src/libFLAC/metadata_iterators.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 #if !defined _MSC_VER && !defined __MINGW32__
  21 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
  22 #include <errno.h>
  23 #endif
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #if defined _MSC_VER || defined __MINGW32__
  29 #include <sys/utime.h> /* for utime() */
  30 #include <io.h> /* for chmod() */
  31 #else
  32 #include <sys/types.h> /* some flavors of BSD (like OS X) require this to get time_t */
  33 #include <utime.h> /* for utime() */
  34 #include <unistd.h> /* for chown(), unlink() */
  35 #endif
  36 #include <sys/stat.h> /* for stat(), maybe chmod() */
  37
  38 #include "private/metadata.h"
  39
  40 #include "FLAC/assert.h"
  41 #include "FLAC/file_decoder.h"
  42
  43 #ifdef max
  44 #undef max
  45 #endif
  46 #define max(a,b) ((a)>(b)?(a):(b))
  47 #ifdef min
  48 #undef min
  49 #endif
  50 #define min(a,b) ((a)<(b)?(a):(b))
  51
  52
  53 /****************************************************************************
  54  *
  55  * Local function declarations
  56  *
  57  ***************************************************************************/
  58
  59 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  60 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  61 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
  62 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
  63 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
  64 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
  65
  66 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
  67 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
  68 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_(FILE *file, FLAC__StreamMetadata_StreamInfo *block);
  69 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_(FILE *file, FLAC__StreamMetadata_Padding *block, unsigned block_length);
  70 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_(FILE *file, FLAC__StreamMetadata_Application *block, unsigned block_length);
  71 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_(FILE *file, FLAC__StreamMetadata_SeekTable *block, unsigned block_length);
  72 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_(FILE *file, FLAC__StreamMetadata_VorbisComment_Entry *entry);
  73 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_(FILE *file, FLAC__StreamMetadata_VorbisComment *block);
  74
  75 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  76 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  77 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_streaminfo_(FILE *file, const FLAC__StreamMetadata_StreamInfo *block);
  78 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_padding_(FILE *file, const FLAC__StreamMetadata_Padding *block, unsigned block_length);
  79 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_application_(FILE *file, const FLAC__StreamMetadata_Application *block, unsigned block_length);
  80 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_seektable_(FILE *file, const FLAC__StreamMetadata_SeekTable *block);
  81 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_vorbis_comment_(FILE *file, const FLAC__StreamMetadata_VorbisComment *block);
  82 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
  83 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
  84 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
  85
  86 static FLAC__bool chain_rewrite_chain_(FLAC__Metadata_Chain *chain);
  87 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix);
  88
  89 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
  90 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
  91
  92 /* return 0 if OK, 1 if read error, 2 if not a FLAC file */
  93 static unsigned seek_to_first_metadata_block_(FILE *f);
  94
  95 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
  96 static FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, long fixup_is_last_flag_offset, FLAC__bool backup);
  97
  98 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status);
  99 static FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status);
 100
 101 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 102 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 103 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
 104
 105 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats);
 106 static void set_file_stats_(const char *filename, struct stat *stats);
 107
 108 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
 109
 110
 111 /****************************************************************************
 112  *
 113  * Level 0 implementation
 114  *
 115  ***************************************************************************/
 116
 117 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
 118 static void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
 119 static void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
 120
 121 typedef struct {
 122         FLAC__bool got_error;
 123         FLAC__bool got_streaminfo;
 124         FLAC__StreamMetadata *streaminfo;
 125 } level0_client_data;
 126
 127 FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 128 {
 129         level0_client_data cd;
 130         FLAC__FileDecoder *decoder;
 131
 132         FLAC__ASSERT(0 != filename);
 133         FLAC__ASSERT(0 != streaminfo);
 134
 135         decoder = FLAC__file_decoder_new();
 136
 137         if(0 == decoder)
 138                 return false;
 139
 140         cd.got_error = false;
 141         cd.got_streaminfo = false;
 142         cd.streaminfo = streaminfo;
 143
 144         FLAC__file_decoder_set_md5_checking(decoder, false);
 145         FLAC__file_decoder_set_filename(decoder, filename);
 146         FLAC__file_decoder_set_write_callback(decoder, write_callback_);
 147         FLAC__file_decoder_set_metadata_callback(decoder, metadata_callback_);
 148         FLAC__file_decoder_set_error_callback(decoder, error_callback_);
 149         FLAC__file_decoder_set_client_data(decoder, &cd);
 150
 151         if(FLAC__file_decoder_init(decoder) != FLAC__FILE_DECODER_OK || cd.got_error) {
 152                 FLAC__file_decoder_finish(decoder);
 153                 FLAC__file_decoder_delete(decoder);
 154                 return false;
 155         }
 156
 157         /* the first thing decoded must be the STREAMINFO block: */
 158         if(!FLAC__file_decoder_process_single(decoder) || cd.got_error) {
 159                 FLAC__file_decoder_finish(decoder);
 160                 FLAC__file_decoder_delete(decoder);
 161                 return false;
 162         }
 163
 164         FLAC__file_decoder_finish(decoder);
 165         FLAC__file_decoder_delete(decoder);
 166
 167         return !cd.got_error && cd.got_streaminfo;
 168 }
 169
 170 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 171 {
 172         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 173
 174         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 175 }
 176
 177 void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 178 {
 179         level0_client_data *cd = (level0_client_data *)client_data;
 180         (void)decoder;
 181
 182         if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO && 0 != cd->streaminfo) {
 183                 *(cd->streaminfo) = *metadata;
 184                 cd->got_streaminfo = true;
 185         }
 186 }
 187
 188 void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 189 {
 190         level0_client_data *cd = (level0_client_data *)client_data;
 191         (void)decoder;
 192
 193         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 194                 cd->got_error = true;
 195 }
 196
 197
 198 /****************************************************************************
 199  *
 200  * Level 1 implementation
 201  *
 202  ***************************************************************************/
 203
 204 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 205 /* 1 for initial offset, +4 for our own personal use */
 206
 207 struct FLAC__Metadata_SimpleIterator {
 208         FILE *file;
 209         char *filename, *tempfile_path_prefix;
 210         struct stat stats;
 211         FLAC__bool has_stats;
 212         FLAC__bool is_writable;
 213         FLAC__Metadata_SimpleIteratorStatus status;
 214         /*@@@ 2G limits here because of the offset type: */
 215         long offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 216         long first_offset; /* this is the offset to the STREAMINFO block */
 217         unsigned depth;
 218         /* this is the metadata block header of the current block we are pointing to: */
 219         FLAC__bool is_last;
 220         FLAC__MetadataType type;
 221         unsigned length;
 222 };
 223
 224 const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 225         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 226         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 227         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 228         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 229         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 230         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 231         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 232         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 233         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 234         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 235         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 236         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 237         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 238 };
 239
 240
 241 FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 242 {
 243         FLAC__Metadata_SimpleIterator *iterator = malloc(sizeof(FLAC__Metadata_SimpleIterator));
 244
 245         if(0 != iterator) {
 246                 iterator->file = 0;
 247                 iterator->filename = 0;
 248                 iterator->tempfile_path_prefix = 0;
 249                 iterator->has_stats = false;
 250                 iterator->is_writable = false;
 251                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 252                 iterator->first_offset = iterator->offset[0] = -1;
 253                 iterator->depth = 0;
 254         }
 255
 256         return iterator;
 257 }
 258
 259 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 260 {
 261         FLAC__ASSERT(0 != iterator);
 262
 263         if(0 != iterator->file) {
 264                 fclose(iterator->file);
 265                 iterator->file = 0;
 266                 if(iterator->has_stats)
 267                         set_file_stats_(iterator->filename, &iterator->stats);
 268         }
 269         if(0 != iterator->filename) {
 270                 free(iterator->filename);
 271                 iterator->filename = 0;
 272         }
 273         if(0 != iterator->tempfile_path_prefix) {
 274                 free(iterator->tempfile_path_prefix);
 275                 iterator->tempfile_path_prefix = 0;
 276         }
 277 }
 278
 279 void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 280 {
 281         FLAC__ASSERT(0 != iterator);
 282
 283         simple_iterator_free_guts_(iterator);
 284         free(iterator);
 285 }
 286
 287 FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 288 {
 289         FLAC__Metadata_SimpleIteratorStatus status;
 290
 291         FLAC__ASSERT(0 != iterator);
 292
 293         status = iterator->status;
 294         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 295         return status;
 296 }
 297
 298 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator)
 299 {
 300         unsigned ret;
 301
 302         FLAC__ASSERT(0 != iterator);
 303
 304         iterator->is_writable = false;
 305
 306         if(0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 307 #if !defined _MSC_VER && !defined __MINGW32__
 308 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
 309                 if(errno == EACCES) {
 310 #endif
 311                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 312                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 313                                 return false;
 314                         }
 315 #if !defined _MSC_VER && !defined __MINGW32__
 316                 }
 317                 else {
 318                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 319                         return false;
 320                 }
 321 #endif
 322         }
 323         else {
 324                 iterator->is_writable = true;
 325         }
 326
 327         ret = seek_to_first_metadata_block_(iterator->file);
 328         switch(ret) {
 329                 case 0:
 330                         iterator->depth = 0;
 331                         iterator->first_offset = iterator->offset[iterator->depth] = ftell(iterator->file);
 332                         return read_metadata_block_header_(iterator);
 333                 case 1:
 334                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 335                         return false;
 336                 case 2:
 337                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 338                         return false;
 339                 default:
 340                         FLAC__ASSERT(0);
 341                         return false;
 342         }
 343 }
 344
 345 #if 0
 346 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 347 /*
 348  * The 'tempfile_path_prefix' allows you to specify a directory where
 349  * tempfiles should go.  Remember that if your metadata edits cause the
 350  * FLAC file to grow, the entire file will have to be rewritten.  If
 351  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 352  * same directory as the original FLAC file.  This makes replacing the
 353  * original with the tempfile fast but requires extra space in the same
 354  * partition for the tempfile.  If space is a problem, you can pass a
 355  * directory name belonging to a different partition in
 356  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 357  * '/' as the directory separator.  A trailing slash is not needed; it
 358  * will be added automatically.
 359  */
 360 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 361 #endif
 362
 363 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats)
 364 {
 365         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 366
 367         FLAC__ASSERT(0 != iterator);
 368         FLAC__ASSERT(0 != filename);
 369
 370         simple_iterator_free_guts_(iterator);
 371
 372         if(preserve_file_stats)
 373                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 374
 375         if(0 == (iterator->filename = strdup(filename))) {
 376                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 377                 return false;
 378         }
 379         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 380                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 381                 return false;
 382         }
 383
 384         return simple_iterator_prime_input_(iterator);
 385 }
 386
 387 FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 388 {
 389         FLAC__ASSERT(0 != iterator);
 390         FLAC__ASSERT(0 != iterator->file);
 391
 392         return iterator->is_writable;
 393 }
 394
 395 FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 396 {
 397         FLAC__ASSERT(0 != iterator);
 398         FLAC__ASSERT(0 != iterator->file);
 399
 400         if(iterator->is_last)
 401                 return false;
 402
 403         if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 404                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 405                 return false;
 406         }
 407
 408         iterator->offset[iterator->depth] = ftell(iterator->file);
 409
 410         return read_metadata_block_header_(iterator);
 411 }
 412
 413 FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 414 {
 415         long this_offset;
 416
 417         FLAC__ASSERT(0 != iterator);
 418         FLAC__ASSERT(0 != iterator->file);
 419
 420         if(iterator->offset[iterator->depth] == iterator->first_offset)
 421                 return false;
 422
 423         if(0 != fseek(iterator->file, iterator->first_offset, SEEK_SET)) {
 424                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 425                 return false;
 426         }
 427         this_offset = iterator->first_offset;
 428         if(!read_metadata_block_header_(iterator))
 429                 return false;
 430
 431         /* we ignore any error from ftell() and catch it in fseek() */
 432         while(ftell(iterator->file) + (long)iterator->length < iterator->offset[iterator->depth]) {
 433                 if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 434                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 435                         return false;
 436                 }
 437                 this_offset = ftell(iterator->file);
 438                 if(!read_metadata_block_header_(iterator))
 439                         return false;
 440         }
 441
 442         iterator->offset[iterator->depth] = this_offset;
 443
 444         return true;
 445 }
 446
 447 FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 448 {
 449         FLAC__ASSERT(0 != iterator);
 450         FLAC__ASSERT(0 != iterator->file);
 451
 452         return iterator->type;
 453 }
 454
 455 FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 456 {
 457         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 458
 459         FLAC__ASSERT(0 != iterator);
 460         FLAC__ASSERT(0 != iterator->file);
 461
 462         if(0 != block) {
 463                 block->is_last = iterator->is_last;
 464                 block->length = iterator->length;
 465
 466                 if(!read_metadata_block_data_(iterator, block)) {
 467                         FLAC__metadata_object_delete(block);
 468                         return 0;
 469                 }
 470
 471                 /* back up to the beginning of the block data to stay consistent */
 472                 if(0 != fseek(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 473                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 474                         FLAC__metadata_object_delete(block);
 475                         return 0;
 476                 }
 477         }
 478         else
 479                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 480
 481         return block;
 482 }
 483
 484 FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 485 {
 486         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 487         FLAC__bool ret;
 488
 489         FLAC__ASSERT(0 != iterator);
 490         FLAC__ASSERT(0 != iterator->file);
 491         FLAC__ASSERT(0 != block);
 492
 493         if(!iterator->is_writable) {
 494                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 495                 return false;
 496         }
 497
 498         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 499                 if(iterator->type != block->type) {
 500                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 501                         return false;
 502                 }
 503         }
 504
 505         block->is_last = iterator->is_last;
 506
 507         if(iterator->length == block->length)
 508                 return write_metadata_block_stationary_(iterator, block);
 509         else if(iterator->length > block->length) {
 510                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 511                         ret =  write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 512                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 513                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 514                         return ret;
 515                 }
 516                 else {
 517                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 518                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 519                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 520                         return ret;
 521                 }
 522         }
 523         else /* iterator->length < block->length */ {
 524                 unsigned padding_leftover = 0;
 525                 FLAC__bool padding_is_last = false;
 526                 if(use_padding) {
 527                         /* first see if we can even use padding */
 528                         if(iterator->is_last) {
 529                                 use_padding = false;
 530                         }
 531                         else {
 532                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 533                                 simple_iterator_push_(iterator);
 534                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 535                                         (void)simple_iterator_pop_(iterator);
 536                                         return false;
 537                                 }
 538                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 539                                         use_padding = false;
 540                                 }
 541                                 else {
 542                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 543                                                 padding_leftover = 0;
 544                                                 block->is_last = iterator->is_last;
 545                                         }
 546                                         else if(iterator->length < extra_padding_bytes_required)
 547                                                 use_padding = false;
 548                                         else {
 549                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 550                                                 padding_is_last = iterator->is_last;
 551                                                 block->is_last = false;
 552                                         }
 553                                 }
 554                                 if(!simple_iterator_pop_(iterator))
 555                                         return false;
 556                         }
 557                 }
 558                 if(use_padding) {
 559                         if(padding_leftover == 0) {
 560                                 ret = write_metadata_block_stationary_(iterator, block);
 561                                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 562                                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 563                                 return ret;
 564                         }
 565                         else {
 566                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 567                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 568                                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 569                                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 570                                 return ret;
 571                         }
 572                 }
 573                 else {
 574                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 575                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 576                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 577                         return ret;
 578                 }
 579         }
 580 }
 581
 582 FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 583 {
 584         unsigned padding_leftover = 0;
 585         FLAC__bool padding_is_last = false;
 586
 587         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 588         FLAC__bool ret;
 589
 590         FLAC__ASSERT(0 != iterator);
 591         FLAC__ASSERT(0 != iterator->file);
 592         FLAC__ASSERT(0 != block);
 593
 594         if(!iterator->is_writable)
 595                 return false;
 596
 597         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 598                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 599                 return false;
 600         }
 601
 602         block->is_last = iterator->is_last;
 603
 604         if(use_padding) {
 605                 /* first see if we can even use padding */
 606                 if(iterator->is_last) {
 607                         use_padding = false;
 608                 }
 609                 else {
 610                         simple_iterator_push_(iterator);
 611                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 612                                 (void)simple_iterator_pop_(iterator);
 613                                 return false;
 614                         }
 615                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 616                                 use_padding = false;
 617                         }
 618                         else {
 619                                 if(iterator->length == block->length) {
 620                                         padding_leftover = 0;
 621                                         block->is_last = iterator->is_last;
 622                                 }
 623                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 624                                         use_padding = false;
 625                                 else {
 626                                         padding_leftover = iterator->length - block->length;
 627                                         padding_is_last = iterator->is_last;
 628                                         block->is_last = false;
 629                                 }
 630                         }
 631                         if(!simple_iterator_pop_(iterator))
 632                                 return false;
 633                 }
 634         }
 635         if(use_padding) {
 636                 /* move to the next block, which is suitable padding */
 637                 if(!FLAC__metadata_simple_iterator_next(iterator))
 638                         return false;
 639                 if(padding_leftover == 0) {
 640                         ret = write_metadata_block_stationary_(iterator, block);
 641                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 642                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 643                         return ret;
 644                 }
 645                 else {
 646                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 647                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 648                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 649                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 650                         return ret;
 651                 }
 652         }
 653         else {
 654                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 655                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 656                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 657                 return ret;
 658         }
 659 }
 660
 661 FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 662 {
 663         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 664         FLAC__bool ret;
 665
 666         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 667                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 668                 return false;
 669         }
 670
 671         if(use_padding) {
 672                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 673                 if(0 == padding) {
 674                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 675                         return false;
 676                 }
 677                 padding->length = iterator->length;
 678                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 679                         FLAC__metadata_object_delete(padding);
 680                         return false;
 681                 }
 682                 FLAC__metadata_object_delete(padding);
 683                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 684                         return false;
 685                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 686                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 687                 return true;
 688         }
 689         else {
 690                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 691                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 692                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 693                 return ret;
 694         }
 695 }
 696
 697
 698
 699 /****************************************************************************
 700  *
 701  * Level 2 implementation
 702  *
 703  ***************************************************************************/
 704
 705
 706 typedef struct FLAC__Metadata_Node {
 707         FLAC__StreamMetadata *data;
 708         struct FLAC__Metadata_Node *prev, *next;
 709 } FLAC__Metadata_Node;
 710
 711 struct FLAC__Metadata_Chain {
 712         char *filename;
 713         FLAC__Metadata_Node *head;
 714         FLAC__Metadata_Node *tail;
 715         unsigned nodes;
 716         FLAC__Metadata_ChainStatus status;
 717         long first_offset, last_offset; /*@@@ 2G limit */
 718         /*
 719          * This is the length of the chain initially read from the FLAC file.
 720          * it is used to compare against the current length to decide whether
 721          * or not the whole file has to be rewritten.
 722          */
 723         unsigned initial_length; /*@@@ 4G limit */
 724 };
 725
 726 struct FLAC__Metadata_Iterator {
 727         FLAC__Metadata_Chain *chain;
 728         FLAC__Metadata_Node *current;
 729 };
 730
 731 const char * const FLAC__Metadata_ChainStatusString[] = {
 732         "FLAC__METADATA_CHAIN_STATUS_OK",
 733         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 734         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 735         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 736         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 737         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 738         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 739         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 740         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 741         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 742         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 743         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 744         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR"
 745 };
 746
 747
 748 static FLAC__Metadata_Node *node_new_()
 749 {
 750         FLAC__Metadata_Node *node = (FLAC__Metadata_Node*)malloc(sizeof(FLAC__Metadata_Node));
 751         if(0 != node)
 752                 memset(node, 0, sizeof(FLAC__Metadata_Node));
 753         return node;
 754 }
 755
 756 static void node_delete_(FLAC__Metadata_Node *node)
 757 {
 758         FLAC__ASSERT(0 != node);
 759         if(0 != node->data)
 760                 FLAC__metadata_object_delete(node->data);
 761         free(node);
 762 }
 763
 764 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 765 {
 766         FLAC__ASSERT(0 != chain);
 767         FLAC__ASSERT(0 != node);
 768         FLAC__ASSERT(0 != node->data);
 769
 770         node->next = node->prev = 0;
 771         node->data->is_last = true;
 772         if(0 != chain->tail)
 773                 chain->tail->data->is_last = false;
 774
 775         if(0 == chain->head)
 776                 chain->head = node;
 777         else {
 778                 FLAC__ASSERT(0 != chain->tail);
 779                 chain->tail->next = node;
 780                 node->prev = chain->tail;
 781         }
 782         chain->tail = node;
 783         chain->nodes++;
 784 }
 785
 786 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 787 {
 788         FLAC__ASSERT(0 != chain);
 789         FLAC__ASSERT(0 != node);
 790
 791         if(node == chain->head)
 792                 chain->head = node->next;
 793         else
 794                 node->prev->next = node->next;
 795
 796         if(node == chain->tail)
 797                 chain->tail = node->prev;
 798         else
 799                 node->next->prev = node->prev;
 800
 801         if(0 != chain->tail)
 802                 chain->tail->data->is_last = true;
 803
 804         chain->nodes--;
 805 }
 806
 807 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 808 {
 809         chain_remove_node_(chain, node);
 810         node_delete_(node);
 811 }
 812
 813 static unsigned chain_calculate_length_(FLAC__Metadata_Chain *chain)
 814 {
 815         const FLAC__Metadata_Node *node;
 816         unsigned length = 0;
 817         for(node = chain->head; node; node = node->next)
 818                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 819         return length;
 820 }
 821
 822 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 823 {
 824         FLAC__ASSERT(0 != node);
 825         FLAC__ASSERT(0 != node->data);
 826         FLAC__ASSERT(0 != iterator);
 827         FLAC__ASSERT(0 != iterator->current);
 828         FLAC__ASSERT(0 != iterator->chain);
 829         FLAC__ASSERT(0 != iterator->chain->head);
 830         FLAC__ASSERT(0 != iterator->chain->tail);
 831
 832         node->data->is_last = false;
 833
 834         node->prev = iterator->current->prev;
 835         node->next = iterator->current;
 836
 837         if(0 == node->prev)
 838                 iterator->chain->head = node;
 839         else
 840                 node->prev->next = node;
 841
 842         iterator->current->prev = node;
 843
 844         iterator->chain->nodes++;
 845 }
 846
 847 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 848 {
 849         FLAC__ASSERT(0 != node);
 850         FLAC__ASSERT(0 != node->data);
 851         FLAC__ASSERT(0 != iterator);
 852         FLAC__ASSERT(0 != iterator->current);
 853         FLAC__ASSERT(0 != iterator->chain);
 854         FLAC__ASSERT(0 != iterator->chain->head);
 855         FLAC__ASSERT(0 != iterator->chain->tail);
 856
 857         iterator->current->data->is_last = false;
 858
 859         node->prev = iterator->current;
 860         node->next = iterator->current->next;
 861
 862         if(0 == node->next)
 863                 iterator->chain->tail = node;
 864         else
 865                 node->next->prev = node;
 866
 867         node->prev->next = node;
 868
 869         iterator->chain->tail->data->is_last = true;
 870
 871         iterator->chain->nodes++;
 872 }
 873
 874 /* return true iff node and node->next are both padding */
 875 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 876 {
 877         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
 878                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
 879                 node->data->length += growth;
 880
 881                 chain_delete_node_(chain, node->next);
 882                 return true;
 883         }
 884         else
 885                 return false;
 886 }
 887
 888 FLAC__Metadata_Chain *FLAC__metadata_chain_new()
 889 {
 890         FLAC__Metadata_Chain *chain = malloc(sizeof(FLAC__Metadata_Chain));
 891
 892         if(0 != chain) {
 893                 chain->filename = 0;
 894                 chain->head = chain->tail = 0;
 895                 chain->nodes = 0;
 896                 chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 897                 chain->initial_length = 0;
 898         }
 899
 900         return chain;
 901 }
 902
 903 void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
 904 {
 905         FLAC__Metadata_Node *node, *next;
 906
 907         FLAC__ASSERT(0 != chain);
 908
 909         for(node = chain->head; node; ) {
 910                 next = node->next;
 911                 node_delete_(node);
 912                 node = next;
 913         }
 914
 915         if(0 != chain->filename)
 916                 free(chain->filename);
 917
 918         free(chain);
 919 }
 920
 921 FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
 922 {
 923         FLAC__Metadata_ChainStatus status;
 924
 925         FLAC__ASSERT(0 != chain);
 926
 927         status = chain->status;
 928         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 929         return status;
 930 }
 931
 932 FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
 933 {
 934         FLAC__Metadata_SimpleIterator *iterator;
 935         FLAC__Metadata_Node *node;
 936
 937         FLAC__ASSERT(0 != chain);
 938         FLAC__ASSERT(0 != filename);
 939
 940         if(0 == (chain->filename = strdup(filename))) {
 941                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 942                 return false;
 943         }
 944
 945         if(0 == (iterator = FLAC__metadata_simple_iterator_new())) {
 946                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 947                 return false;
 948         }
 949
 950         if(!FLAC__metadata_simple_iterator_init(iterator, filename, /*preserve_file_stats=*/false)) {
 951                 chain->status = get_equivalent_status_(iterator->status);
 952                 return false;
 953         }
 954
 955         chain->first_offset = iterator->offset[iterator->depth];
 956
 957         do {
 958                 node = node_new_();
 959                 if(0 == node) {
 960                         chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 961                         return false;
 962                 }
 963                 node->data = FLAC__metadata_simple_iterator_get_block(iterator);
 964                 if(0 == node->data) {
 965                         node_delete_(node);
 966                         chain->status = get_equivalent_status_(iterator->status);
 967                         return false;
 968                 }
 969                 chain_append_node_(chain, node);
 970         } while(FLAC__metadata_simple_iterator_next(iterator));
 971
 972         if(!iterator->is_last || iterator->status != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK) {
 973                 chain->status = get_equivalent_status_(iterator->status);
 974                 return false;
 975         }
 976
 977         chain->last_offset = ftell(iterator->file) + iterator->length;
 978         FLAC__metadata_simple_iterator_delete(iterator);
 979
 980         chain->initial_length = chain_calculate_length_(chain);
 981         return true;
 982 }
 983
 984 FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
 985 {
 986         struct stat stats;
 987         const char *tempfile_path_prefix = 0;
 988         unsigned current_length;
 989
 990         FLAC__ASSERT(0 != chain);
 991
 992         current_length = chain_calculate_length_(chain);
 993
 994         if(use_padding) {
 995                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
 996                         const unsigned delta = chain->initial_length - current_length;
 997                         chain->tail->data->length += delta;
 998                         current_length += delta;
 999                         FLAC__ASSERT(current_length == chain->initial_length);
1000                 }
1001                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1002                         FLAC__StreamMetadata *padding;
1003                         FLAC__Metadata_Node *node;
1004                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1005                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1006                                 return false;
1007                         }
1008                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1009                         if(0 == (node = node_new_())) {
1010                                 FLAC__metadata_object_delete(padding);
1011                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1012                                 return false;
1013                         }
1014                         node->data = padding;
1015                         chain_append_node_(chain, node);
1016                         current_length = chain_calculate_length_(chain);
1017                         FLAC__ASSERT(current_length == chain->initial_length);
1018                 }
1019                 else if(current_length > chain->initial_length) {
1020                         const unsigned delta = current_length - chain->initial_length;
1021                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1022                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1023                                         chain_delete_node_(chain, chain->tail);
1024                                         current_length = chain_calculate_length_(chain);
1025                                         FLAC__ASSERT(current_length == chain->initial_length);
1026                                 }
1027                                 else if(chain->tail->data->length >= delta) {
1028                                         chain->tail->data->length -= delta;
1029                                         current_length -= delta;
1030                                         FLAC__ASSERT(current_length == chain->initial_length);
1031                                 }
1032                         }
1033                 }
1034         }
1035
1036         if(preserve_file_stats)
1037                 get_file_stats_(chain->filename, &stats);
1038
1039         if(current_length == chain->initial_length) {
1040                 if(!chain_rewrite_chain_(chain))
1041                         return false;
1042         }
1043         else {
1044                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1045                         return false;
1046         }
1047
1048         if(preserve_file_stats)
1049                 set_file_stats_(chain->filename, &stats);
1050
1051         /* recompute lengths and offsets if necessary */
1052         if(chain->initial_length != current_length) {
1053                 const FLAC__Metadata_Node *node;
1054                 chain->initial_length = current_length;
1055                 chain->last_offset = chain->first_offset;
1056                 for(node = chain->head; node; node = node->next)
1057                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1058         }
1059
1060         return true;
1061 }
1062
1063 void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1064 {
1065         FLAC__Metadata_Node *node;
1066
1067         FLAC__ASSERT(0 != chain);
1068
1069         for(node = chain->head; node; ) {
1070                 if(!chain_merge_adjacent_padding_(chain, node))
1071                         node = node->next;
1072         }
1073 }
1074
1075 void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1076 {
1077         FLAC__Metadata_Node *node, *save;
1078         unsigned i;
1079
1080         FLAC__ASSERT(0 != chain);
1081
1082         /*
1083          * Don't try and be too smart... this simple algo is good enough for
1084          * the small number of nodes that we deal with.
1085          */
1086         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1087                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1088                         save = node->next;
1089                         chain_remove_node_(chain, node);
1090                         chain_append_node_(chain, node);
1091                         node = save;
1092                 }
1093                 else {
1094                         node = node->next;
1095                 }
1096         }
1097
1098         FLAC__metadata_chain_merge_padding(chain);
1099 }
1100
1101
1102 FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1103 {
1104         FLAC__Metadata_Iterator *iterator = malloc(sizeof(FLAC__Metadata_Iterator));
1105
1106         if(0 != iterator) {
1107                 iterator->current = 0;
1108                 iterator->chain = 0;
1109         }
1110
1111         return iterator;
1112 }
1113
1114 void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1115 {
1116         FLAC__ASSERT(0 != iterator);
1117
1118         free(iterator);
1119 }
1120
1121 void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1122 {
1123         FLAC__ASSERT(0 != iterator);
1124         FLAC__ASSERT(0 != chain);
1125         FLAC__ASSERT(0 != chain->head);
1126
1127         iterator->chain = chain;
1128         iterator->current = chain->head;
1129 }
1130
1131 FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1132 {
1133         FLAC__ASSERT(0 != iterator);
1134
1135         if(0 == iterator->current || 0 == iterator->current->next)
1136                 return false;
1137
1138         iterator->current = iterator->current->next;
1139         return true;
1140 }
1141
1142 FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1143 {
1144         FLAC__ASSERT(0 != iterator);
1145
1146         if(0 == iterator->current || 0 == iterator->current->prev)
1147                 return false;
1148
1149         iterator->current = iterator->current->prev;
1150         return true;
1151 }
1152
1153 FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1154 {
1155         FLAC__ASSERT(0 != iterator);
1156         FLAC__ASSERT(0 != iterator->current);
1157         FLAC__ASSERT(0 != iterator->current->data);
1158
1159         return iterator->current->data->type;
1160 }
1161
1162 FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1163 {
1164         FLAC__ASSERT(0 != iterator);
1165         FLAC__ASSERT(0 != iterator->current);
1166
1167         return iterator->current->data;
1168 }
1169
1170 FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1171 {
1172         FLAC__ASSERT(0 != iterator);
1173         FLAC__ASSERT(0 != block);
1174         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1175 }
1176
1177 FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1178 {
1179         FLAC__Metadata_Node *save;
1180
1181         FLAC__ASSERT(0 != iterator);
1182         FLAC__ASSERT(0 != iterator->current);
1183
1184         if(0 == iterator->current->prev) {
1185                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1186                 return false;
1187         }
1188
1189         save = iterator->current->prev;
1190
1191         if(replace_with_padding) {
1192                 FLAC__metadata_object_delete_data(iterator->current->data);
1193                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1194         }
1195         else {
1196                 chain_delete_node_(iterator->chain, iterator->current);
1197         }
1198
1199         iterator->current = save;
1200         return true;
1201 }
1202
1203 FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1204 {
1205         FLAC__Metadata_Node *node;
1206
1207         FLAC__ASSERT(0 != iterator);
1208         FLAC__ASSERT(0 != iterator->current);
1209         FLAC__ASSERT(0 != block);
1210
1211         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1212                 return false;
1213
1214         if(0 == iterator->current->prev) {
1215                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1216                 return false;
1217         }
1218
1219         if(0 == (node = node_new_()))
1220                 return false;
1221
1222         node->data = block;
1223         iterator_insert_node_(iterator, node);
1224         iterator->current = node;
1225         return true;
1226 }
1227
1228 FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1229 {
1230         FLAC__Metadata_Node *node;
1231
1232         FLAC__ASSERT(0 != iterator);
1233         FLAC__ASSERT(0 != iterator->current);
1234         FLAC__ASSERT(0 != block);
1235
1236         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1237                 return false;
1238
1239         if(0 == (node = node_new_()))
1240                 return false;
1241
1242         node->data = block;
1243         iterator_insert_node_after_(iterator, node);
1244         iterator->current = node;
1245         return true;
1246 }
1247
1248
1249 /****************************************************************************
1250  *
1251  * Local function definitions
1252  *
1253  ***************************************************************************/
1254
1255 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1256 {
1257         unsigned i;
1258
1259         b += bytes;
1260
1261         for(i = 0; i < bytes; i++) {
1262                 *(--b) = (FLAC__byte)(val & 0xff);
1263                 val >>= 8;
1264         }
1265 }
1266
1267 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1268 {
1269         unsigned i;
1270
1271         for(i = 0; i < bytes; i++) {
1272                 *(b++) = (FLAC__byte)(val & 0xff);
1273                 val >>= 8;
1274         }
1275 }
1276
1277 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1278 {
1279         unsigned i;
1280
1281         b += bytes;
1282
1283         for(i = 0; i < bytes; i++) {
1284                 *(--b) = (FLAC__byte)(val & 0xff);
1285                 val >>= 8;
1286         }
1287 }
1288
1289 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1290 {
1291         FLAC__uint32 ret = 0;
1292         unsigned i;
1293
1294         for(i = 0; i < bytes; i++)
1295                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1296
1297         return ret;
1298 }
1299
1300 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1301 {
1302         FLAC__uint32 ret = 0;
1303         unsigned i;
1304
1305         b += bytes;
1306
1307         for(i = 0; i < bytes; i++)
1308                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1309
1310         return ret;
1311 }
1312
1313 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1314 {
1315         FLAC__uint64 ret = 0;
1316         unsigned i;
1317
1318         for(i = 0; i < bytes; i++)
1319                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1320
1321         return ret;
1322 }
1323
1324 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1325 {
1326         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1327
1328         FLAC__ASSERT(0 != iterator);
1329         FLAC__ASSERT(0 != iterator->file);
1330
1331         if(fread(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, iterator->file) != FLAC__STREAM_METADATA_HEADER_LENGTH) {
1332                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1333                 return false;
1334         }
1335
1336         iterator->is_last = raw_header[0] & 0x80? true : false;
1337         iterator->type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1338         iterator->length = unpack_uint32_(raw_header + 1, 3);
1339
1340         /* do some checking */
1341         if(iterator->type > FLAC__METADATA_TYPE_VORBIS_COMMENT) {
1342                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA;
1343                 return false;
1344         }
1345
1346         return true;
1347 }
1348
1349 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1350 {
1351         FLAC__ASSERT(0 != iterator);
1352         FLAC__ASSERT(0 != iterator->file);
1353
1354         switch(block->type) {
1355                 case FLAC__METADATA_TYPE_STREAMINFO:
1356                         iterator->status = read_metadata_block_data_streaminfo_(iterator->file, &block->data.stream_info);
1357                         break;
1358                 case FLAC__METADATA_TYPE_PADDING:
1359                         iterator->status = read_metadata_block_data_padding_(iterator->file, &block->data.padding, block->length);
1360                         break;
1361                 case FLAC__METADATA_TYPE_APPLICATION:
1362                         iterator->status = read_metadata_block_data_application_(iterator->file, &block->data.application, block->length);
1363                         break;
1364                 case FLAC__METADATA_TYPE_SEEKTABLE:
1365                         iterator->status = read_metadata_block_data_seektable_(iterator->file, &block->data.seek_table, block->length);
1366                         break;
1367                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1368                         iterator->status = read_metadata_block_data_vorbis_comment_(iterator->file, &block->data.vorbis_comment);
1369                         break;
1370                 default:
1371                         FLAC__ASSERT(0);
1372                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR;
1373         }
1374
1375         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1376 }
1377
1378 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_(FILE *file, FLAC__StreamMetadata_StreamInfo *block)
1379 {
1380         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1381
1382         FLAC__ASSERT(0 != file);
1383
1384         if(fread(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, file) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1385                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1386
1387         b = buffer;
1388
1389         /* @@@ we are using hardcoded numbers for simplicity but we should
1390          * probably eventually write a bit-level unpacker and use the
1391          * _STREAMINFO_ constants.
1392          */
1393         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1394         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1395         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1396         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1397         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1398         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1399         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 1) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1400         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1401         memcpy(block->md5sum, b+8, 16);
1402
1403         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1404 }
1405
1406
1407 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_(FILE *file, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1408 {
1409         FLAC__ASSERT(0 != file);
1410
1411         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1412
1413         if(0 != fseek(file, block_length, SEEK_CUR))
1414                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1415
1416         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1417 }
1418
1419 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_(FILE *file, FLAC__StreamMetadata_Application *block, unsigned block_length)
1420 {
1421         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1422
1423         FLAC__ASSERT(0 != file);
1424
1425         if(fread(block->id, 1, id_bytes, file) != id_bytes)
1426                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1427
1428         block_length -= id_bytes;
1429
1430         if(block_length == 0) {
1431                 block->data = 0;
1432         }
1433         else {
1434                 if(0 == (block->data = malloc(block_length)))
1435                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1436
1437                 if(fread(block->data, 1, block_length, file) != block_length)
1438                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1439         }
1440
1441         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1442 }
1443
1444 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_(FILE *file, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1445 {
1446         unsigned i;
1447         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1448
1449         FLAC__ASSERT(0 != file);
1450         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1451
1452         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1453
1454         if(block->num_points == 0)
1455                 block->points = 0;
1456         else if(0 == (block->points = malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1457                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1458
1459         for(i = 0; i < block->num_points; i++) {
1460                 if(fread(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, file) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1461                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1462                 /*@@@ some MAGIC NUMBERs here */
1463                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1464                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1465                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1466         }
1467
1468         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1469 }
1470
1471 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_(FILE *file, FLAC__StreamMetadata_VorbisComment_Entry *entry)
1472 {
1473         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1474         FLAC__byte buffer[4]; /* magic number is asserted below */
1475
1476         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == 4);
1477         FLAC__ASSERT(0 != file);
1478
1479         if(fread(buffer, 1, entry_length_len, file) != entry_length_len)
1480                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1481         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
1482
1483         if(entry->length == 0) {
1484                 entry->entry = 0;
1485         }
1486         else {
1487                 if(0 == (entry->entry = malloc(entry->length)))
1488                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1489
1490                 if(fread(entry->entry, 1, entry->length, file) != entry->length)
1491                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1492         }
1493
1494         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1495 }
1496
1497 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_(FILE *file, FLAC__StreamMetadata_VorbisComment *block)
1498 {
1499         unsigned i;
1500         FLAC__Metadata_SimpleIteratorStatus status;
1501         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1502         FLAC__byte buffer[4]; /* magic number is asserted below */
1503
1504         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == 4);
1505         FLAC__ASSERT(0 != file);
1506
1507         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_(file, &(block->vendor_string))))
1508                 return status;
1509
1510         if(fread(buffer, 1, num_comments_len, file) != num_comments_len)
1511                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1512         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
1513
1514         if(block->num_comments == 0) {
1515                 block->comments = 0;
1516         }
1517         else if(0 == (block->comments = malloc(block->num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
1518                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1519
1520         for(i = 0; i < block->num_comments; i++) {
1521                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_(file, block->comments + i)))
1522                         return status;
1523         }
1524
1525         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1526 }
1527
1528 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
1529 {
1530         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
1531
1532         FLAC__ASSERT(0 != file);
1533         FLAC__ASSERT(0 != status);
1534         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
1535
1536         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
1537         pack_uint32_(block->length, buffer + 1, 3);
1538
1539         if(fwrite(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, file) != FLAC__STREAM_METADATA_HEADER_LENGTH) {
1540                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1541                 return false;
1542         }
1543
1544         return true;
1545 }
1546
1547 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
1548 {
1549         FLAC__ASSERT(0 != file);
1550         FLAC__ASSERT(0 != status);
1551
1552         switch(block->type) {
1553                 case FLAC__METADATA_TYPE_STREAMINFO:
1554                         *status = write_metadata_block_data_streaminfo_(file, &block->data.stream_info);
1555                         break;
1556                 case FLAC__METADATA_TYPE_PADDING:
1557                         *status = write_metadata_block_data_padding_(file, &block->data.padding, block->length);
1558                         break;
1559                 case FLAC__METADATA_TYPE_APPLICATION:
1560                         *status = write_metadata_block_data_application_(file, &block->data.application, block->length);
1561                         break;
1562                 case FLAC__METADATA_TYPE_SEEKTABLE:
1563                         *status = write_metadata_block_data_seektable_(file, &block->data.seek_table);
1564                         break;
1565                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1566                         *status = write_metadata_block_data_vorbis_comment_(file, &block->data.vorbis_comment);
1567                         break;
1568                 default:
1569                         FLAC__ASSERT(0);
1570                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR;
1571         }
1572         return (*status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1573 }
1574
1575 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_streaminfo_(FILE *file, const FLAC__StreamMetadata_StreamInfo *block)
1576 {
1577         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
1578         const unsigned channels1 = block->channels - 1;
1579         const unsigned bps1 = block->bits_per_sample - 1;
1580
1581         FLAC__ASSERT(0 != file);
1582
1583         /* @@@ we are using hardcoded numbers for simplicity but we should
1584          * probably eventually write a bit-level packer and use the
1585          * _STREAMINFO_ constants.
1586          */
1587         pack_uint32_(block->min_blocksize, buffer, 2);
1588         pack_uint32_(block->max_blocksize, buffer+2, 2);
1589         pack_uint32_(block->min_framesize, buffer+4, 3);
1590         pack_uint32_(block->max_framesize, buffer+7, 3);
1591         buffer[10] = (block->sample_rate >> 12) & 0xff;
1592         buffer[11] = (block->sample_rate >> 4) & 0xff;
1593         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
1594         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
1595         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
1596         memcpy(buffer+18, block->md5sum, 16);
1597
1598         if(fwrite(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, file) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1599                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1600
1601         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1602 }
1603
1604 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_padding_(FILE *file, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
1605 {
1606         unsigned i, n = block_length;
1607         FLAC__byte buffer[1024];
1608
1609         FLAC__ASSERT(0 != file);
1610
1611         (void)block;
1612
1613         memset(buffer, 0, 1024);
1614
1615         for(i = 0; i < n/1024; i++)
1616                 if(fwrite(buffer, 1, 1024, file) != 1024)
1617                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1618
1619         n %= 1024;
1620
1621         if(fwrite(buffer, 1, n, file) != n)
1622                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1623
1624         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1625 }
1626
1627 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_application_(FILE *file, const FLAC__StreamMetadata_Application *block, unsigned block_length)
1628 {
1629         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1630
1631         FLAC__ASSERT(0 != file);
1632
1633         if(fwrite(block->id, 1, id_bytes, file) != id_bytes)
1634                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1635
1636         block_length -= id_bytes;
1637
1638         if(fwrite(block->data, 1, block_length, file) != block_length)
1639                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1640
1641         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1642 }
1643
1644 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_seektable_(FILE *file, const FLAC__StreamMetadata_SeekTable *block)
1645 {
1646         unsigned i;
1647         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1648
1649         FLAC__ASSERT(0 != file);
1650
1651         for(i = 0; i < block->num_points; i++) {
1652                 /*@@@ some MAGIC NUMBERs here */
1653                 pack_uint64_(block->points[i].sample_number, buffer, 8);
1654                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
1655                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
1656                 if(fwrite(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, file) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1657                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1658         }
1659
1660         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1661 }
1662
1663 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_vorbis_comment_(FILE *file, const FLAC__StreamMetadata_VorbisComment *block)
1664 {
1665         unsigned i;
1666         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1667         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1668         FLAC__byte buffer[4]; /* magic number is asserted below */
1669
1670         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == 4);
1671         FLAC__ASSERT(0 != file);
1672
1673         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
1674         if(fwrite(buffer, 1, entry_length_len, file) != entry_length_len)
1675                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1676         if(fwrite(block->vendor_string.entry, 1, block->vendor_string.length, file) != block->vendor_string.length)
1677                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1678
1679         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
1680         if(fwrite(buffer, 1, num_comments_len, file) != num_comments_len)
1681                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1682
1683         for(i = 0; i < block->num_comments; i++) {
1684                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
1685                 if(fwrite(buffer, 1, entry_length_len, file) != entry_length_len)
1686                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1687                 if(fwrite(block->comments[i].entry, 1, block->comments[i].length, file) != block->comments[i].length)
1688                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1689         }
1690
1691         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1692 }
1693
1694 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
1695 {
1696         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
1697                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1698                 return false;
1699         }
1700
1701         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
1702                 return false;
1703
1704         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
1705                 return false;
1706
1707         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
1708                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1709                 return false;
1710         }
1711
1712         return read_metadata_block_header_(iterator);
1713 }
1714
1715 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
1716 {
1717         FLAC__StreamMetadata *padding;
1718
1719         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
1720                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1721                 return false;
1722         }
1723
1724         block->is_last = false;
1725
1726         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
1727                 return false;
1728
1729         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
1730                 return false;
1731
1732         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
1733                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1734
1735         padding->is_last = padding_is_last;
1736         padding->length = padding_length;
1737
1738         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
1739                 FLAC__metadata_object_delete(padding);
1740                 return false;
1741         }
1742
1743         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
1744                 FLAC__metadata_object_delete(padding);
1745                 return false;
1746         }
1747
1748         FLAC__metadata_object_delete(padding);
1749
1750         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
1751                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1752                 return false;
1753         }
1754
1755         return read_metadata_block_header_(iterator);
1756 }
1757
1758 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
1759 {
1760         FILE *tempfile;
1761         char *tempfilename;
1762         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
1763         long fixup_is_last_flag_offset = -1;
1764
1765         FLAC__ASSERT(0 != block || append == false);
1766
1767         if(iterator->is_last) {
1768                 if(append) {
1769                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
1770                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
1771                 }
1772                 else if(0 == block) {
1773                         simple_iterator_push_(iterator);
1774                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
1775                                 (void)simple_iterator_pop_(iterator);
1776                                 return false;
1777                         }
1778                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
1779                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
1780                         if(!simple_iterator_pop_(iterator))
1781                                 return false;
1782                 }
1783         }
1784
1785         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
1786                 return false;
1787
1788         if(0 != block) {
1789                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
1790                         cleanup_tempfile_(&tempfile, &tempfilename);
1791                         return false;
1792                 }
1793
1794                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
1795                         cleanup_tempfile_(&tempfile, &tempfilename);
1796                         return false;
1797                 }
1798         }
1799
1800         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
1801                 return false;
1802
1803         if(append)
1804                 return FLAC__metadata_simple_iterator_next(iterator);
1805
1806         return true;
1807 }
1808
1809 FLAC__bool chain_rewrite_chain_(FLAC__Metadata_Chain *chain)
1810 {
1811         FILE *f;
1812         FLAC__Metadata_Node *node;
1813         FLAC__Metadata_SimpleIteratorStatus status;
1814
1815         FLAC__ASSERT(0 != chain);
1816         FLAC__ASSERT(0 != chain->filename);
1817         FLAC__ASSERT(0 != chain->head);
1818
1819         if(0 == (f = fopen(chain->filename, "r+b"))) {
1820                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1821                 return false;
1822         }
1823         if(0 != fseek(f, chain->first_offset, SEEK_SET)) {
1824                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1825                 return false;
1826         }
1827
1828         for(node = chain->head; node; node = node->next) {
1829                 if(!write_metadata_block_header_(f, &status, node->data)) {
1830                         chain->status = get_equivalent_status_(status);
1831                         return false;
1832                 }
1833                 if(!write_metadata_block_data_(f, &status, node->data)) {
1834                         chain->status = get_equivalent_status_(status);
1835                         return false;
1836                 }
1837         }
1838
1839         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1840
1841         (void)fclose(f);
1842
1843         return true;
1844 }
1845
1846 FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1847 {
1848         FILE *f, *tempfile;
1849         char *tempfilename;
1850         FLAC__Metadata_SimpleIteratorStatus status;
1851         const FLAC__Metadata_Node *node;
1852
1853         FLAC__ASSERT(0 != chain);
1854         FLAC__ASSERT(0 != chain->filename);
1855         FLAC__ASSERT(0 != chain->head);
1856
1857         /* copy the file prefix (data up to first metadata block */
1858         if(0 == (f = fopen(chain->filename, "rb"))) {
1859                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1860                 return false;
1861         }
1862         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1863                 chain->status = get_equivalent_status_(status);
1864                 cleanup_tempfile_(&tempfile, &tempfilename);
1865                 return false;
1866         }
1867         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1868                 chain->status = get_equivalent_status_(status);
1869                 cleanup_tempfile_(&tempfile, &tempfilename);
1870                 return false;
1871         }
1872
1873         /* write the metadata */
1874         for(node = chain->head; node; node = node->next) {
1875                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1876                         chain->status = get_equivalent_status_(status);
1877                         return false;
1878                 }
1879                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1880                         chain->status = get_equivalent_status_(status);
1881                         return false;
1882                 }
1883         }
1884         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1885
1886         /* copy the file postfix (everything after the metadata) */
1887         if(0 != fseek(f, chain->last_offset, SEEK_SET)) {
1888                 cleanup_tempfile_(&tempfile, &tempfilename);
1889                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1890                 return false;
1891         }
1892         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1893                 cleanup_tempfile_(&tempfile, &tempfilename);
1894                 chain->status = get_equivalent_status_(status);
1895                 return false;
1896         }
1897
1898         /* move the tempfile on top of the original */
1899         (void)fclose(f);
1900         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1901                 return false;
1902
1903         return true;
1904 }
1905
1906 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
1907 {
1908         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
1909         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
1910         iterator->depth++;
1911 }
1912
1913 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
1914 {
1915         FLAC__ASSERT(iterator->depth > 0);
1916         iterator->depth--;
1917         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
1918                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1919                 return false;
1920         }
1921
1922         return read_metadata_block_header_(iterator);
1923 }
1924
1925 unsigned seek_to_first_metadata_block_(FILE *f)
1926 {
1927         FLAC__byte buffer[4];
1928         size_t n;
1929         unsigned i;
1930
1931         FLAC__ASSERT(0 != f);
1932         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == 4);
1933
1934         /* skip any id3v2 tag */
1935 #if !defined _MSC_VER && !defined __MINGW32__
1936 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
1937         errno = 0;
1938 #endif
1939         n = fread(buffer, 1, 4, f);
1940 #if !defined _MSC_VER && !defined __MINGW32__
1941 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
1942         if(errno)
1943                 return 1;
1944         else
1945 #endif
1946         if(n != 4)
1947                 return 2;
1948         else if(0 == memcmp(buffer, "ID3", 3)) {
1949                 unsigned tag_length = 0;
1950
1951                 /* skip to the tag length */
1952                 if(fseek(f, 2, SEEK_CUR) < 0)
1953                         return 1;
1954
1955                 /* read the length */
1956                 for(i = 0; i < 4; i++) {
1957                         if(fread(buffer, 1, 1, f) < 1 || buffer[0] & 0x80)
1958                                 return 1;
1959                         tag_length <<= 7;
1960                         tag_length |= (buffer[0] & 0x7f);
1961                 }
1962
1963                 /* skip the rest of the tag */
1964                 if(fseek(f, tag_length, SEEK_CUR) < 0)
1965                         return 1;
1966
1967                 /* read the stream sync code */
1968 #if !defined _MSC_VER && !defined __MINGW32__
1969 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
1970                 errno = 0;
1971 #endif
1972                 n = fread(buffer, 1, 4, f);
1973 #if !defined _MSC_VER && !defined __MINGW32__
1974 /*@@@ don't know how to resolve errno without using LIBC.LIB; must use MSVCRT.LIB only for plugins */
1975                 if(errno)
1976                         return 1;
1977                 else
1978 #endif
1979                 if(n != 4)
1980                         return 2;
1981         }
1982
1983         /* check for the fLaC signature */
1984         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
1985                 return 0;
1986         else
1987                 return 2;
1988 }
1989
1990 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
1991 {
1992         const long offset_end = append? iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length : iterator->offset[iterator->depth];
1993
1994         if(0 != fseek(iterator->file, 0, SEEK_SET)) {
1995                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1996                 return false;
1997         }
1998         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
1999                 cleanup_tempfile_(tempfile, tempfilename);
2000                 return false;
2001         }
2002         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2003                 cleanup_tempfile_(tempfile, tempfilename);
2004                 return false;
2005         }
2006
2007         return true;
2008 }
2009
2010 FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, long fixup_is_last_flag_offset, FLAC__bool backup)
2011 {
2012         long save_offset = iterator->offset[iterator->depth]; /*@@@ 2G limit */
2013         FLAC__ASSERT(0 != *tempfile);
2014
2015         if(0 != fseek(iterator->file, save_offset + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length, SEEK_SET)) {
2016                 cleanup_tempfile_(tempfile, tempfilename);
2017                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2018                 return false;
2019         }
2020         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2021                 cleanup_tempfile_(tempfile, tempfilename);
2022                 return false;
2023         }
2024
2025         if(fixup_is_last_code != 0) {
2026                 /*
2027                  * if code == 1, it means a block was appended to the end so
2028                  *   we have to clear the is_last flag of the previous block
2029                  * if code == -1, it means the last block was deleted so
2030                  *   we have to set the is_last flag of the previous block
2031                  */
2032                 /*@@@ MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2033                 FLAC__byte x;
2034                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2035                         cleanup_tempfile_(tempfile, tempfilename);
2036                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2037                         return false;
2038                 }
2039                 if(fread(&x, 1, 1, *tempfile) != 1) {
2040                         cleanup_tempfile_(tempfile, tempfilename);
2041                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2042                         return false;
2043                 }
2044                 if(fixup_is_last_code > 0) {
2045                         FLAC__ASSERT(x & 0x80);
2046                         x &= 0x7f;
2047                 }
2048                 else {
2049                         FLAC__ASSERT(!(x & 0x80));
2050                         x |= 0x80;
2051                 }
2052                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2053                         cleanup_tempfile_(tempfile, tempfilename);
2054                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2055                         return false;
2056                 }
2057                 if(fwrite(&x, 1, 1, *tempfile) != 1) {
2058                         cleanup_tempfile_(tempfile, tempfilename);
2059                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2060                         return false;
2061                 }
2062         }
2063
2064         (void)fclose(iterator->file);
2065
2066         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2067                 return false;
2068
2069         if(iterator->has_stats)
2070                 set_file_stats_(iterator->filename, &iterator->stats);
2071
2072         if(!simple_iterator_prime_input_(iterator))
2073                 return false;
2074         if(backup) {
2075                 while(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length < save_offset)
2076                         if(!FLAC__metadata_simple_iterator_next(iterator))
2077                                 return false;
2078                 return true;
2079         }
2080         else {
2081                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2082                 FLAC__ASSERT(iterator->depth == 0);
2083                 iterator->offset[0] = save_offset;
2084                 iterator->depth++;
2085                 return simple_iterator_pop_(iterator);
2086         }
2087 }
2088
2089 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status)
2090 {
2091         FLAC__byte buffer[8192];
2092         unsigned n;
2093
2094         while(bytes > 0) {
2095                 n = min(sizeof(buffer), bytes);
2096                 if(fread(buffer, 1, n, file) != n) {
2097                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2098                         return false;
2099                 }
2100                 if(fwrite(buffer, 1, n, tempfile) != n) {
2101                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2102                         return false;
2103                 }
2104                 bytes -= n;
2105         }
2106
2107         return true;
2108 }
2109
2110 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2111 {
2112         FLAC__byte buffer[8192];
2113         size_t n;
2114
2115         while(!feof(file)) {
2116                 n = fread(buffer, 1, sizeof(buffer), file);
2117                 if(n == 0 && !feof(file)) {
2118                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2119                         return false;
2120                 }
2121                 if(n > 0 && fwrite(buffer, 1, n, tempfile) != n) {
2122                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2123                         return false;
2124                 }
2125         }
2126
2127         return true;
2128 }
2129
2130 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2131 {
2132         static const char *tempfile_suffix = ".metadata_edit";
2133         if(0 == tempfile_path_prefix) {
2134                 if(0 == (*tempfilename = malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
2135                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2136                         return false;
2137                 }
2138                 strcpy(*tempfilename, filename);
2139                 strcat(*tempfilename, tempfile_suffix);
2140         }
2141         else {
2142                 const char *p = strrchr(filename, '/');
2143                 if(0 == p)
2144                         p = filename;
2145                 else
2146                         p++;
2147
2148                 if(0 == (*tempfilename = malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
2149                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2150                         return false;
2151                 }
2152                 strcpy(*tempfilename, tempfile_path_prefix);
2153                 strcat(*tempfilename, "/");
2154                 strcat(*tempfilename, p);
2155                 strcat(*tempfilename, tempfile_suffix);
2156         }
2157
2158         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
2159                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
2160                 return false;
2161         }
2162
2163         return true;
2164 }
2165
2166 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2167 {
2168         FLAC__ASSERT(0 != filename);
2169         FLAC__ASSERT(0 != tempfile);
2170         FLAC__ASSERT(0 != *tempfile);
2171         FLAC__ASSERT(0 != tempfilename);
2172         FLAC__ASSERT(0 != *tempfilename);
2173         FLAC__ASSERT(0 != status);
2174
2175         (void)fclose(*tempfile);
2176         *tempfile = 0;
2177
2178 #if defined _MSC_VER || defined __MINGW32__
2179         if(unlink(filename) < 0) {
2180                 cleanup_tempfile_(tempfile, tempfilename);
2181                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
2182                 return false;
2183         }
2184 #endif
2185
2186         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
2187         if(0 != rename(*tempfilename, filename)) {
2188                 cleanup_tempfile_(tempfile, tempfilename);
2189                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
2190                 return false;
2191         }
2192
2193         cleanup_tempfile_(tempfile, tempfilename);
2194
2195         return true;
2196 }
2197
2198 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
2199 {
2200         if(0 != *tempfile) {
2201                 (void)fclose(*tempfile);
2202                 *tempfile = 0;
2203         }
2204
2205         if(0 != *tempfilename) {
2206                 (void)unlink(*tempfilename);
2207                 free(*tempfilename);
2208                 *tempfilename = 0;
2209         }
2210 }
2211
2212 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
2213 {
2214         FLAC__ASSERT(0 != filename);
2215         FLAC__ASSERT(0 != stats);
2216         return (0 == stat(filename, stats));
2217 }
2218
2219 void set_file_stats_(const char *filename, struct stat *stats)
2220 {
2221         struct utimbuf srctime;
2222
2223         FLAC__ASSERT(0 != filename);
2224         FLAC__ASSERT(0 != stats);
2225
2226         srctime.actime = stats->st_atime;
2227         srctime.modtime = stats->st_mtime;
2228         (void)chmod(filename, stats->st_mode);
2229         (void)utime(filename, &srctime);
2230 #if !defined _MSC_VER && !defined __MINGW32__
2231         (void)chown(filename, stats->st_uid, -1);
2232         (void)chown(filename, -1, stats->st_gid);
2233 #endif
2234 }
2235
2236 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
2237 {
2238         switch(status) {
2239                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
2240                         return FLAC__METADATA_CHAIN_STATUS_OK;
2241                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
2242                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
2243                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
2244                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2245                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
2246                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
2247                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
2248                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
2249                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
2250                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
2251                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
2252                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
2253                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
2254                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2255                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
2256                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
2257                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
2258                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
2259                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
2260                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
2261                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
2262                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
2263                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
2264                 default:
2265                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
2266         }
2267 }