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
29 static const int kCodeLengthLiterals = 16;
30 static const int kCodeLengthRepeatCode = 16;
31 static const uint8_t kCodeLengthExtraBits[3] = { 2, 3, 7 };
32 static 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.
41 typedef enum {
42 GREEN = 0,
43 RED = 1,
44 BLUE = 2,
45 ALPHA = 3,
46 DIST = 4
47 } HuffIndex;
48
49 static 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
55 static const uint8_t kLiteralMap[HUFFMAN_CODES_PER_META_CODE] = {
56 0, 1, 1, 1, 0
57 };
58
59 #define NUM_CODE_LENGTH_CODES 19
60 static 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
65 static 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)
89 static 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
104 static int DecodeImageStream(int xsize, int ysize,
105 int is_level0,
106 VP8LDecoder* const dec,
107 uint32_t** const decoded_data);
108
109 //------------------------------------------------------------------------------
110
VP8LCheckSignature(const uint8_t * const data,size_t size)111 int 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
ReadImageInfo(VP8LBitReader * const br,int * const width,int * const height,int * const has_alpha)117 static 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
VP8LGetInfo(const uint8_t * data,size_t data_size,int * const width,int * const height,int * const has_alpha)128 int 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
GetCopyDistance(int distance_symbol,VP8LBitReader * const br)150 static 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
GetCopyLength(int length_symbol,VP8LBitReader * const br)161 static 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
PlaneCodeToDistance(int xsize,int plane_code)167 static 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.
ReadSymbol(const HuffmanCode * table,VP8LBitReader * const br)183 static 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
ReadPackedSymbols(const HTreeGroup * group,VP8LBitReader * const br,uint32_t * const dst)202 static 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
AccumulateHCode(HuffmanCode hcode,int shift,HuffmanCode32 * const huff)219 static 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
BuildPackedTable(HTreeGroup * const htree_group)227 static 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
ReadHuffmanCodeLengths(VP8LDecoder * const dec,const int * const code_length_code_lengths,int num_symbols,int * const code_lengths)248 static 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.
ReadHuffmanCode(int alphabet_size,VP8LDecoder * const dec,int * const code_lengths,HuffmanCode * const table)309 static 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
ReadHuffmanCodes(VP8LDecoder * const dec,int xsize,int ysize,int color_cache_bits,int allow_recursion)358 static 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)
AllocateAndInitRescaler(VP8LDecoder * const dec,VP8Io * const io)535 static 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 if (!WebPRescalerInit(dec->rescaler, in_width, in_height,
563 (uint8_t*)scaled_data, out_width, out_height,
564 0, num_channels, work)) {
565 return 0;
566 }
567 return 1;
568 }
569 #endif // WEBP_REDUCE_SIZE
570
571 //------------------------------------------------------------------------------
572 // Export to ARGB
573
574 #if !defined(WEBP_REDUCE_SIZE)
575
576 // We have special "export" function since we need to convert from BGRA
Export(WebPRescaler * const rescaler,WEBP_CSP_MODE colorspace,int rgba_stride,uint8_t * const rgba)577 static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace,
578 int rgba_stride, uint8_t* const rgba) {
579 uint32_t* const src = (uint32_t*)rescaler->dst;
580 uint8_t* dst = rgba;
581 const int dst_width = rescaler->dst_width;
582 int num_lines_out = 0;
583 while (WebPRescalerHasPendingOutput(rescaler)) {
584 WebPRescalerExportRow(rescaler);
585 WebPMultARGBRow(src, dst_width, 1);
586 VP8LConvertFromBGRA(src, dst_width, colorspace, dst);
587 dst += rgba_stride;
588 ++num_lines_out;
589 }
590 return num_lines_out;
591 }
592
593 // Emit scaled rows.
EmitRescaledRowsRGBA(const VP8LDecoder * const dec,uint8_t * in,int in_stride,int mb_h,uint8_t * const out,int out_stride)594 static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec,
595 uint8_t* in, int in_stride, int mb_h,
596 uint8_t* const out, int out_stride) {
597 const WEBP_CSP_MODE colorspace = dec->output_->colorspace;
598 int num_lines_in = 0;
599 int num_lines_out = 0;
600 while (num_lines_in < mb_h) {
601 uint8_t* const row_in = in + (uint64_t)num_lines_in * in_stride;
602 uint8_t* const row_out = out + (uint64_t)num_lines_out * out_stride;
603 const int lines_left = mb_h - num_lines_in;
604 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
605 int lines_imported;
606 assert(needed_lines > 0 && needed_lines <= lines_left);
607 WebPMultARGBRows(row_in, in_stride,
608 dec->rescaler->src_width, needed_lines, 0);
609 lines_imported =
610 WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride);
611 assert(lines_imported == needed_lines);
612 num_lines_in += lines_imported;
613 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out);
614 }
615 return num_lines_out;
616 }
617
618 #endif // WEBP_REDUCE_SIZE
619
620 // Emit rows without any scaling.
EmitRows(WEBP_CSP_MODE colorspace,const uint8_t * row_in,int in_stride,int mb_w,int mb_h,uint8_t * const out,int out_stride)621 static int EmitRows(WEBP_CSP_MODE colorspace,
622 const uint8_t* row_in, int in_stride,
623 int mb_w, int mb_h,
624 uint8_t* const out, int out_stride) {
625 int lines = mb_h;
626 uint8_t* row_out = out;
627 while (lines-- > 0) {
628 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out);
629 row_in += in_stride;
630 row_out += out_stride;
631 }
632 return mb_h; // Num rows out == num rows in.
633 }
634
635 //------------------------------------------------------------------------------
636 // Export to YUVA
637
ConvertToYUVA(const uint32_t * const src,int width,int y_pos,const WebPDecBuffer * const output)638 static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos,
639 const WebPDecBuffer* const output) {
640 const WebPYUVABuffer* const buf = &output->u.YUVA;
641
642 // first, the luma plane
643 WebPConvertARGBToY(src, buf->y + y_pos * buf->y_stride, width);
644
645 // then U/V planes
646 {
647 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride;
648 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride;
649 // even lines: store values
650 // odd lines: average with previous values
651 WebPConvertARGBToUV(src, u, v, width, !(y_pos & 1));
652 }
653 // Lastly, store alpha if needed.
654 if (buf->a != NULL) {
655 uint8_t* const a = buf->a + y_pos * buf->a_stride;
656 #if defined(WORDS_BIGENDIAN)
657 WebPExtractAlpha((uint8_t*)src + 0, 0, width, 1, a, 0);
658 #else
659 WebPExtractAlpha((uint8_t*)src + 3, 0, width, 1, a, 0);
660 #endif
661 }
662 }
663
ExportYUVA(const VP8LDecoder * const dec,int y_pos)664 static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) {
665 WebPRescaler* const rescaler = dec->rescaler;
666 uint32_t* const src = (uint32_t*)rescaler->dst;
667 const int dst_width = rescaler->dst_width;
668 int num_lines_out = 0;
669 while (WebPRescalerHasPendingOutput(rescaler)) {
670 WebPRescalerExportRow(rescaler);
671 WebPMultARGBRow(src, dst_width, 1);
672 ConvertToYUVA(src, dst_width, y_pos, dec->output_);
673 ++y_pos;
674 ++num_lines_out;
675 }
676 return num_lines_out;
677 }
678
EmitRescaledRowsYUVA(const VP8LDecoder * const dec,uint8_t * in,int in_stride,int mb_h)679 static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec,
680 uint8_t* in, int in_stride, int mb_h) {
681 int num_lines_in = 0;
682 int y_pos = dec->last_out_row_;
683 while (num_lines_in < mb_h) {
684 const int lines_left = mb_h - num_lines_in;
685 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
686 int lines_imported;
687 WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0);
688 lines_imported =
689 WebPRescalerImport(dec->rescaler, lines_left, in, in_stride);
690 assert(lines_imported == needed_lines);
691 num_lines_in += lines_imported;
692 in += needed_lines * in_stride;
693 y_pos += ExportYUVA(dec, y_pos);
694 }
695 return y_pos;
696 }
697
EmitRowsYUVA(const VP8LDecoder * const dec,const uint8_t * in,int in_stride,int mb_w,int num_rows)698 static int EmitRowsYUVA(const VP8LDecoder* const dec,
699 const uint8_t* in, int in_stride,
700 int mb_w, int num_rows) {
701 int y_pos = dec->last_out_row_;
702 while (num_rows-- > 0) {
703 ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_);
704 in += in_stride;
705 ++y_pos;
706 }
707 return y_pos;
708 }
709
710 //------------------------------------------------------------------------------
711 // Cropping.
712
713 // Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and
714 // crop options. Also updates the input data pointer, so that it points to the
715 // start of the cropped window. Note that pixels are in ARGB format even if
716 // 'in_data' is uint8_t*.
717 // Returns true if the crop window is not empty.
SetCropWindow(VP8Io * const io,int y_start,int y_end,uint8_t ** const in_data,int pixel_stride)718 static int SetCropWindow(VP8Io* const io, int y_start, int y_end,
719 uint8_t** const in_data, int pixel_stride) {
720 assert(y_start < y_end);
721 assert(io->crop_left < io->crop_right);
722 if (y_end > io->crop_bottom) {
723 y_end = io->crop_bottom; // make sure we don't overflow on last row.
724 }
725 if (y_start < io->crop_top) {
726 const int delta = io->crop_top - y_start;
727 y_start = io->crop_top;
728 *in_data += delta * pixel_stride;
729 }
730 if (y_start >= y_end) return 0; // Crop window is empty.
731
732 *in_data += io->crop_left * sizeof(uint32_t);
733
734 io->mb_y = y_start - io->crop_top;
735 io->mb_w = io->crop_right - io->crop_left;
736 io->mb_h = y_end - y_start;
737 return 1; // Non-empty crop window.
738 }
739
740 //------------------------------------------------------------------------------
741
GetMetaIndex(const uint32_t * const image,int xsize,int bits,int x,int y)742 static WEBP_INLINE int GetMetaIndex(
743 const uint32_t* const image, int xsize, int bits, int x, int y) {
744 if (bits == 0) return 0;
745 return image[xsize * (y >> bits) + (x >> bits)];
746 }
747
GetHtreeGroupForPos(VP8LMetadata * const hdr,int x,int y)748 static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr,
749 int x, int y) {
750 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_,
751 hdr->huffman_subsample_bits_, x, y);
752 assert(meta_index < hdr->num_htree_groups_);
753 return hdr->htree_groups_ + meta_index;
754 }
755
756 //------------------------------------------------------------------------------
757 // Main loop, with custom row-processing function
758
759 typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row);
760
ApplyInverseTransforms(VP8LDecoder * const dec,int start_row,int num_rows,const uint32_t * const rows)761 static void ApplyInverseTransforms(VP8LDecoder* const dec,
762 int start_row, int num_rows,
763 const uint32_t* const rows) {
764 int n = dec->next_transform_;
765 const int cache_pixs = dec->width_ * num_rows;
766 const int end_row = start_row + num_rows;
767 const uint32_t* rows_in = rows;
768 uint32_t* const rows_out = dec->argb_cache_;
769
770 // Inverse transforms.
771 while (n-- > 0) {
772 VP8LTransform* const transform = &dec->transforms_[n];
773 VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out);
774 rows_in = rows_out;
775 }
776 if (rows_in != rows_out) {
777 // No transform called, hence just copy.
778 memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
779 }
780 }
781
782 // Processes (transforms, scales & color-converts) the rows decoded after the
783 // last call.
ProcessRows(VP8LDecoder * const dec,int row)784 static void ProcessRows(VP8LDecoder* const dec, int row) {
785 const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_;
786 const int num_rows = row - dec->last_row_;
787
788 assert(row <= dec->io_->crop_bottom);
789 // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size
790 // of argb_cache_), but we currently don't need more than that.
791 assert(num_rows <= NUM_ARGB_CACHE_ROWS);
792 if (num_rows > 0) { // Emit output.
793 VP8Io* const io = dec->io_;
794 uint8_t* rows_data = (uint8_t*)dec->argb_cache_;
795 const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA
796 ApplyInverseTransforms(dec, dec->last_row_, num_rows, rows);
797 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
798 // Nothing to output (this time).
799 } else {
800 const WebPDecBuffer* const output = dec->output_;
801 if (WebPIsRGBMode(output->colorspace)) { // convert to RGBA
802 const WebPRGBABuffer* const buf = &output->u.RGBA;
803 uint8_t* const rgba =
804 buf->rgba + (int64_t)dec->last_out_row_ * buf->stride;
805 const int num_rows_out =
806 #if !defined(WEBP_REDUCE_SIZE)
807 io->use_scaling ?
808 EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h,
809 rgba, buf->stride) :
810 #endif // WEBP_REDUCE_SIZE
811 EmitRows(output->colorspace, rows_data, in_stride,
812 io->mb_w, io->mb_h, rgba, buf->stride);
813 // Update 'last_out_row_'.
814 dec->last_out_row_ += num_rows_out;
815 } else { // convert to YUVA
816 dec->last_out_row_ = io->use_scaling ?
817 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) :
818 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h);
819 }
820 assert(dec->last_out_row_ <= output->height);
821 }
822 }
823
824 // Update 'last_row_'.
825 dec->last_row_ = row;
826 assert(dec->last_row_ <= dec->height_);
827 }
828
829 // Row-processing for the special case when alpha data contains only one
830 // transform (color indexing), and trivial non-green literals.
Is8bOptimizable(const VP8LMetadata * const hdr)831 static int Is8bOptimizable(const VP8LMetadata* const hdr) {
832 int i;
833 if (hdr->color_cache_size_ > 0) return 0;
834 // When the Huffman tree contains only one symbol, we can skip the
835 // call to ReadSymbol() for red/blue/alpha channels.
836 for (i = 0; i < hdr->num_htree_groups_; ++i) {
837 HuffmanCode** const htrees = hdr->htree_groups_[i].htrees;
838 if (htrees[RED][0].bits > 0) return 0;
839 if (htrees[BLUE][0].bits > 0) return 0;
840 if (htrees[ALPHA][0].bits > 0) return 0;
841 }
842 return 1;
843 }
844
AlphaApplyFilter(ALPHDecoder * const alph_dec,int first_row,int last_row,uint8_t * out,int stride)845 static void AlphaApplyFilter(ALPHDecoder* const alph_dec,
846 int first_row, int last_row,
847 uint8_t* out, int stride) {
848 if (alph_dec->filter_ != WEBP_FILTER_NONE) {
849 int y;
850 const uint8_t* prev_line = alph_dec->prev_line_;
851 assert(WebPUnfilters[alph_dec->filter_] != NULL);
852 for (y = first_row; y < last_row; ++y) {
853 WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride);
854 prev_line = out;
855 out += stride;
856 }
857 alph_dec->prev_line_ = prev_line;
858 }
859 }
860
ExtractPalettedAlphaRows(VP8LDecoder * const dec,int last_row)861 static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) {
862 // For vertical and gradient filtering, we need to decode the part above the
863 // crop_top row, in order to have the correct spatial predictors.
864 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
865 const int top_row =
866 (alph_dec->filter_ == WEBP_FILTER_NONE ||
867 alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top
868 : dec->last_row_;
869 const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_;
870 assert(last_row <= dec->io_->crop_bottom);
871 if (last_row > first_row) {
872 // Special method for paletted alpha data. We only process the cropped area.
873 const int width = dec->io_->width;
874 uint8_t* out = alph_dec->output_ + width * first_row;
875 const uint8_t* const in =
876 (uint8_t*)dec->pixels_ + dec->width_ * first_row;
877 VP8LTransform* const transform = &dec->transforms_[0];
878 assert(dec->next_transform_ == 1);
879 assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
880 VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row,
881 in, out);
882 AlphaApplyFilter(alph_dec, first_row, last_row, out, width);
883 }
884 dec->last_row_ = dec->last_out_row_ = last_row;
885 }
886
887 //------------------------------------------------------------------------------
888 // Helper functions for fast pattern copy (8b and 32b)
889
890 // cyclic rotation of pattern word
Rotate8b(uint32_t V)891 static WEBP_INLINE uint32_t Rotate8b(uint32_t V) {
892 #if defined(WORDS_BIGENDIAN)
893 return ((V & 0xff000000u) >> 24) | (V << 8);
894 #else
895 return ((V & 0xffu) << 24) | (V >> 8);
896 #endif
897 }
898
899 // copy 1, 2 or 4-bytes pattern
CopySmallPattern8b(const uint8_t * src,uint8_t * dst,int length,uint32_t pattern)900 static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst,
901 int length, uint32_t pattern) {
902 int i;
903 // align 'dst' to 4-bytes boundary. Adjust the pattern along the way.
904 while ((uintptr_t)dst & 3) {
905 *dst++ = *src++;
906 pattern = Rotate8b(pattern);
907 --length;
908 }
909 // Copy the pattern 4 bytes at a time.
910 for (i = 0; i < (length >> 2); ++i) {
911 ((uint32_t*)dst)[i] = pattern;
912 }
913 // Finish with left-overs. 'pattern' is still correctly positioned,
914 // so no Rotate8b() call is needed.
915 for (i <<= 2; i < length; ++i) {
916 dst[i] = src[i];
917 }
918 }
919
CopyBlock8b(uint8_t * const dst,int dist,int length)920 static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
921 const uint8_t* src = dst - dist;
922 if (length >= 8) {
923 uint32_t pattern = 0;
924 switch (dist) {
925 case 1:
926 pattern = src[0];
927 #if defined(__arm__) || defined(_M_ARM) // arm doesn't like multiply that much
928 pattern |= pattern << 8;
929 pattern |= pattern << 16;
930 #elif defined(WEBP_USE_MIPS_DSP_R2)
931 __asm__ volatile ("replv.qb %0, %0" : "+r"(pattern));
932 #else
933 pattern = 0x01010101u * pattern;
934 #endif
935 break;
936 case 2:
937 #if !defined(WORDS_BIGENDIAN)
938 memcpy(&pattern, src, sizeof(uint16_t));
939 #else
940 pattern = ((uint32_t)src[0] << 8) | src[1];
941 #endif
942 #if defined(__arm__) || defined(_M_ARM)
943 pattern |= pattern << 16;
944 #elif defined(WEBP_USE_MIPS_DSP_R2)
945 __asm__ volatile ("replv.ph %0, %0" : "+r"(pattern));
946 #else
947 pattern = 0x00010001u * pattern;
948 #endif
949 break;
950 case 4:
951 memcpy(&pattern, src, sizeof(uint32_t));
952 break;
953 default:
954 goto Copy;
955 }
956 CopySmallPattern8b(src, dst, length, pattern);
957 return;
958 }
959 Copy:
960 if (dist >= length) { // no overlap -> use memcpy()
961 memcpy(dst, src, length * sizeof(*dst));
962 } else {
963 int i;
964 for (i = 0; i < length; ++i) dst[i] = src[i];
965 }
966 }
967
968 // copy pattern of 1 or 2 uint32_t's
CopySmallPattern32b(const uint32_t * src,uint32_t * dst,int length,uint64_t pattern)969 static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src,
970 uint32_t* dst,
971 int length, uint64_t pattern) {
972 int i;
973 if ((uintptr_t)dst & 4) { // Align 'dst' to 8-bytes boundary.
974 *dst++ = *src++;
975 pattern = (pattern >> 32) | (pattern << 32);
976 --length;
977 }
978 assert(0 == ((uintptr_t)dst & 7));
979 for (i = 0; i < (length >> 1); ++i) {
980 ((uint64_t*)dst)[i] = pattern; // Copy the pattern 8 bytes at a time.
981 }
982 if (length & 1) { // Finish with left-over.
983 dst[i << 1] = src[i << 1];
984 }
985 }
986
CopyBlock32b(uint32_t * const dst,int dist,int length)987 static WEBP_INLINE void CopyBlock32b(uint32_t* const dst,
988 int dist, int length) {
989 const uint32_t* const src = dst - dist;
990 if (dist <= 2 && length >= 4 && ((uintptr_t)dst & 3) == 0) {
991 uint64_t pattern;
992 if (dist == 1) {
993 pattern = (uint64_t)src[0];
994 pattern |= pattern << 32;
995 } else {
996 memcpy(&pattern, src, sizeof(pattern));
997 }
998 CopySmallPattern32b(src, dst, length, pattern);
999 } else if (dist >= length) { // no overlap
1000 memcpy(dst, src, length * sizeof(*dst));
1001 } else {
1002 int i;
1003 for (i = 0; i < length; ++i) dst[i] = src[i];
1004 }
1005 }
1006
1007 //------------------------------------------------------------------------------
1008
DecodeAlphaData(VP8LDecoder * const dec,uint8_t * const data,int width,int height,int last_row)1009 static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
1010 int width, int height, int last_row) {
1011 int ok = 1;
1012 int row = dec->last_pixel_ / width;
1013 int col = dec->last_pixel_ % width;
1014 VP8LBitReader* const br = &dec->br_;
1015 VP8LMetadata* const hdr = &dec->hdr_;
1016 int pos = dec->last_pixel_; // current position
1017 const int end = width * height; // End of data
1018 const int last = width * last_row; // Last pixel to decode
1019 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1020 const int mask = hdr->huffman_mask_;
1021 const HTreeGroup* htree_group =
1022 (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1023 assert(pos <= end);
1024 assert(last_row <= height);
1025 assert(Is8bOptimizable(hdr));
1026
1027 while (!br->eos_ && pos < last) {
1028 int code;
1029 // Only update when changing tile.
1030 if ((col & mask) == 0) {
1031 htree_group = GetHtreeGroupForPos(hdr, col, row);
1032 }
1033 assert(htree_group != NULL);
1034 VP8LFillBitWindow(br);
1035 code = ReadSymbol(htree_group->htrees[GREEN], br);
1036 if (code < NUM_LITERAL_CODES) { // Literal
1037 data[pos] = code;
1038 ++pos;
1039 ++col;
1040 if (col >= width) {
1041 col = 0;
1042 ++row;
1043 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1044 ExtractPalettedAlphaRows(dec, row);
1045 }
1046 }
1047 } else if (code < len_code_limit) { // Backward reference
1048 int dist_code, dist;
1049 const int length_sym = code - NUM_LITERAL_CODES;
1050 const int length = GetCopyLength(length_sym, br);
1051 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1052 VP8LFillBitWindow(br);
1053 dist_code = GetCopyDistance(dist_symbol, br);
1054 dist = PlaneCodeToDistance(width, dist_code);
1055 if (pos >= dist && end - pos >= length) {
1056 CopyBlock8b(data + pos, dist, length);
1057 } else {
1058 ok = 0;
1059 goto End;
1060 }
1061 pos += length;
1062 col += length;
1063 while (col >= width) {
1064 col -= width;
1065 ++row;
1066 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1067 ExtractPalettedAlphaRows(dec, row);
1068 }
1069 }
1070 if (pos < last && (col & mask)) {
1071 htree_group = GetHtreeGroupForPos(hdr, col, row);
1072 }
1073 } else { // Not reached
1074 ok = 0;
1075 goto End;
1076 }
1077 br->eos_ = VP8LIsEndOfStream(br);
1078 }
1079 // Process the remaining rows corresponding to last row-block.
1080 ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row);
1081
1082 End:
1083 br->eos_ = VP8LIsEndOfStream(br);
1084 if (!ok || (br->eos_ && pos < end)) {
1085 ok = 0;
1086 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED
1087 : VP8_STATUS_BITSTREAM_ERROR;
1088 } else {
1089 dec->last_pixel_ = pos;
1090 }
1091 return ok;
1092 }
1093
SaveState(VP8LDecoder * const dec,int last_pixel)1094 static void SaveState(VP8LDecoder* const dec, int last_pixel) {
1095 assert(dec->incremental_);
1096 dec->saved_br_ = dec->br_;
1097 dec->saved_last_pixel_ = last_pixel;
1098 if (dec->hdr_.color_cache_size_ > 0) {
1099 VP8LColorCacheCopy(&dec->hdr_.color_cache_, &dec->hdr_.saved_color_cache_);
1100 }
1101 }
1102
RestoreState(VP8LDecoder * const dec)1103 static void RestoreState(VP8LDecoder* const dec) {
1104 assert(dec->br_.eos_);
1105 dec->status_ = VP8_STATUS_SUSPENDED;
1106 dec->br_ = dec->saved_br_;
1107 dec->last_pixel_ = dec->saved_last_pixel_;
1108 if (dec->hdr_.color_cache_size_ > 0) {
1109 VP8LColorCacheCopy(&dec->hdr_.saved_color_cache_, &dec->hdr_.color_cache_);
1110 }
1111 }
1112
1113 #define SYNC_EVERY_N_ROWS 8 // minimum number of rows between check-points
DecodeImageData(VP8LDecoder * const dec,uint32_t * const data,int width,int height,int last_row,ProcessRowsFunc process_func)1114 static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
1115 int width, int height, int last_row,
1116 ProcessRowsFunc process_func) {
1117 int row = dec->last_pixel_ / width;
1118 int col = dec->last_pixel_ % width;
1119 VP8LBitReader* const br = &dec->br_;
1120 VP8LMetadata* const hdr = &dec->hdr_;
1121 uint32_t* src = data + dec->last_pixel_;
1122 uint32_t* last_cached = src;
1123 uint32_t* const src_end = data + width * height; // End of data
1124 uint32_t* const src_last = data + width * last_row; // Last pixel to decode
1125 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
1126 const int color_cache_limit = len_code_limit + hdr->color_cache_size_;
1127 int next_sync_row = dec->incremental_ ? row : 1 << 24;
1128 VP8LColorCache* const color_cache =
1129 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL;
1130 const int mask = hdr->huffman_mask_;
1131 const HTreeGroup* htree_group =
1132 (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
1133 assert(dec->last_row_ < last_row);
1134 assert(src_last <= src_end);
1135
1136 while (src < src_last) {
1137 int code;
1138 if (row >= next_sync_row) {
1139 SaveState(dec, (int)(src - data));
1140 next_sync_row = row + SYNC_EVERY_N_ROWS;
1141 }
1142 // Only update when changing tile. Note we could use this test:
1143 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
1144 // but that's actually slower and needs storing the previous col/row.
1145 if ((col & mask) == 0) {
1146 htree_group = GetHtreeGroupForPos(hdr, col, row);
1147 }
1148 assert(htree_group != NULL);
1149 if (htree_group->is_trivial_code) {
1150 *src = htree_group->literal_arb;
1151 goto AdvanceByOne;
1152 }
1153 VP8LFillBitWindow(br);
1154 if (htree_group->use_packed_table) {
1155 code = ReadPackedSymbols(htree_group, br, src);
1156 if (VP8LIsEndOfStream(br)) break;
1157 if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne;
1158 } else {
1159 code = ReadSymbol(htree_group->htrees[GREEN], br);
1160 }
1161 if (VP8LIsEndOfStream(br)) break;
1162 if (code < NUM_LITERAL_CODES) { // Literal
1163 if (htree_group->is_trivial_literal) {
1164 *src = htree_group->literal_arb | (code << 8);
1165 } else {
1166 int red, blue, alpha;
1167 red = ReadSymbol(htree_group->htrees[RED], br);
1168 VP8LFillBitWindow(br);
1169 blue = ReadSymbol(htree_group->htrees[BLUE], br);
1170 alpha = ReadSymbol(htree_group->htrees[ALPHA], br);
1171 if (VP8LIsEndOfStream(br)) break;
1172 *src = ((uint32_t)alpha << 24) | (red << 16) | (code << 8) | blue;
1173 }
1174 AdvanceByOne:
1175 ++src;
1176 ++col;
1177 if (col >= width) {
1178 col = 0;
1179 ++row;
1180 if (process_func != NULL) {
1181 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1182 process_func(dec, row);
1183 }
1184 }
1185 if (color_cache != NULL) {
1186 while (last_cached < src) {
1187 VP8LColorCacheInsert(color_cache, *last_cached++);
1188 }
1189 }
1190 }
1191 } else if (code < len_code_limit) { // Backward reference
1192 int dist_code, dist;
1193 const int length_sym = code - NUM_LITERAL_CODES;
1194 const int length = GetCopyLength(length_sym, br);
1195 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
1196 VP8LFillBitWindow(br);
1197 dist_code = GetCopyDistance(dist_symbol, br);
1198 dist = PlaneCodeToDistance(width, dist_code);
1199
1200 if (VP8LIsEndOfStream(br)) break;
1201 if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) {
1202 goto Error;
1203 } else {
1204 CopyBlock32b(src, dist, length);
1205 }
1206 src += length;
1207 col += length;
1208 while (col >= width) {
1209 col -= width;
1210 ++row;
1211 if (process_func != NULL) {
1212 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
1213 process_func(dec, row);
1214 }
1215 }
1216 }
1217 // Because of the check done above (before 'src' was incremented by
1218 // 'length'), the following holds true.
1219 assert(src <= src_end);
1220 if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row);
1221 if (color_cache != NULL) {
1222 while (last_cached < src) {
1223 VP8LColorCacheInsert(color_cache, *last_cached++);
1224 }
1225 }
1226 } else if (code < color_cache_limit) { // Color cache
1227 const int key = code - len_code_limit;
1228 assert(color_cache != NULL);
1229 while (last_cached < src) {
1230 VP8LColorCacheInsert(color_cache, *last_cached++);
1231 }
1232 *src = VP8LColorCacheLookup(color_cache, key);
1233 goto AdvanceByOne;
1234 } else { // Not reached
1235 goto Error;
1236 }
1237 }
1238
1239 br->eos_ = VP8LIsEndOfStream(br);
1240 if (dec->incremental_ && br->eos_ && src < src_end) {
1241 RestoreState(dec);
1242 } else if (!br->eos_) {
1243 // Process the remaining rows corresponding to last row-block.
1244 if (process_func != NULL) {
1245 process_func(dec, row > last_row ? last_row : row);
1246 }
1247 dec->status_ = VP8_STATUS_OK;
1248 dec->last_pixel_ = (int)(src - data); // end-of-scan marker
1249 } else {
1250 // if not incremental, and we are past the end of buffer (eos_=1), then this
1251 // is a real bitstream error.
1252 goto Error;
1253 }
1254 return 1;
1255
1256 Error:
1257 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1258 return 0;
1259 }
1260
1261 // -----------------------------------------------------------------------------
1262 // VP8LTransform
1263
ClearTransform(VP8LTransform * const transform)1264 static void ClearTransform(VP8LTransform* const transform) {
1265 WebPSafeFree(transform->data_);
1266 transform->data_ = NULL;
1267 }
1268
1269 // For security reason, we need to remap the color map to span
1270 // the total possible bundled values, and not just the num_colors.
ExpandColorMap(int num_colors,VP8LTransform * const transform)1271 static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
1272 int i;
1273 const int final_num_colors = 1 << (8 >> transform->bits_);
1274 uint32_t* const new_color_map =
1275 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors,
1276 sizeof(*new_color_map));
1277 if (new_color_map == NULL) {
1278 return 0;
1279 } else {
1280 uint8_t* const data = (uint8_t*)transform->data_;
1281 uint8_t* const new_data = (uint8_t*)new_color_map;
1282 new_color_map[0] = transform->data_[0];
1283 for (i = 4; i < 4 * num_colors; ++i) {
1284 // Equivalent to AddPixelEq(), on a byte-basis.
1285 new_data[i] = (data[i] + new_data[i - 4]) & 0xff;
1286 }
1287 for (; i < 4 * final_num_colors; ++i) {
1288 new_data[i] = 0; // black tail.
1289 }
1290 WebPSafeFree(transform->data_);
1291 transform->data_ = new_color_map;
1292 }
1293 return 1;
1294 }
1295
ReadTransform(int * const xsize,int const * ysize,VP8LDecoder * const dec)1296 static int ReadTransform(int* const xsize, int const* ysize,
1297 VP8LDecoder* const dec) {
1298 int ok = 1;
1299 VP8LBitReader* const br = &dec->br_;
1300 VP8LTransform* transform = &dec->transforms_[dec->next_transform_];
1301 const VP8LImageTransformType type =
1302 (VP8LImageTransformType)VP8LReadBits(br, 2);
1303
1304 // Each transform type can only be present once in the stream.
1305 if (dec->transforms_seen_ & (1U << type)) {
1306 return 0; // Already there, let's not accept the second same transform.
1307 }
1308 dec->transforms_seen_ |= (1U << type);
1309
1310 transform->type_ = type;
1311 transform->xsize_ = *xsize;
1312 transform->ysize_ = *ysize;
1313 transform->data_ = NULL;
1314 ++dec->next_transform_;
1315 assert(dec->next_transform_ <= NUM_TRANSFORMS);
1316
1317 switch (type) {
1318 case PREDICTOR_TRANSFORM:
1319 case CROSS_COLOR_TRANSFORM:
1320 transform->bits_ = VP8LReadBits(br, 3) + 2;
1321 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
1322 transform->bits_),
1323 VP8LSubSampleSize(transform->ysize_,
1324 transform->bits_),
1325 0, dec, &transform->data_);
1326 break;
1327 case COLOR_INDEXING_TRANSFORM: {
1328 const int num_colors = VP8LReadBits(br, 8) + 1;
1329 const int bits = (num_colors > 16) ? 0
1330 : (num_colors > 4) ? 1
1331 : (num_colors > 2) ? 2
1332 : 3;
1333 *xsize = VP8LSubSampleSize(transform->xsize_, bits);
1334 transform->bits_ = bits;
1335 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_);
1336 ok = ok && ExpandColorMap(num_colors, transform);
1337 break;
1338 }
1339 case SUBTRACT_GREEN:
1340 break;
1341 default:
1342 assert(0); // can't happen
1343 break;
1344 }
1345
1346 return ok;
1347 }
1348
1349 // -----------------------------------------------------------------------------
1350 // VP8LMetadata
1351
InitMetadata(VP8LMetadata * const hdr)1352 static void InitMetadata(VP8LMetadata* const hdr) {
1353 assert(hdr != NULL);
1354 memset(hdr, 0, sizeof(*hdr));
1355 }
1356
ClearMetadata(VP8LMetadata * const hdr)1357 static void ClearMetadata(VP8LMetadata* const hdr) {
1358 assert(hdr != NULL);
1359
1360 WebPSafeFree(hdr->huffman_image_);
1361 WebPSafeFree(hdr->huffman_tables_);
1362 VP8LHtreeGroupsFree(hdr->htree_groups_);
1363 VP8LColorCacheClear(&hdr->color_cache_);
1364 VP8LColorCacheClear(&hdr->saved_color_cache_);
1365 InitMetadata(hdr);
1366 }
1367
1368 // -----------------------------------------------------------------------------
1369 // VP8LDecoder
1370
VP8LNew(void)1371 VP8LDecoder* VP8LNew(void) {
1372 VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
1373 if (dec == NULL) return NULL;
1374 dec->status_ = VP8_STATUS_OK;
1375 dec->state_ = READ_DIM;
1376
1377 VP8LDspInit(); // Init critical function pointers.
1378
1379 return dec;
1380 }
1381
VP8LClear(VP8LDecoder * const dec)1382 void VP8LClear(VP8LDecoder* const dec) {
1383 int i;
1384 if (dec == NULL) return;
1385 ClearMetadata(&dec->hdr_);
1386
1387 WebPSafeFree(dec->pixels_);
1388 dec->pixels_ = NULL;
1389 for (i = 0; i < dec->next_transform_; ++i) {
1390 ClearTransform(&dec->transforms_[i]);
1391 }
1392 dec->next_transform_ = 0;
1393 dec->transforms_seen_ = 0;
1394
1395 WebPSafeFree(dec->rescaler_memory);
1396 dec->rescaler_memory = NULL;
1397
1398 dec->output_ = NULL; // leave no trace behind
1399 }
1400
VP8LDelete(VP8LDecoder * const dec)1401 void VP8LDelete(VP8LDecoder* const dec) {
1402 if (dec != NULL) {
1403 VP8LClear(dec);
1404 WebPSafeFree(dec);
1405 }
1406 }
1407
UpdateDecoder(VP8LDecoder * const dec,int width,int height)1408 static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) {
1409 VP8LMetadata* const hdr = &dec->hdr_;
1410 const int num_bits = hdr->huffman_subsample_bits_;
1411 dec->width_ = width;
1412 dec->height_ = height;
1413
1414 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits);
1415 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1;
1416 }
1417
DecodeImageStream(int xsize,int ysize,int is_level0,VP8LDecoder * const dec,uint32_t ** const decoded_data)1418 static int DecodeImageStream(int xsize, int ysize,
1419 int is_level0,
1420 VP8LDecoder* const dec,
1421 uint32_t** const decoded_data) {
1422 int ok = 1;
1423 int transform_xsize = xsize;
1424 int transform_ysize = ysize;
1425 VP8LBitReader* const br = &dec->br_;
1426 VP8LMetadata* const hdr = &dec->hdr_;
1427 uint32_t* data = NULL;
1428 int color_cache_bits = 0;
1429
1430 // Read the transforms (may recurse).
1431 if (is_level0) {
1432 while (ok && VP8LReadBits(br, 1)) {
1433 ok = ReadTransform(&transform_xsize, &transform_ysize, dec);
1434 }
1435 }
1436
1437 // Color cache
1438 if (ok && VP8LReadBits(br, 1)) {
1439 color_cache_bits = VP8LReadBits(br, 4);
1440 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS);
1441 if (!ok) {
1442 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1443 goto End;
1444 }
1445 }
1446
1447 // Read the Huffman codes (may recurse).
1448 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize,
1449 color_cache_bits, is_level0);
1450 if (!ok) {
1451 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1452 goto End;
1453 }
1454
1455 // Finish setting up the color-cache
1456 if (color_cache_bits > 0) {
1457 hdr->color_cache_size_ = 1 << color_cache_bits;
1458 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) {
1459 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1460 ok = 0;
1461 goto End;
1462 }
1463 } else {
1464 hdr->color_cache_size_ = 0;
1465 }
1466 UpdateDecoder(dec, transform_xsize, transform_ysize);
1467
1468 if (is_level0) { // level 0 complete
1469 dec->state_ = READ_HDR;
1470 goto End;
1471 }
1472
1473 {
1474 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize;
1475 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data));
1476 if (data == NULL) {
1477 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1478 ok = 0;
1479 goto End;
1480 }
1481 }
1482
1483 // Use the Huffman trees to decode the LZ77 encoded data.
1484 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize,
1485 transform_ysize, NULL);
1486 ok = ok && !br->eos_;
1487
1488 End:
1489 if (!ok) {
1490 WebPSafeFree(data);
1491 ClearMetadata(hdr);
1492 } else {
1493 if (decoded_data != NULL) {
1494 *decoded_data = data;
1495 } else {
1496 // We allocate image data in this function only for transforms. At level 0
1497 // (that is: not the transforms), we shouldn't have allocated anything.
1498 assert(data == NULL);
1499 assert(is_level0);
1500 }
1501 dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls.
1502 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind.
1503 }
1504 return ok;
1505 }
1506
1507 //------------------------------------------------------------------------------
1508 // Allocate internal buffers dec->pixels_ and dec->argb_cache_.
AllocateInternalBuffers32b(VP8LDecoder * const dec,int final_width)1509 static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) {
1510 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_;
1511 // Scratch buffer corresponding to top-prediction row for transforming the
1512 // first row in the row-blocks. Not needed for paletted alpha.
1513 const uint64_t cache_top_pixels = (uint16_t)final_width;
1514 // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
1515 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS;
1516 const uint64_t total_num_pixels =
1517 num_pixels + cache_top_pixels + cache_pixels;
1518
1519 assert(dec->width_ <= final_width);
1520 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t));
1521 if (dec->pixels_ == NULL) {
1522 dec->argb_cache_ = NULL; // for soundness
1523 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1524 return 0;
1525 }
1526 dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels;
1527 return 1;
1528 }
1529
AllocateInternalBuffers8b(VP8LDecoder * const dec)1530 static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
1531 const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_;
1532 dec->argb_cache_ = NULL; // for soundness
1533 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t));
1534 if (dec->pixels_ == NULL) {
1535 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1536 return 0;
1537 }
1538 return 1;
1539 }
1540
1541 //------------------------------------------------------------------------------
1542
1543 // Special row-processing that only stores the alpha data.
ExtractAlphaRows(VP8LDecoder * const dec,int last_row)1544 static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) {
1545 int cur_row = dec->last_row_;
1546 int num_rows = last_row - cur_row;
1547 const uint32_t* in = dec->pixels_ + dec->width_ * cur_row;
1548
1549 assert(last_row <= dec->io_->crop_bottom);
1550 while (num_rows > 0) {
1551 const int num_rows_to_process =
1552 (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows;
1553 // Extract alpha (which is stored in the green plane).
1554 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
1555 uint8_t* const output = alph_dec->output_;
1556 const int width = dec->io_->width; // the final width (!= dec->width_)
1557 const int cache_pixs = width * num_rows_to_process;
1558 uint8_t* const dst = output + width * cur_row;
1559 const uint32_t* const src = dec->argb_cache_;
1560 ApplyInverseTransforms(dec, cur_row, num_rows_to_process, in);
1561 WebPExtractGreen(src, dst, cache_pixs);
1562 AlphaApplyFilter(alph_dec,
1563 cur_row, cur_row + num_rows_to_process, dst, width);
1564 num_rows -= num_rows_to_process;
1565 in += num_rows_to_process * dec->width_;
1566 cur_row += num_rows_to_process;
1567 }
1568 assert(cur_row == last_row);
1569 dec->last_row_ = dec->last_out_row_ = last_row;
1570 }
1571
VP8LDecodeAlphaHeader(ALPHDecoder * const alph_dec,const uint8_t * const data,size_t data_size)1572 int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
1573 const uint8_t* const data, size_t data_size) {
1574 int ok = 0;
1575 VP8LDecoder* dec = VP8LNew();
1576
1577 if (dec == NULL) return 0;
1578
1579 assert(alph_dec != NULL);
1580
1581 dec->width_ = alph_dec->width_;
1582 dec->height_ = alph_dec->height_;
1583 dec->io_ = &alph_dec->io_;
1584 dec->io_->opaque = alph_dec;
1585 dec->io_->width = alph_dec->width_;
1586 dec->io_->height = alph_dec->height_;
1587
1588 dec->status_ = VP8_STATUS_OK;
1589 VP8LInitBitReader(&dec->br_, data, data_size);
1590
1591 if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) {
1592 goto Err;
1593 }
1594
1595 // Special case: if alpha data uses only the color indexing transform and
1596 // doesn't use color cache (a frequent case), we will use DecodeAlphaData()
1597 // method that only needs allocation of 1 byte per pixel (alpha channel).
1598 if (dec->next_transform_ == 1 &&
1599 dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM &&
1600 Is8bOptimizable(&dec->hdr_)) {
1601 alph_dec->use_8b_decode_ = 1;
1602 ok = AllocateInternalBuffers8b(dec);
1603 } else {
1604 // Allocate internal buffers (note that dec->width_ may have changed here).
1605 alph_dec->use_8b_decode_ = 0;
1606 ok = AllocateInternalBuffers32b(dec, alph_dec->width_);
1607 }
1608
1609 if (!ok) goto Err;
1610
1611 // Only set here, once we are sure it is valid (to avoid thread races).
1612 alph_dec->vp8l_dec_ = dec;
1613 return 1;
1614
1615 Err:
1616 VP8LDelete(dec);
1617 return 0;
1618 }
1619
VP8LDecodeAlphaImageStream(ALPHDecoder * const alph_dec,int last_row)1620 int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) {
1621 VP8LDecoder* const dec = alph_dec->vp8l_dec_;
1622 assert(dec != NULL);
1623 assert(last_row <= dec->height_);
1624
1625 if (dec->last_row_ >= last_row) {
1626 return 1; // done
1627 }
1628
1629 if (!alph_dec->use_8b_decode_) WebPInitAlphaProcessing();
1630
1631 // Decode (with special row processing).
1632 return alph_dec->use_8b_decode_ ?
1633 DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
1634 last_row) :
1635 DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1636 last_row, ExtractAlphaRows);
1637 }
1638
1639 //------------------------------------------------------------------------------
1640
VP8LDecodeHeader(VP8LDecoder * const dec,VP8Io * const io)1641 int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) {
1642 int width, height, has_alpha;
1643
1644 if (dec == NULL) return 0;
1645 if (io == NULL) {
1646 dec->status_ = VP8_STATUS_INVALID_PARAM;
1647 return 0;
1648 }
1649
1650 dec->io_ = io;
1651 dec->status_ = VP8_STATUS_OK;
1652 VP8LInitBitReader(&dec->br_, io->data, io->data_size);
1653 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) {
1654 dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
1655 goto Error;
1656 }
1657 dec->state_ = READ_DIM;
1658 io->width = width;
1659 io->height = height;
1660
1661 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error;
1662 return 1;
1663
1664 Error:
1665 VP8LClear(dec);
1666 assert(dec->status_ != VP8_STATUS_OK);
1667 return 0;
1668 }
1669
VP8LDecodeImage(VP8LDecoder * const dec)1670 int VP8LDecodeImage(VP8LDecoder* const dec) {
1671 VP8Io* io = NULL;
1672 WebPDecParams* params = NULL;
1673
1674 if (dec == NULL) return 0;
1675
1676 assert(dec->hdr_.huffman_tables_ != NULL);
1677 assert(dec->hdr_.htree_groups_ != NULL);
1678 assert(dec->hdr_.num_htree_groups_ > 0);
1679
1680 io = dec->io_;
1681 assert(io != NULL);
1682 params = (WebPDecParams*)io->opaque;
1683 assert(params != NULL);
1684
1685 // Initialization.
1686 if (dec->state_ != READ_DATA) {
1687 dec->output_ = params->output;
1688 assert(dec->output_ != NULL);
1689
1690 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
1691 dec->status_ = VP8_STATUS_INVALID_PARAM;
1692 goto Err;
1693 }
1694
1695 if (!AllocateInternalBuffers32b(dec, io->width)) goto Err;
1696
1697 #if !defined(WEBP_REDUCE_SIZE)
1698 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
1699 #else
1700 if (io->use_scaling) {
1701 dec->status_ = VP8_STATUS_INVALID_PARAM;
1702 goto Err;
1703 }
1704 #endif
1705 if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) {
1706 // need the alpha-multiply functions for premultiplied output or rescaling
1707 WebPInitAlphaProcessing();
1708 }
1709
1710 if (!WebPIsRGBMode(dec->output_->colorspace)) {
1711 WebPInitConvertARGBToYUV();
1712 if (dec->output_->u.YUVA.a != NULL) WebPInitAlphaProcessing();
1713 }
1714 if (dec->incremental_) {
1715 if (dec->hdr_.color_cache_size_ > 0 &&
1716 dec->hdr_.saved_color_cache_.colors_ == NULL) {
1717 if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_,
1718 dec->hdr_.color_cache_.hash_bits_)) {
1719 dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
1720 goto Err;
1721 }
1722 }
1723 }
1724 dec->state_ = READ_DATA;
1725 }
1726
1727 // Decode.
1728 if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
1729 io->crop_bottom, ProcessRows)) {
1730 goto Err;
1731 }
1732
1733 params->last_y = dec->last_out_row_;
1734 return 1;
1735
1736 Err:
1737 VP8LClear(dec);
1738 assert(dec->status_ != VP8_STATUS_OK);
1739 return 0;
1740 }
1741
1742 //------------------------------------------------------------------------------
1743