1 /* 2 * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved. 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Library General Public 6 * License as published by the Free Software Foundation; either 7 * version 2 of the License, or (at your option) any later version. 8 * 9 * This library is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Library General Public License for more details. 13 * 14 * You should have received a copy of the GNU Library General Public License 15 * along with this library; see the file COPYING.LIB. If not, write to 16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 17 * Boston, MA 02110-1301, USA. 18 * 19 */ 20 21 #include "config.h" 22 #include "platform/image-decoders/ImageDecoder.h" 23 24 #include "platform/image-decoders/bmp/BMPImageDecoder.h" 25 #include "platform/image-decoders/gif/GIFImageDecoder.h" 26 #include "platform/image-decoders/ico/ICOImageDecoder.h" 27 #include "platform/image-decoders/jpeg/JPEGImageDecoder.h" 28 #include "platform/image-decoders/png/PNGImageDecoder.h" 29 #include "platform/image-decoders/webp/WEBPImageDecoder.h" 30 #include "wtf/PassOwnPtr.h" 31 32 namespace WebCore { 33 34 static unsigned copyFromSharedBuffer(char* buffer, unsigned bufferLength, const SharedBuffer& sharedBuffer, unsigned offset) 35 { 36 unsigned bytesExtracted = 0; 37 const char* moreData; 38 while (unsigned moreDataLength = sharedBuffer.getSomeData(moreData, offset)) { 39 unsigned bytesToCopy = std::min(bufferLength - bytesExtracted, moreDataLength); 40 memcpy(buffer + bytesExtracted, moreData, bytesToCopy); 41 bytesExtracted += bytesToCopy; 42 if (bytesExtracted == bufferLength) 43 break; 44 offset += bytesToCopy; 45 } 46 return bytesExtracted; 47 } 48 49 inline bool matchesGIFSignature(char* contents) 50 { 51 return !memcmp(contents, "GIF87a", 6) || !memcmp(contents, "GIF89a", 6); 52 } 53 54 inline bool matchesPNGSignature(char* contents) 55 { 56 return !memcmp(contents, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8); 57 } 58 59 inline bool matchesJPEGSignature(char* contents) 60 { 61 return !memcmp(contents, "\xFF\xD8\xFF", 3); 62 } 63 64 inline bool matchesWebPSignature(char* contents) 65 { 66 return !memcmp(contents, "RIFF", 4) && !memcmp(contents + 8, "WEBPVP", 6); 67 } 68 69 inline bool matchesBMPSignature(char* contents) 70 { 71 return !memcmp(contents, "BM", 2); 72 } 73 74 inline bool matchesICOSignature(char* contents) 75 { 76 return !memcmp(contents, "\x00\x00\x01\x00", 4); 77 } 78 79 inline bool matchesCURSignature(char* contents) 80 { 81 return !memcmp(contents, "\x00\x00\x02\x00", 4); 82 } 83 84 PassOwnPtr<ImageDecoder> ImageDecoder::create(const SharedBuffer& data, ImageSource::AlphaOption alphaOption, ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption) 85 { 86 static const unsigned longestSignatureLength = sizeof("RIFF????WEBPVP") - 1; 87 ASSERT(longestSignatureLength == 14); 88 89 size_t maxDecodedBytes = blink::Platform::current()->maxDecodedImageBytes(); 90 91 char contents[longestSignatureLength]; 92 if (copyFromSharedBuffer(contents, longestSignatureLength, data, 0) < longestSignatureLength) 93 return nullptr; 94 95 if (matchesJPEGSignature(contents)) 96 return adoptPtr(new JPEGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 97 98 if (matchesPNGSignature(contents)) 99 return adoptPtr(new PNGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 100 101 if (matchesGIFSignature(contents)) 102 return adoptPtr(new GIFImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 103 104 if (matchesICOSignature(contents) || matchesCURSignature(contents)) 105 return adoptPtr(new ICOImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 106 107 if (matchesWebPSignature(contents)) 108 return adoptPtr(new WEBPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 109 110 if (matchesBMPSignature(contents)) 111 return adoptPtr(new BMPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)); 112 113 return nullptr; 114 } 115 116 bool ImageDecoder::frameHasAlphaAtIndex(size_t index) const 117 { 118 return !frameIsCompleteAtIndex(index) || m_frameBufferCache[index].hasAlpha(); 119 } 120 121 bool ImageDecoder::frameIsCompleteAtIndex(size_t index) const 122 { 123 return (index < m_frameBufferCache.size()) && 124 (m_frameBufferCache[index].status() == ImageFrame::FrameComplete); 125 } 126 127 unsigned ImageDecoder::frameBytesAtIndex(size_t index) const 128 { 129 if (m_frameBufferCache.size() <= index || m_frameBufferCache[index].status() == ImageFrame::FrameEmpty) 130 return 0; 131 // FIXME: Use the dimension of the requested frame. 132 return m_size.area() * sizeof(ImageFrame::PixelData); 133 } 134 135 size_t ImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame) 136 { 137 // Don't clear if there are no frames or only one frame. 138 if (m_frameBufferCache.size() <= 1) 139 return 0; 140 141 size_t frameBytesCleared = 0; 142 for (size_t i = 0; i < m_frameBufferCache.size(); ++i) { 143 if (i != clearExceptFrame) { 144 frameBytesCleared += frameBytesAtIndex(i); 145 clearFrameBuffer(i); 146 } 147 } 148 return frameBytesCleared; 149 } 150 151 void ImageDecoder::clearFrameBuffer(size_t frameIndex) 152 { 153 m_frameBufferCache[frameIndex].clearPixelData(); 154 } 155 156 size_t ImageDecoder::findRequiredPreviousFrame(size_t frameIndex, bool frameRectIsOpaque) 157 { 158 ASSERT(frameIndex <= m_frameBufferCache.size()); 159 if (!frameIndex) { 160 // The first frame doesn't rely on any previous data. 161 return kNotFound; 162 } 163 164 const ImageFrame* currBuffer = &m_frameBufferCache[frameIndex]; 165 if ((frameRectIsOpaque || currBuffer->alphaBlendSource() == ImageFrame::BlendAtopBgcolor) 166 && currBuffer->originalFrameRect().contains(IntRect(IntPoint(), size()))) 167 return kNotFound; 168 169 // The starting state for this frame depends on the previous frame's 170 // disposal method. 171 size_t prevFrame = frameIndex - 1; 172 const ImageFrame* prevBuffer = &m_frameBufferCache[prevFrame]; 173 ASSERT(prevBuffer->requiredPreviousFrameIndexValid()); 174 175 switch (prevBuffer->disposalMethod()) { 176 case ImageFrame::DisposeNotSpecified: 177 case ImageFrame::DisposeKeep: 178 // prevFrame will be used as the starting state for this frame. 179 // FIXME: Be even smarter by checking the frame sizes and/or alpha-containing regions. 180 return prevFrame; 181 case ImageFrame::DisposeOverwritePrevious: 182 // Frames that use the DisposeOverwritePrevious method are effectively 183 // no-ops in terms of changing the starting state of a frame compared to 184 // the starting state of the previous frame, so skip over them and 185 // return the required previous frame of it. 186 return prevBuffer->requiredPreviousFrameIndex(); 187 case ImageFrame::DisposeOverwriteBgcolor: 188 // If the previous frame fills the whole image, then the current frame 189 // can be decoded alone. Likewise, if the previous frame could be 190 // decoded without reference to any prior frame, the starting state for 191 // this frame is a blank frame, so it can again be decoded alone. 192 // Otherwise, the previous frame contributes to this frame. 193 return (prevBuffer->originalFrameRect().contains(IntRect(IntPoint(), size())) 194 || (prevBuffer->requiredPreviousFrameIndex() == kNotFound)) ? kNotFound : prevFrame; 195 default: 196 ASSERT_NOT_REACHED(); 197 return kNotFound; 198 } 199 } 200 201 } // namespace WebCore 202
