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// https://github.com/madler/zlib/blob/v1.2.5/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// VP8LFillBitWindow(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 HuffmanTables tables;
257
258 if (!VP8LHuffmanTablesAllocate(1 << LENGTHS_TABLE_BITS, &tables) ||
259 !VP8LBuildHuffmanTable(&tables, LENGTHS_TABLE_BITS,
260 code_length_code_lengths, 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 = &tables.curr_segment->start[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 VP8LHuffmanTablesDeallocate(&tables);
304 if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
305 return ok;
306}
307
308// 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman
309// tree.
310static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
311 int* const code_lengths,
312 HuffmanTables* const table) {
313 int ok = 0;
314 int size = 0;
315 VP8LBitReader* const br = &dec->br_;
316 const int simple_code = VP8LReadBits(br, 1);
317
318 memset(code_lengths, 0, alphabet_size * sizeof(*code_lengths));
319
320 if (simple_code) { // Read symbols, codes & code lengths directly.
321 const int num_symbols = VP8LReadBits(br, 1) + 1;
322 const int first_symbol_len_code = VP8LReadBits(br, 1);
323 // The first code is either 1 bit or 8 bit code.
324 int symbol = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8);
325 code_lengths[symbol] = 1;
326 // The second code (if present), is always 8 bits long.
327 if (num_symbols == 2) {
328 symbol = VP8LReadBits(br, 8);
329 code_lengths[symbol] = 1;
330 }
331 ok = 1;
332 } else { // Decode Huffman-coded code lengths.
333 int i;
334 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
335 const int num_codes = VP8LReadBits(br, 4) + 4;
336 if (num_codes > NUM_CODE_LENGTH_CODES) {
337 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
338 return 0;
339 }
340
341 for (i = 0; i < num_codes; ++i) {
342 code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3);
343 }
344 ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size,
345 code_lengths);
346 }
347
348 ok = ok && !br->eos_;
349 if (ok) {
350 size = VP8LBuildHuffmanTable(table, HUFFMAN_TABLE_BITS,
351 code_lengths, alphabet_size);
352 }
353 if (!ok || size == 0) {
354 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
355 return 0;
356 }
357 return size;
358}
359
360static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
361 int color_cache_bits, int allow_recursion) {
362 int i, j;
363 VP8LBitReader* const br = &dec->br_;
364 VP8LMetadata* const hdr = &dec->hdr_;
365 uint32_t* huffman_image = NULL;
366 HTreeGroup* htree_groups = NULL;
367 HuffmanTables* huffman_tables = &hdr->huffman_tables_;
368 int num_htree_groups = 1;
369 int num_htree_groups_max = 1;
370 int max_alphabet_size = 0;
371 int* code_lengths = NULL;
372 const int table_size = kTableSize[color_cache_bits];
373 int* mapping = NULL;
374 int ok = 0;
375
376 // Check the table has been 0 initialized (through InitMetadata).
377 assert(huffman_tables->root.start == NULL);
378 assert(huffman_tables->curr_segment == NULL);
379
380 if (allow_recursion && VP8LReadBits(br, 1)) {
381 // use meta Huffman codes.
382 const int huffman_precision = VP8LReadBits(br, 3) + 2;
383 const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
384 const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
385 const int huffman_pixs = huffman_xsize * huffman_ysize;
386 if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec,
387 &huffman_image)) {
388 goto Error;
389 }
390 hdr->huffman_subsample_bits_ = huffman_precision;
391 for (i = 0; i < huffman_pixs; ++i) {
392 // The huffman data is stored in red and green bytes.
393 const int group = (huffman_image[i] >> 8) & 0xffff;
394 huffman_image[i] = group;
395 if (group >= num_htree_groups_max) {
396 num_htree_groups_max = group + 1;
397 }
398 }
399 // Check the validity of num_htree_groups_max. If it seems too big, use a
400 // smaller value for later. This will prevent big memory allocations to end
401 // up with a bad bitstream anyway.
402 // The value of 1000 is totally arbitrary. We know that num_htree_groups_max
403 // is smaller than (1 << 16) and should be smaller than the number of pixels
404 // (though the format allows it to be bigger).
405 if (num_htree_groups_max > 1000 || num_htree_groups_max > xsize * ysize) {
406 // Create a mapping from the used indices to the minimal set of used
407 // values [0, num_htree_groups)
408 mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
409 if (mapping == NULL) {
410 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
411 goto Error;
412 }
413 // -1 means a value is unmapped, and therefore unused in the Huffman
414 // image.
415 memset(mapping, 0xff, num_htree_groups_max * sizeof(*mapping));
416 for (num_htree_groups = 0, i = 0; i < huffman_pixs; ++i) {
417 // Get the current mapping for the group and remap the Huffman image.
418 int* const mapped_group = &mapping[huffman_image[i]];
419 if (*mapped_group == -1) *mapped_group = num_htree_groups++;
420 huffman_image[i] = *mapped_group;
421 }
422 } else {
423 num_htree_groups = num_htree_groups_max;
424 }
425 }
426
427 if (br->eos_) goto Error;
428
429 // Find maximum alphabet size for the htree group.
430 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
431 int alphabet_size = kAlphabetSize[j];
432 if (j == 0 && color_cache_bits > 0) {
433 alphabet_size += 1 << color_cache_bits;
434 }
435 if (max_alphabet_size < alphabet_size) {
436 max_alphabet_size = alphabet_size;
437 }
438 }
439
440 code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
441 sizeof(*code_lengths));
442 htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
443
444 if (htree_groups == NULL || code_lengths == NULL ||
445 !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
446 huffman_tables)) {
447 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
448 goto Error;
449 }
450
451 for (i = 0; i < num_htree_groups_max; ++i) {
452 // If the index "i" is unused in the Huffman image, just make sure the
453 // coefficients are valid but do not store them.
454 if (mapping != NULL && mapping[i] == -1) {
455 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
456 int alphabet_size = kAlphabetSize[j];
457 if (j == 0 && color_cache_bits > 0) {
458 alphabet_size += (1 << color_cache_bits);
459 }
460 // Passing in NULL so that nothing gets filled.
461 if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, NULL)) {
462 goto Error;
463 }
464 }
465 } else {
466 HTreeGroup* const htree_group =
467 &htree_groups[(mapping == NULL) ? i : mapping[i]];
468 HuffmanCode** const htrees = htree_group->htrees;
469 int size;
470 int total_size = 0;
471 int is_trivial_literal = 1;
472 int max_bits = 0;
473 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
474 int alphabet_size = kAlphabetSize[j];
475 if (j == 0 && color_cache_bits > 0) {
476 alphabet_size += (1 << color_cache_bits);
477 }
478 size =
479 ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables);
480 htrees[j] = huffman_tables->curr_segment->curr_table;
481 if (size == 0) {
482 goto Error;
483 }
484 if (is_trivial_literal && kLiteralMap[j] == 1) {
485 is_trivial_literal = (htrees[j]->bits == 0);
486 }
487 total_size += htrees[j]->bits;
488 huffman_tables->curr_segment->curr_table += size;
489 if (j <= ALPHA) {
490 int local_max_bits = code_lengths[0];
491 int k;
492 for (k = 1; k < alphabet_size; ++k) {
493 if (code_lengths[k] > local_max_bits) {
494 local_max_bits = code_lengths[k];
495 }
496 }
497 max_bits += local_max_bits;
498 }
499 }
500 htree_group->is_trivial_literal = is_trivial_literal;
501 htree_group->is_trivial_code = 0;
502 if (is_trivial_literal) {
503 const int red = htrees[RED][0].value;
504 const int blue = htrees[BLUE][0].value;
505 const int alpha = htrees[ALPHA][0].value;
506 htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue;
507 if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
508 htree_group->is_trivial_code = 1;
509 htree_group->literal_arb |= htrees[GREEN][0].value << 8;
510 }
511 }
512 htree_group->use_packed_table =
513 !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
514 if (htree_group->use_packed_table) BuildPackedTable(htree_group);
515 }
516 }
517 ok = 1;
518
519 // All OK. Finalize pointers.
520 hdr->huffman_image_ = huffman_image;
521 hdr->num_htree_groups_ = num_htree_groups;
522 hdr->htree_groups_ = htree_groups;
523
524 Error:
525 WebPSafeFree(code_lengths);
526 WebPSafeFree(mapping);
527 if (!ok) {
528 WebPSafeFree(huffman_image);
529 VP8LHuffmanTablesDeallocate(huffman_tables);
530 VP8LHtreeGroupsFree(htree_groups);
531 }
532 return ok;
533}
534
535//------------------------------------------------------------------------------
536// Scaling.
537
538#if !defined(WEBP_REDUCE_SIZE)
539static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) {
540 const int num_channels = 4;
541 const int in_width = io->mb_w;
542 const int out_width = io->scaled_width;
543 const int in_height = io->mb_h;
544 const int out_height = io->scaled_height;
545 const uint64_t work_size = 2 * num_channels * (uint64_t)out_width;
546 rescaler_t* work; // Rescaler work area.
547 const uint64_t scaled_data_size = (uint64_t)out_width;
548 uint32_t* scaled_data; // Temporary storage for scaled BGRA data.
549 const uint64_t memory_size = sizeof(*dec->rescaler) +
550 work_size * sizeof(*work) +
551 scaled_data_size * sizeof(*scaled_data);
552 uint8_t* memory = (uint8_t*)WebPSafeMalloc(memory_size, sizeof(*memory));
553 if (memory == NULL) {
554 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
555 return 0;
556 }
557 assert(dec->rescaler_memory == NULL);
558 dec->rescaler_memory = memory;
559
560 dec->rescaler = (WebPRescaler*)memory;
561 memory += sizeof(*dec->rescaler);
562 work = (rescaler_t*)memory;
563 memory += work_size * sizeof(*work);
564 scaled_data = (uint32_t*)memory;
565
566 if (!WebPRescalerInit(dec->rescaler, in_width, in_height,
567 (uint8_t*)scaled_data, out_width, out_height,
568 0, num_channels, work)) {
569 return 0;
570 }
571 return 1;
572}
573#endif // WEBP_REDUCE_SIZE
574
575//------------------------------------------------------------------------------
576// Export to ARGB
577
578#if !defined(WEBP_REDUCE_SIZE)
579
580// We have special "export" function since we need to convert from BGRA
581static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace,
582 int rgba_stride, uint8_t* const rgba) {
583 uint32_t* const src = (uint32_t*)rescaler->dst;
584 uint8_t* dst = rgba;
585 const int dst_width = rescaler->dst_width;
586 int num_lines_out = 0;
587 while (WebPRescalerHasPendingOutput(rescaler)) {
588 WebPRescalerExportRow(rescaler);
589 WebPMultARGBRow(src, dst_width, 1);
590 VP8LConvertFromBGRA(src, dst_width, colorspace, dst);
591 dst += rgba_stride;
592 ++num_lines_out;
593 }
594 return num_lines_out;
595}
596
597// Emit scaled rows.
598static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec,
599 uint8_t* in, int in_stride, int mb_h,
600 uint8_t* const out, int out_stride) {
601 const WEBP_CSP_MODE colorspace = dec->output_->colorspace;
602 int num_lines_in = 0;
603 int num_lines_out = 0;
604 while (num_lines_in < mb_h) {
605 uint8_t* const row_in = in + (uint64_t)num_lines_in * in_stride;
606 uint8_t* const row_out = out + (uint64_t)num_lines_out * out_stride;
607 const int lines_left = mb_h - num_lines_in;
608 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
609 int lines_imported;
610 assert(needed_lines > 0 && needed_lines <= lines_left);
611 WebPMultARGBRows(row_in, in_stride,
612 dec->rescaler->src_width, needed_lines, 0);
613 lines_imported =
614 WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride);
615 assert(lines_imported == needed_lines);
616 num_lines_in += lines_imported;
617 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out);
618 }
619 return num_lines_out;
620}
621
622#endif // WEBP_REDUCE_SIZE
623
624// Emit rows without any scaling.
625static int EmitRows(WEBP_CSP_MODE colorspace,
626 const uint8_t* row_in, int in_stride,
627 int mb_w, int mb_h,
628 uint8_t* const out, int out_stride) {
629 int lines = mb_h;
630 uint8_t* row_out = out;
631 while (lines-- > 0) {
632 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out);
633 row_in += in_stride;
634 row_out += out_stride;
635 }
636 return mb_h; // Num rows out == num rows in.
637}
638
639//------------------------------------------------------------------------------
640// Export to YUVA
641
642static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos,
643 const WebPDecBuffer* const output) {
644 const WebPYUVABuffer* const buf = &output->u.YUVA;
645
646 // first, the luma plane
647 WebPConvertARGBToY(src, buf->y + y_pos * buf->y_stride, width);
648
649 // then U/V planes
650 {
651 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride;
652 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride;
653 // even lines: store values
654 // odd lines: average with previous values
655 WebPConvertARGBToUV(src, u, v, width, !(y_pos & 1));
656 }
657 // Lastly, store alpha if needed.
658 if (buf->a != NULL) {
659 uint8_t* const a = buf->a + y_pos * buf->a_stride;
660#if defined(WORDS_BIGENDIAN)
661 WebPExtractAlpha((uint8_t*)src + 0, 0, width, 1, a, 0);
662#else
663 WebPExtractAlpha((uint8_t*)src + 3, 0, width, 1, a, 0);
664#endif
665 }
666}
667
668static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) {
669 WebPRescaler* const rescaler = dec->rescaler;
670 uint32_t* const src = (uint32_t*)rescaler->dst;
671 const int dst_width = rescaler->dst_width;
672 int num_lines_out = 0;
673 while (WebPRescalerHasPendingOutput(rescaler)) {
674 WebPRescalerExportRow(rescaler);
675 WebPMultARGBRow(src, dst_width, 1);
676 ConvertToYUVA(src, dst_width, y_pos, dec->output_);
677 ++y_pos;
678 ++num_lines_out;
679 }
680 return num_lines_out;
681}
682
683static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec,
684 uint8_t* in, int in_stride, int mb_h) {
685 int num_lines_in = 0;
686 int y_pos = dec->last_out_row_;
687 while (num_lines_in < mb_h) {
688 const int lines_left = mb_h - num_lines_in;
689 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
690 int lines_imported;
691 WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0);
692 lines_imported =
693 WebPRescalerImport(dec->rescaler, lines_left, in, in_stride);
694 assert(lines_imported == needed_lines);
695 num_lines_in += lines_imported;
696 in += needed_lines * in_stride;
697 y_pos += ExportYUVA(dec, y_pos);
698 }
699 return y_pos;
700}
701
702static int EmitRowsYUVA(const VP8LDecoder* const dec,
703 const uint8_t* in, int in_stride,
704 int mb_w, int num_rows) {
705 int y_pos = dec->last_out_row_;
706 while (num_rows-- > 0) {
707 ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_);
708 in += in_stride;
709 ++y_pos;
710 }
711 return y_pos;
712}
713
714//------------------------------------------------------------------------------
715// Cropping.
716
717// Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and
718// crop options. Also updates the input data pointer, so that it points to the
719// start of the cropped window. Note that pixels are in ARGB format even if
720// 'in_data' is uint8_t*.
721// Returns true if the crop window is not empty.
722static int SetCropWindow(VP8Io* const io, int y_start, int y_end,
723 uint8_t** const in_data, int pixel_stride) {
724 assert(y_start < y_end);
725 assert(io->crop_left < io->crop_right);
726 if (y_end > io->crop_bottom) {
727 y_end = io->crop_bottom; // make sure we don't overflow on last row.
728 }
729 if (y_start < io->crop_top) {
730 const int delta = io->crop_top - y_start;
731 y_start = io->crop_top;
732 *in_data += delta * pixel_stride;
733 }
734 if (y_start >= y_end) return 0; // Crop window is empty.
735
736 *in_data += io->crop_left * sizeof(uint32_t);
737
738 io->mb_y = y_start - io->crop_top;
739 io->mb_w = io->crop_right - io->crop_left;
740 io->mb_h = y_end - y_start;
741 return 1; // Non-empty crop window.
742}
743
744//------------------------------------------------------------------------------
745
746static WEBP_INLINE int GetMetaIndex(
747 const uint32_t* const image, int xsize, int bits, int x, int y) {
748 if (bits == 0) return 0;
749 return image[xsize * (y >> bits) + (x >> bits)];
750}
751
752static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr,
753 int x, int y) {
754 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_,
755 hdr->huffman_subsample_bits_, x, y);
756 assert(meta_index < hdr->num_htree_groups_);
757 return hdr->htree_groups_ + meta_index;
758}
759
760//------------------------------------------------------------------------------
761// Main loop, with custom row-processing function
762
763typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row);
764
765static void ApplyInverseTransforms(VP8LDecoder* const dec,
766 int start_row, int num_rows,
767 const uint32_t* const rows) {
768 int n = dec->next_transform_;
769 const int cache_pixs = dec->width_ * num_rows;
770 const int end_row = start_row + num_rows;
771 const uint32_t* rows_in = rows;
772 uint32_t* const rows_out = dec->argb_cache_;
773
774 // Inverse transforms.
775 while (n-- > 0) {
776 VP8LTransform* const transform = &dec->transforms_[n];
777 VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out);
778 rows_in = rows_out;
779 }
780 if (rows_in != rows_out) {
781 // No transform called, hence just copy.
782 memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
783 }
784}
785
786// Processes (transforms, scales & color-converts) the rows decoded after the
787// last call.
788static void ProcessRows(VP8LDecoder* const dec, int row) {
789 const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_;
790 const int num_rows = row - dec->last_row_;
791
792 assert(row <= dec->io_->crop_bottom);
793 // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size
794 // of argb_cache_), but we currently don't need more than that.
795 assert(num_rows <= NUM_ARGB_CACHE_ROWS);
796 if (num_rows > 0) { // Emit output.
797 VP8Io* const io = dec->io_;
798 uint8_t* rows_data = (uint8_t*)dec->argb_cache_;
799 const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA
800 ApplyInverseTransforms(dec, dec->last_row_, num_rows, rows);
801 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
802 // Nothing to output (this time).
803 } else {
804 const WebPDecBuffer* const output = dec->output_;
805 if (WebPIsRGBMode(output->colorspace)) { // convert to RGBA
806 const WebPRGBABuffer* const buf = &output->u.RGBA;
807 uint8_t* const rgba =
808 buf->rgba + (int64_t)dec->last_out_row_ * buf->stride;
809 const int num_rows_out =
810#if !defined(WEBP_REDUCE_SIZE)
811 io->use_scaling ?
812 EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h,
813 rgba, buf->stride) :
814#endif // WEBP_REDUCE_SIZE
815 EmitRows(output->colorspace, rows_data, in_stride,
816 io->mb_w, io->mb_h, rgba, buf->stride);
817 // Update 'last_out_row_'.
818 dec->last_out_row_ += num_rows_out;
819 } else { // convert to YUVA
820 dec->last_out_row_ = io->use_scaling ?
821 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) :
822 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h);
823 }
824 assert(dec->last_out_row_ <= output->height);
825 }
826 }
827
828 // Update 'last_row_'.
829 dec->last_row_ = row;
830 assert(dec->last_row_ <= dec->height_);
831}
832
833// Row-processing for the special case when alpha data contains only one
834// transform (color indexing), and trivial non-green literals.
835static int Is8bOptimizable(const VP8LMetadata* const hdr) {
836 int i;
837 if (hdr->color_cache_size_ > 0) return 0;
838 // When the Huffman tree contains only one symbol, we can skip the
839 // call to ReadSymbol() for red/blue/alpha channels.
840 for (i = 0; i < hdr->num_htree_groups_; ++i) {
841 HuffmanCode** const htrees = hdr->htree_groups_[i].htrees;
842 if (htrees[RED][0].bits > 0) return 0;
843 if (htrees[BLUE][0].bits > 0) return 0;
844 if (htrees[ALPHA][0].bits > 0) return 0;
845 }
846 return 1;
847}
848
849static void AlphaApplyFilter(ALPHDecoder* const alph_dec,
850 int first_row, int last_row,
851 uint8_t* out, int stride) {
852 if (alph_dec->filter_ != WEBP_FILTER_NONE) {
853 int y;
854 const uint8_t* prev_line = alph_dec->prev_line_;
855 assert(WebPUnfilters[alph_dec->filter_] != NULL);
856 for (y = first_row; y < last_row; ++y) {
857 WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride);
858 prev_line = out;
859 out += stride;
860 }
861 alph_dec->prev_line_ = prev_line;
862 }
863}
864
865static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) {
866 // For vertical and gradient filtering, we need to decode the part above the
867 // crop_top row, in order to have the correct spatial predictors.
868 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
869 const int top_row =
870 (alph_dec->filter_ == WEBP_FILTER_NONE ||
871 alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top
872 : dec->last_row_;
873 const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_;
874 assert(last_row <= dec->io_->crop_bottom);
875 if (last_row > first_row) {
876 // Special method for paletted alpha data. We only process the cropped area.
877 const int width = dec->io_->width;
878 uint8_t* out = alph_dec->output_ + width * first_row;
879 const uint8_t* const in =
880 (uint8_t*)dec->pixels_ + dec->width_ * first_row;
881 VP8LTransform* const transform = &dec->transforms_[0];
882 assert(dec->next_transform_ == 1);
883 assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
884 VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row,
885 in, out);
886 AlphaApplyFilter(alph_dec, first_row, last_row, out, width);
887 }
888 dec->last_row_ = dec->last_out_row_ = last_row;
889}
890
891//------------------------------------------------------------------------------
892// Helper functions for fast pattern copy (8b and 32b)
893
894// cyclic rotation of pattern word
895static WEBP_INLINE uint32_t Rotate8b(uint32_t V) {
896#if defined(WORDS_BIGENDIAN)
897 return ((V & 0xff000000u) >> 24) | (V << 8);
898#else
899 return ((V & 0xffu) << 24) | (V >> 8);
900#endif
901}
902
903// copy 1, 2 or 4-bytes pattern
904static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst,
905 int length, uint32_t pattern) {
906 int i;
907 // align 'dst' to 4-bytes boundary. Adjust the pattern along the way.
908 while ((uintptr_t)dst & 3) {
909 *dst++ = *src++;
910 pattern = Rotate8b(pattern);
911 --length;
912 }
913 // Copy the pattern 4 bytes at a time.
914 for (i = 0; i < (length >> 2); ++i) {
915 ((uint32_t*)dst)[i] = pattern;
916 }
917 // Finish with left-overs. 'pattern' is still correctly positioned,
918 // so no Rotate8b() call is needed.
919 for (i <<= 2; i < length; ++i) {
920 dst[i] = src[i];
921 }
922}
923
924static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
925 const uint8_t* src = dst - dist;
926 if (length >= 8) {
927 uint32_t pattern = 0;
928 switch (dist) {
929 case 1:
930 pattern = src[0];
931#if defined(__arm__) || defined(_M_ARM) // arm doesn't like multiply that much
932 pattern |= pattern << 8;
933 pattern |= pattern << 16;
934#elif defined(WEBP_USE_MIPS_DSP_R2)
935 __asm__ volatile ("replv.qb %0, %0" : "+r"(pattern));
936#else
937 pattern = 0x01010101u * pattern;
938#endif
939 break;
940 case 2:
941#if !defined(WORDS_BIGENDIAN)
942 memcpy(&pattern, src, sizeof(uint16_t));
943#else
944 pattern = ((uint32_t)src[0] << 8) | src[1];
945#endif
946#if defined(__arm__) || defined(_M_ARM)
947 pattern |= pattern << 16;
948#elif defined(WEBP_USE_MIPS_DSP_R2)
949 __asm__ volatile ("replv.ph %0, %0" : "+r"(pattern));
950#else
951 pattern = 0x00010001u * pattern;
952#endif
953 break;
954 case 4:
955 memcpy(&pattern, src, sizeof(uint32_t));
956 break;
957 default:
958 goto Copy;
959 }
960 CopySmallPattern8b(src, dst, length, pattern);
961 return;
962 }
963 Copy:
964 if (dist >= length) { // no overlap -> use memcpy()
965 memcpy(dst, src, length * sizeof(*dst));
966 } else {
967 int i;
968 for (i = 0; i < length; ++i) dst[i] = src[i];
969 }
970}
971
972// copy pattern of 1 or 2 uint32_t's
973static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src,
974 uint32_t* dst,
975 int length, uint64_t pattern) {
976 int i;
977 if ((uintptr_t)dst & 4) { // Align 'dst' to 8-bytes boundary.
978 *dst++ = *src++;
979 pattern = (pattern >> 32) | (pattern << 32);
980 --length;
981 }
982 assert(0 == ((uintptr_t)dst & 7));
983 for (i = 0; i < (length >> 1); ++i) {
984 ((uint64_t*)dst)[i] = pattern; // Copy the pattern 8 bytes at a time.
985 }
986 if (length & 1) { // Finish with left-over.
987 dst[i << 1] = src[i << 1];
988 }
989}
990
991static WEBP_INLINE void CopyBlock32b(uint32_t* const dst,
992 int dist, int length) {
993 const uint32_t* const src = dst - dist;
994 if (dist <= 2 && length >= 4 && ((uintptr_t)dst & 3) == 0) {
995 uint64_t pattern;
996 if (dist == 1) {
997 pattern = (uint64_t)src[0];
998 pattern |= pattern << 32;
999 } else {
1000 memcpy(&pattern, src, sizeof(pattern));
1001 }
1002 CopySmallPattern32b(src, dst, length, pattern);
1003 } else if (dist >= length) { // no overlap
1004 memcpy(dst, src, length * sizeof(*dst));
1005 } else {
1006 int i;
1007 for (i = 0; i < length; ++i) dst[i] = src[i];
1008 }
1009}
1010
1011//------------------------------------------------------------------------------
1012
1013static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
1014 int width, int height, int last_row) {
1015 int ok = 1;
1016 int row = dec->last_pixel_ / width;
1017 int col = dec->last_pixel_ % width;
1018 VP8LBitReader* const br = &dec->br_;
1019 VP8LMetadata* const hdr = &dec->hdr_;
1020 int pos = dec->last_pixel_; // current position
1021 const int end = width * height; // End of data
1022 const int last = width * last_row; // Last pixel to decode
1023 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1024 const int mask = hdr->huffman_mask_;
1025 const HTreeGroup* htree_group =
1026 (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1027 assert(pos <= end);
1028 assert(last_row <= height);
1029 assert(Is8bOptimizable(hdr));
1030
1031 while (!br->eos_ && pos < last) {
1032 int code;
1033 // Only update when changing tile.
1034 if ((col & mask) == 0) {
1035 htree_group = GetHtreeGroupForPos(hdr, col, row);
1036 }
1037 assert(htree_group != NULL);
1038 VP8LFillBitWindow(br);
1039 code = ReadSymbol(htree_group->htrees[GREEN], br);
1040 if (code < NUM_LITERAL_CODES) { // Literal
1041 data[pos] = code;
1042 ++pos;
1043 ++col;
1044 if (col >= width) {
1045 col = 0;
1046 ++row;
1047 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1048 ExtractPalettedAlphaRows(dec, row);
1049 }
1050 }
1051 } else if (code < len_code_limit) { // Backward reference
1052 int dist_code, dist;
1053 const int length_sym = code - NUM_LITERAL_CODES;
1054 const int length = GetCopyLength(length_sym, br);
1055 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1056 VP8LFillBitWindow(br);
1057 dist_code = GetCopyDistance(dist_symbol, br);
1058 dist = PlaneCodeToDistance(width, dist_code);
1059 if (pos >= dist && end - pos >= length) {
1060 CopyBlock8b(data + pos, dist, length);
1061 } else {
1062 ok = 0;
1063 goto End;
1064 }
1065 pos += length;
1066 col += length;
1067 while (col >= width) {
1068 col -= width;
1069 ++row;
1070 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1071 ExtractPalettedAlphaRows(dec, row);
1072 }
1073 }
1074 if (pos < last && (col & mask)) {
1075 htree_group = GetHtreeGroupForPos(hdr, col, row);
1076 }
1077 } else { // Not reached
1078 ok = 0;
1079 goto End;
1080 }
1081 br->eos_ = VP8LIsEndOfStream(br);
1082 }
1083 // Process the remaining rows corresponding to last row-block.
1084 ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row);
1085
1086 End:
1087 br->eos_ = VP8LIsEndOfStream(br);
1088 if (!ok || (br->eos_ && pos < end)) {
1089 ok = 0;
1090 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED
1091 : VP8_STATUS_BITSTREAM_ERROR;
1092 } else {
1093 dec->last_pixel_ = pos;
1094 }
1095 return ok;
1096}
1097
1098static void SaveState(VP8LDecoder* const dec, int last_pixel) {
1099 assert(dec->incremental_);
1100 dec->saved_br_ = dec->br_;
1101 dec->saved_last_pixel_ = last_pixel;
1102 if (dec->hdr_.color_cache_size_ > 0) {
1103 VP8LColorCacheCopy(&dec->hdr_.color_cache_, &dec->hdr_.saved_color_cache_);
1104 }
1105}
1106
1107static void RestoreState(VP8LDecoder* const dec) {
1108 assert(dec->br_.eos_);
1109 dec->status_ = VP8_STATUS_SUSPENDED;
1110 dec->br_ = dec->saved_br_;
1111 dec->last_pixel_ = dec->saved_last_pixel_;
1112 if (dec->hdr_.color_cache_size_ > 0) {
1113 VP8LColorCacheCopy(&dec->hdr_.saved_color_cache_, &dec->hdr_.color_cache_);
1114 }
1115}
1116
1117#define SYNC_EVERY_N_ROWS 8 // minimum number of rows between check-points
1118static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
1119 int width, int height, int last_row,
1120 ProcessRowsFunc process_func) {
1121 int row = dec->last_pixel_ / width;
1122 int col = dec->last_pixel_ % width;
1123 VP8LBitReader* const br = &dec->br_;
1124 VP8LMetadata* const hdr = &dec->hdr_;
1125 uint32_t* src = data + dec->last_pixel_;
1126 uint32_t* last_cached = src;
1127 uint32_t* const src_end = data + width * height; // End of data
1128 uint32_t* const src_last = data + width * last_row; // Last pixel to decode
1129 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1130 const int color_cache_limit = len_code_limit + hdr->color_cache_size_;
1131 int next_sync_row = dec->incremental_ ? row : 1 << 24;
1132 VP8LColorCache* const color_cache =
1133 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL;
1134 const int mask = hdr->huffman_mask_;
1135 const HTreeGroup* htree_group =
1136 (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1137 assert(dec->last_row_ < last_row);
1138 assert(src_last <= src_end);
1139
1140 while (src < src_last) {
1141 int code;
1142 if (row >= next_sync_row) {
1143 SaveState(dec, (int)(src - data));
1144 next_sync_row = row + SYNC_EVERY_N_ROWS;
1145 }
1146 // Only update when changing tile. Note we could use this test:
1147 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
1148 // but that's actually slower and needs storing the previous col/row.
1149 if ((col & mask) == 0) {
1150 htree_group = GetHtreeGroupForPos(hdr, col, row);
1151 }
1152 assert(htree_group != NULL);
1153 if (htree_group->is_trivial_code) {
1154 *src = htree_group->literal_arb;
1155 goto AdvanceByOne;
1156 }
1157 VP8LFillBitWindow(br);
1158 if (htree_group->use_packed_table) {
1159 code = ReadPackedSymbols(htree_group, br, src);
1160 if (VP8LIsEndOfStream(br)) break;
1161 if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne;
1162 } else {
1163 code = ReadSymbol(htree_group->htrees[GREEN], br);
1164 }
1165 if (VP8LIsEndOfStream(br)) break;
1166 if (code < NUM_LITERAL_CODES) { // Literal
1167 if (htree_group->is_trivial_literal) {
1168 *src = htree_group->literal_arb | (code << 8);
1169 } else {
1170 int red, blue, alpha;
1171 red = ReadSymbol(htree_group->htrees[RED], br);
1172 VP8LFillBitWindow(br);
1173 blue = ReadSymbol(htree_group->htrees[BLUE], br);
1174 alpha = ReadSymbol(htree_group->htrees[ALPHA], br);
1175 if (VP8LIsEndOfStream(br)) break;
1176 *src = ((uint32_t)alpha << 24) | (red << 16) | (code << 8) | blue;
1177 }
1178 AdvanceByOne:
1179 ++src;
1180 ++col;
1181 if (col >= width) {
1182 col = 0;
1183 ++row;
1184 if (process_func != NULL) {
1185 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1186 process_func(dec, row);
1187 }
1188 }
1189 if (color_cache != NULL) {
1190 while (last_cached < src) {
1191 VP8LColorCacheInsert(color_cache, *last_cached++);
1192 }
1193 }
1194 }
1195 } else if (code < len_code_limit) { // Backward reference
1196 int dist_code, dist;
1197 const int length_sym = code - NUM_LITERAL_CODES;
1198 const int length = GetCopyLength(length_sym, br);
1199 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1200 VP8LFillBitWindow(br);
1201 dist_code = GetCopyDistance(dist_symbol, br);
1202 dist = PlaneCodeToDistance(width, dist_code);
1203
1204 if (VP8LIsEndOfStream(br)) break;
1205 if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) {
1206 goto Error;
1207 } else {
1208 CopyBlock32b(src, dist, length);
1209 }
1210 src += length;
1211 col += length;
1212 while (col >= width) {
1213 col -= width;
1214 ++row;
1215 if (process_func != NULL) {
1216 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1217 process_func(dec, row);
1218 }
1219 }
1220 }
1221 // Because of the check done above (before 'src' was incremented by
1222 // 'length'), the following holds true.
1223 assert(src <= src_end);
1224 if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row);
1225 if (color_cache != NULL) {
1226 while (last_cached < src) {
1227 VP8LColorCacheInsert(color_cache, *last_cached++);
1228 }
1229 }
1230 } else if (code < color_cache_limit) { // Color cache
1231 const int key = code - len_code_limit;
1232 assert(color_cache != NULL);
1233 while (last_cached < src) {
1234 VP8LColorCacheInsert(color_cache, *last_cached++);
1235 }
1236 *src = VP8LColorCacheLookup(color_cache, key);
1237 goto AdvanceByOne;
1238 } else { // Not reached
1239 goto Error;
1240 }
1241 }
1242
1243 br->eos_ = VP8LIsEndOfStream(br);
1244 if (dec->incremental_ && br->eos_ && src < src_end) {
1245 RestoreState(dec);
1246 } else if (!br->eos_) {
1247 // Process the remaining rows corresponding to last row-block.
1248 if (process_func != NULL) {
1249 process_func(dec, row > last_row ? last_row : row);
1250 }
1251 dec->status_ = VP8_STATUS_OK;
1252 dec->last_pixel_ = (int)(src - data); // end-of-scan marker
1253 } else {
1254 // if not incremental, and we are past the end of buffer (eos_=1), then this
1255 // is a real bitstream error.
1256 goto Error;
1257 }
1258 return 1;
1259
1260 Error:
1261 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1262 return 0;
1263}
1264
1265// -----------------------------------------------------------------------------
1266// VP8LTransform
1267
1268static void ClearTransform(VP8LTransform* const transform) {
1269 WebPSafeFree(transform->data_);
1270 transform->data_ = NULL;
1271}
1272
1273// For security reason, we need to remap the color map to span
1274// the total possible bundled values, and not just the num_colors.
1275static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
1276 int i;
1277 const int final_num_colors = 1 << (8 >> transform->bits_);
1278 uint32_t* const new_color_map =
1279 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors,
1280 sizeof(*new_color_map));
1281 if (new_color_map == NULL) {
1282 return 0;
1283 } else {
1284 uint8_t* const data = (uint8_t*)transform->data_;
1285 uint8_t* const new_data = (uint8_t*)new_color_map;
1286 new_color_map[0] = transform->data_[0];
1287 for (i = 4; i < 4 * num_colors; ++i) {
1288 // Equivalent to VP8LAddPixels(), on a byte-basis.
1289 new_data[i] = (data[i] + new_data[i - 4]) & 0xff;
1290 }
1291 for (; i < 4 * final_num_colors; ++i) {
1292 new_data[i] = 0; // black tail.
1293 }
1294 WebPSafeFree(transform->data_);
1295 transform->data_ = new_color_map;
1296 }
1297 return 1;
1298}
1299
1300static int ReadTransform(int* const xsize, int const* ysize,
1301 VP8LDecoder* const dec) {
1302 int ok = 1;
1303 VP8LBitReader* const br = &dec->br_;
1304 VP8LTransform* transform = &dec->transforms_[dec->next_transform_];
1305 const VP8LImageTransformType type =
1306 (VP8LImageTransformType)VP8LReadBits(br, 2);
1307
1308 // Each transform type can only be present once in the stream.
1309 if (dec->transforms_seen_ & (1U << type)) {
1310 return 0; // Already there, let's not accept the second same transform.
1311 }
1312 dec->transforms_seen_ |= (1U << type);
1313
1314 transform->type_ = type;
1315 transform->xsize_ = *xsize;
1316 transform->ysize_ = *ysize;
1317 transform->data_ = NULL;
1318 ++dec->next_transform_;
1319 assert(dec->next_transform_ <= NUM_TRANSFORMS);
1320
1321 switch (type) {
1322 case PREDICTOR_TRANSFORM:
1323 case CROSS_COLOR_TRANSFORM:
1324 transform->bits_ = VP8LReadBits(br, 3) + 2;
1325 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
1326 transform->bits_),
1327 VP8LSubSampleSize(transform->ysize_,
1328 transform->bits_),
1329 0, dec, &transform->data_);
1330 break;
1331 case COLOR_INDEXING_TRANSFORM: {
1332 const int num_colors = VP8LReadBits(br, 8) + 1;
1333 const int bits = (num_colors > 16) ? 0
1334 : (num_colors > 4) ? 1
1335 : (num_colors > 2) ? 2
1336 : 3;
1337 *xsize = VP8LSubSampleSize(transform->xsize_, bits);
1338 transform->bits_ = bits;
1339 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_);
1340 ok = ok && ExpandColorMap(num_colors, transform);
1341 break;
1342 }
1343 case SUBTRACT_GREEN_TRANSFORM:
1344 break;
1345 default:
1346 assert(0); // can't happen
1347 break;
1348 }
1349
1350 return ok;
1351}
1352
1353// -----------------------------------------------------------------------------
1354// VP8LMetadata
1355
1356static void InitMetadata(VP8LMetadata* const hdr) {
1357 assert(hdr != NULL);
1358 memset(hdr, 0, sizeof(*hdr));
1359}
1360
1361static void ClearMetadata(VP8LMetadata* const hdr) {
1362 assert(hdr != NULL);
1363
1364 WebPSafeFree(hdr->huffman_image_);
1365 VP8LHuffmanTablesDeallocate(&hdr->huffman_tables_);
1366 VP8LHtreeGroupsFree(hdr->htree_groups_);
1367 VP8LColorCacheClear(&hdr->color_cache_);
1368 VP8LColorCacheClear(&hdr->saved_color_cache_);
1369 InitMetadata(hdr);
1370}
1371
1372// -----------------------------------------------------------------------------
1373// VP8LDecoder
1374
1375VP8LDecoder* VP8LNew(void) {
1376 VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
1377 if (dec == NULL) return NULL;
1378 dec->status_ = VP8_STATUS_OK;
1379 dec->state_ = READ_DIM;
1380
1381 VP8LDspInit(); // Init critical function pointers.
1382
1383 return dec;
1384}
1385
1386void VP8LClear(VP8LDecoder* const dec) {
1387 int i;
1388 if (dec == NULL) return;
1389 ClearMetadata(&dec->hdr_);
1390
1391 WebPSafeFree(dec->pixels_);
1392 dec->pixels_ = NULL;
1393 for (i = 0; i < dec->next_transform_; ++i) {
1394 ClearTransform(&dec->transforms_[i]);
1395 }
1396 dec->next_transform_ = 0;
1397 dec->transforms_seen_ = 0;
1398
1399 WebPSafeFree(dec->rescaler_memory);
1400 dec->rescaler_memory = NULL;
1401
1402 dec->output_ = NULL; // leave no trace behind
1403}
1404
1405void VP8LDelete(VP8LDecoder* const dec) {
1406 if (dec != NULL) {
1407 VP8LClear(dec);
1408 WebPSafeFree(dec);
1409 }
1410}
1411
1412static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) {
1413 VP8LMetadata* const hdr = &dec->hdr_;
1414 const int num_bits = hdr->huffman_subsample_bits_;
1415 dec->width_ = width;
1416 dec->height_ = height;
1417
1418 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits);
1419 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1;
1420}
1421
1422static int DecodeImageStream(int xsize, int ysize,
1423 int is_level0,
1424 VP8LDecoder* const dec,
1425 uint32_t** const decoded_data) {
1426 int ok = 1;
1427 int transform_xsize = xsize;
1428 int transform_ysize = ysize;
1429 VP8LBitReader* const br = &dec->br_;
1430 VP8LMetadata* const hdr = &dec->hdr_;
1431 uint32_t* data = NULL;
1432 int color_cache_bits = 0;
1433
1434 // Read the transforms (may recurse).
1435 if (is_level0) {
1436 while (ok && VP8LReadBits(br, 1)) {
1437 ok = ReadTransform(&transform_xsize, &transform_ysize, dec);
1438 }
1439 }
1440
1441 // Color cache
1442 if (ok && VP8LReadBits(br, 1)) {
1443 color_cache_bits = VP8LReadBits(br, 4);
1444 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS);
1445 if (!ok) {
1446 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1447 goto End;
1448 }
1449 }
1450
1451 // Read the Huffman codes (may recurse).
1452 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize,
1453 color_cache_bits, is_level0);
1454 if (!ok) {
1455 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1456 goto End;
1457 }
1458
1459 // Finish setting up the color-cache
1460 if (color_cache_bits > 0) {
1461 hdr->color_cache_size_ = 1 << color_cache_bits;
1462 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) {
1463 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1464 ok = 0;
1465 goto End;
1466 }
1467 } else {
1468 hdr->color_cache_size_ = 0;
1469 }
1470 UpdateDecoder(dec, transform_xsize, transform_ysize);
1471
1472 if (is_level0) { // level 0 complete
1473 dec->state_ = READ_HDR;
1474 goto End;
1475 }
1476
1477 {
1478 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize;
1479 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data));
1480 if (data == NULL) {
1481 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1482 ok = 0;
1483 goto End;
1484 }
1485 }
1486
1487 // Use the Huffman trees to decode the LZ77 encoded data.
1488 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize,
1489 transform_ysize, NULL);
1490 ok = ok && !br->eos_;
1491
1492 End:
1493 if (!ok) {
1494 WebPSafeFree(data);
1495 ClearMetadata(hdr);
1496 } else {
1497 if (decoded_data != NULL) {
1498 *decoded_data = data;
1499 } else {
1500 // We allocate image data in this function only for transforms. At level 0
1501 // (that is: not the transforms), we shouldn't have allocated anything.
1502 assert(data == NULL);
1503 assert(is_level0);
1504 }
1505 dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls.
1506 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind.
1507 }
1508 return ok;
1509}
1510
1511//------------------------------------------------------------------------------
1512// Allocate internal buffers dec->pixels_ and dec->argb_cache_.
1513static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) {
1514 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_;
1515 // Scratch buffer corresponding to top-prediction row for transforming the
1516 // first row in the row-blocks. Not needed for paletted alpha.
1517 const uint64_t cache_top_pixels = (uint16_t)final_width;
1518 // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
1519 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS;
1520 const uint64_t total_num_pixels =
1521 num_pixels + cache_top_pixels + cache_pixels;
1522
1523 assert(dec->width_ <= final_width);
1524 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t));
1525 if (dec->pixels_ == NULL) {
1526 dec->argb_cache_ = NULL; // for soundness
1527 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1528 return 0;
1529 }
1530 dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels;
1531 return 1;
1532}
1533
1534static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
1535 const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_;
1536 dec->argb_cache_ = NULL; // for soundness
1537 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t));
1538 if (dec->pixels_ == NULL) {
1539 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1540 return 0;
1541 }
1542 return 1;
1543}
1544
1545//------------------------------------------------------------------------------
1546
1547// Special row-processing that only stores the alpha data.
1548static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) {
1549 int cur_row = dec->last_row_;
1550 int num_rows = last_row - cur_row;
1551 const uint32_t* in = dec->pixels_ + dec->width_ * cur_row;
1552
1553 assert(last_row <= dec->io_->crop_bottom);
1554 while (num_rows > 0) {
1555 const int num_rows_to_process =
1556 (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows;
1557 // Extract alpha (which is stored in the green plane).
1558 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
1559 uint8_t* const output = alph_dec->output_;
1560 const int width = dec->io_->width; // the final width (!= dec->width_)
1561 const int cache_pixs = width * num_rows_to_process;
1562 uint8_t* const dst = output + width * cur_row;
1563 const uint32_t* const src = dec->argb_cache_;
1564 ApplyInverseTransforms(dec, cur_row, num_rows_to_process, in);
1565 WebPExtractGreen(src, dst, cache_pixs);
1566 AlphaApplyFilter(alph_dec,
1567 cur_row, cur_row + num_rows_to_process, dst, width);
1568 num_rows -= num_rows_to_process;
1569 in += num_rows_to_process * dec->width_;
1570 cur_row += num_rows_to_process;
1571 }
1572 assert(cur_row == last_row);
1573 dec->last_row_ = dec->last_out_row_ = last_row;
1574}
1575
1576int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
1577 const uint8_t* const data, size_t data_size) {
1578 int ok = 0;
1579 VP8LDecoder* dec = VP8LNew();
1580
1581 if (dec == NULL) return 0;
1582
1583 assert(alph_dec != NULL);
1584
1585 dec->width_ = alph_dec->width_;
1586 dec->height_ = alph_dec->height_;
1587 dec->io_ = &alph_dec->io_;
1588 dec->io_->opaque = alph_dec;
1589 dec->io_->width = alph_dec->width_;
1590 dec->io_->height = alph_dec->height_;
1591
1592 dec->status_ = VP8_STATUS_OK;
1593 VP8LInitBitReader(&dec->br_, data, data_size);
1594
1595 if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) {
1596 goto Err;
1597 }
1598
1599 // Special case: if alpha data uses only the color indexing transform and
1600 // doesn't use color cache (a frequent case), we will use DecodeAlphaData()
1601 // method that only needs allocation of 1 byte per pixel (alpha channel).
1602 if (dec->next_transform_ == 1 &&
1603 dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM &&
1604 Is8bOptimizable(&dec->hdr_)) {
1605 alph_dec->use_8b_decode_ = 1;
1606 ok = AllocateInternalBuffers8b(dec);
1607 } else {
1608 // Allocate internal buffers (note that dec->width_ may have changed here).
1609 alph_dec->use_8b_decode_ = 0;
1610 ok = AllocateInternalBuffers32b(dec, alph_dec->width_);
1611 }
1612
1613 if (!ok) goto Err;
1614
1615 // Only set here, once we are sure it is valid (to avoid thread races).
1616 alph_dec->vp8l_dec_ = dec;
1617 return 1;
1618
1619 Err:
1620 VP8LDelete(dec);
1621 return 0;
1622}
1623
1624int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) {
1625 VP8LDecoder* const dec = alph_dec->vp8l_dec_;
1626 assert(dec != NULL);
1627 assert(last_row <= dec->height_);
1628
1629 if (dec->last_row_ >= last_row) {
1630 return 1; // done
1631 }
1632
1633 if (!alph_dec->use_8b_decode_) WebPInitAlphaProcessing();
1634
1635 // Decode (with special row processing).
1636 return alph_dec->use_8b_decode_ ?
1637 DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
1638 last_row) :
1639 DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1640 last_row, ExtractAlphaRows);
1641}
1642
1643//------------------------------------------------------------------------------
1644
1645int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) {
1646 int width, height, has_alpha;
1647
1648 if (dec == NULL) return 0;
1649 if (io == NULL) {
1650 dec->status_ = VP8_STATUS_INVALID_PARAM;
1651 return 0;
1652 }
1653
1654 dec->io_ = io;
1655 dec->status_ = VP8_STATUS_OK;
1656 VP8LInitBitReader(&dec->br_, io->data, io->data_size);
1657 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) {
1658 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1659 goto Error;
1660 }
1661 dec->state_ = READ_DIM;
1662 io->width = width;
1663 io->height = height;
1664
1665 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error;
1666 return 1;
1667
1668 Error:
1669 VP8LClear(dec);
1670 assert(dec->status_ != VP8_STATUS_OK);
1671 return 0;
1672}
1673
1674int VP8LDecodeImage(VP8LDecoder* const dec) {
1675 VP8Io* io = NULL;
1676 WebPDecParams* params = NULL;
1677
1678 if (dec == NULL) return 0;
1679
1680 assert(dec->hdr_.huffman_tables_.root.start != NULL);
1681 assert(dec->hdr_.htree_groups_ != NULL);
1682 assert(dec->hdr_.num_htree_groups_ > 0);
1683
1684 io = dec->io_;
1685 assert(io != NULL);
1686 params = (WebPDecParams*)io->opaque;
1687 assert(params != NULL);
1688
1689 // Initialization.
1690 if (dec->state_ != READ_DATA) {
1691 dec->output_ = params->output;
1692 assert(dec->output_ != NULL);
1693
1694 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
1695 dec->status_ = VP8_STATUS_INVALID_PARAM;
1696 goto Err;
1697 }
1698
1699 if (!AllocateInternalBuffers32b(dec, io->width)) goto Err;
1700
1701#if !defined(WEBP_REDUCE_SIZE)
1702 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
1703#else
1704 if (io->use_scaling) {
1705 dec->status_ = VP8_STATUS_INVALID_PARAM;
1706 goto Err;
1707 }
1708#endif
1709 if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) {
1710 // need the alpha-multiply functions for premultiplied output or rescaling
1711 WebPInitAlphaProcessing();
1712 }
1713
1714 if (!WebPIsRGBMode(dec->output_->colorspace)) {
1715 WebPInitConvertARGBToYUV();
1716 if (dec->output_->u.YUVA.a != NULL) WebPInitAlphaProcessing();
1717 }
1718 if (dec->incremental_) {
1719 if (dec->hdr_.color_cache_size_ > 0 &&
1720 dec->hdr_.saved_color_cache_.colors_ == NULL) {
1721 if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_,
1722 dec->hdr_.color_cache_.hash_bits_)) {
1723 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1724 goto Err;
1725 }
1726 }
1727 }
1728 dec->state_ = READ_DATA;
1729 }
1730
1731 // Decode.
1732 if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1733 io->crop_bottom, ProcessRows)) {
1734 goto Err;
1735 }
1736
1737 params->last_y = dec->last_out_row_;
1738 return 1;
1739
1740 Err:
1741 VP8LClear(dec);
1742 assert(dec->status_ != VP8_STATUS_OK);
1743 return 0;
1744}
1745
1746//------------------------------------------------------------------------------
1747