src/libFLAC/metadata_iterators.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2001,2002,2003,2004  Josh Coalson
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * - Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * - Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * - Neither the name of the Xiph.org Foundation nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <errno.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #if defined _MSC_VER || defined __MINGW32__
  38 #include <sys/utime.h> /* for utime() */
  39 #include <io.h> /* for chmod() */
  40 #else
  41 #include <sys/types.h> /* some flavors of BSD (like OS X) require this to get time_t */
  42 #include <utime.h> /* for utime() */
  43 #include <unistd.h> /* for chown(), unlink() */
  44 #endif
  45 #include <sys/stat.h> /* for stat(), maybe chmod() */
  46
  47 #include "private/metadata.h"
  48
  49 #include "FLAC/assert.h"
  50 #include "FLAC/file_decoder.h"
  51
  52 #ifdef max
  53 #undef max
  54 #endif
  55 #define max(a,b) ((a)>(b)?(a):(b))
  56 #ifdef min
  57 #undef min
  58 #endif
  59 #define min(a,b) ((a)<(b)?(a):(b))
  60
  61
  62 /****************************************************************************
  63  *
  64  * Local function declarations
  65  *
  66  ***************************************************************************/
  67
  68 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  69 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  70 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
  71 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
  72 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
  73 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
  74
  75 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
  76 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
  77 static FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length);
  78 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block);
  79 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block);
  80 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length);
  81 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length);
  82 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length);
  83 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry);
  84 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block);
  85 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track);
  86 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block);
  87 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length);
  88
  89 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  90 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  91 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_streaminfo_(FILE *file, const FLAC__StreamMetadata_StreamInfo *block);
  92 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_padding_(FILE *file, const FLAC__StreamMetadata_Padding *block, unsigned block_length);
  93 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_application_(FILE *file, const FLAC__StreamMetadata_Application *block, unsigned block_length);
  94 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_seektable_(FILE *file, const FLAC__StreamMetadata_SeekTable *block);
  95 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_vorbis_comment_(FILE *file, const FLAC__StreamMetadata_VorbisComment *block);
  96 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_cuesheet_(FILE *file, const FLAC__StreamMetadata_CueSheet *block);
  97 static FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_unknown_(FILE *file, const FLAC__StreamMetadata_Unknown *block, unsigned block_length);
  98 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
  99 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
 100 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
 101
 102 static FLAC__bool chain_rewrite_chain_(FLAC__Metadata_Chain *chain);
 103 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix);
 104
 105 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
 106 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
 107
 108 /* return 0 if OK, 1 if read error, 2 if not a FLAC file */
 109 static unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb);
 110 static unsigned seek_to_first_metadata_block_(FILE *f);
 111
 112 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
 113 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);
 114
 115 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status);
 116 static FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status);
 117
 118 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 119 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 120 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
 121
 122 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats);
 123 static void set_file_stats_(const char *filename, struct stat *stats);
 124
 125 static int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence);
 126 static FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle);
 127
 128 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
 129
 130
 131 #ifdef FLAC__VALGRIND_TESTING
 132 static size_t local__fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
 133 {
 134         size_t ret = fwrite(ptr, size, nmemb, stream);
 135         if(!ferror(stream))
 136                 fflush(stream);
 137         return ret;
 138 }
 139 #else
 140 #define local__fwrite fwrite
 141 #endif
 142
 143 /****************************************************************************
 144  *
 145  * Level 0 implementation
 146  *
 147  ***************************************************************************/
 148
 149 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
 150 static void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
 151 static void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
 152
 153 typedef struct {
 154         FLAC__bool got_error;
 155         FLAC__bool got_streaminfo;
 156         FLAC__StreamMetadata *streaminfo;
 157 } level0_client_data;
 158
 159 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 160 {
 161         level0_client_data cd;
 162         FLAC__FileDecoder *decoder;
 163
 164         FLAC__ASSERT(0 != filename);
 165         FLAC__ASSERT(0 != streaminfo);
 166
 167         decoder = FLAC__file_decoder_new();
 168
 169         if(0 == decoder)
 170                 return false;
 171
 172         cd.got_error = false;
 173         cd.got_streaminfo = false;
 174         cd.streaminfo = streaminfo;
 175
 176         FLAC__file_decoder_set_md5_checking(decoder, false);
 177         FLAC__file_decoder_set_filename(decoder, filename);
 178         FLAC__file_decoder_set_metadata_ignore_all(decoder);
 179         FLAC__file_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO);
 180         FLAC__file_decoder_set_write_callback(decoder, write_callback_);
 181         FLAC__file_decoder_set_metadata_callback(decoder, metadata_callback_);
 182         FLAC__file_decoder_set_error_callback(decoder, error_callback_);
 183         FLAC__file_decoder_set_client_data(decoder, &cd);
 184
 185         if(FLAC__file_decoder_init(decoder) != FLAC__FILE_DECODER_OK || cd.got_error) {
 186                 FLAC__file_decoder_finish(decoder);
 187                 FLAC__file_decoder_delete(decoder);
 188                 return false;
 189         }
 190
 191         /* the first thing decoded must be the STREAMINFO block: */
 192         if(!FLAC__file_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
 193                 FLAC__file_decoder_finish(decoder);
 194                 FLAC__file_decoder_delete(decoder);
 195                 return false;
 196         }
 197
 198         FLAC__file_decoder_finish(decoder);
 199         FLAC__file_decoder_delete(decoder);
 200
 201         return !cd.got_error && cd.got_streaminfo;
 202 }
 203
 204 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 205 {
 206         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 207
 208         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 209 }
 210
 211 void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 212 {
 213         level0_client_data *cd = (level0_client_data *)client_data;
 214         (void)decoder;
 215
 216         if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO && 0 != cd->streaminfo) {
 217                 *(cd->streaminfo) = *metadata;
 218                 cd->got_streaminfo = true;
 219         }
 220 }
 221
 222 void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 223 {
 224         level0_client_data *cd = (level0_client_data *)client_data;
 225         (void)decoder;
 226
 227         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 228                 cd->got_error = true;
 229 }
 230
 231
 232 /****************************************************************************
 233  *
 234  * Level 1 implementation
 235  *
 236  ***************************************************************************/
 237
 238 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 239 /* 1 for initial offset, +4 for our own personal use */
 240
 241 struct FLAC__Metadata_SimpleIterator {
 242         FILE *file;
 243         char *filename, *tempfile_path_prefix;
 244         struct stat stats;
 245         FLAC__bool has_stats;
 246         FLAC__bool is_writable;
 247         FLAC__Metadata_SimpleIteratorStatus status;
 248         /*@@@ 2G limits here because of the offset type: */
 249         long offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 250         long first_offset; /* this is the offset to the STREAMINFO block */
 251         unsigned depth;
 252         /* this is the metadata block header of the current block we are pointing to: */
 253         FLAC__bool is_last;
 254         FLAC__MetadataType type;
 255         unsigned length;
 256 };
 257
 258 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 259         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 260         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 261         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 262         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 263         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 264         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 265         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 266         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 267         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 268         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 269         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 270         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 271         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 272 };
 273
 274
 275 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 276 {
 277         FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 278
 279         if(0 != iterator) {
 280                 iterator->file = 0;
 281                 iterator->filename = 0;
 282                 iterator->tempfile_path_prefix = 0;
 283                 iterator->has_stats = false;
 284                 iterator->is_writable = false;
 285                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 286                 iterator->first_offset = iterator->offset[0] = -1;
 287                 iterator->depth = 0;
 288         }
 289
 290         return iterator;
 291 }
 292
 293 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 294 {
 295         FLAC__ASSERT(0 != iterator);
 296
 297         if(0 != iterator->file) {
 298                 fclose(iterator->file);
 299                 iterator->file = 0;
 300                 if(iterator->has_stats)
 301                         set_file_stats_(iterator->filename, &iterator->stats);
 302         }
 303         if(0 != iterator->filename) {
 304                 free(iterator->filename);
 305                 iterator->filename = 0;
 306         }
 307         if(0 != iterator->tempfile_path_prefix) {
 308                 free(iterator->tempfile_path_prefix);
 309                 iterator->tempfile_path_prefix = 0;
 310         }
 311 }
 312
 313 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 314 {
 315         FLAC__ASSERT(0 != iterator);
 316
 317         simple_iterator_free_guts_(iterator);
 318         free(iterator);
 319 }
 320
 321 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 322 {
 323         FLAC__Metadata_SimpleIteratorStatus status;
 324
 325         FLAC__ASSERT(0 != iterator);
 326
 327         status = iterator->status;
 328         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 329         return status;
 330 }
 331
 332 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
 333 {
 334         unsigned ret;
 335
 336         FLAC__ASSERT(0 != iterator);
 337
 338         if(read_only || 0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 339                 iterator->is_writable = false;
 340                 if(read_only || errno == EACCES) {
 341                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 342                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 343                                 return false;
 344                         }
 345                 }
 346                 else {
 347                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 348                         return false;
 349                 }
 350         }
 351         else {
 352                 iterator->is_writable = true;
 353         }
 354
 355         ret = seek_to_first_metadata_block_(iterator->file);
 356         switch(ret) {
 357                 case 0:
 358                         iterator->depth = 0;
 359                         iterator->first_offset = iterator->offset[iterator->depth] = ftell(iterator->file);
 360                         return read_metadata_block_header_(iterator);
 361                 case 1:
 362                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 363                         return false;
 364                 case 2:
 365                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 366                         return false;
 367                 case 3:
 368                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 369                         return false;
 370                 default:
 371                         FLAC__ASSERT(0);
 372                         return false;
 373         }
 374 }
 375
 376 #if 0
 377 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 378 /*
 379  * The 'tempfile_path_prefix' allows you to specify a directory where
 380  * tempfiles should go.  Remember that if your metadata edits cause the
 381  * FLAC file to grow, the entire file will have to be rewritten.  If
 382  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 383  * same directory as the original FLAC file.  This makes replacing the
 384  * original with the tempfile fast but requires extra space in the same
 385  * partition for the tempfile.  If space is a problem, you can pass a
 386  * directory name belonging to a different partition in
 387  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 388  * '/' as the directory separator.  A trailing slash is not needed; it
 389  * will be added automatically.
 390  */
 391 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 392 #endif
 393
 394 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool read_only, FLAC__bool preserve_file_stats)
 395 {
 396         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 397
 398         FLAC__ASSERT(0 != iterator);
 399         FLAC__ASSERT(0 != filename);
 400
 401         simple_iterator_free_guts_(iterator);
 402
 403         if(!read_only && preserve_file_stats)
 404                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 405
 406         if(0 == (iterator->filename = strdup(filename))) {
 407                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 408                 return false;
 409         }
 410         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 411                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 412                 return false;
 413         }
 414
 415         return simple_iterator_prime_input_(iterator, read_only);
 416 }
 417
 418 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 419 {
 420         FLAC__ASSERT(0 != iterator);
 421         FLAC__ASSERT(0 != iterator->file);
 422
 423         return iterator->is_writable;
 424 }
 425
 426 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 427 {
 428         FLAC__ASSERT(0 != iterator);
 429         FLAC__ASSERT(0 != iterator->file);
 430
 431         if(iterator->is_last)
 432                 return false;
 433
 434         if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 435                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 436                 return false;
 437         }
 438
 439         iterator->offset[iterator->depth] = ftell(iterator->file);
 440
 441         return read_metadata_block_header_(iterator);
 442 }
 443
 444 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 445 {
 446         long this_offset;
 447
 448         FLAC__ASSERT(0 != iterator);
 449         FLAC__ASSERT(0 != iterator->file);
 450
 451         if(iterator->offset[iterator->depth] == iterator->first_offset)
 452                 return false;
 453
 454         if(0 != fseek(iterator->file, iterator->first_offset, SEEK_SET)) {
 455                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 456                 return false;
 457         }
 458         this_offset = iterator->first_offset;
 459         if(!read_metadata_block_header_(iterator))
 460                 return false;
 461
 462         /* we ignore any error from ftell() and catch it in fseek() */
 463         while(ftell(iterator->file) + (long)iterator->length < iterator->offset[iterator->depth]) {
 464                 if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 465                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 466                         return false;
 467                 }
 468                 this_offset = ftell(iterator->file);
 469                 if(!read_metadata_block_header_(iterator))
 470                         return false;
 471         }
 472
 473         iterator->offset[iterator->depth] = this_offset;
 474
 475         return true;
 476 }
 477
 478 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 479 {
 480         FLAC__ASSERT(0 != iterator);
 481         FLAC__ASSERT(0 != iterator->file);
 482
 483         return iterator->type;
 484 }
 485
 486 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 487 {
 488         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 489
 490         FLAC__ASSERT(0 != iterator);
 491         FLAC__ASSERT(0 != iterator->file);
 492
 493         if(0 != block) {
 494                 block->is_last = iterator->is_last;
 495                 block->length = iterator->length;
 496
 497                 if(!read_metadata_block_data_(iterator, block)) {
 498                         FLAC__metadata_object_delete(block);
 499                         return 0;
 500                 }
 501
 502                 /* back up to the beginning of the block data to stay consistent */
 503                 if(0 != fseek(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 504                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 505                         FLAC__metadata_object_delete(block);
 506                         return 0;
 507                 }
 508         }
 509         else
 510                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 511
 512         return block;
 513 }
 514
 515 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 516 {
 517         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 518         FLAC__bool ret;
 519
 520         FLAC__ASSERT(0 != iterator);
 521         FLAC__ASSERT(0 != iterator->file);
 522         FLAC__ASSERT(0 != block);
 523
 524         if(!iterator->is_writable) {
 525                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 526                 return false;
 527         }
 528
 529         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 530                 if(iterator->type != block->type) {
 531                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 532                         return false;
 533                 }
 534         }
 535
 536         block->is_last = iterator->is_last;
 537
 538         if(iterator->length == block->length)
 539                 return write_metadata_block_stationary_(iterator, block);
 540         else if(iterator->length > block->length) {
 541                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 542                         ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 543                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 544                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 545                         return ret;
 546                 }
 547                 else {
 548                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 549                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 550                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 551                         return ret;
 552                 }
 553         }
 554         else /* iterator->length < block->length */ {
 555                 unsigned padding_leftover = 0;
 556                 FLAC__bool padding_is_last = false;
 557                 if(use_padding) {
 558                         /* first see if we can even use padding */
 559                         if(iterator->is_last) {
 560                                 use_padding = false;
 561                         }
 562                         else {
 563                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 564                                 simple_iterator_push_(iterator);
 565                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 566                                         (void)simple_iterator_pop_(iterator);
 567                                         return false;
 568                                 }
 569                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 570                                         use_padding = false;
 571                                 }
 572                                 else {
 573                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 574                                                 padding_leftover = 0;
 575                                                 block->is_last = iterator->is_last;
 576                                         }
 577                                         else if(iterator->length < extra_padding_bytes_required)
 578                                                 use_padding = false;
 579                                         else {
 580                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 581                                                 padding_is_last = iterator->is_last;
 582                                                 block->is_last = false;
 583                                         }
 584                                 }
 585                                 if(!simple_iterator_pop_(iterator))
 586                                         return false;
 587                         }
 588                 }
 589                 if(use_padding) {
 590                         if(padding_leftover == 0) {
 591                                 ret = write_metadata_block_stationary_(iterator, block);
 592                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 593                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 594                                 return ret;
 595                         }
 596                         else {
 597                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 598                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 599                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 600                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 601                                 return ret;
 602                         }
 603                 }
 604                 else {
 605                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 606                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 607                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 608                         return ret;
 609                 }
 610         }
 611 }
 612
 613 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 614 {
 615         unsigned padding_leftover = 0;
 616         FLAC__bool padding_is_last = false;
 617
 618         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 619         FLAC__bool ret;
 620
 621         FLAC__ASSERT(0 != iterator);
 622         FLAC__ASSERT(0 != iterator->file);
 623         FLAC__ASSERT(0 != block);
 624
 625         if(!iterator->is_writable)
 626                 return false;
 627
 628         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 629                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 630                 return false;
 631         }
 632
 633         block->is_last = iterator->is_last;
 634
 635         if(use_padding) {
 636                 /* first see if we can even use padding */
 637                 if(iterator->is_last) {
 638                         use_padding = false;
 639                 }
 640                 else {
 641                         simple_iterator_push_(iterator);
 642                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 643                                 (void)simple_iterator_pop_(iterator);
 644                                 return false;
 645                         }
 646                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 647                                 use_padding = false;
 648                         }
 649                         else {
 650                                 if(iterator->length == block->length) {
 651                                         padding_leftover = 0;
 652                                         block->is_last = iterator->is_last;
 653                                 }
 654                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 655                                         use_padding = false;
 656                                 else {
 657                                         padding_leftover = iterator->length - block->length;
 658                                         padding_is_last = iterator->is_last;
 659                                         block->is_last = false;
 660                                 }
 661                         }
 662                         if(!simple_iterator_pop_(iterator))
 663                                 return false;
 664                 }
 665         }
 666         if(use_padding) {
 667                 /* move to the next block, which is suitable padding */
 668                 if(!FLAC__metadata_simple_iterator_next(iterator))
 669                         return false;
 670                 if(padding_leftover == 0) {
 671                         ret = write_metadata_block_stationary_(iterator, block);
 672                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 673                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 674                         return ret;
 675                 }
 676                 else {
 677                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 678                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 679                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 680                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 681                         return ret;
 682                 }
 683         }
 684         else {
 685                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 686                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 687                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 688                 return ret;
 689         }
 690 }
 691
 692 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 693 {
 694         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 695         FLAC__bool ret;
 696
 697         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 698                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 699                 return false;
 700         }
 701
 702         if(use_padding) {
 703                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 704                 if(0 == padding) {
 705                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 706                         return false;
 707                 }
 708                 padding->length = iterator->length;
 709                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 710                         FLAC__metadata_object_delete(padding);
 711                         return false;
 712                 }
 713                 FLAC__metadata_object_delete(padding);
 714                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 715                         return false;
 716                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 717                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 718                 return true;
 719         }
 720         else {
 721                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 722                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 723                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 724                 return ret;
 725         }
 726 }
 727
 728
 729
 730 /****************************************************************************
 731  *
 732  * Level 2 implementation
 733  *
 734  ***************************************************************************/
 735
 736
 737 typedef struct FLAC__Metadata_Node {
 738         FLAC__StreamMetadata *data;
 739         struct FLAC__Metadata_Node *prev, *next;
 740 } FLAC__Metadata_Node;
 741
 742 struct FLAC__Metadata_Chain {
 743         char *filename;
 744         FLAC__Metadata_Node *head;
 745         FLAC__Metadata_Node *tail;
 746         unsigned nodes;
 747         FLAC__Metadata_ChainStatus status;
 748         long first_offset, last_offset; /*@@@ 2G limit */
 749         /*
 750          * This is the length of the chain initially read from the FLAC file.
 751          * it is used to compare against the current length to decide whether
 752          * or not the whole file has to be rewritten.
 753          */
 754         unsigned initial_length; /*@@@ 4G limit */
 755 };
 756
 757 struct FLAC__Metadata_Iterator {
 758         FLAC__Metadata_Chain *chain;
 759         FLAC__Metadata_Node *current;
 760 };
 761
 762 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 763         "FLAC__METADATA_CHAIN_STATUS_OK",
 764         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 765         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 766         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 767         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 768         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 769         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 770         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 771         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 772         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 773         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 774         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 775         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR"
 776 };
 777
 778
 779 static FLAC__Metadata_Node *node_new_()
 780 {
 781         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 782 }
 783
 784 static void node_delete_(FLAC__Metadata_Node *node)
 785 {
 786         FLAC__ASSERT(0 != node);
 787         if(0 != node->data)
 788                 FLAC__metadata_object_delete(node->data);
 789         free(node);
 790 }
 791
 792 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 793 {
 794         FLAC__ASSERT(0 != chain);
 795         FLAC__ASSERT(0 != node);
 796         FLAC__ASSERT(0 != node->data);
 797
 798         node->next = node->prev = 0;
 799         node->data->is_last = true;
 800         if(0 != chain->tail)
 801                 chain->tail->data->is_last = false;
 802
 803         if(0 == chain->head)
 804                 chain->head = node;
 805         else {
 806                 FLAC__ASSERT(0 != chain->tail);
 807                 chain->tail->next = node;
 808                 node->prev = chain->tail;
 809         }
 810         chain->tail = node;
 811         chain->nodes++;
 812 }
 813
 814 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 815 {
 816         FLAC__ASSERT(0 != chain);
 817         FLAC__ASSERT(0 != node);
 818
 819         if(node == chain->head)
 820                 chain->head = node->next;
 821         else
 822                 node->prev->next = node->next;
 823
 824         if(node == chain->tail)
 825                 chain->tail = node->prev;
 826         else
 827                 node->next->prev = node->prev;
 828
 829         if(0 != chain->tail)
 830                 chain->tail->data->is_last = true;
 831
 832         chain->nodes--;
 833 }
 834
 835 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 836 {
 837         chain_remove_node_(chain, node);
 838         node_delete_(node);
 839 }
 840
 841 static unsigned chain_calculate_length_(FLAC__Metadata_Chain *chain)
 842 {
 843         const FLAC__Metadata_Node *node;
 844         unsigned length = 0;
 845         for(node = chain->head; node; node = node->next)
 846                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 847         return length;
 848 }
 849
 850 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 851 {
 852         FLAC__ASSERT(0 != node);
 853         FLAC__ASSERT(0 != node->data);
 854         FLAC__ASSERT(0 != iterator);
 855         FLAC__ASSERT(0 != iterator->current);
 856         FLAC__ASSERT(0 != iterator->chain);
 857         FLAC__ASSERT(0 != iterator->chain->head);
 858         FLAC__ASSERT(0 != iterator->chain->tail);
 859
 860         node->data->is_last = false;
 861
 862         node->prev = iterator->current->prev;
 863         node->next = iterator->current;
 864
 865         if(0 == node->prev)
 866                 iterator->chain->head = node;
 867         else
 868                 node->prev->next = node;
 869
 870         iterator->current->prev = node;
 871
 872         iterator->chain->nodes++;
 873 }
 874
 875 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 876 {
 877         FLAC__ASSERT(0 != node);
 878         FLAC__ASSERT(0 != node->data);
 879         FLAC__ASSERT(0 != iterator);
 880         FLAC__ASSERT(0 != iterator->current);
 881         FLAC__ASSERT(0 != iterator->chain);
 882         FLAC__ASSERT(0 != iterator->chain->head);
 883         FLAC__ASSERT(0 != iterator->chain->tail);
 884
 885         iterator->current->data->is_last = false;
 886
 887         node->prev = iterator->current;
 888         node->next = iterator->current->next;
 889
 890         if(0 == node->next)
 891                 iterator->chain->tail = node;
 892         else
 893                 node->next->prev = node;
 894
 895         node->prev->next = node;
 896
 897         iterator->chain->tail->data->is_last = true;
 898
 899         iterator->chain->nodes++;
 900 }
 901
 902 /* return true iff node and node->next are both padding */
 903 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 904 {
 905         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
 906                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
 907                 node->data->length += growth;
 908
 909                 chain_delete_node_(chain, node->next);
 910                 return true;
 911         }
 912         else
 913                 return false;
 914 }
 915
 916 static FLAC__bool chain_read_cb_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__IOCallback_Tell tell_cb, FLAC__IOCallback_Close close_cb)
 917 {
 918         FLAC__Metadata_Node *node;
 919
 920         FLAC__ASSERT(0 != chain);
 921
 922         /* we assume we're already at the beginning of the file */
 923
 924         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
 925                 case 0:
 926                         break;
 927                 case 1:
 928                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
 929                         return false;
 930                 case 2:
 931                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
 932                         return false;
 933                 case 3:
 934                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
 935                         return false;
 936                 default:
 937                         FLAC__ASSERT(0);
 938                         return false;
 939         }
 940
 941         {
 942                 FLAC__int64 pos = tell_cb(handle);
 943                 if(pos < 0) {
 944                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
 945                         return false;
 946                 }
 947                 chain->first_offset = (long)pos;
 948         }
 949
 950         {
 951                 FLAC__bool is_last;
 952                 FLAC__MetadataType type;
 953                 unsigned length;
 954
 955                 do {
 956                         node = node_new_();
 957                         if(0 == node) {
 958                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 959                                 return false;
 960                         }
 961
 962                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
 963                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
 964                                 return false;
 965                         }
 966
 967                         node->data = FLAC__metadata_object_new(type);
 968                         if(0 == node->data) {
 969                                 node_delete_(node);
 970                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 971                                 return false;
 972                         }
 973
 974                         node->data->is_last = is_last;
 975                         node->data->length = length;
 976
 977                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
 978                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
 979                                 node_delete_(node);
 980                                 return false;
 981                         }
 982                         chain_append_node_(chain, node);
 983                 } while(!is_last);
 984         }
 985
 986         {
 987                 FLAC__int64 pos = tell_cb(handle);
 988                 if(pos < 0) {
 989                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
 990                         return false;
 991                 }
 992                 chain->last_offset = (long)pos;
 993         }
 994
 995         close_cb(handle);
 996
 997         chain->initial_length = chain_calculate_length_(chain);
 998
 999         return true;
1000 }
1001
1002 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1003 {
1004         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1005
1006         if(0 != chain) {
1007                 chain->filename = 0;
1008                 chain->head = chain->tail = 0;
1009                 chain->nodes = 0;
1010                 chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1011                 chain->initial_length = 0;
1012         }
1013
1014         return chain;
1015 }
1016
1017 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1018 {
1019         FLAC__Metadata_Node *node, *next;
1020
1021         FLAC__ASSERT(0 != chain);
1022
1023         for(node = chain->head; node; ) {
1024                 next = node->next;
1025                 node_delete_(node);
1026                 node = next;
1027         }
1028
1029         if(0 != chain->filename)
1030                 free(chain->filename);
1031
1032         free(chain);
1033 }
1034
1035 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1036 {
1037         FLAC__Metadata_ChainStatus status;
1038
1039         FLAC__ASSERT(0 != chain);
1040
1041         status = chain->status;
1042         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1043         return status;
1044 }
1045
1046 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1047 {
1048         FILE *file;
1049
1050         FLAC__ASSERT(0 != chain);
1051         FLAC__ASSERT(0 != filename);
1052
1053         if(0 == (chain->filename = strdup(filename))) {
1054                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1055                 return false;
1056         }
1057
1058         if(0 == (file = fopen(filename, "rb"))) {
1059                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1060                 return false;
1061         }
1062
1063         if(!chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_, (FLAC__IOCallback_Close)fclose))
1064                 return false; /* chain->status is already set by chain_read_cb_ */
1065
1066         return true;
1067 }
1068
1069 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1070 {
1071         struct stat stats;
1072         const char *tempfile_path_prefix = 0;
1073         unsigned current_length;
1074
1075         FLAC__ASSERT(0 != chain);
1076
1077         current_length = chain_calculate_length_(chain);
1078
1079         if(use_padding) {
1080                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1081                         const unsigned delta = chain->initial_length - current_length;
1082                         chain->tail->data->length += delta;
1083                         current_length += delta;
1084                         FLAC__ASSERT(current_length == chain->initial_length);
1085                 }
1086                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1087                         FLAC__StreamMetadata *padding;
1088                         FLAC__Metadata_Node *node;
1089                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1090                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1091                                 return false;
1092                         }
1093                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1094                         if(0 == (node = node_new_())) {
1095                                 FLAC__metadata_object_delete(padding);
1096                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1097                                 return false;
1098                         }
1099                         node->data = padding;
1100                         chain_append_node_(chain, node);
1101                         current_length = chain_calculate_length_(chain);
1102                         FLAC__ASSERT(current_length == chain->initial_length);
1103                 }
1104                 else if(current_length > chain->initial_length) {
1105                         const unsigned delta = current_length - chain->initial_length;
1106                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1107                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1108                                         chain_delete_node_(chain, chain->tail);
1109                                         current_length = chain_calculate_length_(chain);
1110                                         FLAC__ASSERT(current_length == chain->initial_length);
1111                                 }
1112                                 else if(chain->tail->data->length >= delta) {
1113                                         chain->tail->data->length -= delta;
1114                                         current_length -= delta;
1115                                         FLAC__ASSERT(current_length == chain->initial_length);
1116                                 }
1117                         }
1118                 }
1119         }
1120
1121         if(preserve_file_stats)
1122                 get_file_stats_(chain->filename, &stats);
1123
1124         if(current_length == chain->initial_length) {
1125                 if(!chain_rewrite_chain_(chain))
1126                         return false;
1127         }
1128         else {
1129                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1130                         return false;
1131         }
1132
1133         if(preserve_file_stats)
1134                 set_file_stats_(chain->filename, &stats);
1135
1136         /* recompute lengths and offsets if necessary */
1137         if(chain->initial_length != current_length) {
1138                 const FLAC__Metadata_Node *node;
1139                 chain->initial_length = current_length;
1140                 chain->last_offset = chain->first_offset;
1141                 for(node = chain->head; node; node = node->next)
1142                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1143         }
1144
1145         return true;
1146 }
1147
1148 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1149 {
1150         FLAC__Metadata_Node *node;
1151
1152         FLAC__ASSERT(0 != chain);
1153
1154         for(node = chain->head; node; ) {
1155                 if(!chain_merge_adjacent_padding_(chain, node))
1156                         node = node->next;
1157         }
1158 }
1159
1160 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1161 {
1162         FLAC__Metadata_Node *node, *save;
1163         unsigned i;
1164
1165         FLAC__ASSERT(0 != chain);
1166
1167         /*
1168          * Don't try and be too smart... this simple algo is good enough for
1169          * the small number of nodes that we deal with.
1170          */
1171         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1172                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1173                         save = node->next;
1174                         chain_remove_node_(chain, node);
1175                         chain_append_node_(chain, node);
1176                         node = save;
1177                 }
1178                 else {
1179                         node = node->next;
1180                 }
1181         }
1182
1183         FLAC__metadata_chain_merge_padding(chain);
1184 }
1185
1186
1187 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1188 {
1189         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1190
1191         /* calloc() implies:
1192                 iterator->current = 0;
1193                 iterator->chain = 0;
1194         */
1195
1196         return iterator;
1197 }
1198
1199 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1200 {
1201         FLAC__ASSERT(0 != iterator);
1202
1203         free(iterator);
1204 }
1205
1206 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1207 {
1208         FLAC__ASSERT(0 != iterator);
1209         FLAC__ASSERT(0 != chain);
1210         FLAC__ASSERT(0 != chain->head);
1211
1212         iterator->chain = chain;
1213         iterator->current = chain->head;
1214 }
1215
1216 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1217 {
1218         FLAC__ASSERT(0 != iterator);
1219
1220         if(0 == iterator->current || 0 == iterator->current->next)
1221                 return false;
1222
1223         iterator->current = iterator->current->next;
1224         return true;
1225 }
1226
1227 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1228 {
1229         FLAC__ASSERT(0 != iterator);
1230
1231         if(0 == iterator->current || 0 == iterator->current->prev)
1232                 return false;
1233
1234         iterator->current = iterator->current->prev;
1235         return true;
1236 }
1237
1238 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1239 {
1240         FLAC__ASSERT(0 != iterator);
1241         FLAC__ASSERT(0 != iterator->current);
1242         FLAC__ASSERT(0 != iterator->current->data);
1243
1244         return iterator->current->data->type;
1245 }
1246
1247 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1248 {
1249         FLAC__ASSERT(0 != iterator);
1250         FLAC__ASSERT(0 != iterator->current);
1251
1252         return iterator->current->data;
1253 }
1254
1255 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1256 {
1257         FLAC__ASSERT(0 != iterator);
1258         FLAC__ASSERT(0 != block);
1259         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1260 }
1261
1262 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1263 {
1264         FLAC__Metadata_Node *save;
1265
1266         FLAC__ASSERT(0 != iterator);
1267         FLAC__ASSERT(0 != iterator->current);
1268
1269         if(0 == iterator->current->prev) {
1270                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1271                 return false;
1272         }
1273
1274         save = iterator->current->prev;
1275
1276         if(replace_with_padding) {
1277                 FLAC__metadata_object_delete_data(iterator->current->data);
1278                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1279         }
1280         else {
1281                 chain_delete_node_(iterator->chain, iterator->current);
1282         }
1283
1284         iterator->current = save;
1285         return true;
1286 }
1287
1288 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1289 {
1290         FLAC__Metadata_Node *node;
1291
1292         FLAC__ASSERT(0 != iterator);
1293         FLAC__ASSERT(0 != iterator->current);
1294         FLAC__ASSERT(0 != block);
1295
1296         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1297                 return false;
1298
1299         if(0 == iterator->current->prev) {
1300                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1301                 return false;
1302         }
1303
1304         if(0 == (node = node_new_()))
1305                 return false;
1306
1307         node->data = block;
1308         iterator_insert_node_(iterator, node);
1309         iterator->current = node;
1310         return true;
1311 }
1312
1313 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1314 {
1315         FLAC__Metadata_Node *node;
1316
1317         FLAC__ASSERT(0 != iterator);
1318         FLAC__ASSERT(0 != iterator->current);
1319         FLAC__ASSERT(0 != block);
1320
1321         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1322                 return false;
1323
1324         if(0 == (node = node_new_()))
1325                 return false;
1326
1327         node->data = block;
1328         iterator_insert_node_after_(iterator, node);
1329         iterator->current = node;
1330         return true;
1331 }
1332
1333
1334 /****************************************************************************
1335  *
1336  * Local function definitions
1337  *
1338  ***************************************************************************/
1339
1340 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1341 {
1342         unsigned i;
1343
1344         b += bytes;
1345
1346         for(i = 0; i < bytes; i++) {
1347                 *(--b) = (FLAC__byte)(val & 0xff);
1348                 val >>= 8;
1349         }
1350 }
1351
1352 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1353 {
1354         unsigned i;
1355
1356         for(i = 0; i < bytes; i++) {
1357                 *(b++) = (FLAC__byte)(val & 0xff);
1358                 val >>= 8;
1359         }
1360 }
1361
1362 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1363 {
1364         unsigned i;
1365
1366         b += bytes;
1367
1368         for(i = 0; i < bytes; i++) {
1369                 *(--b) = (FLAC__byte)(val & 0xff);
1370                 val >>= 8;
1371         }
1372 }
1373
1374 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1375 {
1376         FLAC__uint32 ret = 0;
1377         unsigned i;
1378
1379         for(i = 0; i < bytes; i++)
1380                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1381
1382         return ret;
1383 }
1384
1385 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1386 {
1387         FLAC__uint32 ret = 0;
1388         unsigned i;
1389
1390         b += bytes;
1391
1392         for(i = 0; i < bytes; i++)
1393                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1394
1395         return ret;
1396 }
1397
1398 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1399 {
1400         FLAC__uint64 ret = 0;
1401         unsigned i;
1402
1403         for(i = 0; i < bytes; i++)
1404                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1405
1406         return ret;
1407 }
1408
1409 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1410 {
1411         FLAC__ASSERT(0 != iterator);
1412         FLAC__ASSERT(0 != iterator->file);
1413
1414         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1415                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1416                 return false;
1417         }
1418
1419         return true;
1420 }
1421
1422 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1423 {
1424         FLAC__ASSERT(0 != iterator);
1425         FLAC__ASSERT(0 != iterator->file);
1426
1427         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
1428
1429         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1430 }
1431
1432 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
1433 {
1434         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1435
1436         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
1437                 return false;
1438
1439         *is_last = raw_header[0] & 0x80? true : false;
1440         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1441         *length = unpack_uint32_(raw_header + 1, 3);
1442
1443         /* Note that we don't check:
1444          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
1445          * we just will read in an opaque block
1446          */
1447
1448         return true;
1449 }
1450
1451 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
1452 {
1453         switch(block->type) {
1454                 case FLAC__METADATA_TYPE_STREAMINFO:
1455                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
1456                 case FLAC__METADATA_TYPE_PADDING:
1457                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
1458                 case FLAC__METADATA_TYPE_APPLICATION:
1459                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
1460                 case FLAC__METADATA_TYPE_SEEKTABLE:
1461                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
1462                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1463                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
1464                 case FLAC__METADATA_TYPE_CUESHEET:
1465                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
1466                 default:
1467                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
1468         }
1469 }
1470
1471 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
1472 {
1473         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1474
1475         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1476                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1477
1478         b = buffer;
1479
1480         /* we are using hardcoded numbers for simplicity but we should
1481          * probably eventually write a bit-level unpacker and use the
1482          * _STREAMINFO_ constants.
1483          */
1484         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1485         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1486         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1487         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1488         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1489         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1490         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1491         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1492         memcpy(block->md5sum, b+8, 16);
1493
1494         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1495 }
1496
1497
1498 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1499 {
1500         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1501
1502         if(0 != seek_cb(handle, block_length, SEEK_CUR))
1503                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1504
1505         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1506 }
1507
1508 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
1509 {
1510         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1511
1512         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
1513                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1514
1515         block_length -= id_bytes;
1516
1517         if(block_length == 0) {
1518                 block->data = 0;
1519         }
1520         else {
1521                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1522                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1523
1524                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1525                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1526         }
1527
1528         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1529 }
1530
1531 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1532 {
1533         unsigned i;
1534         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1535
1536         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1537
1538         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1539
1540         if(block->num_points == 0)
1541                 block->points = 0;
1542         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1543                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1544
1545         for(i = 0; i < block->num_points; i++) {
1546                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1547                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1548                 /* some MAGIC NUMBERs here */
1549                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1550                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1551                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1552         }
1553
1554         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1555 }
1556
1557 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
1558 {
1559         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1560         FLAC__byte buffer[4]; /* magic number is asserted below */
1561
1562         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == 4);
1563
1564         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
1565                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1566         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
1567
1568         if(0 != entry->entry)
1569                 free(entry->entry);
1570
1571         if(entry->length == 0) {
1572                 entry->entry = 0;
1573         }
1574         else {
1575                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length)))
1576                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1577
1578                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
1579                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1580         }
1581
1582         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1583 }
1584
1585 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
1586 {
1587         unsigned i;
1588         FLAC__Metadata_SimpleIteratorStatus status;
1589         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1590         FLAC__byte buffer[4]; /* magic number is asserted below */
1591
1592         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == 4);
1593
1594         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
1595                 return status;
1596
1597         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
1598                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1599         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
1600
1601         if(block->num_comments == 0) {
1602                 block->comments = 0;
1603         }
1604         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
1605                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1606
1607         for(i = 0; i < block->num_comments; i++) {
1608                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
1609                         return status;
1610         }
1611
1612         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1613 }
1614
1615 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
1616 {
1617         unsigned i, len;
1618         FLAC__byte buffer[32]; /* asserted below that this is big enough */
1619
1620         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
1621         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
1622         FLAC__ASSERT(sizeof(buffer) >= (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8);
1623
1624         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
1625         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
1626         if(read_cb(buffer, 1, len, handle) != len)
1627                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1628         track->offset = unpack_uint64_(buffer, len);
1629
1630         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
1631         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
1632         if(read_cb(buffer, 1, len, handle) != len)
1633                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1634         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
1635
1636         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
1637         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
1638         if(read_cb(track->isrc, 1, len, handle) != len)
1639                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1640
1641         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) % 8 == 0);
1642         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
1643         if(read_cb(buffer, 1, len, handle) != len)
1644                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1645         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
1646         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
1647         track->type = buffer[0] >> 7;
1648         track->pre_emphasis = (buffer[0] >> 6) & 1;
1649
1650         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
1651         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
1652         if(read_cb(buffer, 1, len, handle) != len)
1653                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1654         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
1655
1656         if(track->num_indices == 0) {
1657                 track->indices = 0;
1658         }
1659         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
1660                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1661
1662         for(i = 0; i < track->num_indices; i++) {
1663                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
1664                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
1665                 if(read_cb(buffer, 1, len, handle) != len)
1666                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1667                 track->indices[i].offset = unpack_uint64_(buffer, len);
1668
1669                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
1670                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
1671                 if(read_cb(buffer, 1, len, handle) != len)
1672                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1673                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
1674
1675                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
1676                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
1677                 if(read_cb(buffer, 1, len, handle) != len)
1678                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1679         }
1680
1681         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1682 }
1683
1684 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
1685 {
1686         unsigned i, len;
1687         FLAC__Metadata_SimpleIteratorStatus status;
1688         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
1689
1690         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
1691         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
1692
1693         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
1694         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
1695         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
1696                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1697
1698         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
1699         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
1700         if(read_cb(buffer, 1, len, handle) != len)
1701                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1702         block->lead_in = unpack_uint64_(buffer, len);
1703
1704         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
1705         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
1706         if(read_cb(buffer, 1, len, handle) != len)
1707                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1708         block->is_cd = buffer[0]&0x80? true : false;
1709
1710         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
1711         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
1712         if(read_cb(buffer, 1, len, handle) != len)
1713                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1714         block->num_tracks = unpack_uint32_(buffer, len);
1715
1716         if(block->num_tracks == 0) {
1717                 block->tracks = 0;
1718         }
1719         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
1720                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1721
1722         for(i = 0; i < block->num_tracks; i++) {
1723                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
1724                         return status;
1725         }
1726
1727         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1728 }
1729
1730 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
1731 {
1732         if(block_length == 0) {
1733                 block->data = 0;
1734         }
1735         else {
1736                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1737                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1738
1739                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1740                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1741         }
1742
1743         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1744 }
1745
1746 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
1747 {
1748         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
1749
1750         FLAC__ASSERT(0 != file);
1751         FLAC__ASSERT(0 != status);
1752         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
1753
1754         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
1755         pack_uint32_(block->length, buffer + 1, 3);
1756
1757         if(local__fwrite(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, file) != FLAC__STREAM_METADATA_HEADER_LENGTH) {
1758                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1759                 return false;
1760         }
1761
1762         return true;
1763 }
1764
1765 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
1766 {
1767         FLAC__ASSERT(0 != file);
1768         FLAC__ASSERT(0 != status);
1769
1770         switch(block->type) {
1771                 case FLAC__METADATA_TYPE_STREAMINFO:
1772                         *status = write_metadata_block_data_streaminfo_(file, &block->data.stream_info);
1773                         break;
1774                 case FLAC__METADATA_TYPE_PADDING:
1775                         *status = write_metadata_block_data_padding_(file, &block->data.padding, block->length);
1776                         break;
1777                 case FLAC__METADATA_TYPE_APPLICATION:
1778                         *status = write_metadata_block_data_application_(file, &block->data.application, block->length);
1779                         break;
1780                 case FLAC__METADATA_TYPE_SEEKTABLE:
1781                         *status = write_metadata_block_data_seektable_(file, &block->data.seek_table);
1782                         break;
1783                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1784                         *status = write_metadata_block_data_vorbis_comment_(file, &block->data.vorbis_comment);
1785                         break;
1786                 case FLAC__METADATA_TYPE_CUESHEET:
1787                         *status = write_metadata_block_data_cuesheet_(file, &block->data.cue_sheet);
1788                         break;
1789                 default:
1790                         *status = write_metadata_block_data_unknown_(file, &block->data.unknown, block->length);
1791                         break;
1792         }
1793         return (*status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1794 }
1795
1796 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_streaminfo_(FILE *file, const FLAC__StreamMetadata_StreamInfo *block)
1797 {
1798         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
1799         const unsigned channels1 = block->channels - 1;
1800         const unsigned bps1 = block->bits_per_sample - 1;
1801
1802         FLAC__ASSERT(0 != file);
1803
1804         /* we are using hardcoded numbers for simplicity but we should
1805          * probably eventually write a bit-level packer and use the
1806          * _STREAMINFO_ constants.
1807          */
1808         pack_uint32_(block->min_blocksize, buffer, 2);
1809         pack_uint32_(block->max_blocksize, buffer+2, 2);
1810         pack_uint32_(block->min_framesize, buffer+4, 3);
1811         pack_uint32_(block->max_framesize, buffer+7, 3);
1812         buffer[10] = (block->sample_rate >> 12) & 0xff;
1813         buffer[11] = (block->sample_rate >> 4) & 0xff;
1814         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
1815         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
1816         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
1817         memcpy(buffer+18, block->md5sum, 16);
1818
1819         if(local__fwrite(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, file) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1820                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1821
1822         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1823 }
1824
1825 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_padding_(FILE *file, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
1826 {
1827         unsigned i, n = block_length;
1828         FLAC__byte buffer[1024];
1829
1830         FLAC__ASSERT(0 != file);
1831
1832         (void)block;
1833
1834         memset(buffer, 0, 1024);
1835
1836         for(i = 0; i < n/1024; i++)
1837                 if(local__fwrite(buffer, 1, 1024, file) != 1024)
1838                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1839
1840         n %= 1024;
1841
1842         if(local__fwrite(buffer, 1, n, file) != n)
1843                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1844
1845         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1846 }
1847
1848 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_application_(FILE *file, const FLAC__StreamMetadata_Application *block, unsigned block_length)
1849 {
1850         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1851
1852         FLAC__ASSERT(0 != file);
1853
1854         if(local__fwrite(block->id, 1, id_bytes, file) != id_bytes)
1855                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1856
1857         block_length -= id_bytes;
1858
1859         if(local__fwrite(block->data, 1, block_length, file) != block_length)
1860                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1861
1862         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1863 }
1864
1865 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_seektable_(FILE *file, const FLAC__StreamMetadata_SeekTable *block)
1866 {
1867         unsigned i;
1868         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1869
1870         FLAC__ASSERT(0 != file);
1871
1872         for(i = 0; i < block->num_points; i++) {
1873                 /* some MAGIC NUMBERs here */
1874                 pack_uint64_(block->points[i].sample_number, buffer, 8);
1875                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
1876                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
1877                 if(local__fwrite(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, file) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1878                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1879         }
1880
1881         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1882 }
1883
1884 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_vorbis_comment_(FILE *file, const FLAC__StreamMetadata_VorbisComment *block)
1885 {
1886         unsigned i;
1887         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1888         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1889         FLAC__byte buffer[4]; /* magic number is asserted below */
1890
1891         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == 4);
1892         FLAC__ASSERT(0 != file);
1893
1894         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
1895         if(local__fwrite(buffer, 1, entry_length_len, file) != entry_length_len)
1896                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1897         if(local__fwrite(block->vendor_string.entry, 1, block->vendor_string.length, file) != block->vendor_string.length)
1898                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1899
1900         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
1901         if(local__fwrite(buffer, 1, num_comments_len, file) != num_comments_len)
1902                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1903
1904         for(i = 0; i < block->num_comments; i++) {
1905                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
1906                 if(local__fwrite(buffer, 1, entry_length_len, file) != entry_length_len)
1907                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1908                 if(local__fwrite(block->comments[i].entry, 1, block->comments[i].length, file) != block->comments[i].length)
1909                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1910         }
1911
1912         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1913 }
1914
1915 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_cuesheet_(FILE *file, const FLAC__StreamMetadata_CueSheet *block)
1916 {
1917         unsigned i, j, len;
1918         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
1919
1920         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
1921         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
1922         FLAC__ASSERT(sizeof(buffer) >= (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN)/8);
1923         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
1924
1925         FLAC__ASSERT(0 != file);
1926
1927         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
1928         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
1929         if(local__fwrite(block->media_catalog_number, 1, len, file) != len)
1930                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1931
1932         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
1933         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
1934         pack_uint64_(block->lead_in, buffer, len);
1935         if(local__fwrite(buffer, 1, len, file) != len)
1936                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1937
1938         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
1939         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
1940         memset(buffer, 0, len);
1941         if(block->is_cd)
1942                 buffer[0] |= 0x80;
1943         if(local__fwrite(buffer, 1, len, file) != len)
1944                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1945
1946         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
1947         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
1948         pack_uint32_(block->num_tracks, buffer, len);
1949         if(local__fwrite(buffer, 1, len, file) != len)
1950                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1951
1952         for(i = 0; i < block->num_tracks; i++) {
1953                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
1954
1955                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
1956                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
1957                 pack_uint64_(track->offset, buffer, len);
1958                 if(local__fwrite(buffer, 1, len, file) != len)
1959                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1960
1961                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
1962                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
1963                 pack_uint32_(track->number, buffer, len);
1964                 if(local__fwrite(buffer, 1, len, file) != len)
1965                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1966
1967                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
1968                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
1969                 if(local__fwrite(track->isrc, 1, len, file) != len)
1970                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1971
1972                 FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) % 8 == 0);
1973                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
1974                 memset(buffer, 0, len);
1975                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
1976                 if(local__fwrite(buffer, 1, len, file) != len)
1977                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1978
1979                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
1980                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
1981                 pack_uint32_(track->num_indices, buffer, len);
1982                 if(local__fwrite(buffer, 1, len, file) != len)
1983                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1984
1985                 for(j = 0; j < track->num_indices; j++) {
1986                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
1987
1988                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
1989                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
1990                         pack_uint64_(index->offset, buffer, len);
1991                         if(local__fwrite(buffer, 1, len, file) != len)
1992                                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1993
1994                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
1995                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
1996                         pack_uint32_(index->number, buffer, len);
1997                         if(local__fwrite(buffer, 1, len, file) != len)
1998                                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
1999
2000                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2001                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2002                         memset(buffer, 0, len);
2003                         if(local__fwrite(buffer, 1, len, file) != len)
2004                                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2005                 }
2006         }
2007
2008         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2009 }
2010
2011 FLAC__Metadata_SimpleIteratorStatus write_metadata_block_data_unknown_(FILE *file, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2012 {
2013         FLAC__ASSERT(0 != file);
2014
2015         if(local__fwrite(block->data, 1, block_length, file) != block_length)
2016                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2017
2018         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2019 }
2020
2021 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2022 {
2023         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2024                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2025                 return false;
2026         }
2027
2028         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2029                 return false;
2030
2031         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2032                 return false;
2033
2034         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2035                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2036                 return false;
2037         }
2038
2039         return read_metadata_block_header_(iterator);
2040 }
2041
2042 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2043 {
2044         FLAC__StreamMetadata *padding;
2045
2046         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2047                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2048                 return false;
2049         }
2050
2051         block->is_last = false;
2052
2053         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2054                 return false;
2055
2056         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2057                 return false;
2058
2059         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2060                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2061
2062         padding->is_last = padding_is_last;
2063         padding->length = padding_length;
2064
2065         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2066                 FLAC__metadata_object_delete(padding);
2067                 return false;
2068         }
2069
2070         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2071                 FLAC__metadata_object_delete(padding);
2072                 return false;
2073         }
2074
2075         FLAC__metadata_object_delete(padding);
2076
2077         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2078                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2079                 return false;
2080         }
2081
2082         return read_metadata_block_header_(iterator);
2083 }
2084
2085 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2086 {
2087         FILE *tempfile;
2088         char *tempfilename;
2089         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2090         long fixup_is_last_flag_offset = -1;
2091
2092         FLAC__ASSERT(0 != block || append == false);
2093
2094         if(iterator->is_last) {
2095                 if(append) {
2096                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2097                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2098                 }
2099                 else if(0 == block) {
2100                         simple_iterator_push_(iterator);
2101                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2102                                 (void)simple_iterator_pop_(iterator);
2103                                 return false;
2104                         }
2105                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2106                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2107                         if(!simple_iterator_pop_(iterator))
2108                                 return false;
2109                 }
2110         }
2111
2112         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2113                 return false;
2114
2115         if(0 != block) {
2116                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2117                         cleanup_tempfile_(&tempfile, &tempfilename);
2118                         return false;
2119                 }
2120
2121                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2122                         cleanup_tempfile_(&tempfile, &tempfilename);
2123                         return false;
2124                 }
2125         }
2126
2127         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2128                 return false;
2129
2130         if(append)
2131                 return FLAC__metadata_simple_iterator_next(iterator);
2132
2133         return true;
2134 }
2135
2136 FLAC__bool chain_rewrite_chain_(FLAC__Metadata_Chain *chain)
2137 {
2138         FILE *f;
2139         FLAC__Metadata_Node *node;
2140         FLAC__Metadata_SimpleIteratorStatus status;
2141
2142         FLAC__ASSERT(0 != chain);
2143         FLAC__ASSERT(0 != chain->filename);
2144         FLAC__ASSERT(0 != chain->head);
2145
2146         if(0 == (f = fopen(chain->filename, "r+b"))) {
2147                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2148                 return false;
2149         }
2150         if(0 != fseek(f, chain->first_offset, SEEK_SET)) {
2151                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2152                 return false;
2153         }
2154
2155         for(node = chain->head; node; node = node->next) {
2156                 if(!write_metadata_block_header_(f, &status, node->data)) {
2157                         chain->status = get_equivalent_status_(status);
2158                         return false;
2159                 }
2160                 if(!write_metadata_block_data_(f, &status, node->data)) {
2161                         chain->status = get_equivalent_status_(status);
2162                         return false;
2163                 }
2164         }
2165
2166         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
2167
2168         (void)fclose(f);
2169
2170         return true;
2171 }
2172
2173 FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
2174 {
2175         FILE *f, *tempfile;
2176         char *tempfilename;
2177         FLAC__Metadata_SimpleIteratorStatus status;
2178         const FLAC__Metadata_Node *node;
2179
2180         FLAC__ASSERT(0 != chain);
2181         FLAC__ASSERT(0 != chain->filename);
2182         FLAC__ASSERT(0 != chain->head);
2183
2184         /* copy the file prefix (data up to first metadata block */
2185         if(0 == (f = fopen(chain->filename, "rb"))) {
2186                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2187                 return false;
2188         }
2189         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
2190                 chain->status = get_equivalent_status_(status);
2191                 cleanup_tempfile_(&tempfile, &tempfilename);
2192                 return false;
2193         }
2194         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
2195                 chain->status = get_equivalent_status_(status);
2196                 cleanup_tempfile_(&tempfile, &tempfilename);
2197                 return false;
2198         }
2199
2200         /* write the metadata */
2201         for(node = chain->head; node; node = node->next) {
2202                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
2203                         chain->status = get_equivalent_status_(status);
2204                         return false;
2205                 }
2206                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
2207                         chain->status = get_equivalent_status_(status);
2208                         return false;
2209                 }
2210         }
2211         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
2212
2213         /* copy the file postfix (everything after the metadata) */
2214         if(0 != fseek(f, chain->last_offset, SEEK_SET)) {
2215                 cleanup_tempfile_(&tempfile, &tempfilename);
2216                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2217                 return false;
2218         }
2219         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
2220                 cleanup_tempfile_(&tempfile, &tempfilename);
2221                 chain->status = get_equivalent_status_(status);
2222                 return false;
2223         }
2224
2225         /* move the tempfile on top of the original */
2226         (void)fclose(f);
2227         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
2228                 return false;
2229
2230         return true;
2231 }
2232
2233 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2234 {
2235         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2236         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2237         iterator->depth++;
2238 }
2239
2240 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2241 {
2242         FLAC__ASSERT(iterator->depth > 0);
2243         iterator->depth--;
2244         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2245                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2246                 return false;
2247         }
2248
2249         return read_metadata_block_header_(iterator);
2250 }
2251
2252 /* return meanings:
2253  * 0: ok
2254  * 1: read error
2255  * 2: seek error
2256  * 3: not a FLAC file
2257  */
2258 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2259 {
2260         FLAC__byte buffer[4];
2261         size_t n;
2262         unsigned i;
2263
2264         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == 4);
2265
2266         /* skip any id3v2 tag */
2267         errno = 0;
2268         n = read_cb(buffer, 1, 4, handle);
2269         if(errno)
2270                 return 1;
2271         else if(n != 4)
2272                 return 3;
2273         else if(0 == memcmp(buffer, "ID3", 3)) {
2274                 unsigned tag_length = 0;
2275
2276                 /* skip to the tag length */
2277                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2278                         return 2;
2279
2280                 /* read the length */
2281                 for(i = 0; i < 4; i++) {
2282                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2283                                 return 1;
2284                         tag_length <<= 7;
2285                         tag_length |= (buffer[0] & 0x7f);
2286                 }
2287
2288                 /* skip the rest of the tag */
2289                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2290                         return 2;
2291
2292                 /* read the stream sync code */
2293                 errno = 0;
2294                 n = read_cb(buffer, 1, 4, handle);
2295                 if(errno)
2296                         return 1;
2297                 else if(n != 4)
2298                         return 3;
2299         }
2300
2301         /* check for the fLaC signature */
2302         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2303                 return 0;
2304         else
2305                 return 3;
2306 }
2307
2308 unsigned seek_to_first_metadata_block_(FILE *f)
2309 {
2310         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2311 }
2312
2313 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2314 {
2315         const long offset_end = append? iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length : iterator->offset[iterator->depth];
2316
2317         if(0 != fseek(iterator->file, 0, SEEK_SET)) {
2318                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2319                 return false;
2320         }
2321         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2322                 cleanup_tempfile_(tempfile, tempfilename);
2323                 return false;
2324         }
2325         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2326                 cleanup_tempfile_(tempfile, tempfilename);
2327                 return false;
2328         }
2329
2330         return true;
2331 }
2332
2333 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)
2334 {
2335         long save_offset = iterator->offset[iterator->depth]; /*@@@ 2G limit */
2336         FLAC__ASSERT(0 != *tempfile);
2337
2338         if(0 != fseek(iterator->file, save_offset + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length, SEEK_SET)) {
2339                 cleanup_tempfile_(tempfile, tempfilename);
2340                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2341                 return false;
2342         }
2343         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2344                 cleanup_tempfile_(tempfile, tempfilename);
2345                 return false;
2346         }
2347
2348         if(fixup_is_last_code != 0) {
2349                 /*
2350                  * if code == 1, it means a block was appended to the end so
2351                  *   we have to clear the is_last flag of the previous block
2352                  * if code == -1, it means the last block was deleted so
2353                  *   we have to set the is_last flag of the previous block
2354                  */
2355                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2356                 FLAC__byte x;
2357                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2358                         cleanup_tempfile_(tempfile, tempfilename);
2359                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2360                         return false;
2361                 }
2362                 if(fread(&x, 1, 1, *tempfile) != 1) {
2363                         cleanup_tempfile_(tempfile, tempfilename);
2364                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2365                         return false;
2366                 }
2367                 if(fixup_is_last_code > 0) {
2368                         FLAC__ASSERT(x & 0x80);
2369                         x &= 0x7f;
2370                 }
2371                 else {
2372                         FLAC__ASSERT(!(x & 0x80));
2373                         x |= 0x80;
2374                 }
2375                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2376                         cleanup_tempfile_(tempfile, tempfilename);
2377                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2378                         return false;
2379                 }
2380                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
2381                         cleanup_tempfile_(tempfile, tempfilename);
2382                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2383                         return false;
2384                 }
2385         }
2386
2387         (void)fclose(iterator->file);
2388
2389         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2390                 return false;
2391
2392         if(iterator->has_stats)
2393                 set_file_stats_(iterator->filename, &iterator->stats);
2394
2395         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
2396                 return false;
2397         if(backup) {
2398                 while(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length < save_offset)
2399                         if(!FLAC__metadata_simple_iterator_next(iterator))
2400                                 return false;
2401                 return true;
2402         }
2403         else {
2404                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2405                 FLAC__ASSERT(iterator->depth == 0);
2406                 iterator->offset[0] = save_offset;
2407                 iterator->depth++;
2408                 return simple_iterator_pop_(iterator);
2409         }
2410 }
2411
2412 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status)
2413 {
2414         FLAC__byte buffer[8192];
2415         unsigned n;
2416
2417         while(bytes > 0) {
2418                 n = min(sizeof(buffer), bytes);
2419                 if(fread(buffer, 1, n, file) != n) {
2420                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2421                         return false;
2422                 }
2423                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
2424                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2425                         return false;
2426                 }
2427                 bytes -= n;
2428         }
2429
2430         return true;
2431 }
2432
2433 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2434 {
2435         FLAC__byte buffer[8192];
2436         size_t n;
2437
2438         while(!feof(file)) {
2439                 n = fread(buffer, 1, sizeof(buffer), file);
2440                 if(n == 0 && !feof(file)) {
2441                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2442                         return false;
2443                 }
2444                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
2445                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2446                         return false;
2447                 }
2448         }
2449
2450         return true;
2451 }
2452
2453 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2454 {
2455         static const char *tempfile_suffix = ".metadata_edit";
2456         if(0 == tempfile_path_prefix) {
2457                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
2458                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2459                         return false;
2460                 }
2461                 strcpy(*tempfilename, filename);
2462                 strcat(*tempfilename, tempfile_suffix);
2463         }
2464         else {
2465                 const char *p = strrchr(filename, '/');
2466                 if(0 == p)
2467                         p = filename;
2468                 else
2469                         p++;
2470
2471                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
2472                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2473                         return false;
2474                 }
2475                 strcpy(*tempfilename, tempfile_path_prefix);
2476                 strcat(*tempfilename, "/");
2477                 strcat(*tempfilename, p);
2478                 strcat(*tempfilename, tempfile_suffix);
2479         }
2480
2481         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
2482                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
2483                 return false;
2484         }
2485
2486         return true;
2487 }
2488
2489 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2490 {
2491         FLAC__ASSERT(0 != filename);
2492         FLAC__ASSERT(0 != tempfile);
2493         FLAC__ASSERT(0 != *tempfile);
2494         FLAC__ASSERT(0 != tempfilename);
2495         FLAC__ASSERT(0 != *tempfilename);
2496         FLAC__ASSERT(0 != status);
2497
2498         (void)fclose(*tempfile);
2499         *tempfile = 0;
2500
2501 #if defined _MSC_VER || defined __MINGW32__
2502         if(unlink(filename) < 0) {
2503                 cleanup_tempfile_(tempfile, tempfilename);
2504                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
2505                 return false;
2506         }
2507 #endif
2508
2509         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
2510         if(0 != rename(*tempfilename, filename)) {
2511                 cleanup_tempfile_(tempfile, tempfilename);
2512                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
2513                 return false;
2514         }
2515
2516         cleanup_tempfile_(tempfile, tempfilename);
2517
2518         return true;
2519 }
2520
2521 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
2522 {
2523         if(0 != *tempfile) {
2524                 (void)fclose(*tempfile);
2525                 *tempfile = 0;
2526         }
2527
2528         if(0 != *tempfilename) {
2529                 (void)unlink(*tempfilename);
2530                 free(*tempfilename);
2531                 *tempfilename = 0;
2532         }
2533 }
2534
2535 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
2536 {
2537         FLAC__ASSERT(0 != filename);
2538         FLAC__ASSERT(0 != stats);
2539         return (0 == stat(filename, stats));
2540 }
2541
2542 void set_file_stats_(const char *filename, struct stat *stats)
2543 {
2544         struct utimbuf srctime;
2545
2546         FLAC__ASSERT(0 != filename);
2547         FLAC__ASSERT(0 != stats);
2548
2549         srctime.actime = stats->st_atime;
2550         srctime.modtime = stats->st_mtime;
2551         (void)chmod(filename, stats->st_mode);
2552         (void)utime(filename, &srctime);
2553 #if !defined _MSC_VER && !defined __MINGW32__
2554         (void)chown(filename, stats->st_uid, -1);
2555         (void)chown(filename, -1, stats->st_gid);
2556 #endif
2557 }
2558
2559 /* @@@ WATCHOUT @@@
2560  * We cast FLAC__int64 to long and use fseek()/ftell() because
2561  * none of our operations on metadata is ever likely to go past
2562  * 2 gigabytes.
2563  */
2564 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
2565 {
2566         FLAC__ASSERT(offset <= 0x7fffffff);
2567         return fseek((FILE*)handle, (long)offset, whence);
2568 }
2569
2570 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
2571 {
2572         return (long)ftell((FILE*)handle);
2573 }
2574
2575 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
2576 {
2577         switch(status) {
2578                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
2579                         return FLAC__METADATA_CHAIN_STATUS_OK;
2580                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
2581                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
2582                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
2583                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2584                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
2585                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
2586                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
2587                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
2588                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
2589                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
2590                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
2591                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
2592                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
2593                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2594                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
2595                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
2596                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
2597                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
2598                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
2599                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
2600                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
2601                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
2602                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
2603                 default:
2604                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
2605         }
2606 }