1// Copyright 2010 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// Main decoding functions for WEBP images.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include <stdlib.h>
15
16#include "./vp8i_dec.h"
17#include "./vp8li_dec.h"
18#include "./webpi_dec.h"
19#include "../utils/utils.h"
20#include "../webp/mux_types.h" // ALPHA_FLAG
21
22//------------------------------------------------------------------------------
23// RIFF layout is:
24// Offset tag
25// 0...3 "RIFF" 4-byte tag
26// 4...7 size of image data (including metadata) starting at offset 8
27// 8...11 "WEBP" our form-type signature
28// The RIFF container (12 bytes) is followed by appropriate chunks:
29// 12..15 "VP8 ": 4-bytes tags, signaling the use of VP8 video format
30// 16..19 size of the raw VP8 image data, starting at offset 20
31// 20.... the VP8 bytes
32// Or,
33// 12..15 "VP8L": 4-bytes tags, signaling the use of VP8L lossless format
34// 16..19 size of the raw VP8L image data, starting at offset 20
35// 20.... the VP8L bytes
36// Or,
37// 12..15 "VP8X": 4-bytes tags, describing the extended-VP8 chunk.
38// 16..19 size of the VP8X chunk starting at offset 20.
39// 20..23 VP8X flags bit-map corresponding to the chunk-types present.
40// 24..26 Width of the Canvas Image.
41// 27..29 Height of the Canvas Image.
42// There can be extra chunks after the "VP8X" chunk (ICCP, ANMF, VP8, VP8L,
43// XMP, EXIF ...)
44// All sizes are in little-endian order.
45// Note: chunk data size must be padded to multiple of 2 when written.
46
47// Validates the RIFF container (if detected) and skips over it.
48// If a RIFF container is detected, returns:
49// VP8_STATUS_BITSTREAM_ERROR for invalid header,
50// VP8_STATUS_NOT_ENOUGH_DATA for truncated data if have_all_data is true,
51// and VP8_STATUS_OK otherwise.
52// In case there are not enough bytes (partial RIFF container), return 0 for
53// *riff_size. Else return the RIFF size extracted from the header.
54static VP8StatusCode ParseRIFF(const uint8_t** const data,
55 size_t* const data_size, int have_all_data,
56 size_t* const riff_size) {
57 assert(data != NULL);
58 assert(data_size != NULL);
59 assert(riff_size != NULL);
60
61 *riff_size = 0; // Default: no RIFF present.
62 if (*data_size >= RIFF_HEADER_SIZE && !memcmp(*data, "RIFF", TAG_SIZE)) {
63 if (memcmp(*data + 8, "WEBP", TAG_SIZE)) {
64 return VP8_STATUS_BITSTREAM_ERROR; // Wrong image file signature.
65 } else {
66 const uint32_t size = GetLE32(*data + TAG_SIZE);
67 // Check that we have at least one chunk (i.e "WEBP" + "VP8?nnnn").
68 if (size < TAG_SIZE + CHUNK_HEADER_SIZE) {
69 return VP8_STATUS_BITSTREAM_ERROR;
70 }
71 if (size > MAX_CHUNK_PAYLOAD) {
72 return VP8_STATUS_BITSTREAM_ERROR;
73 }
74 if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) {
75 return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream.
76 }
77 // We have a RIFF container. Skip it.
78 *riff_size = size;
79 *data += RIFF_HEADER_SIZE;
80 *data_size -= RIFF_HEADER_SIZE;
81 }
82 }
83 return VP8_STATUS_OK;
84}
85
86// Validates the VP8X header and skips over it.
87// Returns VP8_STATUS_BITSTREAM_ERROR for invalid VP8X header,
88// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
89// VP8_STATUS_OK otherwise.
90// If a VP8X chunk is found, found_vp8x is set to true and *width_ptr,
91// *height_ptr and *flags_ptr are set to the corresponding values extracted
92// from the VP8X chunk.
93static VP8StatusCode ParseVP8X(const uint8_t** const data,
94 size_t* const data_size,
95 int* const found_vp8x,
96 int* const width_ptr, int* const height_ptr,
97 uint32_t* const flags_ptr) {
98 const uint32_t vp8x_size = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE;
99 assert(data != NULL);
100 assert(data_size != NULL);
101 assert(found_vp8x != NULL);
102
103 *found_vp8x = 0;
104
105 if (*data_size < CHUNK_HEADER_SIZE) {
106 return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
107 }
108
109 if (!memcmp(*data, "VP8X", TAG_SIZE)) {
110 int width, height;
111 uint32_t flags;
112 const uint32_t chunk_size = GetLE32(*data + TAG_SIZE);
113 if (chunk_size != VP8X_CHUNK_SIZE) {
114 return VP8_STATUS_BITSTREAM_ERROR; // Wrong chunk size.
115 }
116
117 // Verify if enough data is available to validate the VP8X chunk.
118 if (*data_size < vp8x_size) {
119 return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
120 }
121 flags = GetLE32(*data + 8);
122 width = 1 + GetLE24(*data + 12);
123 height = 1 + GetLE24(*data + 15);
124 if (width * (uint64_t)height >= MAX_IMAGE_AREA) {
125 return VP8_STATUS_BITSTREAM_ERROR; // image is too large
126 }
127
128 if (flags_ptr != NULL) *flags_ptr = flags;
129 if (width_ptr != NULL) *width_ptr = width;
130 if (height_ptr != NULL) *height_ptr = height;
131 // Skip over VP8X header bytes.
132 *data += vp8x_size;
133 *data_size -= vp8x_size;
134 *found_vp8x = 1;
135 }
136 return VP8_STATUS_OK;
137}
138
139// Skips to the next VP8/VP8L chunk header in the data given the size of the
140// RIFF chunk 'riff_size'.
141// Returns VP8_STATUS_BITSTREAM_ERROR if any invalid chunk size is encountered,
142// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
143// VP8_STATUS_OK otherwise.
144// If an alpha chunk is found, *alpha_data and *alpha_size are set
145// appropriately.
146static VP8StatusCode ParseOptionalChunks(const uint8_t** const data,
147 size_t* const data_size,
148 size_t const riff_size,
149 const uint8_t** const alpha_data,
150 size_t* const alpha_size) {
151 const uint8_t* buf;
152 size_t buf_size;
153 uint32_t total_size = TAG_SIZE + // "WEBP".
154 CHUNK_HEADER_SIZE + // "VP8Xnnnn".
155 VP8X_CHUNK_SIZE; // data.
156 assert(data != NULL);
157 assert(data_size != NULL);
158 buf = *data;
159 buf_size = *data_size;
160
161 assert(alpha_data != NULL);
162 assert(alpha_size != NULL);
163 *alpha_data = NULL;
164 *alpha_size = 0;
165
166 while (1) {
167 uint32_t chunk_size;
168 uint32_t disk_chunk_size; // chunk_size with padding
169
170 *data = buf;
171 *data_size = buf_size;
172
173 if (buf_size < CHUNK_HEADER_SIZE) { // Insufficient data.
174 return VP8_STATUS_NOT_ENOUGH_DATA;
175 }
176
177 chunk_size = GetLE32(buf + TAG_SIZE);
178 if (chunk_size > MAX_CHUNK_PAYLOAD) {
179 return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
180 }
181 // For odd-sized chunk-payload, there's one byte padding at the end.
182 disk_chunk_size = (CHUNK_HEADER_SIZE + chunk_size + 1) & ~1;
183 total_size += disk_chunk_size;
184
185 // Check that total bytes skipped so far does not exceed riff_size.
186 if (riff_size > 0 && (total_size > riff_size)) {
187 return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
188 }
189
190 // Start of a (possibly incomplete) VP8/VP8L chunk implies that we have
191 // parsed all the optional chunks.
192 // Note: This check must occur before the check 'buf_size < disk_chunk_size'
193 // below to allow incomplete VP8/VP8L chunks.
194 if (!memcmp(buf, "VP8 ", TAG_SIZE) ||
195 !memcmp(buf, "VP8L", TAG_SIZE)) {
196 return VP8_STATUS_OK;
197 }
198
199 if (buf_size < disk_chunk_size) { // Insufficient data.
200 return VP8_STATUS_NOT_ENOUGH_DATA;
201 }
202
203 if (!memcmp(buf, "ALPH", TAG_SIZE)) { // A valid ALPH header.
204 *alpha_data = buf + CHUNK_HEADER_SIZE;
205 *alpha_size = chunk_size;
206 }
207
208 // We have a full and valid chunk; skip it.
209 buf += disk_chunk_size;
210 buf_size -= disk_chunk_size;
211 }
212}
213
214// Validates the VP8/VP8L Header ("VP8 nnnn" or "VP8L nnnn") and skips over it.
215// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (chunk larger than
216// riff_size) VP8/VP8L header,
217// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
218// VP8_STATUS_OK otherwise.
219// If a VP8/VP8L chunk is found, *chunk_size is set to the total number of bytes
220// extracted from the VP8/VP8L chunk header.
221// The flag '*is_lossless' is set to 1 in case of VP8L chunk / raw VP8L data.
222static VP8StatusCode ParseVP8Header(const uint8_t** const data_ptr,
223 size_t* const data_size, int have_all_data,
224 size_t riff_size, size_t* const chunk_size,
225 int* const is_lossless) {
226 const uint8_t* const data = *data_ptr;
227 const int is_vp8 = !memcmp(data, "VP8 ", TAG_SIZE);
228 const int is_vp8l = !memcmp(data, "VP8L", TAG_SIZE);
229 const uint32_t minimal_size =
230 TAG_SIZE + CHUNK_HEADER_SIZE; // "WEBP" + "VP8 nnnn" OR
231 // "WEBP" + "VP8Lnnnn"
232 assert(data != NULL);
233 assert(data_size != NULL);
234 assert(chunk_size != NULL);
235 assert(is_lossless != NULL);
236
237 if (*data_size < CHUNK_HEADER_SIZE) {
238 return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
239 }
240
241 if (is_vp8 || is_vp8l) {
242 // Bitstream contains VP8/VP8L header.
243 const uint32_t size = GetLE32(data + TAG_SIZE);
244 if ((riff_size >= minimal_size) && (size > riff_size - minimal_size)) {
245 return VP8_STATUS_BITSTREAM_ERROR; // Inconsistent size information.
246 }
247 if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) {
248 return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream.
249 }
250 // Skip over CHUNK_HEADER_SIZE bytes from VP8/VP8L Header.
251 *chunk_size = size;
252 *data_ptr += CHUNK_HEADER_SIZE;
253 *data_size -= CHUNK_HEADER_SIZE;
254 *is_lossless = is_vp8l;
255 } else {
256 // Raw VP8/VP8L bitstream (no header).
257 *is_lossless = VP8LCheckSignature(data, *data_size);
258 *chunk_size = *data_size;
259 }
260
261 return VP8_STATUS_OK;
262}
263
264//------------------------------------------------------------------------------
265
266// Fetch '*width', '*height', '*has_alpha' and fill out 'headers' based on
267// 'data'. All the output parameters may be NULL. If 'headers' is NULL only the
268// minimal amount will be read to fetch the remaining parameters.
269// If 'headers' is non-NULL this function will attempt to locate both alpha
270// data (with or without a VP8X chunk) and the bitstream chunk (VP8/VP8L).
271// Note: The following chunk sequences (before the raw VP8/VP8L data) are
272// considered valid by this function:
273// RIFF + VP8(L)
274// RIFF + VP8X + (optional chunks) + VP8(L)
275// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
276// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
277static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
278 size_t data_size,
279 int* const width,
280 int* const height,
281 int* const has_alpha,
282 int* const has_animation,
283 int* const format,
284 WebPHeaderStructure* const headers) {
285 int canvas_width = 0;
286 int canvas_height = 0;
287 int image_width = 0;
288 int image_height = 0;
289 int found_riff = 0;
290 int found_vp8x = 0;
291 int animation_present = 0;
292 const int have_all_data = (headers != NULL) ? headers->have_all_data : 0;
293
294 VP8StatusCode status;
295 WebPHeaderStructure hdrs;
296
297 if (data == NULL || data_size < RIFF_HEADER_SIZE) {
298 return VP8_STATUS_NOT_ENOUGH_DATA;
299 }
300 memset(&hdrs, 0, sizeof(hdrs));
301 hdrs.data = data;
302 hdrs.data_size = data_size;
303
304 // Skip over RIFF header.
305 status = ParseRIFF(&data, &data_size, have_all_data, &hdrs.riff_size);
306 if (status != VP8_STATUS_OK) {
307 return status; // Wrong RIFF header / insufficient data.
308 }
309 found_riff = (hdrs.riff_size > 0);
310
311 // Skip over VP8X.
312 {
313 uint32_t flags = 0;
314 status = ParseVP8X(&data, &data_size, &found_vp8x,
315 &canvas_width, &canvas_height, &flags);
316 if (status != VP8_STATUS_OK) {
317 return status; // Wrong VP8X / insufficient data.
318 }
319 animation_present = !!(flags & ANIMATION_FLAG);
320 if (!found_riff && found_vp8x) {
321 // Note: This restriction may be removed in the future, if it becomes
322 // necessary to send VP8X chunk to the decoder.
323 return VP8_STATUS_BITSTREAM_ERROR;
324 }
325 if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG);
326 if (has_animation != NULL) *has_animation = animation_present;
327 if (format != NULL) *format = 0; // default = undefined
328
329 image_width = canvas_width;
330 image_height = canvas_height;
331 if (found_vp8x && animation_present && headers == NULL) {
332 status = VP8_STATUS_OK;
333 goto ReturnWidthHeight; // Just return features from VP8X header.
334 }
335 }
336
337 if (data_size < TAG_SIZE) {
338 status = VP8_STATUS_NOT_ENOUGH_DATA;
339 goto ReturnWidthHeight;
340 }
341
342 // Skip over optional chunks if data started with "RIFF + VP8X" or "ALPH".
343 if ((found_riff && found_vp8x) ||
344 (!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
345 status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
346 &hdrs.alpha_data, &hdrs.alpha_data_size);
347 if (status != VP8_STATUS_OK) {
348 goto ReturnWidthHeight; // Invalid chunk size / insufficient data.
349 }
350 }
351
352 // Skip over VP8/VP8L header.
353 status = ParseVP8Header(&data, &data_size, have_all_data, hdrs.riff_size,
354 &hdrs.compressed_size, &hdrs.is_lossless);
355 if (status != VP8_STATUS_OK) {
356 goto ReturnWidthHeight; // Wrong VP8/VP8L chunk-header / insufficient data.
357 }
358 if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
359 return VP8_STATUS_BITSTREAM_ERROR;
360 }
361
362 if (format != NULL && !animation_present) {
363 *format = hdrs.is_lossless ? 2 : 1;
364 }
365
366 if (!hdrs.is_lossless) {
367 if (data_size < VP8_FRAME_HEADER_SIZE) {
368 status = VP8_STATUS_NOT_ENOUGH_DATA;
369 goto ReturnWidthHeight;
370 }
371 // Validates raw VP8 data.
372 if (!VP8GetInfo(data, data_size, (uint32_t)hdrs.compressed_size,
373 &image_width, &image_height)) {
374 return VP8_STATUS_BITSTREAM_ERROR;
375 }
376 } else {
377 if (data_size < VP8L_FRAME_HEADER_SIZE) {
378 status = VP8_STATUS_NOT_ENOUGH_DATA;
379 goto ReturnWidthHeight;
380 }
381 // Validates raw VP8L data.
382 if (!VP8LGetInfo(data, data_size, &image_width, &image_height, has_alpha)) {
383 return VP8_STATUS_BITSTREAM_ERROR;
384 }
385 }
386 // Validates image size coherency.
387 if (found_vp8x) {
388 if (canvas_width != image_width || canvas_height != image_height) {
389 return VP8_STATUS_BITSTREAM_ERROR;
390 }
391 }
392 if (headers != NULL) {
393 *headers = hdrs;
394 headers->offset = data - headers->data;
395 assert((uint64_t)(data - headers->data) < MAX_CHUNK_PAYLOAD);
396 assert(headers->offset == headers->data_size - data_size);
397 }
398 ReturnWidthHeight:
399 if (status == VP8_STATUS_OK ||
400 (status == VP8_STATUS_NOT_ENOUGH_DATA && found_vp8x && headers == NULL)) {
401 if (has_alpha != NULL) {
402 // If the data did not contain a VP8X/VP8L chunk the only definitive way
403 // to set this is by looking for alpha data (from an ALPH chunk).
404 *has_alpha |= (hdrs.alpha_data != NULL);
405 }
406 if (width != NULL) *width = image_width;
407 if (height != NULL) *height = image_height;
408 return VP8_STATUS_OK;
409 } else {
410 return status;
411 }
412}
413
414VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
415 // status is marked volatile as a workaround for a clang-3.8 (aarch64) bug
416 volatile VP8StatusCode status;
417 int has_animation = 0;
418 assert(headers != NULL);
419 // fill out headers, ignore width/height/has_alpha.
420 status = ParseHeadersInternal(headers->data, headers->data_size,
421 NULL, NULL, NULL, &has_animation,
422 NULL, headers);
423 if (status == VP8_STATUS_OK || status == VP8_STATUS_NOT_ENOUGH_DATA) {
424 // TODO(jzern): full support of animation frames will require API additions.
425 if (has_animation) {
426 status = VP8_STATUS_UNSUPPORTED_FEATURE;
427 }
428 }
429 return status;
430}
431
432//------------------------------------------------------------------------------
433// WebPDecParams
434
435void WebPResetDecParams(WebPDecParams* const params) {
436 if (params != NULL) {
437 memset(params, 0, sizeof(*params));
438 }
439}
440
441//------------------------------------------------------------------------------
442// "Into" decoding variants
443
444// Main flow
445static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
446 WebPDecParams* const params) {
447 VP8StatusCode status;
448 VP8Io io;
449 WebPHeaderStructure headers;
450
451 headers.data = data;
452 headers.data_size = data_size;
453 headers.have_all_data = 1;
454 status = WebPParseHeaders(&headers); // Process Pre-VP8 chunks.
455 if (status != VP8_STATUS_OK) {
456 return status;
457 }
458
459 assert(params != NULL);
460 VP8InitIo(&io);
461 io.data = headers.data + headers.offset;
462 io.data_size = headers.data_size - headers.offset;
463 WebPInitCustomIo(params, &io); // Plug the I/O functions.
464
465 if (!headers.is_lossless) {
466 VP8Decoder* const dec = VP8New();
467 if (dec == NULL) {
468 return VP8_STATUS_OUT_OF_MEMORY;
469 }
470 dec->alpha_data_ = headers.alpha_data;
471 dec->alpha_data_size_ = headers.alpha_data_size;
472
473 // Decode bitstream header, update io->width/io->height.
474 if (!VP8GetHeaders(dec, &io)) {
475 status = dec->status_; // An error occurred. Grab error status.
476 } else {
477 // Allocate/check output buffers.
478 status = WebPAllocateDecBuffer(io.width, io.height, params->options,
479 params->output);
480 if (status == VP8_STATUS_OK) { // Decode
481 // This change must be done before calling VP8Decode()
482 dec->mt_method_ = VP8GetThreadMethod(params->options, &headers,
483 io.width, io.height);
484 VP8InitDithering(params->options, dec);
485 if (!VP8Decode(dec, &io)) {
486 status = dec->status_;
487 }
488 }
489 }
490 VP8Delete(dec);
491 } else {
492 VP8LDecoder* const dec = VP8LNew();
493 if (dec == NULL) {
494 return VP8_STATUS_OUT_OF_MEMORY;
495 }
496 if (!VP8LDecodeHeader(dec, &io)) {
497 status = dec->status_; // An error occurred. Grab error status.
498 } else {
499 // Allocate/check output buffers.
500 status = WebPAllocateDecBuffer(io.width, io.height, params->options,
501 params->output);
502 if (status == VP8_STATUS_OK) { // Decode
503 if (!VP8LDecodeImage(dec)) {
504 status = dec->status_;
505 }
506 }
507 }
508 VP8LDelete(dec);
509 }
510
511 if (status != VP8_STATUS_OK) {
512 WebPFreeDecBuffer(params->output);
513 } else {
514 if (params->options != NULL && params->options->flip) {
515 // This restores the original stride values if options->flip was used
516 // during the call to WebPAllocateDecBuffer above.
517 status = WebPFlipBuffer(params->output);
518 }
519 }
520 return status;
521}
522
523// Helpers
524static uint8_t* DecodeIntoRGBABuffer(WEBP_CSP_MODE colorspace,
525 const uint8_t* const data,
526 size_t data_size,
527 uint8_t* const rgba,
528 int stride, size_t size) {
529 WebPDecParams params;
530 WebPDecBuffer buf;
531 if (rgba == NULL) {
532 return NULL;
533 }
534 WebPInitDecBuffer(&buf);
535 WebPResetDecParams(&params);
536 params.output = &buf;
537 buf.colorspace = colorspace;
538 buf.u.RGBA.rgba = rgba;
539 buf.u.RGBA.stride = stride;
540 buf.u.RGBA.size = size;
541 buf.is_external_memory = 1;
542 if (DecodeInto(data, data_size, &params) != VP8_STATUS_OK) {
543 return NULL;
544 }
545 return rgba;
546}
547
548uint8_t* WebPDecodeRGBInto(const uint8_t* data, size_t data_size,
549 uint8_t* output, size_t size, int stride) {
550 return DecodeIntoRGBABuffer(MODE_RGB, data, data_size, output, stride, size);
551}
552
553uint8_t* WebPDecodeRGBAInto(const uint8_t* data, size_t data_size,
554 uint8_t* output, size_t size, int stride) {
555 return DecodeIntoRGBABuffer(MODE_RGBA, data, data_size, output, stride, size);
556}
557
558uint8_t* WebPDecodeARGBInto(const uint8_t* data, size_t data_size,
559 uint8_t* output, size_t size, int stride) {
560 return DecodeIntoRGBABuffer(MODE_ARGB, data, data_size, output, stride, size);
561}
562
563uint8_t* WebPDecodeBGRInto(const uint8_t* data, size_t data_size,
564 uint8_t* output, size_t size, int stride) {
565 return DecodeIntoRGBABuffer(MODE_BGR, data, data_size, output, stride, size);
566}
567
568uint8_t* WebPDecodeBGRAInto(const uint8_t* data, size_t data_size,
569 uint8_t* output, size_t size, int stride) {
570 return DecodeIntoRGBABuffer(MODE_BGRA, data, data_size, output, stride, size);
571}
572
573uint8_t* WebPDecodeYUVInto(const uint8_t* data, size_t data_size,
574 uint8_t* luma, size_t luma_size, int luma_stride,
575 uint8_t* u, size_t u_size, int u_stride,
576 uint8_t* v, size_t v_size, int v_stride) {
577 WebPDecParams params;
578 WebPDecBuffer output;
579 if (luma == NULL) return NULL;
580 WebPInitDecBuffer(&output);
581 WebPResetDecParams(&params);
582 params.output = &output;
583 output.colorspace = MODE_YUV;
584 output.u.YUVA.y = luma;
585 output.u.YUVA.y_stride = luma_stride;
586 output.u.YUVA.y_size = luma_size;
587 output.u.YUVA.u = u;
588 output.u.YUVA.u_stride = u_stride;
589 output.u.YUVA.u_size = u_size;
590 output.u.YUVA.v = v;
591 output.u.YUVA.v_stride = v_stride;
592 output.u.YUVA.v_size = v_size;
593 output.is_external_memory = 1;
594 if (DecodeInto(data, data_size, &params) != VP8_STATUS_OK) {
595 return NULL;
596 }
597 return luma;
598}
599
600//------------------------------------------------------------------------------
601
602static uint8_t* Decode(WEBP_CSP_MODE mode, const uint8_t* const data,
603 size_t data_size, int* const width, int* const height,
604 WebPDecBuffer* const keep_info) {
605 WebPDecParams params;
606 WebPDecBuffer output;
607
608 WebPInitDecBuffer(&output);
609 WebPResetDecParams(&params);
610 params.output = &output;
611 output.colorspace = mode;
612
613 // Retrieve (and report back) the required dimensions from bitstream.
614 if (!WebPGetInfo(data, data_size, &output.width, &output.height)) {
615 return NULL;
616 }
617 if (width != NULL) *width = output.width;
618 if (height != NULL) *height = output.height;
619
620 // Decode
621 if (DecodeInto(data, data_size, &params) != VP8_STATUS_OK) {
622 return NULL;
623 }
624 if (keep_info != NULL) { // keep track of the side-info
625 WebPCopyDecBuffer(&output, keep_info);
626 }
627 // return decoded samples (don't clear 'output'!)
628 return WebPIsRGBMode(mode) ? output.u.RGBA.rgba : output.u.YUVA.y;
629}
630
631uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
632 int* width, int* height) {
633 return Decode(MODE_RGB, data, data_size, width, height, NULL);
634}
635
636uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size,
637 int* width, int* height) {
638 return Decode(MODE_RGBA, data, data_size, width, height, NULL);
639}
640
641uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size,
642 int* width, int* height) {
643 return Decode(MODE_ARGB, data, data_size, width, height, NULL);
644}
645
646uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size,
647 int* width, int* height) {
648 return Decode(MODE_BGR, data, data_size, width, height, NULL);
649}
650
651uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size,
652 int* width, int* height) {
653 return Decode(MODE_BGRA, data, data_size, width, height, NULL);
654}
655
656uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size,
657 int* width, int* height, uint8_t** u, uint8_t** v,
658 int* stride, int* uv_stride) {
659 WebPDecBuffer output; // only to preserve the side-infos
660 uint8_t* const out = Decode(MODE_YUV, data, data_size,
661 width, height, &output);
662
663 if (out != NULL) {
664 const WebPYUVABuffer* const buf = &output.u.YUVA;
665 *u = buf->u;
666 *v = buf->v;
667 *stride = buf->y_stride;
668 *uv_stride = buf->u_stride;
669 assert(buf->u_stride == buf->v_stride);
670 }
671 return out;
672}
673
674static void DefaultFeatures(WebPBitstreamFeatures* const features) {
675 assert(features != NULL);
676 memset(features, 0, sizeof(*features));
677}
678
679static VP8StatusCode GetFeatures(const uint8_t* const data, size_t data_size,
680 WebPBitstreamFeatures* const features) {
681 if (features == NULL || data == NULL) {
682 return VP8_STATUS_INVALID_PARAM;
683 }
684 DefaultFeatures(features);
685
686 // Only parse enough of the data to retrieve the features.
687 return ParseHeadersInternal(data, data_size,
688 &features->width, &features->height,
689 &features->has_alpha, &features->has_animation,
690 &features->format, NULL);
691}
692
693//------------------------------------------------------------------------------
694// WebPGetInfo()
695
696int WebPGetInfo(const uint8_t* data, size_t data_size,
697 int* width, int* height) {
698 WebPBitstreamFeatures features;
699
700 if (GetFeatures(data, data_size, &features) != VP8_STATUS_OK) {
701 return 0;
702 }
703
704 if (width != NULL) {
705 *width = features.width;
706 }
707 if (height != NULL) {
708 *height = features.height;
709 }
710
711 return 1;
712}
713
714//------------------------------------------------------------------------------
715// Advance decoding API
716
717int WebPInitDecoderConfigInternal(WebPDecoderConfig* config,
718 int version) {
719 if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
720 return 0; // version mismatch
721 }
722 if (config == NULL) {
723 return 0;
724 }
725 memset(config, 0, sizeof(*config));
726 DefaultFeatures(&config->input);
727 WebPInitDecBuffer(&config->output);
728 return 1;
729}
730
731VP8StatusCode WebPGetFeaturesInternal(const uint8_t* data, size_t data_size,
732 WebPBitstreamFeatures* features,
733 int version) {
734 if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
735 return VP8_STATUS_INVALID_PARAM; // version mismatch
736 }
737 if (features == NULL) {
738 return VP8_STATUS_INVALID_PARAM;
739 }
740 return GetFeatures(data, data_size, features);
741}
742
743VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
744 WebPDecoderConfig* config) {
745 WebPDecParams params;
746 VP8StatusCode status;
747
748 if (config == NULL) {
749 return VP8_STATUS_INVALID_PARAM;
750 }
751
752 status = GetFeatures(data, data_size, &config->input);
753 if (status != VP8_STATUS_OK) {
754 if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
755 return VP8_STATUS_BITSTREAM_ERROR; // Not-enough-data treated as error.
756 }
757 return status;
758 }
759
760 WebPResetDecParams(&params);
761 params.options = &config->options;
762 params.output = &config->output;
763 if (WebPAvoidSlowMemory(params.output, &config->input)) {
764 // decoding to slow memory: use a temporary in-mem buffer to decode into.
765 WebPDecBuffer in_mem_buffer;
766 WebPInitDecBuffer(&in_mem_buffer);
767 in_mem_buffer.colorspace = config->output.colorspace;
768 in_mem_buffer.width = config->input.width;
769 in_mem_buffer.height = config->input.height;
770 params.output = &in_mem_buffer;
771 status = DecodeInto(data, data_size, &params);
772 if (status == VP8_STATUS_OK) { // do the slow-copy
773 status = WebPCopyDecBufferPixels(&in_mem_buffer, &config->output);
774 }
775 WebPFreeDecBuffer(&in_mem_buffer);
776 } else {
777 status = DecodeInto(data, data_size, &params);
778 }
779
780 return status;
781}
782
783//------------------------------------------------------------------------------
784// Cropping and rescaling.
785
786int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
787 VP8Io* const io, WEBP_CSP_MODE src_colorspace) {
788 const int W = io->width;
789 const int H = io->height;
790 int x = 0, y = 0, w = W, h = H;
791
792 // Cropping
793 io->use_cropping = (options != NULL) && (options->use_cropping > 0);
794 if (io->use_cropping) {
795 w = options->crop_width;
796 h = options->crop_height;
797 x = options->crop_left;
798 y = options->crop_top;
799 if (!WebPIsRGBMode(src_colorspace)) { // only snap for YUV420
800 x &= ~1;
801 y &= ~1;
802 }
803 if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > W || y + h > H) {
804 return 0; // out of frame boundary error
805 }
806 }
807 io->crop_left = x;
808 io->crop_top = y;
809 io->crop_right = x + w;
810 io->crop_bottom = y + h;
811 io->mb_w = w;
812 io->mb_h = h;
813
814 // Scaling
815 io->use_scaling = (options != NULL) && (options->use_scaling > 0);
816 if (io->use_scaling) {
817 int scaled_width = options->scaled_width;
818 int scaled_height = options->scaled_height;
819 if (!WebPRescalerGetScaledDimensions(w, h, &scaled_width, &scaled_height)) {
820 return 0;
821 }
822 io->scaled_width = scaled_width;
823 io->scaled_height = scaled_height;
824 }
825
826 // Filter
827 io->bypass_filtering = (options != NULL) && options->bypass_filtering;
828
829 // Fancy upsampler
830#ifdef FANCY_UPSAMPLING
831 io->fancy_upsampling = (options == NULL) || (!options->no_fancy_upsampling);
832#endif
833
834 if (io->use_scaling) {
835 // disable filter (only for large downscaling ratio).
836 io->bypass_filtering = (io->scaled_width < W * 3 / 4) &&
837 (io->scaled_height < H * 3 / 4);
838 io->fancy_upsampling = 0;
839 }
840 return 1;
841}
842
843//------------------------------------------------------------------------------
844