src/libFLAC/metadata_object.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2001,2002  Josh Coalson
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA  02111-1307, USA.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 #include "private/metadata.h"
  24
  25 #include "FLAC/assert.h"
  26
  27
  28 /****************************************************************************
  29  *
  30  * Local routines
  31  *
  32  ***************************************************************************/
  33
  34 static FLAC__bool copy_bytes_(FLAC__byte **to, const FLAC__byte *from, unsigned bytes)
  35 {
  36         if(bytes > 0 && 0 != from) {
  37                 FLAC__byte *x;
  38                 if(0 == (x = malloc(bytes)))
  39                         return false;
  40                 memcpy(x, from, bytes);
  41                 *to = x;
  42         }
  43         else {
  44                 FLAC__ASSERT(0 == from);
  45                 FLAC__ASSERT(bytes == 0);
  46                 *to = 0;
  47         }
  48         return true;
  49 }
  50
  51 static FLAC__bool copy_vcentry_(FLAC__StreamMetadata_VorbisComment_Entry *to, const FLAC__StreamMetadata_VorbisComment_Entry *from)
  52 {
  53         to->length = from->length;
  54         if(0 == from->entry) {
  55                 FLAC__ASSERT(from->length == 0);
  56                 to->entry = 0;
  57         }
  58         else {
  59                 FLAC__byte *x;
  60                 FLAC__ASSERT(from->length > 0);
  61                 if(0 == (x = malloc(from->length)))
  62                         return false;
  63                 memcpy(x, from->entry, from->length);
  64                 to->entry = x;
  65         }
  66         return true;
  67 }
  68
  69 static void seektable_calculate_length_(FLAC__StreamMetadata *object)
  70 {
  71         FLAC__ASSERT(0 != object);
  72         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
  73
  74         object->length = object->data.seek_table.num_points * FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
  75 }
  76
  77 static FLAC__StreamMetadata_SeekPoint *seekpoint_array_new_(unsigned num_points)
  78 {
  79         FLAC__StreamMetadata_SeekPoint *object_array;
  80
  81         FLAC__ASSERT(num_points > 0);
  82
  83         object_array = malloc(num_points * sizeof(FLAC__StreamMetadata_SeekPoint));
  84
  85         if(0 != object_array) {
  86                 unsigned i;
  87                 for(i = 0; i < num_points; i++) {
  88                         object_array[i].sample_number = FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER;
  89                         object_array[i].stream_offset = 0;
  90                         object_array[i].frame_samples = 0;
  91                 }
  92         }
  93
  94         return object_array;
  95 }
  96
  97 static void vorbiscomment_calculate_length_(FLAC__StreamMetadata *object)
  98 {
  99         unsigned i;
 100
 101         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 102
 103         object->length = (FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN) / 8;
 104         object->length += object->data.vorbis_comment.vendor_string.length;
 105         object->length += (FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8;
 106         for(i = 0; i < object->data.vorbis_comment.num_comments; i++) {
 107                 object->length += (FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8);
 108                 object->length += object->data.vorbis_comment.comments[i].length;
 109         }
 110 }
 111
 112 static FLAC__StreamMetadata_VorbisComment_Entry *vorbiscomment_entry_array_new_(unsigned num_comments)
 113 {
 114         FLAC__StreamMetadata_VorbisComment_Entry *object_array;
 115
 116         FLAC__ASSERT(num_comments > 0);
 117
 118         object_array = malloc(num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry));
 119
 120         if(0 != object_array)
 121                 memset(object_array, 0, num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry));
 122
 123         return object_array;
 124 }
 125
 126 static void vorbiscomment_entry_array_delete_(FLAC__StreamMetadata_VorbisComment_Entry *object_array, unsigned num_comments)
 127 {
 128         unsigned i;
 129
 130         FLAC__ASSERT(0 != object_array && num_comments > 0);
 131
 132         for(i = 0; i < num_comments; i++)
 133                 if(0 != object_array[i].entry)
 134                         free(object_array[i].entry);
 135
 136         if(0 != object_array)
 137                 free(object_array);
 138 }
 139
 140 static FLAC__StreamMetadata_VorbisComment_Entry *vorbiscomment_entry_array_copy_(const FLAC__StreamMetadata_VorbisComment_Entry *object_array, unsigned num_comments)
 141 {
 142         FLAC__StreamMetadata_VorbisComment_Entry *return_array;
 143
 144         FLAC__ASSERT(0 != object_array);
 145         FLAC__ASSERT(num_comments > 0);
 146
 147         return_array = vorbiscomment_entry_array_new_(num_comments);
 148
 149         if(0 != return_array) {
 150                 unsigned i;
 151
 152                 /* Need to do this to set the pointers inside the comments to 0.
 153                  * In case of an error in the following loop, the object will be
 154                  * deleted and we don't want the destructor freeing uninitialized
 155                  * pointers.
 156                  */
 157                 memset(return_array, 0, num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry));
 158
 159                 for(i = 0; i < num_comments; i++) {
 160                         if(!copy_vcentry_(return_array+i, object_array+i)) {
 161                                 vorbiscomment_entry_array_delete_(return_array, num_comments);
 162                                 return 0;
 163                         }
 164                 }
 165         }
 166
 167         return return_array;
 168 }
 169
 170 static FLAC__bool vorbiscomment_set_entry_(FLAC__StreamMetadata *object, FLAC__StreamMetadata_VorbisComment_Entry *dest, const FLAC__StreamMetadata_VorbisComment_Entry *src, FLAC__bool copy)
 171 {
 172         FLAC__byte *save;
 173
 174         FLAC__ASSERT(0 != object);
 175         FLAC__ASSERT(0 != dest);
 176         FLAC__ASSERT(0 != src);
 177         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 178         FLAC__ASSERT((0 != src->entry && src->length > 0) || (0 == src->entry && src->length == 0 && copy == false));
 179
 180         save = dest->entry;
 181
 182         /* do the copy first so that if we fail we leave the object untouched */
 183         if(copy) {
 184                 if(!copy_vcentry_(dest, src))
 185                         return false;
 186         }
 187         else {
 188                 *dest = *src;
 189         }
 190
 191         if(0 != save)
 192                 free(save);
 193
 194         vorbiscomment_calculate_length_(object);
 195         return true;
 196 }
 197
 198
 199 /****************************************************************************
 200  *
 201  * Metadata object routines
 202  *
 203  ***************************************************************************/
 204
 205 /*@@@move
 206 will return pointer to new empty object of type 'type', or 0 if malloc failed
 207 type is valid type
 208 */
 209 FLAC__StreamMetadata *FLAC__metadata_object_new(FLAC__MetadataType type)
 210 {
 211         FLAC__StreamMetadata *object = malloc(sizeof(FLAC__StreamMetadata));
 212         if(0 != object) {
 213                 memset(object, 0, sizeof(FLAC__StreamMetadata));
 214                 object->is_last = false;
 215                 object->type = type;
 216                 switch(type) {
 217                         case FLAC__METADATA_TYPE_STREAMINFO:
 218                                 object->length = FLAC__STREAM_METADATA_STREAMINFO_LENGTH;
 219                                 break;
 220                         case FLAC__METADATA_TYPE_PADDING:
 221                                 break;
 222                         case FLAC__METADATA_TYPE_APPLICATION:
 223                                 object->length = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
 224                                 break;
 225                         case FLAC__METADATA_TYPE_SEEKTABLE:
 226                                 break;
 227                         case FLAC__METADATA_TYPE_VORBIS_COMMENT:
 228                                 object->length = (FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN + FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8;
 229                                 break;
 230                         default:
 231                                 /* double protection: */
 232                                 FLAC__ASSERT(0);
 233                                 free(object);
 234                                 return 0;
 235                 }
 236         }
 237
 238         return object;
 239 }
 240
 241 /*@@@move
 242 return a pointer to a copy of 'object', or 0 if any malloc failed.  does a deep copy.  user gets ownership of object.
 243     FLAC__ASSERT(0 != object);
 244 */
 245 FLAC__StreamMetadata *FLAC__metadata_object_clone(const FLAC__StreamMetadata *object)
 246 {
 247         FLAC__StreamMetadata *to;
 248
 249         FLAC__ASSERT(0 != object);
 250
 251         if(0 != (to = FLAC__metadata_object_new(object->type))) {
 252                 to->is_last = object->is_last;
 253                 to->type = object->type;
 254                 to->length = object->length;
 255                 switch(to->type) {
 256                         case FLAC__METADATA_TYPE_STREAMINFO:
 257                                 memcpy(&to->data.stream_info, &object->data.stream_info, sizeof(FLAC__StreamMetadata_StreamInfo));
 258                                 break;
 259                         case FLAC__METADATA_TYPE_PADDING:
 260                                 break;
 261                         case FLAC__METADATA_TYPE_APPLICATION:
 262                                 memcpy(&to->data.application.id, &object->data.application.id, FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8);
 263                                 if(!copy_bytes_(&to->data.application.data, object->data.application.data, object->length - FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8)) {
 264                                         FLAC__metadata_object_delete(to);
 265                                         return 0;
 266                                 }
 267                                 break;
 268                         case FLAC__METADATA_TYPE_SEEKTABLE:
 269                                 to->data.seek_table.num_points = object->data.seek_table.num_points;
 270                                 if(!copy_bytes_((FLAC__byte**)&to->data.seek_table.points, (FLAC__byte*)object->data.seek_table.points, object->data.seek_table.num_points * sizeof(FLAC__StreamMetadata_SeekPoint))) {
 271                                         FLAC__metadata_object_delete(to);
 272                                         return 0;
 273                                 }
 274                                 break;
 275                         case FLAC__METADATA_TYPE_VORBIS_COMMENT:
 276                                 if(!copy_vcentry_(&to->data.vorbis_comment.vendor_string, &object->data.vorbis_comment.vendor_string)) {
 277                                         FLAC__metadata_object_delete(to);
 278                                         return 0;
 279                                 }
 280                                 if(object->data.vorbis_comment.num_comments == 0) {
 281                                         FLAC__ASSERT(0 == object->data.vorbis_comment.comments);
 282                                         to->data.vorbis_comment.comments = 0;
 283                                 }
 284                                 else {
 285                                         FLAC__ASSERT(0 != object->data.vorbis_comment.comments);
 286                                         to->data.vorbis_comment.comments = vorbiscomment_entry_array_copy_(object->data.vorbis_comment.comments, object->data.vorbis_comment.num_comments);
 287                                         if(0 == to->data.vorbis_comment.comments) {
 288                                                 FLAC__metadata_object_delete(to);
 289                                                 return 0;
 290                                         }
 291                                 }
 292                                 to->data.vorbis_comment.num_comments = object->data.vorbis_comment.num_comments;
 293                                 break;
 294                         default:
 295                                 /* double protection: */
 296                                 FLAC__ASSERT(0);
 297                                 free(to);
 298                                 return 0;
 299                 }
 300         }
 301
 302         return to;
 303 }
 304
 305 void FLAC__metadata_object_delete_data(FLAC__StreamMetadata *object)
 306 {
 307         FLAC__ASSERT(0 != object);
 308
 309         switch(object->type) {
 310                 case FLAC__METADATA_TYPE_STREAMINFO:
 311                 case FLAC__METADATA_TYPE_PADDING:
 312                         break;
 313                 case FLAC__METADATA_TYPE_APPLICATION:
 314                         if(0 != object->data.application.data)
 315                                 free(object->data.application.data);
 316                         break;
 317                 case FLAC__METADATA_TYPE_SEEKTABLE:
 318                         if(0 != object->data.seek_table.points)
 319                                 free(object->data.seek_table.points);
 320                         break;
 321                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
 322                         if(0 != object->data.vorbis_comment.vendor_string.entry)
 323                                 free(object->data.vorbis_comment.vendor_string.entry);
 324                         if(0 != object->data.vorbis_comment.comments) {
 325                                 FLAC__ASSERT(object->data.vorbis_comment.num_comments > 0);
 326                                 vorbiscomment_entry_array_delete_(object->data.vorbis_comment.comments, object->data.vorbis_comment.num_comments);
 327                         }
 328                         break;
 329                 default:
 330                         FLAC__ASSERT(0);
 331         }
 332 }
 333
 334 /*@@@move
 335 frees 'object'.  does a deep delete.
 336 */
 337 void FLAC__metadata_object_delete(FLAC__StreamMetadata *object)
 338 {
 339         FLAC__metadata_object_delete_data(object);
 340         free(object);
 341 }
 342
 343 static FLAC__bool compare_block_data_streaminfo_(const FLAC__StreamMetadata_StreamInfo *block1, const FLAC__StreamMetadata_StreamInfo *block2)
 344 {
 345         if(block1->min_blocksize != block2->min_blocksize)
 346                 return false;
 347         if(block1->max_blocksize != block2->max_blocksize)
 348                 return false;
 349         if(block1->min_framesize != block2->min_framesize)
 350                 return false;
 351         if(block1->max_framesize != block2->max_framesize)
 352                 return false;
 353         if(block1->sample_rate != block2->sample_rate)
 354                 return false;
 355         if(block1->channels != block2->channels)
 356                 return false;
 357         if(block1->bits_per_sample != block2->bits_per_sample)
 358                 return false;
 359         if(block1->total_samples != block2->total_samples)
 360                 return false;
 361         if(0 != memcmp(block1->md5sum, block2->md5sum, 16))
 362                 return false;
 363         return true;
 364 }
 365
 366 static FLAC__bool compare_block_data_application_(const FLAC__StreamMetadata_Application *block1, const FLAC__StreamMetadata_Application *block2, unsigned block_length)
 367 {
 368         FLAC__ASSERT(0 != block1);
 369         FLAC__ASSERT(0 != block2);
 370         FLAC__ASSERT(block_length >= sizeof(block1->id));
 371
 372         if(0 != memcmp(block1->id, block2->id, sizeof(block1->id)))
 373                 return false;
 374         if(0 != block1->data && 0 != block2->data)
 375                 return 0 == memcmp(block1->data, block2->data, block_length - sizeof(block1->id));
 376         else
 377                 return block1->data == block2->data;
 378 }
 379
 380 static FLAC__bool compare_block_data_seektable_(const FLAC__StreamMetadata_SeekTable *block1, const FLAC__StreamMetadata_SeekTable *block2)
 381 {
 382         unsigned i;
 383
 384         FLAC__ASSERT(0 != block1);
 385         FLAC__ASSERT(0 != block2);
 386
 387         if(block1->num_points != block2->num_points)
 388                 return false;
 389
 390         if(0 != block1->points && 0 != block2->points) {
 391                 for(i = 0; i < block1->num_points; i++) {
 392                         if(block1->points[i].sample_number != block2->points[i].sample_number)
 393                                 return false;
 394                         if(block1->points[i].stream_offset != block2->points[i].stream_offset)
 395                                 return false;
 396                         if(block1->points[i].frame_samples != block2->points[i].frame_samples)
 397                                 return false;
 398                 }
 399                 return true;
 400         }
 401         else
 402                 return block1->points == block2->points;
 403 }
 404
 405 static FLAC__bool compare_block_data_vorbiscomment_(const FLAC__StreamMetadata_VorbisComment *block1, const FLAC__StreamMetadata_VorbisComment *block2)
 406 {
 407         unsigned i;
 408
 409         if(block1->vendor_string.length != block2->vendor_string.length)
 410                 return false;
 411
 412         if(0 != block1->vendor_string.entry && 0 != block2->vendor_string.entry) {
 413                 if(0 != memcmp(block1->vendor_string.entry, block2->vendor_string.entry, block1->vendor_string.length))
 414                         return false;
 415         }
 416         else if(block1->vendor_string.entry != block2->vendor_string.entry)
 417                 return false;
 418
 419         if(block1->num_comments != block2->num_comments)
 420                 return false;
 421
 422         for(i = 0; i < block1->num_comments; i++) {
 423                 if(0 != block1->comments[i].entry && 0 != block2->comments[i].entry) {
 424                         if(0 != memcmp(block1->comments[i].entry, block2->comments[i].entry, block1->comments[i].length))
 425                                 return false;
 426                 }
 427                 else if(block1->comments[i].entry != block2->comments[i].entry)
 428                         return false;
 429         }
 430         return true;
 431 }
 432
 433 FLAC__bool FLAC__metadata_object_is_equal(const FLAC__StreamMetadata *block1, const FLAC__StreamMetadata *block2)
 434 {
 435         if(block1->type != block2->type) {
 436                 return false;
 437     }
 438         if(block1->is_last != block2->is_last) {
 439                 return false;
 440     }
 441         if(block1->length != block2->length) {
 442                 return false;
 443     }
 444         switch(block1->type) {
 445                 case FLAC__METADATA_TYPE_STREAMINFO:
 446                         return compare_block_data_streaminfo_(&block1->data.stream_info, &block2->data.stream_info);
 447                 case FLAC__METADATA_TYPE_PADDING:
 448                         return true; /* we don't compare the padding guts */
 449                 case FLAC__METADATA_TYPE_APPLICATION:
 450                         return compare_block_data_application_(&block1->data.application, &block2->data.application, block1->length);
 451                 case FLAC__METADATA_TYPE_SEEKTABLE:
 452                         return compare_block_data_seektable_(&block1->data.seek_table, &block2->data.seek_table);
 453                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
 454                         return compare_block_data_vorbiscomment_(&block1->data.vorbis_comment, &block2->data.vorbis_comment);
 455                 default:
 456                         FLAC__ASSERT(0);
 457                         return false;
 458         }
 459 }
 460
 461 /*@@@move
 462 sets the application data to 'data'.  if 'copy' is true, makes, copy, else takes ownership of pointer.  returns false if copy==true and malloc fails.
 463     FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_APPLICATION);
 464     FLAC__ASSERT((0 != data && length > 0) || (0 == data && length == 0 && copy == false));
 465 */
 466 FLAC__bool FLAC__metadata_object_application_set_data(FLAC__StreamMetadata *object, FLAC__byte *data, unsigned length, FLAC__bool copy)
 467 {
 468         FLAC__byte *save;
 469
 470         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_APPLICATION);
 471         FLAC__ASSERT((0 != data && length > 0) || (0 == data && length == 0 && copy == false));
 472
 473         save = object->data.application.data;
 474
 475         /* do the copy first so that if we fail we leave the object untouched */
 476         if(copy) {
 477                 if(!copy_bytes_(&object->data.application.data, data, length))
 478                         return false;
 479         }
 480         else {
 481                 object->data.application.data = data;
 482         }
 483
 484         if(0 != save)
 485                 free(save);
 486
 487         object->length = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8 + length;
 488         return true;
 489 }
 490
 491 FLAC__bool FLAC__metadata_object_seektable_resize_points(FLAC__StreamMetadata *object, unsigned new_num_points)
 492 {
 493         FLAC__ASSERT(0 != object);
 494         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
 495
 496         if(0 == object->data.seek_table.points) {
 497                 FLAC__ASSERT(object->data.seek_table.num_points == 0);
 498                 if(0 == new_num_points)
 499                         return true;
 500                 else if(0 == (object->data.seek_table.points = seekpoint_array_new_(new_num_points)))
 501                         return false;
 502         }
 503         else {
 504                 const unsigned old_size = object->data.seek_table.num_points * sizeof(FLAC__StreamMetadata_SeekPoint);
 505                 const unsigned new_size = new_num_points * sizeof(FLAC__StreamMetadata_SeekPoint);
 506
 507                 FLAC__ASSERT(object->data.seek_table.num_points > 0);
 508
 509                 if(new_size == 0) {
 510                         free(object->data.seek_table.points);
 511                         object->data.seek_table.points = 0;
 512                 }
 513                 else if(0 == (object->data.seek_table.points = realloc(object->data.seek_table.points, new_size)))
 514                         return false;
 515
 516                 /* if growing, set new elements to placeholders */
 517                 if(new_size > old_size) {
 518                         unsigned i;
 519                         for(i = object->data.seek_table.num_points; i < new_num_points; i++) {
 520                                 object->data.seek_table.points[i].sample_number = FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER;
 521                                 object->data.seek_table.points[i].stream_offset = 0;
 522                                 object->data.seek_table.points[i].frame_samples = 0;
 523                         }
 524                 }
 525         }
 526
 527         object->data.seek_table.num_points = new_num_points;
 528
 529         seektable_calculate_length_(object);
 530         return true;
 531 }
 532
 533 void FLAC__metadata_object_seektable_set_point(FLAC__StreamMetadata *object, unsigned point_num, FLAC__StreamMetadata_SeekPoint point)
 534 {
 535         FLAC__ASSERT(0 != object);
 536         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
 537         FLAC__ASSERT(object->data.seek_table.num_points > point_num);
 538
 539         object->data.seek_table.points[point_num] = point;
 540 }
 541
 542 FLAC__bool FLAC__metadata_object_seektable_insert_point(FLAC__StreamMetadata *object, unsigned point_num, FLAC__StreamMetadata_SeekPoint point)
 543 {
 544         int i;
 545
 546         FLAC__ASSERT(0 != object);
 547         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
 548         FLAC__ASSERT(object->data.seek_table.num_points >= point_num);
 549
 550         if(!FLAC__metadata_object_seektable_resize_points(object, object->data.seek_table.num_points+1))
 551                 return false;
 552
 553         /* move all points >= point_num forward one space */
 554         for(i = (int)object->data.seek_table.num_points-1; i > (int)point_num; i--)
 555                 object->data.seek_table.points[i] = object->data.seek_table.points[i-1];
 556
 557         FLAC__metadata_object_seektable_set_point(object, point_num, point);
 558         seektable_calculate_length_(object);
 559         return true;
 560 }
 561
 562 FLAC__bool FLAC__metadata_object_seektable_delete_point(FLAC__StreamMetadata *object, unsigned point_num)
 563 {
 564         unsigned i;
 565
 566         FLAC__ASSERT(0 != object);
 567         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
 568         FLAC__ASSERT(object->data.seek_table.num_points > point_num);
 569
 570         /* move all points > point_num backward one space */
 571         for(i = point_num; i < object->data.seek_table.num_points-1; i++)
 572                 object->data.seek_table.points[i] = object->data.seek_table.points[i+1];
 573
 574         return FLAC__metadata_object_seektable_resize_points(object, object->data.seek_table.num_points-1);
 575 }
 576
 577 FLAC__bool FLAC__metadata_object_seektable_is_legal(const FLAC__StreamMetadata *object)
 578 {
 579         unsigned i;
 580         FLAC__uint64 prev_sample_number = 0;
 581         FLAC__bool got_prev = false;
 582
 583         FLAC__ASSERT(0 != object);
 584         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_SEEKTABLE);
 585
 586         {
 587                 const FLAC__StreamMetadata_SeekTable *seek_table = &object->data.seek_table;
 588
 589                 for(i = 0; i < seek_table->num_points; i++) {
 590                         if(got_prev) {
 591                                 if(seek_table->points[i].sample_number <= prev_sample_number)
 592                                         return false;
 593                         }
 594                         prev_sample_number = seek_table->points[i].sample_number;
 595                         got_prev = true;
 596                 }
 597         }
 598
 599         return true;
 600 }
 601
 602 FLAC__bool FLAC__metadata_object_vorbiscomment_set_vendor_string(FLAC__StreamMetadata *object, FLAC__StreamMetadata_VorbisComment_Entry entry, FLAC__bool copy)
 603 {
 604         return vorbiscomment_set_entry_(object, &object->data.vorbis_comment.vendor_string, &entry, copy);
 605 }
 606
 607 FLAC__bool FLAC__metadata_object_vorbiscomment_resize_comments(FLAC__StreamMetadata *object, unsigned new_num_comments)
 608 {
 609         FLAC__ASSERT(0 != object);
 610         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 611
 612         if(0 == object->data.vorbis_comment.comments) {
 613                 FLAC__ASSERT(object->data.vorbis_comment.num_comments == 0);
 614                 if(0 == new_num_comments)
 615                         return true;
 616                 else if(0 == (object->data.vorbis_comment.comments = vorbiscomment_entry_array_new_(new_num_comments)))
 617                         return false;
 618         }
 619         else {
 620                 const unsigned old_size = object->data.vorbis_comment.num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry);
 621                 const unsigned new_size = new_num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry);
 622
 623                 FLAC__ASSERT(object->data.vorbis_comment.num_comments > 0);
 624
 625                 /* if shrinking, free the truncated entries */
 626                 if(new_num_comments < object->data.vorbis_comment.num_comments) {
 627                         unsigned i;
 628                         for(i = new_num_comments; i < object->data.vorbis_comment.num_comments; i++)
 629                                 if(0 != object->data.vorbis_comment.comments[i].entry)
 630                                         free(object->data.vorbis_comment.comments[i].entry);
 631                 }
 632
 633                 if(new_size == 0) {
 634                         free(object->data.vorbis_comment.comments);
 635                         object->data.vorbis_comment.comments = 0;
 636                 }
 637                 else if(0 == (object->data.vorbis_comment.comments = realloc(object->data.vorbis_comment.comments, new_size)))
 638                         return false;
 639
 640                 /* if growing, zero all the length/pointers of new elements */
 641                 if(new_size > old_size)
 642                         memset(object->data.vorbis_comment.comments + object->data.vorbis_comment.num_comments, 0, new_size - old_size);
 643         }
 644
 645         object->data.vorbis_comment.num_comments = new_num_comments;
 646
 647         vorbiscomment_calculate_length_(object);
 648         return true;
 649 }
 650
 651 FLAC__bool FLAC__metadata_object_vorbiscomment_set_comment(FLAC__StreamMetadata *object, unsigned comment_num, FLAC__StreamMetadata_VorbisComment_Entry entry, FLAC__bool copy)
 652 {
 653         return vorbiscomment_set_entry_(object, &object->data.vorbis_comment.comments[comment_num], &entry, copy);
 654 }
 655
 656 FLAC__bool FLAC__metadata_object_vorbiscomment_insert_comment(FLAC__StreamMetadata *object, unsigned comment_num, FLAC__StreamMetadata_VorbisComment_Entry entry, FLAC__bool copy)
 657 {
 658         FLAC__StreamMetadata_VorbisComment *vc;
 659
 660         FLAC__ASSERT(0 != object);
 661         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 662         FLAC__ASSERT(object->data.vorbis_comment.num_comments >= comment_num);
 663
 664         vc = &object->data.vorbis_comment;
 665
 666         if(!FLAC__metadata_object_vorbiscomment_resize_comments(object, vc->num_comments+1))
 667                 return false;
 668
 669         /* move all comments >= comment_num forward one space */
 670         memmove(&vc->comments[comment_num+1], &vc->comments[comment_num], sizeof(FLAC__StreamMetadata_VorbisComment_Entry)*(vc->num_comments-1-comment_num));
 671         vc->comments[comment_num].length = 0;
 672         vc->comments[comment_num].entry = 0;
 673
 674         return FLAC__metadata_object_vorbiscomment_set_comment(object, comment_num, entry, copy);
 675 }
 676
 677 FLAC__bool FLAC__metadata_object_vorbiscomment_delete_comment(FLAC__StreamMetadata *object, unsigned comment_num)
 678 {
 679         FLAC__StreamMetadata_VorbisComment *vc;
 680
 681         FLAC__ASSERT(0 != object);
 682         FLAC__ASSERT(object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 683         FLAC__ASSERT(object->data.vorbis_comment.num_comments > comment_num);
 684
 685         vc = &object->data.vorbis_comment;
 686
 687         /* free the comment at comment_num */
 688         if(0 != vc->comments[comment_num].entry)
 689                 free(vc->comments[comment_num].entry);
 690
 691         /* move all comments > comment_num backward one space */
 692         memmove(&vc->comments[comment_num], &vc->comments[comment_num+1], sizeof(FLAC__StreamMetadata_VorbisComment_Entry)*(vc->num_comments-comment_num-1));
 693         vc->comments[vc->num_comments-1].length = 0;
 694         vc->comments[vc->num_comments-1].entry = 0;
 695
 696         return FLAC__metadata_object_vorbiscomment_resize_comments(object, vc->num_comments-1);
 697 }