summaryrefslogtreecommitdiff
path: root/drivers/webpold/mux/muxinternal.c
blob: 6c3c4fe60ae410839d1c658ecaa389b7f1a4961e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
// Copyright 2011 Google Inc. All Rights Reserved.
//
// This code is licensed under the same terms as WebM:
//  Software License Agreement:  http://www.webmproject.org/license/software/
//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Internal objects and utils for mux.
//
// Authors: Urvang (urvang@google.com)
//          Vikas (vikasa@google.com)

#include <assert.h>
#include "./muxi.h"

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#define UNDEFINED_CHUNK_SIZE (-1)

const ChunkInfo kChunks[] = {
  { MKFOURCC('V', 'P', '8', 'X'),  WEBP_CHUNK_VP8X,    VP8X_CHUNK_SIZE },
  { MKFOURCC('I', 'C', 'C', 'P'),  WEBP_CHUNK_ICCP,    UNDEFINED_CHUNK_SIZE },
  { MKFOURCC('L', 'O', 'O', 'P'),  WEBP_CHUNK_LOOP,    LOOP_CHUNK_SIZE },
  { MKFOURCC('F', 'R', 'M', ' '),  WEBP_CHUNK_FRAME,   FRAME_CHUNK_SIZE },
  { MKFOURCC('T', 'I', 'L', 'E'),  WEBP_CHUNK_TILE,    TILE_CHUNK_SIZE },
  { MKFOURCC('A', 'L', 'P', 'H'),  WEBP_CHUNK_ALPHA,   UNDEFINED_CHUNK_SIZE },
  { MKFOURCC('V', 'P', '8', ' '),  WEBP_CHUNK_IMAGE,   UNDEFINED_CHUNK_SIZE },
  { MKFOURCC('V', 'P', '8', 'L'),  WEBP_CHUNK_IMAGE,   UNDEFINED_CHUNK_SIZE },
  { MKFOURCC('M', 'E', 'T', 'A'),  WEBP_CHUNK_META,    UNDEFINED_CHUNK_SIZE },
  { MKFOURCC('U', 'N', 'K', 'N'),  WEBP_CHUNK_UNKNOWN, UNDEFINED_CHUNK_SIZE },

  { NIL_TAG,                    WEBP_CHUNK_NIL,     UNDEFINED_CHUNK_SIZE }
};

//------------------------------------------------------------------------------
// Life of a chunk object.

void ChunkInit(WebPChunk* const chunk) {
  assert(chunk);
  memset(chunk, 0, sizeof(*chunk));
  chunk->tag_ = NIL_TAG;
}

WebPChunk* ChunkRelease(WebPChunk* const chunk) {
  WebPChunk* next;
  if (chunk == NULL) return NULL;
  if (chunk->owner_) {
    WebPDataClear(&chunk->data_);
  }
  next = chunk->next_;
  ChunkInit(chunk);
  return next;
}

//------------------------------------------------------------------------------
// Chunk misc methods.

CHUNK_INDEX ChunkGetIndexFromTag(uint32_t tag) {
  int i;
  for (i = 0; kChunks[i].tag != NIL_TAG; ++i) {
    if (tag == kChunks[i].tag) return i;
  }
  return IDX_NIL;
}

WebPChunkId ChunkGetIdFromTag(uint32_t tag) {
  int i;
  for (i = 0; kChunks[i].tag != NIL_TAG; ++i) {
    if (tag == kChunks[i].tag) return kChunks[i].id;
  }
  return WEBP_CHUNK_NIL;
}

//------------------------------------------------------------------------------
// Chunk search methods.

// Returns next chunk in the chunk list with the given tag.
static WebPChunk* ChunkSearchNextInList(WebPChunk* chunk, uint32_t tag) {
  while (chunk && chunk->tag_ != tag) {
    chunk = chunk->next_;
  }
  return chunk;
}

WebPChunk* ChunkSearchList(WebPChunk* first, uint32_t nth, uint32_t tag) {
  uint32_t iter = nth;
  first = ChunkSearchNextInList(first, tag);
  if (!first) return NULL;

  while (--iter != 0) {
    WebPChunk* next_chunk = ChunkSearchNextInList(first->next_, tag);
    if (next_chunk == NULL) break;
    first = next_chunk;
  }
  return ((nth > 0) && (iter > 0)) ? NULL : first;
}

// Outputs a pointer to 'prev_chunk->next_',
//   where 'prev_chunk' is the pointer to the chunk at position (nth - 1).
// Returns 1 if nth chunk was found, 0 otherwise.
static int ChunkSearchListToSet(WebPChunk** chunk_list, uint32_t nth,
                                WebPChunk*** const location) {
  uint32_t count = 0;
  assert(chunk_list);
  *location = chunk_list;

  while (*chunk_list) {
    WebPChunk* const cur_chunk = *chunk_list;
    ++count;
    if (count == nth) return 1;  // Found.
    chunk_list = &cur_chunk->next_;
    *location = chunk_list;
  }

  // *chunk_list is ok to be NULL if adding at last location.
  return (nth == 0 || (count == nth - 1)) ? 1 : 0;
}

//------------------------------------------------------------------------------
// Chunk writer methods.

WebPMuxError ChunkAssignData(WebPChunk* chunk, const WebPData* const data,
                             int copy_data, uint32_t tag) {
  // For internally allocated chunks, always copy data & make it owner of data.
  if (tag == kChunks[IDX_VP8X].tag || tag == kChunks[IDX_LOOP].tag) {
    copy_data = 1;
  }

  ChunkRelease(chunk);

  if (data != NULL) {
    if (copy_data) {
      // Copy data.
      chunk->data_.bytes_ = (uint8_t*)malloc(data->size_);
      if (chunk->data_.bytes_ == NULL) return WEBP_MUX_MEMORY_ERROR;
      memcpy((uint8_t*)chunk->data_.bytes_, data->bytes_, data->size_);
      chunk->data_.size_ = data->size_;

      // Chunk is owner of data.
      chunk->owner_ = 1;
    } else {
      // Don't copy data.
      chunk->data_ = *data;
    }
  }

  chunk->tag_ = tag;

  return WEBP_MUX_OK;
}

WebPMuxError ChunkSetNth(const WebPChunk* chunk, WebPChunk** chunk_list,
                         uint32_t nth) {
  WebPChunk* new_chunk;

  if (!ChunkSearchListToSet(chunk_list, nth, &chunk_list)) {
    return WEBP_MUX_NOT_FOUND;
  }

  new_chunk = (WebPChunk*)malloc(sizeof(*new_chunk));
  if (new_chunk == NULL) return WEBP_MUX_MEMORY_ERROR;
  *new_chunk = *chunk;
  new_chunk->next_ = *chunk_list;
  *chunk_list = new_chunk;
  return WEBP_MUX_OK;
}

//------------------------------------------------------------------------------
// Chunk deletion method(s).

WebPChunk* ChunkDelete(WebPChunk* const chunk) {
  WebPChunk* const next = ChunkRelease(chunk);
  free(chunk);
  return next;
}

//------------------------------------------------------------------------------
// Chunk serialization methods.

size_t ChunksListDiskSize(const WebPChunk* chunk_list) {
  size_t size = 0;
  while (chunk_list) {
    size += ChunkDiskSize(chunk_list);
    chunk_list = chunk_list->next_;
  }
  return size;
}

static uint8_t* ChunkEmit(const WebPChunk* const chunk, uint8_t* dst) {
  const size_t chunk_size = chunk->data_.size_;
  assert(chunk);
  assert(chunk->tag_ != NIL_TAG);
  PutLE32(dst + 0, chunk->tag_);
  PutLE32(dst + TAG_SIZE, (uint32_t)chunk_size);
  assert(chunk_size == (uint32_t)chunk_size);
  memcpy(dst + CHUNK_HEADER_SIZE, chunk->data_.bytes_, chunk_size);
  if (chunk_size & 1)
    dst[CHUNK_HEADER_SIZE + chunk_size] = 0;  // Add padding.
  return dst + ChunkDiskSize(chunk);
}

uint8_t* ChunkListEmit(const WebPChunk* chunk_list, uint8_t* dst) {
  while (chunk_list) {
    dst = ChunkEmit(chunk_list, dst);
    chunk_list = chunk_list->next_;
  }
  return dst;
}

//------------------------------------------------------------------------------
// Manipulation of a WebPData object.

void WebPDataInit(WebPData* webp_data) {
  if (webp_data != NULL) {
    memset(webp_data, 0, sizeof(*webp_data));
  }
}

void WebPDataClear(WebPData* webp_data) {
  if (webp_data != NULL) {
    free((void*)webp_data->bytes_);
    WebPDataInit(webp_data);
  }
}

int WebPDataCopy(const WebPData* src, WebPData* dst) {
  if (src == NULL || dst == NULL) return 0;

  WebPDataInit(dst);
  if (src->bytes_ != NULL && src->size_ != 0) {
    dst->bytes_ = (uint8_t*)malloc(src->size_);
    if (dst->bytes_ == NULL) return 0;
    memcpy((void*)dst->bytes_, src->bytes_, src->size_);
    dst->size_ = src->size_;
  }
  return 1;
}

//------------------------------------------------------------------------------
// Life of a MuxImage object.

void MuxImageInit(WebPMuxImage* const wpi) {
  assert(wpi);
  memset(wpi, 0, sizeof(*wpi));
}

WebPMuxImage* MuxImageRelease(WebPMuxImage* const wpi) {
  WebPMuxImage* next;
  if (wpi == NULL) return NULL;
  ChunkDelete(wpi->header_);
  ChunkDelete(wpi->alpha_);
  ChunkDelete(wpi->img_);

  next = wpi->next_;
  MuxImageInit(wpi);
  return next;
}

//------------------------------------------------------------------------------
// MuxImage search methods.

int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id) {
  int count = 0;
  const WebPMuxImage* current;
  for (current = wpi_list; current != NULL; current = current->next_) {
    const WebPChunk* const wpi_chunk = *MuxImageGetListFromId(current, id);
    if (wpi_chunk != NULL) {
      const WebPChunkId wpi_chunk_id = ChunkGetIdFromTag(wpi_chunk->tag_);
      if (wpi_chunk_id == id) ++count;
    }
  }
  return count;
}

// Outputs a pointer to 'prev_wpi->next_',
//   where 'prev_wpi' is the pointer to the image at position (nth - 1).
// Returns 1 if nth image with given id was found, 0 otherwise.
static int SearchImageToGetOrDelete(WebPMuxImage** wpi_list, uint32_t nth,
                                    WebPChunkId id,
                                    WebPMuxImage*** const location) {
  uint32_t count = 0;
  assert(wpi_list);
  *location = wpi_list;

  // Search makes sense only for the following.
  assert(id == WEBP_CHUNK_FRAME || id == WEBP_CHUNK_TILE ||
         id == WEBP_CHUNK_IMAGE);
  assert(id != WEBP_CHUNK_IMAGE || nth == 1);

  if (nth == 0) {
    nth = MuxImageCount(*wpi_list, id);
    if (nth == 0) return 0;  // Not found.
  }

  while (*wpi_list) {
    WebPMuxImage* const cur_wpi = *wpi_list;
    const WebPChunk* const wpi_chunk = *MuxImageGetListFromId(cur_wpi, id);
    if (wpi_chunk != NULL) {
      const WebPChunkId wpi_chunk_id = ChunkGetIdFromTag(wpi_chunk->tag_);
      if (wpi_chunk_id == id) {
        ++count;
        if (count == nth) return 1;  // Found.
      }
    }
    wpi_list = &cur_wpi->next_;
    *location = wpi_list;
  }
  return 0;  // Not found.
}

//------------------------------------------------------------------------------
// MuxImage writer methods.

WebPMuxError MuxImagePush(const WebPMuxImage* wpi, WebPMuxImage** wpi_list) {
  WebPMuxImage* new_wpi;

  while (*wpi_list != NULL) {
    WebPMuxImage* const cur_wpi = *wpi_list;
    if (cur_wpi->next_ == NULL) break;
    wpi_list = &cur_wpi->next_;
  }

  new_wpi = (WebPMuxImage*)malloc(sizeof(*new_wpi));
  if (new_wpi == NULL) return WEBP_MUX_MEMORY_ERROR;
  *new_wpi = *wpi;
  new_wpi->next_ = NULL;

  if (*wpi_list != NULL) {
    (*wpi_list)->next_ = new_wpi;
  } else {
    *wpi_list = new_wpi;
  }
  return WEBP_MUX_OK;
}

//------------------------------------------------------------------------------
// MuxImage deletion methods.

WebPMuxImage* MuxImageDelete(WebPMuxImage* const wpi) {
  // Delete the components of wpi. If wpi is NULL this is a noop.
  WebPMuxImage* const next = MuxImageRelease(wpi);
  free(wpi);
  return next;
}

void MuxImageDeleteAll(WebPMuxImage** const wpi_list) {
  while (*wpi_list) {
    *wpi_list = MuxImageDelete(*wpi_list);
  }
}

WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth,
                               WebPChunkId id) {
  assert(wpi_list);
  if (!SearchImageToGetOrDelete(wpi_list, nth, id, &wpi_list)) {
    return WEBP_MUX_NOT_FOUND;
  }
  *wpi_list = MuxImageDelete(*wpi_list);
  return WEBP_MUX_OK;
}

//------------------------------------------------------------------------------
// MuxImage reader methods.

WebPMuxError MuxImageGetNth(const WebPMuxImage** wpi_list, uint32_t nth,
                            WebPChunkId id, WebPMuxImage** wpi) {
  assert(wpi_list);
  assert(wpi);
  if (!SearchImageToGetOrDelete((WebPMuxImage**)wpi_list, nth, id,
                                (WebPMuxImage***)&wpi_list)) {
    return WEBP_MUX_NOT_FOUND;
  }
  *wpi = (WebPMuxImage*)*wpi_list;
  return WEBP_MUX_OK;
}

//------------------------------------------------------------------------------
// MuxImage serialization methods.

// Size of an image.
size_t MuxImageDiskSize(const WebPMuxImage* const wpi) {
  size_t size = 0;
  if (wpi->header_ != NULL) size += ChunkDiskSize(wpi->header_);
  if (wpi->alpha_ != NULL) size += ChunkDiskSize(wpi->alpha_);
  if (wpi->img_ != NULL) size += ChunkDiskSize(wpi->img_);
  return size;
}

size_t MuxImageListDiskSize(const WebPMuxImage* wpi_list) {
  size_t size = 0;
  while (wpi_list) {
    size += MuxImageDiskSize(wpi_list);
    wpi_list = wpi_list->next_;
  }
  return size;
}

uint8_t* MuxImageEmit(const WebPMuxImage* const wpi, uint8_t* dst) {
  // Ordering of chunks to be emitted is strictly as follows:
  // 1. Frame/Tile chunk (if present).
  // 2. Alpha chunk (if present).
  // 3. VP8/VP8L chunk.
  assert(wpi);
  if (wpi->header_ != NULL) dst = ChunkEmit(wpi->header_, dst);
  if (wpi->alpha_ != NULL) dst = ChunkEmit(wpi->alpha_, dst);
  if (wpi->img_ != NULL) dst = ChunkEmit(wpi->img_, dst);
  return dst;
}

uint8_t* MuxImageListEmit(const WebPMuxImage* wpi_list, uint8_t* dst) {
  while (wpi_list) {
    dst = MuxImageEmit(wpi_list, dst);
    wpi_list = wpi_list->next_;
  }
  return dst;
}

//------------------------------------------------------------------------------
// Helper methods for mux.

int MuxHasLosslessImages(const WebPMuxImage* images) {
  while (images != NULL) {
    assert(images->img_ != NULL);
    if (images->img_->tag_ == kChunks[IDX_VP8L].tag) {
      return 1;
    }
    images = images->next_;
  }
  return 0;
}

uint8_t* MuxEmitRiffHeader(uint8_t* const data, size_t size) {
  PutLE32(data + 0, MKFOURCC('R', 'I', 'F', 'F'));
  PutLE32(data + TAG_SIZE, (uint32_t)size - CHUNK_HEADER_SIZE);
  assert(size == (uint32_t)size);
  PutLE32(data + TAG_SIZE + CHUNK_SIZE_BYTES, MKFOURCC('W', 'E', 'B', 'P'));
  return data + RIFF_HEADER_SIZE;
}

WebPChunk** MuxGetChunkListFromId(const WebPMux* mux, WebPChunkId id) {
  assert(mux != NULL);
  switch(id) {
    case WEBP_CHUNK_VP8X:    return (WebPChunk**)&mux->vp8x_;
    case WEBP_CHUNK_ICCP:    return (WebPChunk**)&mux->iccp_;
    case WEBP_CHUNK_LOOP:    return (WebPChunk**)&mux->loop_;
    case WEBP_CHUNK_META:    return (WebPChunk**)&mux->meta_;
    case WEBP_CHUNK_UNKNOWN: return (WebPChunk**)&mux->unknown_;
    default: return NULL;
  }
}

WebPMuxError MuxValidateForImage(const WebPMux* const mux) {
  const int num_images = MuxImageCount(mux->images_, WEBP_CHUNK_IMAGE);
  const int num_frames = MuxImageCount(mux->images_, WEBP_CHUNK_FRAME);
  const int num_tiles  = MuxImageCount(mux->images_, WEBP_CHUNK_TILE);

  if (num_images == 0) {
    // No images in mux.
    return WEBP_MUX_NOT_FOUND;
  } else if (num_images == 1 && num_frames == 0 && num_tiles == 0) {
    // Valid case (single image).
    return WEBP_MUX_OK;
  } else {
    // Frame/Tile case OR an invalid mux.
    return WEBP_MUX_INVALID_ARGUMENT;
  }
}

static int IsNotCompatible(int feature, int num_items) {
  return (feature != 0) != (num_items > 0);
}

#define NO_FLAG 0

// Test basic constraints:
// retrieval, maximum number of chunks by index (use -1 to skip)
// and feature incompatibility (use NO_FLAG to skip).
// On success returns WEBP_MUX_OK and stores the chunk count in *num.
static WebPMuxError ValidateChunk(const WebPMux* const mux, CHUNK_INDEX idx,
                                  WebPFeatureFlags feature,
                                  WebPFeatureFlags vp8x_flags,
                                  int max, int* num) {
  const WebPMuxError err =
      WebPMuxNumChunks(mux, kChunks[idx].id, num);
  if (err != WEBP_MUX_OK) return err;
  if (max > -1 && *num > max) return WEBP_MUX_INVALID_ARGUMENT;
  if (feature != NO_FLAG && IsNotCompatible(vp8x_flags & feature, *num)) {
    return WEBP_MUX_INVALID_ARGUMENT;
  }
  return WEBP_MUX_OK;
}

WebPMuxError MuxValidate(const WebPMux* const mux) {
  int num_iccp;
  int num_meta;
  int num_loop_chunks;
  int num_frames;
  int num_tiles;
  int num_vp8x;
  int num_images;
  int num_alpha;
  uint32_t flags;
  WebPMuxError err;

  // Verify mux is not NULL.
  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;

  // Verify mux has at least one image.
  if (mux->images_ == NULL) return WEBP_MUX_INVALID_ARGUMENT;

  err = WebPMuxGetFeatures(mux, &flags);
  if (err != WEBP_MUX_OK) return err;

  // At most one color profile chunk.
  err = ValidateChunk(mux, IDX_ICCP, ICCP_FLAG, flags, 1, &num_iccp);
  if (err != WEBP_MUX_OK) return err;

  // At most one XMP metadata.
  err = ValidateChunk(mux, IDX_META, META_FLAG, flags, 1, &num_meta);
  if (err != WEBP_MUX_OK) return err;

  // Animation: ANIMATION_FLAG, loop chunk and frame chunk(s) are consistent.
  // At most one loop chunk.
  err = ValidateChunk(mux, IDX_LOOP, NO_FLAG, flags, 1, &num_loop_chunks);
  if (err != WEBP_MUX_OK) return err;
  err = ValidateChunk(mux, IDX_FRAME, NO_FLAG, flags, -1, &num_frames);
  if (err != WEBP_MUX_OK) return err;

  {
    const int has_animation = !!(flags & ANIMATION_FLAG);
    if (has_animation && (num_loop_chunks == 0 || num_frames == 0)) {
      return WEBP_MUX_INVALID_ARGUMENT;
    }
    if (!has_animation && (num_loop_chunks == 1 || num_frames > 0)) {
      return WEBP_MUX_INVALID_ARGUMENT;
    }
  }

  // Tiling: TILE_FLAG and tile chunk(s) are consistent.
  err = ValidateChunk(mux, IDX_TILE, TILE_FLAG, flags, -1, &num_tiles);
  if (err != WEBP_MUX_OK) return err;

  // Verify either VP8X chunk is present OR there is only one elem in
  // mux->images_.
  err = ValidateChunk(mux, IDX_VP8X, NO_FLAG, flags, 1, &num_vp8x);
  if (err != WEBP_MUX_OK) return err;
  err = ValidateChunk(mux, IDX_VP8, NO_FLAG, flags, -1, &num_images);
  if (err != WEBP_MUX_OK) return err;
  if (num_vp8x == 0 && num_images != 1) return WEBP_MUX_INVALID_ARGUMENT;

  // ALPHA_FLAG & alpha chunk(s) are consistent.
  if (num_vp8x > 0 && MuxHasLosslessImages(mux->images_)) {
    // Special case: we have a VP8X chunk as well as some lossless images.
    if (!(flags & ALPHA_FLAG)) return WEBP_MUX_INVALID_ARGUMENT;
  } else {
    err = ValidateChunk(mux, IDX_ALPHA, ALPHA_FLAG, flags, -1, &num_alpha);
    if (err != WEBP_MUX_OK) return err;
  }

  // num_tiles & num_images are consistent.
  if (num_tiles > 0 && num_images != num_tiles) {
    return WEBP_MUX_INVALID_ARGUMENT;
  }

  return WEBP_MUX_OK;
}

#undef NO_FLAG

//------------------------------------------------------------------------------

#if defined(__cplusplus) || defined(c_plusplus)
}    // extern "C"
#endif