src/libFLAC/metadata_iterators.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2001,2002,2003,2004,2005,2006  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 #if HAVE_CONFIG_H
  33 #  include <config.h>
  34 #endif
  35
  36 #include <errno.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40
  41 #if defined _MSC_VER || defined __MINGW32__
  42 #include <sys/utime.h> /* for utime() */
  43 #include <io.h> /* for chmod() */
  44 #include <sys/types.h> /* for off_t */
  45 //@@@ [2G limit] hacks for MSVC6
  46 #define fseeko fseek
  47 #define ftello ftell
  48 #else
  49 #include <sys/types.h> /* some flavors of BSD (like OS X) require this to get time_t */
  50 #include <utime.h> /* for utime() */
  51 #include <unistd.h> /* for chown(), unlink() */
  52 #endif
  53 #include <sys/stat.h> /* for stat(), maybe chmod() */
  54
  55 #include "private/metadata.h"
  56
  57 #include "FLAC/assert.h"
  58 #include "FLAC/stream_decoder.h"
  59
  60 #ifdef max
  61 #undef max
  62 #endif
  63 #define max(a,b) ((a)>(b)?(a):(b))
  64 #ifdef min
  65 #undef min
  66 #endif
  67 #define min(a,b) ((a)<(b)?(a):(b))
  68
  69
  70 /****************************************************************************
  71  *
  72  * Local function declarations
  73  *
  74  ***************************************************************************/
  75
  76 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  77 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  78 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
  79 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
  80 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
  81 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
  82
  83 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
  84 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
  85 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);
  86 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);
  87 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block);
  88 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);
  89 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);
  90 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);
  91 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);
  92 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block);
  93 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track);
  94 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block);
  95 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block);
  96 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);
  97
  98 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
  99 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
 100 static FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
 101 static FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
 102 static FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block);
 103 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);
 104 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);
 105 static FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block);
 106 static FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block);
 107 static FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block);
 108 static FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block);
 109 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);
 110
 111 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
 112 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
 113 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
 114
 115 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
 116 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
 117
 118 static unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb);
 119 static unsigned seek_to_first_metadata_block_(FILE *f);
 120
 121 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
 122 static FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, off_t fixup_is_last_flag_offset, FLAC__bool backup);
 123
 124 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status);
 125 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, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status);
 126 static FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status);
 127 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);
 128
 129 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 130 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 131 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
 132
 133 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats);
 134 static void set_file_stats_(const char *filename, struct stat *stats);
 135
 136 static int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence);
 137 static FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle);
 138
 139 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
 140
 141
 142 #ifdef FLAC__VALGRIND_TESTING
 143 static size_t local__fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
 144 {
 145         size_t ret = fwrite(ptr, size, nmemb, stream);
 146         if(!ferror(stream))
 147                 fflush(stream);
 148         return ret;
 149 }
 150 #else
 151 #define local__fwrite fwrite
 152 #endif
 153
 154 /****************************************************************************
 155  *
 156  * Level 0 implementation
 157  *
 158  ***************************************************************************/
 159
 160 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
 161 static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
 162 static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
 163
 164 typedef struct {
 165         FLAC__bool got_error;
 166         FLAC__StreamMetadata *object;
 167 } level0_client_data;
 168
 169 static FLAC__StreamMetadata *get_one_metadata_block_(const char *filename, FLAC__MetadataType type)
 170 {
 171         level0_client_data cd;
 172         FLAC__StreamDecoder *decoder;
 173
 174         FLAC__ASSERT(0 != filename);
 175
 176         cd.got_error = false;
 177         cd.object = 0;
 178
 179         decoder = FLAC__stream_decoder_new();
 180
 181         if(0 == decoder)
 182                 return 0;
 183
 184         FLAC__stream_decoder_set_md5_checking(decoder, false);
 185         FLAC__stream_decoder_set_metadata_ignore_all(decoder);
 186         FLAC__stream_decoder_set_metadata_respond(decoder, type);
 187
 188         if(FLAC__stream_decoder_init_file(decoder, filename, write_callback_, metadata_callback_, error_callback_, &cd) != FLAC__STREAM_DECODER_INIT_STATUS_OK || cd.got_error) {
 189                 FLAC__stream_decoder_finish(decoder);
 190                 FLAC__stream_decoder_delete(decoder);
 191                 return 0;
 192         }
 193
 194         if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
 195                 FLAC__stream_decoder_finish(decoder);
 196                 FLAC__stream_decoder_delete(decoder);
 197                 if(0 != cd.object)
 198                         FLAC__metadata_object_delete(cd.object);
 199                 return 0;
 200         }
 201
 202         FLAC__stream_decoder_finish(decoder);
 203         FLAC__stream_decoder_delete(decoder);
 204
 205         return cd.object;
 206 }
 207
 208 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 209 {
 210         FLAC__StreamMetadata *object;
 211
 212         FLAC__ASSERT(0 != filename);
 213         FLAC__ASSERT(0 != streaminfo);
 214
 215         object = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_STREAMINFO);
 216
 217         if (object) {
 218                 /* can just copy the contents since STREAMINFO has no internal structure */
 219                 *streaminfo = *object;
 220                 FLAC__metadata_object_delete(object);
 221                 return true;
 222         }
 223         else {
 224                 return false;
 225         }
 226 }
 227
 228 FLAC_API FLAC__bool FLAC__metadata_get_tags(const char *filename, FLAC__StreamMetadata **tags)
 229 {
 230         FLAC__ASSERT(0 != filename);
 231         FLAC__ASSERT(0 != tags);
 232
 233         *tags = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_VORBIS_COMMENT);
 234
 235         return 0 != *tags;
 236 }
 237
 238 FLAC_API FLAC__bool FLAC__metadata_get_cuesheet(const char *filename, FLAC__StreamMetadata **cuesheet)
 239 {
 240         FLAC__ASSERT(0 != filename);
 241         FLAC__ASSERT(0 != cuesheet);
 242
 243         *cuesheet = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_CUESHEET);
 244
 245         return 0 != *cuesheet;
 246 }
 247
 248 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 249 {
 250         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 251
 252         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 253 }
 254
 255 void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 256 {
 257         level0_client_data *cd = (level0_client_data *)client_data;
 258         (void)decoder;
 259
 260         /*
 261          * we assume we only get here when the one metadata block we were
 262          * looking for was passed to us
 263          */
 264         if(!cd->got_error && 0 == cd->object) {
 265                 if(0 == (cd->object = FLAC__metadata_object_clone(metadata)))
 266                         cd->got_error = true;
 267         }
 268 }
 269
 270 void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 271 {
 272         level0_client_data *cd = (level0_client_data *)client_data;
 273         (void)decoder;
 274
 275         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 276                 cd->got_error = true;
 277 }
 278
 279 FLAC_API FLAC__bool FLAC__metadata_get_picture(const char *filename, FLAC__StreamMetadata **picture, FLAC__StreamMetadata_Picture_Type type, const char *mime_type, const FLAC__byte *description, unsigned max_width, unsigned max_height, unsigned max_depth)
 280 {
 281         FLAC__Metadata_SimpleIterator *it;
 282         FLAC__uint64 max_area_seen = 0;
 283         FLAC__uint64 max_depth_seen = 0;
 284
 285         FLAC__ASSERT(0 != filename);
 286         FLAC__ASSERT(0 != picture);
 287
 288         *picture = 0;
 289
 290         it = FLAC__metadata_simple_iterator_new();
 291         if(0 == it)
 292                 return false;
 293         if(!FLAC__metadata_simple_iterator_init(it, filename, /*read_only=*/true, /*preserve_file_stats=*/true)) {
 294                 FLAC__metadata_simple_iterator_delete(it);
 295                 return false;
 296         }
 297         do {
 298                 if(FLAC__metadata_simple_iterator_get_block_type(it) == FLAC__METADATA_TYPE_PICTURE) {
 299                         FLAC__StreamMetadata *obj = FLAC__metadata_simple_iterator_get_block(it);
 300                         FLAC__uint64 area = (FLAC__uint64)obj->data.picture.width * (FLAC__uint64)obj->data.picture.height;
 301                         /* check constraints */
 302                         if(
 303                                 (type == (FLAC__StreamMetadata_Picture_Type)(-1) || type == obj->data.picture.type) &&
 304                                 (mime_type == 0 || !strcmp(mime_type, obj->data.picture.mime_type)) &&
 305                                 (description == 0 || !strcmp((const char *)description, (const char *)obj->data.picture.description)) &&
 306                                 obj->data.picture.width <= max_width &&
 307                                 obj->data.picture.height <= max_height &&
 308                                 obj->data.picture.depth <= max_depth &&
 309                                 (area > max_area_seen || (area == max_area_seen && obj->data.picture.depth > max_depth_seen))
 310                         ) {
 311                                 if(*picture)
 312                                         FLAC__metadata_object_delete(*picture);
 313                                 *picture = obj;
 314                                 max_area_seen = area;
 315                                 max_depth_seen = obj->data.picture.depth;
 316                         }
 317                         else {
 318                                 FLAC__metadata_object_delete(obj);
 319                         }
 320                 }
 321         } while(FLAC__metadata_simple_iterator_next(it));
 322
 323         FLAC__metadata_simple_iterator_delete(it);
 324
 325         return (0 != *picture);
 326 }
 327
 328
 329 /****************************************************************************
 330  *
 331  * Level 1 implementation
 332  *
 333  ***************************************************************************/
 334
 335 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 336 /* 1 for initial offset, +4 for our own personal use */
 337
 338 struct FLAC__Metadata_SimpleIterator {
 339         FILE *file;
 340         char *filename, *tempfile_path_prefix;
 341         struct stat stats;
 342         FLAC__bool has_stats;
 343         FLAC__bool is_writable;
 344         FLAC__Metadata_SimpleIteratorStatus status;
 345         off_t offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 346         off_t first_offset; /* this is the offset to the STREAMINFO block */
 347         unsigned depth;
 348         /* this is the metadata block header of the current block we are pointing to: */
 349         FLAC__bool is_last;
 350         FLAC__MetadataType type;
 351         unsigned length;
 352 };
 353
 354 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 355         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 356         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 357         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 358         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 359         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 360         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 361         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 362         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 363         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 364         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 365         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 366         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 367         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 368 };
 369
 370
 371 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 372 {
 373         FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 374
 375         if(0 != iterator) {
 376                 iterator->file = 0;
 377                 iterator->filename = 0;
 378                 iterator->tempfile_path_prefix = 0;
 379                 iterator->has_stats = false;
 380                 iterator->is_writable = false;
 381                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 382                 iterator->first_offset = iterator->offset[0] = -1;
 383                 iterator->depth = 0;
 384         }
 385
 386         return iterator;
 387 }
 388
 389 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 390 {
 391         FLAC__ASSERT(0 != iterator);
 392
 393         if(0 != iterator->file) {
 394                 fclose(iterator->file);
 395                 iterator->file = 0;
 396                 if(iterator->has_stats)
 397                         set_file_stats_(iterator->filename, &iterator->stats);
 398         }
 399         if(0 != iterator->filename) {
 400                 free(iterator->filename);
 401                 iterator->filename = 0;
 402         }
 403         if(0 != iterator->tempfile_path_prefix) {
 404                 free(iterator->tempfile_path_prefix);
 405                 iterator->tempfile_path_prefix = 0;
 406         }
 407 }
 408
 409 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 410 {
 411         FLAC__ASSERT(0 != iterator);
 412
 413         simple_iterator_free_guts_(iterator);
 414         free(iterator);
 415 }
 416
 417 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 418 {
 419         FLAC__Metadata_SimpleIteratorStatus status;
 420
 421         FLAC__ASSERT(0 != iterator);
 422
 423         status = iterator->status;
 424         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 425         return status;
 426 }
 427
 428 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
 429 {
 430         unsigned ret;
 431
 432         FLAC__ASSERT(0 != iterator);
 433
 434         if(read_only || 0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 435                 iterator->is_writable = false;
 436                 if(read_only || errno == EACCES) {
 437                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 438                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 439                                 return false;
 440                         }
 441                 }
 442                 else {
 443                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 444                         return false;
 445                 }
 446         }
 447         else {
 448                 iterator->is_writable = true;
 449         }
 450
 451         ret = seek_to_first_metadata_block_(iterator->file);
 452         switch(ret) {
 453                 case 0:
 454                         iterator->depth = 0;
 455                         iterator->first_offset = iterator->offset[iterator->depth] = ftello(iterator->file);
 456                         return read_metadata_block_header_(iterator);
 457                 case 1:
 458                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 459                         return false;
 460                 case 2:
 461                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 462                         return false;
 463                 case 3:
 464                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 465                         return false;
 466                 default:
 467                         FLAC__ASSERT(0);
 468                         return false;
 469         }
 470 }
 471
 472 #if 0
 473 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 474 /*
 475  * The 'tempfile_path_prefix' allows you to specify a directory where
 476  * tempfiles should go.  Remember that if your metadata edits cause the
 477  * FLAC file to grow, the entire file will have to be rewritten.  If
 478  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 479  * same directory as the original FLAC file.  This makes replacing the
 480  * original with the tempfile fast but requires extra space in the same
 481  * partition for the tempfile.  If space is a problem, you can pass a
 482  * directory name belonging to a different partition in
 483  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 484  * '/' as the directory separator.  A trailing slash is not needed; it
 485  * will be added automatically.
 486  */
 487 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 488 #endif
 489
 490 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)
 491 {
 492         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 493
 494         FLAC__ASSERT(0 != iterator);
 495         FLAC__ASSERT(0 != filename);
 496
 497         simple_iterator_free_guts_(iterator);
 498
 499         if(!read_only && preserve_file_stats)
 500                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 501
 502         if(0 == (iterator->filename = strdup(filename))) {
 503                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 504                 return false;
 505         }
 506         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 507                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 508                 return false;
 509         }
 510
 511         return simple_iterator_prime_input_(iterator, read_only);
 512 }
 513
 514 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 515 {
 516         FLAC__ASSERT(0 != iterator);
 517         FLAC__ASSERT(0 != iterator->file);
 518
 519         return iterator->is_writable;
 520 }
 521
 522 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 523 {
 524         FLAC__ASSERT(0 != iterator);
 525         FLAC__ASSERT(0 != iterator->file);
 526
 527         if(iterator->is_last)
 528                 return false;
 529
 530         if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
 531                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 532                 return false;
 533         }
 534
 535         iterator->offset[iterator->depth] = ftello(iterator->file);
 536
 537         return read_metadata_block_header_(iterator);
 538 }
 539
 540 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 541 {
 542         off_t this_offset;
 543
 544         FLAC__ASSERT(0 != iterator);
 545         FLAC__ASSERT(0 != iterator->file);
 546
 547         if(iterator->offset[iterator->depth] == iterator->first_offset)
 548                 return false;
 549
 550         if(0 != fseeko(iterator->file, iterator->first_offset, SEEK_SET)) {
 551                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 552                 return false;
 553         }
 554         this_offset = iterator->first_offset;
 555         if(!read_metadata_block_header_(iterator))
 556                 return false;
 557
 558         /* we ignore any error from ftello() and catch it in fseeko() */
 559         while(ftello(iterator->file) + (off_t)iterator->length < iterator->offset[iterator->depth]) {
 560                 if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
 561                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 562                         return false;
 563                 }
 564                 this_offset = ftello(iterator->file);
 565                 if(!read_metadata_block_header_(iterator))
 566                         return false;
 567         }
 568
 569         iterator->offset[iterator->depth] = this_offset;
 570
 571         return true;
 572 }
 573
 574 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 575 {
 576         FLAC__ASSERT(0 != iterator);
 577         FLAC__ASSERT(0 != iterator->file);
 578
 579         return iterator->type;
 580 }
 581
 582 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 583 {
 584         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 585
 586         FLAC__ASSERT(0 != iterator);
 587         FLAC__ASSERT(0 != iterator->file);
 588
 589         if(0 != block) {
 590                 block->is_last = iterator->is_last;
 591                 block->length = iterator->length;
 592
 593                 if(!read_metadata_block_data_(iterator, block)) {
 594                         FLAC__metadata_object_delete(block);
 595                         return 0;
 596                 }
 597
 598                 /* back up to the beginning of the block data to stay consistent */
 599                 if(0 != fseeko(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 600                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 601                         FLAC__metadata_object_delete(block);
 602                         return 0;
 603                 }
 604         }
 605         else
 606                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 607
 608         return block;
 609 }
 610
 611 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 612 {
 613         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth];)
 614         FLAC__bool ret;
 615
 616         FLAC__ASSERT(0 != iterator);
 617         FLAC__ASSERT(0 != iterator->file);
 618         FLAC__ASSERT(0 != block);
 619
 620         if(!iterator->is_writable) {
 621                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 622                 return false;
 623         }
 624
 625         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 626                 if(iterator->type != block->type) {
 627                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 628                         return false;
 629                 }
 630         }
 631
 632         block->is_last = iterator->is_last;
 633
 634         if(iterator->length == block->length)
 635                 return write_metadata_block_stationary_(iterator, block);
 636         else if(iterator->length > block->length) {
 637                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 638                         ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 639                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 640                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 641                         return ret;
 642                 }
 643                 else {
 644                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 645                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 646                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 647                         return ret;
 648                 }
 649         }
 650         else /* iterator->length < block->length */ {
 651                 unsigned padding_leftover = 0;
 652                 FLAC__bool padding_is_last = false;
 653                 if(use_padding) {
 654                         /* first see if we can even use padding */
 655                         if(iterator->is_last) {
 656                                 use_padding = false;
 657                         }
 658                         else {
 659                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 660                                 simple_iterator_push_(iterator);
 661                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 662                                         (void)simple_iterator_pop_(iterator);
 663                                         return false;
 664                                 }
 665                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 666                                         use_padding = false;
 667                                 }
 668                                 else {
 669                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 670                                                 padding_leftover = 0;
 671                                                 block->is_last = iterator->is_last;
 672                                         }
 673                                         else if(iterator->length < extra_padding_bytes_required)
 674                                                 use_padding = false;
 675                                         else {
 676                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 677                                                 padding_is_last = iterator->is_last;
 678                                                 block->is_last = false;
 679                                         }
 680                                 }
 681                                 if(!simple_iterator_pop_(iterator))
 682                                         return false;
 683                         }
 684                 }
 685                 if(use_padding) {
 686                         if(padding_leftover == 0) {
 687                                 ret = write_metadata_block_stationary_(iterator, block);
 688                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 689                                 FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 690                                 return ret;
 691                         }
 692                         else {
 693                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 694                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 695                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 696                                 FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 697                                 return ret;
 698                         }
 699                 }
 700                 else {
 701                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 702                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 703                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 704                         return ret;
 705                 }
 706         }
 707 }
 708
 709 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 710 {
 711         unsigned padding_leftover = 0;
 712         FLAC__bool padding_is_last = false;
 713
 714         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 715         FLAC__bool ret;
 716
 717         FLAC__ASSERT(0 != iterator);
 718         FLAC__ASSERT(0 != iterator->file);
 719         FLAC__ASSERT(0 != block);
 720
 721         if(!iterator->is_writable)
 722                 return false;
 723
 724         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 725                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 726                 return false;
 727         }
 728
 729         block->is_last = iterator->is_last;
 730
 731         if(use_padding) {
 732                 /* first see if we can even use padding */
 733                 if(iterator->is_last) {
 734                         use_padding = false;
 735                 }
 736                 else {
 737                         simple_iterator_push_(iterator);
 738                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 739                                 (void)simple_iterator_pop_(iterator);
 740                                 return false;
 741                         }
 742                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 743                                 use_padding = false;
 744                         }
 745                         else {
 746                                 if(iterator->length == block->length) {
 747                                         padding_leftover = 0;
 748                                         block->is_last = iterator->is_last;
 749                                 }
 750                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 751                                         use_padding = false;
 752                                 else {
 753                                         padding_leftover = iterator->length - block->length;
 754                                         padding_is_last = iterator->is_last;
 755                                         block->is_last = false;
 756                                 }
 757                         }
 758                         if(!simple_iterator_pop_(iterator))
 759                                 return false;
 760                 }
 761         }
 762         if(use_padding) {
 763                 /* move to the next block, which is suitable padding */
 764                 if(!FLAC__metadata_simple_iterator_next(iterator))
 765                         return false;
 766                 if(padding_leftover == 0) {
 767                         ret = write_metadata_block_stationary_(iterator, block);
 768                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 769                         FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 770                         return ret;
 771                 }
 772                 else {
 773                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 774                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 775                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 776                         FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 777                         return ret;
 778                 }
 779         }
 780         else {
 781                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 782                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 783                 FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 784                 return ret;
 785         }
 786 }
 787
 788 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 789 {
 790         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth];)
 791         FLAC__bool ret;
 792
 793         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 794                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 795                 return false;
 796         }
 797
 798         if(use_padding) {
 799                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 800                 if(0 == padding) {
 801                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 802                         return false;
 803                 }
 804                 padding->length = iterator->length;
 805                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 806                         FLAC__metadata_object_delete(padding);
 807                         return false;
 808                 }
 809                 FLAC__metadata_object_delete(padding);
 810                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 811                         return false;
 812                 FLAC__ASSERT(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length == debug_target_offset);
 813                 FLAC__ASSERT(ftello(iterator->file) + (off_t)iterator->length == debug_target_offset);
 814                 return true;
 815         }
 816         else {
 817                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 818                 FLAC__ASSERT(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length == debug_target_offset);
 819                 FLAC__ASSERT(ftello(iterator->file) + (off_t)iterator->length == debug_target_offset);
 820                 return ret;
 821         }
 822 }
 823
 824
 825
 826 /****************************************************************************
 827  *
 828  * Level 2 implementation
 829  *
 830  ***************************************************************************/
 831
 832
 833 typedef struct FLAC__Metadata_Node {
 834         FLAC__StreamMetadata *data;
 835         struct FLAC__Metadata_Node *prev, *next;
 836 } FLAC__Metadata_Node;
 837
 838 struct FLAC__Metadata_Chain {
 839         char *filename; /* will be NULL if using callbacks */
 840         FLAC__Metadata_Node *head;
 841         FLAC__Metadata_Node *tail;
 842         unsigned nodes;
 843         FLAC__Metadata_ChainStatus status;
 844         off_t first_offset, last_offset;
 845         /*
 846          * This is the length of the chain initially read from the FLAC file.
 847          * it is used to compare against the current length to decide whether
 848          * or not the whole file has to be rewritten.
 849          */
 850         off_t initial_length;
 851 };
 852
 853 struct FLAC__Metadata_Iterator {
 854         FLAC__Metadata_Chain *chain;
 855         FLAC__Metadata_Node *current;
 856 };
 857
 858 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 859         "FLAC__METADATA_CHAIN_STATUS_OK",
 860         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 861         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 862         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 863         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 864         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 865         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 866         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 867         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 868         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 869         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 870         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 871         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
 872         "FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
 873         "FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
 874         "FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
 875 };
 876
 877
 878 static FLAC__Metadata_Node *node_new_()
 879 {
 880         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 881 }
 882
 883 static void node_delete_(FLAC__Metadata_Node *node)
 884 {
 885         FLAC__ASSERT(0 != node);
 886         if(0 != node->data)
 887                 FLAC__metadata_object_delete(node->data);
 888         free(node);
 889 }
 890
 891 static void chain_init_(FLAC__Metadata_Chain *chain)
 892 {
 893         FLAC__ASSERT(0 != chain);
 894
 895         chain->filename = 0;
 896         chain->head = chain->tail = 0;
 897         chain->nodes = 0;
 898         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 899         chain->initial_length = 0;
 900 }
 901
 902 static void chain_clear_(FLAC__Metadata_Chain *chain)
 903 {
 904         FLAC__Metadata_Node *node, *next;
 905
 906         FLAC__ASSERT(0 != chain);
 907
 908         for(node = chain->head; node; ) {
 909                 next = node->next;
 910                 node_delete_(node);
 911                 node = next;
 912         }
 913
 914         if(0 != chain->filename)
 915                 free(chain->filename);
 916
 917         chain_init_(chain);
 918 }
 919
 920 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 921 {
 922         FLAC__ASSERT(0 != chain);
 923         FLAC__ASSERT(0 != node);
 924         FLAC__ASSERT(0 != node->data);
 925
 926         node->next = node->prev = 0;
 927         node->data->is_last = true;
 928         if(0 != chain->tail)
 929                 chain->tail->data->is_last = false;
 930
 931         if(0 == chain->head)
 932                 chain->head = node;
 933         else {
 934                 FLAC__ASSERT(0 != chain->tail);
 935                 chain->tail->next = node;
 936                 node->prev = chain->tail;
 937         }
 938         chain->tail = node;
 939         chain->nodes++;
 940 }
 941
 942 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 943 {
 944         FLAC__ASSERT(0 != chain);
 945         FLAC__ASSERT(0 != node);
 946
 947         if(node == chain->head)
 948                 chain->head = node->next;
 949         else
 950                 node->prev->next = node->next;
 951
 952         if(node == chain->tail)
 953                 chain->tail = node->prev;
 954         else
 955                 node->next->prev = node->prev;
 956
 957         if(0 != chain->tail)
 958                 chain->tail->data->is_last = true;
 959
 960         chain->nodes--;
 961 }
 962
 963 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 964 {
 965         chain_remove_node_(chain, node);
 966         node_delete_(node);
 967 }
 968
 969 static off_t chain_calculate_length_(FLAC__Metadata_Chain *chain)
 970 {
 971         const FLAC__Metadata_Node *node;
 972         off_t length = 0;
 973         for(node = chain->head; node; node = node->next)
 974                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 975         return length;
 976 }
 977
 978 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 979 {
 980         FLAC__ASSERT(0 != node);
 981         FLAC__ASSERT(0 != node->data);
 982         FLAC__ASSERT(0 != iterator);
 983         FLAC__ASSERT(0 != iterator->current);
 984         FLAC__ASSERT(0 != iterator->chain);
 985         FLAC__ASSERT(0 != iterator->chain->head);
 986         FLAC__ASSERT(0 != iterator->chain->tail);
 987
 988         node->data->is_last = false;
 989
 990         node->prev = iterator->current->prev;
 991         node->next = iterator->current;
 992
 993         if(0 == node->prev)
 994                 iterator->chain->head = node;
 995         else
 996                 node->prev->next = node;
 997
 998         iterator->current->prev = node;
 999
1000         iterator->chain->nodes++;
1001 }
1002
1003 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
1004 {
1005         FLAC__ASSERT(0 != node);
1006         FLAC__ASSERT(0 != node->data);
1007         FLAC__ASSERT(0 != iterator);
1008         FLAC__ASSERT(0 != iterator->current);
1009         FLAC__ASSERT(0 != iterator->chain);
1010         FLAC__ASSERT(0 != iterator->chain->head);
1011         FLAC__ASSERT(0 != iterator->chain->tail);
1012
1013         iterator->current->data->is_last = false;
1014
1015         node->prev = iterator->current;
1016         node->next = iterator->current->next;
1017
1018         if(0 == node->next)
1019                 iterator->chain->tail = node;
1020         else
1021                 node->next->prev = node;
1022
1023         node->prev->next = node;
1024
1025         iterator->chain->tail->data->is_last = true;
1026
1027         iterator->chain->nodes++;
1028 }
1029
1030 /* return true iff node and node->next are both padding */
1031 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
1032 {
1033         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
1034                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
1035                 node->data->length += growth;
1036
1037                 chain_delete_node_(chain, node->next);
1038                 return true;
1039         }
1040         else
1041                 return false;
1042 }
1043
1044 /* Returns the new length of the chain, or 0 if there was an error. */
1045 /* WATCHOUT: This can get called multiple times before a write, so
1046  * it should still work when this happens.
1047  */
1048 /* WATCHOUT: Make sure to also update the logic in
1049  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
1050  */
1051 static off_t chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1052 {
1053         off_t current_length = chain_calculate_length_(chain);
1054
1055         if(use_padding) {
1056                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1057                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1058                         const off_t delta = chain->initial_length - current_length;
1059                         chain->tail->data->length += delta;
1060                         current_length += delta;
1061                         FLAC__ASSERT(current_length == chain->initial_length);
1062                 }
1063                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1064                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1065                         FLAC__StreamMetadata *padding;
1066                         FLAC__Metadata_Node *node;
1067                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1068                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1069                                 return 0;
1070                         }
1071                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1072                         if(0 == (node = node_new_())) {
1073                                 FLAC__metadata_object_delete(padding);
1074                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1075                                 return 0;
1076                         }
1077                         node->data = padding;
1078                         chain_append_node_(chain, node);
1079                         current_length = chain_calculate_length_(chain);
1080                         FLAC__ASSERT(current_length == chain->initial_length);
1081                 }
1082                 /* 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 */
1083                 else if(current_length > chain->initial_length) {
1084                         const off_t delta = current_length - chain->initial_length;
1085                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1086                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1087                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1088                                         chain_delete_node_(chain, chain->tail);
1089                                         current_length = chain_calculate_length_(chain);
1090                                         FLAC__ASSERT(current_length == chain->initial_length);
1091                                 }
1092                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1093                                 else if((off_t)chain->tail->data->length >= delta) {
1094                                         chain->tail->data->length -= delta;
1095                                         current_length -= delta;
1096                                         FLAC__ASSERT(current_length == chain->initial_length);
1097                                 }
1098                         }
1099                 }
1100         }
1101
1102         return current_length;
1103 }
1104
1105 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)
1106 {
1107         FLAC__Metadata_Node *node;
1108
1109         FLAC__ASSERT(0 != chain);
1110
1111         /* we assume we're already at the beginning of the file */
1112
1113         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
1114                 case 0:
1115                         break;
1116                 case 1:
1117                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1118                         return false;
1119                 case 2:
1120                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1121                         return false;
1122                 case 3:
1123                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
1124                         return false;
1125                 default:
1126                         FLAC__ASSERT(0);
1127                         return false;
1128         }
1129
1130         {
1131                 FLAC__int64 pos = tell_cb(handle);
1132                 if(pos < 0) {
1133                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1134                         return false;
1135                 }
1136                 chain->first_offset = (off_t)pos;
1137         }
1138
1139         {
1140                 FLAC__bool is_last;
1141                 FLAC__MetadataType type;
1142                 unsigned length;
1143
1144                 do {
1145                         node = node_new_();
1146                         if(0 == node) {
1147                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1148                                 return false;
1149                         }
1150
1151                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
1152                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1153                                 return false;
1154                         }
1155
1156                         node->data = FLAC__metadata_object_new(type);
1157                         if(0 == node->data) {
1158                                 node_delete_(node);
1159                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1160                                 return false;
1161                         }
1162
1163                         node->data->is_last = is_last;
1164                         node->data->length = length;
1165
1166                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
1167                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1168                                 node_delete_(node);
1169                                 return false;
1170                         }
1171                         chain_append_node_(chain, node);
1172                 } while(!is_last);
1173         }
1174
1175         {
1176                 FLAC__int64 pos = tell_cb(handle);
1177                 if(pos < 0) {
1178                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1179                         return false;
1180                 }
1181                 chain->last_offset = (off_t)pos;
1182         }
1183
1184         chain->initial_length = chain_calculate_length_(chain);
1185
1186         return true;
1187 }
1188
1189 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)
1190 {
1191         FLAC__Metadata_Node *node;
1192
1193         FLAC__ASSERT(0 != chain);
1194         FLAC__ASSERT(0 != chain->head);
1195
1196         if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
1197                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1198                 return false;
1199         }
1200
1201         for(node = chain->head; node; node = node->next) {
1202                 if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
1203                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1204                         return false;
1205                 }
1206                 if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
1207                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1208                         return false;
1209                 }
1210         }
1211
1212         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1213
1214         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1215         return true;
1216 }
1217
1218 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
1219 {
1220         FILE *file;
1221         FLAC__bool ret;
1222
1223         FLAC__ASSERT(0 != chain->filename);
1224
1225         if(0 == (file = fopen(chain->filename, "r+b"))) {
1226                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1227                 return false;
1228         }
1229
1230         /* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
1231         ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
1232
1233         fclose(file);
1234
1235         return ret;
1236 }
1237
1238 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1239 {
1240         FILE *f, *tempfile;
1241         char *tempfilename;
1242         FLAC__Metadata_SimpleIteratorStatus status;
1243         const FLAC__Metadata_Node *node;
1244
1245         FLAC__ASSERT(0 != chain);
1246         FLAC__ASSERT(0 != chain->filename);
1247         FLAC__ASSERT(0 != chain->head);
1248
1249         /* copy the file prefix (data up to first metadata block */
1250         if(0 == (f = fopen(chain->filename, "rb"))) {
1251                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1252                 return false;
1253         }
1254         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1255                 chain->status = get_equivalent_status_(status);
1256                 cleanup_tempfile_(&tempfile, &tempfilename);
1257                 return false;
1258         }
1259         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1260                 chain->status = get_equivalent_status_(status);
1261                 cleanup_tempfile_(&tempfile, &tempfilename);
1262                 return false;
1263         }
1264
1265         /* write the metadata */
1266         for(node = chain->head; node; node = node->next) {
1267                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1268                         chain->status = get_equivalent_status_(status);
1269                         return false;
1270                 }
1271                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1272                         chain->status = get_equivalent_status_(status);
1273                         return false;
1274                 }
1275         }
1276         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1277
1278         /* copy the file postfix (everything after the metadata) */
1279         if(0 != fseeko(f, chain->last_offset, SEEK_SET)) {
1280                 cleanup_tempfile_(&tempfile, &tempfilename);
1281                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1282                 return false;
1283         }
1284         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1285                 cleanup_tempfile_(&tempfile, &tempfilename);
1286                 chain->status = get_equivalent_status_(status);
1287                 return false;
1288         }
1289
1290         /* move the tempfile on top of the original */
1291         (void)fclose(f);
1292         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1293                 return false;
1294
1295         return true;
1296 }
1297
1298 /* assumes 'handle' is already at beginning of file */
1299 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)
1300 {
1301         FLAC__Metadata_SimpleIteratorStatus status;
1302         const FLAC__Metadata_Node *node;
1303
1304         FLAC__ASSERT(0 != chain);
1305         FLAC__ASSERT(0 == chain->filename);
1306         FLAC__ASSERT(0 != chain->head);
1307
1308         /* copy the file prefix (data up to first metadata block */
1309         if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
1310                 chain->status = get_equivalent_status_(status);
1311                 return false;
1312         }
1313
1314         /* write the metadata */
1315         for(node = chain->head; node; node = node->next) {
1316                 if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
1317                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1318                         return false;
1319                 }
1320                 if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
1321                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1322                         return false;
1323                 }
1324         }
1325         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1326
1327         /* copy the file postfix (everything after the metadata) */
1328         if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
1329                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1330                 return false;
1331         }
1332         if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
1333                 chain->status = get_equivalent_status_(status);
1334                 return false;
1335         }
1336
1337         return true;
1338 }
1339
1340 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1341 {
1342         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1343
1344         if(0 != chain)
1345                 chain_init_(chain);
1346
1347         return chain;
1348 }
1349
1350 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1351 {
1352         FLAC__ASSERT(0 != chain);
1353
1354         chain_clear_(chain);
1355
1356         free(chain);
1357 }
1358
1359 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1360 {
1361         FLAC__Metadata_ChainStatus status;
1362
1363         FLAC__ASSERT(0 != chain);
1364
1365         status = chain->status;
1366         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1367         return status;
1368 }
1369
1370 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1371 {
1372         FILE *file;
1373         FLAC__bool ret;
1374
1375         FLAC__ASSERT(0 != chain);
1376         FLAC__ASSERT(0 != filename);
1377
1378         chain_clear_(chain);
1379
1380         if(0 == (chain->filename = strdup(filename))) {
1381                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1382                 return false;
1383         }
1384
1385         if(0 == (file = fopen(filename, "rb"))) {
1386                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1387                 return false;
1388         }
1389
1390         /* chain_read_cb_() sets chain->status for us */
1391         ret = chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_);
1392
1393         fclose(file);
1394
1395         return ret;
1396 }
1397
1398 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1399 {
1400         FLAC__ASSERT(0 != chain);
1401
1402         chain_clear_(chain);
1403
1404         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
1405                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1406                 return false;
1407         }
1408
1409         /* rewind */
1410         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1411                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1412                 return false;
1413         }
1414
1415         if(!chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell))
1416                 return false; /* chain->status is already set by chain_read_cb_ */
1417
1418         return true;
1419 }
1420
1421 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1422 {
1423         /* This does all the same checks that are in chain_prepare_for_write_()
1424          * but doesn't actually alter the chain.  Make sure to update the logic
1425          * here if chain_prepare_for_write_() changes.
1426          */
1427         const off_t current_length = chain_calculate_length_(chain);
1428
1429         FLAC__ASSERT(0 != chain);
1430
1431         if(use_padding) {
1432                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1433                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING)
1434                         return false;
1435                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1436                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length)
1437                         return false;
1438                 /* 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 */
1439                 else if(current_length > chain->initial_length) {
1440                         const off_t delta = current_length - chain->initial_length;
1441                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1442                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1443                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta)
1444                                         return false;
1445                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1446                                 else if((off_t)chain->tail->data->length >= delta)
1447                                         return false;
1448                         }
1449                 }
1450         }
1451
1452         return (current_length != chain->initial_length);
1453 }
1454
1455 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1456 {
1457         struct stat stats;
1458         const char *tempfile_path_prefix = 0;
1459         off_t current_length;
1460
1461         FLAC__ASSERT(0 != chain);
1462
1463         if (0 == chain->filename) {
1464                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1465                 return false;
1466         }
1467
1468         current_length = chain_prepare_for_write_(chain, use_padding);
1469
1470         /* a return value of 0 means there was an error; chain->status is already set */
1471         if (0 == current_length)
1472                 return false;
1473
1474         if(preserve_file_stats)
1475                 get_file_stats_(chain->filename, &stats);
1476
1477         if(current_length == chain->initial_length) {
1478                 if(!chain_rewrite_metadata_in_place_(chain))
1479                         return false;
1480         }
1481         else {
1482                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1483                         return false;
1484
1485                 /* recompute lengths and offsets */
1486                 {
1487                         const FLAC__Metadata_Node *node;
1488                         chain->initial_length = current_length;
1489                         chain->last_offset = chain->first_offset;
1490                         for(node = chain->head; node; node = node->next)
1491                                 chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1492                 }
1493         }
1494
1495         if(preserve_file_stats)
1496                 set_file_stats_(chain->filename, &stats);
1497
1498         return true;
1499 }
1500
1501 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1502 {
1503         off_t current_length;
1504
1505         FLAC__ASSERT(0 != chain);
1506
1507         if (0 != chain->filename) {
1508                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1509                 return false;
1510         }
1511
1512         if (0 == callbacks.write || 0 == callbacks.seek) {
1513                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1514                 return false;
1515         }
1516
1517         if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1518                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1519                 return false;
1520         }
1521
1522         current_length = chain_prepare_for_write_(chain, use_padding);
1523
1524         /* a return value of 0 means there was an error; chain->status is already set */
1525         if (0 == current_length)
1526                 return false;
1527
1528         FLAC__ASSERT(current_length == chain->initial_length);
1529
1530         return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
1531 }
1532
1533 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)
1534 {
1535         off_t current_length;
1536
1537         FLAC__ASSERT(0 != chain);
1538
1539         if (0 != chain->filename) {
1540                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1541                 return false;
1542         }
1543
1544         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
1545                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1546                 return false;
1547         }
1548         if (0 == temp_callbacks.write) {
1549                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1550                 return false;
1551         }
1552
1553         if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1554                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1555                 return false;
1556         }
1557
1558         current_length = chain_prepare_for_write_(chain, use_padding);
1559
1560         /* a return value of 0 means there was an error; chain->status is already set */
1561         if (0 == current_length)
1562                 return false;
1563
1564         FLAC__ASSERT(current_length != chain->initial_length);
1565
1566         /* rewind */
1567         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1568                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1569                 return false;
1570         }
1571
1572         if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
1573                 return false;
1574
1575         /* recompute lengths and offsets */
1576         {
1577                 const FLAC__Metadata_Node *node;
1578                 chain->initial_length = current_length;
1579                 chain->last_offset = chain->first_offset;
1580                 for(node = chain->head; node; node = node->next)
1581                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1582         }
1583
1584         return true;
1585 }
1586
1587 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1588 {
1589         FLAC__Metadata_Node *node;
1590
1591         FLAC__ASSERT(0 != chain);
1592
1593         for(node = chain->head; node; ) {
1594                 if(!chain_merge_adjacent_padding_(chain, node))
1595                         node = node->next;
1596         }
1597 }
1598
1599 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1600 {
1601         FLAC__Metadata_Node *node, *save;
1602         unsigned i;
1603
1604         FLAC__ASSERT(0 != chain);
1605
1606         /*
1607          * Don't try and be too smart... this simple algo is good enough for
1608          * the small number of nodes that we deal with.
1609          */
1610         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1611                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1612                         save = node->next;
1613                         chain_remove_node_(chain, node);
1614                         chain_append_node_(chain, node);
1615                         node = save;
1616                 }
1617                 else {
1618                         node = node->next;
1619                 }
1620         }
1621
1622         FLAC__metadata_chain_merge_padding(chain);
1623 }
1624
1625
1626 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1627 {
1628         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1629
1630         /* calloc() implies:
1631                 iterator->current = 0;
1632                 iterator->chain = 0;
1633         */
1634
1635         return iterator;
1636 }
1637
1638 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1639 {
1640         FLAC__ASSERT(0 != iterator);
1641
1642         free(iterator);
1643 }
1644
1645 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1646 {
1647         FLAC__ASSERT(0 != iterator);
1648         FLAC__ASSERT(0 != chain);
1649         FLAC__ASSERT(0 != chain->head);
1650
1651         iterator->chain = chain;
1652         iterator->current = chain->head;
1653 }
1654
1655 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1656 {
1657         FLAC__ASSERT(0 != iterator);
1658
1659         if(0 == iterator->current || 0 == iterator->current->next)
1660                 return false;
1661
1662         iterator->current = iterator->current->next;
1663         return true;
1664 }
1665
1666 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1667 {
1668         FLAC__ASSERT(0 != iterator);
1669
1670         if(0 == iterator->current || 0 == iterator->current->prev)
1671                 return false;
1672
1673         iterator->current = iterator->current->prev;
1674         return true;
1675 }
1676
1677 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1678 {
1679         FLAC__ASSERT(0 != iterator);
1680         FLAC__ASSERT(0 != iterator->current);
1681         FLAC__ASSERT(0 != iterator->current->data);
1682
1683         return iterator->current->data->type;
1684 }
1685
1686 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1687 {
1688         FLAC__ASSERT(0 != iterator);
1689         FLAC__ASSERT(0 != iterator->current);
1690
1691         return iterator->current->data;
1692 }
1693
1694 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1695 {
1696         FLAC__ASSERT(0 != iterator);
1697         FLAC__ASSERT(0 != block);
1698         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1699 }
1700
1701 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1702 {
1703         FLAC__Metadata_Node *save;
1704
1705         FLAC__ASSERT(0 != iterator);
1706         FLAC__ASSERT(0 != iterator->current);
1707
1708         if(0 == iterator->current->prev) {
1709                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1710                 return false;
1711         }
1712
1713         save = iterator->current->prev;
1714
1715         if(replace_with_padding) {
1716                 FLAC__metadata_object_delete_data(iterator->current->data);
1717                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1718         }
1719         else {
1720                 chain_delete_node_(iterator->chain, iterator->current);
1721         }
1722
1723         iterator->current = save;
1724         return true;
1725 }
1726
1727 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1728 {
1729         FLAC__Metadata_Node *node;
1730
1731         FLAC__ASSERT(0 != iterator);
1732         FLAC__ASSERT(0 != iterator->current);
1733         FLAC__ASSERT(0 != block);
1734
1735         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1736                 return false;
1737
1738         if(0 == iterator->current->prev) {
1739                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1740                 return false;
1741         }
1742
1743         if(0 == (node = node_new_()))
1744                 return false;
1745
1746         node->data = block;
1747         iterator_insert_node_(iterator, node);
1748         iterator->current = node;
1749         return true;
1750 }
1751
1752 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1753 {
1754         FLAC__Metadata_Node *node;
1755
1756         FLAC__ASSERT(0 != iterator);
1757         FLAC__ASSERT(0 != iterator->current);
1758         FLAC__ASSERT(0 != block);
1759
1760         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1761                 return false;
1762
1763         if(0 == (node = node_new_()))
1764                 return false;
1765
1766         node->data = block;
1767         iterator_insert_node_after_(iterator, node);
1768         iterator->current = node;
1769         return true;
1770 }
1771
1772
1773 /****************************************************************************
1774  *
1775  * Local function definitions
1776  *
1777  ***************************************************************************/
1778
1779 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1780 {
1781         unsigned i;
1782
1783         b += bytes;
1784
1785         for(i = 0; i < bytes; i++) {
1786                 *(--b) = (FLAC__byte)(val & 0xff);
1787                 val >>= 8;
1788         }
1789 }
1790
1791 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1792 {
1793         unsigned i;
1794
1795         for(i = 0; i < bytes; i++) {
1796                 *(b++) = (FLAC__byte)(val & 0xff);
1797                 val >>= 8;
1798         }
1799 }
1800
1801 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1802 {
1803         unsigned i;
1804
1805         b += bytes;
1806
1807         for(i = 0; i < bytes; i++) {
1808                 *(--b) = (FLAC__byte)(val & 0xff);
1809                 val >>= 8;
1810         }
1811 }
1812
1813 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1814 {
1815         FLAC__uint32 ret = 0;
1816         unsigned i;
1817
1818         for(i = 0; i < bytes; i++)
1819                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1820
1821         return ret;
1822 }
1823
1824 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1825 {
1826         FLAC__uint32 ret = 0;
1827         unsigned i;
1828
1829         b += bytes;
1830
1831         for(i = 0; i < bytes; i++)
1832                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1833
1834         return ret;
1835 }
1836
1837 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1838 {
1839         FLAC__uint64 ret = 0;
1840         unsigned i;
1841
1842         for(i = 0; i < bytes; i++)
1843                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1844
1845         return ret;
1846 }
1847
1848 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1849 {
1850         FLAC__ASSERT(0 != iterator);
1851         FLAC__ASSERT(0 != iterator->file);
1852
1853         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1854                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1855                 return false;
1856         }
1857
1858         return true;
1859 }
1860
1861 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1862 {
1863         FLAC__ASSERT(0 != iterator);
1864         FLAC__ASSERT(0 != iterator->file);
1865
1866         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
1867
1868         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1869 }
1870
1871 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
1872 {
1873         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1874
1875         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
1876                 return false;
1877
1878         *is_last = raw_header[0] & 0x80? true : false;
1879         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1880         *length = unpack_uint32_(raw_header + 1, 3);
1881
1882         /* Note that we don't check:
1883          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
1884          * we just will read in an opaque block
1885          */
1886
1887         return true;
1888 }
1889
1890 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
1891 {
1892         switch(block->type) {
1893                 case FLAC__METADATA_TYPE_STREAMINFO:
1894                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
1895                 case FLAC__METADATA_TYPE_PADDING:
1896                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
1897                 case FLAC__METADATA_TYPE_APPLICATION:
1898                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
1899                 case FLAC__METADATA_TYPE_SEEKTABLE:
1900                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
1901                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1902                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
1903                 case FLAC__METADATA_TYPE_CUESHEET:
1904                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
1905                 case FLAC__METADATA_TYPE_PICTURE:
1906                         return read_metadata_block_data_picture_cb_(handle, read_cb, &block->data.picture);
1907                 default:
1908                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
1909         }
1910 }
1911
1912 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
1913 {
1914         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1915
1916         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1917                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1918
1919         b = buffer;
1920
1921         /* we are using hardcoded numbers for simplicity but we should
1922          * probably eventually write a bit-level unpacker and use the
1923          * _STREAMINFO_ constants.
1924          */
1925         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1926         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1927         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1928         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1929         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1930         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1931         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1932         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1933         memcpy(block->md5sum, b+8, 16);
1934
1935         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1936 }
1937
1938 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1939 {
1940         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1941
1942         if(0 != seek_cb(handle, block_length, SEEK_CUR))
1943                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1944
1945         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1946 }
1947
1948 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
1949 {
1950         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1951
1952         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
1953                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1954
1955         block_length -= id_bytes;
1956
1957         if(block_length == 0) {
1958                 block->data = 0;
1959         }
1960         else {
1961                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1962                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1963
1964                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1965                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1966         }
1967
1968         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1969 }
1970
1971 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1972 {
1973         unsigned i;
1974         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1975
1976         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1977
1978         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1979
1980         if(block->num_points == 0)
1981                 block->points = 0;
1982         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1983                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1984
1985         for(i = 0; i < block->num_points; i++) {
1986                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1987                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1988                 /* some MAGIC NUMBERs here */
1989                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1990                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1991                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1992         }
1993
1994         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1995 }
1996
1997 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
1998 {
1999         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2000         FLAC__byte buffer[4]; /* magic number is asserted below */
2001
2002         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == sizeof(buffer));
2003
2004         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2005                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2006         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
2007
2008         if(0 != entry->entry)
2009                 free(entry->entry);
2010
2011         if(entry->length == 0) {
2012                 entry->entry = 0;
2013         }
2014         else {
2015                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length+1)))
2016                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2017
2018                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
2019                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2020
2021                 entry->entry[entry->length] = '\0';
2022         }
2023
2024         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2025 }
2026
2027 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
2028 {
2029         unsigned i;
2030         FLAC__Metadata_SimpleIteratorStatus status;
2031         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2032         FLAC__byte buffer[4]; /* magic number is asserted below */
2033
2034         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == sizeof(buffer));
2035
2036         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
2037                 return status;
2038
2039         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2040                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2041         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
2042
2043         if(block->num_comments == 0) {
2044                 block->comments = 0;
2045         }
2046         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
2047                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2048
2049         for(i = 0; i < block->num_comments; i++) {
2050                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
2051                         return status;
2052         }
2053
2054         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2055 }
2056
2057 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
2058 {
2059         unsigned i, len;
2060         FLAC__byte buffer[32]; /* asserted below that this is big enough */
2061
2062         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2063         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2064         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);
2065
2066         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2067         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2068         if(read_cb(buffer, 1, len, handle) != len)
2069                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2070         track->offset = unpack_uint64_(buffer, len);
2071
2072         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2073         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2074         if(read_cb(buffer, 1, len, handle) != len)
2075                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2076         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
2077
2078         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2079         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2080         if(read_cb(track->isrc, 1, len, handle) != len)
2081                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2082
2083         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);
2084         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2085         if(read_cb(buffer, 1, len, handle) != len)
2086                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2087         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
2088         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
2089         track->type = buffer[0] >> 7;
2090         track->pre_emphasis = (buffer[0] >> 6) & 1;
2091
2092         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2093         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2094         if(read_cb(buffer, 1, len, handle) != len)
2095                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2096         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
2097
2098         if(track->num_indices == 0) {
2099                 track->indices = 0;
2100         }
2101         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
2102                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2103
2104         for(i = 0; i < track->num_indices; i++) {
2105                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2106                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2107                 if(read_cb(buffer, 1, len, handle) != len)
2108                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2109                 track->indices[i].offset = unpack_uint64_(buffer, len);
2110
2111                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2112                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2113                 if(read_cb(buffer, 1, len, handle) != len)
2114                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2115                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
2116
2117                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2118                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2119                 if(read_cb(buffer, 1, len, handle) != len)
2120                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2121         }
2122
2123         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2124 }
2125
2126 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
2127 {
2128         unsigned i, len;
2129         FLAC__Metadata_SimpleIteratorStatus status;
2130         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
2131
2132         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
2133         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
2134
2135         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2136         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2137         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
2138                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2139
2140         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2141         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2142         if(read_cb(buffer, 1, len, handle) != len)
2143                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2144         block->lead_in = unpack_uint64_(buffer, len);
2145
2146         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2147         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2148         if(read_cb(buffer, 1, len, handle) != len)
2149                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2150         block->is_cd = buffer[0]&0x80? true : false;
2151
2152         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2153         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2154         if(read_cb(buffer, 1, len, handle) != len)
2155                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2156         block->num_tracks = unpack_uint32_(buffer, len);
2157
2158         if(block->num_tracks == 0) {
2159                 block->tracks = 0;
2160         }
2161         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
2162                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2163
2164         for(i = 0; i < block->num_tracks; i++) {
2165                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
2166                         return status;
2167         }
2168
2169         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2170 }
2171
2172 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cstring_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__byte **data, FLAC__uint32 *length, FLAC__uint32 length_len)
2173 {
2174         FLAC__byte buffer[sizeof(FLAC__uint32)];
2175
2176         FLAC__ASSERT(0 != data);
2177         FLAC__ASSERT(length_len%8 == 0);
2178
2179         length_len /= 8; /* convert to bytes */
2180
2181         FLAC__ASSERT(sizeof(buffer) >= length_len);
2182
2183         if(read_cb(buffer, 1, length_len, handle) != length_len)
2184                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2185         *length = unpack_uint32_(buffer, length_len);
2186
2187         if(0 != *data)
2188                 free(*data);
2189
2190         if(0 == (*data = (FLAC__byte*)malloc(*length+1)))
2191                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2192
2193         if(*length > 0) {
2194                 if(read_cb(*data, 1, *length, handle) != *length)
2195                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2196         }
2197
2198         (*data)[*length] = '\0';
2199
2200         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2201 }
2202
2203 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block)
2204 {
2205         FLAC__Metadata_SimpleIteratorStatus status;
2206         FLAC__byte buffer[4]; /* asserted below that this is big enough */
2207         FLAC__uint32 len;
2208
2209         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2210         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2211         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2212         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2213
2214         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_TYPE_LEN % 8 == 0);
2215         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN / 8;
2216         if(read_cb(buffer, 1, len, handle) != len)
2217                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2218         block->type = (FLAC__StreamMetadata_Picture_Type)unpack_uint32_(buffer, len);
2219
2220         if((status = read_metadata_block_data_picture_cstring_cb_(handle, read_cb, (FLAC__byte**)(&(block->mime_type)), &len, FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN)) != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK)
2221                 return status;
2222
2223         if((status = read_metadata_block_data_picture_cstring_cb_(handle, read_cb, &(block->description), &len, FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN)) != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK)
2224                 return status;
2225
2226         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN % 8 == 0);
2227         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN / 8;
2228         if(read_cb(buffer, 1, len, handle) != len)
2229                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2230         block->width = unpack_uint32_(buffer, len);
2231
2232         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN % 8 == 0);
2233         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN / 8;
2234         if(read_cb(buffer, 1, len, handle) != len)
2235                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2236         block->height = unpack_uint32_(buffer, len);
2237
2238         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN % 8 == 0);
2239         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN / 8;
2240         if(read_cb(buffer, 1, len, handle) != len)
2241                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2242         block->depth = unpack_uint32_(buffer, len);
2243
2244         /* for convenience we use read_metadata_block_data_picture_cstring_cb_() even though it adds an extra terminating NUL we don't use */
2245         if((status = read_metadata_block_data_picture_cstring_cb_(handle, read_cb, &(block->data), &(block->data_length), FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN)) != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK)
2246                 return status;
2247
2248         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2249 }
2250
2251 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2252 {
2253         if(block_length == 0) {
2254                 block->data = 0;
2255         }
2256         else {
2257                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2258                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2259
2260                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2261                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2262         }
2263
2264         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2265 }
2266
2267 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2268 {
2269         FLAC__ASSERT(0 != file);
2270         FLAC__ASSERT(0 != status);
2271
2272         if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2273                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2274                 return false;
2275         }
2276
2277         return true;
2278 }
2279
2280 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2281 {
2282         FLAC__ASSERT(0 != file);
2283         FLAC__ASSERT(0 != status);
2284
2285         if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2286                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2287                 return true;
2288         }
2289         else {
2290                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2291                 return false;
2292         }
2293 }
2294
2295 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2296 {
2297         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
2298
2299         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
2300
2301         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
2302         pack_uint32_(block->length, buffer + 1, 3);
2303
2304         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2305                 return false;
2306
2307         return true;
2308 }
2309
2310 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2311 {
2312         FLAC__ASSERT(0 != block);
2313
2314         switch(block->type) {
2315                 case FLAC__METADATA_TYPE_STREAMINFO:
2316                         return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
2317                 case FLAC__METADATA_TYPE_PADDING:
2318                         return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
2319                 case FLAC__METADATA_TYPE_APPLICATION:
2320                         return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
2321                 case FLAC__METADATA_TYPE_SEEKTABLE:
2322                         return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
2323                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2324                         return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
2325                 case FLAC__METADATA_TYPE_CUESHEET:
2326                         return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
2327                 case FLAC__METADATA_TYPE_PICTURE:
2328                         return write_metadata_block_data_picture_cb_(handle, write_cb, &block->data.picture);
2329                 default:
2330                         return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
2331         }
2332 }
2333
2334 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
2335 {
2336         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
2337         const unsigned channels1 = block->channels - 1;
2338         const unsigned bps1 = block->bits_per_sample - 1;
2339
2340         /* we are using hardcoded numbers for simplicity but we should
2341          * probably eventually write a bit-level packer and use the
2342          * _STREAMINFO_ constants.
2343          */
2344         pack_uint32_(block->min_blocksize, buffer, 2);
2345         pack_uint32_(block->max_blocksize, buffer+2, 2);
2346         pack_uint32_(block->min_framesize, buffer+4, 3);
2347         pack_uint32_(block->max_framesize, buffer+7, 3);
2348         buffer[10] = (block->sample_rate >> 12) & 0xff;
2349         buffer[11] = (block->sample_rate >> 4) & 0xff;
2350         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
2351         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
2352         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
2353         memcpy(buffer+18, block->md5sum, 16);
2354
2355         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2356                 return false;
2357
2358         return true;
2359 }
2360
2361 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
2362 {
2363         unsigned i, n = block_length;
2364         FLAC__byte buffer[1024];
2365
2366         (void)block;
2367
2368         memset(buffer, 0, 1024);
2369
2370         for(i = 0; i < n/1024; i++)
2371                 if(write_cb(buffer, 1, 1024, handle) != 1024)
2372                         return false;
2373
2374         n %= 1024;
2375
2376         if(write_cb(buffer, 1, n, handle) != n)
2377                 return false;
2378
2379         return true;
2380 }
2381
2382 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
2383 {
2384         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2385
2386         if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
2387                 return false;
2388
2389         block_length -= id_bytes;
2390
2391         if(write_cb(block->data, 1, block_length, handle) != block_length)
2392                 return false;
2393
2394         return true;
2395 }
2396
2397 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
2398 {
2399         unsigned i;
2400         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2401
2402         for(i = 0; i < block->num_points; i++) {
2403                 /* some MAGIC NUMBERs here */
2404                 pack_uint64_(block->points[i].sample_number, buffer, 8);
2405                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
2406                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
2407                 if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2408                         return false;
2409         }
2410
2411         return true;
2412 }
2413
2414 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
2415 {
2416         unsigned i;
2417         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2418         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2419         FLAC__byte buffer[4]; /* magic number is asserted below */
2420
2421         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == sizeof(buffer));
2422
2423         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
2424         if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2425                 return false;
2426         if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
2427                 return false;
2428
2429         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
2430         if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2431                 return false;
2432
2433         for(i = 0; i < block->num_comments; i++) {
2434                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
2435                 if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2436                         return false;
2437                 if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
2438                         return false;
2439         }
2440
2441         return true;
2442 }
2443
2444 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
2445 {
2446         unsigned i, j, len;
2447         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
2448
2449         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2450         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
2451         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);
2452         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2453
2454         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2455         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2456         if(write_cb(block->media_catalog_number, 1, len, handle) != len)
2457                 return false;
2458
2459         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2460         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2461         pack_uint64_(block->lead_in, buffer, len);
2462         if(write_cb(buffer, 1, len, handle) != len)
2463                 return false;
2464
2465         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2466         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2467         memset(buffer, 0, len);
2468         if(block->is_cd)
2469                 buffer[0] |= 0x80;
2470         if(write_cb(buffer, 1, len, handle) != len)
2471                 return false;
2472
2473         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2474         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2475         pack_uint32_(block->num_tracks, buffer, len);
2476         if(write_cb(buffer, 1, len, handle) != len)
2477                 return false;
2478
2479         for(i = 0; i < block->num_tracks; i++) {
2480                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
2481
2482                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2483                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2484                 pack_uint64_(track->offset, buffer, len);
2485                 if(write_cb(buffer, 1, len, handle) != len)
2486                         return false;
2487
2488                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2489                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2490                 pack_uint32_(track->number, buffer, len);
2491                 if(write_cb(buffer, 1, len, handle) != len)
2492                         return false;
2493
2494                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2495                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2496                 if(write_cb(track->isrc, 1, len, handle) != len)
2497                         return false;
2498
2499                 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);
2500                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2501                 memset(buffer, 0, len);
2502                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
2503                 if(write_cb(buffer, 1, len, handle) != len)
2504                         return false;
2505
2506                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2507                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2508                 pack_uint32_(track->num_indices, buffer, len);
2509                 if(write_cb(buffer, 1, len, handle) != len)
2510                         return false;
2511
2512                 for(j = 0; j < track->num_indices; j++) {
2513                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
2514
2515                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2516                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2517                         pack_uint64_(index->offset, buffer, len);
2518                         if(write_cb(buffer, 1, len, handle) != len)
2519                                 return false;
2520
2521                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2522                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2523                         pack_uint32_(index->number, buffer, len);
2524                         if(write_cb(buffer, 1, len, handle) != len)
2525                                 return false;
2526
2527                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2528                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2529                         memset(buffer, 0, len);
2530                         if(write_cb(buffer, 1, len, handle) != len)
2531                                 return false;
2532                 }
2533         }
2534
2535         return true;
2536 }
2537
2538 FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block)
2539 {
2540         unsigned len;
2541         size_t slen;
2542         FLAC__byte buffer[4]; /* magic number is asserted below */
2543
2544         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_TYPE_LEN%8);
2545         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN%8);
2546         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN%8);
2547         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN%8);
2548         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN%8);
2549         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN%8);
2550         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN%8);
2551         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2552         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8);
2553         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8);
2554         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2555         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2556         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2557         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8);
2558
2559         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8;
2560         pack_uint32_(block->type, buffer, len);
2561         if(write_cb(buffer, 1, len, handle) != len)
2562                 return false;
2563
2564         len = FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8;
2565         slen = strlen(block->mime_type);
2566         pack_uint32_(slen, buffer, len);
2567         if(write_cb(buffer, 1, len, handle) != len)
2568                 return false;
2569         if(write_cb(block->mime_type, 1, slen, handle) != slen)
2570                 return false;
2571
2572         len = FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8;
2573         slen = strlen((const char *)block->description);
2574         pack_uint32_(slen, buffer, len);
2575         if(write_cb(buffer, 1, len, handle) != len)
2576                 return false;
2577         if(write_cb(block->description, 1, slen, handle) != slen)
2578                 return false;
2579
2580         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8;
2581         pack_uint32_(block->width, buffer, len);
2582         if(write_cb(buffer, 1, len, handle) != len)
2583                 return false;
2584
2585         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8;
2586         pack_uint32_(block->height, buffer, len);
2587         if(write_cb(buffer, 1, len, handle) != len)
2588                 return false;
2589
2590         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8;
2591         pack_uint32_(block->depth, buffer, len);
2592         if(write_cb(buffer, 1, len, handle) != len)
2593                 return false;
2594
2595         len = FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8;
2596         pack_uint32_(block->data_length, buffer, len);
2597         if(write_cb(buffer, 1, len, handle) != len)
2598                 return false;
2599         if(write_cb(block->data, 1, block->data_length, handle) != block->data_length)
2600                 return false;
2601
2602         return true;
2603 }
2604
2605 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2606 {
2607         if(write_cb(block->data, 1, block_length, handle) != block_length)
2608                 return false;
2609
2610         return true;
2611 }
2612
2613 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2614 {
2615         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2616                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2617                 return false;
2618         }
2619
2620         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2621                 return false;
2622
2623         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2624                 return false;
2625
2626         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2627                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2628                 return false;
2629         }
2630
2631         return read_metadata_block_header_(iterator);
2632 }
2633
2634 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2635 {
2636         FLAC__StreamMetadata *padding;
2637
2638         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2639                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2640                 return false;
2641         }
2642
2643         block->is_last = false;
2644
2645         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2646                 return false;
2647
2648         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2649                 return false;
2650
2651         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2652                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2653
2654         padding->is_last = padding_is_last;
2655         padding->length = padding_length;
2656
2657         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2658                 FLAC__metadata_object_delete(padding);
2659                 return false;
2660         }
2661
2662         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2663                 FLAC__metadata_object_delete(padding);
2664                 return false;
2665         }
2666
2667         FLAC__metadata_object_delete(padding);
2668
2669         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2670                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2671                 return false;
2672         }
2673
2674         return read_metadata_block_header_(iterator);
2675 }
2676
2677 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2678 {
2679         FILE *tempfile;
2680         char *tempfilename;
2681         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2682         off_t fixup_is_last_flag_offset = -1;
2683
2684         FLAC__ASSERT(0 != block || append == false);
2685
2686         if(iterator->is_last) {
2687                 if(append) {
2688                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2689                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2690                 }
2691                 else if(0 == block) {
2692                         simple_iterator_push_(iterator);
2693                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2694                                 (void)simple_iterator_pop_(iterator);
2695                                 return false;
2696                         }
2697                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2698                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2699                         if(!simple_iterator_pop_(iterator))
2700                                 return false;
2701                 }
2702         }
2703
2704         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2705                 return false;
2706
2707         if(0 != block) {
2708                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2709                         cleanup_tempfile_(&tempfile, &tempfilename);
2710                         return false;
2711                 }
2712
2713                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2714                         cleanup_tempfile_(&tempfile, &tempfilename);
2715                         return false;
2716                 }
2717         }
2718
2719         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2720                 return false;
2721
2722         if(append)
2723                 return FLAC__metadata_simple_iterator_next(iterator);
2724
2725         return true;
2726 }
2727
2728 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2729 {
2730         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2731         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2732         iterator->depth++;
2733 }
2734
2735 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2736 {
2737         FLAC__ASSERT(iterator->depth > 0);
2738         iterator->depth--;
2739         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2740                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2741                 return false;
2742         }
2743
2744         return read_metadata_block_header_(iterator);
2745 }
2746
2747 /* return meanings:
2748  * 0: ok
2749  * 1: read error
2750  * 2: seek error
2751  * 3: not a FLAC file
2752  */
2753 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2754 {
2755         FLAC__byte buffer[4];
2756         size_t n;
2757         unsigned i;
2758
2759         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == sizeof(buffer));
2760
2761         /* skip any id3v2 tag */
2762         errno = 0;
2763         n = read_cb(buffer, 1, 4, handle);
2764         if(errno)
2765                 return 1;
2766         else if(n != 4)
2767                 return 3;
2768         else if(0 == memcmp(buffer, "ID3", 3)) {
2769                 unsigned tag_length = 0;
2770
2771                 /* skip to the tag length */
2772                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2773                         return 2;
2774
2775                 /* read the length */
2776                 for(i = 0; i < 4; i++) {
2777                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2778                                 return 1;
2779                         tag_length <<= 7;
2780                         tag_length |= (buffer[0] & 0x7f);
2781                 }
2782
2783                 /* skip the rest of the tag */
2784                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2785                         return 2;
2786
2787                 /* read the stream sync code */
2788                 errno = 0;
2789                 n = read_cb(buffer, 1, 4, handle);
2790                 if(errno)
2791                         return 1;
2792                 else if(n != 4)
2793                         return 3;
2794         }
2795
2796         /* check for the fLaC signature */
2797         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2798                 return 0;
2799         else
2800                 return 3;
2801 }
2802
2803 unsigned seek_to_first_metadata_block_(FILE *f)
2804 {
2805         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2806 }
2807
2808 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2809 {
2810         const off_t offset_end = append? iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length : iterator->offset[iterator->depth];
2811
2812         if(0 != fseeko(iterator->file, 0, SEEK_SET)) {
2813                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2814                 return false;
2815         }
2816         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2817                 cleanup_tempfile_(tempfile, tempfilename);
2818                 return false;
2819         }
2820         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2821                 cleanup_tempfile_(tempfile, tempfilename);
2822                 return false;
2823         }
2824
2825         return true;
2826 }
2827
2828 FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, off_t fixup_is_last_flag_offset, FLAC__bool backup)
2829 {
2830         off_t save_offset = iterator->offset[iterator->depth];
2831         FLAC__ASSERT(0 != *tempfile);
2832
2833         if(0 != fseeko(iterator->file, save_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length, SEEK_SET)) {
2834                 cleanup_tempfile_(tempfile, tempfilename);
2835                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2836                 return false;
2837         }
2838         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2839                 cleanup_tempfile_(tempfile, tempfilename);
2840                 return false;
2841         }
2842
2843         if(fixup_is_last_code != 0) {
2844                 /*
2845                  * if code == 1, it means a block was appended to the end so
2846                  *   we have to clear the is_last flag of the previous block
2847                  * if code == -1, it means the last block was deleted so
2848                  *   we have to set the is_last flag of the previous block
2849                  */
2850                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2851                 FLAC__byte x;
2852                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2853                         cleanup_tempfile_(tempfile, tempfilename);
2854                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2855                         return false;
2856                 }
2857                 if(fread(&x, 1, 1, *tempfile) != 1) {
2858                         cleanup_tempfile_(tempfile, tempfilename);
2859                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2860                         return false;
2861                 }
2862                 if(fixup_is_last_code > 0) {
2863                         FLAC__ASSERT(x & 0x80);
2864                         x &= 0x7f;
2865                 }
2866                 else {
2867                         FLAC__ASSERT(!(x & 0x80));
2868                         x |= 0x80;
2869                 }
2870                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2871                         cleanup_tempfile_(tempfile, tempfilename);
2872                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2873                         return false;
2874                 }
2875                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
2876                         cleanup_tempfile_(tempfile, tempfilename);
2877                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2878                         return false;
2879                 }
2880         }
2881
2882         (void)fclose(iterator->file);
2883
2884         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2885                 return false;
2886
2887         if(iterator->has_stats)
2888                 set_file_stats_(iterator->filename, &iterator->stats);
2889
2890         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
2891                 return false;
2892         if(backup) {
2893                 while(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length < save_offset)
2894                         if(!FLAC__metadata_simple_iterator_next(iterator))
2895                                 return false;
2896                 return true;
2897         }
2898         else {
2899                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2900                 FLAC__ASSERT(iterator->depth == 0);
2901                 iterator->offset[0] = save_offset;
2902                 iterator->depth++;
2903                 return simple_iterator_pop_(iterator);
2904         }
2905 }
2906
2907 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
2908 {
2909         FLAC__byte buffer[8192];
2910         size_t n;
2911
2912         while(bytes > 0) {
2913                 n = min(sizeof(buffer), bytes);
2914                 if(fread(buffer, 1, n, file) != n) {
2915                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2916                         return false;
2917                 }
2918                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
2919                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2920                         return false;
2921                 }
2922                 bytes -= n;
2923         }
2924
2925         return true;
2926 }
2927
2928 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, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
2929 {
2930         FLAC__byte buffer[8192];
2931         size_t n;
2932
2933         while(bytes > 0) {
2934                 n = min(sizeof(buffer), bytes);
2935                 if(read_cb(buffer, 1, n, handle) != n) {
2936                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2937                         return false;
2938                 }
2939                 if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
2940                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2941                         return false;
2942                 }
2943                 bytes -= n;
2944         }
2945
2946         return true;
2947 }
2948
2949 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2950 {
2951         FLAC__byte buffer[8192];
2952         size_t n;
2953
2954         while(!feof(file)) {
2955                 n = fread(buffer, 1, sizeof(buffer), file);
2956                 if(n == 0 && !feof(file)) {
2957                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2958                         return false;
2959                 }
2960                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
2961                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2962                         return false;
2963                 }
2964         }
2965
2966         return true;
2967 }
2968
2969 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)
2970 {
2971         FLAC__byte buffer[8192];
2972         size_t n;
2973
2974         while(!eof_cb(handle)) {
2975                 n = read_cb(buffer, 1, sizeof(buffer), handle);
2976                 if(n == 0 && !eof_cb(handle)) {
2977                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2978                         return false;
2979                 }
2980                 if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
2981                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2982                         return false;
2983                 }
2984         }
2985
2986         return true;
2987 }
2988
2989 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
2990 {
2991         static const char *tempfile_suffix = ".metadata_edit";
2992         if(0 == tempfile_path_prefix) {
2993                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
2994                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2995                         return false;
2996                 }
2997                 strcpy(*tempfilename, filename);
2998                 strcat(*tempfilename, tempfile_suffix);
2999         }
3000         else {
3001                 const char *p = strrchr(filename, '/');
3002                 if(0 == p)
3003                         p = filename;
3004                 else
3005                         p++;
3006
3007                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
3008                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
3009                         return false;
3010                 }
3011                 strcpy(*tempfilename, tempfile_path_prefix);
3012                 strcat(*tempfilename, "/");
3013                 strcat(*tempfilename, p);
3014                 strcat(*tempfilename, tempfile_suffix);
3015         }
3016
3017         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
3018                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
3019                 return false;
3020         }
3021
3022         return true;
3023 }
3024
3025 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
3026 {
3027         FLAC__ASSERT(0 != filename);
3028         FLAC__ASSERT(0 != tempfile);
3029         FLAC__ASSERT(0 != *tempfile);
3030         FLAC__ASSERT(0 != tempfilename);
3031         FLAC__ASSERT(0 != *tempfilename);
3032         FLAC__ASSERT(0 != status);
3033
3034         (void)fclose(*tempfile);
3035         *tempfile = 0;
3036
3037 #if defined _MSC_VER || defined __MINGW32__ || defined __EMX__
3038         /* on some flavors of windows, rename() will fail if the destination already exists */
3039         if(unlink(filename) < 0) {
3040                 cleanup_tempfile_(tempfile, tempfilename);
3041                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
3042                 return false;
3043         }
3044 #endif
3045
3046         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
3047         if(0 != rename(*tempfilename, filename)) {
3048                 cleanup_tempfile_(tempfile, tempfilename);
3049                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
3050                 return false;
3051         }
3052
3053         cleanup_tempfile_(tempfile, tempfilename);
3054
3055         return true;
3056 }
3057
3058 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
3059 {
3060         if(0 != *tempfile) {
3061                 (void)fclose(*tempfile);
3062                 *tempfile = 0;
3063         }
3064
3065         if(0 != *tempfilename) {
3066                 (void)unlink(*tempfilename);
3067                 free(*tempfilename);
3068                 *tempfilename = 0;
3069         }
3070 }
3071
3072 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
3073 {
3074         FLAC__ASSERT(0 != filename);
3075         FLAC__ASSERT(0 != stats);
3076         return (0 == stat(filename, stats));
3077 }
3078
3079 void set_file_stats_(const char *filename, struct stat *stats)
3080 {
3081         struct utimbuf srctime;
3082
3083         FLAC__ASSERT(0 != filename);
3084         FLAC__ASSERT(0 != stats);
3085
3086         srctime.actime = stats->st_atime;
3087         srctime.modtime = stats->st_mtime;
3088         (void)chmod(filename, stats->st_mode);
3089         (void)utime(filename, &srctime);
3090 #if !defined _MSC_VER && !defined __MINGW32__ && !defined __EMX__
3091         (void)chown(filename, stats->st_uid, -1);
3092         (void)chown(filename, -1, stats->st_gid);
3093 #endif
3094 }
3095
3096 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
3097 {
3098         return fseeko((FILE*)handle, (off_t)offset, whence);
3099 }
3100
3101 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
3102 {
3103         return ftello((FILE*)handle);
3104 }
3105
3106 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
3107 {
3108         switch(status) {
3109                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
3110                         return FLAC__METADATA_CHAIN_STATUS_OK;
3111                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
3112                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
3113                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
3114                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
3115                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
3116                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
3117                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
3118                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
3119                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
3120                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
3121                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
3122                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
3123                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
3124                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
3125                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
3126                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
3127                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
3128                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
3129                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
3130                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
3131                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
3132                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
3133                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
3134                 default:
3135                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
3136         }
3137 }