src/libFLAC/metadata_iterators.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2001,2002,2003,2004,2005  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__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
  92 static FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
  93 static FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block);
  94 static FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length);
  95 static FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length);
  96 static FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block);
  97 static FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block);
  98 static FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block);
  99 static FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length);
 100
 101 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
 102 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
 103 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
 104
 105 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
 106 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
 107
 108 static unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb);
 109 static unsigned seek_to_first_metadata_block_(FILE *f);
 110
 111 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
 112 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);
 113
 114 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status);
 115 static FLAC__bool copy_n_bytes_from_file_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOHandle temp_handle, FLAC__IOCallback_Write temp_write_cb, 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 static FLAC__bool copy_remaining_bytes_from_file_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Eof eof_cb, FLAC__IOHandle temp_handle, FLAC__IOCallback_Write temp_write_cb, FLAC__Metadata_SimpleIteratorStatus *status);
 118
 119 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 120 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 121 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
 122
 123 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats);
 124 static void set_file_stats_(const char *filename, struct stat *stats);
 125
 126 static int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence);
 127 static FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle);
 128
 129 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
 130
 131
 132 #ifdef FLAC__VALGRIND_TESTING
 133 static size_t local__fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
 134 {
 135         size_t ret = fwrite(ptr, size, nmemb, stream);
 136         if(!ferror(stream))
 137                 fflush(stream);
 138         return ret;
 139 }
 140 #else
 141 #define local__fwrite fwrite
 142 #endif
 143
 144 /****************************************************************************
 145  *
 146  * Level 0 implementation
 147  *
 148  ***************************************************************************/
 149
 150 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
 151 static void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
 152 static void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
 153
 154 typedef struct {
 155         FLAC__bool got_error;
 156         FLAC__StreamMetadata *object;
 157 } level0_client_data;
 158
 159 static FLAC__StreamMetadata *get_one_metadata_block_(const char *filename, FLAC__MetadataType type)
 160 {
 161         level0_client_data cd;
 162         FLAC__FileDecoder *decoder;
 163
 164         FLAC__ASSERT(0 != filename);
 165
 166         cd.got_error = false;
 167         cd.object = 0;
 168
 169         decoder = FLAC__file_decoder_new();
 170
 171         if(0 == decoder)
 172                 return 0;
 173
 174         FLAC__file_decoder_set_md5_checking(decoder, false);
 175         FLAC__file_decoder_set_filename(decoder, filename);
 176         FLAC__file_decoder_set_metadata_ignore_all(decoder);
 177         FLAC__file_decoder_set_metadata_respond(decoder, type);
 178         FLAC__file_decoder_set_write_callback(decoder, write_callback_);
 179         FLAC__file_decoder_set_metadata_callback(decoder, metadata_callback_);
 180         FLAC__file_decoder_set_error_callback(decoder, error_callback_);
 181         FLAC__file_decoder_set_client_data(decoder, &cd);
 182
 183         if(FLAC__file_decoder_init(decoder) != FLAC__FILE_DECODER_OK || cd.got_error) {
 184                 FLAC__file_decoder_finish(decoder);
 185                 FLAC__file_decoder_delete(decoder);
 186                 return 0;
 187         }
 188
 189         if(!FLAC__file_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
 190                 FLAC__file_decoder_finish(decoder);
 191                 FLAC__file_decoder_delete(decoder);
 192                 if(0 != cd.object)
 193                         FLAC__metadata_object_delete(cd.object);
 194                 return 0;
 195         }
 196
 197         FLAC__file_decoder_finish(decoder);
 198         FLAC__file_decoder_delete(decoder);
 199
 200         return cd.object;
 201 }
 202
 203 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 204 {
 205         FLAC__StreamMetadata *object;
 206
 207         FLAC__ASSERT(0 != filename);
 208         FLAC__ASSERT(0 != streaminfo);
 209
 210         object = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_STREAMINFO);
 211
 212         if (object) {
 213                 /* can just copy the contents since STREAMINFO has no internal structure */
 214                 *streaminfo = *object;
 215                 FLAC__metadata_object_delete(object);
 216                 return true;
 217         }
 218         else {
 219                 return false;
 220         }
 221 }
 222
 223 FLAC_API FLAC__bool FLAC__metadata_get_tags(const char *filename, FLAC__StreamMetadata **tags)
 224 {
 225         FLAC__ASSERT(0 != filename);
 226         FLAC__ASSERT(0 != tags);
 227
 228         *tags = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_VORBIS_COMMENT);
 229
 230         return 0 != *tags;
 231 }
 232
 233 FLAC_API FLAC__bool FLAC__metadata_get_cuesheet(const char *filename, FLAC__StreamMetadata **cuesheet)
 234 {
 235         FLAC__ASSERT(0 != filename);
 236         FLAC__ASSERT(0 != cuesheet);
 237
 238         *cuesheet = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_CUESHEET);
 239
 240         return 0 != *cuesheet;
 241 }
 242
 243 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 244 {
 245         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 246
 247         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 248 }
 249
 250 void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 251 {
 252         level0_client_data *cd = (level0_client_data *)client_data;
 253         (void)decoder;
 254
 255         /*
 256          * we assume we only get here when the one metadata block we were
 257          * looking for was passed to us
 258          */
 259         if(!cd->got_error && 0 == cd->object) {
 260                 if(0 == (cd->object = FLAC__metadata_object_clone(metadata)))
 261                         cd->got_error = true;
 262         }
 263 }
 264
 265 void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 266 {
 267         level0_client_data *cd = (level0_client_data *)client_data;
 268         (void)decoder;
 269
 270         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 271                 cd->got_error = true;
 272 }
 273
 274
 275 /****************************************************************************
 276  *
 277  * Level 1 implementation
 278  *
 279  ***************************************************************************/
 280
 281 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 282 /* 1 for initial offset, +4 for our own personal use */
 283
 284 struct FLAC__Metadata_SimpleIterator {
 285         FILE *file;
 286         char *filename, *tempfile_path_prefix;
 287         struct stat stats;
 288         FLAC__bool has_stats;
 289         FLAC__bool is_writable;
 290         FLAC__Metadata_SimpleIteratorStatus status;
 291         /*@@@ 2G limits here because of the offset type: */
 292         long offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 293         long first_offset; /* this is the offset to the STREAMINFO block */
 294         unsigned depth;
 295         /* this is the metadata block header of the current block we are pointing to: */
 296         FLAC__bool is_last;
 297         FLAC__MetadataType type;
 298         unsigned length;
 299 };
 300
 301 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 302         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 303         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 304         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 305         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 306         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 307         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 308         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 309         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 310         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 311         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 312         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 313         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 314         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 315 };
 316
 317
 318 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 319 {
 320         FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 321
 322         if(0 != iterator) {
 323                 iterator->file = 0;
 324                 iterator->filename = 0;
 325                 iterator->tempfile_path_prefix = 0;
 326                 iterator->has_stats = false;
 327                 iterator->is_writable = false;
 328                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 329                 iterator->first_offset = iterator->offset[0] = -1;
 330                 iterator->depth = 0;
 331         }
 332
 333         return iterator;
 334 }
 335
 336 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 337 {
 338         FLAC__ASSERT(0 != iterator);
 339
 340         if(0 != iterator->file) {
 341                 fclose(iterator->file);
 342                 iterator->file = 0;
 343                 if(iterator->has_stats)
 344                         set_file_stats_(iterator->filename, &iterator->stats);
 345         }
 346         if(0 != iterator->filename) {
 347                 free(iterator->filename);
 348                 iterator->filename = 0;
 349         }
 350         if(0 != iterator->tempfile_path_prefix) {
 351                 free(iterator->tempfile_path_prefix);
 352                 iterator->tempfile_path_prefix = 0;
 353         }
 354 }
 355
 356 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 357 {
 358         FLAC__ASSERT(0 != iterator);
 359
 360         simple_iterator_free_guts_(iterator);
 361         free(iterator);
 362 }
 363
 364 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 365 {
 366         FLAC__Metadata_SimpleIteratorStatus status;
 367
 368         FLAC__ASSERT(0 != iterator);
 369
 370         status = iterator->status;
 371         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 372         return status;
 373 }
 374
 375 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
 376 {
 377         unsigned ret;
 378
 379         FLAC__ASSERT(0 != iterator);
 380
 381         if(read_only || 0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 382                 iterator->is_writable = false;
 383                 if(read_only || errno == EACCES) {
 384                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 385                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 386                                 return false;
 387                         }
 388                 }
 389                 else {
 390                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 391                         return false;
 392                 }
 393         }
 394         else {
 395                 iterator->is_writable = true;
 396         }
 397
 398         ret = seek_to_first_metadata_block_(iterator->file);
 399         switch(ret) {
 400                 case 0:
 401                         iterator->depth = 0;
 402                         iterator->first_offset = iterator->offset[iterator->depth] = ftell(iterator->file);
 403                         return read_metadata_block_header_(iterator);
 404                 case 1:
 405                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 406                         return false;
 407                 case 2:
 408                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 409                         return false;
 410                 case 3:
 411                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 412                         return false;
 413                 default:
 414                         FLAC__ASSERT(0);
 415                         return false;
 416         }
 417 }
 418
 419 #if 0
 420 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 421 /*
 422  * The 'tempfile_path_prefix' allows you to specify a directory where
 423  * tempfiles should go.  Remember that if your metadata edits cause the
 424  * FLAC file to grow, the entire file will have to be rewritten.  If
 425  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 426  * same directory as the original FLAC file.  This makes replacing the
 427  * original with the tempfile fast but requires extra space in the same
 428  * partition for the tempfile.  If space is a problem, you can pass a
 429  * directory name belonging to a different partition in
 430  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 431  * '/' as the directory separator.  A trailing slash is not needed; it
 432  * will be added automatically.
 433  */
 434 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 435 #endif
 436
 437 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)
 438 {
 439         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 440
 441         FLAC__ASSERT(0 != iterator);
 442         FLAC__ASSERT(0 != filename);
 443
 444         simple_iterator_free_guts_(iterator);
 445
 446         if(!read_only && preserve_file_stats)
 447                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 448
 449         if(0 == (iterator->filename = strdup(filename))) {
 450                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 451                 return false;
 452         }
 453         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 454                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 455                 return false;
 456         }
 457
 458         return simple_iterator_prime_input_(iterator, read_only);
 459 }
 460
 461 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 462 {
 463         FLAC__ASSERT(0 != iterator);
 464         FLAC__ASSERT(0 != iterator->file);
 465
 466         return iterator->is_writable;
 467 }
 468
 469 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 470 {
 471         FLAC__ASSERT(0 != iterator);
 472         FLAC__ASSERT(0 != iterator->file);
 473
 474         if(iterator->is_last)
 475                 return false;
 476
 477         if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 478                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 479                 return false;
 480         }
 481
 482         iterator->offset[iterator->depth] = ftell(iterator->file);
 483
 484         return read_metadata_block_header_(iterator);
 485 }
 486
 487 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 488 {
 489         long this_offset;
 490
 491         FLAC__ASSERT(0 != iterator);
 492         FLAC__ASSERT(0 != iterator->file);
 493
 494         if(iterator->offset[iterator->depth] == iterator->first_offset)
 495                 return false;
 496
 497         if(0 != fseek(iterator->file, iterator->first_offset, SEEK_SET)) {
 498                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 499                 return false;
 500         }
 501         this_offset = iterator->first_offset;
 502         if(!read_metadata_block_header_(iterator))
 503                 return false;
 504
 505         /* we ignore any error from ftell() and catch it in fseek() */
 506         while(ftell(iterator->file) + (long)iterator->length < iterator->offset[iterator->depth]) {
 507                 if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 508                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 509                         return false;
 510                 }
 511                 this_offset = ftell(iterator->file);
 512                 if(!read_metadata_block_header_(iterator))
 513                         return false;
 514         }
 515
 516         iterator->offset[iterator->depth] = this_offset;
 517
 518         return true;
 519 }
 520
 521 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 522 {
 523         FLAC__ASSERT(0 != iterator);
 524         FLAC__ASSERT(0 != iterator->file);
 525
 526         return iterator->type;
 527 }
 528
 529 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 530 {
 531         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 532
 533         FLAC__ASSERT(0 != iterator);
 534         FLAC__ASSERT(0 != iterator->file);
 535
 536         if(0 != block) {
 537                 block->is_last = iterator->is_last;
 538                 block->length = iterator->length;
 539
 540                 if(!read_metadata_block_data_(iterator, block)) {
 541                         FLAC__metadata_object_delete(block);
 542                         return 0;
 543                 }
 544
 545                 /* back up to the beginning of the block data to stay consistent */
 546                 if(0 != fseek(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 547                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 548                         FLAC__metadata_object_delete(block);
 549                         return 0;
 550                 }
 551         }
 552         else
 553                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 554
 555         return block;
 556 }
 557
 558 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 559 {
 560         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 561         FLAC__bool ret;
 562
 563         FLAC__ASSERT(0 != iterator);
 564         FLAC__ASSERT(0 != iterator->file);
 565         FLAC__ASSERT(0 != block);
 566
 567         if(!iterator->is_writable) {
 568                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 569                 return false;
 570         }
 571
 572         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 573                 if(iterator->type != block->type) {
 574                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 575                         return false;
 576                 }
 577         }
 578
 579         block->is_last = iterator->is_last;
 580
 581         if(iterator->length == block->length)
 582                 return write_metadata_block_stationary_(iterator, block);
 583         else if(iterator->length > block->length) {
 584                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 585                         ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 586                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 587                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 588                         return ret;
 589                 }
 590                 else {
 591                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 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         }
 597         else /* iterator->length < block->length */ {
 598                 unsigned padding_leftover = 0;
 599                 FLAC__bool padding_is_last = false;
 600                 if(use_padding) {
 601                         /* first see if we can even use padding */
 602                         if(iterator->is_last) {
 603                                 use_padding = false;
 604                         }
 605                         else {
 606                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 607                                 simple_iterator_push_(iterator);
 608                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 609                                         (void)simple_iterator_pop_(iterator);
 610                                         return false;
 611                                 }
 612                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 613                                         use_padding = false;
 614                                 }
 615                                 else {
 616                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 617                                                 padding_leftover = 0;
 618                                                 block->is_last = iterator->is_last;
 619                                         }
 620                                         else if(iterator->length < extra_padding_bytes_required)
 621                                                 use_padding = false;
 622                                         else {
 623                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 624                                                 padding_is_last = iterator->is_last;
 625                                                 block->is_last = false;
 626                                         }
 627                                 }
 628                                 if(!simple_iterator_pop_(iterator))
 629                                         return false;
 630                         }
 631                 }
 632                 if(use_padding) {
 633                         if(padding_leftover == 0) {
 634                                 ret = write_metadata_block_stationary_(iterator, block);
 635                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 636                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 637                                 return ret;
 638                         }
 639                         else {
 640                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 641                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 642                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 643                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 644                                 return ret;
 645                         }
 646                 }
 647                 else {
 648                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 649                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 650                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 651                         return ret;
 652                 }
 653         }
 654 }
 655
 656 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 657 {
 658         unsigned padding_leftover = 0;
 659         FLAC__bool padding_is_last = false;
 660
 661         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 662         FLAC__bool ret;
 663
 664         FLAC__ASSERT(0 != iterator);
 665         FLAC__ASSERT(0 != iterator->file);
 666         FLAC__ASSERT(0 != block);
 667
 668         if(!iterator->is_writable)
 669                 return false;
 670
 671         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 672                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 673                 return false;
 674         }
 675
 676         block->is_last = iterator->is_last;
 677
 678         if(use_padding) {
 679                 /* first see if we can even use padding */
 680                 if(iterator->is_last) {
 681                         use_padding = false;
 682                 }
 683                 else {
 684                         simple_iterator_push_(iterator);
 685                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 686                                 (void)simple_iterator_pop_(iterator);
 687                                 return false;
 688                         }
 689                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 690                                 use_padding = false;
 691                         }
 692                         else {
 693                                 if(iterator->length == block->length) {
 694                                         padding_leftover = 0;
 695                                         block->is_last = iterator->is_last;
 696                                 }
 697                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 698                                         use_padding = false;
 699                                 else {
 700                                         padding_leftover = iterator->length - block->length;
 701                                         padding_is_last = iterator->is_last;
 702                                         block->is_last = false;
 703                                 }
 704                         }
 705                         if(!simple_iterator_pop_(iterator))
 706                                 return false;
 707                 }
 708         }
 709         if(use_padding) {
 710                 /* move to the next block, which is suitable padding */
 711                 if(!FLAC__metadata_simple_iterator_next(iterator))
 712                         return false;
 713                 if(padding_leftover == 0) {
 714                         ret = write_metadata_block_stationary_(iterator, block);
 715                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 716                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 717                         return ret;
 718                 }
 719                 else {
 720                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 721                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 722                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 723                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 724                         return ret;
 725                 }
 726         }
 727         else {
 728                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 729                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 730                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 731                 return ret;
 732         }
 733 }
 734
 735 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 736 {
 737         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 738         FLAC__bool ret;
 739
 740         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 741                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 742                 return false;
 743         }
 744
 745         if(use_padding) {
 746                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 747                 if(0 == padding) {
 748                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 749                         return false;
 750                 }
 751                 padding->length = iterator->length;
 752                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 753                         FLAC__metadata_object_delete(padding);
 754                         return false;
 755                 }
 756                 FLAC__metadata_object_delete(padding);
 757                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 758                         return false;
 759                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 760                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 761                 return true;
 762         }
 763         else {
 764                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 765                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 766                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 767                 return ret;
 768         }
 769 }
 770
 771
 772
 773 /****************************************************************************
 774  *
 775  * Level 2 implementation
 776  *
 777  ***************************************************************************/
 778
 779
 780 typedef struct FLAC__Metadata_Node {
 781         FLAC__StreamMetadata *data;
 782         struct FLAC__Metadata_Node *prev, *next;
 783 } FLAC__Metadata_Node;
 784
 785 struct FLAC__Metadata_Chain {
 786         char *filename; /* will be NULL if using callbacks */
 787         FLAC__Metadata_Node *head;
 788         FLAC__Metadata_Node *tail;
 789         unsigned nodes;
 790         FLAC__Metadata_ChainStatus status;
 791         long first_offset, last_offset; /*@@@ 2G limit */
 792         /*
 793          * This is the length of the chain initially read from the FLAC file.
 794          * it is used to compare against the current length to decide whether
 795          * or not the whole file has to be rewritten.
 796          */
 797         unsigned initial_length; /*@@@ 4G limit */
 798 };
 799
 800 struct FLAC__Metadata_Iterator {
 801         FLAC__Metadata_Chain *chain;
 802         FLAC__Metadata_Node *current;
 803 };
 804
 805 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 806         "FLAC__METADATA_CHAIN_STATUS_OK",
 807         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 808         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 809         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 810         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 811         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 812         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 813         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 814         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 815         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 816         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 817         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 818         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
 819         "FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
 820         "FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
 821         "FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
 822 };
 823
 824
 825 static FLAC__Metadata_Node *node_new_()
 826 {
 827         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 828 }
 829
 830 static void node_delete_(FLAC__Metadata_Node *node)
 831 {
 832         FLAC__ASSERT(0 != node);
 833         if(0 != node->data)
 834                 FLAC__metadata_object_delete(node->data);
 835         free(node);
 836 }
 837
 838 static void chain_init_(FLAC__Metadata_Chain *chain)
 839 {
 840         FLAC__ASSERT(0 != chain);
 841
 842         chain->filename = 0;
 843         chain->head = chain->tail = 0;
 844         chain->nodes = 0;
 845         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 846         chain->initial_length = 0;
 847 }
 848
 849 static void chain_clear_(FLAC__Metadata_Chain *chain)
 850 {
 851         FLAC__Metadata_Node *node, *next;
 852
 853         FLAC__ASSERT(0 != chain);
 854
 855         for(node = chain->head; node; ) {
 856                 next = node->next;
 857                 node_delete_(node);
 858                 node = next;
 859         }
 860
 861         if(0 != chain->filename)
 862                 free(chain->filename);
 863
 864         chain_init_(chain);
 865 }
 866
 867 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 868 {
 869         FLAC__ASSERT(0 != chain);
 870         FLAC__ASSERT(0 != node);
 871         FLAC__ASSERT(0 != node->data);
 872
 873         node->next = node->prev = 0;
 874         node->data->is_last = true;
 875         if(0 != chain->tail)
 876                 chain->tail->data->is_last = false;
 877
 878         if(0 == chain->head)
 879                 chain->head = node;
 880         else {
 881                 FLAC__ASSERT(0 != chain->tail);
 882                 chain->tail->next = node;
 883                 node->prev = chain->tail;
 884         }
 885         chain->tail = node;
 886         chain->nodes++;
 887 }
 888
 889 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 890 {
 891         FLAC__ASSERT(0 != chain);
 892         FLAC__ASSERT(0 != node);
 893
 894         if(node == chain->head)
 895                 chain->head = node->next;
 896         else
 897                 node->prev->next = node->next;
 898
 899         if(node == chain->tail)
 900                 chain->tail = node->prev;
 901         else
 902                 node->next->prev = node->prev;
 903
 904         if(0 != chain->tail)
 905                 chain->tail->data->is_last = true;
 906
 907         chain->nodes--;
 908 }
 909
 910 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 911 {
 912         chain_remove_node_(chain, node);
 913         node_delete_(node);
 914 }
 915
 916 static unsigned chain_calculate_length_(FLAC__Metadata_Chain *chain)
 917 {
 918         const FLAC__Metadata_Node *node;
 919         unsigned length = 0;
 920         for(node = chain->head; node; node = node->next)
 921                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 922         return length;
 923 }
 924
 925 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 926 {
 927         FLAC__ASSERT(0 != node);
 928         FLAC__ASSERT(0 != node->data);
 929         FLAC__ASSERT(0 != iterator);
 930         FLAC__ASSERT(0 != iterator->current);
 931         FLAC__ASSERT(0 != iterator->chain);
 932         FLAC__ASSERT(0 != iterator->chain->head);
 933         FLAC__ASSERT(0 != iterator->chain->tail);
 934
 935         node->data->is_last = false;
 936
 937         node->prev = iterator->current->prev;
 938         node->next = iterator->current;
 939
 940         if(0 == node->prev)
 941                 iterator->chain->head = node;
 942         else
 943                 node->prev->next = node;
 944
 945         iterator->current->prev = node;
 946
 947         iterator->chain->nodes++;
 948 }
 949
 950 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 951 {
 952         FLAC__ASSERT(0 != node);
 953         FLAC__ASSERT(0 != node->data);
 954         FLAC__ASSERT(0 != iterator);
 955         FLAC__ASSERT(0 != iterator->current);
 956         FLAC__ASSERT(0 != iterator->chain);
 957         FLAC__ASSERT(0 != iterator->chain->head);
 958         FLAC__ASSERT(0 != iterator->chain->tail);
 959
 960         iterator->current->data->is_last = false;
 961
 962         node->prev = iterator->current;
 963         node->next = iterator->current->next;
 964
 965         if(0 == node->next)
 966                 iterator->chain->tail = node;
 967         else
 968                 node->next->prev = node;
 969
 970         node->prev->next = node;
 971
 972         iterator->chain->tail->data->is_last = true;
 973
 974         iterator->chain->nodes++;
 975 }
 976
 977 /* return true iff node and node->next are both padding */
 978 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 979 {
 980         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
 981                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
 982                 node->data->length += growth;
 983
 984                 chain_delete_node_(chain, node->next);
 985                 return true;
 986         }
 987         else
 988                 return false;
 989 }
 990
 991 /* Returns the new length of the chain, or 0 if there was an error. */
 992 /* WATCHOUT: This can get called multiple times before a write, so
 993  * it should still work when this happens.
 994  */
 995 /* WATCHOUT: Make sure to also update the logic in
 996  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
 997  */
 998 static unsigned chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
 999 {
1000         unsigned current_length = chain_calculate_length_(chain);
1001
1002         if(use_padding) {
1003                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1004                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1005                         const unsigned delta = chain->initial_length - current_length;
1006                         chain->tail->data->length += delta;
1007                         current_length += delta;
1008                         FLAC__ASSERT(current_length == chain->initial_length);
1009                 }
1010                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1011                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1012                         FLAC__StreamMetadata *padding;
1013                         FLAC__Metadata_Node *node;
1014                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1015                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1016                                 return 0;
1017                         }
1018                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1019                         if(0 == (node = node_new_())) {
1020                                 FLAC__metadata_object_delete(padding);
1021                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1022                                 return 0;
1023                         }
1024                         node->data = padding;
1025                         chain_append_node_(chain, node);
1026                         current_length = chain_calculate_length_(chain);
1027                         FLAC__ASSERT(current_length == chain->initial_length);
1028                 }
1029                 /* if the metadata grew but the last block is padding, try cutting the padding to restore the original length so we don't have to rewrite the whole file */
1030                 else if(current_length > chain->initial_length) {
1031                         const unsigned delta = current_length - chain->initial_length;
1032                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1033                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1034                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1035                                         chain_delete_node_(chain, chain->tail);
1036                                         current_length = chain_calculate_length_(chain);
1037                                         FLAC__ASSERT(current_length == chain->initial_length);
1038                                 }
1039                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1040                                 else if(chain->tail->data->length >= delta) {
1041                                         chain->tail->data->length -= delta;
1042                                         current_length -= delta;
1043                                         FLAC__ASSERT(current_length == chain->initial_length);
1044                                 }
1045                         }
1046                 }
1047         }
1048
1049         return current_length;
1050 }
1051
1052 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)
1053 {
1054         FLAC__Metadata_Node *node;
1055
1056         FLAC__ASSERT(0 != chain);
1057
1058         /* we assume we're already at the beginning of the file */
1059
1060         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
1061                 case 0:
1062                         break;
1063                 case 1:
1064                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1065                         return false;
1066                 case 2:
1067                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1068                         return false;
1069                 case 3:
1070                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
1071                         return false;
1072                 default:
1073                         FLAC__ASSERT(0);
1074                         return false;
1075         }
1076
1077         {
1078                 FLAC__int64 pos = tell_cb(handle);
1079                 if(pos < 0) {
1080                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1081                         return false;
1082                 }
1083                 chain->first_offset = (long)pos;
1084         }
1085
1086         {
1087                 FLAC__bool is_last;
1088                 FLAC__MetadataType type;
1089                 unsigned length;
1090
1091                 do {
1092                         node = node_new_();
1093                         if(0 == node) {
1094                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1095                                 return false;
1096                         }
1097
1098                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
1099                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1100                                 return false;
1101                         }
1102
1103                         node->data = FLAC__metadata_object_new(type);
1104                         if(0 == node->data) {
1105                                 node_delete_(node);
1106                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1107                                 return false;
1108                         }
1109
1110                         node->data->is_last = is_last;
1111                         node->data->length = length;
1112
1113                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
1114                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1115                                 node_delete_(node);
1116                                 return false;
1117                         }
1118                         chain_append_node_(chain, node);
1119                 } while(!is_last);
1120         }
1121
1122         {
1123                 FLAC__int64 pos = tell_cb(handle);
1124                 if(pos < 0) {
1125                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1126                         return false;
1127                 }
1128                 chain->last_offset = (long)pos;
1129         }
1130
1131         chain->initial_length = chain_calculate_length_(chain);
1132
1133         return true;
1134 }
1135
1136 static FLAC__bool chain_rewrite_metadata_in_place_cb_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, FLAC__IOCallback_Seek seek_cb)
1137 {
1138         FLAC__Metadata_Node *node;
1139
1140         FLAC__ASSERT(0 != chain);
1141         FLAC__ASSERT(0 != chain->head);
1142
1143         if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
1144                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1145                 return false;
1146         }
1147
1148         for(node = chain->head; node; node = node->next) {
1149                 if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
1150                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1151                         return false;
1152                 }
1153                 if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
1154                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1155                         return false;
1156                 }
1157         }
1158
1159         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1160
1161         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1162         return true;
1163 }
1164
1165 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
1166 {
1167         FILE *file;
1168         FLAC__bool ret;
1169
1170         FLAC__ASSERT(0 != chain->filename);
1171
1172         if(0 == (file = fopen(chain->filename, "r+b"))) {
1173                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1174                 return false;
1175         }
1176
1177         /* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
1178         ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
1179
1180         fclose(file);
1181
1182         return ret;
1183 }
1184
1185 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1186 {
1187         FILE *f, *tempfile;
1188         char *tempfilename;
1189         FLAC__Metadata_SimpleIteratorStatus status;
1190         const FLAC__Metadata_Node *node;
1191
1192         FLAC__ASSERT(0 != chain);
1193         FLAC__ASSERT(0 != chain->filename);
1194         FLAC__ASSERT(0 != chain->head);
1195
1196         /* copy the file prefix (data up to first metadata block */
1197         if(0 == (f = fopen(chain->filename, "rb"))) {
1198                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1199                 return false;
1200         }
1201         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1202                 chain->status = get_equivalent_status_(status);
1203                 cleanup_tempfile_(&tempfile, &tempfilename);
1204                 return false;
1205         }
1206         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1207                 chain->status = get_equivalent_status_(status);
1208                 cleanup_tempfile_(&tempfile, &tempfilename);
1209                 return false;
1210         }
1211
1212         /* write the metadata */
1213         for(node = chain->head; node; node = node->next) {
1214                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1215                         chain->status = get_equivalent_status_(status);
1216                         return false;
1217                 }
1218                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1219                         chain->status = get_equivalent_status_(status);
1220                         return false;
1221                 }
1222         }
1223         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1224
1225         /* copy the file postfix (everything after the metadata) */
1226         if(0 != fseek(f, chain->last_offset, SEEK_SET)) {
1227                 cleanup_tempfile_(&tempfile, &tempfilename);
1228                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1229                 return false;
1230         }
1231         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1232                 cleanup_tempfile_(&tempfile, &tempfilename);
1233                 chain->status = get_equivalent_status_(status);
1234                 return false;
1235         }
1236
1237         /* move the tempfile on top of the original */
1238         (void)fclose(f);
1239         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1240                 return false;
1241
1242         return true;
1243 }
1244
1245 /* assumes 'handle' is already at beginning of file */
1246 static FLAC__bool chain_rewrite_file_cb_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__IOCallback_Eof eof_cb, FLAC__IOHandle temp_handle, FLAC__IOCallback_Write temp_write_cb)
1247 {
1248         FLAC__Metadata_SimpleIteratorStatus status;
1249         const FLAC__Metadata_Node *node;
1250
1251         FLAC__ASSERT(0 != chain);
1252         FLAC__ASSERT(0 == chain->filename);
1253         FLAC__ASSERT(0 != chain->head);
1254
1255         /* copy the file prefix (data up to first metadata block */
1256         if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
1257                 chain->status = get_equivalent_status_(status);
1258                 return false;
1259         }
1260
1261         /* write the metadata */
1262         for(node = chain->head; node; node = node->next) {
1263                 if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
1264                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1265                         return false;
1266                 }
1267                 if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
1268                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1269                         return false;
1270                 }
1271         }
1272         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1273
1274         /* copy the file postfix (everything after the metadata) */
1275         if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
1276                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1277                 return false;
1278         }
1279         if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
1280                 chain->status = get_equivalent_status_(status);
1281                 return false;
1282         }
1283
1284         return true;
1285 }
1286
1287 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1288 {
1289         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1290
1291         if(0 != chain)
1292                 chain_init_(chain);
1293
1294         return chain;
1295 }
1296
1297 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1298 {
1299         FLAC__ASSERT(0 != chain);
1300
1301         chain_clear_(chain);
1302
1303         free(chain);
1304 }
1305
1306 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1307 {
1308         FLAC__Metadata_ChainStatus status;
1309
1310         FLAC__ASSERT(0 != chain);
1311
1312         status = chain->status;
1313         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1314         return status;
1315 }
1316
1317 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1318 {
1319         FILE *file;
1320         FLAC__bool ret;
1321
1322         FLAC__ASSERT(0 != chain);
1323         FLAC__ASSERT(0 != filename);
1324
1325         chain_clear_(chain);
1326
1327         if(0 == (chain->filename = strdup(filename))) {
1328                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1329                 return false;
1330         }
1331
1332         if(0 == (file = fopen(filename, "rb"))) {
1333                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1334                 return false;
1335         }
1336
1337         /* chain_read_cb_() sets chain->status for us */
1338         ret = chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_);
1339
1340         fclose(file);
1341
1342         return ret;
1343 }
1344
1345 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1346 {
1347         FLAC__ASSERT(0 != chain);
1348
1349         chain_clear_(chain);
1350
1351         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
1352                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1353                 return false;
1354         }
1355
1356         /* rewind */
1357         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1358                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1359                 return false;
1360         }
1361
1362         if(!chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell))
1363                 return false; /* chain->status is already set by chain_read_cb_ */
1364
1365         return true;
1366 }
1367
1368 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1369 {
1370         /* This does all the same checks that are in chain_prepare_for_write_()
1371          * but doesn't actually alter the chain.  Make sure to update the logic
1372          * here if chain_prepare_for_write_() changes.
1373          */
1374         const unsigned current_length = chain_calculate_length_(chain);
1375
1376         FLAC__ASSERT(0 != chain);
1377
1378         if(use_padding) {
1379                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1380                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING)
1381                         return false;
1382                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1383                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length)
1384                         return false;
1385                 /* if the metadata grew but the last block is padding, try cutting the padding to restore the original length so we don't have to rewrite the whole file */
1386                 else if(current_length > chain->initial_length) {
1387                         const unsigned delta = current_length - chain->initial_length;
1388                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1389                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1390                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta)
1391                                         return false;
1392                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1393                                 else if(chain->tail->data->length >= delta)
1394                                         return false;
1395                         }
1396                 }
1397         }
1398
1399         return (current_length != chain->initial_length);
1400 }
1401
1402 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1403 {
1404         struct stat stats;
1405         const char *tempfile_path_prefix = 0;
1406         unsigned current_length;
1407
1408         FLAC__ASSERT(0 != chain);
1409
1410         if (0 == chain->filename) {
1411                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1412                 return false;
1413         }
1414
1415         current_length = chain_prepare_for_write_(chain, use_padding);
1416
1417         /* a return value of 0 means there was an error; chain->status is already set */
1418         if (0 == current_length)
1419                 return false;
1420
1421         if(preserve_file_stats)
1422                 get_file_stats_(chain->filename, &stats);
1423
1424         if(current_length == chain->initial_length) {
1425                 if(!chain_rewrite_metadata_in_place_(chain))
1426                         return false;
1427         }
1428         else {
1429                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1430                         return false;
1431
1432                 /* recompute lengths and offsets */
1433                 {
1434                         const FLAC__Metadata_Node *node;
1435                         chain->initial_length = current_length;
1436                         chain->last_offset = chain->first_offset;
1437                         for(node = chain->head; node; node = node->next)
1438                                 chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1439                 }
1440         }
1441
1442         if(preserve_file_stats)
1443                 set_file_stats_(chain->filename, &stats);
1444
1445         return true;
1446 }
1447
1448 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1449 {
1450         unsigned current_length;
1451
1452         FLAC__ASSERT(0 != chain);
1453
1454         if (0 != chain->filename) {
1455                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1456                 return false;
1457         }
1458
1459         if (0 == callbacks.write || 0 == callbacks.seek) {
1460                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1461                 return false;
1462         }
1463
1464         if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1465                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1466                 return false;
1467         }
1468
1469         current_length = chain_prepare_for_write_(chain, use_padding);
1470
1471         /* a return value of 0 means there was an error; chain->status is already set */
1472         if (0 == current_length)
1473                 return false;
1474
1475         FLAC__ASSERT(current_length == chain->initial_length);
1476
1477         return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
1478 }
1479
1480 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks_and_tempfile(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks, FLAC__IOHandle temp_handle, FLAC__IOCallbacks temp_callbacks)
1481 {
1482         unsigned current_length;
1483
1484         FLAC__ASSERT(0 != chain);
1485
1486         if (0 != chain->filename) {
1487                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1488                 return false;
1489         }
1490
1491         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
1492                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1493                 return false;
1494         }
1495         if (0 == temp_callbacks.write) {
1496                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1497                 return false;
1498         }
1499
1500         if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1501                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1502                 return false;
1503         }
1504
1505         current_length = chain_prepare_for_write_(chain, use_padding);
1506
1507         /* a return value of 0 means there was an error; chain->status is already set */
1508         if (0 == current_length)
1509                 return false;
1510
1511         FLAC__ASSERT(current_length != chain->initial_length);
1512
1513         /* rewind */
1514         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1515                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1516                 return false;
1517         }
1518
1519         if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
1520                 return false;
1521
1522         /* recompute lengths and offsets */
1523         {
1524                 const FLAC__Metadata_Node *node;
1525                 chain->initial_length = current_length;
1526                 chain->last_offset = chain->first_offset;
1527                 for(node = chain->head; node; node = node->next)
1528                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1529         }
1530
1531         return true;
1532 }
1533
1534 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1535 {
1536         FLAC__Metadata_Node *node;
1537
1538         FLAC__ASSERT(0 != chain);
1539
1540         for(node = chain->head; node; ) {
1541                 if(!chain_merge_adjacent_padding_(chain, node))
1542                         node = node->next;
1543         }
1544 }
1545
1546 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1547 {
1548         FLAC__Metadata_Node *node, *save;
1549         unsigned i;
1550
1551         FLAC__ASSERT(0 != chain);
1552
1553         /*
1554          * Don't try and be too smart... this simple algo is good enough for
1555          * the small number of nodes that we deal with.
1556          */
1557         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1558                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1559                         save = node->next;
1560                         chain_remove_node_(chain, node);
1561                         chain_append_node_(chain, node);
1562                         node = save;
1563                 }
1564                 else {
1565                         node = node->next;
1566                 }
1567         }
1568
1569         FLAC__metadata_chain_merge_padding(chain);
1570 }
1571
1572
1573 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1574 {
1575         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1576
1577         /* calloc() implies:
1578                 iterator->current = 0;
1579                 iterator->chain = 0;
1580         */
1581
1582         return iterator;
1583 }
1584
1585 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1586 {
1587         FLAC__ASSERT(0 != iterator);
1588
1589         free(iterator);
1590 }
1591
1592 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1593 {
1594         FLAC__ASSERT(0 != iterator);
1595         FLAC__ASSERT(0 != chain);
1596         FLAC__ASSERT(0 != chain->head);
1597
1598         iterator->chain = chain;
1599         iterator->current = chain->head;
1600 }
1601
1602 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1603 {
1604         FLAC__ASSERT(0 != iterator);
1605
1606         if(0 == iterator->current || 0 == iterator->current->next)
1607                 return false;
1608
1609         iterator->current = iterator->current->next;
1610         return true;
1611 }
1612
1613 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1614 {
1615         FLAC__ASSERT(0 != iterator);
1616
1617         if(0 == iterator->current || 0 == iterator->current->prev)
1618                 return false;
1619
1620         iterator->current = iterator->current->prev;
1621         return true;
1622 }
1623
1624 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1625 {
1626         FLAC__ASSERT(0 != iterator);
1627         FLAC__ASSERT(0 != iterator->current);
1628         FLAC__ASSERT(0 != iterator->current->data);
1629
1630         return iterator->current->data->type;
1631 }
1632
1633 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1634 {
1635         FLAC__ASSERT(0 != iterator);
1636         FLAC__ASSERT(0 != iterator->current);
1637
1638         return iterator->current->data;
1639 }
1640
1641 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1642 {
1643         FLAC__ASSERT(0 != iterator);
1644         FLAC__ASSERT(0 != block);
1645         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1646 }
1647
1648 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1649 {
1650         FLAC__Metadata_Node *save;
1651
1652         FLAC__ASSERT(0 != iterator);
1653         FLAC__ASSERT(0 != iterator->current);
1654
1655         if(0 == iterator->current->prev) {
1656                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1657                 return false;
1658         }
1659
1660         save = iterator->current->prev;
1661
1662         if(replace_with_padding) {
1663                 FLAC__metadata_object_delete_data(iterator->current->data);
1664                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1665         }
1666         else {
1667                 chain_delete_node_(iterator->chain, iterator->current);
1668         }
1669
1670         iterator->current = save;
1671         return true;
1672 }
1673
1674 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1675 {
1676         FLAC__Metadata_Node *node;
1677
1678         FLAC__ASSERT(0 != iterator);
1679         FLAC__ASSERT(0 != iterator->current);
1680         FLAC__ASSERT(0 != block);
1681
1682         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1683                 return false;
1684
1685         if(0 == iterator->current->prev) {
1686                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1687                 return false;
1688         }
1689
1690         if(0 == (node = node_new_()))
1691                 return false;
1692
1693         node->data = block;
1694         iterator_insert_node_(iterator, node);
1695         iterator->current = node;
1696         return true;
1697 }
1698
1699 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1700 {
1701         FLAC__Metadata_Node *node;
1702
1703         FLAC__ASSERT(0 != iterator);
1704         FLAC__ASSERT(0 != iterator->current);
1705         FLAC__ASSERT(0 != block);
1706
1707         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1708                 return false;
1709
1710         if(0 == (node = node_new_()))
1711                 return false;
1712
1713         node->data = block;
1714         iterator_insert_node_after_(iterator, node);
1715         iterator->current = node;
1716         return true;
1717 }
1718
1719
1720 /****************************************************************************
1721  *
1722  * Local function definitions
1723  *
1724  ***************************************************************************/
1725
1726 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1727 {
1728         unsigned i;
1729
1730         b += bytes;
1731
1732         for(i = 0; i < bytes; i++) {
1733                 *(--b) = (FLAC__byte)(val & 0xff);
1734                 val >>= 8;
1735         }
1736 }
1737
1738 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1739 {
1740         unsigned i;
1741
1742         for(i = 0; i < bytes; i++) {
1743                 *(b++) = (FLAC__byte)(val & 0xff);
1744                 val >>= 8;
1745         }
1746 }
1747
1748 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1749 {
1750         unsigned i;
1751
1752         b += bytes;
1753
1754         for(i = 0; i < bytes; i++) {
1755                 *(--b) = (FLAC__byte)(val & 0xff);
1756                 val >>= 8;
1757         }
1758 }
1759
1760 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1761 {
1762         FLAC__uint32 ret = 0;
1763         unsigned i;
1764
1765         for(i = 0; i < bytes; i++)
1766                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1767
1768         return ret;
1769 }
1770
1771 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1772 {
1773         FLAC__uint32 ret = 0;
1774         unsigned i;
1775
1776         b += bytes;
1777
1778         for(i = 0; i < bytes; i++)
1779                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1780
1781         return ret;
1782 }
1783
1784 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1785 {
1786         FLAC__uint64 ret = 0;
1787         unsigned i;
1788
1789         for(i = 0; i < bytes; i++)
1790                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1791
1792         return ret;
1793 }
1794
1795 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1796 {
1797         FLAC__ASSERT(0 != iterator);
1798         FLAC__ASSERT(0 != iterator->file);
1799
1800         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1801                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1802                 return false;
1803         }
1804
1805         return true;
1806 }
1807
1808 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1809 {
1810         FLAC__ASSERT(0 != iterator);
1811         FLAC__ASSERT(0 != iterator->file);
1812
1813         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
1814
1815         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1816 }
1817
1818 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
1819 {
1820         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1821
1822         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
1823                 return false;
1824
1825         *is_last = raw_header[0] & 0x80? true : false;
1826         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1827         *length = unpack_uint32_(raw_header + 1, 3);
1828
1829         /* Note that we don't check:
1830          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
1831          * we just will read in an opaque block
1832          */
1833
1834         return true;
1835 }
1836
1837 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
1838 {
1839         switch(block->type) {
1840                 case FLAC__METADATA_TYPE_STREAMINFO:
1841                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
1842                 case FLAC__METADATA_TYPE_PADDING:
1843                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
1844                 case FLAC__METADATA_TYPE_APPLICATION:
1845                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
1846                 case FLAC__METADATA_TYPE_SEEKTABLE:
1847                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
1848                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1849                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
1850                 case FLAC__METADATA_TYPE_CUESHEET:
1851                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
1852                 default:
1853                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
1854         }
1855 }
1856
1857 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
1858 {
1859         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1860
1861         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1862                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1863
1864         b = buffer;
1865
1866         /* we are using hardcoded numbers for simplicity but we should
1867          * probably eventually write a bit-level unpacker and use the
1868          * _STREAMINFO_ constants.
1869          */
1870         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1871         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1872         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1873         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1874         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1875         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1876         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1877         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1878         memcpy(block->md5sum, b+8, 16);
1879
1880         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1881 }
1882
1883
1884 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1885 {
1886         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1887
1888         if(0 != seek_cb(handle, block_length, SEEK_CUR))
1889                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1890
1891         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1892 }
1893
1894 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
1895 {
1896         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1897
1898         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
1899                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1900
1901         block_length -= id_bytes;
1902
1903         if(block_length == 0) {
1904                 block->data = 0;
1905         }
1906         else {
1907                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1908                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1909
1910                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1911                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1912         }
1913
1914         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1915 }
1916
1917 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1918 {
1919         unsigned i;
1920         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1921
1922         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1923
1924         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1925
1926         if(block->num_points == 0)
1927                 block->points = 0;
1928         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1929                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1930
1931         for(i = 0; i < block->num_points; i++) {
1932                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1933                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1934                 /* some MAGIC NUMBERs here */
1935                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1936                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1937                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1938         }
1939
1940         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1941 }
1942
1943 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
1944 {
1945         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1946         FLAC__byte buffer[4]; /* magic number is asserted below */
1947
1948         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == 4);
1949
1950         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
1951                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1952         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
1953
1954         if(0 != entry->entry)
1955                 free(entry->entry);
1956
1957         if(entry->length == 0) {
1958                 entry->entry = 0;
1959         }
1960         else {
1961                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length+1)))
1962                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1963
1964                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
1965                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1966
1967                 entry->entry[entry->length] = '\0';
1968         }
1969
1970         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1971 }
1972
1973 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
1974 {
1975         unsigned i;
1976         FLAC__Metadata_SimpleIteratorStatus status;
1977         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1978         FLAC__byte buffer[4]; /* magic number is asserted below */
1979
1980         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == 4);
1981
1982         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
1983                 return status;
1984
1985         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
1986                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1987         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
1988
1989         if(block->num_comments == 0) {
1990                 block->comments = 0;
1991         }
1992         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
1993                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1994
1995         for(i = 0; i < block->num_comments; i++) {
1996                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
1997                         return status;
1998         }
1999
2000         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2001 }
2002
2003 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
2004 {
2005         unsigned i, len;
2006         FLAC__byte buffer[32]; /* asserted below that this is big enough */
2007
2008         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2009         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2010         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);
2011
2012         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2013         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2014         if(read_cb(buffer, 1, len, handle) != len)
2015                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2016         track->offset = unpack_uint64_(buffer, len);
2017
2018         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2019         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2020         if(read_cb(buffer, 1, len, handle) != len)
2021                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2022         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
2023
2024         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2025         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2026         if(read_cb(track->isrc, 1, len, handle) != len)
2027                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2028
2029         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);
2030         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2031         if(read_cb(buffer, 1, len, handle) != len)
2032                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2033         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
2034         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
2035         track->type = buffer[0] >> 7;
2036         track->pre_emphasis = (buffer[0] >> 6) & 1;
2037
2038         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2039         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2040         if(read_cb(buffer, 1, len, handle) != len)
2041                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2042         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
2043
2044         if(track->num_indices == 0) {
2045                 track->indices = 0;
2046         }
2047         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
2048                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2049
2050         for(i = 0; i < track->num_indices; i++) {
2051                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2052                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2053                 if(read_cb(buffer, 1, len, handle) != len)
2054                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2055                 track->indices[i].offset = unpack_uint64_(buffer, len);
2056
2057                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2058                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2059                 if(read_cb(buffer, 1, len, handle) != len)
2060                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2061                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
2062
2063                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2064                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2065                 if(read_cb(buffer, 1, len, handle) != len)
2066                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2067         }
2068
2069         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2070 }
2071
2072 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
2073 {
2074         unsigned i, len;
2075         FLAC__Metadata_SimpleIteratorStatus status;
2076         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
2077
2078         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
2079         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
2080
2081         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2082         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2083         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
2084                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2085
2086         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2087         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2088         if(read_cb(buffer, 1, len, handle) != len)
2089                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2090         block->lead_in = unpack_uint64_(buffer, len);
2091
2092         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2093         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2094         if(read_cb(buffer, 1, len, handle) != len)
2095                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2096         block->is_cd = buffer[0]&0x80? true : false;
2097
2098         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2099         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2100         if(read_cb(buffer, 1, len, handle) != len)
2101                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2102         block->num_tracks = unpack_uint32_(buffer, len);
2103
2104         if(block->num_tracks == 0) {
2105                 block->tracks = 0;
2106         }
2107         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
2108                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2109
2110         for(i = 0; i < block->num_tracks; i++) {
2111                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
2112                         return status;
2113         }
2114
2115         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2116 }
2117
2118 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2119 {
2120         if(block_length == 0) {
2121                 block->data = 0;
2122         }
2123         else {
2124                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2125                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2126
2127                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2128                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2129         }
2130
2131         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2132 }
2133
2134 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2135 {
2136         FLAC__ASSERT(0 != file);
2137         FLAC__ASSERT(0 != status);
2138
2139         if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2140                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2141                 return false;
2142         }
2143
2144         return true;
2145 }
2146
2147 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2148 {
2149         FLAC__ASSERT(0 != file);
2150         FLAC__ASSERT(0 != status);
2151
2152         if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2153                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2154                 return true;
2155         }
2156         else {
2157                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2158                 return false;
2159         }
2160 }
2161
2162 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2163 {
2164         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
2165
2166         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
2167
2168         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
2169         pack_uint32_(block->length, buffer + 1, 3);
2170
2171         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2172                 return false;
2173
2174         return true;
2175 }
2176
2177 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2178 {
2179         FLAC__ASSERT(0 != block);
2180
2181         switch(block->type) {
2182                 case FLAC__METADATA_TYPE_STREAMINFO:
2183                         return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
2184                 case FLAC__METADATA_TYPE_PADDING:
2185                         return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
2186                 case FLAC__METADATA_TYPE_APPLICATION:
2187                         return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
2188                 case FLAC__METADATA_TYPE_SEEKTABLE:
2189                         return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
2190                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2191                         return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
2192                 case FLAC__METADATA_TYPE_CUESHEET:
2193                         return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
2194                 default:
2195                         return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
2196         }
2197 }
2198
2199 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
2200 {
2201         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
2202         const unsigned channels1 = block->channels - 1;
2203         const unsigned bps1 = block->bits_per_sample - 1;
2204
2205         /* we are using hardcoded numbers for simplicity but we should
2206          * probably eventually write a bit-level packer and use the
2207          * _STREAMINFO_ constants.
2208          */
2209         pack_uint32_(block->min_blocksize, buffer, 2);
2210         pack_uint32_(block->max_blocksize, buffer+2, 2);
2211         pack_uint32_(block->min_framesize, buffer+4, 3);
2212         pack_uint32_(block->max_framesize, buffer+7, 3);
2213         buffer[10] = (block->sample_rate >> 12) & 0xff;
2214         buffer[11] = (block->sample_rate >> 4) & 0xff;
2215         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
2216         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
2217         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
2218         memcpy(buffer+18, block->md5sum, 16);
2219
2220         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2221                 return false;
2222
2223         return true;
2224 }
2225
2226 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
2227 {
2228         unsigned i, n = block_length;
2229         FLAC__byte buffer[1024];
2230
2231         (void)block;
2232
2233         memset(buffer, 0, 1024);
2234
2235         for(i = 0; i < n/1024; i++)
2236                 if(write_cb(buffer, 1, 1024, handle) != 1024)
2237                         return false;
2238
2239         n %= 1024;
2240
2241         if(write_cb(buffer, 1, n, handle) != n)
2242                 return false;
2243
2244         return true;
2245 }
2246
2247 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
2248 {
2249         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2250
2251         if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
2252                 return false;
2253
2254         block_length -= id_bytes;
2255
2256         if(write_cb(block->data, 1, block_length, handle) != block_length)
2257                 return false;
2258
2259         return true;
2260 }
2261
2262 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
2263 {
2264         unsigned i;
2265         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2266
2267         for(i = 0; i < block->num_points; i++) {
2268                 /* some MAGIC NUMBERs here */
2269                 pack_uint64_(block->points[i].sample_number, buffer, 8);
2270                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
2271                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
2272                 if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2273                         return false;
2274         }
2275
2276         return true;
2277 }
2278
2279 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
2280 {
2281         unsigned i;
2282         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2283         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2284         FLAC__byte buffer[4]; /* magic number is asserted below */
2285
2286         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == 4);
2287
2288         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
2289         if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2290                 return false;
2291         if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
2292                 return false;
2293
2294         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
2295         if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2296                 return false;
2297
2298         for(i = 0; i < block->num_comments; i++) {
2299                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
2300                 if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2301                         return false;
2302                 if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
2303                         return false;
2304         }
2305
2306         return true;
2307 }
2308
2309 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
2310 {
2311         unsigned i, j, len;
2312         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
2313
2314         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2315         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
2316         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);
2317         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2318
2319         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2320         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2321         if(write_cb(block->media_catalog_number, 1, len, handle) != len)
2322                 return false;
2323
2324         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2325         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2326         pack_uint64_(block->lead_in, buffer, len);
2327         if(write_cb(buffer, 1, len, handle) != len)
2328                 return false;
2329
2330         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2331         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2332         memset(buffer, 0, len);
2333         if(block->is_cd)
2334                 buffer[0] |= 0x80;
2335         if(write_cb(buffer, 1, len, handle) != len)
2336                 return false;
2337
2338         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2339         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2340         pack_uint32_(block->num_tracks, buffer, len);
2341         if(write_cb(buffer, 1, len, handle) != len)
2342                 return false;
2343
2344         for(i = 0; i < block->num_tracks; i++) {
2345                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
2346
2347                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2348                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2349                 pack_uint64_(track->offset, buffer, len);
2350                 if(write_cb(buffer, 1, len, handle) != len)
2351                         return false;
2352
2353                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2354                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2355                 pack_uint32_(track->number, buffer, len);
2356                 if(write_cb(buffer, 1, len, handle) != len)
2357                         return false;
2358
2359                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2360                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2361                 if(write_cb(track->isrc, 1, len, handle) != len)
2362                         return false;
2363
2364                 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);
2365                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2366                 memset(buffer, 0, len);
2367                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
2368                 if(write_cb(buffer, 1, len, handle) != len)
2369                         return false;
2370
2371                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2372                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2373                 pack_uint32_(track->num_indices, buffer, len);
2374                 if(write_cb(buffer, 1, len, handle) != len)
2375                         return false;
2376
2377                 for(j = 0; j < track->num_indices; j++) {
2378                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
2379
2380                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2381                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2382                         pack_uint64_(index->offset, buffer, len);
2383                         if(write_cb(buffer, 1, len, handle) != len)
2384                                 return false;
2385
2386                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2387                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2388                         pack_uint32_(index->number, buffer, len);
2389                         if(write_cb(buffer, 1, len, handle) != len)
2390                                 return false;
2391
2392                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2393                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2394                         memset(buffer, 0, len);
2395                         if(write_cb(buffer, 1, len, handle) != len)
2396                                 return false;
2397                 }
2398         }
2399
2400         return true;
2401 }
2402
2403 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2404 {
2405         if(write_cb(block->data, 1, block_length, handle) != block_length)
2406                 return false;
2407
2408         return true;
2409 }
2410
2411 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2412 {
2413         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2414                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2415                 return false;
2416         }
2417
2418         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2419                 return false;
2420
2421         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2422                 return false;
2423
2424         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2425                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2426                 return false;
2427         }
2428
2429         return read_metadata_block_header_(iterator);
2430 }
2431
2432 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2433 {
2434         FLAC__StreamMetadata *padding;
2435
2436         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2437                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2438                 return false;
2439         }
2440
2441         block->is_last = false;
2442
2443         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2444                 return false;
2445
2446         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2447                 return false;
2448
2449         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2450                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2451
2452         padding->is_last = padding_is_last;
2453         padding->length = padding_length;
2454
2455         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2456                 FLAC__metadata_object_delete(padding);
2457                 return false;
2458         }
2459
2460         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2461                 FLAC__metadata_object_delete(padding);
2462                 return false;
2463         }
2464
2465         FLAC__metadata_object_delete(padding);
2466
2467         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2468                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2469                 return false;
2470         }
2471
2472         return read_metadata_block_header_(iterator);
2473 }
2474
2475 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2476 {
2477         FILE *tempfile;
2478         char *tempfilename;
2479         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2480         long fixup_is_last_flag_offset = -1;
2481
2482         FLAC__ASSERT(0 != block || append == false);
2483
2484         if(iterator->is_last) {
2485                 if(append) {
2486                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2487                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2488                 }
2489                 else if(0 == block) {
2490                         simple_iterator_push_(iterator);
2491                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2492                                 (void)simple_iterator_pop_(iterator);
2493                                 return false;
2494                         }
2495                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2496                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2497                         if(!simple_iterator_pop_(iterator))
2498                                 return false;
2499                 }
2500         }
2501
2502         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2503                 return false;
2504
2505         if(0 != block) {
2506                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2507                         cleanup_tempfile_(&tempfile, &tempfilename);
2508                         return false;
2509                 }
2510
2511                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2512                         cleanup_tempfile_(&tempfile, &tempfilename);
2513                         return false;
2514                 }
2515         }
2516
2517         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2518                 return false;
2519
2520         if(append)
2521                 return FLAC__metadata_simple_iterator_next(iterator);
2522
2523         return true;
2524 }
2525
2526 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2527 {
2528         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2529         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2530         iterator->depth++;
2531 }
2532
2533 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2534 {
2535         FLAC__ASSERT(iterator->depth > 0);
2536         iterator->depth--;
2537         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2538                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2539                 return false;
2540         }
2541
2542         return read_metadata_block_header_(iterator);
2543 }
2544
2545 /* return meanings:
2546  * 0: ok
2547  * 1: read error
2548  * 2: seek error
2549  * 3: not a FLAC file
2550  */
2551 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2552 {
2553         FLAC__byte buffer[4];
2554         size_t n;
2555         unsigned i;
2556
2557         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == 4);
2558
2559         /* skip any id3v2 tag */
2560         errno = 0;
2561         n = read_cb(buffer, 1, 4, handle);
2562         if(errno)
2563                 return 1;
2564         else if(n != 4)
2565                 return 3;
2566         else if(0 == memcmp(buffer, "ID3", 3)) {
2567                 unsigned tag_length = 0;
2568
2569                 /* skip to the tag length */
2570                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2571                         return 2;
2572
2573                 /* read the length */
2574                 for(i = 0; i < 4; i++) {
2575                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2576                                 return 1;
2577                         tag_length <<= 7;
2578                         tag_length |= (buffer[0] & 0x7f);
2579                 }
2580
2581                 /* skip the rest of the tag */
2582                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2583                         return 2;
2584
2585                 /* read the stream sync code */
2586                 errno = 0;
2587                 n = read_cb(buffer, 1, 4, handle);
2588                 if(errno)
2589                         return 1;
2590                 else if(n != 4)
2591                         return 3;
2592         }
2593
2594         /* check for the fLaC signature */
2595         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2596                 return 0;
2597         else
2598                 return 3;
2599 }
2600
2601 unsigned seek_to_first_metadata_block_(FILE *f)
2602 {
2603         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2604 }
2605
2606 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2607 {
2608         const long offset_end = append? iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length : iterator->offset[iterator->depth];
2609
2610         if(0 != fseek(iterator->file, 0, SEEK_SET)) {
2611                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2612                 return false;
2613         }
2614         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2615                 cleanup_tempfile_(tempfile, tempfilename);
2616                 return false;
2617         }
2618         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2619                 cleanup_tempfile_(tempfile, tempfilename);
2620                 return false;
2621         }
2622
2623         return true;
2624 }
2625
2626 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)
2627 {
2628         long save_offset = iterator->offset[iterator->depth]; /*@@@ 2G limit */
2629         FLAC__ASSERT(0 != *tempfile);
2630
2631         if(0 != fseek(iterator->file, save_offset + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length, SEEK_SET)) {
2632                 cleanup_tempfile_(tempfile, tempfilename);
2633                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2634                 return false;
2635         }
2636         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2637                 cleanup_tempfile_(tempfile, tempfilename);
2638                 return false;
2639         }
2640
2641         if(fixup_is_last_code != 0) {
2642                 /*
2643                  * if code == 1, it means a block was appended to the end so
2644                  *   we have to clear the is_last flag of the previous block
2645                  * if code == -1, it means the last block was deleted so
2646                  *   we have to set the is_last flag of the previous block
2647                  */
2648                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2649                 FLAC__byte x;
2650                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2651                         cleanup_tempfile_(tempfile, tempfilename);
2652                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2653                         return false;
2654                 }
2655                 if(fread(&x, 1, 1, *tempfile) != 1) {
2656                         cleanup_tempfile_(tempfile, tempfilename);
2657                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2658                         return false;
2659                 }
2660                 if(fixup_is_last_code > 0) {
2661                         FLAC__ASSERT(x & 0x80);
2662                         x &= 0x7f;
2663                 }
2664                 else {
2665                         FLAC__ASSERT(!(x & 0x80));
2666                         x |= 0x80;
2667                 }
2668                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2669                         cleanup_tempfile_(tempfile, tempfilename);
2670                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2671                         return false;
2672                 }
2673                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
2674                         cleanup_tempfile_(tempfile, tempfilename);
2675                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2676                         return false;
2677                 }
2678         }
2679
2680         (void)fclose(iterator->file);
2681
2682         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2683                 return false;
2684
2685         if(iterator->has_stats)
2686                 set_file_stats_(iterator->filename, &iterator->stats);
2687
2688         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
2689                 return false;
2690         if(backup) {
2691                 while(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length < save_offset)
2692                         if(!FLAC__metadata_simple_iterator_next(iterator))
2693                                 return false;
2694                 return true;
2695         }
2696         else {
2697                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2698                 FLAC__ASSERT(iterator->depth == 0);
2699                 iterator->offset[0] = save_offset;
2700                 iterator->depth++;
2701                 return simple_iterator_pop_(iterator);
2702         }
2703 }
2704
2705 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status)
2706 {
2707         FLAC__byte buffer[8192];
2708         unsigned n;
2709
2710         while(bytes > 0) {
2711                 n = min(sizeof(buffer), bytes);
2712                 if(fread(buffer, 1, n, file) != n) {
2713                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2714                         return false;
2715                 }
2716                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
2717                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2718                         return false;
2719                 }
2720                 bytes -= n;
2721         }
2722
2723         return true;
2724 }
2725
2726 FLAC__bool copy_n_bytes_from_file_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOHandle temp_handle, FLAC__IOCallback_Write temp_write_cb, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status)
2727 {
2728         FLAC__byte buffer[8192];
2729         unsigned n;
2730
2731         while(bytes > 0) {
2732                 n = min(sizeof(buffer), bytes);
2733                 if(read_cb(buffer, 1, n, handle) != n) {
2734                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2735                         return false;
2736                 }
2737                 if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
2738                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2739                         return false;
2740                 }
2741                 bytes -= n;
2742         }
2743
2744         return true;
2745 }
2746
2747 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2748 {
2749         FLAC__byte buffer[8192];
2750         size_t n;
2751
2752         while(!feof(file)) {
2753                 n = fread(buffer, 1, sizeof(buffer), file);
2754                 if(n == 0 && !feof(file)) {
2755                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2756                         return false;
2757                 }
2758                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
2759                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2760                         return false;
2761                 }
2762         }
2763
2764         return true;
2765 }
2766
2767 FLAC__bool copy_remaining_bytes_from_file_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Eof eof_cb, FLAC__IOHandle temp_handle, FLAC__IOCallback_Write temp_write_cb, FLAC__Metadata_SimpleIteratorStatus *status)
2768 {
2769         FLAC__byte buffer[8192];
2770         size_t n;
2771
2772         while(!eof_cb(handle)) {
2773                 n = read_cb(buffer, 1, sizeof(buffer), handle);
2774                 if(n == 0 && !eof_cb(handle)) {
2775                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2776                         return false;
2777                 }
2778                 if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
2779                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2780                         return false;
2781                 }
2782         }
2783
2784         return true;
2785 }
2786
2787 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2788 {
2789         static const char *tempfile_suffix = ".metadata_edit";
2790         if(0 == tempfile_path_prefix) {
2791                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
2792                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2793                         return false;
2794                 }
2795                 strcpy(*tempfilename, filename);
2796                 strcat(*tempfilename, tempfile_suffix);
2797         }
2798         else {
2799                 const char *p = strrchr(filename, '/');
2800                 if(0 == p)
2801                         p = filename;
2802                 else
2803                         p++;
2804
2805                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
2806                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2807                         return false;
2808                 }
2809                 strcpy(*tempfilename, tempfile_path_prefix);
2810                 strcat(*tempfilename, "/");
2811                 strcat(*tempfilename, p);
2812                 strcat(*tempfilename, tempfile_suffix);
2813         }
2814
2815         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
2816                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
2817                 return false;
2818         }
2819
2820         return true;
2821 }
2822
2823 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2824 {
2825         FLAC__ASSERT(0 != filename);
2826         FLAC__ASSERT(0 != tempfile);
2827         FLAC__ASSERT(0 != *tempfile);
2828         FLAC__ASSERT(0 != tempfilename);
2829         FLAC__ASSERT(0 != *tempfilename);
2830         FLAC__ASSERT(0 != status);
2831
2832         (void)fclose(*tempfile);
2833         *tempfile = 0;
2834
2835 #if defined _MSC_VER || defined __MINGW32__ || defined __EMX__
2836         if(unlink(filename) < 0) {
2837                 cleanup_tempfile_(tempfile, tempfilename);
2838                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
2839                 return false;
2840         }
2841 #endif
2842
2843         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
2844         if(0 != rename(*tempfilename, filename)) {
2845                 cleanup_tempfile_(tempfile, tempfilename);
2846                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
2847                 return false;
2848         }
2849
2850         cleanup_tempfile_(tempfile, tempfilename);
2851
2852         return true;
2853 }
2854
2855 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
2856 {
2857         if(0 != *tempfile) {
2858                 (void)fclose(*tempfile);
2859                 *tempfile = 0;
2860         }
2861
2862         if(0 != *tempfilename) {
2863                 (void)unlink(*tempfilename);
2864                 free(*tempfilename);
2865                 *tempfilename = 0;
2866         }
2867 }
2868
2869 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
2870 {
2871         FLAC__ASSERT(0 != filename);
2872         FLAC__ASSERT(0 != stats);
2873         return (0 == stat(filename, stats));
2874 }
2875
2876 void set_file_stats_(const char *filename, struct stat *stats)
2877 {
2878         struct utimbuf srctime;
2879
2880         FLAC__ASSERT(0 != filename);
2881         FLAC__ASSERT(0 != stats);
2882
2883         srctime.actime = stats->st_atime;
2884         srctime.modtime = stats->st_mtime;
2885         (void)chmod(filename, stats->st_mode);
2886         (void)utime(filename, &srctime);
2887 #if !defined _MSC_VER && !defined __MINGW32__ && !defined __EMX__
2888         (void)chown(filename, stats->st_uid, -1);
2889         (void)chown(filename, -1, stats->st_gid);
2890 #endif
2891 }
2892
2893 /* @@@ WATCHOUT @@@
2894  * We cast FLAC__int64 to long and use fseek()/ftell() because
2895  * none of our operations on metadata is ever likely to go past
2896  * 2 gigabytes.
2897  */
2898 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
2899 {
2900         FLAC__ASSERT(offset <= 0x7fffffff);
2901         return fseek((FILE*)handle, (long)offset, whence);
2902 }
2903
2904 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
2905 {
2906         return (long)ftell((FILE*)handle);
2907 }
2908
2909 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
2910 {
2911         switch(status) {
2912                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
2913                         return FLAC__METADATA_CHAIN_STATUS_OK;
2914                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
2915                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
2916                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
2917                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2918                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
2919                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
2920                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
2921                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
2922                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
2923                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
2924                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
2925                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
2926                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
2927                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2928                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
2929                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
2930                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
2931                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
2932                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
2933                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
2934                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
2935                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
2936                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
2937                 default:
2938                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
2939         }
2940 }