scroggo | 19b9153 | 2016-10-24 09:03:26 -0700 | [diff] [blame^] | 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 | class SkGifCodec; |
| 44 | |
| 45 | #include "SkCodec.h" |
| 46 | #include "SkCodecPriv.h" |
| 47 | #include "SkCodecAnimation.h" |
| 48 | #include "SkColorTable.h" |
| 49 | #include "SkData.h" |
| 50 | #include "SkImageInfo.h" |
| 51 | #include "SkStreamBuffer.h" |
| 52 | #include "../private/SkTArray.h" |
| 53 | #include <memory> |
| 54 | #include <vector> |
| 55 | |
| 56 | typedef SkTArray<unsigned char, true> GIFRow; |
| 57 | |
| 58 | |
| 59 | #define MAX_DICTIONARY_ENTRY_BITS 12 |
| 60 | #define MAX_DICTIONARY_ENTRIES 4096 // 2^MAX_DICTIONARY_ENTRY_BITS |
| 61 | #define MAX_COLORS 256 |
| 62 | #define BYTES_PER_COLORMAP_ENTRY 3 |
| 63 | |
| 64 | constexpr int cLoopCountNotSeen = -2; |
| 65 | constexpr size_t kNotFound = static_cast<size_t>(-1); |
| 66 | |
| 67 | // List of possible parsing states. |
| 68 | enum GIFState { |
| 69 | GIFType, |
| 70 | GIFGlobalHeader, |
| 71 | GIFGlobalColormap, |
| 72 | GIFImageStart, |
| 73 | GIFImageHeader, |
| 74 | GIFImageColormap, |
| 75 | GIFImageBody, |
| 76 | GIFLZWStart, |
| 77 | GIFLZW, |
| 78 | GIFSubBlock, |
| 79 | GIFExtension, |
| 80 | GIFControlExtension, |
| 81 | GIFConsumeBlock, |
| 82 | GIFSkipBlock, |
| 83 | GIFDone, |
| 84 | GIFCommentExtension, |
| 85 | GIFApplicationExtension, |
| 86 | GIFNetscapeExtensionBlock, |
| 87 | GIFConsumeNetscapeExtension, |
| 88 | GIFConsumeComment |
| 89 | }; |
| 90 | |
| 91 | struct GIFFrameContext; |
| 92 | |
| 93 | // LZW decoder state machine. |
| 94 | class GIFLZWContext final : public SkNoncopyable { |
| 95 | public: |
| 96 | GIFLZWContext(SkGifCodec* client, const GIFFrameContext* frameContext) |
| 97 | : codesize(0) |
| 98 | , codemask(0) |
| 99 | , clearCode(0) |
| 100 | , avail(0) |
| 101 | , oldcode(0) |
| 102 | , firstchar(0) |
| 103 | , bits(0) |
| 104 | , datum(0) |
| 105 | , ipass(0) |
| 106 | , irow(0) |
| 107 | , rowsRemaining(0) |
| 108 | , rowIter(0) |
| 109 | , m_client(client) |
| 110 | , m_frameContext(frameContext) |
| 111 | { } |
| 112 | |
| 113 | bool prepareToDecode(); |
| 114 | bool outputRow(const unsigned char* rowBegin); |
| 115 | bool doLZW(const unsigned char* block, size_t bytesInBlock); |
| 116 | bool hasRemainingRows() { return rowsRemaining; } |
| 117 | |
| 118 | private: |
| 119 | // LZW decoding states and output states. |
| 120 | int codesize; |
| 121 | int codemask; |
| 122 | int clearCode; // Codeword used to trigger dictionary reset. |
| 123 | int avail; // Index of next available slot in dictionary. |
| 124 | int oldcode; |
| 125 | unsigned char firstchar; |
| 126 | int bits; // Number of unread bits in "datum". |
| 127 | int datum; // 32-bit input buffer. |
| 128 | int ipass; // Interlace pass; Ranges 1-4 if interlaced. |
| 129 | size_t irow; // Current output row, starting at zero. |
| 130 | size_t rowsRemaining; // Rows remaining to be output. |
| 131 | |
| 132 | unsigned short prefix[MAX_DICTIONARY_ENTRIES]; |
| 133 | unsigned char suffix[MAX_DICTIONARY_ENTRIES]; |
| 134 | unsigned short suffixLength[MAX_DICTIONARY_ENTRIES]; |
| 135 | GIFRow rowBuffer; // Single scanline temporary buffer. |
| 136 | unsigned char* rowIter; |
| 137 | |
| 138 | SkGifCodec* const m_client; |
| 139 | const GIFFrameContext* m_frameContext; |
| 140 | }; |
| 141 | |
| 142 | class GIFColorMap final { |
| 143 | public: |
| 144 | GIFColorMap() |
| 145 | : m_isDefined(false) |
| 146 | , m_colors(0) |
| 147 | , m_packColorProc(nullptr) |
| 148 | { |
| 149 | } |
| 150 | |
| 151 | void setNumColors(size_t colors) { |
| 152 | m_colors = colors; |
| 153 | } |
| 154 | |
| 155 | size_t numColors() const { return m_colors; } |
| 156 | |
| 157 | void setRawData(const char* data, size_t size) |
| 158 | { |
| 159 | // FIXME: Can we avoid this copy? |
| 160 | m_rawData = SkData::MakeWithCopy(data, size); |
| 161 | SkASSERT(m_colors * BYTES_PER_COLORMAP_ENTRY == size); |
| 162 | m_isDefined = true; |
| 163 | } |
| 164 | bool isDefined() const { return m_isDefined; } |
| 165 | |
| 166 | // Build RGBA table using the data stream. |
| 167 | sk_sp<SkColorTable> buildTable(SkColorType dstColorType, size_t transparentPixel) const; |
| 168 | |
| 169 | private: |
| 170 | bool m_isDefined; |
| 171 | size_t m_colors; |
| 172 | sk_sp<SkData> m_rawData; |
| 173 | mutable PackColorProc m_packColorProc; |
| 174 | mutable sk_sp<SkColorTable> m_table; |
| 175 | }; |
| 176 | |
| 177 | // LocalFrame output state machine. |
| 178 | struct GIFFrameContext : SkNoncopyable { |
| 179 | public: |
| 180 | GIFFrameContext(int id) |
| 181 | : m_frameId(id) |
| 182 | , m_xOffset(0) |
| 183 | , m_yOffset(0) |
| 184 | , m_width(0) |
| 185 | , m_height(0) |
| 186 | , m_transparentPixel(kNotFound) |
| 187 | , m_disposalMethod(SkCodecAnimation::Keep_DisposalMethod) |
| 188 | , m_requiredFrame(SkCodec::kNone) |
| 189 | , m_dataSize(0) |
| 190 | , m_progressiveDisplay(false) |
| 191 | , m_interlaced(false) |
| 192 | , m_delayTime(0) |
| 193 | , m_currentLzwBlock(0) |
| 194 | , m_isComplete(false) |
| 195 | , m_isHeaderDefined(false) |
| 196 | , m_isDataSizeDefined(false) |
| 197 | { |
| 198 | } |
| 199 | |
| 200 | ~GIFFrameContext() |
| 201 | { |
| 202 | } |
| 203 | |
| 204 | void addLzwBlock(const void* data, size_t size) |
| 205 | { |
| 206 | m_lzwBlocks.push_back(SkData::MakeWithCopy(data, size)); |
| 207 | } |
| 208 | |
| 209 | bool decode(SkGifCodec* client, bool* frameDecoded); |
| 210 | |
| 211 | int frameId() const { return m_frameId; } |
| 212 | void setRect(unsigned x, unsigned y, unsigned width, unsigned height) |
| 213 | { |
| 214 | m_xOffset = x; |
| 215 | m_yOffset = y; |
| 216 | m_width = width; |
| 217 | m_height = height; |
| 218 | } |
| 219 | SkIRect frameRect() const { return SkIRect::MakeXYWH(m_xOffset, m_yOffset, m_width, m_height); } |
| 220 | unsigned xOffset() const { return m_xOffset; } |
| 221 | unsigned yOffset() const { return m_yOffset; } |
| 222 | unsigned width() const { return m_width; } |
| 223 | unsigned height() const { return m_height; } |
| 224 | size_t transparentPixel() const { return m_transparentPixel; } |
| 225 | void setTransparentPixel(size_t pixel) { m_transparentPixel = pixel; } |
| 226 | SkCodecAnimation::DisposalMethod getDisposalMethod() const { return m_disposalMethod; } |
| 227 | void setDisposalMethod(SkCodecAnimation::DisposalMethod disposalMethod) { m_disposalMethod = disposalMethod; } |
| 228 | size_t getRequiredFrame() const { return m_requiredFrame; } |
| 229 | void setRequiredFrame(size_t req) { m_requiredFrame = req; } |
| 230 | unsigned delayTime() const { return m_delayTime; } |
| 231 | void setDelayTime(unsigned delay) { m_delayTime = delay; } |
| 232 | bool isComplete() const { return m_isComplete; } |
| 233 | void setComplete() { m_isComplete = true; } |
| 234 | bool isHeaderDefined() const { return m_isHeaderDefined; } |
| 235 | void setHeaderDefined() { m_isHeaderDefined = true; } |
| 236 | bool isDataSizeDefined() const { return m_isDataSizeDefined; } |
| 237 | int dataSize() const { return m_dataSize; } |
| 238 | void setDataSize(int size) |
| 239 | { |
| 240 | m_dataSize = size; |
| 241 | m_isDataSizeDefined = true; |
| 242 | } |
| 243 | bool progressiveDisplay() const { return m_progressiveDisplay; } |
| 244 | void setProgressiveDisplay(bool progressiveDisplay) { m_progressiveDisplay = progressiveDisplay; } |
| 245 | bool interlaced() const { return m_interlaced; } |
| 246 | void setInterlaced(bool interlaced) { m_interlaced = interlaced; } |
| 247 | |
| 248 | void clearDecodeState() { m_lzwContext.reset(); } |
| 249 | const GIFColorMap& localColorMap() const { return m_localColorMap; } |
| 250 | GIFColorMap& localColorMap() { return m_localColorMap; } |
| 251 | |
| 252 | private: |
| 253 | int m_frameId; |
| 254 | unsigned m_xOffset; |
| 255 | unsigned m_yOffset; // With respect to "screen" origin. |
| 256 | unsigned m_width; |
| 257 | unsigned m_height; |
| 258 | size_t m_transparentPixel; // Index of transparent pixel. Value is kNotFound if there is no transparent pixel. |
| 259 | SkCodecAnimation::DisposalMethod m_disposalMethod; // Restore to background, leave in place, etc. |
| 260 | size_t m_requiredFrame; |
| 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 | std::unique_ptr<GIFLZWContext> m_lzwContext; |
| 269 | std::vector<sk_sp<SkData>> 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 GIFImageReader final : public SkNoncopyable { |
| 279 | public: |
| 280 | // This takes ownership of stream. |
| 281 | GIFImageReader(SkStream* stream) |
| 282 | : m_client(nullptr) |
| 283 | , m_state(GIFType) |
| 284 | , m_bytesToConsume(6) // Number of bytes for GIF type, either "GIF87a" or "GIF89a". |
| 285 | , m_version(0) |
| 286 | , m_screenWidth(0) |
| 287 | , m_screenHeight(0) |
| 288 | , m_loopCount(cLoopCountNotSeen) |
| 289 | , m_streamBuffer(stream) |
| 290 | , m_parseCompleted(false) |
| 291 | , m_firstFrameHasAlpha(false) |
| 292 | , m_firstFrameSupportsIndex8(false) |
| 293 | { |
| 294 | } |
| 295 | |
| 296 | ~GIFImageReader() |
| 297 | { |
| 298 | } |
| 299 | |
| 300 | void setClient(SkGifCodec* client) { m_client = client; } |
| 301 | |
| 302 | unsigned screenWidth() const { return m_screenWidth; } |
| 303 | unsigned screenHeight() const { return m_screenHeight; } |
| 304 | |
| 305 | // Option to pass to parse(). All enums are negative, because a non-negative value is used to |
| 306 | // indicate that the Reader should parse up to and including the frame indicated. |
| 307 | enum GIFParseQuery { |
| 308 | // Parse enough to determine the size. Note that this parses the first frame's header, |
| 309 | // since we may decide to expand based on the frame's dimensions. |
| 310 | GIFSizeQuery = -1, |
| 311 | // Parse to the end, so we know about all frames. |
| 312 | GIFFrameCountQuery = -2, |
| 313 | }; |
| 314 | |
| 315 | // Parse incoming GIF data stream into internal data structures. |
| 316 | // Non-negative values are used to indicate to parse through that frame. |
| 317 | // Return true if parsing has progressed or there is not enough data. |
| 318 | // Return false if a fatal error is encountered. |
| 319 | bool parse(GIFParseQuery); |
| 320 | |
| 321 | // Decode the frame indicated by frameIndex. |
| 322 | // frameComplete will be set to true if the frame is completely decoded. |
| 323 | // The method returns false if there is an error. |
| 324 | bool decode(size_t frameIndex, bool* frameComplete); |
| 325 | |
| 326 | size_t imagesCount() const |
| 327 | { |
| 328 | if (m_frames.empty()) |
| 329 | return 0; |
| 330 | |
| 331 | // This avoids counting an empty frame when the file is truncated right after |
| 332 | // GIFControlExtension but before GIFImageHeader. |
| 333 | // FIXME: This extra complexity is not necessary and we should just report m_frames.size(). |
| 334 | return m_frames.back()->isHeaderDefined() ? m_frames.size() : m_frames.size() - 1; |
| 335 | } |
| 336 | int loopCount() const { return m_loopCount; } |
| 337 | |
| 338 | const GIFColorMap& globalColorMap() const |
| 339 | { |
| 340 | return m_globalColorMap; |
| 341 | } |
| 342 | |
| 343 | const GIFFrameContext* frameContext(size_t index) const |
| 344 | { |
| 345 | return index < m_frames.size() ? m_frames[index].get() : 0; |
| 346 | } |
| 347 | |
| 348 | void clearDecodeState() { |
| 349 | for (size_t index = 0; index < m_frames.size(); index++) { |
| 350 | m_frames[index]->clearDecodeState(); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | // Return the color table for frame index (which may be the global color table). |
| 355 | sk_sp<SkColorTable> getColorTable(SkColorType dstColorType, size_t index) const; |
| 356 | |
| 357 | bool firstFrameHasAlpha() const { return m_firstFrameHasAlpha; } |
| 358 | |
| 359 | bool firstFrameSupportsIndex8() const { return m_firstFrameSupportsIndex8; } |
| 360 | |
| 361 | private: |
| 362 | // Requires that one byte has been buffered into m_streamBuffer. |
| 363 | unsigned char getOneByte() const { |
| 364 | return reinterpret_cast<const unsigned char*>(m_streamBuffer.get())[0]; |
| 365 | } |
| 366 | |
| 367 | void addFrameIfNecessary(); |
| 368 | bool currentFrameIsFirstFrame() const |
| 369 | { |
| 370 | return m_frames.empty() || (m_frames.size() == 1u && !m_frames[0]->isComplete()); |
| 371 | } |
| 372 | |
| 373 | // Unowned pointer |
| 374 | SkGifCodec* m_client; |
| 375 | |
| 376 | // Parsing state machine. |
| 377 | GIFState m_state; // Current decoder master state. |
| 378 | size_t m_bytesToConsume; // Number of bytes to consume for next stage of parsing. |
| 379 | |
| 380 | // Global (multi-image) state. |
| 381 | int m_version; // Either 89 for GIF89 or 87 for GIF87. |
| 382 | unsigned m_screenWidth; // Logical screen width & height. |
| 383 | unsigned m_screenHeight; |
| 384 | GIFColorMap m_globalColorMap; |
| 385 | int m_loopCount; // Netscape specific extension block to control the number of animation loops a GIF renders. |
| 386 | |
| 387 | std::vector<std::unique_ptr<GIFFrameContext>> m_frames; |
| 388 | |
| 389 | SkStreamBuffer m_streamBuffer; |
| 390 | bool m_parseCompleted; |
| 391 | |
| 392 | // These values can be computed before we create a GIFFrameContext, so we |
| 393 | // store them here instead of on m_frames[0]. |
| 394 | bool m_firstFrameHasAlpha; |
| 395 | bool m_firstFrameSupportsIndex8; |
| 396 | }; |
| 397 | |
| 398 | #endif |