1 | // Copyright 2012 Google Inc. All Rights Reserved. |
2 | // |
3 | // Use of this source code is governed by a BSD-style license |
4 | // that can be found in the COPYING file in the root of the source |
5 | // tree. An additional intellectual property rights grant can be found |
6 | // in the file PATENTS. All contributing project authors may |
7 | // be found in the AUTHORS file in the root of the source tree. |
8 | // ----------------------------------------------------------------------------- |
9 | // |
10 | // WebP container demux. |
11 | // |
12 | |
13 | #ifdef HAVE_CONFIG_H |
14 | #include "../webp/config.h" |
15 | #endif |
16 | |
17 | #include <assert.h> |
18 | #include <stdlib.h> |
19 | #include <string.h> |
20 | |
21 | #include "../utils/utils.h" |
22 | #include "../webp/decode.h" // WebPGetFeatures |
23 | #include "../webp/demux.h" |
24 | #include "../webp/format_constants.h" |
25 | |
26 | #define DMUX_MAJ_VERSION 0 |
27 | #define DMUX_MIN_VERSION 3 |
28 | #define DMUX_REV_VERSION 2 |
29 | |
30 | typedef struct { |
31 | size_t start_; // start location of the data |
32 | size_t end_; // end location |
33 | size_t riff_end_; // riff chunk end location, can be > end_. |
34 | size_t buf_size_; // size of the buffer |
35 | const uint8_t* buf_; |
36 | } MemBuffer; |
37 | |
38 | typedef struct { |
39 | size_t offset_; |
40 | size_t size_; |
41 | } ChunkData; |
42 | |
43 | typedef struct Frame { |
44 | int x_offset_, y_offset_; |
45 | int width_, height_; |
46 | int has_alpha_; |
47 | int duration_; |
48 | WebPMuxAnimDispose dispose_method_; |
49 | WebPMuxAnimBlend blend_method_; |
50 | int frame_num_; |
51 | int complete_; // img_components_ contains a full image. |
52 | ChunkData img_components_[2]; // 0=VP8{,L} 1=ALPH |
53 | struct Frame* next_; |
54 | } Frame; |
55 | |
56 | typedef struct Chunk { |
57 | ChunkData data_; |
58 | struct Chunk* next_; |
59 | } Chunk; |
60 | |
61 | struct WebPDemuxer { |
62 | MemBuffer mem_; |
63 | WebPDemuxState state_; |
64 | int is_ext_format_; |
65 | uint32_t feature_flags_; |
66 | int canvas_width_, canvas_height_; |
67 | int loop_count_; |
68 | uint32_t bgcolor_; |
69 | int num_frames_; |
70 | Frame* frames_; |
71 | Frame** frames_tail_; |
72 | Chunk* chunks_; // non-image chunks |
73 | Chunk** chunks_tail_; |
74 | }; |
75 | |
76 | typedef enum { |
77 | PARSE_OK, |
78 | PARSE_NEED_MORE_DATA, |
79 | PARSE_ERROR |
80 | } ParseStatus; |
81 | |
82 | typedef struct ChunkParser { |
83 | uint8_t id[4]; |
84 | ParseStatus (*parse)(WebPDemuxer* const dmux); |
85 | int (*valid)(const WebPDemuxer* const dmux); |
86 | } ChunkParser; |
87 | |
88 | static ParseStatus ParseSingleImage(WebPDemuxer* const dmux); |
89 | static ParseStatus ParseVP8X(WebPDemuxer* const dmux); |
90 | static int IsValidSimpleFormat(const WebPDemuxer* const dmux); |
91 | static int IsValidExtendedFormat(const WebPDemuxer* const dmux); |
92 | |
93 | static const ChunkParser kMasterChunks[] = { |
94 | { { 'V', 'P', '8', ' ' }, ParseSingleImage, IsValidSimpleFormat }, |
95 | { { 'V', 'P', '8', 'L' }, ParseSingleImage, IsValidSimpleFormat }, |
96 | { { 'V', 'P', '8', 'X' }, ParseVP8X, IsValidExtendedFormat }, |
97 | { { '0', '0', '0', '0' }, NULL, NULL }, |
98 | }; |
99 | |
100 | //------------------------------------------------------------------------------ |
101 | |
102 | int WebPGetDemuxVersion(void) { |
103 | return (DMUX_MAJ_VERSION << 16) | (DMUX_MIN_VERSION << 8) | DMUX_REV_VERSION; |
104 | } |
105 | |
106 | // ----------------------------------------------------------------------------- |
107 | // MemBuffer |
108 | |
109 | static int RemapMemBuffer(MemBuffer* const mem, |
110 | const uint8_t* data, size_t size) { |
111 | if (size < mem->buf_size_) return 0; // can't remap to a shorter buffer! |
112 | |
113 | mem->buf_ = data; |
114 | mem->end_ = mem->buf_size_ = size; |
115 | return 1; |
116 | } |
117 | |
118 | static int InitMemBuffer(MemBuffer* const mem, |
119 | const uint8_t* data, size_t size) { |
120 | memset(mem, 0, sizeof(*mem)); |
121 | return RemapMemBuffer(mem, data, size); |
122 | } |
123 | |
124 | // Return the remaining data size available in 'mem'. |
125 | static WEBP_INLINE size_t MemDataSize(const MemBuffer* const mem) { |
126 | return (mem->end_ - mem->start_); |
127 | } |
128 | |
129 | // Return true if 'size' exceeds the end of the RIFF chunk. |
130 | static WEBP_INLINE int SizeIsInvalid(const MemBuffer* const mem, size_t size) { |
131 | return (size > mem->riff_end_ - mem->start_); |
132 | } |
133 | |
134 | static WEBP_INLINE void Skip(MemBuffer* const mem, size_t size) { |
135 | mem->start_ += size; |
136 | } |
137 | |
138 | static WEBP_INLINE void Rewind(MemBuffer* const mem, size_t size) { |
139 | mem->start_ -= size; |
140 | } |
141 | |
142 | static WEBP_INLINE const uint8_t* GetBuffer(MemBuffer* const mem) { |
143 | return mem->buf_ + mem->start_; |
144 | } |
145 | |
146 | // Read from 'mem' and skip the read bytes. |
147 | static WEBP_INLINE uint8_t ReadByte(MemBuffer* const mem) { |
148 | const uint8_t byte = mem->buf_[mem->start_]; |
149 | Skip(mem, 1); |
150 | return byte; |
151 | } |
152 | |
153 | static WEBP_INLINE int ReadLE16s(MemBuffer* const mem) { |
154 | const uint8_t* const data = mem->buf_ + mem->start_; |
155 | const int val = GetLE16(data); |
156 | Skip(mem, 2); |
157 | return val; |
158 | } |
159 | |
160 | static WEBP_INLINE int ReadLE24s(MemBuffer* const mem) { |
161 | const uint8_t* const data = mem->buf_ + mem->start_; |
162 | const int val = GetLE24(data); |
163 | Skip(mem, 3); |
164 | return val; |
165 | } |
166 | |
167 | static WEBP_INLINE uint32_t ReadLE32(MemBuffer* const mem) { |
168 | const uint8_t* const data = mem->buf_ + mem->start_; |
169 | const uint32_t val = GetLE32(data); |
170 | Skip(mem, 4); |
171 | return val; |
172 | } |
173 | |
174 | // ----------------------------------------------------------------------------- |
175 | // Secondary chunk parsing |
176 | |
177 | static void AddChunk(WebPDemuxer* const dmux, Chunk* const chunk) { |
178 | *dmux->chunks_tail_ = chunk; |
179 | chunk->next_ = NULL; |
180 | dmux->chunks_tail_ = &chunk->next_; |
181 | } |
182 | |
183 | // Add a frame to the end of the list, ensuring the last frame is complete. |
184 | // Returns true on success, false otherwise. |
185 | static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) { |
186 | const Frame* const last_frame = *dmux->frames_tail_; |
187 | if (last_frame != NULL && !last_frame->complete_) return 0; |
188 | |
189 | *dmux->frames_tail_ = frame; |
190 | frame->next_ = NULL; |
191 | dmux->frames_tail_ = &frame->next_; |
192 | return 1; |
193 | } |
194 | |
195 | static void SetFrameInfo(size_t start_offset, size_t size, |
196 | int frame_num, int complete, |
197 | const WebPBitstreamFeatures* const features, |
198 | Frame* const frame) { |
199 | frame->img_components_[0].offset_ = start_offset; |
200 | frame->img_components_[0].size_ = size; |
201 | frame->width_ = features->width; |
202 | frame->height_ = features->height; |
203 | frame->has_alpha_ |= features->has_alpha; |
204 | frame->frame_num_ = frame_num; |
205 | frame->complete_ = complete; |
206 | } |
207 | |
208 | // Store image bearing chunks to 'frame'. |
209 | static ParseStatus StoreFrame(int frame_num, uint32_t min_size, |
210 | MemBuffer* const mem, Frame* const frame) { |
211 | int alpha_chunks = 0; |
212 | int image_chunks = 0; |
213 | int done = (MemDataSize(mem) < min_size); |
214 | ParseStatus status = PARSE_OK; |
215 | |
216 | if (done) return PARSE_NEED_MORE_DATA; |
217 | |
218 | do { |
219 | const size_t chunk_start_offset = mem->start_; |
220 | const uint32_t fourcc = ReadLE32(mem); |
221 | const uint32_t payload_size = ReadLE32(mem); |
222 | const uint32_t payload_size_padded = payload_size + (payload_size & 1); |
223 | const size_t payload_available = (payload_size_padded > MemDataSize(mem)) |
224 | ? MemDataSize(mem) : payload_size_padded; |
225 | const size_t chunk_size = CHUNK_HEADER_SIZE + payload_available; |
226 | |
227 | if (payload_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
228 | if (SizeIsInvalid(mem, payload_size_padded)) return PARSE_ERROR; |
229 | if (payload_size_padded > MemDataSize(mem)) status = PARSE_NEED_MORE_DATA; |
230 | |
231 | switch (fourcc) { |
232 | case MKFOURCC('A', 'L', 'P', 'H'): |
233 | if (alpha_chunks == 0) { |
234 | ++alpha_chunks; |
235 | frame->img_components_[1].offset_ = chunk_start_offset; |
236 | frame->img_components_[1].size_ = chunk_size; |
237 | frame->has_alpha_ = 1; |
238 | frame->frame_num_ = frame_num; |
239 | Skip(mem, payload_available); |
240 | } else { |
241 | goto Done; |
242 | } |
243 | break; |
244 | case MKFOURCC('V', 'P', '8', 'L'): |
245 | if (alpha_chunks > 0) return PARSE_ERROR; // VP8L has its own alpha |
246 | // fall through |
247 | case MKFOURCC('V', 'P', '8', ' '): |
248 | if (image_chunks == 0) { |
249 | // Extract the bitstream features, tolerating failures when the data |
250 | // is incomplete. |
251 | WebPBitstreamFeatures features; |
252 | const VP8StatusCode vp8_status = |
253 | WebPGetFeatures(mem->buf_ + chunk_start_offset, chunk_size, |
254 | &features); |
255 | if (status == PARSE_NEED_MORE_DATA && |
256 | vp8_status == VP8_STATUS_NOT_ENOUGH_DATA) { |
257 | return PARSE_NEED_MORE_DATA; |
258 | } else if (vp8_status != VP8_STATUS_OK) { |
259 | // We have enough data, and yet WebPGetFeatures() failed. |
260 | return PARSE_ERROR; |
261 | } |
262 | ++image_chunks; |
263 | SetFrameInfo(chunk_start_offset, chunk_size, frame_num, |
264 | status == PARSE_OK, &features, frame); |
265 | Skip(mem, payload_available); |
266 | } else { |
267 | goto Done; |
268 | } |
269 | break; |
270 | Done: |
271 | default: |
272 | // Restore fourcc/size when moving up one level in parsing. |
273 | Rewind(mem, CHUNK_HEADER_SIZE); |
274 | done = 1; |
275 | break; |
276 | } |
277 | |
278 | if (mem->start_ == mem->riff_end_) { |
279 | done = 1; |
280 | } else if (MemDataSize(mem) < CHUNK_HEADER_SIZE) { |
281 | status = PARSE_NEED_MORE_DATA; |
282 | } |
283 | } while (!done && status == PARSE_OK); |
284 | |
285 | return status; |
286 | } |
287 | |
288 | // Creates a new Frame if 'actual_size' is within bounds and 'mem' contains |
289 | // enough data ('min_size') to parse the payload. |
290 | // Returns PARSE_OK on success with *frame pointing to the new Frame. |
291 | // Returns PARSE_NEED_MORE_DATA with insufficient data, PARSE_ERROR otherwise. |
292 | static ParseStatus NewFrame(const MemBuffer* const mem, |
293 | uint32_t min_size, uint32_t actual_size, |
294 | Frame** frame) { |
295 | if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR; |
296 | if (actual_size < min_size) return PARSE_ERROR; |
297 | if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
298 | |
299 | *frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(**frame)); |
300 | return (*frame == NULL) ? PARSE_ERROR : PARSE_OK; |
301 | } |
302 | |
303 | // Parse a 'ANMF' chunk and any image bearing chunks that immediately follow. |
304 | // 'frame_chunk_size' is the previously validated, padded chunk size. |
305 | static ParseStatus ParseAnimationFrame( |
306 | WebPDemuxer* const dmux, uint32_t frame_chunk_size) { |
307 | const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
308 | const uint32_t anmf_payload_size = frame_chunk_size - ANMF_CHUNK_SIZE; |
309 | int added_frame = 0; |
310 | int bits; |
311 | MemBuffer* const mem = &dmux->mem_; |
312 | Frame* frame; |
313 | ParseStatus status = |
314 | NewFrame(mem, ANMF_CHUNK_SIZE, frame_chunk_size, &frame); |
315 | if (status != PARSE_OK) return status; |
316 | |
317 | frame->x_offset_ = 2 * ReadLE24s(mem); |
318 | frame->y_offset_ = 2 * ReadLE24s(mem); |
319 | frame->width_ = 1 + ReadLE24s(mem); |
320 | frame->height_ = 1 + ReadLE24s(mem); |
321 | frame->duration_ = ReadLE24s(mem); |
322 | bits = ReadByte(mem); |
323 | frame->dispose_method_ = |
324 | (bits & 1) ? WEBP_MUX_DISPOSE_BACKGROUND : WEBP_MUX_DISPOSE_NONE; |
325 | frame->blend_method_ = (bits & 2) ? WEBP_MUX_NO_BLEND : WEBP_MUX_BLEND; |
326 | if (frame->width_ * (uint64_t)frame->height_ >= MAX_IMAGE_AREA) { |
327 | WebPSafeFree(frame); |
328 | return PARSE_ERROR; |
329 | } |
330 | |
331 | // Store a frame only if the animation flag is set there is some data for |
332 | // this frame is available. |
333 | status = StoreFrame(dmux->num_frames_ + 1, anmf_payload_size, mem, frame); |
334 | if (status != PARSE_ERROR && is_animation && frame->frame_num_ > 0) { |
335 | added_frame = AddFrame(dmux, frame); |
336 | if (added_frame) { |
337 | ++dmux->num_frames_; |
338 | } else { |
339 | status = PARSE_ERROR; |
340 | } |
341 | } |
342 | |
343 | if (!added_frame) WebPSafeFree(frame); |
344 | return status; |
345 | } |
346 | |
347 | // General chunk storage, starting with the header at 'start_offset', allowing |
348 | // the user to request the payload via a fourcc string. 'size' includes the |
349 | // header and the unpadded payload size. |
350 | // Returns true on success, false otherwise. |
351 | static int StoreChunk(WebPDemuxer* const dmux, |
352 | size_t start_offset, uint32_t size) { |
353 | Chunk* const chunk = (Chunk*)WebPSafeCalloc(1ULL, sizeof(*chunk)); |
354 | if (chunk == NULL) return 0; |
355 | |
356 | chunk->data_.offset_ = start_offset; |
357 | chunk->data_.size_ = size; |
358 | AddChunk(dmux, chunk); |
359 | return 1; |
360 | } |
361 | |
362 | // ----------------------------------------------------------------------------- |
363 | // Primary chunk parsing |
364 | |
365 | static ParseStatus (MemBuffer* const mem) { |
366 | const size_t min_size = RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE; |
367 | uint32_t riff_size; |
368 | |
369 | // Basic file level validation. |
370 | if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
371 | if (memcmp(GetBuffer(mem), "RIFF" , CHUNK_SIZE_BYTES) || |
372 | memcmp(GetBuffer(mem) + CHUNK_HEADER_SIZE, "WEBP" , CHUNK_SIZE_BYTES)) { |
373 | return PARSE_ERROR; |
374 | } |
375 | |
376 | riff_size = GetLE32(GetBuffer(mem) + TAG_SIZE); |
377 | if (riff_size < CHUNK_HEADER_SIZE) return PARSE_ERROR; |
378 | if (riff_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
379 | |
380 | // There's no point in reading past the end of the RIFF chunk |
381 | mem->riff_end_ = riff_size + CHUNK_HEADER_SIZE; |
382 | if (mem->buf_size_ > mem->riff_end_) { |
383 | mem->buf_size_ = mem->end_ = mem->riff_end_; |
384 | } |
385 | |
386 | Skip(mem, RIFF_HEADER_SIZE); |
387 | return PARSE_OK; |
388 | } |
389 | |
390 | static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) { |
391 | const size_t min_size = CHUNK_HEADER_SIZE; |
392 | MemBuffer* const mem = &dmux->mem_; |
393 | Frame* frame; |
394 | ParseStatus status; |
395 | int image_added = 0; |
396 | |
397 | if (dmux->frames_ != NULL) return PARSE_ERROR; |
398 | if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR; |
399 | if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
400 | |
401 | frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(*frame)); |
402 | if (frame == NULL) return PARSE_ERROR; |
403 | |
404 | // For the single image case we allow parsing of a partial frame, but we need |
405 | // at least CHUNK_HEADER_SIZE for parsing. |
406 | status = StoreFrame(1, CHUNK_HEADER_SIZE, &dmux->mem_, frame); |
407 | if (status != PARSE_ERROR) { |
408 | const int has_alpha = !!(dmux->feature_flags_ & ALPHA_FLAG); |
409 | // Clear any alpha when the alpha flag is missing. |
410 | if (!has_alpha && frame->img_components_[1].size_ > 0) { |
411 | frame->img_components_[1].offset_ = 0; |
412 | frame->img_components_[1].size_ = 0; |
413 | frame->has_alpha_ = 0; |
414 | } |
415 | |
416 | // Use the frame width/height as the canvas values for non-vp8x files. |
417 | // Also, set ALPHA_FLAG if this is a lossless image with alpha. |
418 | if (!dmux->is_ext_format_ && frame->width_ > 0 && frame->height_ > 0) { |
419 | dmux->state_ = WEBP_DEMUX_PARSED_HEADER; |
420 | dmux->canvas_width_ = frame->width_; |
421 | dmux->canvas_height_ = frame->height_; |
422 | dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0; |
423 | } |
424 | if (!AddFrame(dmux, frame)) { |
425 | status = PARSE_ERROR; // last frame was left incomplete |
426 | } else { |
427 | image_added = 1; |
428 | dmux->num_frames_ = 1; |
429 | } |
430 | } |
431 | |
432 | if (!image_added) WebPSafeFree(frame); |
433 | return status; |
434 | } |
435 | |
436 | static ParseStatus ParseVP8XChunks(WebPDemuxer* const dmux) { |
437 | const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
438 | MemBuffer* const mem = &dmux->mem_; |
439 | int anim_chunks = 0; |
440 | ParseStatus status = PARSE_OK; |
441 | |
442 | do { |
443 | int store_chunk = 1; |
444 | const size_t chunk_start_offset = mem->start_; |
445 | const uint32_t fourcc = ReadLE32(mem); |
446 | const uint32_t chunk_size = ReadLE32(mem); |
447 | const uint32_t chunk_size_padded = chunk_size + (chunk_size & 1); |
448 | |
449 | if (chunk_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
450 | if (SizeIsInvalid(mem, chunk_size_padded)) return PARSE_ERROR; |
451 | |
452 | switch (fourcc) { |
453 | case MKFOURCC('V', 'P', '8', 'X'): { |
454 | return PARSE_ERROR; |
455 | } |
456 | case MKFOURCC('A', 'L', 'P', 'H'): |
457 | case MKFOURCC('V', 'P', '8', ' '): |
458 | case MKFOURCC('V', 'P', '8', 'L'): { |
459 | // check that this isn't an animation (all frames should be in an ANMF). |
460 | if (anim_chunks > 0 || is_animation) return PARSE_ERROR; |
461 | |
462 | Rewind(mem, CHUNK_HEADER_SIZE); |
463 | status = ParseSingleImage(dmux); |
464 | break; |
465 | } |
466 | case MKFOURCC('A', 'N', 'I', 'M'): { |
467 | if (chunk_size_padded < ANIM_CHUNK_SIZE) return PARSE_ERROR; |
468 | |
469 | if (MemDataSize(mem) < chunk_size_padded) { |
470 | status = PARSE_NEED_MORE_DATA; |
471 | } else if (anim_chunks == 0) { |
472 | ++anim_chunks; |
473 | dmux->bgcolor_ = ReadLE32(mem); |
474 | dmux->loop_count_ = ReadLE16s(mem); |
475 | Skip(mem, chunk_size_padded - ANIM_CHUNK_SIZE); |
476 | } else { |
477 | store_chunk = 0; |
478 | goto Skip; |
479 | } |
480 | break; |
481 | } |
482 | case MKFOURCC('A', 'N', 'M', 'F'): { |
483 | if (anim_chunks == 0) return PARSE_ERROR; // 'ANIM' precedes frames. |
484 | status = ParseAnimationFrame(dmux, chunk_size_padded); |
485 | break; |
486 | } |
487 | case MKFOURCC('I', 'C', 'C', 'P'): { |
488 | store_chunk = !!(dmux->feature_flags_ & ICCP_FLAG); |
489 | goto Skip; |
490 | } |
491 | case MKFOURCC('E', 'X', 'I', 'F'): { |
492 | store_chunk = !!(dmux->feature_flags_ & EXIF_FLAG); |
493 | goto Skip; |
494 | } |
495 | case MKFOURCC('X', 'M', 'P', ' '): { |
496 | store_chunk = !!(dmux->feature_flags_ & XMP_FLAG); |
497 | goto Skip; |
498 | } |
499 | Skip: |
500 | default: { |
501 | if (chunk_size_padded <= MemDataSize(mem)) { |
502 | if (store_chunk) { |
503 | // Store only the chunk header and unpadded size as only the payload |
504 | // will be returned to the user. |
505 | if (!StoreChunk(dmux, chunk_start_offset, |
506 | CHUNK_HEADER_SIZE + chunk_size)) { |
507 | return PARSE_ERROR; |
508 | } |
509 | } |
510 | Skip(mem, chunk_size_padded); |
511 | } else { |
512 | status = PARSE_NEED_MORE_DATA; |
513 | } |
514 | } |
515 | } |
516 | |
517 | if (mem->start_ == mem->riff_end_) { |
518 | break; |
519 | } else if (MemDataSize(mem) < CHUNK_HEADER_SIZE) { |
520 | status = PARSE_NEED_MORE_DATA; |
521 | } |
522 | } while (status == PARSE_OK); |
523 | |
524 | return status; |
525 | } |
526 | |
527 | static ParseStatus ParseVP8X(WebPDemuxer* const dmux) { |
528 | MemBuffer* const mem = &dmux->mem_; |
529 | uint32_t vp8x_size; |
530 | |
531 | if (MemDataSize(mem) < CHUNK_HEADER_SIZE) return PARSE_NEED_MORE_DATA; |
532 | |
533 | dmux->is_ext_format_ = 1; |
534 | Skip(mem, TAG_SIZE); // VP8X |
535 | vp8x_size = ReadLE32(mem); |
536 | if (vp8x_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
537 | if (vp8x_size < VP8X_CHUNK_SIZE) return PARSE_ERROR; |
538 | vp8x_size += vp8x_size & 1; |
539 | if (SizeIsInvalid(mem, vp8x_size)) return PARSE_ERROR; |
540 | if (MemDataSize(mem) < vp8x_size) return PARSE_NEED_MORE_DATA; |
541 | |
542 | dmux->feature_flags_ = ReadByte(mem); |
543 | Skip(mem, 3); // Reserved. |
544 | dmux->canvas_width_ = 1 + ReadLE24s(mem); |
545 | dmux->canvas_height_ = 1 + ReadLE24s(mem); |
546 | if (dmux->canvas_width_ * (uint64_t)dmux->canvas_height_ >= MAX_IMAGE_AREA) { |
547 | return PARSE_ERROR; // image final dimension is too large |
548 | } |
549 | Skip(mem, vp8x_size - VP8X_CHUNK_SIZE); // skip any trailing data. |
550 | dmux->state_ = WEBP_DEMUX_PARSED_HEADER; |
551 | |
552 | if (SizeIsInvalid(mem, CHUNK_HEADER_SIZE)) return PARSE_ERROR; |
553 | if (MemDataSize(mem) < CHUNK_HEADER_SIZE) return PARSE_NEED_MORE_DATA; |
554 | |
555 | return ParseVP8XChunks(dmux); |
556 | } |
557 | |
558 | // ----------------------------------------------------------------------------- |
559 | // Format validation |
560 | |
561 | static int IsValidSimpleFormat(const WebPDemuxer* const dmux) { |
562 | const Frame* const frame = dmux->frames_; |
563 | if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1; |
564 | |
565 | if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0; |
566 | if (dmux->state_ == WEBP_DEMUX_DONE && frame == NULL) return 0; |
567 | |
568 | if (frame->width_ <= 0 || frame->height_ <= 0) return 0; |
569 | return 1; |
570 | } |
571 | |
572 | // If 'exact' is true, check that the image resolution matches the canvas. |
573 | // If 'exact' is false, check that the x/y offsets do not exceed the canvas. |
574 | static int CheckFrameBounds(const Frame* const frame, int exact, |
575 | int canvas_width, int canvas_height) { |
576 | if (exact) { |
577 | if (frame->x_offset_ != 0 || frame->y_offset_ != 0) { |
578 | return 0; |
579 | } |
580 | if (frame->width_ != canvas_width || frame->height_ != canvas_height) { |
581 | return 0; |
582 | } |
583 | } else { |
584 | if (frame->x_offset_ < 0 || frame->y_offset_ < 0) return 0; |
585 | if (frame->width_ + frame->x_offset_ > canvas_width) return 0; |
586 | if (frame->height_ + frame->y_offset_ > canvas_height) return 0; |
587 | } |
588 | return 1; |
589 | } |
590 | |
591 | static int IsValidExtendedFormat(const WebPDemuxer* const dmux) { |
592 | const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
593 | const Frame* f = dmux->frames_; |
594 | |
595 | if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1; |
596 | |
597 | if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0; |
598 | if (dmux->loop_count_ < 0) return 0; |
599 | if (dmux->state_ == WEBP_DEMUX_DONE && dmux->frames_ == NULL) return 0; |
600 | if (dmux->feature_flags_ & ~ALL_VALID_FLAGS) return 0; // invalid bitstream |
601 | |
602 | while (f != NULL) { |
603 | const int cur_frame_set = f->frame_num_; |
604 | int frame_count = 0; |
605 | |
606 | // Check frame properties. |
607 | for (; f != NULL && f->frame_num_ == cur_frame_set; f = f->next_) { |
608 | const ChunkData* const image = f->img_components_; |
609 | const ChunkData* const alpha = f->img_components_ + 1; |
610 | |
611 | if (!is_animation && f->frame_num_ > 1) return 0; |
612 | |
613 | if (f->complete_) { |
614 | if (alpha->size_ == 0 && image->size_ == 0) return 0; |
615 | // Ensure alpha precedes image bitstream. |
616 | if (alpha->size_ > 0 && alpha->offset_ > image->offset_) { |
617 | return 0; |
618 | } |
619 | |
620 | if (f->width_ <= 0 || f->height_ <= 0) return 0; |
621 | } else { |
622 | // There shouldn't be a partial frame in a complete file. |
623 | if (dmux->state_ == WEBP_DEMUX_DONE) return 0; |
624 | |
625 | // Ensure alpha precedes image bitstream. |
626 | if (alpha->size_ > 0 && image->size_ > 0 && |
627 | alpha->offset_ > image->offset_) { |
628 | return 0; |
629 | } |
630 | // There shouldn't be any frames after an incomplete one. |
631 | if (f->next_ != NULL) return 0; |
632 | } |
633 | |
634 | if (f->width_ > 0 && f->height_ > 0 && |
635 | !CheckFrameBounds(f, !is_animation, |
636 | dmux->canvas_width_, dmux->canvas_height_)) { |
637 | return 0; |
638 | } |
639 | |
640 | ++frame_count; |
641 | } |
642 | } |
643 | return 1; |
644 | } |
645 | |
646 | // ----------------------------------------------------------------------------- |
647 | // WebPDemuxer object |
648 | |
649 | static void InitDemux(WebPDemuxer* const dmux, const MemBuffer* const mem) { |
650 | dmux->state_ = WEBP_DEMUX_PARSING_HEADER; |
651 | dmux->loop_count_ = 1; |
652 | dmux->bgcolor_ = 0xFFFFFFFF; // White background by default. |
653 | dmux->canvas_width_ = -1; |
654 | dmux->canvas_height_ = -1; |
655 | dmux->frames_tail_ = &dmux->frames_; |
656 | dmux->chunks_tail_ = &dmux->chunks_; |
657 | dmux->mem_ = *mem; |
658 | } |
659 | |
660 | static ParseStatus CreateRawImageDemuxer(MemBuffer* const mem, |
661 | WebPDemuxer** demuxer) { |
662 | WebPBitstreamFeatures features; |
663 | const VP8StatusCode status = |
664 | WebPGetFeatures(mem->buf_, mem->buf_size_, &features); |
665 | *demuxer = NULL; |
666 | if (status != VP8_STATUS_OK) { |
667 | return (status == VP8_STATUS_NOT_ENOUGH_DATA) ? PARSE_NEED_MORE_DATA |
668 | : PARSE_ERROR; |
669 | } |
670 | |
671 | { |
672 | WebPDemuxer* const dmux = (WebPDemuxer*)WebPSafeCalloc(1ULL, sizeof(*dmux)); |
673 | Frame* const frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(*frame)); |
674 | if (dmux == NULL || frame == NULL) goto Error; |
675 | InitDemux(dmux, mem); |
676 | SetFrameInfo(0, mem->buf_size_, 1 /*frame_num*/, 1 /*complete*/, &features, |
677 | frame); |
678 | if (!AddFrame(dmux, frame)) goto Error; |
679 | dmux->state_ = WEBP_DEMUX_DONE; |
680 | dmux->canvas_width_ = frame->width_; |
681 | dmux->canvas_height_ = frame->height_; |
682 | dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0; |
683 | dmux->num_frames_ = 1; |
684 | assert(IsValidSimpleFormat(dmux)); |
685 | *demuxer = dmux; |
686 | return PARSE_OK; |
687 | |
688 | Error: |
689 | WebPSafeFree(dmux); |
690 | WebPSafeFree(frame); |
691 | return PARSE_ERROR; |
692 | } |
693 | } |
694 | |
695 | WebPDemuxer* WebPDemuxInternal(const WebPData* data, int allow_partial, |
696 | WebPDemuxState* state, int version) { |
697 | const ChunkParser* parser; |
698 | int partial; |
699 | ParseStatus status = PARSE_ERROR; |
700 | MemBuffer mem; |
701 | WebPDemuxer* dmux; |
702 | |
703 | if (state != NULL) *state = WEBP_DEMUX_PARSE_ERROR; |
704 | |
705 | if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DEMUX_ABI_VERSION)) return NULL; |
706 | if (data == NULL || data->bytes == NULL || data->size == 0) return NULL; |
707 | |
708 | if (!InitMemBuffer(&mem, data->bytes, data->size)) return NULL; |
709 | status = ReadHeader(&mem); |
710 | if (status != PARSE_OK) { |
711 | // If parsing of the webp file header fails attempt to handle a raw |
712 | // VP8/VP8L frame. Note 'allow_partial' is ignored in this case. |
713 | if (status == PARSE_ERROR) { |
714 | status = CreateRawImageDemuxer(&mem, &dmux); |
715 | if (status == PARSE_OK) { |
716 | if (state != NULL) *state = WEBP_DEMUX_DONE; |
717 | return dmux; |
718 | } |
719 | } |
720 | if (state != NULL) { |
721 | *state = (status == PARSE_NEED_MORE_DATA) ? WEBP_DEMUX_PARSING_HEADER |
722 | : WEBP_DEMUX_PARSE_ERROR; |
723 | } |
724 | return NULL; |
725 | } |
726 | |
727 | partial = (mem.buf_size_ < mem.riff_end_); |
728 | if (!allow_partial && partial) return NULL; |
729 | |
730 | dmux = (WebPDemuxer*)WebPSafeCalloc(1ULL, sizeof(*dmux)); |
731 | if (dmux == NULL) return NULL; |
732 | InitDemux(dmux, &mem); |
733 | |
734 | status = PARSE_ERROR; |
735 | for (parser = kMasterChunks; parser->parse != NULL; ++parser) { |
736 | if (!memcmp(parser->id, GetBuffer(&dmux->mem_), TAG_SIZE)) { |
737 | status = parser->parse(dmux); |
738 | if (status == PARSE_OK) dmux->state_ = WEBP_DEMUX_DONE; |
739 | if (status == PARSE_NEED_MORE_DATA && !partial) status = PARSE_ERROR; |
740 | if (status != PARSE_ERROR && !parser->valid(dmux)) status = PARSE_ERROR; |
741 | if (status == PARSE_ERROR) dmux->state_ = WEBP_DEMUX_PARSE_ERROR; |
742 | break; |
743 | } |
744 | } |
745 | if (state != NULL) *state = dmux->state_; |
746 | |
747 | if (status == PARSE_ERROR) { |
748 | WebPDemuxDelete(dmux); |
749 | return NULL; |
750 | } |
751 | return dmux; |
752 | } |
753 | |
754 | void WebPDemuxDelete(WebPDemuxer* dmux) { |
755 | Chunk* c; |
756 | Frame* f; |
757 | if (dmux == NULL) return; |
758 | |
759 | for (f = dmux->frames_; f != NULL;) { |
760 | Frame* const cur_frame = f; |
761 | f = f->next_; |
762 | WebPSafeFree(cur_frame); |
763 | } |
764 | for (c = dmux->chunks_; c != NULL;) { |
765 | Chunk* const cur_chunk = c; |
766 | c = c->next_; |
767 | WebPSafeFree(cur_chunk); |
768 | } |
769 | WebPSafeFree(dmux); |
770 | } |
771 | |
772 | // ----------------------------------------------------------------------------- |
773 | |
774 | uint32_t WebPDemuxGetI(const WebPDemuxer* dmux, WebPFormatFeature feature) { |
775 | if (dmux == NULL) return 0; |
776 | |
777 | switch (feature) { |
778 | case WEBP_FF_FORMAT_FLAGS: return dmux->feature_flags_; |
779 | case WEBP_FF_CANVAS_WIDTH: return (uint32_t)dmux->canvas_width_; |
780 | case WEBP_FF_CANVAS_HEIGHT: return (uint32_t)dmux->canvas_height_; |
781 | case WEBP_FF_LOOP_COUNT: return (uint32_t)dmux->loop_count_; |
782 | case WEBP_FF_BACKGROUND_COLOR: return dmux->bgcolor_; |
783 | case WEBP_FF_FRAME_COUNT: return (uint32_t)dmux->num_frames_; |
784 | } |
785 | return 0; |
786 | } |
787 | |
788 | // ----------------------------------------------------------------------------- |
789 | // Frame iteration |
790 | |
791 | static const Frame* GetFrame(const WebPDemuxer* const dmux, int frame_num) { |
792 | const Frame* f; |
793 | for (f = dmux->frames_; f != NULL; f = f->next_) { |
794 | if (frame_num == f->frame_num_) break; |
795 | } |
796 | return f; |
797 | } |
798 | |
799 | static const uint8_t* GetFramePayload(const uint8_t* const mem_buf, |
800 | const Frame* const frame, |
801 | size_t* const data_size) { |
802 | *data_size = 0; |
803 | if (frame != NULL) { |
804 | const ChunkData* const image = frame->img_components_; |
805 | const ChunkData* const alpha = frame->img_components_ + 1; |
806 | size_t start_offset = image->offset_; |
807 | *data_size = image->size_; |
808 | |
809 | // if alpha exists it precedes image, update the size allowing for |
810 | // intervening chunks. |
811 | if (alpha->size_ > 0) { |
812 | const size_t inter_size = (image->offset_ > 0) |
813 | ? image->offset_ - (alpha->offset_ + alpha->size_) |
814 | : 0; |
815 | start_offset = alpha->offset_; |
816 | *data_size += alpha->size_ + inter_size; |
817 | } |
818 | return mem_buf + start_offset; |
819 | } |
820 | return NULL; |
821 | } |
822 | |
823 | // Create a whole 'frame' from VP8 (+ alpha) or lossless. |
824 | static int SynthesizeFrame(const WebPDemuxer* const dmux, |
825 | const Frame* const frame, |
826 | WebPIterator* const iter) { |
827 | const uint8_t* const mem_buf = dmux->mem_.buf_; |
828 | size_t payload_size = 0; |
829 | const uint8_t* const payload = GetFramePayload(mem_buf, frame, &payload_size); |
830 | if (payload == NULL) return 0; |
831 | assert(frame != NULL); |
832 | |
833 | iter->frame_num = frame->frame_num_; |
834 | iter->num_frames = dmux->num_frames_; |
835 | iter->x_offset = frame->x_offset_; |
836 | iter->y_offset = frame->y_offset_; |
837 | iter->width = frame->width_; |
838 | iter->height = frame->height_; |
839 | iter->has_alpha = frame->has_alpha_; |
840 | iter->duration = frame->duration_; |
841 | iter->dispose_method = frame->dispose_method_; |
842 | iter->blend_method = frame->blend_method_; |
843 | iter->complete = frame->complete_; |
844 | iter->fragment.bytes = payload; |
845 | iter->fragment.size = payload_size; |
846 | return 1; |
847 | } |
848 | |
849 | static int SetFrame(int frame_num, WebPIterator* const iter) { |
850 | const Frame* frame; |
851 | const WebPDemuxer* const dmux = (WebPDemuxer*)iter->private_; |
852 | if (dmux == NULL || frame_num < 0) return 0; |
853 | if (frame_num > dmux->num_frames_) return 0; |
854 | if (frame_num == 0) frame_num = dmux->num_frames_; |
855 | |
856 | frame = GetFrame(dmux, frame_num); |
857 | if (frame == NULL) return 0; |
858 | |
859 | return SynthesizeFrame(dmux, frame, iter); |
860 | } |
861 | |
862 | int WebPDemuxGetFrame(const WebPDemuxer* dmux, int frame, WebPIterator* iter) { |
863 | if (iter == NULL) return 0; |
864 | |
865 | memset(iter, 0, sizeof(*iter)); |
866 | iter->private_ = (void*)dmux; |
867 | return SetFrame(frame, iter); |
868 | } |
869 | |
870 | int WebPDemuxNextFrame(WebPIterator* iter) { |
871 | if (iter == NULL) return 0; |
872 | return SetFrame(iter->frame_num + 1, iter); |
873 | } |
874 | |
875 | int WebPDemuxPrevFrame(WebPIterator* iter) { |
876 | if (iter == NULL) return 0; |
877 | if (iter->frame_num <= 1) return 0; |
878 | return SetFrame(iter->frame_num - 1, iter); |
879 | } |
880 | |
881 | void WebPDemuxReleaseIterator(WebPIterator* iter) { |
882 | (void)iter; |
883 | } |
884 | |
885 | // ----------------------------------------------------------------------------- |
886 | // Chunk iteration |
887 | |
888 | static int ChunkCount(const WebPDemuxer* const dmux, const char fourcc[4]) { |
889 | const uint8_t* const mem_buf = dmux->mem_.buf_; |
890 | const Chunk* c; |
891 | int count = 0; |
892 | for (c = dmux->chunks_; c != NULL; c = c->next_) { |
893 | const uint8_t* const = mem_buf + c->data_.offset_; |
894 | if (!memcmp(header, fourcc, TAG_SIZE)) ++count; |
895 | } |
896 | return count; |
897 | } |
898 | |
899 | static const Chunk* GetChunk(const WebPDemuxer* const dmux, |
900 | const char fourcc[4], int chunk_num) { |
901 | const uint8_t* const mem_buf = dmux->mem_.buf_; |
902 | const Chunk* c; |
903 | int count = 0; |
904 | for (c = dmux->chunks_; c != NULL; c = c->next_) { |
905 | const uint8_t* const = mem_buf + c->data_.offset_; |
906 | if (!memcmp(header, fourcc, TAG_SIZE)) ++count; |
907 | if (count == chunk_num) break; |
908 | } |
909 | return c; |
910 | } |
911 | |
912 | static int SetChunk(const char fourcc[4], int chunk_num, |
913 | WebPChunkIterator* const iter) { |
914 | const WebPDemuxer* const dmux = (WebPDemuxer*)iter->private_; |
915 | int count; |
916 | |
917 | if (dmux == NULL || fourcc == NULL || chunk_num < 0) return 0; |
918 | count = ChunkCount(dmux, fourcc); |
919 | if (count == 0) return 0; |
920 | if (chunk_num == 0) chunk_num = count; |
921 | |
922 | if (chunk_num <= count) { |
923 | const uint8_t* const mem_buf = dmux->mem_.buf_; |
924 | const Chunk* const chunk = GetChunk(dmux, fourcc, chunk_num); |
925 | iter->chunk.bytes = mem_buf + chunk->data_.offset_ + CHUNK_HEADER_SIZE; |
926 | iter->chunk.size = chunk->data_.size_ - CHUNK_HEADER_SIZE; |
927 | iter->num_chunks = count; |
928 | iter->chunk_num = chunk_num; |
929 | return 1; |
930 | } |
931 | return 0; |
932 | } |
933 | |
934 | int WebPDemuxGetChunk(const WebPDemuxer* dmux, |
935 | const char fourcc[4], int chunk_num, |
936 | WebPChunkIterator* iter) { |
937 | if (iter == NULL) return 0; |
938 | |
939 | memset(iter, 0, sizeof(*iter)); |
940 | iter->private_ = (void*)dmux; |
941 | return SetChunk(fourcc, chunk_num, iter); |
942 | } |
943 | |
944 | int WebPDemuxNextChunk(WebPChunkIterator* iter) { |
945 | if (iter != NULL) { |
946 | const char* const fourcc = |
947 | (const char*)iter->chunk.bytes - CHUNK_HEADER_SIZE; |
948 | return SetChunk(fourcc, iter->chunk_num + 1, iter); |
949 | } |
950 | return 0; |
951 | } |
952 | |
953 | int WebPDemuxPrevChunk(WebPChunkIterator* iter) { |
954 | if (iter != NULL && iter->chunk_num > 1) { |
955 | const char* const fourcc = |
956 | (const char*)iter->chunk.bytes - CHUNK_HEADER_SIZE; |
957 | return SetChunk(fourcc, iter->chunk_num - 1, iter); |
958 | } |
959 | return 0; |
960 | } |
961 | |
962 | void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter) { |
963 | (void)iter; |
964 | } |
965 | |
966 | |