src/libFLAC/metadata_iterators.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2001,2002,2003,2004  Josh Coalson
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * - Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * - Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * - Neither the name of the Xiph.org Foundation nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <errno.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #if defined _MSC_VER || defined __MINGW32__
  38 #include <sys/utime.h> /* for utime() */
  39 #include <io.h> /* for chmod() */
  40 #else
  41 #include <sys/types.h> /* some flavors of BSD (like OS X) require this to get time_t */
  42 #include <utime.h> /* for utime() */
  43 #include <unistd.h> /* for chown(), unlink() */
  44 #endif
  45 #include <sys/stat.h> /* for stat(), maybe chmod() */
  46
  47 #include "private/metadata.h"
  48
  49 #include "FLAC/assert.h"
  50 #include "FLAC/file_decoder.h"
  51
  52 #ifdef max
  53 #undef max
  54 #endif
  55 #define max(a,b) ((a)>(b)?(a):(b))
  56 #ifdef min
  57 #undef min
  58 #endif
  59 #define min(a,b) ((a)<(b)?(a):(b))
  60
  61
  62 /****************************************************************************
  63  *
  64  * Local function declarations
  65  *
  66  ***************************************************************************/
  67
  68 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  69 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  70 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
  71 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
  72 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
  73 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
  74
  75 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
  76 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
  77 static FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length);
  78 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block);
  79 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block);
  80 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length);
  81 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length);
  82 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length);
  83 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry);
  84 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block);
  85 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track);
  86 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block);
  87 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length);
  88
  89 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  90 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  91 static FLAC__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__bool got_streaminfo;
 157         FLAC__StreamMetadata *streaminfo;
 158 } level0_client_data;
 159
 160 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 161 {
 162         level0_client_data cd;
 163         FLAC__FileDecoder *decoder;
 164
 165         FLAC__ASSERT(0 != filename);
 166         FLAC__ASSERT(0 != streaminfo);
 167
 168         decoder = FLAC__file_decoder_new();
 169
 170         if(0 == decoder)
 171                 return false;
 172
 173         cd.got_error = false;
 174         cd.got_streaminfo = false;
 175         cd.streaminfo = streaminfo;
 176
 177         FLAC__file_decoder_set_md5_checking(decoder, false);
 178         FLAC__file_decoder_set_filename(decoder, filename);
 179         FLAC__file_decoder_set_metadata_ignore_all(decoder);
 180         FLAC__file_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO);
 181         FLAC__file_decoder_set_write_callback(decoder, write_callback_);
 182         FLAC__file_decoder_set_metadata_callback(decoder, metadata_callback_);
 183         FLAC__file_decoder_set_error_callback(decoder, error_callback_);
 184         FLAC__file_decoder_set_client_data(decoder, &cd);
 185
 186         if(FLAC__file_decoder_init(decoder) != FLAC__FILE_DECODER_OK || cd.got_error) {
 187                 FLAC__file_decoder_finish(decoder);
 188                 FLAC__file_decoder_delete(decoder);
 189                 return false;
 190         }
 191
 192         /* the first thing decoded must be the STREAMINFO block: */
 193         if(!FLAC__file_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
 194                 FLAC__file_decoder_finish(decoder);
 195                 FLAC__file_decoder_delete(decoder);
 196                 return false;
 197         }
 198
 199         FLAC__file_decoder_finish(decoder);
 200         FLAC__file_decoder_delete(decoder);
 201
 202         return !cd.got_error && cd.got_streaminfo;
 203 }
 204
 205 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 206 {
 207         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 208
 209         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 210 }
 211
 212 void metadata_callback_(const FLAC__FileDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 213 {
 214         level0_client_data *cd = (level0_client_data *)client_data;
 215         (void)decoder;
 216
 217         if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO && 0 != cd->streaminfo) {
 218                 *(cd->streaminfo) = *metadata;
 219                 cd->got_streaminfo = true;
 220         }
 221 }
 222
 223 void error_callback_(const FLAC__FileDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 224 {
 225         level0_client_data *cd = (level0_client_data *)client_data;
 226         (void)decoder;
 227
 228         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 229                 cd->got_error = true;
 230 }
 231
 232
 233 /****************************************************************************
 234  *
 235  * Level 1 implementation
 236  *
 237  ***************************************************************************/
 238
 239 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 240 /* 1 for initial offset, +4 for our own personal use */
 241
 242 struct FLAC__Metadata_SimpleIterator {
 243         FILE *file;
 244         char *filename, *tempfile_path_prefix;
 245         struct stat stats;
 246         FLAC__bool has_stats;
 247         FLAC__bool is_writable;
 248         FLAC__Metadata_SimpleIteratorStatus status;
 249         /*@@@ 2G limits here because of the offset type: */
 250         long offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 251         long first_offset; /* this is the offset to the STREAMINFO block */
 252         unsigned depth;
 253         /* this is the metadata block header of the current block we are pointing to: */
 254         FLAC__bool is_last;
 255         FLAC__MetadataType type;
 256         unsigned length;
 257 };
 258
 259 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 260         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 261         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 262         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 263         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 264         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 265         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 266         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 267         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 268         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 269         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 270         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 271         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 272         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 273 };
 274
 275
 276 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 277 {
 278         FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 279
 280         if(0 != iterator) {
 281                 iterator->file = 0;
 282                 iterator->filename = 0;
 283                 iterator->tempfile_path_prefix = 0;
 284                 iterator->has_stats = false;
 285                 iterator->is_writable = false;
 286                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 287                 iterator->first_offset = iterator->offset[0] = -1;
 288                 iterator->depth = 0;
 289         }
 290
 291         return iterator;
 292 }
 293
 294 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 295 {
 296         FLAC__ASSERT(0 != iterator);
 297
 298         if(0 != iterator->file) {
 299                 fclose(iterator->file);
 300                 iterator->file = 0;
 301                 if(iterator->has_stats)
 302                         set_file_stats_(iterator->filename, &iterator->stats);
 303         }
 304         if(0 != iterator->filename) {
 305                 free(iterator->filename);
 306                 iterator->filename = 0;
 307         }
 308         if(0 != iterator->tempfile_path_prefix) {
 309                 free(iterator->tempfile_path_prefix);
 310                 iterator->tempfile_path_prefix = 0;
 311         }
 312 }
 313
 314 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 315 {
 316         FLAC__ASSERT(0 != iterator);
 317
 318         simple_iterator_free_guts_(iterator);
 319         free(iterator);
 320 }
 321
 322 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 323 {
 324         FLAC__Metadata_SimpleIteratorStatus status;
 325
 326         FLAC__ASSERT(0 != iterator);
 327
 328         status = iterator->status;
 329         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 330         return status;
 331 }
 332
 333 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
 334 {
 335         unsigned ret;
 336
 337         FLAC__ASSERT(0 != iterator);
 338
 339         if(read_only || 0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 340                 iterator->is_writable = false;
 341                 if(read_only || errno == EACCES) {
 342                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 343                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 344                                 return false;
 345                         }
 346                 }
 347                 else {
 348                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 349                         return false;
 350                 }
 351         }
 352         else {
 353                 iterator->is_writable = true;
 354         }
 355
 356         ret = seek_to_first_metadata_block_(iterator->file);
 357         switch(ret) {
 358                 case 0:
 359                         iterator->depth = 0;
 360                         iterator->first_offset = iterator->offset[iterator->depth] = ftell(iterator->file);
 361                         return read_metadata_block_header_(iterator);
 362                 case 1:
 363                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 364                         return false;
 365                 case 2:
 366                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 367                         return false;
 368                 case 3:
 369                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 370                         return false;
 371                 default:
 372                         FLAC__ASSERT(0);
 373                         return false;
 374         }
 375 }
 376
 377 #if 0
 378 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 379 /*
 380  * The 'tempfile_path_prefix' allows you to specify a directory where
 381  * tempfiles should go.  Remember that if your metadata edits cause the
 382  * FLAC file to grow, the entire file will have to be rewritten.  If
 383  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 384  * same directory as the original FLAC file.  This makes replacing the
 385  * original with the tempfile fast but requires extra space in the same
 386  * partition for the tempfile.  If space is a problem, you can pass a
 387  * directory name belonging to a different partition in
 388  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 389  * '/' as the directory separator.  A trailing slash is not needed; it
 390  * will be added automatically.
 391  */
 392 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 393 #endif
 394
 395 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)
 396 {
 397         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 398
 399         FLAC__ASSERT(0 != iterator);
 400         FLAC__ASSERT(0 != filename);
 401
 402         simple_iterator_free_guts_(iterator);
 403
 404         if(!read_only && preserve_file_stats)
 405                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 406
 407         if(0 == (iterator->filename = strdup(filename))) {
 408                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 409                 return false;
 410         }
 411         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 412                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 413                 return false;
 414         }
 415
 416         return simple_iterator_prime_input_(iterator, read_only);
 417 }
 418
 419 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 420 {
 421         FLAC__ASSERT(0 != iterator);
 422         FLAC__ASSERT(0 != iterator->file);
 423
 424         return iterator->is_writable;
 425 }
 426
 427 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 428 {
 429         FLAC__ASSERT(0 != iterator);
 430         FLAC__ASSERT(0 != iterator->file);
 431
 432         if(iterator->is_last)
 433                 return false;
 434
 435         if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 436                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 437                 return false;
 438         }
 439
 440         iterator->offset[iterator->depth] = ftell(iterator->file);
 441
 442         return read_metadata_block_header_(iterator);
 443 }
 444
 445 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 446 {
 447         long this_offset;
 448
 449         FLAC__ASSERT(0 != iterator);
 450         FLAC__ASSERT(0 != iterator->file);
 451
 452         if(iterator->offset[iterator->depth] == iterator->first_offset)
 453                 return false;
 454
 455         if(0 != fseek(iterator->file, iterator->first_offset, SEEK_SET)) {
 456                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 457                 return false;
 458         }
 459         this_offset = iterator->first_offset;
 460         if(!read_metadata_block_header_(iterator))
 461                 return false;
 462
 463         /* we ignore any error from ftell() and catch it in fseek() */
 464         while(ftell(iterator->file) + (long)iterator->length < iterator->offset[iterator->depth]) {
 465                 if(0 != fseek(iterator->file, iterator->length, SEEK_CUR)) {
 466                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 467                         return false;
 468                 }
 469                 this_offset = ftell(iterator->file);
 470                 if(!read_metadata_block_header_(iterator))
 471                         return false;
 472         }
 473
 474         iterator->offset[iterator->depth] = this_offset;
 475
 476         return true;
 477 }
 478
 479 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 480 {
 481         FLAC__ASSERT(0 != iterator);
 482         FLAC__ASSERT(0 != iterator->file);
 483
 484         return iterator->type;
 485 }
 486
 487 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 488 {
 489         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 490
 491         FLAC__ASSERT(0 != iterator);
 492         FLAC__ASSERT(0 != iterator->file);
 493
 494         if(0 != block) {
 495                 block->is_last = iterator->is_last;
 496                 block->length = iterator->length;
 497
 498                 if(!read_metadata_block_data_(iterator, block)) {
 499                         FLAC__metadata_object_delete(block);
 500                         return 0;
 501                 }
 502
 503                 /* back up to the beginning of the block data to stay consistent */
 504                 if(0 != fseek(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 505                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 506                         FLAC__metadata_object_delete(block);
 507                         return 0;
 508                 }
 509         }
 510         else
 511                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 512
 513         return block;
 514 }
 515
 516 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 517 {
 518         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 519         FLAC__bool ret;
 520
 521         FLAC__ASSERT(0 != iterator);
 522         FLAC__ASSERT(0 != iterator->file);
 523         FLAC__ASSERT(0 != block);
 524
 525         if(!iterator->is_writable) {
 526                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 527                 return false;
 528         }
 529
 530         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 531                 if(iterator->type != block->type) {
 532                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 533                         return false;
 534                 }
 535         }
 536
 537         block->is_last = iterator->is_last;
 538
 539         if(iterator->length == block->length)
 540                 return write_metadata_block_stationary_(iterator, block);
 541         else if(iterator->length > block->length) {
 542                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 543                         ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 544                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 545                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 546                         return ret;
 547                 }
 548                 else {
 549                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 550                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 551                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 552                         return ret;
 553                 }
 554         }
 555         else /* iterator->length < block->length */ {
 556                 unsigned padding_leftover = 0;
 557                 FLAC__bool padding_is_last = false;
 558                 if(use_padding) {
 559                         /* first see if we can even use padding */
 560                         if(iterator->is_last) {
 561                                 use_padding = false;
 562                         }
 563                         else {
 564                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 565                                 simple_iterator_push_(iterator);
 566                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 567                                         (void)simple_iterator_pop_(iterator);
 568                                         return false;
 569                                 }
 570                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 571                                         use_padding = false;
 572                                 }
 573                                 else {
 574                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 575                                                 padding_leftover = 0;
 576                                                 block->is_last = iterator->is_last;
 577                                         }
 578                                         else if(iterator->length < extra_padding_bytes_required)
 579                                                 use_padding = false;
 580                                         else {
 581                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 582                                                 padding_is_last = iterator->is_last;
 583                                                 block->is_last = false;
 584                                         }
 585                                 }
 586                                 if(!simple_iterator_pop_(iterator))
 587                                         return false;
 588                         }
 589                 }
 590                 if(use_padding) {
 591                         if(padding_leftover == 0) {
 592                                 ret = write_metadata_block_stationary_(iterator, block);
 593                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 594                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 595                                 return ret;
 596                         }
 597                         else {
 598                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 599                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 600                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 601                                 FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 602                                 return ret;
 603                         }
 604                 }
 605                 else {
 606                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 607                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 608                         FLAC__ASSERT(!ret || ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 609                         return ret;
 610                 }
 611         }
 612 }
 613
 614 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 615 {
 616         unsigned padding_leftover = 0;
 617         FLAC__bool padding_is_last = false;
 618
 619         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 620         FLAC__bool ret;
 621
 622         FLAC__ASSERT(0 != iterator);
 623         FLAC__ASSERT(0 != iterator->file);
 624         FLAC__ASSERT(0 != block);
 625
 626         if(!iterator->is_writable)
 627                 return false;
 628
 629         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 630                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 631                 return false;
 632         }
 633
 634         block->is_last = iterator->is_last;
 635
 636         if(use_padding) {
 637                 /* first see if we can even use padding */
 638                 if(iterator->is_last) {
 639                         use_padding = false;
 640                 }
 641                 else {
 642                         simple_iterator_push_(iterator);
 643                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 644                                 (void)simple_iterator_pop_(iterator);
 645                                 return false;
 646                         }
 647                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 648                                 use_padding = false;
 649                         }
 650                         else {
 651                                 if(iterator->length == block->length) {
 652                                         padding_leftover = 0;
 653                                         block->is_last = iterator->is_last;
 654                                 }
 655                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 656                                         use_padding = false;
 657                                 else {
 658                                         padding_leftover = iterator->length - block->length;
 659                                         padding_is_last = iterator->is_last;
 660                                         block->is_last = false;
 661                                 }
 662                         }
 663                         if(!simple_iterator_pop_(iterator))
 664                                 return false;
 665                 }
 666         }
 667         if(use_padding) {
 668                 /* move to the next block, which is suitable padding */
 669                 if(!FLAC__metadata_simple_iterator_next(iterator))
 670                         return false;
 671                 if(padding_leftover == 0) {
 672                         ret = write_metadata_block_stationary_(iterator, block);
 673                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 674                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 675                         return ret;
 676                 }
 677                 else {
 678                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 679                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 680                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 681                         FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 682                         return ret;
 683                 }
 684         }
 685         else {
 686                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 687                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 688                 FLAC__ASSERT(ftell(iterator->file) == debug_target_offset + (long)FLAC__STREAM_METADATA_HEADER_LENGTH);
 689                 return ret;
 690         }
 691 }
 692
 693 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 694 {
 695         FLAC__ASSERT_DECLARATION(long debug_target_offset = iterator->offset[iterator->depth];)
 696         FLAC__bool ret;
 697
 698         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 699                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 700                 return false;
 701         }
 702
 703         if(use_padding) {
 704                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 705                 if(0 == padding) {
 706                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 707                         return false;
 708                 }
 709                 padding->length = iterator->length;
 710                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 711                         FLAC__metadata_object_delete(padding);
 712                         return false;
 713                 }
 714                 FLAC__metadata_object_delete(padding);
 715                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 716                         return false;
 717                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 718                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 719                 return true;
 720         }
 721         else {
 722                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 723                 FLAC__ASSERT(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length == debug_target_offset);
 724                 FLAC__ASSERT(ftell(iterator->file) + (long)iterator->length == debug_target_offset);
 725                 return ret;
 726         }
 727 }
 728
 729
 730
 731 /****************************************************************************
 732  *
 733  * Level 2 implementation
 734  *
 735  ***************************************************************************/
 736
 737
 738 typedef struct FLAC__Metadata_Node {
 739         FLAC__StreamMetadata *data;
 740         struct FLAC__Metadata_Node *prev, *next;
 741 } FLAC__Metadata_Node;
 742
 743 struct FLAC__Metadata_Chain {
 744         char *filename; /* will be NULL if using callbacks */
 745         FLAC__Metadata_Node *head;
 746         FLAC__Metadata_Node *tail;
 747         unsigned nodes;
 748         FLAC__Metadata_ChainStatus status;
 749         long first_offset, last_offset; /*@@@ 2G limit */
 750         /*
 751          * This is the length of the chain initially read from the FLAC file.
 752          * it is used to compare against the current length to decide whether
 753          * or not the whole file has to be rewritten.
 754          */
 755         unsigned initial_length; /*@@@ 4G limit */
 756 };
 757
 758 struct FLAC__Metadata_Iterator {
 759         FLAC__Metadata_Chain *chain;
 760         FLAC__Metadata_Node *current;
 761 };
 762
 763 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 764         "FLAC__METADATA_CHAIN_STATUS_OK",
 765         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 766         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 767         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 768         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 769         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 770         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 771         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 772         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 773         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 774         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 775         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 776         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
 777         "FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
 778         "FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
 779         "FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
 780 };
 781
 782
 783 static FLAC__Metadata_Node *node_new_()
 784 {
 785         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 786 }
 787
 788 static void node_delete_(FLAC__Metadata_Node *node)
 789 {
 790         FLAC__ASSERT(0 != node);
 791         if(0 != node->data)
 792                 FLAC__metadata_object_delete(node->data);
 793         free(node);
 794 }
 795
 796 static void chain_init_(FLAC__Metadata_Chain *chain)
 797 {
 798         FLAC__ASSERT(0 != chain);
 799
 800         chain->filename = 0;
 801         chain->head = chain->tail = 0;
 802         chain->nodes = 0;
 803         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 804         chain->initial_length = 0;
 805 }
 806
 807 static void chain_clear_(FLAC__Metadata_Chain *chain)
 808 {
 809         FLAC__Metadata_Node *node, *next;
 810
 811         FLAC__ASSERT(0 != chain);
 812
 813         for(node = chain->head; node; ) {
 814                 next = node->next;
 815                 node_delete_(node);
 816                 node = next;
 817         }
 818
 819         if(0 != chain->filename)
 820                 free(chain->filename);
 821
 822         chain_init_(chain);
 823 }
 824
 825 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 826 {
 827         FLAC__ASSERT(0 != chain);
 828         FLAC__ASSERT(0 != node);
 829         FLAC__ASSERT(0 != node->data);
 830
 831         node->next = node->prev = 0;
 832         node->data->is_last = true;
 833         if(0 != chain->tail)
 834                 chain->tail->data->is_last = false;
 835
 836         if(0 == chain->head)
 837                 chain->head = node;
 838         else {
 839                 FLAC__ASSERT(0 != chain->tail);
 840                 chain->tail->next = node;
 841                 node->prev = chain->tail;
 842         }
 843         chain->tail = node;
 844         chain->nodes++;
 845 }
 846
 847 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 848 {
 849         FLAC__ASSERT(0 != chain);
 850         FLAC__ASSERT(0 != node);
 851
 852         if(node == chain->head)
 853                 chain->head = node->next;
 854         else
 855                 node->prev->next = node->next;
 856
 857         if(node == chain->tail)
 858                 chain->tail = node->prev;
 859         else
 860                 node->next->prev = node->prev;
 861
 862         if(0 != chain->tail)
 863                 chain->tail->data->is_last = true;
 864
 865         chain->nodes--;
 866 }
 867
 868 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 869 {
 870         chain_remove_node_(chain, node);
 871         node_delete_(node);
 872 }
 873
 874 static unsigned chain_calculate_length_(FLAC__Metadata_Chain *chain)
 875 {
 876         const FLAC__Metadata_Node *node;
 877         unsigned length = 0;
 878         for(node = chain->head; node; node = node->next)
 879                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 880         return length;
 881 }
 882
 883 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 884 {
 885         FLAC__ASSERT(0 != node);
 886         FLAC__ASSERT(0 != node->data);
 887         FLAC__ASSERT(0 != iterator);
 888         FLAC__ASSERT(0 != iterator->current);
 889         FLAC__ASSERT(0 != iterator->chain);
 890         FLAC__ASSERT(0 != iterator->chain->head);
 891         FLAC__ASSERT(0 != iterator->chain->tail);
 892
 893         node->data->is_last = false;
 894
 895         node->prev = iterator->current->prev;
 896         node->next = iterator->current;
 897
 898         if(0 == node->prev)
 899                 iterator->chain->head = node;
 900         else
 901                 node->prev->next = node;
 902
 903         iterator->current->prev = node;
 904
 905         iterator->chain->nodes++;
 906 }
 907
 908 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 909 {
 910         FLAC__ASSERT(0 != node);
 911         FLAC__ASSERT(0 != node->data);
 912         FLAC__ASSERT(0 != iterator);
 913         FLAC__ASSERT(0 != iterator->current);
 914         FLAC__ASSERT(0 != iterator->chain);
 915         FLAC__ASSERT(0 != iterator->chain->head);
 916         FLAC__ASSERT(0 != iterator->chain->tail);
 917
 918         iterator->current->data->is_last = false;
 919
 920         node->prev = iterator->current;
 921         node->next = iterator->current->next;
 922
 923         if(0 == node->next)
 924                 iterator->chain->tail = node;
 925         else
 926                 node->next->prev = node;
 927
 928         node->prev->next = node;
 929
 930         iterator->chain->tail->data->is_last = true;
 931
 932         iterator->chain->nodes++;
 933 }
 934
 935 /* return true iff node and node->next are both padding */
 936 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 937 {
 938         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
 939                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
 940                 node->data->length += growth;
 941
 942                 chain_delete_node_(chain, node->next);
 943                 return true;
 944         }
 945         else
 946                 return false;
 947 }
 948
 949 /* Returns the new length of the chain, or 0 if there was an error. */
 950 /* WATCHOUT: This can get called multiple times before a write, so
 951  * it should still work when this happens.
 952  */
 953 /* WATCHOUT: Make sure to also update the logic in
 954  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
 955  */
 956 static unsigned chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
 957 {
 958         unsigned current_length = chain_calculate_length_(chain);
 959
 960         if(use_padding) {
 961                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
 962                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
 963                         const unsigned delta = chain->initial_length - current_length;
 964                         chain->tail->data->length += delta;
 965                         current_length += delta;
 966                         FLAC__ASSERT(current_length == chain->initial_length);
 967                 }
 968                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
 969                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
 970                         FLAC__StreamMetadata *padding;
 971                         FLAC__Metadata_Node *node;
 972                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
 973                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 974                                 return 0;
 975                         }
 976                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
 977                         if(0 == (node = node_new_())) {
 978                                 FLAC__metadata_object_delete(padding);
 979                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
 980                                 return 0;
 981                         }
 982                         node->data = padding;
 983                         chain_append_node_(chain, node);
 984                         current_length = chain_calculate_length_(chain);
 985                         FLAC__ASSERT(current_length == chain->initial_length);
 986                 }
 987                 /* 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 */
 988                 else if(current_length > chain->initial_length) {
 989                         const unsigned delta = current_length - chain->initial_length;
 990                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
 991                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
 992                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
 993                                         chain_delete_node_(chain, chain->tail);
 994                                         current_length = chain_calculate_length_(chain);
 995                                         FLAC__ASSERT(current_length == chain->initial_length);
 996                                 }
 997                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
 998                                 else if(chain->tail->data->length >= delta) {
 999                                         chain->tail->data->length -= delta;
1000                                         current_length -= delta;
1001                                         FLAC__ASSERT(current_length == chain->initial_length);
1002                                 }
1003                         }
1004                 }
1005         }
1006
1007         return current_length;
1008 }
1009
1010 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)
1011 {
1012         FLAC__Metadata_Node *node;
1013
1014         FLAC__ASSERT(0 != chain);
1015
1016         /* we assume we're already at the beginning of the file */
1017
1018         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
1019                 case 0:
1020                         break;
1021                 case 1:
1022                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1023                         return false;
1024                 case 2:
1025                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1026                         return false;
1027                 case 3:
1028                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
1029                         return false;
1030                 default:
1031                         FLAC__ASSERT(0);
1032                         return false;
1033         }
1034
1035         {
1036                 FLAC__int64 pos = tell_cb(handle);
1037                 if(pos < 0) {
1038                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1039                         return false;
1040                 }
1041                 chain->first_offset = (long)pos;
1042         }
1043
1044         {
1045                 FLAC__bool is_last;
1046                 FLAC__MetadataType type;
1047                 unsigned length;
1048
1049                 do {
1050                         node = node_new_();
1051                         if(0 == node) {
1052                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1053                                 return false;
1054                         }
1055
1056                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
1057                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1058                                 return false;
1059                         }
1060
1061                         node->data = FLAC__metadata_object_new(type);
1062                         if(0 == node->data) {
1063                                 node_delete_(node);
1064                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1065                                 return false;
1066                         }
1067
1068                         node->data->is_last = is_last;
1069                         node->data->length = length;
1070
1071                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
1072                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1073                                 node_delete_(node);
1074                                 return false;
1075                         }
1076                         chain_append_node_(chain, node);
1077                 } while(!is_last);
1078         }
1079
1080         {
1081                 FLAC__int64 pos = tell_cb(handle);
1082                 if(pos < 0) {
1083                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1084                         return false;
1085                 }
1086                 chain->last_offset = (long)pos;
1087         }
1088
1089         chain->initial_length = chain_calculate_length_(chain);
1090
1091         return true;
1092 }
1093
1094 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)
1095 {
1096         FLAC__Metadata_Node *node;
1097
1098         FLAC__ASSERT(0 != chain);
1099         FLAC__ASSERT(0 != chain->head);
1100
1101         if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
1102                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1103                 return false;
1104         }
1105
1106         for(node = chain->head; node; node = node->next) {
1107                 if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
1108                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1109                         return false;
1110                 }
1111                 if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
1112                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1113                         return false;
1114                 }
1115         }
1116
1117         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1118
1119         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1120         return true;
1121 }
1122
1123 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
1124 {
1125         FILE *file;
1126         FLAC__bool ret;
1127
1128         FLAC__ASSERT(0 != chain->filename);
1129
1130         if(0 == (file = fopen(chain->filename, "r+b"))) {
1131                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1132                 return false;
1133         }
1134
1135         /* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
1136         ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
1137
1138         fclose(file);
1139
1140         return ret;
1141 }
1142
1143 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1144 {
1145         FILE *f, *tempfile;
1146         char *tempfilename;
1147         FLAC__Metadata_SimpleIteratorStatus status;
1148         const FLAC__Metadata_Node *node;
1149
1150         FLAC__ASSERT(0 != chain);
1151         FLAC__ASSERT(0 != chain->filename);
1152         FLAC__ASSERT(0 != chain->head);
1153
1154         /* copy the file prefix (data up to first metadata block */
1155         if(0 == (f = fopen(chain->filename, "rb"))) {
1156                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1157                 return false;
1158         }
1159         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1160                 chain->status = get_equivalent_status_(status);
1161                 cleanup_tempfile_(&tempfile, &tempfilename);
1162                 return false;
1163         }
1164         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1165                 chain->status = get_equivalent_status_(status);
1166                 cleanup_tempfile_(&tempfile, &tempfilename);
1167                 return false;
1168         }
1169
1170         /* write the metadata */
1171         for(node = chain->head; node; node = node->next) {
1172                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1173                         chain->status = get_equivalent_status_(status);
1174                         return false;
1175                 }
1176                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1177                         chain->status = get_equivalent_status_(status);
1178                         return false;
1179                 }
1180         }
1181         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1182
1183         /* copy the file postfix (everything after the metadata) */
1184         if(0 != fseek(f, chain->last_offset, SEEK_SET)) {
1185                 cleanup_tempfile_(&tempfile, &tempfilename);
1186                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1187                 return false;
1188         }
1189         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1190                 cleanup_tempfile_(&tempfile, &tempfilename);
1191                 chain->status = get_equivalent_status_(status);
1192                 return false;
1193         }
1194
1195         /* move the tempfile on top of the original */
1196         (void)fclose(f);
1197         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1198                 return false;
1199
1200         return true;
1201 }
1202
1203 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)
1204 {
1205         FLAC__Metadata_SimpleIteratorStatus status;
1206         const FLAC__Metadata_Node *node;
1207
1208         FLAC__ASSERT(0 != chain);
1209         FLAC__ASSERT(0 == chain->filename);
1210         FLAC__ASSERT(0 != chain->head);
1211
1212         /* copy the file prefix (data up to first metadata block */
1213         if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
1214                 chain->status = get_equivalent_status_(status);
1215                 return false;
1216         }
1217
1218         /* write the metadata */
1219         for(node = chain->head; node; node = node->next) {
1220                 if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
1221                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1222                         return false;
1223                 }
1224                 if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
1225                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1226                         return false;
1227                 }
1228         }
1229         /*FLAC__ASSERT(fflush(), ftell() == chain->last_offset);*/
1230
1231         /* copy the file postfix (everything after the metadata) */
1232         if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
1233                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1234                 return false;
1235         }
1236         if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
1237                 chain->status = get_equivalent_status_(status);
1238                 return false;
1239         }
1240
1241         return true;
1242 }
1243
1244 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1245 {
1246         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1247
1248         if(0 != chain)
1249                 chain_init_(chain);
1250
1251         return chain;
1252 }
1253
1254 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1255 {
1256         FLAC__ASSERT(0 != chain);
1257
1258         chain_clear_(chain);
1259
1260         free(chain);
1261 }
1262
1263 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1264 {
1265         FLAC__Metadata_ChainStatus status;
1266
1267         FLAC__ASSERT(0 != chain);
1268
1269         status = chain->status;
1270         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1271         return status;
1272 }
1273
1274 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1275 {
1276         FILE *file;
1277         FLAC__bool ret;
1278
1279         FLAC__ASSERT(0 != chain);
1280         FLAC__ASSERT(0 != filename);
1281
1282         chain_clear_(chain);
1283
1284         if(0 == (chain->filename = strdup(filename))) {
1285                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1286                 return false;
1287         }
1288
1289         if(0 == (file = fopen(filename, "rb"))) {
1290                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1291                 return false;
1292         }
1293
1294         /* chain_read_cb_() sets chain->status for us */
1295         ret = chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_);
1296
1297         fclose(file);
1298
1299         return ret;
1300 }
1301
1302 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1303 {
1304         FLAC__ASSERT(0 != chain);
1305
1306         chain_clear_(chain);
1307
1308         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
1309                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1310                 return false;
1311         }
1312
1313         if(!chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell))
1314                 return false; /* chain->status is already set by chain_read_cb_ */
1315
1316         return true;
1317 }
1318
1319 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1320 {
1321         /* This does all the same checks that are in chain_prepare_for_write_()
1322          * but doesn't actually alter the chain.  Make sure to update the logic
1323          * here if chain_prepare_for_write_() changes.
1324          */
1325         const unsigned current_length = chain_calculate_length_(chain);
1326
1327         FLAC__ASSERT(0 != chain);
1328
1329         if(use_padding) {
1330                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1331                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING)
1332                         return false;
1333                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1334                 else if(current_length + FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length)
1335                         return false;
1336                 /* 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 */
1337                 else if(current_length > chain->initial_length) {
1338                         const unsigned delta = current_length - chain->initial_length;
1339                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1340                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1341                                 if(chain->tail->data->length + FLAC__STREAM_METADATA_HEADER_LENGTH == delta)
1342                                         return false;
1343                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1344                                 else if(chain->tail->data->length >= delta)
1345                                         return false;
1346                         }
1347                 }
1348         }
1349
1350         return (current_length != chain->initial_length);
1351 }
1352
1353 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1354 {
1355         struct stat stats;
1356         const char *tempfile_path_prefix = 0;
1357         unsigned current_length;
1358
1359         FLAC__ASSERT(0 != chain);
1360
1361         if (0 == chain->filename) {
1362                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1363                 return false;
1364         }
1365
1366         current_length = chain_prepare_for_write_(chain, use_padding);
1367
1368         /* a return value of 0 means there was an error; chain->status is already set */
1369         if (0 == current_length)
1370                 return false;
1371
1372         if(preserve_file_stats)
1373                 get_file_stats_(chain->filename, &stats);
1374
1375         if(current_length == chain->initial_length) {
1376                 if(!chain_rewrite_metadata_in_place_(chain))
1377                         return false;
1378         }
1379         else {
1380                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1381                         return false;
1382
1383                 /* recompute lengths and offsets */
1384                 {
1385                         const FLAC__Metadata_Node *node;
1386                         chain->initial_length = current_length;
1387                         chain->last_offset = chain->first_offset;
1388                         for(node = chain->head; node; node = node->next)
1389                                 chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1390                 }
1391         }
1392
1393         if(preserve_file_stats)
1394                 set_file_stats_(chain->filename, &stats);
1395
1396         return true;
1397 }
1398
1399 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1400 {
1401         unsigned current_length;
1402         FLAC__bool ret;
1403
1404         FLAC__ASSERT(0 != chain);
1405
1406         if (0 != chain->filename) {
1407                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1408                 return false;
1409         }
1410
1411         if (0 == callbacks.write || 0 == callbacks.seek) {
1412                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1413                 return false;
1414         }
1415
1416         if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1417                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1418                 return false;
1419         }
1420
1421         current_length = chain_prepare_for_write_(chain, use_padding);
1422
1423         /* a return value of 0 means there was an error; chain->status is already set */
1424         if (0 == current_length)
1425                 return false;
1426
1427         FLAC__ASSERT(current_length == chain->initial_length);
1428
1429         return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
1430 }
1431
1432 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)
1433 {
1434         unsigned current_length;
1435
1436         FLAC__ASSERT(0 != chain);
1437
1438         if (0 != chain->filename) {
1439                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1440                 return false;
1441         }
1442
1443         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
1444                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1445                 return false;
1446         }
1447         if (0 == temp_callbacks.write) {
1448                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1449                 return false;
1450         }
1451
1452         if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1453                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1454                 return false;
1455         }
1456
1457         current_length = chain_prepare_for_write_(chain, use_padding);
1458
1459         /* a return value of 0 means there was an error; chain->status is already set */
1460         if (0 == current_length)
1461                 return false;
1462
1463         FLAC__ASSERT(current_length != chain->initial_length);
1464
1465         if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
1466                 return false;
1467
1468         /* recompute lengths and offsets */
1469         {
1470                 const FLAC__Metadata_Node *node;
1471                 chain->initial_length = current_length;
1472                 chain->last_offset = chain->first_offset;
1473                 for(node = chain->head; node; node = node->next)
1474                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1475         }
1476
1477         return true;
1478 }
1479
1480 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1481 {
1482         FLAC__Metadata_Node *node;
1483
1484         FLAC__ASSERT(0 != chain);
1485
1486         for(node = chain->head; node; ) {
1487                 if(!chain_merge_adjacent_padding_(chain, node))
1488                         node = node->next;
1489         }
1490 }
1491
1492 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1493 {
1494         FLAC__Metadata_Node *node, *save;
1495         unsigned i;
1496
1497         FLAC__ASSERT(0 != chain);
1498
1499         /*
1500          * Don't try and be too smart... this simple algo is good enough for
1501          * the small number of nodes that we deal with.
1502          */
1503         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1504                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1505                         save = node->next;
1506                         chain_remove_node_(chain, node);
1507                         chain_append_node_(chain, node);
1508                         node = save;
1509                 }
1510                 else {
1511                         node = node->next;
1512                 }
1513         }
1514
1515         FLAC__metadata_chain_merge_padding(chain);
1516 }
1517
1518
1519 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1520 {
1521         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1522
1523         /* calloc() implies:
1524                 iterator->current = 0;
1525                 iterator->chain = 0;
1526         */
1527
1528         return iterator;
1529 }
1530
1531 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1532 {
1533         FLAC__ASSERT(0 != iterator);
1534
1535         free(iterator);
1536 }
1537
1538 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1539 {
1540         FLAC__ASSERT(0 != iterator);
1541         FLAC__ASSERT(0 != chain);
1542         FLAC__ASSERT(0 != chain->head);
1543
1544         iterator->chain = chain;
1545         iterator->current = chain->head;
1546 }
1547
1548 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1549 {
1550         FLAC__ASSERT(0 != iterator);
1551
1552         if(0 == iterator->current || 0 == iterator->current->next)
1553                 return false;
1554
1555         iterator->current = iterator->current->next;
1556         return true;
1557 }
1558
1559 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1560 {
1561         FLAC__ASSERT(0 != iterator);
1562
1563         if(0 == iterator->current || 0 == iterator->current->prev)
1564                 return false;
1565
1566         iterator->current = iterator->current->prev;
1567         return true;
1568 }
1569
1570 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1571 {
1572         FLAC__ASSERT(0 != iterator);
1573         FLAC__ASSERT(0 != iterator->current);
1574         FLAC__ASSERT(0 != iterator->current->data);
1575
1576         return iterator->current->data->type;
1577 }
1578
1579 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1580 {
1581         FLAC__ASSERT(0 != iterator);
1582         FLAC__ASSERT(0 != iterator->current);
1583
1584         return iterator->current->data;
1585 }
1586
1587 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1588 {
1589         FLAC__ASSERT(0 != iterator);
1590         FLAC__ASSERT(0 != block);
1591         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1592 }
1593
1594 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1595 {
1596         FLAC__Metadata_Node *save;
1597
1598         FLAC__ASSERT(0 != iterator);
1599         FLAC__ASSERT(0 != iterator->current);
1600
1601         if(0 == iterator->current->prev) {
1602                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1603                 return false;
1604         }
1605
1606         save = iterator->current->prev;
1607
1608         if(replace_with_padding) {
1609                 FLAC__metadata_object_delete_data(iterator->current->data);
1610                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1611         }
1612         else {
1613                 chain_delete_node_(iterator->chain, iterator->current);
1614         }
1615
1616         iterator->current = save;
1617         return true;
1618 }
1619
1620 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1621 {
1622         FLAC__Metadata_Node *node;
1623
1624         FLAC__ASSERT(0 != iterator);
1625         FLAC__ASSERT(0 != iterator->current);
1626         FLAC__ASSERT(0 != block);
1627
1628         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1629                 return false;
1630
1631         if(0 == iterator->current->prev) {
1632                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1633                 return false;
1634         }
1635
1636         if(0 == (node = node_new_()))
1637                 return false;
1638
1639         node->data = block;
1640         iterator_insert_node_(iterator, node);
1641         iterator->current = node;
1642         return true;
1643 }
1644
1645 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1646 {
1647         FLAC__Metadata_Node *node;
1648
1649         FLAC__ASSERT(0 != iterator);
1650         FLAC__ASSERT(0 != iterator->current);
1651         FLAC__ASSERT(0 != block);
1652
1653         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1654                 return false;
1655
1656         if(0 == (node = node_new_()))
1657                 return false;
1658
1659         node->data = block;
1660         iterator_insert_node_after_(iterator, node);
1661         iterator->current = node;
1662         return true;
1663 }
1664
1665
1666 /****************************************************************************
1667  *
1668  * Local function definitions
1669  *
1670  ***************************************************************************/
1671
1672 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1673 {
1674         unsigned i;
1675
1676         b += bytes;
1677
1678         for(i = 0; i < bytes; i++) {
1679                 *(--b) = (FLAC__byte)(val & 0xff);
1680                 val >>= 8;
1681         }
1682 }
1683
1684 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1685 {
1686         unsigned i;
1687
1688         for(i = 0; i < bytes; i++) {
1689                 *(b++) = (FLAC__byte)(val & 0xff);
1690                 val >>= 8;
1691         }
1692 }
1693
1694 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1695 {
1696         unsigned i;
1697
1698         b += bytes;
1699
1700         for(i = 0; i < bytes; i++) {
1701                 *(--b) = (FLAC__byte)(val & 0xff);
1702                 val >>= 8;
1703         }
1704 }
1705
1706 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1707 {
1708         FLAC__uint32 ret = 0;
1709         unsigned i;
1710
1711         for(i = 0; i < bytes; i++)
1712                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1713
1714         return ret;
1715 }
1716
1717 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1718 {
1719         FLAC__uint32 ret = 0;
1720         unsigned i;
1721
1722         b += bytes;
1723
1724         for(i = 0; i < bytes; i++)
1725                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1726
1727         return ret;
1728 }
1729
1730 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1731 {
1732         FLAC__uint64 ret = 0;
1733         unsigned i;
1734
1735         for(i = 0; i < bytes; i++)
1736                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1737
1738         return ret;
1739 }
1740
1741 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1742 {
1743         FLAC__ASSERT(0 != iterator);
1744         FLAC__ASSERT(0 != iterator->file);
1745
1746         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1747                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1748                 return false;
1749         }
1750
1751         return true;
1752 }
1753
1754 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1755 {
1756         FLAC__ASSERT(0 != iterator);
1757         FLAC__ASSERT(0 != iterator->file);
1758
1759         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
1760
1761         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1762 }
1763
1764 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
1765 {
1766         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1767
1768         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
1769                 return false;
1770
1771         *is_last = raw_header[0] & 0x80? true : false;
1772         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1773         *length = unpack_uint32_(raw_header + 1, 3);
1774
1775         /* Note that we don't check:
1776          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
1777          * we just will read in an opaque block
1778          */
1779
1780         return true;
1781 }
1782
1783 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
1784 {
1785         switch(block->type) {
1786                 case FLAC__METADATA_TYPE_STREAMINFO:
1787                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
1788                 case FLAC__METADATA_TYPE_PADDING:
1789                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
1790                 case FLAC__METADATA_TYPE_APPLICATION:
1791                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
1792                 case FLAC__METADATA_TYPE_SEEKTABLE:
1793                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
1794                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1795                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
1796                 case FLAC__METADATA_TYPE_CUESHEET:
1797                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
1798                 default:
1799                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
1800         }
1801 }
1802
1803 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
1804 {
1805         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1806
1807         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1808                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1809
1810         b = buffer;
1811
1812         /* we are using hardcoded numbers for simplicity but we should
1813          * probably eventually write a bit-level unpacker and use the
1814          * _STREAMINFO_ constants.
1815          */
1816         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1817         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1818         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1819         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1820         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1821         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1822         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1823         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1824         memcpy(block->md5sum, b+8, 16);
1825
1826         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1827 }
1828
1829
1830 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1831 {
1832         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1833
1834         if(0 != seek_cb(handle, block_length, SEEK_CUR))
1835                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1836
1837         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1838 }
1839
1840 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
1841 {
1842         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1843
1844         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
1845                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1846
1847         block_length -= id_bytes;
1848
1849         if(block_length == 0) {
1850                 block->data = 0;
1851         }
1852         else {
1853                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1854                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1855
1856                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1857                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1858         }
1859
1860         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1861 }
1862
1863 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1864 {
1865         unsigned i;
1866         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1867
1868         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1869
1870         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1871
1872         if(block->num_points == 0)
1873                 block->points = 0;
1874         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1875                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1876
1877         for(i = 0; i < block->num_points; i++) {
1878                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1879                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1880                 /* some MAGIC NUMBERs here */
1881                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1882                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1883                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1884         }
1885
1886         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1887 }
1888
1889 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
1890 {
1891         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
1892         FLAC__byte buffer[4]; /* magic number is asserted below */
1893
1894         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == 4);
1895
1896         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
1897                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1898         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
1899
1900         if(0 != entry->entry)
1901                 free(entry->entry);
1902
1903         if(entry->length == 0) {
1904                 entry->entry = 0;
1905         }
1906         else {
1907                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length)))
1908                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1909
1910                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->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_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
1918 {
1919         unsigned i;
1920         FLAC__Metadata_SimpleIteratorStatus status;
1921         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
1922         FLAC__byte buffer[4]; /* magic number is asserted below */
1923
1924         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == 4);
1925
1926         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
1927                 return status;
1928
1929         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
1930                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1931         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
1932
1933         if(block->num_comments == 0) {
1934                 block->comments = 0;
1935         }
1936         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
1937                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1938
1939         for(i = 0; i < block->num_comments; i++) {
1940                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
1941                         return status;
1942         }
1943
1944         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1945 }
1946
1947 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
1948 {
1949         unsigned i, len;
1950         FLAC__byte buffer[32]; /* asserted below that this is big enough */
1951
1952         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
1953         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
1954         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);
1955
1956         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
1957         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
1958         if(read_cb(buffer, 1, len, handle) != len)
1959                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1960         track->offset = unpack_uint64_(buffer, len);
1961
1962         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
1963         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
1964         if(read_cb(buffer, 1, len, handle) != len)
1965                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1966         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
1967
1968         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
1969         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
1970         if(read_cb(track->isrc, 1, len, handle) != len)
1971                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1972
1973         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);
1974         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
1975         if(read_cb(buffer, 1, len, handle) != len)
1976                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1977         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
1978         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
1979         track->type = buffer[0] >> 7;
1980         track->pre_emphasis = (buffer[0] >> 6) & 1;
1981
1982         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
1983         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
1984         if(read_cb(buffer, 1, len, handle) != len)
1985                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1986         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
1987
1988         if(track->num_indices == 0) {
1989                 track->indices = 0;
1990         }
1991         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
1992                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1993
1994         for(i = 0; i < track->num_indices; i++) {
1995                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
1996                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
1997                 if(read_cb(buffer, 1, len, handle) != len)
1998                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1999                 track->indices[i].offset = unpack_uint64_(buffer, len);
2000
2001                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2002                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2003                 if(read_cb(buffer, 1, len, handle) != len)
2004                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2005                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
2006
2007                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2008                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2009                 if(read_cb(buffer, 1, len, handle) != len)
2010                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2011         }
2012
2013         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2014 }
2015
2016 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
2017 {
2018         unsigned i, len;
2019         FLAC__Metadata_SimpleIteratorStatus status;
2020         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
2021
2022         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
2023         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
2024
2025         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2026         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2027         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
2028                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2029
2030         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2031         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2032         if(read_cb(buffer, 1, len, handle) != len)
2033                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2034         block->lead_in = unpack_uint64_(buffer, len);
2035
2036         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2037         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2038         if(read_cb(buffer, 1, len, handle) != len)
2039                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2040         block->is_cd = buffer[0]&0x80? true : false;
2041
2042         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2043         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2044         if(read_cb(buffer, 1, len, handle) != len)
2045                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2046         block->num_tracks = unpack_uint32_(buffer, len);
2047
2048         if(block->num_tracks == 0) {
2049                 block->tracks = 0;
2050         }
2051         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
2052                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2053
2054         for(i = 0; i < block->num_tracks; i++) {
2055                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
2056                         return status;
2057         }
2058
2059         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2060 }
2061
2062 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2063 {
2064         if(block_length == 0) {
2065                 block->data = 0;
2066         }
2067         else {
2068                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2069                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2070
2071                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2072                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2073         }
2074
2075         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2076 }
2077
2078 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2079 {
2080         FLAC__ASSERT(0 != file);
2081         FLAC__ASSERT(0 != status);
2082
2083         if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2084                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2085                 return false;
2086         }
2087
2088         return true;
2089 }
2090
2091 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2092 {
2093         FLAC__ASSERT(0 != file);
2094         FLAC__ASSERT(0 != status);
2095
2096         if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2097                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2098                 return true;
2099         }
2100         else {
2101                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2102                 return false;
2103         }
2104 }
2105
2106 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2107 {
2108         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
2109
2110         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
2111
2112         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
2113         pack_uint32_(block->length, buffer + 1, 3);
2114
2115         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2116                 return false;
2117
2118         return true;
2119 }
2120
2121 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2122 {
2123         FLAC__ASSERT(0 != block);
2124
2125         switch(block->type) {
2126                 case FLAC__METADATA_TYPE_STREAMINFO:
2127                         return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
2128                 case FLAC__METADATA_TYPE_PADDING:
2129                         return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
2130                 case FLAC__METADATA_TYPE_APPLICATION:
2131                         return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
2132                 case FLAC__METADATA_TYPE_SEEKTABLE:
2133                         return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
2134                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2135                         return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
2136                 case FLAC__METADATA_TYPE_CUESHEET:
2137                         return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
2138                 default:
2139                         return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
2140         }
2141 }
2142
2143 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
2144 {
2145         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
2146         const unsigned channels1 = block->channels - 1;
2147         const unsigned bps1 = block->bits_per_sample - 1;
2148
2149         /* we are using hardcoded numbers for simplicity but we should
2150          * probably eventually write a bit-level packer and use the
2151          * _STREAMINFO_ constants.
2152          */
2153         pack_uint32_(block->min_blocksize, buffer, 2);
2154         pack_uint32_(block->max_blocksize, buffer+2, 2);
2155         pack_uint32_(block->min_framesize, buffer+4, 3);
2156         pack_uint32_(block->max_framesize, buffer+7, 3);
2157         buffer[10] = (block->sample_rate >> 12) & 0xff;
2158         buffer[11] = (block->sample_rate >> 4) & 0xff;
2159         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
2160         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
2161         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
2162         memcpy(buffer+18, block->md5sum, 16);
2163
2164         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2165                 return false;
2166
2167         return true;
2168 }
2169
2170 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
2171 {
2172         unsigned i, n = block_length;
2173         FLAC__byte buffer[1024];
2174
2175         (void)block;
2176
2177         memset(buffer, 0, 1024);
2178
2179         for(i = 0; i < n/1024; i++)
2180                 if(write_cb(buffer, 1, 1024, handle) != 1024)
2181                         return false;
2182
2183         n %= 1024;
2184
2185         if(write_cb(buffer, 1, n, handle) != n)
2186                 return false;
2187
2188         return true;
2189 }
2190
2191 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
2192 {
2193         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2194
2195         if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
2196                 return false;
2197
2198         block_length -= id_bytes;
2199
2200         if(write_cb(block->data, 1, block_length, handle) != block_length)
2201                 return false;
2202
2203         return true;
2204 }
2205
2206 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
2207 {
2208         unsigned i;
2209         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2210
2211         for(i = 0; i < block->num_points; i++) {
2212                 /* some MAGIC NUMBERs here */
2213                 pack_uint64_(block->points[i].sample_number, buffer, 8);
2214                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
2215                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
2216                 if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2217                         return false;
2218         }
2219
2220         return true;
2221 }
2222
2223 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
2224 {
2225         unsigned i;
2226         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2227         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2228         FLAC__byte buffer[4]; /* magic number is asserted below */
2229
2230         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == 4);
2231
2232         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
2233         if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2234                 return false;
2235         if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
2236                 return false;
2237
2238         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
2239         if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2240                 return false;
2241
2242         for(i = 0; i < block->num_comments; i++) {
2243                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
2244                 if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2245                         return false;
2246                 if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
2247                         return false;
2248         }
2249
2250         return true;
2251 }
2252
2253 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
2254 {
2255         unsigned i, j, len;
2256         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
2257
2258         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2259         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
2260         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);
2261         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2262
2263         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2264         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2265         if(write_cb(block->media_catalog_number, 1, len, handle) != len)
2266                 return false;
2267
2268         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2269         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2270         pack_uint64_(block->lead_in, buffer, len);
2271         if(write_cb(buffer, 1, len, handle) != len)
2272                 return false;
2273
2274         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2275         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2276         memset(buffer, 0, len);
2277         if(block->is_cd)
2278                 buffer[0] |= 0x80;
2279         if(write_cb(buffer, 1, len, handle) != len)
2280                 return false;
2281
2282         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2283         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2284         pack_uint32_(block->num_tracks, buffer, len);
2285         if(write_cb(buffer, 1, len, handle) != len)
2286                 return false;
2287
2288         for(i = 0; i < block->num_tracks; i++) {
2289                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
2290
2291                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2292                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2293                 pack_uint64_(track->offset, buffer, len);
2294                 if(write_cb(buffer, 1, len, handle) != len)
2295                         return false;
2296
2297                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2298                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2299                 pack_uint32_(track->number, buffer, len);
2300                 if(write_cb(buffer, 1, len, handle) != len)
2301                         return false;
2302
2303                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2304                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2305                 if(write_cb(track->isrc, 1, len, handle) != len)
2306                         return false;
2307
2308                 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);
2309                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2310                 memset(buffer, 0, len);
2311                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
2312                 if(write_cb(buffer, 1, len, handle) != len)
2313                         return false;
2314
2315                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2316                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2317                 pack_uint32_(track->num_indices, buffer, len);
2318                 if(write_cb(buffer, 1, len, handle) != len)
2319                         return false;
2320
2321                 for(j = 0; j < track->num_indices; j++) {
2322                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
2323
2324                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2325                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2326                         pack_uint64_(index->offset, buffer, len);
2327                         if(write_cb(buffer, 1, len, handle) != len)
2328                                 return false;
2329
2330                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2331                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2332                         pack_uint32_(index->number, buffer, len);
2333                         if(write_cb(buffer, 1, len, handle) != len)
2334                                 return false;
2335
2336                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2337                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2338                         memset(buffer, 0, len);
2339                         if(write_cb(buffer, 1, len, handle) != len)
2340                                 return false;
2341                 }
2342         }
2343
2344         return true;
2345 }
2346
2347 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2348 {
2349         if(write_cb(block->data, 1, block_length, handle) != block_length)
2350                 return false;
2351
2352         return true;
2353 }
2354
2355 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2356 {
2357         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2358                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2359                 return false;
2360         }
2361
2362         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2363                 return false;
2364
2365         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2366                 return false;
2367
2368         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2369                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2370                 return false;
2371         }
2372
2373         return read_metadata_block_header_(iterator);
2374 }
2375
2376 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2377 {
2378         FLAC__StreamMetadata *padding;
2379
2380         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2381                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2382                 return false;
2383         }
2384
2385         block->is_last = false;
2386
2387         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2388                 return false;
2389
2390         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2391                 return false;
2392
2393         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2394                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2395
2396         padding->is_last = padding_is_last;
2397         padding->length = padding_length;
2398
2399         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2400                 FLAC__metadata_object_delete(padding);
2401                 return false;
2402         }
2403
2404         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2405                 FLAC__metadata_object_delete(padding);
2406                 return false;
2407         }
2408
2409         FLAC__metadata_object_delete(padding);
2410
2411         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2412                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2413                 return false;
2414         }
2415
2416         return read_metadata_block_header_(iterator);
2417 }
2418
2419 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2420 {
2421         FILE *tempfile;
2422         char *tempfilename;
2423         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2424         long fixup_is_last_flag_offset = -1;
2425
2426         FLAC__ASSERT(0 != block || append == false);
2427
2428         if(iterator->is_last) {
2429                 if(append) {
2430                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2431                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2432                 }
2433                 else if(0 == block) {
2434                         simple_iterator_push_(iterator);
2435                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2436                                 (void)simple_iterator_pop_(iterator);
2437                                 return false;
2438                         }
2439                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2440                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2441                         if(!simple_iterator_pop_(iterator))
2442                                 return false;
2443                 }
2444         }
2445
2446         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2447                 return false;
2448
2449         if(0 != block) {
2450                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2451                         cleanup_tempfile_(&tempfile, &tempfilename);
2452                         return false;
2453                 }
2454
2455                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2456                         cleanup_tempfile_(&tempfile, &tempfilename);
2457                         return false;
2458                 }
2459         }
2460
2461         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2462                 return false;
2463
2464         if(append)
2465                 return FLAC__metadata_simple_iterator_next(iterator);
2466
2467         return true;
2468 }
2469
2470 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2471 {
2472         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2473         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2474         iterator->depth++;
2475 }
2476
2477 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2478 {
2479         FLAC__ASSERT(iterator->depth > 0);
2480         iterator->depth--;
2481         if(0 != fseek(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2482                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2483                 return false;
2484         }
2485
2486         return read_metadata_block_header_(iterator);
2487 }
2488
2489 /* return meanings:
2490  * 0: ok
2491  * 1: read error
2492  * 2: seek error
2493  * 3: not a FLAC file
2494  */
2495 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2496 {
2497         FLAC__byte buffer[4];
2498         size_t n;
2499         unsigned i;
2500
2501         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == 4);
2502
2503         /* skip any id3v2 tag */
2504         errno = 0;
2505         n = read_cb(buffer, 1, 4, handle);
2506         if(errno)
2507                 return 1;
2508         else if(n != 4)
2509                 return 3;
2510         else if(0 == memcmp(buffer, "ID3", 3)) {
2511                 unsigned tag_length = 0;
2512
2513                 /* skip to the tag length */
2514                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2515                         return 2;
2516
2517                 /* read the length */
2518                 for(i = 0; i < 4; i++) {
2519                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2520                                 return 1;
2521                         tag_length <<= 7;
2522                         tag_length |= (buffer[0] & 0x7f);
2523                 }
2524
2525                 /* skip the rest of the tag */
2526                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2527                         return 2;
2528
2529                 /* read the stream sync code */
2530                 errno = 0;
2531                 n = read_cb(buffer, 1, 4, handle);
2532                 if(errno)
2533                         return 1;
2534                 else if(n != 4)
2535                         return 3;
2536         }
2537
2538         /* check for the fLaC signature */
2539         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2540                 return 0;
2541         else
2542                 return 3;
2543 }
2544
2545 unsigned seek_to_first_metadata_block_(FILE *f)
2546 {
2547         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2548 }
2549
2550 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2551 {
2552         const long offset_end = append? iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length : iterator->offset[iterator->depth];
2553
2554         if(0 != fseek(iterator->file, 0, SEEK_SET)) {
2555                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2556                 return false;
2557         }
2558         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2559                 cleanup_tempfile_(tempfile, tempfilename);
2560                 return false;
2561         }
2562         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2563                 cleanup_tempfile_(tempfile, tempfilename);
2564                 return false;
2565         }
2566
2567         return true;
2568 }
2569
2570 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)
2571 {
2572         long save_offset = iterator->offset[iterator->depth]; /*@@@ 2G limit */
2573         FLAC__ASSERT(0 != *tempfile);
2574
2575         if(0 != fseek(iterator->file, save_offset + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length, SEEK_SET)) {
2576                 cleanup_tempfile_(tempfile, tempfilename);
2577                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2578                 return false;
2579         }
2580         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2581                 cleanup_tempfile_(tempfile, tempfilename);
2582                 return false;
2583         }
2584
2585         if(fixup_is_last_code != 0) {
2586                 /*
2587                  * if code == 1, it means a block was appended to the end so
2588                  *   we have to clear the is_last flag of the previous block
2589                  * if code == -1, it means the last block was deleted so
2590                  *   we have to set the is_last flag of the previous block
2591                  */
2592                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2593                 FLAC__byte x;
2594                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2595                         cleanup_tempfile_(tempfile, tempfilename);
2596                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2597                         return false;
2598                 }
2599                 if(fread(&x, 1, 1, *tempfile) != 1) {
2600                         cleanup_tempfile_(tempfile, tempfilename);
2601                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2602                         return false;
2603                 }
2604                 if(fixup_is_last_code > 0) {
2605                         FLAC__ASSERT(x & 0x80);
2606                         x &= 0x7f;
2607                 }
2608                 else {
2609                         FLAC__ASSERT(!(x & 0x80));
2610                         x |= 0x80;
2611                 }
2612                 if(0 != fseek(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2613                         cleanup_tempfile_(tempfile, tempfilename);
2614                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2615                         return false;
2616                 }
2617                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
2618                         cleanup_tempfile_(tempfile, tempfilename);
2619                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2620                         return false;
2621                 }
2622         }
2623
2624         (void)fclose(iterator->file);
2625
2626         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2627                 return false;
2628
2629         if(iterator->has_stats)
2630                 set_file_stats_(iterator->filename, &iterator->stats);
2631
2632         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
2633                 return false;
2634         if(backup) {
2635                 while(iterator->offset[iterator->depth] + (long)FLAC__STREAM_METADATA_HEADER_LENGTH + (long)iterator->length < save_offset)
2636                         if(!FLAC__metadata_simple_iterator_next(iterator))
2637                                 return false;
2638                 return true;
2639         }
2640         else {
2641                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2642                 FLAC__ASSERT(iterator->depth == 0);
2643                 iterator->offset[0] = save_offset;
2644                 iterator->depth++;
2645                 return simple_iterator_pop_(iterator);
2646         }
2647 }
2648
2649 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, unsigned bytes/*@@@ 4G limit*/, FLAC__Metadata_SimpleIteratorStatus *status)
2650 {
2651         FLAC__byte buffer[8192];
2652         unsigned n;
2653
2654         while(bytes > 0) {
2655                 n = min(sizeof(buffer), bytes);
2656                 if(fread(buffer, 1, n, file) != n) {
2657                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2658                         return false;
2659                 }
2660                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
2661                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2662                         return false;
2663                 }
2664                 bytes -= n;
2665         }
2666
2667         return true;
2668 }
2669
2670 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)
2671 {
2672         FLAC__byte buffer[8192];
2673         unsigned n;
2674
2675         while(bytes > 0) {
2676                 n = min(sizeof(buffer), bytes);
2677                 if(read_cb(buffer, 1, n, handle) != n) {
2678                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2679                         return false;
2680                 }
2681                 if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
2682                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2683                         return false;
2684                 }
2685                 bytes -= n;
2686         }
2687
2688         return true;
2689 }
2690
2691 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2692 {
2693         FLAC__byte buffer[8192];
2694         size_t n;
2695
2696         while(!feof(file)) {
2697                 n = fread(buffer, 1, sizeof(buffer), file);
2698                 if(n == 0 && !feof(file)) {
2699                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2700                         return false;
2701                 }
2702                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
2703                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2704                         return false;
2705                 }
2706         }
2707
2708         return true;
2709 }
2710
2711 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)
2712 {
2713         FLAC__byte buffer[8192];
2714         size_t n;
2715
2716         while(!eof_cb(handle)) {
2717                 n = read_cb(buffer, 1, sizeof(buffer), handle);
2718                 if(n == 0 && !eof_cb(handle)) {
2719                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2720                         return false;
2721                 }
2722                 if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
2723                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2724                         return false;
2725                 }
2726         }
2727
2728         return true;
2729 }
2730
2731 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2732 {
2733         static const char *tempfile_suffix = ".metadata_edit";
2734         if(0 == tempfile_path_prefix) {
2735                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
2736                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2737                         return false;
2738                 }
2739                 strcpy(*tempfilename, filename);
2740                 strcat(*tempfilename, tempfile_suffix);
2741         }
2742         else {
2743                 const char *p = strrchr(filename, '/');
2744                 if(0 == p)
2745                         p = filename;
2746                 else
2747                         p++;
2748
2749                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
2750                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2751                         return false;
2752                 }
2753                 strcpy(*tempfilename, tempfile_path_prefix);
2754                 strcat(*tempfilename, "/");
2755                 strcat(*tempfilename, p);
2756                 strcat(*tempfilename, tempfile_suffix);
2757         }
2758
2759         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
2760                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
2761                 return false;
2762         }
2763
2764         return true;
2765 }
2766
2767 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2768 {
2769         FLAC__ASSERT(0 != filename);
2770         FLAC__ASSERT(0 != tempfile);
2771         FLAC__ASSERT(0 != *tempfile);
2772         FLAC__ASSERT(0 != tempfilename);
2773         FLAC__ASSERT(0 != *tempfilename);
2774         FLAC__ASSERT(0 != status);
2775
2776         (void)fclose(*tempfile);
2777         *tempfile = 0;
2778
2779 #if defined _MSC_VER || defined __MINGW32__
2780         if(unlink(filename) < 0) {
2781                 cleanup_tempfile_(tempfile, tempfilename);
2782                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
2783                 return false;
2784         }
2785 #endif
2786
2787         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
2788         if(0 != rename(*tempfilename, filename)) {
2789                 cleanup_tempfile_(tempfile, tempfilename);
2790                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
2791                 return false;
2792         }
2793
2794         cleanup_tempfile_(tempfile, tempfilename);
2795
2796         return true;
2797 }
2798
2799 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
2800 {
2801         if(0 != *tempfile) {
2802                 (void)fclose(*tempfile);
2803                 *tempfile = 0;
2804         }
2805
2806         if(0 != *tempfilename) {
2807                 (void)unlink(*tempfilename);
2808                 free(*tempfilename);
2809                 *tempfilename = 0;
2810         }
2811 }
2812
2813 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
2814 {
2815         FLAC__ASSERT(0 != filename);
2816         FLAC__ASSERT(0 != stats);
2817         return (0 == stat(filename, stats));
2818 }
2819
2820 void set_file_stats_(const char *filename, struct stat *stats)
2821 {
2822         struct utimbuf srctime;
2823
2824         FLAC__ASSERT(0 != filename);
2825         FLAC__ASSERT(0 != stats);
2826
2827         srctime.actime = stats->st_atime;
2828         srctime.modtime = stats->st_mtime;
2829         (void)chmod(filename, stats->st_mode);
2830         (void)utime(filename, &srctime);
2831 #if !defined _MSC_VER && !defined __MINGW32__
2832         (void)chown(filename, stats->st_uid, -1);
2833         (void)chown(filename, -1, stats->st_gid);
2834 #endif
2835 }
2836
2837 /* @@@ WATCHOUT @@@
2838  * We cast FLAC__int64 to long and use fseek()/ftell() because
2839  * none of our operations on metadata is ever likely to go past
2840  * 2 gigabytes.
2841  */
2842 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
2843 {
2844         FLAC__ASSERT(offset <= 0x7fffffff);
2845         return fseek((FILE*)handle, (long)offset, whence);
2846 }
2847
2848 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
2849 {
2850         return (long)ftell((FILE*)handle);
2851 }
2852
2853 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
2854 {
2855         switch(status) {
2856                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
2857                         return FLAC__METADATA_CHAIN_STATUS_OK;
2858                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
2859                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
2860                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
2861                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
2862                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
2863                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
2864                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
2865                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
2866                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
2867                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
2868                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
2869                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
2870                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
2871                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
2872                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
2873                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
2874                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
2875                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
2876                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
2877                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
2878                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
2879                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
2880                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
2881                 default:
2882                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
2883         }
2884 }