1 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* ***** BEGIN LICENSE BLOCK ***** 3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1 4 * 5 * The contents of this file are subject to the Mozilla Public License Version 6 * 1.1 (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * http://www.mozilla.org/MPL/ 9 * 10 * Software distributed under the License is distributed on an "AS IS" basis, 11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 12 * for the specific language governing rights and limitations under the 13 * License. 14 * 15 * The Original Code is Mozilla Communicator client code. 16 * 17 * The Initial Developer of the Original Code is 18 * Netscape Communications Corporation. 19 * Portions created by the Initial Developer are Copyright (C) 1998 20 * the Initial Developer. All Rights Reserved. 21 * 22 * Contributor(s): 23 * 24 * Alternatively, the contents of this file may be used under the terms of 25 * either the GNU General Public License Version 2 or later (the "GPL"), or 26 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), 27 * in which case the provisions of the GPL or the LGPL are applicable instead 28 * of those above. If you wish to allow use of your version of this file only 29 * under the terms of either the GPL or the LGPL, and not to allow others to 30 * use your version of this file under the terms of the MPL, indicate your 31 * decision by deleting the provisions above and replace them with the notice 32 * and other provisions required by the GPL or the LGPL. If you do not delete 33 * the provisions above, a recipient may use your version of this file under 34 * the terms of any one of the MPL, the GPL or the LGPL. 35 * 36 * ***** END LICENSE BLOCK ***** */ 37 38 #ifndef GIFImageReader_h 39 #define GIFImageReader_h 40 41 // Define ourselves as the clientPtr. Mozilla just hacked their C++ callback class into this old C decoder, 42 // so we will too. 43 #include "platform/SharedBuffer.h" 44 #include "platform/image-decoders/gif/GIFImageDecoder.h" 45 #include "wtf/Noncopyable.h" 46 #include "wtf/OwnPtr.h" 47 #include "wtf/PassOwnPtr.h" 48 #include "wtf/Vector.h" 49 50 #define MAX_DICTIONARY_ENTRY_BITS 12 51 #define MAX_DICTIONARY_ENTRIES 4096 // 2^MAX_DICTIONARY_ENTRY_BITS 52 #define MAX_COLORS 256 53 #define BYTES_PER_COLORMAP_ENTRY 3 54 55 const int cLoopCountNotSeen = -2; 56 57 // List of possible parsing states. 58 enum GIFState { 59 GIFType, 60 GIFGlobalHeader, 61 GIFGlobalColormap, 62 GIFImageStart, 63 GIFImageHeader, 64 GIFImageColormap, 65 GIFImageBody, 66 GIFLZWStart, 67 GIFLZW, 68 GIFSubBlock, 69 GIFExtension, 70 GIFControlExtension, 71 GIFConsumeBlock, 72 GIFSkipBlock, 73 GIFDone, 74 GIFCommentExtension, 75 GIFApplicationExtension, 76 GIFNetscapeExtensionBlock, 77 GIFConsumeNetscapeExtension, 78 GIFConsumeComment 79 }; 80 81 struct GIFFrameContext; 82 83 // LZW decoder state machine. 84 class GIFLZWContext { 85 WTF_MAKE_FAST_ALLOCATED; 86 public: GIFLZWContext(blink::GIFImageDecoder * client,const GIFFrameContext * frameContext)87 GIFLZWContext(blink::GIFImageDecoder* client, const GIFFrameContext* frameContext) 88 : codesize(0) 89 , codemask(0) 90 , clearCode(0) 91 , avail(0) 92 , oldcode(0) 93 , firstchar(0) 94 , bits(0) 95 , datum(0) 96 , ipass(0) 97 , irow(0) 98 , rowsRemaining(0) 99 , rowIter(0) 100 , m_client(client) 101 , m_frameContext(frameContext) 102 { } 103 104 bool prepareToDecode(); 105 bool outputRow(GIFRow::const_iterator rowBegin); 106 bool doLZW(const unsigned char* block, size_t bytesInBlock); hasRemainingRows()107 bool hasRemainingRows() { return rowsRemaining; } 108 109 private: 110 // LZW decoding states and output states. 111 int codesize; 112 int codemask; 113 int clearCode; // Codeword used to trigger dictionary reset. 114 int avail; // Index of next available slot in dictionary. 115 int oldcode; 116 unsigned char firstchar; 117 int bits; // Number of unread bits in "datum". 118 int datum; // 32-bit input buffer. 119 int ipass; // Interlace pass; Ranges 1-4 if interlaced. 120 size_t irow; // Current output row, starting at zero. 121 size_t rowsRemaining; // Rows remaining to be output. 122 123 unsigned short prefix[MAX_DICTIONARY_ENTRIES]; 124 unsigned char suffix[MAX_DICTIONARY_ENTRIES]; 125 unsigned short suffixLength[MAX_DICTIONARY_ENTRIES]; 126 GIFRow rowBuffer; // Single scanline temporary buffer. 127 GIFRow::iterator rowIter; 128 129 // Initialized during construction and read-only. 130 blink::GIFImageDecoder* m_client; 131 const GIFFrameContext* m_frameContext; 132 }; 133 134 // Data structure for one LZW block. 135 struct GIFLZWBlock { 136 WTF_MAKE_FAST_ALLOCATED; 137 public: GIFLZWBlockGIFLZWBlock138 GIFLZWBlock(size_t position, size_t size) 139 : blockPosition(position) 140 , blockSize(size) 141 { 142 } 143 144 size_t blockPosition; 145 size_t blockSize; 146 }; 147 148 class GIFColorMap { 149 WTF_MAKE_FAST_ALLOCATED; 150 public: 151 typedef Vector<blink::ImageFrame::PixelData> Table; 152 GIFColorMap()153 GIFColorMap() 154 : m_isDefined(false) 155 , m_position(0) 156 , m_colors(0) 157 { 158 } 159 160 // Set position and number of colors for the RGB table in the data stream. setTablePositionAndSize(size_t position,size_t colors)161 void setTablePositionAndSize(size_t position, size_t colors) 162 { 163 m_position = position; 164 m_colors = colors; 165 } setDefined()166 void setDefined() { m_isDefined = true; } isDefined()167 bool isDefined() const { return m_isDefined; } 168 169 // Build RGBA table using the data stream. 170 void buildTable(const unsigned char* data, size_t length); table()171 const Table& table() const { return m_table; } 172 173 private: 174 bool m_isDefined; 175 size_t m_position; 176 size_t m_colors; 177 Table m_table; 178 }; 179 180 // LocalFrame output state machine. 181 struct GIFFrameContext { 182 WTF_MAKE_FAST_ALLOCATED; WTF_MAKE_NONCOPYABLE(GIFFrameContext); 183 public: GIFFrameContextGIFFrameContext184 GIFFrameContext(int id) 185 : m_frameId(id) 186 , m_xOffset(0) 187 , m_yOffset(0) 188 , m_width(0) 189 , m_height(0) 190 , m_transparentPixel(kNotFound) 191 , m_disposalMethod(blink::ImageFrame::DisposeNotSpecified) 192 , m_dataSize(0) 193 , m_progressiveDisplay(false) 194 , m_interlaced(false) 195 , m_delayTime(0) 196 , m_currentLzwBlock(0) 197 , m_isComplete(false) 198 , m_isHeaderDefined(false) 199 , m_isDataSizeDefined(false) 200 { 201 } 202 ~GIFFrameContextGIFFrameContext203 ~GIFFrameContext() 204 { 205 } 206 addLzwBlockGIFFrameContext207 void addLzwBlock(size_t position, size_t size) 208 { 209 m_lzwBlocks.append(GIFLZWBlock(position, size)); 210 } 211 212 bool decode(const unsigned char* data, size_t length, blink::GIFImageDecoder* client, bool* frameDecoded); 213 frameIdGIFFrameContext214 int frameId() const { return m_frameId; } setRectGIFFrameContext215 void setRect(unsigned x, unsigned y, unsigned width, unsigned height) 216 { 217 m_xOffset = x; 218 m_yOffset = y; 219 m_width = width; 220 m_height = height; 221 } frameRectGIFFrameContext222 blink::IntRect frameRect() const { return blink::IntRect(m_xOffset, m_yOffset, m_width, m_height); } xOffsetGIFFrameContext223 unsigned xOffset() const { return m_xOffset; } yOffsetGIFFrameContext224 unsigned yOffset() const { return m_yOffset; } widthGIFFrameContext225 unsigned width() const { return m_width; } heightGIFFrameContext226 unsigned height() const { return m_height; } transparentPixelGIFFrameContext227 size_t transparentPixel() const { return m_transparentPixel; } setTransparentPixelGIFFrameContext228 void setTransparentPixel(size_t pixel) { m_transparentPixel = pixel; } disposalMethodGIFFrameContext229 blink::ImageFrame::DisposalMethod disposalMethod() const { return m_disposalMethod; } setDisposalMethodGIFFrameContext230 void setDisposalMethod(blink::ImageFrame::DisposalMethod disposalMethod) { m_disposalMethod = disposalMethod; } delayTimeGIFFrameContext231 unsigned delayTime() const { return m_delayTime; } setDelayTimeGIFFrameContext232 void setDelayTime(unsigned delay) { m_delayTime = delay; } isCompleteGIFFrameContext233 bool isComplete() const { return m_isComplete; } setCompleteGIFFrameContext234 void setComplete() { m_isComplete = true; } isHeaderDefinedGIFFrameContext235 bool isHeaderDefined() const { return m_isHeaderDefined; } setHeaderDefinedGIFFrameContext236 void setHeaderDefined() { m_isHeaderDefined = true; } isDataSizeDefinedGIFFrameContext237 bool isDataSizeDefined() const { return m_isDataSizeDefined; } dataSizeGIFFrameContext238 int dataSize() const { return m_dataSize; } setDataSizeGIFFrameContext239 void setDataSize(int size) 240 { 241 m_dataSize = size; 242 m_isDataSizeDefined = true; 243 } progressiveDisplayGIFFrameContext244 bool progressiveDisplay() const { return m_progressiveDisplay; } setProgressiveDisplayGIFFrameContext245 void setProgressiveDisplay(bool progressiveDisplay) { m_progressiveDisplay = progressiveDisplay; } interlacedGIFFrameContext246 bool interlaced() const { return m_interlaced; } setInterlacedGIFFrameContext247 void setInterlaced(bool interlaced) { m_interlaced = interlaced; } 248 clearDecodeStateGIFFrameContext249 void clearDecodeState() { m_lzwContext.clear(); } localColorMapGIFFrameContext250 const GIFColorMap& localColorMap() const { return m_localColorMap; } localColorMapGIFFrameContext251 GIFColorMap& localColorMap() { return m_localColorMap; } 252 253 private: 254 int m_frameId; 255 unsigned m_xOffset; 256 unsigned m_yOffset; // With respect to "screen" origin. 257 unsigned m_width; 258 unsigned m_height; 259 size_t m_transparentPixel; // Index of transparent pixel. Value is kNotFound if there is no transparent pixel. 260 blink::ImageFrame::DisposalMethod m_disposalMethod; // Restore to background, leave in place, etc. 261 int m_dataSize; 262 263 bool m_progressiveDisplay; // If true, do Haeberli interlace hack. 264 bool m_interlaced; // True, if scanlines arrive interlaced order. 265 266 unsigned m_delayTime; // Display time, in milliseconds, for this image in a multi-image GIF. 267 268 OwnPtr<GIFLZWContext> m_lzwContext; 269 Vector<GIFLZWBlock> m_lzwBlocks; // LZW blocks for this frame. 270 GIFColorMap m_localColorMap; 271 272 size_t m_currentLzwBlock; 273 bool m_isComplete; 274 bool m_isHeaderDefined; 275 bool m_isDataSizeDefined; 276 }; 277 278 class PLATFORM_EXPORT GIFImageReader { 279 WTF_MAKE_FAST_ALLOCATED; WTF_MAKE_NONCOPYABLE(GIFImageReader); 280 public: 281 GIFImageReader(blink::GIFImageDecoder* client = 0) m_client(client)282 : m_client(client) 283 , m_state(GIFType) 284 , m_bytesToConsume(6) // Number of bytes for GIF type, either "GIF87a" or "GIF89a". 285 , m_bytesRead(0) 286 , m_version(0) 287 , m_screenWidth(0) 288 , m_screenHeight(0) 289 , m_loopCount(cLoopCountNotSeen) 290 , m_parseCompleted(false) 291 { 292 } 293 ~GIFImageReader()294 ~GIFImageReader() 295 { 296 } 297 setData(PassRefPtr<blink::SharedBuffer> data)298 void setData(PassRefPtr<blink::SharedBuffer> data) { m_data = data; } 299 bool parse(blink::GIFImageDecoder::GIFParseQuery); 300 bool decode(size_t frameIndex); 301 imagesCount()302 size_t imagesCount() const 303 { 304 if (m_frames.isEmpty()) 305 return 0; 306 307 // This avoids counting an empty frame when the file is truncated right after 308 // GIFControlExtension but before GIFImageHeader. 309 // FIXME: This extra complexity is not necessary and we should just report m_frames.size(). 310 return m_frames.last()->isHeaderDefined() ? m_frames.size() : m_frames.size() - 1; 311 } loopCount()312 int loopCount() const { return m_loopCount; } 313 globalColorMap()314 const GIFColorMap& globalColorMap() const 315 { 316 return m_globalColorMap; 317 } 318 frameContext(size_t index)319 const GIFFrameContext* frameContext(size_t index) const 320 { 321 return index < m_frames.size() ? m_frames[index].get() : 0; 322 } 323 parseCompleted()324 bool parseCompleted() const { return m_parseCompleted; } 325 clearDecodeState(size_t index)326 void clearDecodeState(size_t index) { m_frames[index]->clearDecodeState(); } 327 328 private: 329 bool parseData(size_t dataPosition, size_t len, blink::GIFImageDecoder::GIFParseQuery); 330 void setRemainingBytes(size_t); 331 data(size_t dataPosition)332 const unsigned char* data(size_t dataPosition) const 333 { 334 return reinterpret_cast<const unsigned char*>(m_data->data()) + dataPosition; 335 } 336 337 void addFrameIfNecessary(); currentFrameIsFirstFrame()338 bool currentFrameIsFirstFrame() const 339 { 340 return m_frames.isEmpty() || (m_frames.size() == 1u && !m_frames[0]->isComplete()); 341 } 342 343 blink::GIFImageDecoder* m_client; 344 345 // Parsing state machine. 346 GIFState m_state; // Current decoder master state. 347 size_t m_bytesToConsume; // Number of bytes to consume for next stage of parsing. 348 size_t m_bytesRead; // Number of bytes processed. 349 350 // Global (multi-image) state. 351 int m_version; // Either 89 for GIF89 or 87 for GIF87. 352 unsigned m_screenWidth; // Logical screen width & height. 353 unsigned m_screenHeight; 354 GIFColorMap m_globalColorMap; 355 int m_loopCount; // Netscape specific extension block to control the number of animation loops a GIF renders. 356 357 Vector<OwnPtr<GIFFrameContext> > m_frames; 358 359 RefPtr<blink::SharedBuffer> m_data; 360 bool m_parseCompleted; 361 }; 362 363 #endif 364