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 #if _MSC_VER <= 1200 /* @@@ [2G limit] */
  46 #define fseeko fseek
  47 #define ftello ftell
  48 #endif
  49 #else
  50 #include <sys/types.h> /* some flavors of BSD (like OS X) require this to get time_t */
  51 #include <utime.h> /* for utime() */
  52 #include <unistd.h> /* for chown(), unlink() */
  53 #endif
  54 #include <sys/stat.h> /* for stat(), maybe chmod() */
  55
  56 #include "private/metadata.h"
  57
  58 #include "FLAC/assert.h"
  59 #include "FLAC/stream_decoder.h"
  60
  61 #ifdef max
  62 #undef max
  63 #endif
  64 #define max(a,b) ((a)>(b)?(a):(b))
  65 #ifdef min
  66 #undef min
  67 #endif
  68 #define min(a,b) ((a)<(b)?(a):(b))
  69
  70
  71 /****************************************************************************
  72  *
  73  * Local function declarations
  74  *
  75  ***************************************************************************/
  76
  77 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  78 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
  79 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
  80 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
  81 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
  82 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
  83
  84 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
  85 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
  86 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);
  87 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);
  88 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block);
  89 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);
  90 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);
  91 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);
  92 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);
  93 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block);
  94 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track);
  95 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block);
  96 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block);
  97 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);
  98
  99 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
 100 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
 101 static FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
 102 static FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
 103 static FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block);
 104 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);
 105 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);
 106 static FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block);
 107 static FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block);
 108 static FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block);
 109 static FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block);
 110 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);
 111
 112 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
 113 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
 114 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
 115
 116 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
 117 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
 118
 119 static unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb);
 120 static unsigned seek_to_first_metadata_block_(FILE *f);
 121
 122 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
 123 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);
 124
 125 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status);
 126 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);
 127 static FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status);
 128 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);
 129
 130 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 131 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
 132 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
 133
 134 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats);
 135 static void set_file_stats_(const char *filename, struct stat *stats);
 136
 137 static int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence);
 138 static FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle);
 139
 140 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
 141
 142
 143 #ifdef FLAC__VALGRIND_TESTING
 144 static size_t local__fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
 145 {
 146         size_t ret = fwrite(ptr, size, nmemb, stream);
 147         if(!ferror(stream))
 148                 fflush(stream);
 149         return ret;
 150 }
 151 #else
 152 #define local__fwrite fwrite
 153 #endif
 154
 155 /****************************************************************************
 156  *
 157  * Level 0 implementation
 158  *
 159  ***************************************************************************/
 160
 161 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
 162 static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
 163 static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
 164
 165 typedef struct {
 166         FLAC__bool got_error;
 167         FLAC__StreamMetadata *object;
 168 } level0_client_data;
 169
 170 static FLAC__StreamMetadata *get_one_metadata_block_(const char *filename, FLAC__MetadataType type)
 171 {
 172         level0_client_data cd;
 173         FLAC__StreamDecoder *decoder;
 174
 175         FLAC__ASSERT(0 != filename);
 176
 177         cd.got_error = false;
 178         cd.object = 0;
 179
 180         decoder = FLAC__stream_decoder_new();
 181
 182         if(0 == decoder)
 183                 return 0;
 184
 185         FLAC__stream_decoder_set_md5_checking(decoder, false);
 186         FLAC__stream_decoder_set_metadata_ignore_all(decoder);
 187         FLAC__stream_decoder_set_metadata_respond(decoder, type);
 188
 189         if(FLAC__stream_decoder_init_file(decoder, filename, write_callback_, metadata_callback_, error_callback_, &cd) != FLAC__STREAM_DECODER_INIT_STATUS_OK || cd.got_error) {
 190                 (void)FLAC__stream_decoder_finish(decoder);
 191                 FLAC__stream_decoder_delete(decoder);
 192                 return 0;
 193         }
 194
 195         if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
 196                 (void)FLAC__stream_decoder_finish(decoder);
 197                 FLAC__stream_decoder_delete(decoder);
 198                 if(0 != cd.object)
 199                         FLAC__metadata_object_delete(cd.object);
 200                 return 0;
 201         }
 202
 203         (void)FLAC__stream_decoder_finish(decoder);
 204         FLAC__stream_decoder_delete(decoder);
 205
 206         return cd.object;
 207 }
 208
 209 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 210 {
 211         FLAC__StreamMetadata *object;
 212
 213         FLAC__ASSERT(0 != filename);
 214         FLAC__ASSERT(0 != streaminfo);
 215
 216         object = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_STREAMINFO);
 217
 218         if (object) {
 219                 /* can just copy the contents since STREAMINFO has no internal structure */
 220                 *streaminfo = *object;
 221                 FLAC__metadata_object_delete(object);
 222                 return true;
 223         }
 224         else {
 225                 return false;
 226         }
 227 }
 228
 229 FLAC_API FLAC__bool FLAC__metadata_get_tags(const char *filename, FLAC__StreamMetadata **tags)
 230 {
 231         FLAC__ASSERT(0 != filename);
 232         FLAC__ASSERT(0 != tags);
 233
 234         *tags = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_VORBIS_COMMENT);
 235
 236         return 0 != *tags;
 237 }
 238
 239 FLAC_API FLAC__bool FLAC__metadata_get_cuesheet(const char *filename, FLAC__StreamMetadata **cuesheet)
 240 {
 241         FLAC__ASSERT(0 != filename);
 242         FLAC__ASSERT(0 != cuesheet);
 243
 244         *cuesheet = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_CUESHEET);
 245
 246         return 0 != *cuesheet;
 247 }
 248
 249 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
 250 {
 251         (void)decoder, (void)frame, (void)buffer, (void)client_data;
 252
 253         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 254 }
 255
 256 void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
 257 {
 258         level0_client_data *cd = (level0_client_data *)client_data;
 259         (void)decoder;
 260
 261         /*
 262          * we assume we only get here when the one metadata block we were
 263          * looking for was passed to us
 264          */
 265         if(!cd->got_error && 0 == cd->object) {
 266                 if(0 == (cd->object = FLAC__metadata_object_clone(metadata)))
 267                         cd->got_error = true;
 268         }
 269 }
 270
 271 void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
 272 {
 273         level0_client_data *cd = (level0_client_data *)client_data;
 274         (void)decoder;
 275
 276         if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
 277                 cd->got_error = true;
 278 }
 279
 280 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, unsigned max_colors)
 281 {
 282         FLAC__Metadata_SimpleIterator *it;
 283         FLAC__uint64 max_area_seen = 0;
 284         FLAC__uint64 max_depth_seen = 0;
 285
 286         FLAC__ASSERT(0 != filename);
 287         FLAC__ASSERT(0 != picture);
 288
 289         *picture = 0;
 290
 291         it = FLAC__metadata_simple_iterator_new();
 292         if(0 == it)
 293                 return false;
 294         if(!FLAC__metadata_simple_iterator_init(it, filename, /*read_only=*/true, /*preserve_file_stats=*/true)) {
 295                 FLAC__metadata_simple_iterator_delete(it);
 296                 return false;
 297         }
 298         do {
 299                 if(FLAC__metadata_simple_iterator_get_block_type(it) == FLAC__METADATA_TYPE_PICTURE) {
 300                         FLAC__StreamMetadata *obj = FLAC__metadata_simple_iterator_get_block(it);
 301                         FLAC__uint64 area = (FLAC__uint64)obj->data.picture.width * (FLAC__uint64)obj->data.picture.height;
 302                         /* check constraints */
 303                         if(
 304                                 (type == (FLAC__StreamMetadata_Picture_Type)(-1) || type == obj->data.picture.type) &&
 305                                 (mime_type == 0 || !strcmp(mime_type, obj->data.picture.mime_type)) &&
 306                                 (description == 0 || !strcmp((const char *)description, (const char *)obj->data.picture.description)) &&
 307                                 obj->data.picture.width <= max_width &&
 308                                 obj->data.picture.height <= max_height &&
 309                                 obj->data.picture.depth <= max_depth &&
 310                                 obj->data.picture.colors <= max_colors &&
 311                                 (area > max_area_seen || (area == max_area_seen && obj->data.picture.depth > max_depth_seen))
 312                         ) {
 313                                 if(*picture)
 314                                         FLAC__metadata_object_delete(*picture);
 315                                 *picture = obj;
 316                                 max_area_seen = area;
 317                                 max_depth_seen = obj->data.picture.depth;
 318                         }
 319                         else {
 320                                 FLAC__metadata_object_delete(obj);
 321                         }
 322                 }
 323         } while(FLAC__metadata_simple_iterator_next(it));
 324
 325         FLAC__metadata_simple_iterator_delete(it);
 326
 327         return (0 != *picture);
 328 }
 329
 330
 331 /****************************************************************************
 332  *
 333  * Level 1 implementation
 334  *
 335  ***************************************************************************/
 336
 337 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
 338 /* 1 for initial offset, +4 for our own personal use */
 339
 340 struct FLAC__Metadata_SimpleIterator {
 341         FILE *file;
 342         char *filename, *tempfile_path_prefix;
 343         struct stat stats;
 344         FLAC__bool has_stats;
 345         FLAC__bool is_writable;
 346         FLAC__Metadata_SimpleIteratorStatus status;
 347         off_t offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
 348         off_t first_offset; /* this is the offset to the STREAMINFO block */
 349         unsigned depth;
 350         /* this is the metadata block header of the current block we are pointing to: */
 351         FLAC__bool is_last;
 352         FLAC__MetadataType type;
 353         unsigned length;
 354 };
 355
 356 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 357         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
 358         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
 359         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
 360         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
 361         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
 362         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
 363         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
 364         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
 365         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
 366         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
 367         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
 368         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
 369         "FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
 370 };
 371
 372
 373 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
 374 {
 375         FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 376
 377         if(0 != iterator) {
 378                 iterator->file = 0;
 379                 iterator->filename = 0;
 380                 iterator->tempfile_path_prefix = 0;
 381                 iterator->has_stats = false;
 382                 iterator->is_writable = false;
 383                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 384                 iterator->first_offset = iterator->offset[0] = -1;
 385                 iterator->depth = 0;
 386         }
 387
 388         return iterator;
 389 }
 390
 391 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
 392 {
 393         FLAC__ASSERT(0 != iterator);
 394
 395         if(0 != iterator->file) {
 396                 fclose(iterator->file);
 397                 iterator->file = 0;
 398                 if(iterator->has_stats)
 399                         set_file_stats_(iterator->filename, &iterator->stats);
 400         }
 401         if(0 != iterator->filename) {
 402                 free(iterator->filename);
 403                 iterator->filename = 0;
 404         }
 405         if(0 != iterator->tempfile_path_prefix) {
 406                 free(iterator->tempfile_path_prefix);
 407                 iterator->tempfile_path_prefix = 0;
 408         }
 409 }
 410
 411 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
 412 {
 413         FLAC__ASSERT(0 != iterator);
 414
 415         simple_iterator_free_guts_(iterator);
 416         free(iterator);
 417 }
 418
 419 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
 420 {
 421         FLAC__Metadata_SimpleIteratorStatus status;
 422
 423         FLAC__ASSERT(0 != iterator);
 424
 425         status = iterator->status;
 426         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
 427         return status;
 428 }
 429
 430 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
 431 {
 432         unsigned ret;
 433
 434         FLAC__ASSERT(0 != iterator);
 435
 436         if(read_only || 0 == (iterator->file = fopen(iterator->filename, "r+b"))) {
 437                 iterator->is_writable = false;
 438                 if(read_only || errno == EACCES) {
 439                         if(0 == (iterator->file = fopen(iterator->filename, "rb"))) {
 440                                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 441                                 return false;
 442                         }
 443                 }
 444                 else {
 445                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
 446                         return false;
 447                 }
 448         }
 449         else {
 450                 iterator->is_writable = true;
 451         }
 452
 453         ret = seek_to_first_metadata_block_(iterator->file);
 454         switch(ret) {
 455                 case 0:
 456                         iterator->depth = 0;
 457                         iterator->first_offset = iterator->offset[iterator->depth] = ftello(iterator->file);
 458                         return read_metadata_block_header_(iterator);
 459                 case 1:
 460                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
 461                         return false;
 462                 case 2:
 463                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 464                         return false;
 465                 case 3:
 466                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
 467                         return false;
 468                 default:
 469                         FLAC__ASSERT(0);
 470                         return false;
 471         }
 472 }
 473
 474 #if 0
 475 @@@ If we decide to finish implementing this, put this comment back in metadata.h
 476 /*
 477  * The 'tempfile_path_prefix' allows you to specify a directory where
 478  * tempfiles should go.  Remember that if your metadata edits cause the
 479  * FLAC file to grow, the entire file will have to be rewritten.  If
 480  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
 481  * same directory as the original FLAC file.  This makes replacing the
 482  * original with the tempfile fast but requires extra space in the same
 483  * partition for the tempfile.  If space is a problem, you can pass a
 484  * directory name belonging to a different partition in
 485  * 'tempfile_path_prefix'.  Note that you should use the forward slash
 486  * '/' as the directory separator.  A trailing slash is not needed; it
 487  * will be added automatically.
 488  */
 489 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
 490 #endif
 491
 492 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)
 493 {
 494         const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'rename(...)' for what it will take to finish implementing this */
 495
 496         FLAC__ASSERT(0 != iterator);
 497         FLAC__ASSERT(0 != filename);
 498
 499         simple_iterator_free_guts_(iterator);
 500
 501         if(!read_only && preserve_file_stats)
 502                 iterator->has_stats = get_file_stats_(filename, &iterator->stats);
 503
 504         if(0 == (iterator->filename = strdup(filename))) {
 505                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 506                 return false;
 507         }
 508         if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
 509                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 510                 return false;
 511         }
 512
 513         return simple_iterator_prime_input_(iterator, read_only);
 514 }
 515
 516 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
 517 {
 518         FLAC__ASSERT(0 != iterator);
 519         FLAC__ASSERT(0 != iterator->file);
 520
 521         return iterator->is_writable;
 522 }
 523
 524 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
 525 {
 526         FLAC__ASSERT(0 != iterator);
 527         FLAC__ASSERT(0 != iterator->file);
 528
 529         if(iterator->is_last)
 530                 return false;
 531
 532         if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
 533                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 534                 return false;
 535         }
 536
 537         iterator->offset[iterator->depth] = ftello(iterator->file);
 538
 539         return read_metadata_block_header_(iterator);
 540 }
 541
 542 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
 543 {
 544         off_t this_offset;
 545
 546         FLAC__ASSERT(0 != iterator);
 547         FLAC__ASSERT(0 != iterator->file);
 548
 549         if(iterator->offset[iterator->depth] == iterator->first_offset)
 550                 return false;
 551
 552         if(0 != fseeko(iterator->file, iterator->first_offset, SEEK_SET)) {
 553                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 554                 return false;
 555         }
 556         this_offset = iterator->first_offset;
 557         if(!read_metadata_block_header_(iterator))
 558                 return false;
 559
 560         /* we ignore any error from ftello() and catch it in fseeko() */
 561         while(ftello(iterator->file) + (off_t)iterator->length < iterator->offset[iterator->depth]) {
 562                 if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
 563                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 564                         return false;
 565                 }
 566                 this_offset = ftello(iterator->file);
 567                 if(!read_metadata_block_header_(iterator))
 568                         return false;
 569         }
 570
 571         iterator->offset[iterator->depth] = this_offset;
 572
 573         return true;
 574 }
 575
 576 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
 577 {
 578         FLAC__ASSERT(0 != iterator);
 579         FLAC__ASSERT(0 != iterator->file);
 580
 581         return iterator->type;
 582 }
 583
 584 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
 585 {
 586         FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
 587
 588         FLAC__ASSERT(0 != iterator);
 589         FLAC__ASSERT(0 != iterator->file);
 590
 591         if(0 != block) {
 592                 block->is_last = iterator->is_last;
 593                 block->length = iterator->length;
 594
 595                 if(!read_metadata_block_data_(iterator, block)) {
 596                         FLAC__metadata_object_delete(block);
 597                         return 0;
 598                 }
 599
 600                 /* back up to the beginning of the block data to stay consistent */
 601                 if(0 != fseeko(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
 602                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
 603                         FLAC__metadata_object_delete(block);
 604                         return 0;
 605                 }
 606         }
 607         else
 608                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 609
 610         return block;
 611 }
 612
 613 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 614 {
 615         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth];)
 616         FLAC__bool ret;
 617
 618         FLAC__ASSERT(0 != iterator);
 619         FLAC__ASSERT(0 != iterator->file);
 620         FLAC__ASSERT(0 != block);
 621
 622         if(!iterator->is_writable) {
 623                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
 624                 return false;
 625         }
 626
 627         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 628                 if(iterator->type != block->type) {
 629                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 630                         return false;
 631                 }
 632         }
 633
 634         block->is_last = iterator->is_last;
 635
 636         if(iterator->length == block->length)
 637                 return write_metadata_block_stationary_(iterator, block);
 638         else if(iterator->length > block->length) {
 639                 if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
 640                         ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
 641                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 642                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 643                         return ret;
 644                 }
 645                 else {
 646                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 647                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 648                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 649                         return ret;
 650                 }
 651         }
 652         else /* iterator->length < block->length */ {
 653                 unsigned padding_leftover = 0;
 654                 FLAC__bool padding_is_last = false;
 655                 if(use_padding) {
 656                         /* first see if we can even use padding */
 657                         if(iterator->is_last) {
 658                                 use_padding = false;
 659                         }
 660                         else {
 661                                 const unsigned extra_padding_bytes_required = block->length - iterator->length;
 662                                 simple_iterator_push_(iterator);
 663                                 if(!FLAC__metadata_simple_iterator_next(iterator)) {
 664                                         (void)simple_iterator_pop_(iterator);
 665                                         return false;
 666                                 }
 667                                 if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 668                                         use_padding = false;
 669                                 }
 670                                 else {
 671                                         if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
 672                                                 padding_leftover = 0;
 673                                                 block->is_last = iterator->is_last;
 674                                         }
 675                                         else if(iterator->length < extra_padding_bytes_required)
 676                                                 use_padding = false;
 677                                         else {
 678                                                 padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
 679                                                 padding_is_last = iterator->is_last;
 680                                                 block->is_last = false;
 681                                         }
 682                                 }
 683                                 if(!simple_iterator_pop_(iterator))
 684                                         return false;
 685                         }
 686                 }
 687                 if(use_padding) {
 688                         if(padding_leftover == 0) {
 689                                 ret = write_metadata_block_stationary_(iterator, block);
 690                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 691                                 FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 692                                 return ret;
 693                         }
 694                         else {
 695                                 FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 696                                 ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 697                                 FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 698                                 FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 699                                 return ret;
 700                         }
 701                 }
 702                 else {
 703                         ret = rewrite_whole_file_(iterator, block, /*append=*/false);
 704                         FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
 705                         FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 706                         return ret;
 707                 }
 708         }
 709 }
 710
 711 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
 712 {
 713         unsigned padding_leftover = 0;
 714         FLAC__bool padding_is_last = false;
 715
 716         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
 717         FLAC__bool ret;
 718
 719         FLAC__ASSERT(0 != iterator);
 720         FLAC__ASSERT(0 != iterator->file);
 721         FLAC__ASSERT(0 != block);
 722
 723         if(!iterator->is_writable)
 724                 return false;
 725
 726         if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
 727                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 728                 return false;
 729         }
 730
 731         block->is_last = iterator->is_last;
 732
 733         if(use_padding) {
 734                 /* first see if we can even use padding */
 735                 if(iterator->is_last) {
 736                         use_padding = false;
 737                 }
 738                 else {
 739                         simple_iterator_push_(iterator);
 740                         if(!FLAC__metadata_simple_iterator_next(iterator)) {
 741                                 (void)simple_iterator_pop_(iterator);
 742                                 return false;
 743                         }
 744                         if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
 745                                 use_padding = false;
 746                         }
 747                         else {
 748                                 if(iterator->length == block->length) {
 749                                         padding_leftover = 0;
 750                                         block->is_last = iterator->is_last;
 751                                 }
 752                                 else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
 753                                         use_padding = false;
 754                                 else {
 755                                         padding_leftover = iterator->length - block->length;
 756                                         padding_is_last = iterator->is_last;
 757                                         block->is_last = false;
 758                                 }
 759                         }
 760                         if(!simple_iterator_pop_(iterator))
 761                                 return false;
 762                 }
 763         }
 764         if(use_padding) {
 765                 /* move to the next block, which is suitable padding */
 766                 if(!FLAC__metadata_simple_iterator_next(iterator))
 767                         return false;
 768                 if(padding_leftover == 0) {
 769                         ret = write_metadata_block_stationary_(iterator, block);
 770                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 771                         FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 772                         return ret;
 773                 }
 774                 else {
 775                         FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
 776                         ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
 777                         FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 778                         FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 779                         return ret;
 780                 }
 781         }
 782         else {
 783                 ret = rewrite_whole_file_(iterator, block, /*append=*/true);
 784                 FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
 785                 FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
 786                 return ret;
 787         }
 788 }
 789
 790 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
 791 {
 792         FLAC__ASSERT_DECLARATION(off_t debug_target_offset = iterator->offset[iterator->depth];)
 793         FLAC__bool ret;
 794
 795         if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
 796                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
 797                 return false;
 798         }
 799
 800         if(use_padding) {
 801                 FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
 802                 if(0 == padding) {
 803                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
 804                         return false;
 805                 }
 806                 padding->length = iterator->length;
 807                 if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
 808                         FLAC__metadata_object_delete(padding);
 809                         return false;
 810                 }
 811                 FLAC__metadata_object_delete(padding);
 812                 if(!FLAC__metadata_simple_iterator_prev(iterator))
 813                         return false;
 814                 FLAC__ASSERT(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length == debug_target_offset);
 815                 FLAC__ASSERT(ftello(iterator->file) + (off_t)iterator->length == debug_target_offset);
 816                 return true;
 817         }
 818         else {
 819                 ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
 820                 FLAC__ASSERT(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length == debug_target_offset);
 821                 FLAC__ASSERT(ftello(iterator->file) + (off_t)iterator->length == debug_target_offset);
 822                 return ret;
 823         }
 824 }
 825
 826
 827
 828 /****************************************************************************
 829  *
 830  * Level 2 implementation
 831  *
 832  ***************************************************************************/
 833
 834
 835 typedef struct FLAC__Metadata_Node {
 836         FLAC__StreamMetadata *data;
 837         struct FLAC__Metadata_Node *prev, *next;
 838 } FLAC__Metadata_Node;
 839
 840 struct FLAC__Metadata_Chain {
 841         char *filename; /* will be NULL if using callbacks */
 842         FLAC__Metadata_Node *head;
 843         FLAC__Metadata_Node *tail;
 844         unsigned nodes;
 845         FLAC__Metadata_ChainStatus status;
 846         off_t first_offset, last_offset;
 847         /*
 848          * This is the length of the chain initially read from the FLAC file.
 849          * it is used to compare against the current length to decide whether
 850          * or not the whole file has to be rewritten.
 851          */
 852         off_t initial_length;
 853 };
 854
 855 struct FLAC__Metadata_Iterator {
 856         FLAC__Metadata_Chain *chain;
 857         FLAC__Metadata_Node *current;
 858 };
 859
 860 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 861         "FLAC__METADATA_CHAIN_STATUS_OK",
 862         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 863         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 864         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 865         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 866         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 867         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 868         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 869         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 870         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 871         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 872         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 873         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
 874         "FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
 875         "FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
 876         "FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
 877 };
 878
 879
 880 static FLAC__Metadata_Node *node_new_()
 881 {
 882         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 883 }
 884
 885 static void node_delete_(FLAC__Metadata_Node *node)
 886 {
 887         FLAC__ASSERT(0 != node);
 888         if(0 != node->data)
 889                 FLAC__metadata_object_delete(node->data);
 890         free(node);
 891 }
 892
 893 static void chain_init_(FLAC__Metadata_Chain *chain)
 894 {
 895         FLAC__ASSERT(0 != chain);
 896
 897         chain->filename = 0;
 898         chain->head = chain->tail = 0;
 899         chain->nodes = 0;
 900         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 901         chain->initial_length = 0;
 902 }
 903
 904 static void chain_clear_(FLAC__Metadata_Chain *chain)
 905 {
 906         FLAC__Metadata_Node *node, *next;
 907
 908         FLAC__ASSERT(0 != chain);
 909
 910         for(node = chain->head; node; ) {
 911                 next = node->next;
 912                 node_delete_(node);
 913                 node = next;
 914         }
 915
 916         if(0 != chain->filename)
 917                 free(chain->filename);
 918
 919         chain_init_(chain);
 920 }
 921
 922 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 923 {
 924         FLAC__ASSERT(0 != chain);
 925         FLAC__ASSERT(0 != node);
 926         FLAC__ASSERT(0 != node->data);
 927
 928         node->next = node->prev = 0;
 929         node->data->is_last = true;
 930         if(0 != chain->tail)
 931                 chain->tail->data->is_last = false;
 932
 933         if(0 == chain->head)
 934                 chain->head = node;
 935         else {
 936                 FLAC__ASSERT(0 != chain->tail);
 937                 chain->tail->next = node;
 938                 node->prev = chain->tail;
 939         }
 940         chain->tail = node;
 941         chain->nodes++;
 942 }
 943
 944 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 945 {
 946         FLAC__ASSERT(0 != chain);
 947         FLAC__ASSERT(0 != node);
 948
 949         if(node == chain->head)
 950                 chain->head = node->next;
 951         else
 952                 node->prev->next = node->next;
 953
 954         if(node == chain->tail)
 955                 chain->tail = node->prev;
 956         else
 957                 node->next->prev = node->prev;
 958
 959         if(0 != chain->tail)
 960                 chain->tail->data->is_last = true;
 961
 962         chain->nodes--;
 963 }
 964
 965 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 966 {
 967         chain_remove_node_(chain, node);
 968         node_delete_(node);
 969 }
 970
 971 static off_t chain_calculate_length_(FLAC__Metadata_Chain *chain)
 972 {
 973         const FLAC__Metadata_Node *node;
 974         off_t length = 0;
 975         for(node = chain->head; node; node = node->next)
 976                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 977         return length;
 978 }
 979
 980 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 981 {
 982         FLAC__ASSERT(0 != node);
 983         FLAC__ASSERT(0 != node->data);
 984         FLAC__ASSERT(0 != iterator);
 985         FLAC__ASSERT(0 != iterator->current);
 986         FLAC__ASSERT(0 != iterator->chain);
 987         FLAC__ASSERT(0 != iterator->chain->head);
 988         FLAC__ASSERT(0 != iterator->chain->tail);
 989
 990         node->data->is_last = false;
 991
 992         node->prev = iterator->current->prev;
 993         node->next = iterator->current;
 994
 995         if(0 == node->prev)
 996                 iterator->chain->head = node;
 997         else
 998                 node->prev->next = node;
 999
1000         iterator->current->prev = node;
1001
1002         iterator->chain->nodes++;
1003 }
1004
1005 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
1006 {
1007         FLAC__ASSERT(0 != node);
1008         FLAC__ASSERT(0 != node->data);
1009         FLAC__ASSERT(0 != iterator);
1010         FLAC__ASSERT(0 != iterator->current);
1011         FLAC__ASSERT(0 != iterator->chain);
1012         FLAC__ASSERT(0 != iterator->chain->head);
1013         FLAC__ASSERT(0 != iterator->chain->tail);
1014
1015         iterator->current->data->is_last = false;
1016
1017         node->prev = iterator->current;
1018         node->next = iterator->current->next;
1019
1020         if(0 == node->next)
1021                 iterator->chain->tail = node;
1022         else
1023                 node->next->prev = node;
1024
1025         node->prev->next = node;
1026
1027         iterator->chain->tail->data->is_last = true;
1028
1029         iterator->chain->nodes++;
1030 }
1031
1032 /* return true iff node and node->next are both padding */
1033 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
1034 {
1035         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
1036                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
1037                 node->data->length += growth;
1038
1039                 chain_delete_node_(chain, node->next);
1040                 return true;
1041         }
1042         else
1043                 return false;
1044 }
1045
1046 /* Returns the new length of the chain, or 0 if there was an error. */
1047 /* WATCHOUT: This can get called multiple times before a write, so
1048  * it should still work when this happens.
1049  */
1050 /* WATCHOUT: Make sure to also update the logic in
1051  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
1052  */
1053 static off_t chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1054 {
1055         off_t current_length = chain_calculate_length_(chain);
1056
1057         if(use_padding) {
1058                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1059                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1060                         const off_t delta = chain->initial_length - current_length;
1061                         chain->tail->data->length += delta;
1062                         current_length += delta;
1063                         FLAC__ASSERT(current_length == chain->initial_length);
1064                 }
1065                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1066                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1067                         FLAC__StreamMetadata *padding;
1068                         FLAC__Metadata_Node *node;
1069                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1070                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1071                                 return 0;
1072                         }
1073                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1074                         if(0 == (node = node_new_())) {
1075                                 FLAC__metadata_object_delete(padding);
1076                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1077                                 return 0;
1078                         }
1079                         node->data = padding;
1080                         chain_append_node_(chain, node);
1081                         current_length = chain_calculate_length_(chain);
1082                         FLAC__ASSERT(current_length == chain->initial_length);
1083                 }
1084                 /* 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 */
1085                 else if(current_length > chain->initial_length) {
1086                         const off_t delta = current_length - chain->initial_length;
1087                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1088                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1089                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1090                                         chain_delete_node_(chain, chain->tail);
1091                                         current_length = chain_calculate_length_(chain);
1092                                         FLAC__ASSERT(current_length == chain->initial_length);
1093                                 }
1094                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1095                                 else if((off_t)chain->tail->data->length >= delta) {
1096                                         chain->tail->data->length -= delta;
1097                                         current_length -= delta;
1098                                         FLAC__ASSERT(current_length == chain->initial_length);
1099                                 }
1100                         }
1101                 }
1102         }
1103
1104         return current_length;
1105 }
1106
1107 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)
1108 {
1109         FLAC__Metadata_Node *node;
1110
1111         FLAC__ASSERT(0 != chain);
1112
1113         /* we assume we're already at the beginning of the file */
1114
1115         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
1116                 case 0:
1117                         break;
1118                 case 1:
1119                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1120                         return false;
1121                 case 2:
1122                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1123                         return false;
1124                 case 3:
1125                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
1126                         return false;
1127                 default:
1128                         FLAC__ASSERT(0);
1129                         return false;
1130         }
1131
1132         {
1133                 FLAC__int64 pos = tell_cb(handle);
1134                 if(pos < 0) {
1135                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1136                         return false;
1137                 }
1138                 chain->first_offset = (off_t)pos;
1139         }
1140
1141         {
1142                 FLAC__bool is_last;
1143                 FLAC__MetadataType type;
1144                 unsigned length;
1145
1146                 do {
1147                         node = node_new_();
1148                         if(0 == node) {
1149                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1150                                 return false;
1151                         }
1152
1153                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
1154                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1155                                 return false;
1156                         }
1157
1158                         node->data = FLAC__metadata_object_new(type);
1159                         if(0 == node->data) {
1160                                 node_delete_(node);
1161                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1162                                 return false;
1163                         }
1164
1165                         node->data->is_last = is_last;
1166                         node->data->length = length;
1167
1168                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
1169                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1170                                 node_delete_(node);
1171                                 return false;
1172                         }
1173                         chain_append_node_(chain, node);
1174                 } while(!is_last);
1175         }
1176
1177         {
1178                 FLAC__int64 pos = tell_cb(handle);
1179                 if(pos < 0) {
1180                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1181                         return false;
1182                 }
1183                 chain->last_offset = (off_t)pos;
1184         }
1185
1186         chain->initial_length = chain_calculate_length_(chain);
1187
1188         return true;
1189 }
1190
1191 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)
1192 {
1193         FLAC__Metadata_Node *node;
1194
1195         FLAC__ASSERT(0 != chain);
1196         FLAC__ASSERT(0 != chain->head);
1197
1198         if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
1199                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1200                 return false;
1201         }
1202
1203         for(node = chain->head; node; node = node->next) {
1204                 if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
1205                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1206                         return false;
1207                 }
1208                 if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
1209                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1210                         return false;
1211                 }
1212         }
1213
1214         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1215
1216         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1217         return true;
1218 }
1219
1220 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
1221 {
1222         FILE *file;
1223         FLAC__bool ret;
1224
1225         FLAC__ASSERT(0 != chain->filename);
1226
1227         if(0 == (file = fopen(chain->filename, "r+b"))) {
1228                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1229                 return false;
1230         }
1231
1232         /* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
1233         ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
1234
1235         fclose(file);
1236
1237         return ret;
1238 }
1239
1240 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1241 {
1242         FILE *f, *tempfile;
1243         char *tempfilename;
1244         FLAC__Metadata_SimpleIteratorStatus status;
1245         const FLAC__Metadata_Node *node;
1246
1247         FLAC__ASSERT(0 != chain);
1248         FLAC__ASSERT(0 != chain->filename);
1249         FLAC__ASSERT(0 != chain->head);
1250
1251         /* copy the file prefix (data up to first metadata block */
1252         if(0 == (f = fopen(chain->filename, "rb"))) {
1253                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1254                 return false;
1255         }
1256         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1257                 chain->status = get_equivalent_status_(status);
1258                 cleanup_tempfile_(&tempfile, &tempfilename);
1259                 return false;
1260         }
1261         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1262                 chain->status = get_equivalent_status_(status);
1263                 cleanup_tempfile_(&tempfile, &tempfilename);
1264                 return false;
1265         }
1266
1267         /* write the metadata */
1268         for(node = chain->head; node; node = node->next) {
1269                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1270                         chain->status = get_equivalent_status_(status);
1271                         return false;
1272                 }
1273                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1274                         chain->status = get_equivalent_status_(status);
1275                         return false;
1276                 }
1277         }
1278         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1279
1280         /* copy the file postfix (everything after the metadata) */
1281         if(0 != fseeko(f, chain->last_offset, SEEK_SET)) {
1282                 cleanup_tempfile_(&tempfile, &tempfilename);
1283                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1284                 return false;
1285         }
1286         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1287                 cleanup_tempfile_(&tempfile, &tempfilename);
1288                 chain->status = get_equivalent_status_(status);
1289                 return false;
1290         }
1291
1292         /* move the tempfile on top of the original */
1293         (void)fclose(f);
1294         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1295                 return false;
1296
1297         return true;
1298 }
1299
1300 /* assumes 'handle' is already at beginning of file */
1301 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)
1302 {
1303         FLAC__Metadata_SimpleIteratorStatus status;
1304         const FLAC__Metadata_Node *node;
1305
1306         FLAC__ASSERT(0 != chain);
1307         FLAC__ASSERT(0 == chain->filename);
1308         FLAC__ASSERT(0 != chain->head);
1309
1310         /* copy the file prefix (data up to first metadata block */
1311         if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
1312                 chain->status = get_equivalent_status_(status);
1313                 return false;
1314         }
1315
1316         /* write the metadata */
1317         for(node = chain->head; node; node = node->next) {
1318                 if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
1319                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1320                         return false;
1321                 }
1322                 if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
1323                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1324                         return false;
1325                 }
1326         }
1327         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1328
1329         /* copy the file postfix (everything after the metadata) */
1330         if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
1331                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1332                 return false;
1333         }
1334         if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
1335                 chain->status = get_equivalent_status_(status);
1336                 return false;
1337         }
1338
1339         return true;
1340 }
1341
1342 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1343 {
1344         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1345
1346         if(0 != chain)
1347                 chain_init_(chain);
1348
1349         return chain;
1350 }
1351
1352 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1353 {
1354         FLAC__ASSERT(0 != chain);
1355
1356         chain_clear_(chain);
1357
1358         free(chain);
1359 }
1360
1361 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1362 {
1363         FLAC__Metadata_ChainStatus status;
1364
1365         FLAC__ASSERT(0 != chain);
1366
1367         status = chain->status;
1368         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1369         return status;
1370 }
1371
1372 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1373 {
1374         FILE *file;
1375         FLAC__bool ret;
1376
1377         FLAC__ASSERT(0 != chain);
1378         FLAC__ASSERT(0 != filename);
1379
1380         chain_clear_(chain);
1381
1382         if(0 == (chain->filename = strdup(filename))) {
1383                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1384                 return false;
1385         }
1386
1387         if(0 == (file = fopen(filename, "rb"))) {
1388                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1389                 return false;
1390         }
1391
1392         /* chain_read_cb_() sets chain->status for us */
1393         ret = chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_);
1394
1395         fclose(file);
1396
1397         return ret;
1398 }
1399
1400 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1401 {
1402         FLAC__ASSERT(0 != chain);
1403
1404         chain_clear_(chain);
1405
1406         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
1407                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1408                 return false;
1409         }
1410
1411         /* rewind */
1412         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1413                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1414                 return false;
1415         }
1416
1417         if(!chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell))
1418                 return false; /* chain->status is already set by chain_read_cb_ */
1419
1420         return true;
1421 }
1422
1423 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1424 {
1425         /* This does all the same checks that are in chain_prepare_for_write_()
1426          * but doesn't actually alter the chain.  Make sure to update the logic
1427          * here if chain_prepare_for_write_() changes.
1428          */
1429         const off_t current_length = chain_calculate_length_(chain);
1430
1431         FLAC__ASSERT(0 != chain);
1432
1433         if(use_padding) {
1434                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1435                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING)
1436                         return false;
1437                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1438                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length)
1439                         return false;
1440                 /* 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 */
1441                 else if(current_length > chain->initial_length) {
1442                         const off_t delta = current_length - chain->initial_length;
1443                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1444                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1445                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta)
1446                                         return false;
1447                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1448                                 else if((off_t)chain->tail->data->length >= delta)
1449                                         return false;
1450                         }
1451                 }
1452         }
1453
1454         return (current_length != chain->initial_length);
1455 }
1456
1457 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1458 {
1459         struct stat stats;
1460         const char *tempfile_path_prefix = 0;
1461         off_t current_length;
1462
1463         FLAC__ASSERT(0 != chain);
1464
1465         if (0 == chain->filename) {
1466                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1467                 return false;
1468         }
1469
1470         current_length = chain_prepare_for_write_(chain, use_padding);
1471
1472         /* a return value of 0 means there was an error; chain->status is already set */
1473         if (0 == current_length)
1474                 return false;
1475
1476         if(preserve_file_stats)
1477                 get_file_stats_(chain->filename, &stats);
1478
1479         if(current_length == chain->initial_length) {
1480                 if(!chain_rewrite_metadata_in_place_(chain))
1481                         return false;
1482         }
1483         else {
1484                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1485                         return false;
1486
1487                 /* recompute lengths and offsets */
1488                 {
1489                         const FLAC__Metadata_Node *node;
1490                         chain->initial_length = current_length;
1491                         chain->last_offset = chain->first_offset;
1492                         for(node = chain->head; node; node = node->next)
1493                                 chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1494                 }
1495         }
1496
1497         if(preserve_file_stats)
1498                 set_file_stats_(chain->filename, &stats);
1499
1500         return true;
1501 }
1502
1503 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1504 {
1505         off_t current_length;
1506
1507         FLAC__ASSERT(0 != chain);
1508
1509         if (0 != chain->filename) {
1510                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1511                 return false;
1512         }
1513
1514         if (0 == callbacks.write || 0 == callbacks.seek) {
1515                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1516                 return false;
1517         }
1518
1519         if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1520                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1521                 return false;
1522         }
1523
1524         current_length = chain_prepare_for_write_(chain, use_padding);
1525
1526         /* a return value of 0 means there was an error; chain->status is already set */
1527         if (0 == current_length)
1528                 return false;
1529
1530         FLAC__ASSERT(current_length == chain->initial_length);
1531
1532         return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
1533 }
1534
1535 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)
1536 {
1537         off_t current_length;
1538
1539         FLAC__ASSERT(0 != chain);
1540
1541         if (0 != chain->filename) {
1542                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1543                 return false;
1544         }
1545
1546         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
1547                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1548                 return false;
1549         }
1550         if (0 == temp_callbacks.write) {
1551                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1552                 return false;
1553         }
1554
1555         if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1556                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1557                 return false;
1558         }
1559
1560         current_length = chain_prepare_for_write_(chain, use_padding);
1561
1562         /* a return value of 0 means there was an error; chain->status is already set */
1563         if (0 == current_length)
1564                 return false;
1565
1566         FLAC__ASSERT(current_length != chain->initial_length);
1567
1568         /* rewind */
1569         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1570                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1571                 return false;
1572         }
1573
1574         if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
1575                 return false;
1576
1577         /* recompute lengths and offsets */
1578         {
1579                 const FLAC__Metadata_Node *node;
1580                 chain->initial_length = current_length;
1581                 chain->last_offset = chain->first_offset;
1582                 for(node = chain->head; node; node = node->next)
1583                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1584         }
1585
1586         return true;
1587 }
1588
1589 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1590 {
1591         FLAC__Metadata_Node *node;
1592
1593         FLAC__ASSERT(0 != chain);
1594
1595         for(node = chain->head; node; ) {
1596                 if(!chain_merge_adjacent_padding_(chain, node))
1597                         node = node->next;
1598         }
1599 }
1600
1601 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1602 {
1603         FLAC__Metadata_Node *node, *save;
1604         unsigned i;
1605
1606         FLAC__ASSERT(0 != chain);
1607
1608         /*
1609          * Don't try and be too smart... this simple algo is good enough for
1610          * the small number of nodes that we deal with.
1611          */
1612         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1613                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1614                         save = node->next;
1615                         chain_remove_node_(chain, node);
1616                         chain_append_node_(chain, node);
1617                         node = save;
1618                 }
1619                 else {
1620                         node = node->next;
1621                 }
1622         }
1623
1624         FLAC__metadata_chain_merge_padding(chain);
1625 }
1626
1627
1628 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1629 {
1630         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1631
1632         /* calloc() implies:
1633                 iterator->current = 0;
1634                 iterator->chain = 0;
1635         */
1636
1637         return iterator;
1638 }
1639
1640 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1641 {
1642         FLAC__ASSERT(0 != iterator);
1643
1644         free(iterator);
1645 }
1646
1647 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1648 {
1649         FLAC__ASSERT(0 != iterator);
1650         FLAC__ASSERT(0 != chain);
1651         FLAC__ASSERT(0 != chain->head);
1652
1653         iterator->chain = chain;
1654         iterator->current = chain->head;
1655 }
1656
1657 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1658 {
1659         FLAC__ASSERT(0 != iterator);
1660
1661         if(0 == iterator->current || 0 == iterator->current->next)
1662                 return false;
1663
1664         iterator->current = iterator->current->next;
1665         return true;
1666 }
1667
1668 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1669 {
1670         FLAC__ASSERT(0 != iterator);
1671
1672         if(0 == iterator->current || 0 == iterator->current->prev)
1673                 return false;
1674
1675         iterator->current = iterator->current->prev;
1676         return true;
1677 }
1678
1679 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1680 {
1681         FLAC__ASSERT(0 != iterator);
1682         FLAC__ASSERT(0 != iterator->current);
1683         FLAC__ASSERT(0 != iterator->current->data);
1684
1685         return iterator->current->data->type;
1686 }
1687
1688 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1689 {
1690         FLAC__ASSERT(0 != iterator);
1691         FLAC__ASSERT(0 != iterator->current);
1692
1693         return iterator->current->data;
1694 }
1695
1696 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1697 {
1698         FLAC__ASSERT(0 != iterator);
1699         FLAC__ASSERT(0 != block);
1700         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1701 }
1702
1703 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1704 {
1705         FLAC__Metadata_Node *save;
1706
1707         FLAC__ASSERT(0 != iterator);
1708         FLAC__ASSERT(0 != iterator->current);
1709
1710         if(0 == iterator->current->prev) {
1711                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1712                 return false;
1713         }
1714
1715         save = iterator->current->prev;
1716
1717         if(replace_with_padding) {
1718                 FLAC__metadata_object_delete_data(iterator->current->data);
1719                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1720         }
1721         else {
1722                 chain_delete_node_(iterator->chain, iterator->current);
1723         }
1724
1725         iterator->current = save;
1726         return true;
1727 }
1728
1729 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1730 {
1731         FLAC__Metadata_Node *node;
1732
1733         FLAC__ASSERT(0 != iterator);
1734         FLAC__ASSERT(0 != iterator->current);
1735         FLAC__ASSERT(0 != block);
1736
1737         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1738                 return false;
1739
1740         if(0 == iterator->current->prev) {
1741                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1742                 return false;
1743         }
1744
1745         if(0 == (node = node_new_()))
1746                 return false;
1747
1748         node->data = block;
1749         iterator_insert_node_(iterator, node);
1750         iterator->current = node;
1751         return true;
1752 }
1753
1754 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1755 {
1756         FLAC__Metadata_Node *node;
1757
1758         FLAC__ASSERT(0 != iterator);
1759         FLAC__ASSERT(0 != iterator->current);
1760         FLAC__ASSERT(0 != block);
1761
1762         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1763                 return false;
1764
1765         if(0 == (node = node_new_()))
1766                 return false;
1767
1768         node->data = block;
1769         iterator_insert_node_after_(iterator, node);
1770         iterator->current = node;
1771         return true;
1772 }
1773
1774
1775 /****************************************************************************
1776  *
1777  * Local function definitions
1778  *
1779  ***************************************************************************/
1780
1781 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1782 {
1783         unsigned i;
1784
1785         b += bytes;
1786
1787         for(i = 0; i < bytes; i++) {
1788                 *(--b) = (FLAC__byte)(val & 0xff);
1789                 val >>= 8;
1790         }
1791 }
1792
1793 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1794 {
1795         unsigned i;
1796
1797         for(i = 0; i < bytes; i++) {
1798                 *(b++) = (FLAC__byte)(val & 0xff);
1799                 val >>= 8;
1800         }
1801 }
1802
1803 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1804 {
1805         unsigned i;
1806
1807         b += bytes;
1808
1809         for(i = 0; i < bytes; i++) {
1810                 *(--b) = (FLAC__byte)(val & 0xff);
1811                 val >>= 8;
1812         }
1813 }
1814
1815 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1816 {
1817         FLAC__uint32 ret = 0;
1818         unsigned i;
1819
1820         for(i = 0; i < bytes; i++)
1821                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1822
1823         return ret;
1824 }
1825
1826 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1827 {
1828         FLAC__uint32 ret = 0;
1829         unsigned i;
1830
1831         b += bytes;
1832
1833         for(i = 0; i < bytes; i++)
1834                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1835
1836         return ret;
1837 }
1838
1839 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1840 {
1841         FLAC__uint64 ret = 0;
1842         unsigned i;
1843
1844         for(i = 0; i < bytes; i++)
1845                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1846
1847         return ret;
1848 }
1849
1850 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1851 {
1852         FLAC__ASSERT(0 != iterator);
1853         FLAC__ASSERT(0 != iterator->file);
1854
1855         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1856                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1857                 return false;
1858         }
1859
1860         return true;
1861 }
1862
1863 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
1864 {
1865         FLAC__ASSERT(0 != iterator);
1866         FLAC__ASSERT(0 != iterator->file);
1867
1868         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
1869
1870         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
1871 }
1872
1873 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
1874 {
1875         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
1876
1877         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
1878                 return false;
1879
1880         *is_last = raw_header[0] & 0x80? true : false;
1881         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
1882         *length = unpack_uint32_(raw_header + 1, 3);
1883
1884         /* Note that we don't check:
1885          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
1886          * we just will read in an opaque block
1887          */
1888
1889         return true;
1890 }
1891
1892 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
1893 {
1894         switch(block->type) {
1895                 case FLAC__METADATA_TYPE_STREAMINFO:
1896                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
1897                 case FLAC__METADATA_TYPE_PADDING:
1898                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
1899                 case FLAC__METADATA_TYPE_APPLICATION:
1900                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
1901                 case FLAC__METADATA_TYPE_SEEKTABLE:
1902                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
1903                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
1904                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
1905                 case FLAC__METADATA_TYPE_CUESHEET:
1906                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
1907                 case FLAC__METADATA_TYPE_PICTURE:
1908                         return read_metadata_block_data_picture_cb_(handle, read_cb, &block->data.picture);
1909                 default:
1910                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
1911         }
1912 }
1913
1914 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
1915 {
1916         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
1917
1918         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
1919                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1920
1921         b = buffer;
1922
1923         /* we are using hardcoded numbers for simplicity but we should
1924          * probably eventually write a bit-level unpacker and use the
1925          * _STREAMINFO_ constants.
1926          */
1927         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
1928         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
1929         block->min_framesize = unpack_uint32_(b, 3); b += 3;
1930         block->max_framesize = unpack_uint32_(b, 3); b += 3;
1931         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
1932         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
1933         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
1934         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
1935         memcpy(block->md5sum, b+8, 16);
1936
1937         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1938 }
1939
1940 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
1941 {
1942         (void)block; /* nothing to do; we don't care about reading the padding bytes */
1943
1944         if(0 != seek_cb(handle, block_length, SEEK_CUR))
1945                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
1946
1947         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1948 }
1949
1950 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
1951 {
1952         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
1953
1954         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
1955                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1956
1957         block_length -= id_bytes;
1958
1959         if(block_length == 0) {
1960                 block->data = 0;
1961         }
1962         else {
1963                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
1964                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1965
1966                 if(read_cb(block->data, 1, block_length, handle) != block_length)
1967                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1968         }
1969
1970         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1971 }
1972
1973 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
1974 {
1975         unsigned i;
1976         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
1977
1978         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
1979
1980         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
1981
1982         if(block->num_points == 0)
1983                 block->points = 0;
1984         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
1985                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
1986
1987         for(i = 0; i < block->num_points; i++) {
1988                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
1989                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1990                 /* some MAGIC NUMBERs here */
1991                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
1992                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
1993                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
1994         }
1995
1996         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
1997 }
1998
1999 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
2000 {
2001         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2002         FLAC__byte buffer[4]; /* magic number is asserted below */
2003
2004         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == sizeof(buffer));
2005
2006         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2007                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2008         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
2009
2010         if(0 != entry->entry)
2011                 free(entry->entry);
2012
2013         if(entry->length == 0) {
2014                 entry->entry = 0;
2015         }
2016         else {
2017                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length+1)))
2018                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2019
2020                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
2021                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2022
2023                 entry->entry[entry->length] = '\0';
2024         }
2025
2026         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2027 }
2028
2029 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
2030 {
2031         unsigned i;
2032         FLAC__Metadata_SimpleIteratorStatus status;
2033         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2034         FLAC__byte buffer[4]; /* magic number is asserted below */
2035
2036         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == sizeof(buffer));
2037
2038         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
2039                 return status;
2040
2041         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2042                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2043         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
2044
2045         if(block->num_comments == 0) {
2046                 block->comments = 0;
2047         }
2048         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
2049                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2050
2051         for(i = 0; i < block->num_comments; i++) {
2052                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
2053                         return status;
2054         }
2055
2056         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2057 }
2058
2059 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
2060 {
2061         unsigned i, len;
2062         FLAC__byte buffer[32]; /* asserted below that this is big enough */
2063
2064         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2065         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2066         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);
2067
2068         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2069         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2070         if(read_cb(buffer, 1, len, handle) != len)
2071                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2072         track->offset = unpack_uint64_(buffer, len);
2073
2074         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2075         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2076         if(read_cb(buffer, 1, len, handle) != len)
2077                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2078         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
2079
2080         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2081         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2082         if(read_cb(track->isrc, 1, len, handle) != len)
2083                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2084
2085         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);
2086         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2087         if(read_cb(buffer, 1, len, handle) != len)
2088                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2089         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
2090         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
2091         track->type = buffer[0] >> 7;
2092         track->pre_emphasis = (buffer[0] >> 6) & 1;
2093
2094         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2095         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2096         if(read_cb(buffer, 1, len, handle) != len)
2097                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2098         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
2099
2100         if(track->num_indices == 0) {
2101                 track->indices = 0;
2102         }
2103         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
2104                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2105
2106         for(i = 0; i < track->num_indices; i++) {
2107                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2108                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2109                 if(read_cb(buffer, 1, len, handle) != len)
2110                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2111                 track->indices[i].offset = unpack_uint64_(buffer, len);
2112
2113                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2114                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2115                 if(read_cb(buffer, 1, len, handle) != len)
2116                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2117                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
2118
2119                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2120                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2121                 if(read_cb(buffer, 1, len, handle) != len)
2122                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2123         }
2124
2125         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2126 }
2127
2128 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
2129 {
2130         unsigned i, len;
2131         FLAC__Metadata_SimpleIteratorStatus status;
2132         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
2133
2134         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
2135         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
2136
2137         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2138         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2139         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
2140                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2141
2142         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2143         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2144         if(read_cb(buffer, 1, len, handle) != len)
2145                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2146         block->lead_in = unpack_uint64_(buffer, len);
2147
2148         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2149         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2150         if(read_cb(buffer, 1, len, handle) != len)
2151                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2152         block->is_cd = buffer[0]&0x80? true : false;
2153
2154         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2155         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2156         if(read_cb(buffer, 1, len, handle) != len)
2157                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2158         block->num_tracks = unpack_uint32_(buffer, len);
2159
2160         if(block->num_tracks == 0) {
2161                 block->tracks = 0;
2162         }
2163         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
2164                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2165
2166         for(i = 0; i < block->num_tracks; i++) {
2167                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
2168                         return status;
2169         }
2170
2171         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2172 }
2173
2174 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)
2175 {
2176         FLAC__byte buffer[sizeof(FLAC__uint32)];
2177
2178         FLAC__ASSERT(0 != data);
2179         FLAC__ASSERT(length_len%8 == 0);
2180
2181         length_len /= 8; /* convert to bytes */
2182
2183         FLAC__ASSERT(sizeof(buffer) >= length_len);
2184
2185         if(read_cb(buffer, 1, length_len, handle) != length_len)
2186                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2187         *length = unpack_uint32_(buffer, length_len);
2188
2189         if(0 != *data)
2190                 free(*data);
2191
2192         if(0 == (*data = (FLAC__byte*)malloc(*length+1)))
2193                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2194
2195         if(*length > 0) {
2196                 if(read_cb(*data, 1, *length, handle) != *length)
2197                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2198         }
2199
2200         (*data)[*length] = '\0';
2201
2202         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2203 }
2204
2205 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block)
2206 {
2207         FLAC__Metadata_SimpleIteratorStatus status;
2208         FLAC__byte buffer[4]; /* asserted below that this is big enough */
2209         FLAC__uint32 len;
2210
2211         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2212         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2213         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2214         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2215         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
2216
2217         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_TYPE_LEN % 8 == 0);
2218         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN / 8;
2219         if(read_cb(buffer, 1, len, handle) != len)
2220                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2221         block->type = (FLAC__StreamMetadata_Picture_Type)unpack_uint32_(buffer, len);
2222
2223         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)
2224                 return status;
2225
2226         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)
2227                 return status;
2228
2229         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN % 8 == 0);
2230         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN / 8;
2231         if(read_cb(buffer, 1, len, handle) != len)
2232                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2233         block->width = unpack_uint32_(buffer, len);
2234
2235         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN % 8 == 0);
2236         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN / 8;
2237         if(read_cb(buffer, 1, len, handle) != len)
2238                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2239         block->height = unpack_uint32_(buffer, len);
2240
2241         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN % 8 == 0);
2242         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN / 8;
2243         if(read_cb(buffer, 1, len, handle) != len)
2244                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2245         block->depth = unpack_uint32_(buffer, len);
2246
2247         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_COLORS_LEN % 8 == 0);
2248         len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN / 8;
2249         if(read_cb(buffer, 1, len, handle) != len)
2250                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2251         block->colors = unpack_uint32_(buffer, len);
2252
2253         /* for convenience we use read_metadata_block_data_picture_cstring_cb_() even though it adds an extra terminating NUL we don't use */
2254         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)
2255                 return status;
2256
2257         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2258 }
2259
2260 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2261 {
2262         if(block_length == 0) {
2263                 block->data = 0;
2264         }
2265         else {
2266                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2267                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2268
2269                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2270                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2271         }
2272
2273         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2274 }
2275
2276 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2277 {
2278         FLAC__ASSERT(0 != file);
2279         FLAC__ASSERT(0 != status);
2280
2281         if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2282                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2283                 return false;
2284         }
2285
2286         return true;
2287 }
2288
2289 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2290 {
2291         FLAC__ASSERT(0 != file);
2292         FLAC__ASSERT(0 != status);
2293
2294         if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2295                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2296                 return true;
2297         }
2298         else {
2299                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2300                 return false;
2301         }
2302 }
2303
2304 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2305 {
2306         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
2307
2308         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
2309
2310         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
2311         pack_uint32_(block->length, buffer + 1, 3);
2312
2313         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2314                 return false;
2315
2316         return true;
2317 }
2318
2319 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2320 {
2321         FLAC__ASSERT(0 != block);
2322
2323         switch(block->type) {
2324                 case FLAC__METADATA_TYPE_STREAMINFO:
2325                         return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
2326                 case FLAC__METADATA_TYPE_PADDING:
2327                         return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
2328                 case FLAC__METADATA_TYPE_APPLICATION:
2329                         return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
2330                 case FLAC__METADATA_TYPE_SEEKTABLE:
2331                         return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
2332                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2333                         return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
2334                 case FLAC__METADATA_TYPE_CUESHEET:
2335                         return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
2336                 case FLAC__METADATA_TYPE_PICTURE:
2337                         return write_metadata_block_data_picture_cb_(handle, write_cb, &block->data.picture);
2338                 default:
2339                         return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
2340         }
2341 }
2342
2343 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
2344 {
2345         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
2346         const unsigned channels1 = block->channels - 1;
2347         const unsigned bps1 = block->bits_per_sample - 1;
2348
2349         /* we are using hardcoded numbers for simplicity but we should
2350          * probably eventually write a bit-level packer and use the
2351          * _STREAMINFO_ constants.
2352          */
2353         pack_uint32_(block->min_blocksize, buffer, 2);
2354         pack_uint32_(block->max_blocksize, buffer+2, 2);
2355         pack_uint32_(block->min_framesize, buffer+4, 3);
2356         pack_uint32_(block->max_framesize, buffer+7, 3);
2357         buffer[10] = (block->sample_rate >> 12) & 0xff;
2358         buffer[11] = (block->sample_rate >> 4) & 0xff;
2359         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
2360         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
2361         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
2362         memcpy(buffer+18, block->md5sum, 16);
2363
2364         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2365                 return false;
2366
2367         return true;
2368 }
2369
2370 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
2371 {
2372         unsigned i, n = block_length;
2373         FLAC__byte buffer[1024];
2374
2375         (void)block;
2376
2377         memset(buffer, 0, 1024);
2378
2379         for(i = 0; i < n/1024; i++)
2380                 if(write_cb(buffer, 1, 1024, handle) != 1024)
2381                         return false;
2382
2383         n %= 1024;
2384
2385         if(write_cb(buffer, 1, n, handle) != n)
2386                 return false;
2387
2388         return true;
2389 }
2390
2391 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
2392 {
2393         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2394
2395         if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
2396                 return false;
2397
2398         block_length -= id_bytes;
2399
2400         if(write_cb(block->data, 1, block_length, handle) != block_length)
2401                 return false;
2402
2403         return true;
2404 }
2405
2406 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
2407 {
2408         unsigned i;
2409         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2410
2411         for(i = 0; i < block->num_points; i++) {
2412                 /* some MAGIC NUMBERs here */
2413                 pack_uint64_(block->points[i].sample_number, buffer, 8);
2414                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
2415                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
2416                 if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2417                         return false;
2418         }
2419
2420         return true;
2421 }
2422
2423 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
2424 {
2425         unsigned i;
2426         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2427         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2428         FLAC__byte buffer[4]; /* magic number is asserted below */
2429
2430         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == sizeof(buffer));
2431
2432         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
2433         if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2434                 return false;
2435         if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
2436                 return false;
2437
2438         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
2439         if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2440                 return false;
2441
2442         for(i = 0; i < block->num_comments; i++) {
2443                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
2444                 if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2445                         return false;
2446                 if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
2447                         return false;
2448         }
2449
2450         return true;
2451 }
2452
2453 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
2454 {
2455         unsigned i, j, len;
2456         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
2457
2458         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2459         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
2460         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);
2461         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2462
2463         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2464         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2465         if(write_cb(block->media_catalog_number, 1, len, handle) != len)
2466                 return false;
2467
2468         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2469         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2470         pack_uint64_(block->lead_in, buffer, len);
2471         if(write_cb(buffer, 1, len, handle) != len)
2472                 return false;
2473
2474         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2475         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2476         memset(buffer, 0, len);
2477         if(block->is_cd)
2478                 buffer[0] |= 0x80;
2479         if(write_cb(buffer, 1, len, handle) != len)
2480                 return false;
2481
2482         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2483         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2484         pack_uint32_(block->num_tracks, buffer, len);
2485         if(write_cb(buffer, 1, len, handle) != len)
2486                 return false;
2487
2488         for(i = 0; i < block->num_tracks; i++) {
2489                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
2490
2491                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2492                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2493                 pack_uint64_(track->offset, buffer, len);
2494                 if(write_cb(buffer, 1, len, handle) != len)
2495                         return false;
2496
2497                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2498                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2499                 pack_uint32_(track->number, buffer, len);
2500                 if(write_cb(buffer, 1, len, handle) != len)
2501                         return false;
2502
2503                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2504                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2505                 if(write_cb(track->isrc, 1, len, handle) != len)
2506                         return false;
2507
2508                 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);
2509                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2510                 memset(buffer, 0, len);
2511                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
2512                 if(write_cb(buffer, 1, len, handle) != len)
2513                         return false;
2514
2515                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2516                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2517                 pack_uint32_(track->num_indices, buffer, len);
2518                 if(write_cb(buffer, 1, len, handle) != len)
2519                         return false;
2520
2521                 for(j = 0; j < track->num_indices; j++) {
2522                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
2523
2524                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2525                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2526                         pack_uint64_(index->offset, buffer, len);
2527                         if(write_cb(buffer, 1, len, handle) != len)
2528                                 return false;
2529
2530                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2531                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2532                         pack_uint32_(index->number, buffer, len);
2533                         if(write_cb(buffer, 1, len, handle) != len)
2534                                 return false;
2535
2536                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2537                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2538                         memset(buffer, 0, len);
2539                         if(write_cb(buffer, 1, len, handle) != len)
2540                                 return false;
2541                 }
2542         }
2543
2544         return true;
2545 }
2546
2547 FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block)
2548 {
2549         unsigned len;
2550         size_t slen;
2551         FLAC__byte buffer[4]; /* magic number is asserted below */
2552
2553         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_TYPE_LEN%8);
2554         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN%8);
2555         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN%8);
2556         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN%8);
2557         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN%8);
2558         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN%8);
2559         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_COLORS_LEN%8);
2560         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN%8);
2561         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2562         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8);
2563         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8);
2564         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2565         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2566         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2567         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
2568         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8);
2569
2570         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8;
2571         pack_uint32_(block->type, buffer, len);
2572         if(write_cb(buffer, 1, len, handle) != len)
2573                 return false;
2574
2575         len = FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8;
2576         slen = strlen(block->mime_type);
2577         pack_uint32_(slen, buffer, len);
2578         if(write_cb(buffer, 1, len, handle) != len)
2579                 return false;
2580         if(write_cb(block->mime_type, 1, slen, handle) != slen)
2581                 return false;
2582
2583         len = FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8;
2584         slen = strlen((const char *)block->description);
2585         pack_uint32_(slen, buffer, len);
2586         if(write_cb(buffer, 1, len, handle) != len)
2587                 return false;
2588         if(write_cb(block->description, 1, slen, handle) != slen)
2589                 return false;
2590
2591         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8;
2592         pack_uint32_(block->width, buffer, len);
2593         if(write_cb(buffer, 1, len, handle) != len)
2594                 return false;
2595
2596         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8;
2597         pack_uint32_(block->height, buffer, len);
2598         if(write_cb(buffer, 1, len, handle) != len)
2599                 return false;
2600
2601         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8;
2602         pack_uint32_(block->depth, buffer, len);
2603         if(write_cb(buffer, 1, len, handle) != len)
2604                 return false;
2605
2606         len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8;
2607         pack_uint32_(block->colors, buffer, len);
2608         if(write_cb(buffer, 1, len, handle) != len)
2609                 return false;
2610
2611         len = FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8;
2612         pack_uint32_(block->data_length, buffer, len);
2613         if(write_cb(buffer, 1, len, handle) != len)
2614                 return false;
2615         if(write_cb(block->data, 1, block->data_length, handle) != block->data_length)
2616                 return false;
2617
2618         return true;
2619 }
2620
2621 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2622 {
2623         if(write_cb(block->data, 1, block_length, handle) != block_length)
2624                 return false;
2625
2626         return true;
2627 }
2628
2629 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2630 {
2631         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2632                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2633                 return false;
2634         }
2635
2636         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2637                 return false;
2638
2639         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2640                 return false;
2641
2642         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2643                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2644                 return false;
2645         }
2646
2647         return read_metadata_block_header_(iterator);
2648 }
2649
2650 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2651 {
2652         FLAC__StreamMetadata *padding;
2653
2654         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2655                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2656                 return false;
2657         }
2658
2659         block->is_last = false;
2660
2661         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2662                 return false;
2663
2664         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2665                 return false;
2666
2667         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2668                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2669
2670         padding->is_last = padding_is_last;
2671         padding->length = padding_length;
2672
2673         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2674                 FLAC__metadata_object_delete(padding);
2675                 return false;
2676         }
2677
2678         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2679                 FLAC__metadata_object_delete(padding);
2680                 return false;
2681         }
2682
2683         FLAC__metadata_object_delete(padding);
2684
2685         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2686                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2687                 return false;
2688         }
2689
2690         return read_metadata_block_header_(iterator);
2691 }
2692
2693 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2694 {
2695         FILE *tempfile;
2696         char *tempfilename;
2697         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2698         off_t fixup_is_last_flag_offset = -1;
2699
2700         FLAC__ASSERT(0 != block || append == false);
2701
2702         if(iterator->is_last) {
2703                 if(append) {
2704                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2705                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2706                 }
2707                 else if(0 == block) {
2708                         simple_iterator_push_(iterator);
2709                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2710                                 (void)simple_iterator_pop_(iterator);
2711                                 return false;
2712                         }
2713                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2714                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2715                         if(!simple_iterator_pop_(iterator))
2716                                 return false;
2717                 }
2718         }
2719
2720         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2721                 return false;
2722
2723         if(0 != block) {
2724                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2725                         cleanup_tempfile_(&tempfile, &tempfilename);
2726                         return false;
2727                 }
2728
2729                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2730                         cleanup_tempfile_(&tempfile, &tempfilename);
2731                         return false;
2732                 }
2733         }
2734
2735         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2736                 return false;
2737
2738         if(append)
2739                 return FLAC__metadata_simple_iterator_next(iterator);
2740
2741         return true;
2742 }
2743
2744 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2745 {
2746         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2747         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2748         iterator->depth++;
2749 }
2750
2751 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2752 {
2753         FLAC__ASSERT(iterator->depth > 0);
2754         iterator->depth--;
2755         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2756                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2757                 return false;
2758         }
2759
2760         return read_metadata_block_header_(iterator);
2761 }
2762
2763 /* return meanings:
2764  * 0: ok
2765  * 1: read error
2766  * 2: seek error
2767  * 3: not a FLAC file
2768  */
2769 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2770 {
2771         FLAC__byte buffer[4];
2772         size_t n;
2773         unsigned i;
2774
2775         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == sizeof(buffer));
2776
2777         /* skip any id3v2 tag */
2778         errno = 0;
2779         n = read_cb(buffer, 1, 4, handle);
2780         if(errno)
2781                 return 1;
2782         else if(n != 4)
2783                 return 3;
2784         else if(0 == memcmp(buffer, "ID3", 3)) {
2785                 unsigned tag_length = 0;
2786
2787                 /* skip to the tag length */
2788                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2789                         return 2;
2790
2791                 /* read the length */
2792                 for(i = 0; i < 4; i++) {
2793                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2794                                 return 1;
2795                         tag_length <<= 7;
2796                         tag_length |= (buffer[0] & 0x7f);
2797                 }
2798
2799                 /* skip the rest of the tag */
2800                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2801                         return 2;
2802
2803                 /* read the stream sync code */
2804                 errno = 0;
2805                 n = read_cb(buffer, 1, 4, handle);
2806                 if(errno)
2807                         return 1;
2808                 else if(n != 4)
2809                         return 3;
2810         }
2811
2812         /* check for the fLaC signature */
2813         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2814                 return 0;
2815         else
2816                 return 3;
2817 }
2818
2819 unsigned seek_to_first_metadata_block_(FILE *f)
2820 {
2821         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2822 }
2823
2824 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2825 {
2826         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];
2827
2828         if(0 != fseeko(iterator->file, 0, SEEK_SET)) {
2829                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2830                 return false;
2831         }
2832         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2833                 cleanup_tempfile_(tempfile, tempfilename);
2834                 return false;
2835         }
2836         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2837                 cleanup_tempfile_(tempfile, tempfilename);
2838                 return false;
2839         }
2840
2841         return true;
2842 }
2843
2844 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)
2845 {
2846         off_t save_offset = iterator->offset[iterator->depth];
2847         FLAC__ASSERT(0 != *tempfile);
2848
2849         if(0 != fseeko(iterator->file, save_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length, SEEK_SET)) {
2850                 cleanup_tempfile_(tempfile, tempfilename);
2851                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2852                 return false;
2853         }
2854         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2855                 cleanup_tempfile_(tempfile, tempfilename);
2856                 return false;
2857         }
2858
2859         if(fixup_is_last_code != 0) {
2860                 /*
2861                  * if code == 1, it means a block was appended to the end so
2862                  *   we have to clear the is_last flag of the previous block
2863                  * if code == -1, it means the last block was deleted so
2864                  *   we have to set the is_last flag of the previous block
2865                  */
2866                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
2867                 FLAC__byte x;
2868                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2869                         cleanup_tempfile_(tempfile, tempfilename);
2870                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2871                         return false;
2872                 }
2873                 if(fread(&x, 1, 1, *tempfile) != 1) {
2874                         cleanup_tempfile_(tempfile, tempfilename);
2875                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2876                         return false;
2877                 }
2878                 if(fixup_is_last_code > 0) {
2879                         FLAC__ASSERT(x & 0x80);
2880                         x &= 0x7f;
2881                 }
2882                 else {
2883                         FLAC__ASSERT(!(x & 0x80));
2884                         x |= 0x80;
2885                 }
2886                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
2887                         cleanup_tempfile_(tempfile, tempfilename);
2888                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2889                         return false;
2890                 }
2891                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
2892                         cleanup_tempfile_(tempfile, tempfilename);
2893                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2894                         return false;
2895                 }
2896         }
2897
2898         (void)fclose(iterator->file);
2899
2900         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
2901                 return false;
2902
2903         if(iterator->has_stats)
2904                 set_file_stats_(iterator->filename, &iterator->stats);
2905
2906         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
2907                 return false;
2908         if(backup) {
2909                 while(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length < save_offset)
2910                         if(!FLAC__metadata_simple_iterator_next(iterator))
2911                                 return false;
2912                 return true;
2913         }
2914         else {
2915                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
2916                 FLAC__ASSERT(iterator->depth == 0);
2917                 iterator->offset[0] = save_offset;
2918                 iterator->depth++;
2919                 return simple_iterator_pop_(iterator);
2920         }
2921 }
2922
2923 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
2924 {
2925         FLAC__byte buffer[8192];
2926         size_t n;
2927
2928         while(bytes > 0) {
2929                 n = min(sizeof(buffer), bytes);
2930                 if(fread(buffer, 1, n, file) != n) {
2931                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2932                         return false;
2933                 }
2934                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
2935                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2936                         return false;
2937                 }
2938                 bytes -= n;
2939         }
2940
2941         return true;
2942 }
2943
2944 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)
2945 {
2946         FLAC__byte buffer[8192];
2947         size_t n;
2948
2949         while(bytes > 0) {
2950                 n = min(sizeof(buffer), bytes);
2951                 if(read_cb(buffer, 1, n, handle) != n) {
2952                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2953                         return false;
2954                 }
2955                 if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
2956                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2957                         return false;
2958                 }
2959                 bytes -= n;
2960         }
2961
2962         return true;
2963 }
2964
2965 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
2966 {
2967         FLAC__byte buffer[8192];
2968         size_t n;
2969
2970         while(!feof(file)) {
2971                 n = fread(buffer, 1, sizeof(buffer), file);
2972                 if(n == 0 && !feof(file)) {
2973                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2974                         return false;
2975                 }
2976                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
2977                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2978                         return false;
2979                 }
2980         }
2981
2982         return true;
2983 }
2984
2985 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)
2986 {
2987         FLAC__byte buffer[8192];
2988         size_t n;
2989
2990         while(!eof_cb(handle)) {
2991                 n = read_cb(buffer, 1, sizeof(buffer), handle);
2992                 if(n == 0 && !eof_cb(handle)) {
2993                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2994                         return false;
2995                 }
2996                 if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
2997                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2998                         return false;
2999                 }
3000         }
3001
3002         return true;
3003 }
3004
3005 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
3006 {
3007         static const char *tempfile_suffix = ".metadata_edit";
3008         if(0 == tempfile_path_prefix) {
3009                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
3010                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
3011                         return false;
3012                 }
3013                 strcpy(*tempfilename, filename);
3014                 strcat(*tempfilename, tempfile_suffix);
3015         }
3016         else {
3017                 const char *p = strrchr(filename, '/');
3018                 if(0 == p)
3019                         p = filename;
3020                 else
3021                         p++;
3022
3023                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
3024                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
3025                         return false;
3026                 }
3027                 strcpy(*tempfilename, tempfile_path_prefix);
3028                 strcat(*tempfilename, "/");
3029                 strcat(*tempfilename, p);
3030                 strcat(*tempfilename, tempfile_suffix);
3031         }
3032
3033         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
3034                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
3035                 return false;
3036         }
3037
3038         return true;
3039 }
3040
3041 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
3042 {
3043         FLAC__ASSERT(0 != filename);
3044         FLAC__ASSERT(0 != tempfile);
3045         FLAC__ASSERT(0 != *tempfile);
3046         FLAC__ASSERT(0 != tempfilename);
3047         FLAC__ASSERT(0 != *tempfilename);
3048         FLAC__ASSERT(0 != status);
3049
3050         (void)fclose(*tempfile);
3051         *tempfile = 0;
3052
3053 #if defined _MSC_VER || defined __MINGW32__ || defined __EMX__
3054         /* on some flavors of windows, rename() will fail if the destination already exists */
3055         if(unlink(filename) < 0) {
3056                 cleanup_tempfile_(tempfile, tempfilename);
3057                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
3058                 return false;
3059         }
3060 #endif
3061
3062         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
3063         if(0 != rename(*tempfilename, filename)) {
3064                 cleanup_tempfile_(tempfile, tempfilename);
3065                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
3066                 return false;
3067         }
3068
3069         cleanup_tempfile_(tempfile, tempfilename);
3070
3071         return true;
3072 }
3073
3074 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
3075 {
3076         if(0 != *tempfile) {
3077                 (void)fclose(*tempfile);
3078                 *tempfile = 0;
3079         }
3080
3081         if(0 != *tempfilename) {
3082                 (void)unlink(*tempfilename);
3083                 free(*tempfilename);
3084                 *tempfilename = 0;
3085         }
3086 }
3087
3088 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
3089 {
3090         FLAC__ASSERT(0 != filename);
3091         FLAC__ASSERT(0 != stats);
3092         return (0 == stat(filename, stats));
3093 }
3094
3095 void set_file_stats_(const char *filename, struct stat *stats)
3096 {
3097         struct utimbuf srctime;
3098
3099         FLAC__ASSERT(0 != filename);
3100         FLAC__ASSERT(0 != stats);
3101
3102         srctime.actime = stats->st_atime;
3103         srctime.modtime = stats->st_mtime;
3104         (void)chmod(filename, stats->st_mode);
3105         (void)utime(filename, &srctime);
3106 #if !defined _MSC_VER && !defined __MINGW32__ && !defined __EMX__
3107         (void)chown(filename, stats->st_uid, -1);
3108         (void)chown(filename, -1, stats->st_gid);
3109 #endif
3110 }
3111
3112 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
3113 {
3114         return fseeko((FILE*)handle, (off_t)offset, whence);
3115 }
3116
3117 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
3118 {
3119         return ftello((FILE*)handle);
3120 }
3121
3122 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
3123 {
3124         switch(status) {
3125                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
3126                         return FLAC__METADATA_CHAIN_STATUS_OK;
3127                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
3128                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
3129                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
3130                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
3131                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
3132                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
3133                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
3134                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
3135                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
3136                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
3137                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
3138                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
3139                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
3140                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
3141                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
3142                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
3143                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
3144                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
3145                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
3146                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
3147                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
3148                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
3149                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
3150                 default:
3151                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
3152         }
3153 }