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// main entry for the decoder
11//
12// Authors: Vikas Arora (vikaas.arora@gmail.com)
13// Jyrki Alakuijala (jyrki@google.com)
14
15#include <stdlib.h>
16
17#include "src/dec/alphai_dec.h"
18#include "src/dec/vp8li_dec.h"
19#include "src/dsp/dsp.h"
20#include "src/dsp/lossless.h"
21#include "src/dsp/lossless_common.h"
22#include "src/dsp/yuv.h"
23#include "src/utils/endian_inl_utils.h"
24#include "src/utils/huffman_utils.h"
25#include "src/utils/utils.h"
26
27#define NUM_ARGB_CACHE_ROWS 16
28
29static const int kCodeLengthLiterals = 16;
30static const int kCodeLengthRepeatCode = 16;
31static const uint8_t kCodeLengthExtraBits[3] = { 2, 3, 7 };
32static const uint8_t kCodeLengthRepeatOffsets[3] = { 3, 3, 11 };
33
34// -----------------------------------------------------------------------------
35// Five Huffman codes are used at each meta code:
36// 1. green + length prefix codes + color cache codes,
37// 2. alpha,
38// 3. red,
39// 4. blue, and,
40// 5. distance prefix codes.
41typedef enum {
42 GREEN = 0,
43 RED = 1,
44 BLUE = 2,
45 ALPHA = 3,
46 DIST = 4
47} HuffIndex;
48
49static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = {
50 NUM_LITERAL_CODES + NUM_LENGTH_CODES,
51 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
52 NUM_DISTANCE_CODES
53};
54
55static const uint8_t kLiteralMap[HUFFMAN_CODES_PER_META_CODE] = {
56 0, 1, 1, 1, 0
57};
58
59#define NUM_CODE_LENGTH_CODES 19
60static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = {
61 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
62};
63
64#define CODE_TO_PLANE_CODES 120
65static const uint8_t kCodeToPlane[CODE_TO_PLANE_CODES] = {
66 0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
67 0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
68 0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
69 0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
70 0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
71 0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
72 0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
73 0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
74 0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
75 0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
76 0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
77 0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70
78};
79
80// Memory needed for lookup tables of one Huffman tree group. Red, blue, alpha
81// and distance alphabets are constant (256 for red, blue and alpha, 40 for
82// distance) and lookup table sizes for them in worst case are 630 and 410
83// respectively. Size of green alphabet depends on color cache size and is equal
84// to 256 (green component values) + 24 (length prefix values)
85// + color_cache_size (between 0 and 2048).
86// All values computed for 8-bit first level lookup with Mark Adler's tool:
87// http://www.hdfgroup.org/ftp/lib-external/zlib/zlib-1.2.5/examples/enough.c
88#define FIXED_TABLE_SIZE (630 * 3 + 410)
89static const uint16_t kTableSize[12] = {
90 FIXED_TABLE_SIZE + 654,
91 FIXED_TABLE_SIZE + 656,
92 FIXED_TABLE_SIZE + 658,
93 FIXED_TABLE_SIZE + 662,
94 FIXED_TABLE_SIZE + 670,
95 FIXED_TABLE_SIZE + 686,
96 FIXED_TABLE_SIZE + 718,
97 FIXED_TABLE_SIZE + 782,
98 FIXED_TABLE_SIZE + 912,
99 FIXED_TABLE_SIZE + 1168,
100 FIXED_TABLE_SIZE + 1680,
101 FIXED_TABLE_SIZE + 2704
102};
103
104static int DecodeImageStream(int xsize, int ysize,
105 int is_level0,
106 VP8LDecoder* const dec,
107 uint32_t** const decoded_data);
108
109//------------------------------------------------------------------------------
110
111int VP8LCheckSignature(const uint8_t* const data, size_t size) {
112 return (size >= VP8L_FRAME_HEADER_SIZE &&
113 data[0] == VP8L_MAGIC_BYTE &&
114 (data[4] >> 5) == 0); // version
115}
116
117static int ReadImageInfo(VP8LBitReader* const br,
118 int* const width, int* const height,
119 int* const has_alpha) {
120 if (VP8LReadBits(br, 8) != VP8L_MAGIC_BYTE) return 0;
121 *width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
122 *height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
123 *has_alpha = VP8LReadBits(br, 1);
124 if (VP8LReadBits(br, VP8L_VERSION_BITS) != 0) return 0;
125 return !br->eos_;
126}
127
128int VP8LGetInfo(const uint8_t* data, size_t data_size,
129 int* const width, int* const height, int* const has_alpha) {
130 if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) {
131 return 0; // not enough data
132 } else if (!VP8LCheckSignature(data, data_size)) {
133 return 0; // bad signature
134 } else {
135 int w, h, a;
136 VP8LBitReader br;
137 VP8LInitBitReader(&br, data, data_size);
138 if (!ReadImageInfo(&br, &w, &h, &a)) {
139 return 0;
140 }
141 if (width != NULL) *width = w;
142 if (height != NULL) *height = h;
143 if (has_alpha != NULL) *has_alpha = a;
144 return 1;
145 }
146}
147
148//------------------------------------------------------------------------------
149
150static WEBP_INLINE int GetCopyDistance(int distance_symbol,
151 VP8LBitReader* const br) {
152 int extra_bits, offset;
153 if (distance_symbol < 4) {
154 return distance_symbol + 1;
155 }
156 extra_bits = (distance_symbol - 2) >> 1;
157 offset = (2 + (distance_symbol & 1)) << extra_bits;
158 return offset + VP8LReadBits(br, extra_bits) + 1;
159}
160
161static WEBP_INLINE int GetCopyLength(int length_symbol,
162 VP8LBitReader* const br) {
163 // Length and distance prefixes are encoded the same way.
164 return GetCopyDistance(length_symbol, br);
165}
166
167static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) {
168 if (plane_code > CODE_TO_PLANE_CODES) {
169 return plane_code - CODE_TO_PLANE_CODES;
170 } else {
171 const int dist_code = kCodeToPlane[plane_code - 1];
172 const int yoffset = dist_code >> 4;
173 const int xoffset = 8 - (dist_code & 0xf);
174 const int dist = yoffset * xsize + xoffset;
175 return (dist >= 1) ? dist : 1; // dist<1 can happen if xsize is very small
176 }
177}
178
179//------------------------------------------------------------------------------
180// Decodes the next Huffman code from bit-stream.
181// FillBitWindow(br) needs to be called at minimum every second call
182// to ReadSymbol, in order to pre-fetch enough bits.
183static WEBP_INLINE int ReadSymbol(const HuffmanCode* table,
184 VP8LBitReader* const br) {
185 int nbits;
186 uint32_t val = VP8LPrefetchBits(br);
187 table += val & HUFFMAN_TABLE_MASK;
188 nbits = table->bits - HUFFMAN_TABLE_BITS;
189 if (nbits > 0) {
190 VP8LSetBitPos(br, br->bit_pos_ + HUFFMAN_TABLE_BITS);
191 val = VP8LPrefetchBits(br);
192 table += table->value;
193 table += val & ((1 << nbits) - 1);
194 }
195 VP8LSetBitPos(br, br->bit_pos_ + table->bits);
196 return table->value;
197}
198
199// Reads packed symbol depending on GREEN channel
200#define BITS_SPECIAL_MARKER 0x100 // something large enough (and a bit-mask)
201#define PACKED_NON_LITERAL_CODE 0 // must be < NUM_LITERAL_CODES
202static WEBP_INLINE int ReadPackedSymbols(const HTreeGroup* group,
203 VP8LBitReader* const br,
204 uint32_t* const dst) {
205 const uint32_t val = VP8LPrefetchBits(br) & (HUFFMAN_PACKED_TABLE_SIZE - 1);
206 const HuffmanCode32 code = group->packed_table[val];
207 assert(group->use_packed_table);
208 if (code.bits < BITS_SPECIAL_MARKER) {
209 VP8LSetBitPos(br, br->bit_pos_ + code.bits);
210 *dst = code.value;
211 return PACKED_NON_LITERAL_CODE;
212 } else {
213 VP8LSetBitPos(br, br->bit_pos_ + code.bits - BITS_SPECIAL_MARKER);
214 assert(code.value >= NUM_LITERAL_CODES);
215 return code.value;
216 }
217}
218
219static int AccumulateHCode(HuffmanCode hcode, int shift,
220 HuffmanCode32* const huff) {
221 huff->bits += hcode.bits;
222 huff->value |= (uint32_t)hcode.value << shift;
223 assert(huff->bits <= HUFFMAN_TABLE_BITS);
224 return hcode.bits;
225}
226
227static void BuildPackedTable(HTreeGroup* const htree_group) {
228 uint32_t code;
229 for (code = 0; code < HUFFMAN_PACKED_TABLE_SIZE; ++code) {
230 uint32_t bits = code;
231 HuffmanCode32* const huff = &htree_group->packed_table[bits];
232 HuffmanCode hcode = htree_group->htrees[GREEN][bits];
233 if (hcode.value >= NUM_LITERAL_CODES) {
234 huff->bits = hcode.bits + BITS_SPECIAL_MARKER;
235 huff->value = hcode.value;
236 } else {
237 huff->bits = 0;
238 huff->value = 0;
239 bits >>= AccumulateHCode(hcode, 8, huff);
240 bits >>= AccumulateHCode(htree_group->htrees[RED][bits], 16, huff);
241 bits >>= AccumulateHCode(htree_group->htrees[BLUE][bits], 0, huff);
242 bits >>= AccumulateHCode(htree_group->htrees[ALPHA][bits], 24, huff);
243 (void)bits;
244 }
245 }
246}
247
248static int ReadHuffmanCodeLengths(
249 VP8LDecoder* const dec, const int* const code_length_code_lengths,
250 int num_symbols, int* const code_lengths) {
251 int ok = 0;
252 VP8LBitReader* const br = &dec->br_;
253 int symbol;
254 int max_symbol;
255 int prev_code_len = DEFAULT_CODE_LENGTH;
256 HuffmanCode table[1 << LENGTHS_TABLE_BITS];
257
258 if (!VP8LBuildHuffmanTable(table, LENGTHS_TABLE_BITS,
259 code_length_code_lengths,
260 NUM_CODE_LENGTH_CODES)) {
261 goto End;
262 }
263
264 if (VP8LReadBits(br, 1)) { // use length
265 const int length_nbits = 2 + 2 * VP8LReadBits(br, 3);
266 max_symbol = 2 + VP8LReadBits(br, length_nbits);
267 if (max_symbol > num_symbols) {
268 goto End;
269 }
270 } else {
271 max_symbol = num_symbols;
272 }
273
274 symbol = 0;
275 while (symbol < num_symbols) {
276 const HuffmanCode* p;
277 int code_len;
278 if (max_symbol-- == 0) break;
279 VP8LFillBitWindow(br);
280 p = &table[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
281 VP8LSetBitPos(br, br->bit_pos_ + p->bits);
282 code_len = p->value;
283 if (code_len < kCodeLengthLiterals) {
284 code_lengths[symbol++] = code_len;
285 if (code_len != 0) prev_code_len = code_len;
286 } else {
287 const int use_prev = (code_len == kCodeLengthRepeatCode);
288 const int slot = code_len - kCodeLengthLiterals;
289 const int extra_bits = kCodeLengthExtraBits[slot];
290 const int repeat_offset = kCodeLengthRepeatOffsets[slot];
291 int repeat = VP8LReadBits(br, extra_bits) + repeat_offset;
292 if (symbol + repeat > num_symbols) {
293 goto End;
294 } else {
295 const int length = use_prev ? prev_code_len : 0;
296 while (repeat-- > 0) code_lengths[symbol++] = length;
297 }
298 }
299 }
300 ok = 1;
301
302 End:
303 if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
304 return ok;
305}
306
307// 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman
308// tree.
309static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
310 int* const code_lengths, HuffmanCode* const table) {
311 int ok = 0;
312 int size = 0;
313 VP8LBitReader* const br = &dec->br_;
314 const int simple_code = VP8LReadBits(br, 1);
315
316 memset(code_lengths, 0, alphabet_size * sizeof(*code_lengths));
317
318 if (simple_code) { // Read symbols, codes & code lengths directly.
319 const int num_symbols = VP8LReadBits(br, 1) + 1;
320 const int first_symbol_len_code = VP8LReadBits(br, 1);
321 // The first code is either 1 bit or 8 bit code.
322 int symbol = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8);
323 code_lengths[symbol] = 1;
324 // The second code (if present), is always 8 bit long.
325 if (num_symbols == 2) {
326 symbol = VP8LReadBits(br, 8);
327 code_lengths[symbol] = 1;
328 }
329 ok = 1;
330 } else { // Decode Huffman-coded code lengths.
331 int i;
332 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
333 const int num_codes = VP8LReadBits(br, 4) + 4;
334 if (num_codes > NUM_CODE_LENGTH_CODES) {
335 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
336 return 0;
337 }
338
339 for (i = 0; i < num_codes; ++i) {
340 code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3);
341 }
342 ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size,
343 code_lengths);
344 }
345
346 ok = ok && !br->eos_;
347 if (ok) {
348 size = VP8LBuildHuffmanTable(table, HUFFMAN_TABLE_BITS,
349 code_lengths, alphabet_size);
350 }
351 if (!ok || size == 0) {
352 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
353 return 0;
354 }
355 return size;
356}
357
358static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
359 int color_cache_bits, int allow_recursion) {
360 int i, j;
361 VP8LBitReader* const br = &dec->br_;
362 VP8LMetadata* const hdr = &dec->hdr_;
363 uint32_t* huffman_image = NULL;
364 HTreeGroup* htree_groups = NULL;
365 HuffmanCode* huffman_tables = NULL;
366 HuffmanCode* huffman_table = NULL;
367 int num_htree_groups = 1;
368 int num_htree_groups_max = 1;
369 int max_alphabet_size = 0;
370 int* code_lengths = NULL;
371 const int table_size = kTableSize[color_cache_bits];
372 int* mapping = NULL;
373 int ok = 0;
374
375 if (allow_recursion && VP8LReadBits(br, 1)) {
376 // use meta Huffman codes.
377 const int huffman_precision = VP8LReadBits(br, 3) + 2;
378 const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
379 const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
380 const int huffman_pixs = huffman_xsize * huffman_ysize;
381 if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec,
382 &huffman_image)) {
383 goto Error;
384 }
385 hdr->huffman_subsample_bits_ = huffman_precision;
386 for (i = 0; i < huffman_pixs; ++i) {
387 // The huffman data is stored in red and green bytes.
388 const int group = (huffman_image[i] >> 8) & 0xffff;
389 huffman_image[i] = group;
390 if (group >= num_htree_groups_max) {
391 num_htree_groups_max = group + 1;
392 }
393 }
394 // Check the validity of num_htree_groups_max. If it seems too big, use a
395 // smaller value for later. This will prevent big memory allocations to end
396 // up with a bad bitstream anyway.
397 // The value of 1000 is totally arbitrary. We know that num_htree_groups_max
398 // is smaller than (1 << 16) and should be smaller than the number of pixels
399 // (though the format allows it to be bigger).
400 if (num_htree_groups_max > 1000 || num_htree_groups_max > xsize * ysize) {
401 // Create a mapping from the used indices to the minimal set of used
402 // values [0, num_htree_groups)
403 mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
404 if (mapping == NULL) {
405 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
406 goto Error;
407 }
408 // -1 means a value is unmapped, and therefore unused in the Huffman
409 // image.
410 memset(mapping, 0xff, num_htree_groups_max * sizeof(*mapping));
411 for (num_htree_groups = 0, i = 0; i < huffman_pixs; ++i) {
412 // Get the current mapping for the group and remap the Huffman image.
413 int* const mapped_group = &mapping[huffman_image[i]];
414 if (*mapped_group == -1) *mapped_group = num_htree_groups++;
415 huffman_image[i] = *mapped_group;
416 }
417 } else {
418 num_htree_groups = num_htree_groups_max;
419 }
420 }
421
422 if (br->eos_) goto Error;
423
424 // Find maximum alphabet size for the htree group.
425 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
426 int alphabet_size = kAlphabetSize[j];
427 if (j == 0 && color_cache_bits > 0) {
428 alphabet_size += 1 << color_cache_bits;
429 }
430 if (max_alphabet_size < alphabet_size) {
431 max_alphabet_size = alphabet_size;
432 }
433 }
434
435 code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
436 sizeof(*code_lengths));
437 huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
438 sizeof(*huffman_tables));
439 htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
440
441 if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
442 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
443 goto Error;
444 }
445
446 huffman_table = huffman_tables;
447 for (i = 0; i < num_htree_groups_max; ++i) {
448 // If the index "i" is unused in the Huffman image, just make sure the
449 // coefficients are valid but do not store them.
450 if (mapping != NULL && mapping[i] == -1) {
451 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
452 int alphabet_size = kAlphabetSize[j];
453 if (j == 0 && color_cache_bits > 0) {
454 alphabet_size += (1 << color_cache_bits);
455 }
456 // Passing in NULL so that nothing gets filled.
457 if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, NULL)) {
458 goto Error;
459 }
460 }
461 } else {
462 HTreeGroup* const htree_group =
463 &htree_groups[(mapping == NULL) ? i : mapping[i]];
464 HuffmanCode** const htrees = htree_group->htrees;
465 int size;
466 int total_size = 0;
467 int is_trivial_literal = 1;
468 int max_bits = 0;
469 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
470 int alphabet_size = kAlphabetSize[j];
471 htrees[j] = huffman_table;
472 if (j == 0 && color_cache_bits > 0) {
473 alphabet_size += (1 << color_cache_bits);
474 }
475 size = ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_table);
476 if (size == 0) {
477 goto Error;
478 }
479 if (is_trivial_literal && kLiteralMap[j] == 1) {
480 is_trivial_literal = (huffman_table->bits == 0);
481 }
482 total_size += huffman_table->bits;
483 huffman_table += size;
484 if (j <= ALPHA) {
485 int local_max_bits = code_lengths[0];
486 int k;
487 for (k = 1; k < alphabet_size; ++k) {
488 if (code_lengths[k] > local_max_bits) {
489 local_max_bits = code_lengths[k];
490 }
491 }
492 max_bits += local_max_bits;
493 }
494 }
495 htree_group->is_trivial_literal = is_trivial_literal;
496 htree_group->is_trivial_code = 0;
497 if (is_trivial_literal) {
498 const int red = htrees[RED][0].value;
499 const int blue = htrees[BLUE][0].value;
500 const int alpha = htrees[ALPHA][0].value;
501 htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue;
502 if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
503 htree_group->is_trivial_code = 1;
504 htree_group->literal_arb |= htrees[GREEN][0].value << 8;
505 }
506 }
507 htree_group->use_packed_table =
508 !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
509 if (htree_group->use_packed_table) BuildPackedTable(htree_group);
510 }
511 }
512 ok = 1;
513
514 // All OK. Finalize pointers.
515 hdr->huffman_image_ = huffman_image;
516 hdr->num_htree_groups_ = num_htree_groups;
517 hdr->htree_groups_ = htree_groups;
518 hdr->huffman_tables_ = huffman_tables;
519
520 Error:
521 WebPSafeFree(code_lengths);
522 WebPSafeFree(mapping);
523 if (!ok) {
524 WebPSafeFree(huffman_image);
525 WebPSafeFree(huffman_tables);
526 VP8LHtreeGroupsFree(htree_groups);
527 }
528 return ok;
529}
530
531//------------------------------------------------------------------------------
532// Scaling.
533
534#if !defined(WEBP_REDUCE_SIZE)
535static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) {
536 const int num_channels = 4;
537 const int in_width = io->mb_w;
538 const int out_width = io->scaled_width;
539 const int in_height = io->mb_h;
540 const int out_height = io->scaled_height;
541 const uint64_t work_size = 2 * num_channels * (uint64_t)out_width;
542 rescaler_t* work; // Rescaler work area.
543 const uint64_t scaled_data_size = (uint64_t)out_width;
544 uint32_t* scaled_data; // Temporary storage for scaled BGRA data.
545 const uint64_t memory_size = sizeof(*dec->rescaler) +
546 work_size * sizeof(*work) +
547 scaled_data_size * sizeof(*scaled_data);
548 uint8_t* memory = (uint8_t*)WebPSafeMalloc(memory_size, sizeof(*memory));
549 if (memory == NULL) {
550 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
551 return 0;
552 }
553 assert(dec->rescaler_memory == NULL);
554 dec->rescaler_memory = memory;
555
556 dec->rescaler = (WebPRescaler*)memory;
557 memory += sizeof(*dec->rescaler);
558 work = (rescaler_t*)memory;
559 memory += work_size * sizeof(*work);
560 scaled_data = (uint32_t*)memory;
561
562 WebPRescalerInit(dec->rescaler, in_width, in_height, (uint8_t*)scaled_data,
563 out_width, out_height, 0, num_channels, work);
564 return 1;
565}
566#endif // WEBP_REDUCE_SIZE
567
568//------------------------------------------------------------------------------
569// Export to ARGB
570
571#if !defined(WEBP_REDUCE_SIZE)
572
573// We have special "export" function since we need to convert from BGRA
574static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace,
575 int rgba_stride, uint8_t* const rgba) {
576 uint32_t* const src = (uint32_t*)rescaler->dst;
577 const int dst_width = rescaler->dst_width;
578 int num_lines_out = 0;
579 while (WebPRescalerHasPendingOutput(rescaler)) {
580 uint8_t* const dst = rgba + num_lines_out * rgba_stride;
581 WebPRescalerExportRow(rescaler);
582 WebPMultARGBRow(src, dst_width, 1);
583 VP8LConvertFromBGRA(src, dst_width, colorspace, dst);
584 ++num_lines_out;
585 }
586 return num_lines_out;
587}
588
589// Emit scaled rows.
590static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec,
591 uint8_t* in, int in_stride, int mb_h,
592 uint8_t* const out, int out_stride) {
593 const WEBP_CSP_MODE colorspace = dec->output_->colorspace;
594 int num_lines_in = 0;
595 int num_lines_out = 0;
596 while (num_lines_in < mb_h) {
597 uint8_t* const row_in = in + num_lines_in * in_stride;
598 uint8_t* const row_out = out + num_lines_out * out_stride;
599 const int lines_left = mb_h - num_lines_in;
600 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
601 int lines_imported;
602 assert(needed_lines > 0 && needed_lines <= lines_left);
603 WebPMultARGBRows(row_in, in_stride,
604 dec->rescaler->src_width, needed_lines, 0);
605 lines_imported =
606 WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride);
607 assert(lines_imported == needed_lines);
608 num_lines_in += lines_imported;
609 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out);
610 }
611 return num_lines_out;
612}
613
614#endif // WEBP_REDUCE_SIZE
615
616// Emit rows without any scaling.
617static int EmitRows(WEBP_CSP_MODE colorspace,
618 const uint8_t* row_in, int in_stride,
619 int mb_w, int mb_h,
620 uint8_t* const out, int out_stride) {
621 int lines = mb_h;
622 uint8_t* row_out = out;
623 while (lines-- > 0) {
624 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out);
625 row_in += in_stride;
626 row_out += out_stride;
627 }
628 return mb_h; // Num rows out == num rows in.
629}
630
631//------------------------------------------------------------------------------
632// Export to YUVA
633
634static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos,
635 const WebPDecBuffer* const output) {
636 const WebPYUVABuffer* const buf = &output->u.YUVA;
637
638 // first, the luma plane
639 WebPConvertARGBToY(src, buf->y + y_pos * buf->y_stride, width);
640
641 // then U/V planes
642 {
643 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride;
644 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride;
645 // even lines: store values
646 // odd lines: average with previous values
647 WebPConvertARGBToUV(src, u, v, width, !(y_pos & 1));
648 }
649 // Lastly, store alpha if needed.
650 if (buf->a != NULL) {
651 uint8_t* const a = buf->a + y_pos * buf->a_stride;
652#if defined(WORDS_BIGENDIAN)
653 WebPExtractAlpha((uint8_t*)src + 0, 0, width, 1, a, 0);
654#else
655 WebPExtractAlpha((uint8_t*)src + 3, 0, width, 1, a, 0);
656#endif
657 }
658}
659
660static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) {
661 WebPRescaler* const rescaler = dec->rescaler;
662 uint32_t* const src = (uint32_t*)rescaler->dst;
663 const int dst_width = rescaler->dst_width;
664 int num_lines_out = 0;
665 while (WebPRescalerHasPendingOutput(rescaler)) {
666 WebPRescalerExportRow(rescaler);
667 WebPMultARGBRow(src, dst_width, 1);
668 ConvertToYUVA(src, dst_width, y_pos, dec->output_);
669 ++y_pos;
670 ++num_lines_out;
671 }
672 return num_lines_out;
673}
674
675static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec,
676 uint8_t* in, int in_stride, int mb_h) {
677 int num_lines_in = 0;
678 int y_pos = dec->last_out_row_;
679 while (num_lines_in < mb_h) {
680 const int lines_left = mb_h - num_lines_in;
681 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
682 int lines_imported;
683 WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0);
684 lines_imported =
685 WebPRescalerImport(dec->rescaler, lines_left, in, in_stride);
686 assert(lines_imported == needed_lines);
687 num_lines_in += lines_imported;
688 in += needed_lines * in_stride;
689 y_pos += ExportYUVA(dec, y_pos);
690 }
691 return y_pos;
692}
693
694static int EmitRowsYUVA(const VP8LDecoder* const dec,
695 const uint8_t* in, int in_stride,
696 int mb_w, int num_rows) {
697 int y_pos = dec->last_out_row_;
698 while (num_rows-- > 0) {
699 ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_);
700 in += in_stride;
701 ++y_pos;
702 }
703 return y_pos;
704}
705
706//------------------------------------------------------------------------------
707// Cropping.
708
709// Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and
710// crop options. Also updates the input data pointer, so that it points to the
711// start of the cropped window. Note that pixels are in ARGB format even if
712// 'in_data' is uint8_t*.
713// Returns true if the crop window is not empty.
714static int SetCropWindow(VP8Io* const io, int y_start, int y_end,
715 uint8_t** const in_data, int pixel_stride) {
716 assert(y_start < y_end);
717 assert(io->crop_left < io->crop_right);
718 if (y_end > io->crop_bottom) {
719 y_end = io->crop_bottom; // make sure we don't overflow on last row.
720 }
721 if (y_start < io->crop_top) {
722 const int delta = io->crop_top - y_start;
723 y_start = io->crop_top;
724 *in_data += delta * pixel_stride;
725 }
726 if (y_start >= y_end) return 0; // Crop window is empty.
727
728 *in_data += io->crop_left * sizeof(uint32_t);
729
730 io->mb_y = y_start - io->crop_top;
731 io->mb_w = io->crop_right - io->crop_left;
732 io->mb_h = y_end - y_start;
733 return 1; // Non-empty crop window.
734}
735
736//------------------------------------------------------------------------------
737
738static WEBP_INLINE int GetMetaIndex(
739 const uint32_t* const image, int xsize, int bits, int x, int y) {
740 if (bits == 0) return 0;
741 return image[xsize * (y >> bits) + (x >> bits)];
742}
743
744static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr,
745 int x, int y) {
746 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_,
747 hdr->huffman_subsample_bits_, x, y);
748 assert(meta_index < hdr->num_htree_groups_);
749 return hdr->htree_groups_ + meta_index;
750}
751
752//------------------------------------------------------------------------------
753// Main loop, with custom row-processing function
754
755typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row);
756
757static void ApplyInverseTransforms(VP8LDecoder* const dec,
758 int start_row, int num_rows,
759 const uint32_t* const rows) {
760 int n = dec->next_transform_;
761 const int cache_pixs = dec->width_ * num_rows;
762 const int end_row = start_row + num_rows;
763 const uint32_t* rows_in = rows;
764 uint32_t* const rows_out = dec->argb_cache_;
765
766 // Inverse transforms.
767 while (n-- > 0) {
768 VP8LTransform* const transform = &dec->transforms_[n];
769 VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out);
770 rows_in = rows_out;
771 }
772 if (rows_in != rows_out) {
773 // No transform called, hence just copy.
774 memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
775 }
776}
777
778// Processes (transforms, scales & color-converts) the rows decoded after the
779// last call.
780static void ProcessRows(VP8LDecoder* const dec, int row) {
781 const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_;
782 const int num_rows = row - dec->last_row_;
783
784 assert(row <= dec->io_->crop_bottom);
785 // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size
786 // of argb_cache_), but we currently don't need more than that.
787 assert(num_rows <= NUM_ARGB_CACHE_ROWS);
788 if (num_rows > 0) { // Emit output.
789 VP8Io* const io = dec->io_;
790 uint8_t* rows_data = (uint8_t*)dec->argb_cache_;
791 const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA
792 ApplyInverseTransforms(dec, dec->last_row_, num_rows, rows);
793 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
794 // Nothing to output (this time).
795 } else {
796 const WebPDecBuffer* const output = dec->output_;
797 if (WebPIsRGBMode(output->colorspace)) { // convert to RGBA
798 const WebPRGBABuffer* const buf = &output->u.RGBA;
799 uint8_t* const rgba = buf->rgba + dec->last_out_row_ * buf->stride;
800 const int num_rows_out =
801#if !defined(WEBP_REDUCE_SIZE)
802 io->use_scaling ?
803 EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h,
804 rgba, buf->stride) :
805#endif // WEBP_REDUCE_SIZE
806 EmitRows(output->colorspace, rows_data, in_stride,
807 io->mb_w, io->mb_h, rgba, buf->stride);
808 // Update 'last_out_row_'.
809 dec->last_out_row_ += num_rows_out;
810 } else { // convert to YUVA
811 dec->last_out_row_ = io->use_scaling ?
812 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) :
813 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h);
814 }
815 assert(dec->last_out_row_ <= output->height);
816 }
817 }
818
819 // Update 'last_row_'.
820 dec->last_row_ = row;
821 assert(dec->last_row_ <= dec->height_);
822}
823
824// Row-processing for the special case when alpha data contains only one
825// transform (color indexing), and trivial non-green literals.
826static int Is8bOptimizable(const VP8LMetadata* const hdr) {
827 int i;
828 if (hdr->color_cache_size_ > 0) return 0;
829 // When the Huffman tree contains only one symbol, we can skip the
830 // call to ReadSymbol() for red/blue/alpha channels.
831 for (i = 0; i < hdr->num_htree_groups_; ++i) {
832 HuffmanCode** const htrees = hdr->htree_groups_[i].htrees;
833 if (htrees[RED][0].bits > 0) return 0;
834 if (htrees[BLUE][0].bits > 0) return 0;
835 if (htrees[ALPHA][0].bits > 0) return 0;
836 }
837 return 1;
838}
839
840static void AlphaApplyFilter(ALPHDecoder* const alph_dec,
841 int first_row, int last_row,
842 uint8_t* out, int stride) {
843 if (alph_dec->filter_ != WEBP_FILTER_NONE) {
844 int y;
845 const uint8_t* prev_line = alph_dec->prev_line_;
846 assert(WebPUnfilters[alph_dec->filter_] != NULL);
847 for (y = first_row; y < last_row; ++y) {
848 WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride);
849 prev_line = out;
850 out += stride;
851 }
852 alph_dec->prev_line_ = prev_line;
853 }
854}
855
856static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) {
857 // For vertical and gradient filtering, we need to decode the part above the
858 // crop_top row, in order to have the correct spatial predictors.
859 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
860 const int top_row =
861 (alph_dec->filter_ == WEBP_FILTER_NONE ||
862 alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top
863 : dec->last_row_;
864 const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_;
865 assert(last_row <= dec->io_->crop_bottom);
866 if (last_row > first_row) {
867 // Special method for paletted alpha data. We only process the cropped area.
868 const int width = dec->io_->width;
869 uint8_t* out = alph_dec->output_ + width * first_row;
870 const uint8_t* const in =
871 (uint8_t*)dec->pixels_ + dec->width_ * first_row;
872 VP8LTransform* const transform = &dec->transforms_[0];
873 assert(dec->next_transform_ == 1);
874 assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
875 VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row,
876 in, out);
877 AlphaApplyFilter(alph_dec, first_row, last_row, out, width);
878 }
879 dec->last_row_ = dec->last_out_row_ = last_row;
880}
881
882//------------------------------------------------------------------------------
883// Helper functions for fast pattern copy (8b and 32b)
884
885// cyclic rotation of pattern word
886static WEBP_INLINE uint32_t Rotate8b(uint32_t V) {
887#if defined(WORDS_BIGENDIAN)
888 return ((V & 0xff000000u) >> 24) | (V << 8);
889#else
890 return ((V & 0xffu) << 24) | (V >> 8);
891#endif
892}
893
894// copy 1, 2 or 4-bytes pattern
895static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst,
896 int length, uint32_t pattern) {
897 int i;
898 // align 'dst' to 4-bytes boundary. Adjust the pattern along the way.
899 while ((uintptr_t)dst & 3) {
900 *dst++ = *src++;
901 pattern = Rotate8b(pattern);
902 --length;
903 }
904 // Copy the pattern 4 bytes at a time.
905 for (i = 0; i < (length >> 2); ++i) {
906 ((uint32_t*)dst)[i] = pattern;
907 }
908 // Finish with left-overs. 'pattern' is still correctly positioned,
909 // so no Rotate8b() call is needed.
910 for (i <<= 2; i < length; ++i) {
911 dst[i] = src[i];
912 }
913}
914
915static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
916 const uint8_t* src = dst - dist;
917 if (length >= 8) {
918 uint32_t pattern = 0;
919 switch (dist) {
920 case 1:
921 pattern = src[0];
922#if defined(__arm__) || defined(_M_ARM) // arm doesn't like multiply that much
923 pattern |= pattern << 8;
924 pattern |= pattern << 16;
925#elif defined(WEBP_USE_MIPS_DSP_R2)
926 __asm__ volatile ("replv.qb %0, %0" : "+r"(pattern));
927#else
928 pattern = 0x01010101u * pattern;
929#endif
930 break;
931 case 2:
932#if !defined(WORDS_BIGENDIAN)
933 memcpy(&pattern, src, sizeof(uint16_t));
934#else
935 pattern = ((uint32_t)src[0] << 8) | src[1];
936#endif
937#if defined(__arm__) || defined(_M_ARM)
938 pattern |= pattern << 16;
939#elif defined(WEBP_USE_MIPS_DSP_R2)
940 __asm__ volatile ("replv.ph %0, %0" : "+r"(pattern));
941#else
942 pattern = 0x00010001u * pattern;
943#endif
944 break;
945 case 4:
946 memcpy(&pattern, src, sizeof(uint32_t));
947 break;
948 default:
949 goto Copy;
950 break;
951 }
952 CopySmallPattern8b(src, dst, length, pattern);
953 return;
954 }
955 Copy:
956 if (dist >= length) { // no overlap -> use memcpy()
957 memcpy(dst, src, length * sizeof(*dst));
958 } else {
959 int i;
960 for (i = 0; i < length; ++i) dst[i] = src[i];
961 }
962}
963
964// copy pattern of 1 or 2 uint32_t's
965static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src,
966 uint32_t* dst,
967 int length, uint64_t pattern) {
968 int i;
969 if ((uintptr_t)dst & 4) { // Align 'dst' to 8-bytes boundary.
970 *dst++ = *src++;
971 pattern = (pattern >> 32) | (pattern << 32);
972 --length;
973 }
974 assert(0 == ((uintptr_t)dst & 7));
975 for (i = 0; i < (length >> 1); ++i) {
976 ((uint64_t*)dst)[i] = pattern; // Copy the pattern 8 bytes at a time.
977 }
978 if (length & 1) { // Finish with left-over.
979 dst[i << 1] = src[i << 1];
980 }
981}
982
983static WEBP_INLINE void CopyBlock32b(uint32_t* const dst,
984 int dist, int length) {
985 const uint32_t* const src = dst - dist;
986 if (dist <= 2 && length >= 4 && ((uintptr_t)dst & 3) == 0) {
987 uint64_t pattern;
988 if (dist == 1) {
989 pattern = (uint64_t)src[0];
990 pattern |= pattern << 32;
991 } else {
992 memcpy(&pattern, src, sizeof(pattern));
993 }
994 CopySmallPattern32b(src, dst, length, pattern);
995 } else if (dist >= length) { // no overlap
996 memcpy(dst, src, length * sizeof(*dst));
997 } else {
998 int i;
999 for (i = 0; i < length; ++i) dst[i] = src[i];
1000 }
1001}
1002
1003//------------------------------------------------------------------------------
1004
1005static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
1006 int width, int height, int last_row) {
1007 int ok = 1;
1008 int row = dec->last_pixel_ / width;
1009 int col = dec->last_pixel_ % width;
1010 VP8LBitReader* const br = &dec->br_;
1011 VP8LMetadata* const hdr = &dec->hdr_;
1012 int pos = dec->last_pixel_; // current position
1013 const int end = width * height; // End of data
1014 const int last = width * last_row; // Last pixel to decode
1015 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1016 const int mask = hdr->huffman_mask_;
1017 const HTreeGroup* htree_group =
1018 (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1019 assert(pos <= end);
1020 assert(last_row <= height);
1021 assert(Is8bOptimizable(hdr));
1022
1023 while (!br->eos_ && pos < last) {
1024 int code;
1025 // Only update when changing tile.
1026 if ((col & mask) == 0) {
1027 htree_group = GetHtreeGroupForPos(hdr, col, row);
1028 }
1029 assert(htree_group != NULL);
1030 VP8LFillBitWindow(br);
1031 code = ReadSymbol(htree_group->htrees[GREEN], br);
1032 if (code < NUM_LITERAL_CODES) { // Literal
1033 data[pos] = code;
1034 ++pos;
1035 ++col;
1036 if (col >= width) {
1037 col = 0;
1038 ++row;
1039 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1040 ExtractPalettedAlphaRows(dec, row);
1041 }
1042 }
1043 } else if (code < len_code_limit) { // Backward reference
1044 int dist_code, dist;
1045 const int length_sym = code - NUM_LITERAL_CODES;
1046 const int length = GetCopyLength(length_sym, br);
1047 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1048 VP8LFillBitWindow(br);
1049 dist_code = GetCopyDistance(dist_symbol, br);
1050 dist = PlaneCodeToDistance(width, dist_code);
1051 if (pos >= dist && end - pos >= length) {
1052 CopyBlock8b(data + pos, dist, length);
1053 } else {
1054 ok = 0;
1055 goto End;
1056 }
1057 pos += length;
1058 col += length;
1059 while (col >= width) {
1060 col -= width;
1061 ++row;
1062 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1063 ExtractPalettedAlphaRows(dec, row);
1064 }
1065 }
1066 if (pos < last && (col & mask)) {
1067 htree_group = GetHtreeGroupForPos(hdr, col, row);
1068 }
1069 } else { // Not reached
1070 ok = 0;
1071 goto End;
1072 }
1073 br->eos_ = VP8LIsEndOfStream(br);
1074 }
1075 // Process the remaining rows corresponding to last row-block.
1076 ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row);
1077
1078 End:
1079 br->eos_ = VP8LIsEndOfStream(br);
1080 if (!ok || (br->eos_ && pos < end)) {
1081 ok = 0;
1082 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED
1083 : VP8_STATUS_BITSTREAM_ERROR;
1084 } else {
1085 dec->last_pixel_ = pos;
1086 }
1087 return ok;
1088}
1089
1090static void SaveState(VP8LDecoder* const dec, int last_pixel) {
1091 assert(dec->incremental_);
1092 dec->saved_br_ = dec->br_;
1093 dec->saved_last_pixel_ = last_pixel;
1094 if (dec->hdr_.color_cache_size_ > 0) {
1095 VP8LColorCacheCopy(&dec->hdr_.color_cache_, &dec->hdr_.saved_color_cache_);
1096 }
1097}
1098
1099static void RestoreState(VP8LDecoder* const dec) {
1100 assert(dec->br_.eos_);
1101 dec->status_ = VP8_STATUS_SUSPENDED;
1102 dec->br_ = dec->saved_br_;
1103 dec->last_pixel_ = dec->saved_last_pixel_;
1104 if (dec->hdr_.color_cache_size_ > 0) {
1105 VP8LColorCacheCopy(&dec->hdr_.saved_color_cache_, &dec->hdr_.color_cache_);
1106 }
1107}
1108
1109#define SYNC_EVERY_N_ROWS 8 // minimum number of rows between check-points
1110static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
1111 int width, int height, int last_row,
1112 ProcessRowsFunc process_func) {
1113 int row = dec->last_pixel_ / width;
1114 int col = dec->last_pixel_ % width;
1115 VP8LBitReader* const br = &dec->br_;
1116 VP8LMetadata* const hdr = &dec->hdr_;
1117 uint32_t* src = data + dec->last_pixel_;
1118 uint32_t* last_cached = src;
1119 uint32_t* const src_end = data + width * height; // End of data
1120 uint32_t* const src_last = data + width * last_row; // Last pixel to decode
1121 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1122 const int color_cache_limit = len_code_limit + hdr->color_cache_size_;
1123 int next_sync_row = dec->incremental_ ? row : 1 << 24;
1124 VP8LColorCache* const color_cache =
1125 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL;
1126 const int mask = hdr->huffman_mask_;
1127 const HTreeGroup* htree_group =
1128 (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1129 assert(dec->last_row_ < last_row);
1130 assert(src_last <= src_end);
1131
1132 while (src < src_last) {
1133 int code;
1134 if (row >= next_sync_row) {
1135 SaveState(dec, (int)(src - data));
1136 next_sync_row = row + SYNC_EVERY_N_ROWS;
1137 }
1138 // Only update when changing tile. Note we could use this test:
1139 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
1140 // but that's actually slower and needs storing the previous col/row.
1141 if ((col & mask) == 0) {
1142 htree_group = GetHtreeGroupForPos(hdr, col, row);
1143 }
1144 assert(htree_group != NULL);
1145 if (htree_group->is_trivial_code) {
1146 *src = htree_group->literal_arb;
1147 goto AdvanceByOne;
1148 }
1149 VP8LFillBitWindow(br);
1150 if (htree_group->use_packed_table) {
1151 code = ReadPackedSymbols(htree_group, br, src);
1152 if (VP8LIsEndOfStream(br)) break;
1153 if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne;
1154 } else {
1155 code = ReadSymbol(htree_group->htrees[GREEN], br);
1156 }
1157 if (VP8LIsEndOfStream(br)) break;
1158 if (code < NUM_LITERAL_CODES) { // Literal
1159 if (htree_group->is_trivial_literal) {
1160 *src = htree_group->literal_arb | (code << 8);
1161 } else {
1162 int red, blue, alpha;
1163 red = ReadSymbol(htree_group->htrees[RED], br);
1164 VP8LFillBitWindow(br);
1165 blue = ReadSymbol(htree_group->htrees[BLUE], br);
1166 alpha = ReadSymbol(htree_group->htrees[ALPHA], br);
1167 if (VP8LIsEndOfStream(br)) break;
1168 *src = ((uint32_t)alpha << 24) | (red << 16) | (code << 8) | blue;
1169 }
1170 AdvanceByOne:
1171 ++src;
1172 ++col;
1173 if (col >= width) {
1174 col = 0;
1175 ++row;
1176 if (process_func != NULL) {
1177 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1178 process_func(dec, row);
1179 }
1180 }
1181 if (color_cache != NULL) {
1182 while (last_cached < src) {
1183 VP8LColorCacheInsert(color_cache, *last_cached++);
1184 }
1185 }
1186 }
1187 } else if (code < len_code_limit) { // Backward reference
1188 int dist_code, dist;
1189 const int length_sym = code - NUM_LITERAL_CODES;
1190 const int length = GetCopyLength(length_sym, br);
1191 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1192 VP8LFillBitWindow(br);
1193 dist_code = GetCopyDistance(dist_symbol, br);
1194 dist = PlaneCodeToDistance(width, dist_code);
1195
1196 if (VP8LIsEndOfStream(br)) break;
1197 if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) {
1198 goto Error;
1199 } else {
1200 CopyBlock32b(src, dist, length);
1201 }
1202 src += length;
1203 col += length;
1204 while (col >= width) {
1205 col -= width;
1206 ++row;
1207 if (process_func != NULL) {
1208 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1209 process_func(dec, row);
1210 }
1211 }
1212 }
1213 // Because of the check done above (before 'src' was incremented by
1214 // 'length'), the following holds true.
1215 assert(src <= src_end);
1216 if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row);
1217 if (color_cache != NULL) {
1218 while (last_cached < src) {
1219 VP8LColorCacheInsert(color_cache, *last_cached++);
1220 }
1221 }
1222 } else if (code < color_cache_limit) { // Color cache
1223 const int key = code - len_code_limit;
1224 assert(color_cache != NULL);
1225 while (last_cached < src) {
1226 VP8LColorCacheInsert(color_cache, *last_cached++);
1227 }
1228 *src = VP8LColorCacheLookup(color_cache, key);
1229 goto AdvanceByOne;
1230 } else { // Not reached
1231 goto Error;
1232 }
1233 }
1234
1235 br->eos_ = VP8LIsEndOfStream(br);
1236 if (dec->incremental_ && br->eos_ && src < src_end) {
1237 RestoreState(dec);
1238 } else if (!br->eos_) {
1239 // Process the remaining rows corresponding to last row-block.
1240 if (process_func != NULL) {
1241 process_func(dec, row > last_row ? last_row : row);
1242 }
1243 dec->status_ = VP8_STATUS_OK;
1244 dec->last_pixel_ = (int)(src - data); // end-of-scan marker
1245 } else {
1246 // if not incremental, and we are past the end of buffer (eos_=1), then this
1247 // is a real bitstream error.
1248 goto Error;
1249 }
1250 return 1;
1251
1252 Error:
1253 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1254 return 0;
1255}
1256
1257// -----------------------------------------------------------------------------
1258// VP8LTransform
1259
1260static void ClearTransform(VP8LTransform* const transform) {
1261 WebPSafeFree(transform->data_);
1262 transform->data_ = NULL;
1263}
1264
1265// For security reason, we need to remap the color map to span
1266// the total possible bundled values, and not just the num_colors.
1267static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
1268 int i;
1269 const int final_num_colors = 1 << (8 >> transform->bits_);
1270 uint32_t* const new_color_map =
1271 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors,
1272 sizeof(*new_color_map));
1273 if (new_color_map == NULL) {
1274 return 0;
1275 } else {
1276 uint8_t* const data = (uint8_t*)transform->data_;
1277 uint8_t* const new_data = (uint8_t*)new_color_map;
1278 new_color_map[0] = transform->data_[0];
1279 for (i = 4; i < 4 * num_colors; ++i) {
1280 // Equivalent to AddPixelEq(), on a byte-basis.
1281 new_data[i] = (data[i] + new_data[i - 4]) & 0xff;
1282 }
1283 for (; i < 4 * final_num_colors; ++i) {
1284 new_data[i] = 0; // black tail.
1285 }
1286 WebPSafeFree(transform->data_);
1287 transform->data_ = new_color_map;
1288 }
1289 return 1;
1290}
1291
1292static int ReadTransform(int* const xsize, int const* ysize,
1293 VP8LDecoder* const dec) {
1294 int ok = 1;
1295 VP8LBitReader* const br = &dec->br_;
1296 VP8LTransform* transform = &dec->transforms_[dec->next_transform_];
1297 const VP8LImageTransformType type =
1298 (VP8LImageTransformType)VP8LReadBits(br, 2);
1299
1300 // Each transform type can only be present once in the stream.
1301 if (dec->transforms_seen_ & (1U << type)) {
1302 return 0; // Already there, let's not accept the second same transform.
1303 }
1304 dec->transforms_seen_ |= (1U << type);
1305
1306 transform->type_ = type;
1307 transform->xsize_ = *xsize;
1308 transform->ysize_ = *ysize;
1309 transform->data_ = NULL;
1310 ++dec->next_transform_;
1311 assert(dec->next_transform_ <= NUM_TRANSFORMS);
1312
1313 switch (type) {
1314 case PREDICTOR_TRANSFORM:
1315 case CROSS_COLOR_TRANSFORM:
1316 transform->bits_ = VP8LReadBits(br, 3) + 2;
1317 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
1318 transform->bits_),
1319 VP8LSubSampleSize(transform->ysize_,
1320 transform->bits_),
1321 0, dec, &transform->data_);
1322 break;
1323 case COLOR_INDEXING_TRANSFORM: {
1324 const int num_colors = VP8LReadBits(br, 8) + 1;
1325 const int bits = (num_colors > 16) ? 0
1326 : (num_colors > 4) ? 1
1327 : (num_colors > 2) ? 2
1328 : 3;
1329 *xsize = VP8LSubSampleSize(transform->xsize_, bits);
1330 transform->bits_ = bits;
1331 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_);
1332 ok = ok && ExpandColorMap(num_colors, transform);
1333 break;
1334 }
1335 case SUBTRACT_GREEN:
1336 break;
1337 default:
1338 assert(0); // can't happen
1339 break;
1340 }
1341
1342 return ok;
1343}
1344
1345// -----------------------------------------------------------------------------
1346// VP8LMetadata
1347
1348static void InitMetadata(VP8LMetadata* const hdr) {
1349 assert(hdr != NULL);
1350 memset(hdr, 0, sizeof(*hdr));
1351}
1352
1353static void ClearMetadata(VP8LMetadata* const hdr) {
1354 assert(hdr != NULL);
1355
1356 WebPSafeFree(hdr->huffman_image_);
1357 WebPSafeFree(hdr->huffman_tables_);
1358 VP8LHtreeGroupsFree(hdr->htree_groups_);
1359 VP8LColorCacheClear(&hdr->color_cache_);
1360 VP8LColorCacheClear(&hdr->saved_color_cache_);
1361 InitMetadata(hdr);
1362}
1363
1364// -----------------------------------------------------------------------------
1365// VP8LDecoder
1366
1367VP8LDecoder* VP8LNew(void) {
1368 VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
1369 if (dec == NULL) return NULL;
1370 dec->status_ = VP8_STATUS_OK;
1371 dec->state_ = READ_DIM;
1372
1373 VP8LDspInit(); // Init critical function pointers.
1374
1375 return dec;
1376}
1377
1378void VP8LClear(VP8LDecoder* const dec) {
1379 int i;
1380 if (dec == NULL) return;
1381 ClearMetadata(&dec->hdr_);
1382
1383 WebPSafeFree(dec->pixels_);
1384 dec->pixels_ = NULL;
1385 for (i = 0; i < dec->next_transform_; ++i) {
1386 ClearTransform(&dec->transforms_[i]);
1387 }
1388 dec->next_transform_ = 0;
1389 dec->transforms_seen_ = 0;
1390
1391 WebPSafeFree(dec->rescaler_memory);
1392 dec->rescaler_memory = NULL;
1393
1394 dec->output_ = NULL; // leave no trace behind
1395}
1396
1397void VP8LDelete(VP8LDecoder* const dec) {
1398 if (dec != NULL) {
1399 VP8LClear(dec);
1400 WebPSafeFree(dec);
1401 }
1402}
1403
1404static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) {
1405 VP8LMetadata* const hdr = &dec->hdr_;
1406 const int num_bits = hdr->huffman_subsample_bits_;
1407 dec->width_ = width;
1408 dec->height_ = height;
1409
1410 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits);
1411 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1;
1412}
1413
1414static int DecodeImageStream(int xsize, int ysize,
1415 int is_level0,
1416 VP8LDecoder* const dec,
1417 uint32_t** const decoded_data) {
1418 int ok = 1;
1419 int transform_xsize = xsize;
1420 int transform_ysize = ysize;
1421 VP8LBitReader* const br = &dec->br_;
1422 VP8LMetadata* const hdr = &dec->hdr_;
1423 uint32_t* data = NULL;
1424 int color_cache_bits = 0;
1425
1426 // Read the transforms (may recurse).
1427 if (is_level0) {
1428 while (ok && VP8LReadBits(br, 1)) {
1429 ok = ReadTransform(&transform_xsize, &transform_ysize, dec);
1430 }
1431 }
1432
1433 // Color cache
1434 if (ok && VP8LReadBits(br, 1)) {
1435 color_cache_bits = VP8LReadBits(br, 4);
1436 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS);
1437 if (!ok) {
1438 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1439 goto End;
1440 }
1441 }
1442
1443 // Read the Huffman codes (may recurse).
1444 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize,
1445 color_cache_bits, is_level0);
1446 if (!ok) {
1447 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1448 goto End;
1449 }
1450
1451 // Finish setting up the color-cache
1452 if (color_cache_bits > 0) {
1453 hdr->color_cache_size_ = 1 << color_cache_bits;
1454 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) {
1455 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1456 ok = 0;
1457 goto End;
1458 }
1459 } else {
1460 hdr->color_cache_size_ = 0;
1461 }
1462 UpdateDecoder(dec, transform_xsize, transform_ysize);
1463
1464 if (is_level0) { // level 0 complete
1465 dec->state_ = READ_HDR;
1466 goto End;
1467 }
1468
1469 {
1470 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize;
1471 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data));
1472 if (data == NULL) {
1473 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1474 ok = 0;
1475 goto End;
1476 }
1477 }
1478
1479 // Use the Huffman trees to decode the LZ77 encoded data.
1480 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize,
1481 transform_ysize, NULL);
1482 ok = ok && !br->eos_;
1483
1484 End:
1485 if (!ok) {
1486 WebPSafeFree(data);
1487 ClearMetadata(hdr);
1488 } else {
1489 if (decoded_data != NULL) {
1490 *decoded_data = data;
1491 } else {
1492 // We allocate image data in this function only for transforms. At level 0
1493 // (that is: not the transforms), we shouldn't have allocated anything.
1494 assert(data == NULL);
1495 assert(is_level0);
1496 }
1497 dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls.
1498 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind.
1499 }
1500 return ok;
1501}
1502
1503//------------------------------------------------------------------------------
1504// Allocate internal buffers dec->pixels_ and dec->argb_cache_.
1505static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) {
1506 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_;
1507 // Scratch buffer corresponding to top-prediction row for transforming the
1508 // first row in the row-blocks. Not needed for paletted alpha.
1509 const uint64_t cache_top_pixels = (uint16_t)final_width;
1510 // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
1511 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS;
1512 const uint64_t total_num_pixels =
1513 num_pixels + cache_top_pixels + cache_pixels;
1514
1515 assert(dec->width_ <= final_width);
1516 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t));
1517 if (dec->pixels_ == NULL) {
1518 dec->argb_cache_ = NULL; // for sanity check
1519 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1520 return 0;
1521 }
1522 dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels;
1523 return 1;
1524}
1525
1526static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
1527 const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_;
1528 dec->argb_cache_ = NULL; // for sanity check
1529 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t));
1530 if (dec->pixels_ == NULL) {
1531 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1532 return 0;
1533 }
1534 return 1;
1535}
1536
1537//------------------------------------------------------------------------------
1538
1539// Special row-processing that only stores the alpha data.
1540static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) {
1541 int cur_row = dec->last_row_;
1542 int num_rows = last_row - cur_row;
1543 const uint32_t* in = dec->pixels_ + dec->width_ * cur_row;
1544
1545 assert(last_row <= dec->io_->crop_bottom);
1546 while (num_rows > 0) {
1547 const int num_rows_to_process =
1548 (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows;
1549 // Extract alpha (which is stored in the green plane).
1550 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
1551 uint8_t* const output = alph_dec->output_;
1552 const int width = dec->io_->width; // the final width (!= dec->width_)
1553 const int cache_pixs = width * num_rows_to_process;
1554 uint8_t* const dst = output + width * cur_row;
1555 const uint32_t* const src = dec->argb_cache_;
1556 ApplyInverseTransforms(dec, cur_row, num_rows_to_process, in);
1557 WebPExtractGreen(src, dst, cache_pixs);
1558 AlphaApplyFilter(alph_dec,
1559 cur_row, cur_row + num_rows_to_process, dst, width);
1560 num_rows -= num_rows_to_process;
1561 in += num_rows_to_process * dec->width_;
1562 cur_row += num_rows_to_process;
1563 }
1564 assert(cur_row == last_row);
1565 dec->last_row_ = dec->last_out_row_ = last_row;
1566}
1567
1568int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
1569 const uint8_t* const data, size_t data_size) {
1570 int ok = 0;
1571 VP8LDecoder* dec = VP8LNew();
1572
1573 if (dec == NULL) return 0;
1574
1575 assert(alph_dec != NULL);
1576
1577 dec->width_ = alph_dec->width_;
1578 dec->height_ = alph_dec->height_;
1579 dec->io_ = &alph_dec->io_;
1580 dec->io_->opaque = alph_dec;
1581 dec->io_->width = alph_dec->width_;
1582 dec->io_->height = alph_dec->height_;
1583
1584 dec->status_ = VP8_STATUS_OK;
1585 VP8LInitBitReader(&dec->br_, data, data_size);
1586
1587 if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) {
1588 goto Err;
1589 }
1590
1591 // Special case: if alpha data uses only the color indexing transform and
1592 // doesn't use color cache (a frequent case), we will use DecodeAlphaData()
1593 // method that only needs allocation of 1 byte per pixel (alpha channel).
1594 if (dec->next_transform_ == 1 &&
1595 dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM &&
1596 Is8bOptimizable(&dec->hdr_)) {
1597 alph_dec->use_8b_decode_ = 1;
1598 ok = AllocateInternalBuffers8b(dec);
1599 } else {
1600 // Allocate internal buffers (note that dec->width_ may have changed here).
1601 alph_dec->use_8b_decode_ = 0;
1602 ok = AllocateInternalBuffers32b(dec, alph_dec->width_);
1603 }
1604
1605 if (!ok) goto Err;
1606
1607 // Only set here, once we are sure it is valid (to avoid thread races).
1608 alph_dec->vp8l_dec_ = dec;
1609 return 1;
1610
1611 Err:
1612 VP8LDelete(dec);
1613 return 0;
1614}
1615
1616int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) {
1617 VP8LDecoder* const dec = alph_dec->vp8l_dec_;
1618 assert(dec != NULL);
1619 assert(last_row <= dec->height_);
1620
1621 if (dec->last_row_ >= last_row) {
1622 return 1; // done
1623 }
1624
1625 if (!alph_dec->use_8b_decode_) WebPInitAlphaProcessing();
1626
1627 // Decode (with special row processing).
1628 return alph_dec->use_8b_decode_ ?
1629 DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
1630 last_row) :
1631 DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1632 last_row, ExtractAlphaRows);
1633}
1634
1635//------------------------------------------------------------------------------
1636
1637int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) {
1638 int width, height, has_alpha;
1639
1640 if (dec == NULL) return 0;
1641 if (io == NULL) {
1642 dec->status_ = VP8_STATUS_INVALID_PARAM;
1643 return 0;
1644 }
1645
1646 dec->io_ = io;
1647 dec->status_ = VP8_STATUS_OK;
1648 VP8LInitBitReader(&dec->br_, io->data, io->data_size);
1649 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) {
1650 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1651 goto Error;
1652 }
1653 dec->state_ = READ_DIM;
1654 io->width = width;
1655 io->height = height;
1656
1657 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error;
1658 return 1;
1659
1660 Error:
1661 VP8LClear(dec);
1662 assert(dec->status_ != VP8_STATUS_OK);
1663 return 0;
1664}
1665
1666int VP8LDecodeImage(VP8LDecoder* const dec) {
1667 VP8Io* io = NULL;
1668 WebPDecParams* params = NULL;
1669
1670 // Sanity checks.
1671 if (dec == NULL) return 0;
1672
1673 assert(dec->hdr_.huffman_tables_ != NULL);
1674 assert(dec->hdr_.htree_groups_ != NULL);
1675 assert(dec->hdr_.num_htree_groups_ > 0);
1676
1677 io = dec->io_;
1678 assert(io != NULL);
1679 params = (WebPDecParams*)io->opaque;
1680 assert(params != NULL);
1681
1682 // Initialization.
1683 if (dec->state_ != READ_DATA) {
1684 dec->output_ = params->output;
1685 assert(dec->output_ != NULL);
1686
1687 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
1688 dec->status_ = VP8_STATUS_INVALID_PARAM;
1689 goto Err;
1690 }
1691
1692 if (!AllocateInternalBuffers32b(dec, io->width)) goto Err;
1693
1694#if !defined(WEBP_REDUCE_SIZE)
1695 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
1696#else
1697 if (io->use_scaling) {
1698 dec->status_ = VP8_STATUS_INVALID_PARAM;
1699 goto Err;
1700 }
1701#endif
1702 if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) {
1703 // need the alpha-multiply functions for premultiplied output or rescaling
1704 WebPInitAlphaProcessing();
1705 }
1706
1707 if (!WebPIsRGBMode(dec->output_->colorspace)) {
1708 WebPInitConvertARGBToYUV();
1709 if (dec->output_->u.YUVA.a != NULL) WebPInitAlphaProcessing();
1710 }
1711 if (dec->incremental_) {
1712 if (dec->hdr_.color_cache_size_ > 0 &&
1713 dec->hdr_.saved_color_cache_.colors_ == NULL) {
1714 if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_,
1715 dec->hdr_.color_cache_.hash_bits_)) {
1716 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1717 goto Err;
1718 }
1719 }
1720 }
1721 dec->state_ = READ_DATA;
1722 }
1723
1724 // Decode.
1725 if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1726 io->crop_bottom, ProcessRows)) {
1727 goto Err;
1728 }
1729
1730 params->last_y = dec->last_out_row_;
1731 return 1;
1732
1733 Err:
1734 VP8LClear(dec);
1735 assert(dec->status_ != VP8_STATUS_OK);
1736 return 0;
1737}
1738
1739//------------------------------------------------------------------------------
1740