<unsigned char> bytesToAdd;
73 convertChecksumToPNGComment(checksum, bytesToAdd);
74
75 printf("Content-Type: %s\n", "image/png");
76 printf("Content-Length: %lu\n", static_cast<unsigned long>(dataLength + bytesToAdd.size()));
77
78 size_t insertOffset = offsetAfterIHDRChunk(data, dataLength);
79
80 fwrite(data, 1, insertOffset, stdout);
81 fwrite(bytesToAdd.data(), 1, bytesToAdd.size(), stdout);
82
83 const size_t bytesToWriteInOneChunk = 1 << 15;
84 data += insertOffset;
85 size_t dataRemainingToWrite = dataLength - insertOffset;
86 while (dataRemainingToWrite) {
87 size_t bytesToWriteInThisChunk = std::min(dataRemainingToWrite, bytesToWriteInOneChunk);
88 size_t bytesWritten = fwrite(data, 1, bytesToWriteInThisChunk, stdout);
89 if (bytesWritten != bytesToWriteInThisChunk)
90 break;
91 dataRemainingToWrite -= bytesWritten;
92 data += bytesWritten;
93 }
94}
95