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__bool is_ogg;
 843         FLAC__Metadata_Node *head;
 844         FLAC__Metadata_Node *tail;
 845         unsigned nodes;
 846         FLAC__Metadata_ChainStatus status;
 847         off_t first_offset, last_offset;
 848         /*
 849          * This is the length of the chain initially read from the FLAC file.
 850          * it is used to compare against the current length to decide whether
 851          * or not the whole file has to be rewritten.
 852          */
 853         off_t initial_length;
 854         /* @@@ hacky, these are currently only needed by ogg reader */
 855         FLAC__IOHandle handle;
 856         FLAC__IOCallback_Read read_cb;
 857 };
 858
 859 struct FLAC__Metadata_Iterator {
 860         FLAC__Metadata_Chain *chain;
 861         FLAC__Metadata_Node *current;
 862 };
 863
 864 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 865         "FLAC__METADATA_CHAIN_STATUS_OK",
 866         "FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
 867         "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
 868         "FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
 869         "FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
 870         "FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
 871         "FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
 872         "FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
 873         "FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
 874         "FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
 875         "FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
 876         "FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
 877         "FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
 878         "FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
 879         "FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
 880         "FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
 881 };
 882
 883
 884 static FLAC__Metadata_Node *node_new_()
 885 {
 886         return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 887 }
 888
 889 static void node_delete_(FLAC__Metadata_Node *node)
 890 {
 891         FLAC__ASSERT(0 != node);
 892         if(0 != node->data)
 893                 FLAC__metadata_object_delete(node->data);
 894         free(node);
 895 }
 896
 897 static void chain_init_(FLAC__Metadata_Chain *chain)
 898 {
 899         FLAC__ASSERT(0 != chain);
 900
 901         chain->filename = 0;
 902         chain->is_ogg = false;
 903         chain->head = chain->tail = 0;
 904         chain->nodes = 0;
 905         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
 906         chain->initial_length = 0;
 907         chain->read_cb = 0;
 908 }
 909
 910 static void chain_clear_(FLAC__Metadata_Chain *chain)
 911 {
 912         FLAC__Metadata_Node *node, *next;
 913
 914         FLAC__ASSERT(0 != chain);
 915
 916         for(node = chain->head; node; ) {
 917                 next = node->next;
 918                 node_delete_(node);
 919                 node = next;
 920         }
 921
 922         if(0 != chain->filename)
 923                 free(chain->filename);
 924
 925         chain_init_(chain);
 926 }
 927
 928 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 929 {
 930         FLAC__ASSERT(0 != chain);
 931         FLAC__ASSERT(0 != node);
 932         FLAC__ASSERT(0 != node->data);
 933
 934         node->next = node->prev = 0;
 935         node->data->is_last = true;
 936         if(0 != chain->tail)
 937                 chain->tail->data->is_last = false;
 938
 939         if(0 == chain->head)
 940                 chain->head = node;
 941         else {
 942                 FLAC__ASSERT(0 != chain->tail);
 943                 chain->tail->next = node;
 944                 node->prev = chain->tail;
 945         }
 946         chain->tail = node;
 947         chain->nodes++;
 948 }
 949
 950 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 951 {
 952         FLAC__ASSERT(0 != chain);
 953         FLAC__ASSERT(0 != node);
 954
 955         if(node == chain->head)
 956                 chain->head = node->next;
 957         else
 958                 node->prev->next = node->next;
 959
 960         if(node == chain->tail)
 961                 chain->tail = node->prev;
 962         else
 963                 node->next->prev = node->prev;
 964
 965         if(0 != chain->tail)
 966                 chain->tail->data->is_last = true;
 967
 968         chain->nodes--;
 969 }
 970
 971 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
 972 {
 973         chain_remove_node_(chain, node);
 974         node_delete_(node);
 975 }
 976
 977 static off_t chain_calculate_length_(FLAC__Metadata_Chain *chain)
 978 {
 979         const FLAC__Metadata_Node *node;
 980         off_t length = 0;
 981         for(node = chain->head; node; node = node->next)
 982                 length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
 983         return length;
 984 }
 985
 986 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
 987 {
 988         FLAC__ASSERT(0 != node);
 989         FLAC__ASSERT(0 != node->data);
 990         FLAC__ASSERT(0 != iterator);
 991         FLAC__ASSERT(0 != iterator->current);
 992         FLAC__ASSERT(0 != iterator->chain);
 993         FLAC__ASSERT(0 != iterator->chain->head);
 994         FLAC__ASSERT(0 != iterator->chain->tail);
 995
 996         node->data->is_last = false;
 997
 998         node->prev = iterator->current->prev;
 999         node->next = iterator->current;
1000
1001         if(0 == node->prev)
1002                 iterator->chain->head = node;
1003         else
1004                 node->prev->next = node;
1005
1006         iterator->current->prev = node;
1007
1008         iterator->chain->nodes++;
1009 }
1010
1011 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
1012 {
1013         FLAC__ASSERT(0 != node);
1014         FLAC__ASSERT(0 != node->data);
1015         FLAC__ASSERT(0 != iterator);
1016         FLAC__ASSERT(0 != iterator->current);
1017         FLAC__ASSERT(0 != iterator->chain);
1018         FLAC__ASSERT(0 != iterator->chain->head);
1019         FLAC__ASSERT(0 != iterator->chain->tail);
1020
1021         iterator->current->data->is_last = false;
1022
1023         node->prev = iterator->current;
1024         node->next = iterator->current->next;
1025
1026         if(0 == node->next)
1027                 iterator->chain->tail = node;
1028         else
1029                 node->next->prev = node;
1030
1031         node->prev->next = node;
1032
1033         iterator->chain->tail->data->is_last = true;
1034
1035         iterator->chain->nodes++;
1036 }
1037
1038 /* return true iff node and node->next are both padding */
1039 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
1040 {
1041         if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
1042                 const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
1043                 node->data->length += growth;
1044
1045                 chain_delete_node_(chain, node->next);
1046                 return true;
1047         }
1048         else
1049                 return false;
1050 }
1051
1052 /* Returns the new length of the chain, or 0 if there was an error. */
1053 /* WATCHOUT: This can get called multiple times before a write, so
1054  * it should still work when this happens.
1055  */
1056 /* WATCHOUT: Make sure to also update the logic in
1057  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
1058  */
1059 static off_t chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1060 {
1061         off_t current_length = chain_calculate_length_(chain);
1062
1063         if(use_padding) {
1064                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1065                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1066                         const off_t delta = chain->initial_length - current_length;
1067                         chain->tail->data->length += delta;
1068                         current_length += delta;
1069                         FLAC__ASSERT(current_length == chain->initial_length);
1070                 }
1071                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1072                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
1073                         FLAC__StreamMetadata *padding;
1074                         FLAC__Metadata_Node *node;
1075                         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
1076                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1077                                 return 0;
1078                         }
1079                         padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
1080                         if(0 == (node = node_new_())) {
1081                                 FLAC__metadata_object_delete(padding);
1082                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1083                                 return 0;
1084                         }
1085                         node->data = padding;
1086                         chain_append_node_(chain, node);
1087                         current_length = chain_calculate_length_(chain);
1088                         FLAC__ASSERT(current_length == chain->initial_length);
1089                 }
1090                 /* 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 */
1091                 else if(current_length > chain->initial_length) {
1092                         const off_t delta = current_length - chain->initial_length;
1093                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1094                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1095                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
1096                                         chain_delete_node_(chain, chain->tail);
1097                                         current_length = chain_calculate_length_(chain);
1098                                         FLAC__ASSERT(current_length == chain->initial_length);
1099                                 }
1100                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1101                                 else if((off_t)chain->tail->data->length >= delta) {
1102                                         chain->tail->data->length -= delta;
1103                                         current_length -= delta;
1104                                         FLAC__ASSERT(current_length == chain->initial_length);
1105                                 }
1106                         }
1107                 }
1108         }
1109
1110         return current_length;
1111 }
1112
1113 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)
1114 {
1115         FLAC__Metadata_Node *node;
1116
1117         FLAC__ASSERT(0 != chain);
1118
1119         /* we assume we're already at the beginning of the file */
1120
1121         switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
1122                 case 0:
1123                         break;
1124                 case 1:
1125                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1126                         return false;
1127                 case 2:
1128                         chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1129                         return false;
1130                 case 3:
1131                         chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
1132                         return false;
1133                 default:
1134                         FLAC__ASSERT(0);
1135                         return false;
1136         }
1137
1138         {
1139                 FLAC__int64 pos = tell_cb(handle);
1140                 if(pos < 0) {
1141                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1142                         return false;
1143                 }
1144                 chain->first_offset = (off_t)pos;
1145         }
1146
1147         {
1148                 FLAC__bool is_last;
1149                 FLAC__MetadataType type;
1150                 unsigned length;
1151
1152                 do {
1153                         node = node_new_();
1154                         if(0 == node) {
1155                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1156                                 return false;
1157                         }
1158
1159                         if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
1160                                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1161                                 return false;
1162                         }
1163
1164                         node->data = FLAC__metadata_object_new(type);
1165                         if(0 == node->data) {
1166                                 node_delete_(node);
1167                                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1168                                 return false;
1169                         }
1170
1171                         node->data->is_last = is_last;
1172                         node->data->length = length;
1173
1174                         chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
1175                         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1176                                 node_delete_(node);
1177                                 return false;
1178                         }
1179                         chain_append_node_(chain, node);
1180                 } while(!is_last);
1181         }
1182
1183         {
1184                 FLAC__int64 pos = tell_cb(handle);
1185                 if(pos < 0) {
1186                         chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
1187                         return false;
1188                 }
1189                 chain->last_offset = (off_t)pos;
1190         }
1191
1192         chain->initial_length = chain_calculate_length_(chain);
1193
1194         return true;
1195 }
1196
1197 FLAC__StreamDecoderReadStatus chain_read_ogg_read_cb_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
1198 {
1199         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
1200         (void)decoder;
1201         if(*bytes > 0 && chain->status == FLAC__METADATA_CHAIN_STATUS_OK) {
1202                 *bytes = chain->read_cb(buffer, sizeof(FLAC__byte), *bytes, chain->handle);
1203                 if(*bytes == 0)
1204                         return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
1205                 else
1206                         return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
1207         }
1208         else
1209                 return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
1210 }
1211
1212 static FLAC__StreamDecoderWriteStatus chain_read_ogg_write_cb_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
1213 {
1214         (void)decoder, (void)frame, (void)buffer, (void)client_data;
1215         return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
1216 }
1217
1218 static void chain_read_ogg_metadata_cb_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
1219 {
1220         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
1221
1222         (void)decoder;
1223
1224         FLAC__Metadata_Node *node = node_new_();
1225         if(0 == node) {
1226                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1227                 return;
1228         }
1229
1230         node->data = FLAC__metadata_object_clone(metadata);
1231         if(0 == node->data) {
1232                 node_delete_(node);
1233                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1234                 return;
1235         }
1236
1237         chain_append_node_(chain, node);
1238 }
1239
1240 static void chain_read_ogg_error_cb_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
1241 {
1242         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
1243         (void)decoder, (void)status;
1244         chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
1245 }
1246
1247 static FLAC__bool chain_read_ogg_cb_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb)
1248 {
1249         FLAC__StreamDecoder *decoder;
1250
1251         FLAC__ASSERT(0 != chain);
1252
1253         /* we assume we're already at the beginning of the file */
1254
1255         chain->handle = handle;
1256         chain->read_cb = read_cb;
1257         if(0 == (decoder = FLAC__stream_decoder_new())) {
1258                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1259                 return false;
1260         }
1261         FLAC__stream_decoder_set_metadata_respond_all(decoder);
1262         if(FLAC__stream_decoder_init_ogg_stream(decoder, chain_read_ogg_read_cb_, /*seek_callback=*/0, /*tell_callback=*/0, /*length_callback=*/0, /*eof_callback=*/0, chain_read_ogg_write_cb_, chain_read_ogg_metadata_cb_, chain_read_ogg_error_cb_, chain) != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
1263                 FLAC__stream_decoder_delete(decoder);
1264                 chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
1265                 return false;
1266         }
1267
1268         chain->first_offset = 0; /*@@@ wrong; will need to be set correctly to implement metadata writing for Ogg FLAC */
1269
1270         if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder))
1271                 chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
1272         if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
1273                 FLAC__stream_decoder_delete(decoder);
1274                 return false;
1275         }
1276
1277         FLAC__stream_decoder_delete(decoder);
1278
1279         chain->last_offset = 0; /*@@@ wrong; will need to be set correctly to implement metadata writing for Ogg FLAC */
1280
1281         chain->initial_length = chain_calculate_length_(chain);
1282
1283         return true;
1284 }
1285
1286 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)
1287 {
1288         FLAC__Metadata_Node *node;
1289
1290         FLAC__ASSERT(0 != chain);
1291         FLAC__ASSERT(0 != chain->head);
1292
1293         if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
1294                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1295                 return false;
1296         }
1297
1298         for(node = chain->head; node; node = node->next) {
1299                 if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
1300                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1301                         return false;
1302                 }
1303                 if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
1304                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1305                         return false;
1306                 }
1307         }
1308
1309         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1310
1311         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1312         return true;
1313 }
1314
1315 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
1316 {
1317         FILE *file;
1318         FLAC__bool ret;
1319
1320         FLAC__ASSERT(0 != chain->filename);
1321
1322         if(0 == (file = fopen(chain->filename, "r+b"))) {
1323                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1324                 return false;
1325         }
1326
1327         /* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
1328         ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
1329
1330         fclose(file);
1331
1332         return ret;
1333 }
1334
1335 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
1336 {
1337         FILE *f, *tempfile;
1338         char *tempfilename;
1339         FLAC__Metadata_SimpleIteratorStatus status;
1340         const FLAC__Metadata_Node *node;
1341
1342         FLAC__ASSERT(0 != chain);
1343         FLAC__ASSERT(0 != chain->filename);
1344         FLAC__ASSERT(0 != chain->head);
1345
1346         /* copy the file prefix (data up to first metadata block */
1347         if(0 == (f = fopen(chain->filename, "rb"))) {
1348                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1349                 return false;
1350         }
1351         if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
1352                 chain->status = get_equivalent_status_(status);
1353                 cleanup_tempfile_(&tempfile, &tempfilename);
1354                 return false;
1355         }
1356         if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
1357                 chain->status = get_equivalent_status_(status);
1358                 cleanup_tempfile_(&tempfile, &tempfilename);
1359                 return false;
1360         }
1361
1362         /* write the metadata */
1363         for(node = chain->head; node; node = node->next) {
1364                 if(!write_metadata_block_header_(tempfile, &status, node->data)) {
1365                         chain->status = get_equivalent_status_(status);
1366                         return false;
1367                 }
1368                 if(!write_metadata_block_data_(tempfile, &status, node->data)) {
1369                         chain->status = get_equivalent_status_(status);
1370                         return false;
1371                 }
1372         }
1373         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1374
1375         /* copy the file postfix (everything after the metadata) */
1376         if(0 != fseeko(f, chain->last_offset, SEEK_SET)) {
1377                 cleanup_tempfile_(&tempfile, &tempfilename);
1378                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1379                 return false;
1380         }
1381         if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
1382                 cleanup_tempfile_(&tempfile, &tempfilename);
1383                 chain->status = get_equivalent_status_(status);
1384                 return false;
1385         }
1386
1387         /* move the tempfile on top of the original */
1388         (void)fclose(f);
1389         if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
1390                 return false;
1391
1392         return true;
1393 }
1394
1395 /* assumes 'handle' is already at beginning of file */
1396 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)
1397 {
1398         FLAC__Metadata_SimpleIteratorStatus status;
1399         const FLAC__Metadata_Node *node;
1400
1401         FLAC__ASSERT(0 != chain);
1402         FLAC__ASSERT(0 == chain->filename);
1403         FLAC__ASSERT(0 != chain->head);
1404
1405         /* copy the file prefix (data up to first metadata block */
1406         if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
1407                 chain->status = get_equivalent_status_(status);
1408                 return false;
1409         }
1410
1411         /* write the metadata */
1412         for(node = chain->head; node; node = node->next) {
1413                 if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
1414                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1415                         return false;
1416                 }
1417                 if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
1418                         chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
1419                         return false;
1420                 }
1421         }
1422         /*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
1423
1424         /* copy the file postfix (everything after the metadata) */
1425         if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
1426                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1427                 return false;
1428         }
1429         if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
1430                 chain->status = get_equivalent_status_(status);
1431                 return false;
1432         }
1433
1434         return true;
1435 }
1436
1437 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new()
1438 {
1439         FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)calloc(1, sizeof(FLAC__Metadata_Chain));
1440
1441         if(0 != chain)
1442                 chain_init_(chain);
1443
1444         return chain;
1445 }
1446
1447 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
1448 {
1449         FLAC__ASSERT(0 != chain);
1450
1451         chain_clear_(chain);
1452
1453         free(chain);
1454 }
1455
1456 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
1457 {
1458         FLAC__Metadata_ChainStatus status;
1459
1460         FLAC__ASSERT(0 != chain);
1461
1462         status = chain->status;
1463         chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
1464         return status;
1465 }
1466
1467 static FLAC__bool chain_read_(FLAC__Metadata_Chain *chain, const char *filename, FLAC__bool is_ogg)
1468 {
1469         FILE *file;
1470         FLAC__bool ret;
1471
1472         FLAC__ASSERT(0 != chain);
1473         FLAC__ASSERT(0 != filename);
1474
1475         chain_clear_(chain);
1476
1477         if(0 == (chain->filename = strdup(filename))) {
1478                 chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
1479                 return false;
1480         }
1481
1482         chain->is_ogg = is_ogg;
1483
1484         if(0 == (file = fopen(filename, "rb"))) {
1485                 chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
1486                 return false;
1487         }
1488
1489         /* the function also sets chain->status for us */
1490         ret = is_ogg?
1491                 chain_read_ogg_cb_(chain, file, (FLAC__IOCallback_Read)fread) :
1492                 chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_)
1493         ;
1494
1495         fclose(file);
1496
1497         return ret;
1498 }
1499
1500 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
1501 {
1502         return chain_read_(chain, filename, /*is_ogg=*/false);
1503 }
1504
1505 FLAC_API FLAC__bool FLAC__metadata_chain_read_ogg(FLAC__Metadata_Chain *chain, const char *filename)
1506 {
1507         return chain_read_(chain, filename, /*is_ogg=*/true);
1508 }
1509
1510 static FLAC__bool chain_read_with_callbacks_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks, FLAC__bool is_ogg)
1511 {
1512         FLAC__bool ret;
1513
1514         FLAC__ASSERT(0 != chain);
1515
1516         chain_clear_(chain);
1517
1518         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
1519                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1520                 return false;
1521         }
1522
1523         chain->is_ogg = is_ogg;
1524
1525         /* rewind */
1526         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1527                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1528                 return false;
1529         }
1530
1531         /* the function also sets chain->status for us */
1532         ret = is_ogg?
1533                 chain_read_ogg_cb_(chain, handle, callbacks.read) :
1534                 chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell)
1535         ;
1536
1537         return ret;
1538 }
1539
1540 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1541 {
1542         return chain_read_with_callbacks_(chain, handle, callbacks, /*is_ogg=*/false);
1543 }
1544
1545 FLAC_API FLAC__bool FLAC__metadata_chain_read_ogg_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1546 {
1547         return chain_read_with_callbacks_(chain, handle, callbacks, /*is_ogg=*/true);
1548 }
1549
1550 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
1551 {
1552         /* This does all the same checks that are in chain_prepare_for_write_()
1553          * but doesn't actually alter the chain.  Make sure to update the logic
1554          * here if chain_prepare_for_write_() changes.
1555          */
1556         const off_t current_length = chain_calculate_length_(chain);
1557
1558         FLAC__ASSERT(0 != chain);
1559
1560         if(use_padding) {
1561                 /* if the metadata shrank and the last block is padding, we just extend the last padding block */
1562                 if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING)
1563                         return false;
1564                 /* if the metadata shrank more than 4 bytes then there's room to add another padding block */
1565                 else if(current_length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length)
1566                         return false;
1567                 /* 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 */
1568                 else if(current_length > chain->initial_length) {
1569                         const off_t delta = current_length - chain->initial_length;
1570                         if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
1571                                 /* if the delta is exactly the size of the last padding block, remove the padding block */
1572                                 if((off_t)chain->tail->data->length + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta)
1573                                         return false;
1574                                 /* if there is at least 'delta' bytes of padding, trim the padding down */
1575                                 else if((off_t)chain->tail->data->length >= delta)
1576                                         return false;
1577                         }
1578                 }
1579         }
1580
1581         return (current_length != chain->initial_length);
1582 }
1583
1584 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
1585 {
1586         struct stat stats;
1587         const char *tempfile_path_prefix = 0;
1588         off_t current_length;
1589
1590         FLAC__ASSERT(0 != chain);
1591
1592         if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
1593                 chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
1594                 return false;
1595         }
1596
1597         if (0 == chain->filename) {
1598                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1599                 return false;
1600         }
1601
1602         current_length = chain_prepare_for_write_(chain, use_padding);
1603
1604         /* a return value of 0 means there was an error; chain->status is already set */
1605         if (0 == current_length)
1606                 return false;
1607
1608         if(preserve_file_stats)
1609                 get_file_stats_(chain->filename, &stats);
1610
1611         if(current_length == chain->initial_length) {
1612                 if(!chain_rewrite_metadata_in_place_(chain))
1613                         return false;
1614         }
1615         else {
1616                 if(!chain_rewrite_file_(chain, tempfile_path_prefix))
1617                         return false;
1618
1619                 /* recompute lengths and offsets */
1620                 {
1621                         const FLAC__Metadata_Node *node;
1622                         chain->initial_length = current_length;
1623                         chain->last_offset = chain->first_offset;
1624                         for(node = chain->head; node; node = node->next)
1625                                 chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1626                 }
1627         }
1628
1629         if(preserve_file_stats)
1630                 set_file_stats_(chain->filename, &stats);
1631
1632         return true;
1633 }
1634
1635 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
1636 {
1637         off_t current_length;
1638
1639         FLAC__ASSERT(0 != chain);
1640
1641         if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
1642                 chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
1643                 return false;
1644         }
1645
1646         if (0 != chain->filename) {
1647                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1648                 return false;
1649         }
1650
1651         if (0 == callbacks.write || 0 == callbacks.seek) {
1652                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1653                 return false;
1654         }
1655
1656         if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1657                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1658                 return false;
1659         }
1660
1661         current_length = chain_prepare_for_write_(chain, use_padding);
1662
1663         /* a return value of 0 means there was an error; chain->status is already set */
1664         if (0 == current_length)
1665                 return false;
1666
1667         FLAC__ASSERT(current_length == chain->initial_length);
1668
1669         return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
1670 }
1671
1672 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)
1673 {
1674         off_t current_length;
1675
1676         FLAC__ASSERT(0 != chain);
1677
1678         if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
1679                 chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
1680                 return false;
1681         }
1682
1683         if (0 != chain->filename) {
1684                 chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
1685                 return false;
1686         }
1687
1688         if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
1689                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1690                 return false;
1691         }
1692         if (0 == temp_callbacks.write) {
1693                 chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
1694                 return false;
1695         }
1696
1697         if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
1698                 chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
1699                 return false;
1700         }
1701
1702         current_length = chain_prepare_for_write_(chain, use_padding);
1703
1704         /* a return value of 0 means there was an error; chain->status is already set */
1705         if (0 == current_length)
1706                 return false;
1707
1708         FLAC__ASSERT(current_length != chain->initial_length);
1709
1710         /* rewind */
1711         if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
1712                 chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
1713                 return false;
1714         }
1715
1716         if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
1717                 return false;
1718
1719         /* recompute lengths and offsets */
1720         {
1721                 const FLAC__Metadata_Node *node;
1722                 chain->initial_length = current_length;
1723                 chain->last_offset = chain->first_offset;
1724                 for(node = chain->head; node; node = node->next)
1725                         chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
1726         }
1727
1728         return true;
1729 }
1730
1731 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
1732 {
1733         FLAC__Metadata_Node *node;
1734
1735         FLAC__ASSERT(0 != chain);
1736
1737         for(node = chain->head; node; ) {
1738                 if(!chain_merge_adjacent_padding_(chain, node))
1739                         node = node->next;
1740         }
1741 }
1742
1743 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
1744 {
1745         FLAC__Metadata_Node *node, *save;
1746         unsigned i;
1747
1748         FLAC__ASSERT(0 != chain);
1749
1750         /*
1751          * Don't try and be too smart... this simple algo is good enough for
1752          * the small number of nodes that we deal with.
1753          */
1754         for(i = 0, node = chain->head; i < chain->nodes; i++) {
1755                 if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
1756                         save = node->next;
1757                         chain_remove_node_(chain, node);
1758                         chain_append_node_(chain, node);
1759                         node = save;
1760                 }
1761                 else {
1762                         node = node->next;
1763                 }
1764         }
1765
1766         FLAC__metadata_chain_merge_padding(chain);
1767 }
1768
1769
1770 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new()
1771 {
1772         FLAC__Metadata_Iterator *iterator = (FLAC__Metadata_Iterator*)calloc(1, sizeof(FLAC__Metadata_Iterator));
1773
1774         /* calloc() implies:
1775                 iterator->current = 0;
1776                 iterator->chain = 0;
1777         */
1778
1779         return iterator;
1780 }
1781
1782 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
1783 {
1784         FLAC__ASSERT(0 != iterator);
1785
1786         free(iterator);
1787 }
1788
1789 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
1790 {
1791         FLAC__ASSERT(0 != iterator);
1792         FLAC__ASSERT(0 != chain);
1793         FLAC__ASSERT(0 != chain->head);
1794
1795         iterator->chain = chain;
1796         iterator->current = chain->head;
1797 }
1798
1799 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
1800 {
1801         FLAC__ASSERT(0 != iterator);
1802
1803         if(0 == iterator->current || 0 == iterator->current->next)
1804                 return false;
1805
1806         iterator->current = iterator->current->next;
1807         return true;
1808 }
1809
1810 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
1811 {
1812         FLAC__ASSERT(0 != iterator);
1813
1814         if(0 == iterator->current || 0 == iterator->current->prev)
1815                 return false;
1816
1817         iterator->current = iterator->current->prev;
1818         return true;
1819 }
1820
1821 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
1822 {
1823         FLAC__ASSERT(0 != iterator);
1824         FLAC__ASSERT(0 != iterator->current);
1825         FLAC__ASSERT(0 != iterator->current->data);
1826
1827         return iterator->current->data->type;
1828 }
1829
1830 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
1831 {
1832         FLAC__ASSERT(0 != iterator);
1833         FLAC__ASSERT(0 != iterator->current);
1834
1835         return iterator->current->data;
1836 }
1837
1838 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1839 {
1840         FLAC__ASSERT(0 != iterator);
1841         FLAC__ASSERT(0 != block);
1842         return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
1843 }
1844
1845 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
1846 {
1847         FLAC__Metadata_Node *save;
1848
1849         FLAC__ASSERT(0 != iterator);
1850         FLAC__ASSERT(0 != iterator->current);
1851
1852         if(0 == iterator->current->prev) {
1853                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1854                 return false;
1855         }
1856
1857         save = iterator->current->prev;
1858
1859         if(replace_with_padding) {
1860                 FLAC__metadata_object_delete_data(iterator->current->data);
1861                 iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
1862         }
1863         else {
1864                 chain_delete_node_(iterator->chain, iterator->current);
1865         }
1866
1867         iterator->current = save;
1868         return true;
1869 }
1870
1871 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1872 {
1873         FLAC__Metadata_Node *node;
1874
1875         FLAC__ASSERT(0 != iterator);
1876         FLAC__ASSERT(0 != iterator->current);
1877         FLAC__ASSERT(0 != block);
1878
1879         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1880                 return false;
1881
1882         if(0 == iterator->current->prev) {
1883                 FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
1884                 return false;
1885         }
1886
1887         if(0 == (node = node_new_()))
1888                 return false;
1889
1890         node->data = block;
1891         iterator_insert_node_(iterator, node);
1892         iterator->current = node;
1893         return true;
1894 }
1895
1896 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
1897 {
1898         FLAC__Metadata_Node *node;
1899
1900         FLAC__ASSERT(0 != iterator);
1901         FLAC__ASSERT(0 != iterator->current);
1902         FLAC__ASSERT(0 != block);
1903
1904         if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
1905                 return false;
1906
1907         if(0 == (node = node_new_()))
1908                 return false;
1909
1910         node->data = block;
1911         iterator_insert_node_after_(iterator, node);
1912         iterator->current = node;
1913         return true;
1914 }
1915
1916
1917 /****************************************************************************
1918  *
1919  * Local function definitions
1920  *
1921  ***************************************************************************/
1922
1923 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1924 {
1925         unsigned i;
1926
1927         b += bytes;
1928
1929         for(i = 0; i < bytes; i++) {
1930                 *(--b) = (FLAC__byte)(val & 0xff);
1931                 val >>= 8;
1932         }
1933 }
1934
1935 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
1936 {
1937         unsigned i;
1938
1939         for(i = 0; i < bytes; i++) {
1940                 *(b++) = (FLAC__byte)(val & 0xff);
1941                 val >>= 8;
1942         }
1943 }
1944
1945 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
1946 {
1947         unsigned i;
1948
1949         b += bytes;
1950
1951         for(i = 0; i < bytes; i++) {
1952                 *(--b) = (FLAC__byte)(val & 0xff);
1953                 val >>= 8;
1954         }
1955 }
1956
1957 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
1958 {
1959         FLAC__uint32 ret = 0;
1960         unsigned i;
1961
1962         for(i = 0; i < bytes; i++)
1963                 ret = (ret << 8) | (FLAC__uint32)(*b++);
1964
1965         return ret;
1966 }
1967
1968 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
1969 {
1970         FLAC__uint32 ret = 0;
1971         unsigned i;
1972
1973         b += bytes;
1974
1975         for(i = 0; i < bytes; i++)
1976                 ret = (ret << 8) | (FLAC__uint32)(*--b);
1977
1978         return ret;
1979 }
1980
1981 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
1982 {
1983         FLAC__uint64 ret = 0;
1984         unsigned i;
1985
1986         for(i = 0; i < bytes; i++)
1987                 ret = (ret << 8) | (FLAC__uint64)(*b++);
1988
1989         return ret;
1990 }
1991
1992 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
1993 {
1994         FLAC__ASSERT(0 != iterator);
1995         FLAC__ASSERT(0 != iterator->file);
1996
1997         if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
1998                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
1999                 return false;
2000         }
2001
2002         return true;
2003 }
2004
2005 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
2006 {
2007         FLAC__ASSERT(0 != iterator);
2008         FLAC__ASSERT(0 != iterator->file);
2009
2010         iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
2011
2012         return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
2013 }
2014
2015 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
2016 {
2017         FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
2018
2019         if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2020                 return false;
2021
2022         *is_last = raw_header[0] & 0x80? true : false;
2023         *type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
2024         *length = unpack_uint32_(raw_header + 1, 3);
2025
2026         /* Note that we don't check:
2027          *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
2028          * we just will read in an opaque block
2029          */
2030
2031         return true;
2032 }
2033
2034 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
2035 {
2036         switch(block->type) {
2037                 case FLAC__METADATA_TYPE_STREAMINFO:
2038                         return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
2039                 case FLAC__METADATA_TYPE_PADDING:
2040                         return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
2041                 case FLAC__METADATA_TYPE_APPLICATION:
2042                         return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
2043                 case FLAC__METADATA_TYPE_SEEKTABLE:
2044                         return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
2045                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2046                         return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, &block->data.vorbis_comment);
2047                 case FLAC__METADATA_TYPE_CUESHEET:
2048                         return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
2049                 case FLAC__METADATA_TYPE_PICTURE:
2050                         return read_metadata_block_data_picture_cb_(handle, read_cb, &block->data.picture);
2051                 default:
2052                         return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
2053         }
2054 }
2055
2056 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
2057 {
2058         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
2059
2060         if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2061                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2062
2063         b = buffer;
2064
2065         /* we are using hardcoded numbers for simplicity but we should
2066          * probably eventually write a bit-level unpacker and use the
2067          * _STREAMINFO_ constants.
2068          */
2069         block->min_blocksize = unpack_uint32_(b, 2); b += 2;
2070         block->max_blocksize = unpack_uint32_(b, 2); b += 2;
2071         block->min_framesize = unpack_uint32_(b, 3); b += 3;
2072         block->max_framesize = unpack_uint32_(b, 3); b += 3;
2073         block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
2074         block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
2075         block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
2076         block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
2077         memcpy(block->md5sum, b+8, 16);
2078
2079         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2080 }
2081
2082 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
2083 {
2084         (void)block; /* nothing to do; we don't care about reading the padding bytes */
2085
2086         if(0 != seek_cb(handle, block_length, SEEK_CUR))
2087                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2088
2089         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2090 }
2091
2092 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
2093 {
2094         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2095
2096         if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
2097                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2098
2099         block_length -= id_bytes;
2100
2101         if(block_length == 0) {
2102                 block->data = 0;
2103         }
2104         else {
2105                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2106                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2107
2108                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2109                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2110         }
2111
2112         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2113 }
2114
2115 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
2116 {
2117         unsigned i;
2118         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2119
2120         FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
2121
2122         block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
2123
2124         if(block->num_points == 0)
2125                 block->points = 0;
2126         else if(0 == (block->points = (FLAC__StreamMetadata_SeekPoint*)malloc(block->num_points * sizeof(FLAC__StreamMetadata_SeekPoint))))
2127                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2128
2129         for(i = 0; i < block->num_points; i++) {
2130                 if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2131                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2132                 /* some MAGIC NUMBERs here */
2133                 block->points[i].sample_number = unpack_uint64_(buffer, 8);
2134                 block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
2135                 block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
2136         }
2137
2138         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2139 }
2140
2141 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry)
2142 {
2143         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2144         FLAC__byte buffer[4]; /* magic number is asserted below */
2145
2146         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == sizeof(buffer));
2147
2148         if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2149                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2150         entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
2151
2152         if(0 != entry->entry)
2153                 free(entry->entry);
2154
2155         if(entry->length == 0) {
2156                 entry->entry = 0;
2157         }
2158         else {
2159                 if(0 == (entry->entry = (FLAC__byte*)malloc(entry->length+1)))
2160                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2161
2162                 if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
2163                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2164
2165                 entry->entry[entry->length] = '\0';
2166         }
2167
2168         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2169 }
2170
2171 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment *block)
2172 {
2173         unsigned i;
2174         FLAC__Metadata_SimpleIteratorStatus status;
2175         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2176         FLAC__byte buffer[4]; /* magic number is asserted below */
2177
2178         FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == sizeof(buffer));
2179
2180         if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string))))
2181                 return status;
2182
2183         if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2184                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2185         block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
2186
2187         if(block->num_comments == 0) {
2188                 block->comments = 0;
2189         }
2190         else if(0 == (block->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry))))
2191                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2192
2193         for(i = 0; i < block->num_comments; i++) {
2194                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i)))
2195                         return status;
2196         }
2197
2198         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2199 }
2200
2201 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
2202 {
2203         unsigned i, len;
2204         FLAC__byte buffer[32]; /* asserted below that this is big enough */
2205
2206         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2207         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2208         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);
2209
2210         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2211         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2212         if(read_cb(buffer, 1, len, handle) != len)
2213                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2214         track->offset = unpack_uint64_(buffer, len);
2215
2216         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2217         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2218         if(read_cb(buffer, 1, len, handle) != len)
2219                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2220         track->number = (FLAC__byte)unpack_uint32_(buffer, len);
2221
2222         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2223         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2224         if(read_cb(track->isrc, 1, len, handle) != len)
2225                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2226
2227         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);
2228         len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2229         if(read_cb(buffer, 1, len, handle) != len)
2230                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2231         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
2232         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
2233         track->type = buffer[0] >> 7;
2234         track->pre_emphasis = (buffer[0] >> 6) & 1;
2235
2236         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2237         len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2238         if(read_cb(buffer, 1, len, handle) != len)
2239                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2240         track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
2241
2242         if(track->num_indices == 0) {
2243                 track->indices = 0;
2244         }
2245         else if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
2246                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2247
2248         for(i = 0; i < track->num_indices; i++) {
2249                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2250                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2251                 if(read_cb(buffer, 1, len, handle) != len)
2252                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2253                 track->indices[i].offset = unpack_uint64_(buffer, len);
2254
2255                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2256                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2257                 if(read_cb(buffer, 1, len, handle) != len)
2258                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2259                 track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
2260
2261                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2262                 len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2263                 if(read_cb(buffer, 1, len, handle) != len)
2264                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2265         }
2266
2267         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2268 }
2269
2270 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
2271 {
2272         unsigned i, len;
2273         FLAC__Metadata_SimpleIteratorStatus status;
2274         FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
2275
2276         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
2277         FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
2278
2279         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2280         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2281         if(read_cb(block->media_catalog_number, 1, len, handle) != len)
2282                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2283
2284         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2285         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2286         if(read_cb(buffer, 1, len, handle) != len)
2287                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2288         block->lead_in = unpack_uint64_(buffer, len);
2289
2290         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2291         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2292         if(read_cb(buffer, 1, len, handle) != len)
2293                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2294         block->is_cd = buffer[0]&0x80? true : false;
2295
2296         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2297         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2298         if(read_cb(buffer, 1, len, handle) != len)
2299                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2300         block->num_tracks = unpack_uint32_(buffer, len);
2301
2302         if(block->num_tracks == 0) {
2303                 block->tracks = 0;
2304         }
2305         else if(0 == (block->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
2306                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2307
2308         for(i = 0; i < block->num_tracks; i++) {
2309                 if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
2310                         return status;
2311         }
2312
2313         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2314 }
2315
2316 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)
2317 {
2318         FLAC__byte buffer[sizeof(FLAC__uint32)];
2319
2320         FLAC__ASSERT(0 != data);
2321         FLAC__ASSERT(length_len%8 == 0);
2322
2323         length_len /= 8; /* convert to bytes */
2324
2325         FLAC__ASSERT(sizeof(buffer) >= length_len);
2326
2327         if(read_cb(buffer, 1, length_len, handle) != length_len)
2328                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2329         *length = unpack_uint32_(buffer, length_len);
2330
2331         if(0 != *data)
2332                 free(*data);
2333
2334         if(0 == (*data = (FLAC__byte*)malloc(*length+1)))
2335                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2336
2337         if(*length > 0) {
2338                 if(read_cb(*data, 1, *length, handle) != *length)
2339                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2340         }
2341
2342         (*data)[*length] = '\0';
2343
2344         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2345 }
2346
2347 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block)
2348 {
2349         FLAC__Metadata_SimpleIteratorStatus status;
2350         FLAC__byte buffer[4]; /* asserted below that this is big enough */
2351         FLAC__uint32 len;
2352
2353         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2354         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2355         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2356         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2357         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
2358
2359         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_TYPE_LEN % 8 == 0);
2360         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN / 8;
2361         if(read_cb(buffer, 1, len, handle) != len)
2362                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2363         block->type = (FLAC__StreamMetadata_Picture_Type)unpack_uint32_(buffer, len);
2364
2365         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)
2366                 return status;
2367
2368         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)
2369                 return status;
2370
2371         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN % 8 == 0);
2372         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN / 8;
2373         if(read_cb(buffer, 1, len, handle) != len)
2374                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2375         block->width = unpack_uint32_(buffer, len);
2376
2377         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN % 8 == 0);
2378         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN / 8;
2379         if(read_cb(buffer, 1, len, handle) != len)
2380                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2381         block->height = unpack_uint32_(buffer, len);
2382
2383         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN % 8 == 0);
2384         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN / 8;
2385         if(read_cb(buffer, 1, len, handle) != len)
2386                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2387         block->depth = unpack_uint32_(buffer, len);
2388
2389         FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_COLORS_LEN % 8 == 0);
2390         len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN / 8;
2391         if(read_cb(buffer, 1, len, handle) != len)
2392                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2393         block->colors = unpack_uint32_(buffer, len);
2394
2395         /* for convenience we use read_metadata_block_data_picture_cstring_cb_() even though it adds an extra terminating NUL we don't use */
2396         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)
2397                 return status;
2398
2399         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2400 }
2401
2402 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2403 {
2404         if(block_length == 0) {
2405                 block->data = 0;
2406         }
2407         else {
2408                 if(0 == (block->data = (FLAC__byte*)malloc(block_length)))
2409                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2410
2411                 if(read_cb(block->data, 1, block_length, handle) != block_length)
2412                         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
2413         }
2414
2415         return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2416 }
2417
2418 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2419 {
2420         FLAC__ASSERT(0 != file);
2421         FLAC__ASSERT(0 != status);
2422
2423         if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2424                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2425                 return false;
2426         }
2427
2428         return true;
2429 }
2430
2431 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
2432 {
2433         FLAC__ASSERT(0 != file);
2434         FLAC__ASSERT(0 != status);
2435
2436         if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
2437                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
2438                 return true;
2439         }
2440         else {
2441                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
2442                 return false;
2443         }
2444 }
2445
2446 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2447 {
2448         FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
2449
2450         FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
2451
2452         buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
2453         pack_uint32_(block->length, buffer + 1, 3);
2454
2455         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
2456                 return false;
2457
2458         return true;
2459 }
2460
2461 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
2462 {
2463         FLAC__ASSERT(0 != block);
2464
2465         switch(block->type) {
2466                 case FLAC__METADATA_TYPE_STREAMINFO:
2467                         return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
2468                 case FLAC__METADATA_TYPE_PADDING:
2469                         return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
2470                 case FLAC__METADATA_TYPE_APPLICATION:
2471                         return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
2472                 case FLAC__METADATA_TYPE_SEEKTABLE:
2473                         return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
2474                 case FLAC__METADATA_TYPE_VORBIS_COMMENT:
2475                         return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
2476                 case FLAC__METADATA_TYPE_CUESHEET:
2477                         return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
2478                 case FLAC__METADATA_TYPE_PICTURE:
2479                         return write_metadata_block_data_picture_cb_(handle, write_cb, &block->data.picture);
2480                 default:
2481                         return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
2482         }
2483 }
2484
2485 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
2486 {
2487         FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
2488         const unsigned channels1 = block->channels - 1;
2489         const unsigned bps1 = block->bits_per_sample - 1;
2490
2491         /* we are using hardcoded numbers for simplicity but we should
2492          * probably eventually write a bit-level packer and use the
2493          * _STREAMINFO_ constants.
2494          */
2495         pack_uint32_(block->min_blocksize, buffer, 2);
2496         pack_uint32_(block->max_blocksize, buffer+2, 2);
2497         pack_uint32_(block->min_framesize, buffer+4, 3);
2498         pack_uint32_(block->max_framesize, buffer+7, 3);
2499         buffer[10] = (block->sample_rate >> 12) & 0xff;
2500         buffer[11] = (block->sample_rate >> 4) & 0xff;
2501         buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
2502         buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
2503         pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
2504         memcpy(buffer+18, block->md5sum, 16);
2505
2506         if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
2507                 return false;
2508
2509         return true;
2510 }
2511
2512 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
2513 {
2514         unsigned i, n = block_length;
2515         FLAC__byte buffer[1024];
2516
2517         (void)block;
2518
2519         memset(buffer, 0, 1024);
2520
2521         for(i = 0; i < n/1024; i++)
2522                 if(write_cb(buffer, 1, 1024, handle) != 1024)
2523                         return false;
2524
2525         n %= 1024;
2526
2527         if(write_cb(buffer, 1, n, handle) != n)
2528                 return false;
2529
2530         return true;
2531 }
2532
2533 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
2534 {
2535         const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
2536
2537         if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
2538                 return false;
2539
2540         block_length -= id_bytes;
2541
2542         if(write_cb(block->data, 1, block_length, handle) != block_length)
2543                 return false;
2544
2545         return true;
2546 }
2547
2548 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
2549 {
2550         unsigned i;
2551         FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
2552
2553         for(i = 0; i < block->num_points; i++) {
2554                 /* some MAGIC NUMBERs here */
2555                 pack_uint64_(block->points[i].sample_number, buffer, 8);
2556                 pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
2557                 pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
2558                 if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
2559                         return false;
2560         }
2561
2562         return true;
2563 }
2564
2565 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
2566 {
2567         unsigned i;
2568         const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
2569         const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
2570         FLAC__byte buffer[4]; /* magic number is asserted below */
2571
2572         FLAC__ASSERT(max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == sizeof(buffer));
2573
2574         pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
2575         if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2576                 return false;
2577         if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
2578                 return false;
2579
2580         pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
2581         if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
2582                 return false;
2583
2584         for(i = 0; i < block->num_comments; i++) {
2585                 pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
2586                 if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
2587                         return false;
2588                 if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
2589                         return false;
2590         }
2591
2592         return true;
2593 }
2594
2595 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
2596 {
2597         unsigned i, j, len;
2598         FLAC__byte buffer[1024]; /* asserted below that this is big enough */
2599
2600         FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
2601         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
2602         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);
2603         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
2604
2605         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
2606         len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
2607         if(write_cb(block->media_catalog_number, 1, len, handle) != len)
2608                 return false;
2609
2610         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
2611         len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
2612         pack_uint64_(block->lead_in, buffer, len);
2613         if(write_cb(buffer, 1, len, handle) != len)
2614                 return false;
2615
2616         FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
2617         len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
2618         memset(buffer, 0, len);
2619         if(block->is_cd)
2620                 buffer[0] |= 0x80;
2621         if(write_cb(buffer, 1, len, handle) != len)
2622                 return false;
2623
2624         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
2625         len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
2626         pack_uint32_(block->num_tracks, buffer, len);
2627         if(write_cb(buffer, 1, len, handle) != len)
2628                 return false;
2629
2630         for(i = 0; i < block->num_tracks; i++) {
2631                 FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
2632
2633                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
2634                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
2635                 pack_uint64_(track->offset, buffer, len);
2636                 if(write_cb(buffer, 1, len, handle) != len)
2637                         return false;
2638
2639                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
2640                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
2641                 pack_uint32_(track->number, buffer, len);
2642                 if(write_cb(buffer, 1, len, handle) != len)
2643                         return false;
2644
2645                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
2646                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
2647                 if(write_cb(track->isrc, 1, len, handle) != len)
2648                         return false;
2649
2650                 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);
2651                 len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
2652                 memset(buffer, 0, len);
2653                 buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
2654                 if(write_cb(buffer, 1, len, handle) != len)
2655                         return false;
2656
2657                 FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
2658                 len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
2659                 pack_uint32_(track->num_indices, buffer, len);
2660                 if(write_cb(buffer, 1, len, handle) != len)
2661                         return false;
2662
2663                 for(j = 0; j < track->num_indices; j++) {
2664                         FLAC__StreamMetadata_CueSheet_Index *index = track->indices + j;
2665
2666                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
2667                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
2668                         pack_uint64_(index->offset, buffer, len);
2669                         if(write_cb(buffer, 1, len, handle) != len)
2670                                 return false;
2671
2672                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
2673                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
2674                         pack_uint32_(index->number, buffer, len);
2675                         if(write_cb(buffer, 1, len, handle) != len)
2676                                 return false;
2677
2678                         FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
2679                         len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
2680                         memset(buffer, 0, len);
2681                         if(write_cb(buffer, 1, len, handle) != len)
2682                                 return false;
2683                 }
2684         }
2685
2686         return true;
2687 }
2688
2689 FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block)
2690 {
2691         unsigned len;
2692         size_t slen;
2693         FLAC__byte buffer[4]; /* magic number is asserted below */
2694
2695         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_TYPE_LEN%8);
2696         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN%8);
2697         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN%8);
2698         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN%8);
2699         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN%8);
2700         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN%8);
2701         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_COLORS_LEN%8);
2702         FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN%8);
2703         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
2704         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8);
2705         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8);
2706         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
2707         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
2708         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
2709         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
2710         FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8);
2711
2712         len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8;
2713         pack_uint32_(block->type, buffer, len);
2714         if(write_cb(buffer, 1, len, handle) != len)
2715                 return false;
2716
2717         len = FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8;
2718         slen = strlen(block->mime_type);
2719         pack_uint32_(slen, buffer, len);
2720         if(write_cb(buffer, 1, len, handle) != len)
2721                 return false;
2722         if(write_cb(block->mime_type, 1, slen, handle) != slen)
2723                 return false;
2724
2725         len = FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8;
2726         slen = strlen((const char *)block->description);
2727         pack_uint32_(slen, buffer, len);
2728         if(write_cb(buffer, 1, len, handle) != len)
2729                 return false;
2730         if(write_cb(block->description, 1, slen, handle) != slen)
2731                 return false;
2732
2733         len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8;
2734         pack_uint32_(block->width, buffer, len);
2735         if(write_cb(buffer, 1, len, handle) != len)
2736                 return false;
2737
2738         len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8;
2739         pack_uint32_(block->height, buffer, len);
2740         if(write_cb(buffer, 1, len, handle) != len)
2741                 return false;
2742
2743         len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8;
2744         pack_uint32_(block->depth, buffer, len);
2745         if(write_cb(buffer, 1, len, handle) != len)
2746                 return false;
2747
2748         len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8;
2749         pack_uint32_(block->colors, buffer, len);
2750         if(write_cb(buffer, 1, len, handle) != len)
2751                 return false;
2752
2753         len = FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8;
2754         pack_uint32_(block->data_length, buffer, len);
2755         if(write_cb(buffer, 1, len, handle) != len)
2756                 return false;
2757         if(write_cb(block->data, 1, block->data_length, handle) != block->data_length)
2758                 return false;
2759
2760         return true;
2761 }
2762
2763 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
2764 {
2765         if(write_cb(block->data, 1, block_length, handle) != block_length)
2766                 return false;
2767
2768         return true;
2769 }
2770
2771 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
2772 {
2773         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2774                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2775                 return false;
2776         }
2777
2778         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2779                 return false;
2780
2781         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2782                 return false;
2783
2784         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2785                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2786                 return false;
2787         }
2788
2789         return read_metadata_block_header_(iterator);
2790 }
2791
2792 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
2793 {
2794         FLAC__StreamMetadata *padding;
2795
2796         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2797                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2798                 return false;
2799         }
2800
2801         block->is_last = false;
2802
2803         if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
2804                 return false;
2805
2806         if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
2807                 return false;
2808
2809         if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
2810                 return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
2811
2812         padding->is_last = padding_is_last;
2813         padding->length = padding_length;
2814
2815         if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
2816                 FLAC__metadata_object_delete(padding);
2817                 return false;
2818         }
2819
2820         if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
2821                 FLAC__metadata_object_delete(padding);
2822                 return false;
2823         }
2824
2825         FLAC__metadata_object_delete(padding);
2826
2827         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2828                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2829                 return false;
2830         }
2831
2832         return read_metadata_block_header_(iterator);
2833 }
2834
2835 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
2836 {
2837         FILE *tempfile;
2838         char *tempfilename;
2839         int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
2840         off_t fixup_is_last_flag_offset = -1;
2841
2842         FLAC__ASSERT(0 != block || append == false);
2843
2844         if(iterator->is_last) {
2845                 if(append) {
2846                         fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
2847                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2848                 }
2849                 else if(0 == block) {
2850                         simple_iterator_push_(iterator);
2851                         if(!FLAC__metadata_simple_iterator_prev(iterator)) {
2852                                 (void)simple_iterator_pop_(iterator);
2853                                 return false;
2854                         }
2855                         fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
2856                         fixup_is_last_flag_offset = iterator->offset[iterator->depth];
2857                         if(!simple_iterator_pop_(iterator))
2858                                 return false;
2859                 }
2860         }
2861
2862         if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
2863                 return false;
2864
2865         if(0 != block) {
2866                 if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
2867                         cleanup_tempfile_(&tempfile, &tempfilename);
2868                         return false;
2869                 }
2870
2871                 if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
2872                         cleanup_tempfile_(&tempfile, &tempfilename);
2873                         return false;
2874                 }
2875         }
2876
2877         if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
2878                 return false;
2879
2880         if(append)
2881                 return FLAC__metadata_simple_iterator_next(iterator);
2882
2883         return true;
2884 }
2885
2886 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
2887 {
2888         FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
2889         iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
2890         iterator->depth++;
2891 }
2892
2893 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
2894 {
2895         FLAC__ASSERT(iterator->depth > 0);
2896         iterator->depth--;
2897         if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
2898                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2899                 return false;
2900         }
2901
2902         return read_metadata_block_header_(iterator);
2903 }
2904
2905 /* return meanings:
2906  * 0: ok
2907  * 1: read error
2908  * 2: seek error
2909  * 3: not a FLAC file
2910  */
2911 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
2912 {
2913         FLAC__byte buffer[4];
2914         size_t n;
2915         unsigned i;
2916
2917         FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == sizeof(buffer));
2918
2919         /* skip any id3v2 tag */
2920         errno = 0;
2921         n = read_cb(buffer, 1, 4, handle);
2922         if(errno)
2923                 return 1;
2924         else if(n != 4)
2925                 return 3;
2926         else if(0 == memcmp(buffer, "ID3", 3)) {
2927                 unsigned tag_length = 0;
2928
2929                 /* skip to the tag length */
2930                 if(seek_cb(handle, 2, SEEK_CUR) < 0)
2931                         return 2;
2932
2933                 /* read the length */
2934                 for(i = 0; i < 4; i++) {
2935                         if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
2936                                 return 1;
2937                         tag_length <<= 7;
2938                         tag_length |= (buffer[0] & 0x7f);
2939                 }
2940
2941                 /* skip the rest of the tag */
2942                 if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
2943                         return 2;
2944
2945                 /* read the stream sync code */
2946                 errno = 0;
2947                 n = read_cb(buffer, 1, 4, handle);
2948                 if(errno)
2949                         return 1;
2950                 else if(n != 4)
2951                         return 3;
2952         }
2953
2954         /* check for the fLaC signature */
2955         if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
2956                 return 0;
2957         else
2958                 return 3;
2959 }
2960
2961 unsigned seek_to_first_metadata_block_(FILE *f)
2962 {
2963         return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
2964 }
2965
2966 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
2967 {
2968         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];
2969
2970         if(0 != fseeko(iterator->file, 0, SEEK_SET)) {
2971                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2972                 return false;
2973         }
2974         if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
2975                 cleanup_tempfile_(tempfile, tempfilename);
2976                 return false;
2977         }
2978         if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
2979                 cleanup_tempfile_(tempfile, tempfilename);
2980                 return false;
2981         }
2982
2983         return true;
2984 }
2985
2986 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)
2987 {
2988         off_t save_offset = iterator->offset[iterator->depth];
2989         FLAC__ASSERT(0 != *tempfile);
2990
2991         if(0 != fseeko(iterator->file, save_offset + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length, SEEK_SET)) {
2992                 cleanup_tempfile_(tempfile, tempfilename);
2993                 iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
2994                 return false;
2995         }
2996         if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
2997                 cleanup_tempfile_(tempfile, tempfilename);
2998                 return false;
2999         }
3000
3001         if(fixup_is_last_code != 0) {
3002                 /*
3003                  * if code == 1, it means a block was appended to the end so
3004                  *   we have to clear the is_last flag of the previous block
3005                  * if code == -1, it means the last block was deleted so
3006                  *   we have to set the is_last flag of the previous block
3007                  */
3008                 /* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
3009                 FLAC__byte x;
3010                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
3011                         cleanup_tempfile_(tempfile, tempfilename);
3012                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
3013                         return false;
3014                 }
3015                 if(fread(&x, 1, 1, *tempfile) != 1) {
3016                         cleanup_tempfile_(tempfile, tempfilename);
3017                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
3018                         return false;
3019                 }
3020                 if(fixup_is_last_code > 0) {
3021                         FLAC__ASSERT(x & 0x80);
3022                         x &= 0x7f;
3023                 }
3024                 else {
3025                         FLAC__ASSERT(!(x & 0x80));
3026                         x |= 0x80;
3027                 }
3028                 if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
3029                         cleanup_tempfile_(tempfile, tempfilename);
3030                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
3031                         return false;
3032                 }
3033                 if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
3034                         cleanup_tempfile_(tempfile, tempfilename);
3035                         iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
3036                         return false;
3037                 }
3038         }
3039
3040         (void)fclose(iterator->file);
3041
3042         if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
3043                 return false;
3044
3045         if(iterator->has_stats)
3046                 set_file_stats_(iterator->filename, &iterator->stats);
3047
3048         if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
3049                 return false;
3050         if(backup) {
3051                 while(iterator->offset[iterator->depth] + (off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (off_t)iterator->length < save_offset)
3052                         if(!FLAC__metadata_simple_iterator_next(iterator))
3053                                 return false;
3054                 return true;
3055         }
3056         else {
3057                 /* move the iterator to it's original block faster by faking a push, then doing a pop_ */
3058                 FLAC__ASSERT(iterator->depth == 0);
3059                 iterator->offset[0] = save_offset;
3060                 iterator->depth++;
3061                 return simple_iterator_pop_(iterator);
3062         }
3063 }
3064
3065 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
3066 {
3067         FLAC__byte buffer[8192];
3068         size_t n;
3069
3070         FLAC__ASSERT(bytes >= 0);
3071         while(bytes > 0) {
3072                 n = min(sizeof(buffer), (size_t)bytes);
3073                 if(fread(buffer, 1, n, file) != n) {
3074                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
3075                         return false;
3076                 }
3077                 if(local__fwrite(buffer, 1, n, tempfile) != n) {
3078                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
3079                         return false;
3080                 }
3081                 bytes -= n;
3082         }
3083
3084         return true;
3085 }
3086
3087 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)
3088 {
3089         FLAC__byte buffer[8192];
3090         size_t n;
3091
3092         FLAC__ASSERT(bytes >= 0);
3093         while(bytes > 0) {
3094                 n = min(sizeof(buffer), (size_t)bytes);
3095                 if(read_cb(buffer, 1, n, handle) != n) {
3096                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
3097                         return false;
3098                 }
3099                 if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
3100                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
3101                         return false;
3102                 }
3103                 bytes -= n;
3104         }
3105
3106         return true;
3107 }
3108
3109 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
3110 {
3111         FLAC__byte buffer[8192];
3112         size_t n;
3113
3114         while(!feof(file)) {
3115                 n = fread(buffer, 1, sizeof(buffer), file);
3116                 if(n == 0 && !feof(file)) {
3117                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
3118                         return false;
3119                 }
3120                 if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
3121                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
3122                         return false;
3123                 }
3124         }
3125
3126         return true;
3127 }
3128
3129 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)
3130 {
3131         FLAC__byte buffer[8192];
3132         size_t n;
3133
3134         while(!eof_cb(handle)) {
3135                 n = read_cb(buffer, 1, sizeof(buffer), handle);
3136                 if(n == 0 && !eof_cb(handle)) {
3137                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
3138                         return false;
3139                 }
3140                 if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
3141                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
3142                         return false;
3143                 }
3144         }
3145
3146         return true;
3147 }
3148
3149 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
3150 {
3151         static const char *tempfile_suffix = ".metadata_edit";
3152         if(0 == tempfile_path_prefix) {
3153                 if(0 == (*tempfilename = (char*)malloc(strlen(filename) + strlen(tempfile_suffix) + 1))) {
3154                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
3155                         return false;
3156                 }
3157                 strcpy(*tempfilename, filename);
3158                 strcat(*tempfilename, tempfile_suffix);
3159         }
3160         else {
3161                 const char *p = strrchr(filename, '/');
3162                 if(0 == p)
3163                         p = filename;
3164                 else
3165                         p++;
3166
3167                 if(0 == (*tempfilename = (char*)malloc(strlen(tempfile_path_prefix) + 1 + strlen(p) + strlen(tempfile_suffix) + 1))) {
3168                         *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
3169                         return false;
3170                 }
3171                 strcpy(*tempfilename, tempfile_path_prefix);
3172                 strcat(*tempfilename, "/");
3173                 strcat(*tempfilename, p);
3174                 strcat(*tempfilename, tempfile_suffix);
3175         }
3176
3177         if(0 == (*tempfile = fopen(*tempfilename, "w+b"))) {
3178                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
3179                 return false;
3180         }
3181
3182         return true;
3183 }
3184
3185 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
3186 {
3187         FLAC__ASSERT(0 != filename);
3188         FLAC__ASSERT(0 != tempfile);
3189         FLAC__ASSERT(0 != *tempfile);
3190         FLAC__ASSERT(0 != tempfilename);
3191         FLAC__ASSERT(0 != *tempfilename);
3192         FLAC__ASSERT(0 != status);
3193
3194         (void)fclose(*tempfile);
3195         *tempfile = 0;
3196
3197 #if defined _MSC_VER || defined __MINGW32__ || defined __EMX__
3198         /* on some flavors of windows, rename() will fail if the destination already exists */
3199         if(unlink(filename) < 0) {
3200                 cleanup_tempfile_(tempfile, tempfilename);
3201                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
3202                 return false;
3203         }
3204 #endif
3205
3206         /*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just rename(): */
3207         if(0 != rename(*tempfilename, filename)) {
3208                 cleanup_tempfile_(tempfile, tempfilename);
3209                 *status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
3210                 return false;
3211         }
3212
3213         cleanup_tempfile_(tempfile, tempfilename);
3214
3215         return true;
3216 }
3217
3218 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
3219 {
3220         if(0 != *tempfile) {
3221                 (void)fclose(*tempfile);
3222                 *tempfile = 0;
3223         }
3224
3225         if(0 != *tempfilename) {
3226                 (void)unlink(*tempfilename);
3227                 free(*tempfilename);
3228                 *tempfilename = 0;
3229         }
3230 }
3231
3232 FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
3233 {
3234         FLAC__ASSERT(0 != filename);
3235         FLAC__ASSERT(0 != stats);
3236         return (0 == stat(filename, stats));
3237 }
3238
3239 void set_file_stats_(const char *filename, struct stat *stats)
3240 {
3241         struct utimbuf srctime;
3242
3243         FLAC__ASSERT(0 != filename);
3244         FLAC__ASSERT(0 != stats);
3245
3246         srctime.actime = stats->st_atime;
3247         srctime.modtime = stats->st_mtime;
3248         (void)chmod(filename, stats->st_mode);
3249         (void)utime(filename, &srctime);
3250 #if !defined _MSC_VER && !defined __MINGW32__ && !defined __EMX__
3251         (void)chown(filename, stats->st_uid, -1);
3252         (void)chown(filename, -1, stats->st_gid);
3253 #endif
3254 }
3255
3256 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
3257 {
3258         return fseeko((FILE*)handle, (off_t)offset, whence);
3259 }
3260
3261 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
3262 {
3263         return ftello((FILE*)handle);
3264 }
3265
3266 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
3267 {
3268         switch(status) {
3269                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
3270                         return FLAC__METADATA_CHAIN_STATUS_OK;
3271                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
3272                         return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
3273                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
3274                         return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
3275                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
3276                         return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
3277                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
3278                         return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
3279                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
3280                         return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
3281                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
3282                         return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
3283                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
3284                         return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
3285                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
3286                         return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
3287                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
3288                         return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
3289                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
3290                         return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
3291                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
3292                         return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
3293                 case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
3294                 default:
3295                         return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
3296         }
3297 }