blob: f484441c8c3e340d938582eff80c481b538cbf18 [file] [log] [blame]
epoger@google.comec3ed6a2011-07-28 14:26:00 +00001/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
reed@android.com8a1c16f2008-12-17 15:59:43 +00008#include "SkColor.h"
9#include "SkColorPriv.h"
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +000010#include "SkColorTable.h"
11#include "SkImageDecoder.h"
halcanary@google.com29d4e632013-10-11 18:21:56 +000012#include "SkRTConf.h"
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +000013#include "SkScaledBitmapSampler.h"
reed@android.com8a1c16f2008-12-17 15:59:43 +000014#include "SkStream.h"
15#include "SkTemplates.h"
halcanary@google.com29d4e632013-10-11 18:21:56 +000016#include "SkUtils.h"
reed@android.com8a1c16f2008-12-17 15:59:43 +000017
18#include "gif_lib.h"
19
20class SkGIFImageDecoder : public SkImageDecoder {
21public:
commit-bot@chromium.orga936e372013-03-14 14:42:18 +000022 virtual Format getFormat() const SK_OVERRIDE {
reed@android.com8a1c16f2008-12-17 15:59:43 +000023 return kGIF_Format;
24 }
rmistry@google.comd6176b02012-08-23 18:14:13 +000025
reed@android.com8a1c16f2008-12-17 15:59:43 +000026protected:
commit-bot@chromium.orga936e372013-03-14 14:42:18 +000027 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
28
29private:
30 typedef SkImageDecoder INHERITED;
reed@android.com8a1c16f2008-12-17 15:59:43 +000031};
32
33static const uint8_t gStartingIterlaceYValue[] = {
34 0, 4, 2, 1
35};
36static const uint8_t gDeltaIterlaceYValue[] = {
37 8, 8, 4, 2
38};
39
halcanary@google.com29d4e632013-10-11 18:21:56 +000040SK_CONF_DECLARE(bool, c_suppressGIFImageDecoderWarnings,
41 "images.gif.suppressDecoderWarnings", true,
42 "Suppress GIF warnings and errors when calling image decode "
43 "functions.");
44
45
reed@android.com8a1c16f2008-12-17 15:59:43 +000046/* Implement the GIF interlace algorithm in an iterator.
47 1) grab every 8th line beginning at 0
48 2) grab every 8th line beginning at 4
49 3) grab every 4th line beginning at 2
50 4) grab every 2nd line beginning at 1
51*/
52class GifInterlaceIter {
53public:
54 GifInterlaceIter(int height) : fHeight(height) {
55 fStartYPtr = gStartingIterlaceYValue;
56 fDeltaYPtr = gDeltaIterlaceYValue;
57
58 fCurrY = *fStartYPtr++;
59 fDeltaY = *fDeltaYPtr++;
60 }
rmistry@google.comd6176b02012-08-23 18:14:13 +000061
reed@android.com8a1c16f2008-12-17 15:59:43 +000062 int currY() const {
63 SkASSERT(fStartYPtr);
64 SkASSERT(fDeltaYPtr);
65 return fCurrY;
66 }
67
68 void next() {
69 SkASSERT(fStartYPtr);
70 SkASSERT(fDeltaYPtr);
71
72 int y = fCurrY + fDeltaY;
73 // We went from an if statement to a while loop so that we iterate
74 // through fStartYPtr until a valid row is found. This is so that images
75 // that are smaller than 5x5 will not trash memory.
76 while (y >= fHeight) {
77 if (gStartingIterlaceYValue +
78 SK_ARRAY_COUNT(gStartingIterlaceYValue) == fStartYPtr) {
79 // we done
80 SkDEBUGCODE(fStartYPtr = NULL;)
81 SkDEBUGCODE(fDeltaYPtr = NULL;)
82 y = 0;
83 } else {
84 y = *fStartYPtr++;
85 fDeltaY = *fDeltaYPtr++;
86 }
87 }
88 fCurrY = y;
89 }
rmistry@google.comd6176b02012-08-23 18:14:13 +000090
reed@android.com8a1c16f2008-12-17 15:59:43 +000091private:
92 const int fHeight;
93 int fCurrY;
94 int fDeltaY;
95 const uint8_t* fStartYPtr;
96 const uint8_t* fDeltaYPtr;
97};
98
99///////////////////////////////////////////////////////////////////////////////
100
reed@android.com8a1c16f2008-12-17 15:59:43 +0000101static int DecodeCallBackProc(GifFileType* fileType, GifByteType* out,
102 int size) {
103 SkStream* stream = (SkStream*) fileType->UserData;
104 return (int) stream->read(out, size);
105}
106
107void CheckFreeExtension(SavedImage* Image) {
108 if (Image->ExtensionBlocks) {
reed@google.combb896132013-02-01 19:05:48 +0000109#if GIFLIB_MAJOR < 5
reed@android.com8a1c16f2008-12-17 15:59:43 +0000110 FreeExtension(Image);
reed@google.combb896132013-02-01 19:05:48 +0000111#else
112 GifFreeExtensions(&Image->ExtensionBlockCount, &Image->ExtensionBlocks);
113#endif
reed@android.com8a1c16f2008-12-17 15:59:43 +0000114 }
115}
116
117// return NULL on failure
118static const ColorMapObject* find_colormap(const GifFileType* gif) {
119 const ColorMapObject* cmap = gif->Image.ColorMap;
120 if (NULL == cmap) {
121 cmap = gif->SColorMap;
122 }
djsollen@google.com57f49692011-02-23 20:46:31 +0000123
124 if (NULL == cmap) {
125 // no colormap found
126 return NULL;
127 }
reed@android.com8a1c16f2008-12-17 15:59:43 +0000128 // some sanity checks
reed@android.combc7d2fb2010-02-05 15:43:07 +0000129 if (cmap && ((unsigned)cmap->ColorCount > 256 ||
130 cmap->ColorCount != (1 << cmap->BitsPerPixel))) {
reed@android.com8a1c16f2008-12-17 15:59:43 +0000131 cmap = NULL;
132 }
133 return cmap;
134}
135
136// return -1 if not found (i.e. we're completely opaque)
137static int find_transpIndex(const SavedImage& image, int colorCount) {
138 int transpIndex = -1;
139 for (int i = 0; i < image.ExtensionBlockCount; ++i) {
140 const ExtensionBlock* eb = image.ExtensionBlocks + i;
141 if (eb->Function == 0xF9 && eb->ByteCount == 4) {
142 if (eb->Bytes[0] & 1) {
143 transpIndex = (unsigned char)eb->Bytes[3];
144 // check for valid transpIndex
145 if (transpIndex >= colorCount) {
146 transpIndex = -1;
147 }
148 break;
149 }
150 }
151 }
152 return transpIndex;
153}
154
halcanary@google.com29d4e632013-10-11 18:21:56 +0000155static bool error_return(const SkBitmap& bm, const char msg[]) {
156 if (!c_suppressGIFImageDecoderWarnings) {
157 SkDebugf("libgif error [%s] bitmap [%d %d] pixels %p colortable %p\n",
158 msg, bm.width(), bm.height(), bm.getPixels(),
159 bm.getColorTable());
160 }
reed@android.com8a1c16f2008-12-17 15:59:43 +0000161 return false;
162}
halcanary@google.com29d4e632013-10-11 18:21:56 +0000163static void gif_warning(const SkBitmap& bm, const char msg[]) {
164 if (!c_suppressGIFImageDecoderWarnings) {
165 SkDebugf("libgif warning [%s] bitmap [%d %d] pixels %p colortable %p\n",
166 msg, bm.width(), bm.height(), bm.getPixels(),
167 bm.getColorTable());
168 }
169}
reed@android.com8a1c16f2008-12-17 15:59:43 +0000170
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000171/**
172 * Skip rows in the source gif image.
173 * @param gif Source image.
174 * @param dst Scratch output needed by gif library call. Must be >= width bytes.
175 * @param width Bytes per row in the source image.
176 * @param rowsToSkip Number of rows to skip.
177 * @return True on success, false on GIF_ERROR.
178 */
179static bool skip_src_rows(GifFileType* gif, uint8_t* dst, int width, int rowsToSkip) {
180 for (int i = 0; i < rowsToSkip; i++) {
181 if (DGifGetLine(gif, dst, width) == GIF_ERROR) {
182 return false;
183 }
184 }
185 return true;
186}
187
reed@android.com3f1f06a2010-03-03 21:04:12 +0000188bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
reed@google.combb896132013-02-01 19:05:48 +0000189#if GIFLIB_MAJOR < 5
reed@android.com8a1c16f2008-12-17 15:59:43 +0000190 GifFileType* gif = DGifOpen(sk_stream, DecodeCallBackProc);
reed@google.combb896132013-02-01 19:05:48 +0000191#else
192 GifFileType* gif = DGifOpen(sk_stream, DecodeCallBackProc, NULL);
193#endif
reed@android.com8a1c16f2008-12-17 15:59:43 +0000194 if (NULL == gif) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000195 return error_return(*bm, "DGifOpen");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000196 }
197
198 SkAutoTCallIProc<GifFileType, DGifCloseFile> acp(gif);
199
200 SavedImage temp_save;
201 temp_save.ExtensionBlocks=NULL;
202 temp_save.ExtensionBlockCount=0;
203 SkAutoTCallVProc<SavedImage, CheckFreeExtension> acp2(&temp_save);
204
205 int width, height;
206 GifRecordType recType;
207 GifByteType *extData;
reed@google.combb896132013-02-01 19:05:48 +0000208#if GIFLIB_MAJOR >= 5
209 int extFunction;
210#endif
reed@android.com9781ca52009-04-14 14:28:22 +0000211 int transpIndex = -1; // -1 means we don't have it (yet)
halcanary@google.com29d4e632013-10-11 18:21:56 +0000212 int fillIndex = gif->SBackGroundColor;
rmistry@google.comd6176b02012-08-23 18:14:13 +0000213
reed@android.com8a1c16f2008-12-17 15:59:43 +0000214 do {
215 if (DGifGetRecordType(gif, &recType) == GIF_ERROR) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000216 return error_return(*bm, "DGifGetRecordType");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000217 }
rmistry@google.comd6176b02012-08-23 18:14:13 +0000218
reed@android.com8a1c16f2008-12-17 15:59:43 +0000219 switch (recType) {
220 case IMAGE_DESC_RECORD_TYPE: {
221 if (DGifGetImageDesc(gif) == GIF_ERROR) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000222 return error_return(*bm, "IMAGE_DESC_RECORD_TYPE");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000223 }
rmistry@google.comd6176b02012-08-23 18:14:13 +0000224
reed@android.com8a1c16f2008-12-17 15:59:43 +0000225 if (gif->ImageCount < 1) { // sanity check
halcanary@google.com29d4e632013-10-11 18:21:56 +0000226 return error_return(*bm, "ImageCount < 1");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000227 }
rmistry@google.comd6176b02012-08-23 18:14:13 +0000228
reed@android.com8a1c16f2008-12-17 15:59:43 +0000229 width = gif->SWidth;
230 height = gif->SHeight;
halcanary@google.com29d4e632013-10-11 18:21:56 +0000231
232 SavedImage* image = &gif->SavedImages[gif->ImageCount-1];
233 const GifImageDesc& desc = image->ImageDesc;
234
235 int imageLeft = desc.Left;
236 int imageTop = desc.Top;
237 const int innerWidth = desc.Width;
238 const int innerHeight = desc.Height;
239 if (innerWidth <= 0 || innerHeight <= 0) {
240 return error_return(*bm, "invalid dimensions");
241 }
242
243 // check for valid descriptor
244 if (innerWidth > width) {
245 gif_warning(*bm, "image too wide, expanding output to size");
246 width = innerWidth;
247 imageLeft = 0;
248 } else if (imageLeft + innerWidth > width) {
249 gif_warning(*bm, "shifting image left to fit");
250 imageLeft = width - innerWidth;
251 } else if (imageLeft < 0) {
252 gif_warning(*bm, "shifting image right to fit");
253 imageLeft = 0;
254 }
255
256
257 if (innerHeight > height) {
258 gif_warning(*bm, "image too tall, expanding output to size");
259 height = innerHeight;
260 imageTop = 0;
261 } else if (imageTop + innerHeight > height) {
262 gif_warning(*bm, "shifting image up to fit");
263 imageTop = height - innerHeight;
264 } else if (imageTop < 0) {
265 gif_warning(*bm, "shifting image down to fit");
266 imageTop = 0;
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000267 }
268
269 // FIXME: We could give the caller a choice of images or configs.
270 if (!this->chooseFromOneChoice(SkBitmap::kIndex8_Config, width, height)) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000271 return error_return(*bm, "chooseFromOneChoice");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000272 }
skia.committer@gmail.comc49cabf2013-03-15 07:05:19 +0000273
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000274 SkScaledBitmapSampler sampler(width, height, this->getSampleSize());
275
276 bm->setConfig(SkBitmap::kIndex8_Config, sampler.scaledWidth(),
277 sampler.scaledHeight());
278
commit-bot@chromium.orga936e372013-03-14 14:42:18 +0000279 if (SkImageDecoder::kDecodeBounds_Mode == mode) {
commit-bot@chromium.orga936e372013-03-14 14:42:18 +0000280 return true;
281 }
282
rmistry@google.comd6176b02012-08-23 18:14:13 +0000283
reed@android.com8a1c16f2008-12-17 15:59:43 +0000284 // now we decode the colortable
285 int colorCount = 0;
286 {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000287 // Declare colorPtr here for scope.
reed@google.com0a6151d2013-10-10 14:44:56 +0000288 SkPMColor colorPtr[256]; // storage for worst-case
halcanary@google.com29d4e632013-10-11 18:21:56 +0000289 const ColorMapObject* cmap = find_colormap(gif);
reed@google.com0a6151d2013-10-10 14:44:56 +0000290 SkAlphaType alphaType = kOpaque_SkAlphaType;
halcanary@google.com29d4e632013-10-11 18:21:56 +0000291 if (cmap != NULL) {
292 colorCount = cmap->ColorCount;
293 if (colorCount > 256) {
294 colorCount = 256; // our kIndex8 can't support more
295 }
296 for (int index = 0; index < colorCount; index++) {
297 colorPtr[index] = SkPackARGB32(0xFF,
298 cmap->Colors[index].Red,
299 cmap->Colors[index].Green,
300 cmap->Colors[index].Blue);
301 }
302 } else {
303 // find_colormap() returned NULL. Some (rare, broken)
304 // GIFs don't have a color table, so we force one.
305 gif_warning(*bm, "missing colormap");
306 colorCount = 256;
307 sk_memset32(colorPtr, SK_ColorWHITE, colorCount);
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000308 }
reed@android.com9781ca52009-04-14 14:28:22 +0000309 transpIndex = find_transpIndex(temp_save, colorCount);
halcanary@google.com29d4e632013-10-11 18:21:56 +0000310 if (transpIndex >= 0) {
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000311 colorPtr[transpIndex] = SK_ColorTRANSPARENT; // ram in a transparent SkPMColor
reed@google.com0a6151d2013-10-10 14:44:56 +0000312 alphaType = kPremul_SkAlphaType;
halcanary@google.com29d4e632013-10-11 18:21:56 +0000313 fillIndex = transpIndex;
314 } else if (fillIndex >= colorCount) {
315 // gif->SBackGroundColor should be less than colorCount.
316 fillIndex = 0; // If not, fix it.
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000317 }
reed@android.com8a1c16f2008-12-17 15:59:43 +0000318
reed@google.com0a6151d2013-10-10 14:44:56 +0000319 SkAutoTUnref<SkColorTable> ctable(SkNEW_ARGS(SkColorTable,
320 (colorPtr, colorCount,
321 alphaType)));
reed@android.com8a1c16f2008-12-17 15:59:43 +0000322 if (!this->allocPixelRef(bm, ctable)) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000323 return error_return(*bm, "allocPixelRef");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000324 }
325 }
rmistry@google.comd6176b02012-08-23 18:14:13 +0000326
reed@android.com8a1c16f2008-12-17 15:59:43 +0000327 // abort if either inner dimension is <= 0
328 if (innerWidth <= 0 || innerHeight <= 0) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000329 return error_return(*bm, "non-pos inner width/height");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000330 }
331
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000332 SkAutoLockPixels alp(*bm);
333
334 SkAutoMalloc storage(innerWidth);
335 uint8_t* scanline = (uint8_t*) storage.get();
336
337 // GIF has an option to store the scanlines of an image, plus a larger background,
338 // filled by a fill color. In this case, we will use a subset of the larger bitmap
339 // for sampling.
340 SkBitmap subset;
341 SkBitmap* workingBitmap;
reed@android.com8a1c16f2008-12-17 15:59:43 +0000342 // are we only a subset of the total bounds?
halcanary@google.com29d4e632013-10-11 18:21:56 +0000343 if ((imageTop | imageLeft) > 0 ||
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000344 innerWidth < width || innerHeight < height) {
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000345 // Fill the background.
halcanary@google.com29d4e632013-10-11 18:21:56 +0000346 memset(bm->getPixels(), fillIndex, bm->getSize());
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000347
348 // Create a subset of the bitmap.
halcanary@google.com29d4e632013-10-11 18:21:56 +0000349 SkIRect subsetRect(SkIRect::MakeXYWH(imageLeft / sampler.srcDX(),
350 imageTop / sampler.srcDY(),
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000351 innerWidth / sampler.srcDX(),
352 innerHeight / sampler.srcDY()));
353 if (!bm->extractSubset(&subset, subsetRect)) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000354 return error_return(*bm, "Extract failed.");
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000355 }
356 // Update the sampler. We'll now be only sampling into the subset.
357 sampler = SkScaledBitmapSampler(innerWidth, innerHeight, this->getSampleSize());
358 workingBitmap = &subset;
359 } else {
360 workingBitmap = bm;
361 }
362
363 // bm is already locked, but if we had to take a subset, it must be locked also,
364 // so that getPixels() will point to its pixels.
365 SkAutoLockPixels alpWorking(*workingBitmap);
366
367 if (!sampler.begin(workingBitmap, SkScaledBitmapSampler::kIndex, *this)) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000368 return error_return(*bm, "Sampler failed to begin.");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000369 }
rmistry@google.comd6176b02012-08-23 18:14:13 +0000370
reed@android.com8a1c16f2008-12-17 15:59:43 +0000371 // now decode each scanline
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000372 if (gif->Image.Interlace) {
373 // Iterate over the height of the source data. The sampler will
374 // take care of skipping unneeded rows.
reed@android.com8a1c16f2008-12-17 15:59:43 +0000375 GifInterlaceIter iter(innerHeight);
halcanary@google.com29d4e632013-10-11 18:21:56 +0000376 for (int y = 0; y < innerHeight; y++) {
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000377 if (DGifGetLine(gif, scanline, innerWidth) == GIF_ERROR) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000378 gif_warning(*bm, "interlace DGifGetLine");
379 memset(scanline, fillIndex, innerWidth);
380 for (; y < innerHeight; y++) {
381 sampler.sampleInterlaced(scanline, iter.currY());
382 iter.next();
383 }
384 return true;
reed@android.com8a1c16f2008-12-17 15:59:43 +0000385 }
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000386 sampler.sampleInterlaced(scanline, iter.currY());
reed@android.com8a1c16f2008-12-17 15:59:43 +0000387 iter.next();
388 }
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000389 } else {
reed@android.com8a1c16f2008-12-17 15:59:43 +0000390 // easy, non-interlace case
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000391 const int outHeight = workingBitmap->height();
392 skip_src_rows(gif, scanline, innerWidth, sampler.srcY0());
393 for (int y = 0; y < outHeight; y++) {
reed@android.com8a1c16f2008-12-17 15:59:43 +0000394 if (DGifGetLine(gif, scanline, innerWidth) == GIF_ERROR) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000395 gif_warning(*bm, "DGifGetLine");
396 memset(scanline, fillIndex, innerWidth);
397 for (; y < outHeight; y++) {
398 sampler.next(scanline);
399 }
400 return true;
reed@android.com8a1c16f2008-12-17 15:59:43 +0000401 }
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000402 // scanline now contains the raw data. Sample it.
403 sampler.next(scanline);
404 if (y < outHeight - 1) {
405 skip_src_rows(gif, scanline, innerWidth, sampler.srcDY() - 1);
406 }
reed@android.com8a1c16f2008-12-17 15:59:43 +0000407 }
commit-bot@chromium.orgdac4a1d2013-10-08 19:40:18 +0000408 // skip the rest of the rows (if any)
409 int read = (outHeight - 1) * sampler.srcDY() + sampler.srcY0() + 1;
410 SkASSERT(read <= innerHeight);
411 skip_src_rows(gif, scanline, innerWidth, innerHeight - read);
reed@android.com8a1c16f2008-12-17 15:59:43 +0000412 }
halcanary@google.com29d4e632013-10-11 18:21:56 +0000413 return true;
reed@android.com8a1c16f2008-12-17 15:59:43 +0000414 } break;
rmistry@google.comd6176b02012-08-23 18:14:13 +0000415
reed@android.com8a1c16f2008-12-17 15:59:43 +0000416 case EXTENSION_RECORD_TYPE:
reed@google.combb896132013-02-01 19:05:48 +0000417#if GIFLIB_MAJOR < 5
reed@android.com8a1c16f2008-12-17 15:59:43 +0000418 if (DGifGetExtension(gif, &temp_save.Function,
419 &extData) == GIF_ERROR) {
reed@google.combb896132013-02-01 19:05:48 +0000420#else
421 if (DGifGetExtension(gif, &extFunction, &extData) == GIF_ERROR) {
422#endif
halcanary@google.com29d4e632013-10-11 18:21:56 +0000423 return error_return(*bm, "DGifGetExtension");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000424 }
425
426 while (extData != NULL) {
427 /* Create an extension block with our data */
reed@google.combb896132013-02-01 19:05:48 +0000428#if GIFLIB_MAJOR < 5
reed@android.com8a1c16f2008-12-17 15:59:43 +0000429 if (AddExtensionBlock(&temp_save, extData[0],
430 &extData[1]) == GIF_ERROR) {
reed@google.combb896132013-02-01 19:05:48 +0000431#else
432 if (GifAddExtensionBlock(&gif->ExtensionBlockCount,
433 &gif->ExtensionBlocks,
434 extFunction,
435 extData[0],
436 &extData[1]) == GIF_ERROR) {
437#endif
halcanary@google.com29d4e632013-10-11 18:21:56 +0000438 return error_return(*bm, "AddExtensionBlock");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000439 }
440 if (DGifGetExtensionNext(gif, &extData) == GIF_ERROR) {
halcanary@google.com29d4e632013-10-11 18:21:56 +0000441 return error_return(*bm, "DGifGetExtensionNext");
reed@android.com8a1c16f2008-12-17 15:59:43 +0000442 }
reed@google.combb896132013-02-01 19:05:48 +0000443#if GIFLIB_MAJOR < 5
reed@android.com8a1c16f2008-12-17 15:59:43 +0000444 temp_save.Function = 0;
reed@google.combb896132013-02-01 19:05:48 +0000445#endif
reed@android.com8a1c16f2008-12-17 15:59:43 +0000446 }
447 break;
rmistry@google.comd6176b02012-08-23 18:14:13 +0000448
reed@android.com8a1c16f2008-12-17 15:59:43 +0000449 case TERMINATE_RECORD_TYPE:
450 break;
rmistry@google.comd6176b02012-08-23 18:14:13 +0000451
452 default: /* Should be trapped by DGifGetRecordType */
reed@android.com8a1c16f2008-12-17 15:59:43 +0000453 break;
454 }
455 } while (recType != TERMINATE_RECORD_TYPE);
456
reed@android.com8a1c16f2008-12-17 15:59:43 +0000457 return true;
458}
459
460///////////////////////////////////////////////////////////////////////////////
robertphillips@google.comec51cb82012-03-23 18:13:47 +0000461DEFINE_DECODER_CREATOR(GIFImageDecoder);
462///////////////////////////////////////////////////////////////////////////////
reed@android.com8a1c16f2008-12-17 15:59:43 +0000463
scroggo@google.comb5571b32013-09-25 21:34:24 +0000464static bool is_gif(SkStreamRewindable* stream) {
reed@android.com8a1c16f2008-12-17 15:59:43 +0000465 char buf[GIF_STAMP_LEN];
466 if (stream->read(buf, GIF_STAMP_LEN) == GIF_STAMP_LEN) {
467 if (memcmp(GIF_STAMP, buf, GIF_STAMP_LEN) == 0 ||
468 memcmp(GIF87_STAMP, buf, GIF_STAMP_LEN) == 0 ||
469 memcmp(GIF89_STAMP, buf, GIF_STAMP_LEN) == 0) {
scroggo@google.com39edf4c2013-04-25 17:33:51 +0000470 return true;
reed@android.com8a1c16f2008-12-17 15:59:43 +0000471 }
472 }
scroggo@google.com39edf4c2013-04-25 17:33:51 +0000473 return false;
474}
475
scroggo@google.comb5571b32013-09-25 21:34:24 +0000476static SkImageDecoder* sk_libgif_dfactory(SkStreamRewindable* stream) {
scroggo@google.com39edf4c2013-04-25 17:33:51 +0000477 if (is_gif(stream)) {
478 return SkNEW(SkGIFImageDecoder);
479 }
reed@android.com8a1c16f2008-12-17 15:59:43 +0000480 return NULL;
481}
482
mtklein@google.combd6343b2013-09-04 17:20:18 +0000483static SkImageDecoder_DecodeReg gReg(sk_libgif_dfactory);
scroggo@google.com39edf4c2013-04-25 17:33:51 +0000484
scroggo@google.comb5571b32013-09-25 21:34:24 +0000485static SkImageDecoder::Format get_format_gif(SkStreamRewindable* stream) {
scroggo@google.com39edf4c2013-04-25 17:33:51 +0000486 if (is_gif(stream)) {
487 return SkImageDecoder::kGIF_Format;
488 }
489 return SkImageDecoder::kUnknown_Format;
490}
491
mtklein@google.combd6343b2013-09-04 17:20:18 +0000492static SkImageDecoder_FormatReg gFormatReg(get_format_gif);