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