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      1 /* libFLAC - Free Lossless Audio Codec library
      2  * Copyright (C) 2001-2009  Josh Coalson
      3  * Copyright (C) 2011-2016  Xiph.Org Foundation
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *
      9  * - Redistributions of source code must retain the above copyright
     10  * notice, this list of conditions and the following disclaimer.
     11  *
     12  * - Redistributions in binary form must reproduce the above copyright
     13  * notice, this list of conditions and the following disclaimer in the
     14  * documentation and/or other materials provided with the distribution.
     15  *
     16  * - Neither the name of the Xiph.org Foundation nor the names of its
     17  * contributors may be used to endorse or promote products derived from
     18  * this software without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
     24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #ifdef HAVE_CONFIG_H
     34 #  include <config.h>
     35 #endif
     36 
     37 #include <errno.h>
     38 #include <stdio.h>
     39 #include <stdlib.h>
     40 #include <string.h>
     41 #include <stdarg.h>
     42 
     43 #include <sys/stat.h> /* for stat(), maybe chmod() */
     44 
     45 #include "private/metadata.h"
     46 
     47 #include "FLAC/assert.h"
     48 #include "FLAC/stream_decoder.h"
     49 #include "share/alloc.h"
     50 #include "share/compat.h"
     51 #include "share/macros.h"
     52 #include "share/safe_str.h"
     53 #include "private/macros.h"
     54 #include "private/memory.h"
     55 
     56 /* Alias the first (in share/alloc.h) to the second (in src/libFLAC/memory.c). */
     57 #define safe_malloc_mul_2op_ safe_malloc_mul_2op_p
     58 
     59 /****************************************************************************
     60  *
     61  * Local function declarations
     62  *
     63  ***************************************************************************/
     64 
     65 static void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
     66 static void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes);
     67 static void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes);
     68 static FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes);
     69 static FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes);
     70 static FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes);
     71 
     72 static FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator);
     73 static FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block);
     74 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);
     75 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);
     76 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block);
     77 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);
     78 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);
     79 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);
     80 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, unsigned max_length);
     81 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_VorbisComment *block, unsigned block_length);
     82 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track);
     83 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block);
     84 static FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block);
     85 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);
     86 
     87 static FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
     88 static FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block);
     89 static FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
     90 static FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block);
     91 static FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block);
     92 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);
     93 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);
     94 static FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block);
     95 static FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block);
     96 static FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block);
     97 static FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block);
     98 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);
     99 
    100 static FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block);
    101 static FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last);
    102 static FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append);
    103 
    104 static void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator);
    105 static FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator);
    106 
    107 static unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb);
    108 static unsigned seek_to_first_metadata_block_(FILE *f);
    109 
    110 static FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append);
    111 static FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, FLAC__off_t fixup_is_last_flag_offset, FLAC__bool backup);
    112 
    113 static FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status);
    114 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, FLAC__off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status);
    115 static FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status);
    116 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);
    117 
    118 static FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
    119 static FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status);
    120 static void cleanup_tempfile_(FILE **tempfile, char **tempfilename);
    121 
    122 static FLAC__bool get_file_stats_(const char *filename, struct flac_stat_s *stats);
    123 static void set_file_stats_(const char *filename, struct flac_stat_s *stats);
    124 
    125 static int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence);
    126 static FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle);
    127 
    128 static FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status);
    129 
    130 
    131 #ifdef FLAC__VALGRIND_TESTING
    132 static size_t local__fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
    133 {
    134 	size_t ret = fwrite(ptr, size, nmemb, stream);
    135 	if(!ferror(stream))
    136 		fflush(stream);
    137 	return ret;
    138 }
    139 #else
    140 #define local__fwrite fwrite
    141 #endif
    142 
    143 /****************************************************************************
    144  *
    145  * Level 0 implementation
    146  *
    147  ***************************************************************************/
    148 
    149 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
    150 static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
    151 static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
    152 
    153 typedef struct {
    154 	FLAC__bool got_error;
    155 	FLAC__StreamMetadata *object;
    156 } level0_client_data;
    157 
    158 static FLAC__StreamMetadata *get_one_metadata_block_(const char *filename, FLAC__MetadataType type)
    159 {
    160 	level0_client_data cd;
    161 	FLAC__StreamDecoder *decoder;
    162 
    163 	FLAC__ASSERT(0 != filename);
    164 
    165 	cd.got_error = false;
    166 	cd.object = 0;
    167 
    168 	decoder = FLAC__stream_decoder_new();
    169 
    170 	if(0 == decoder)
    171 		return 0;
    172 
    173 	FLAC__stream_decoder_set_md5_checking(decoder, false);
    174 	FLAC__stream_decoder_set_metadata_ignore_all(decoder);
    175 	FLAC__stream_decoder_set_metadata_respond(decoder, type);
    176 
    177 	if(FLAC__stream_decoder_init_file(decoder, filename, write_callback_, metadata_callback_, error_callback_, &cd) != FLAC__STREAM_DECODER_INIT_STATUS_OK || cd.got_error) {
    178 		(void)FLAC__stream_decoder_finish(decoder);
    179 		FLAC__stream_decoder_delete(decoder);
    180 		return 0;
    181 	}
    182 
    183 	if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder) || cd.got_error) {
    184 		(void)FLAC__stream_decoder_finish(decoder);
    185 		FLAC__stream_decoder_delete(decoder);
    186 		if(0 != cd.object)
    187 			FLAC__metadata_object_delete(cd.object);
    188 		return 0;
    189 	}
    190 
    191 	(void)FLAC__stream_decoder_finish(decoder);
    192 	FLAC__stream_decoder_delete(decoder);
    193 
    194 	return cd.object;
    195 }
    196 
    197 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
    198 {
    199 	FLAC__StreamMetadata *object;
    200 
    201 	FLAC__ASSERT(0 != filename);
    202 	FLAC__ASSERT(0 != streaminfo);
    203 
    204 	object = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_STREAMINFO);
    205 
    206 	if (object) {
    207 		/* can just copy the contents since STREAMINFO has no internal structure */
    208 		*streaminfo = *object;
    209 		FLAC__metadata_object_delete(object);
    210 		return true;
    211 	}
    212 	else {
    213 		return false;
    214 	}
    215 }
    216 
    217 FLAC_API FLAC__bool FLAC__metadata_get_tags(const char *filename, FLAC__StreamMetadata **tags)
    218 {
    219 	FLAC__ASSERT(0 != filename);
    220 	FLAC__ASSERT(0 != tags);
    221 
    222 	*tags = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_VORBIS_COMMENT);
    223 
    224 	return 0 != *tags;
    225 }
    226 
    227 FLAC_API FLAC__bool FLAC__metadata_get_cuesheet(const char *filename, FLAC__StreamMetadata **cuesheet)
    228 {
    229 	FLAC__ASSERT(0 != filename);
    230 	FLAC__ASSERT(0 != cuesheet);
    231 
    232 	*cuesheet = get_one_metadata_block_(filename, FLAC__METADATA_TYPE_CUESHEET);
    233 
    234 	return 0 != *cuesheet;
    235 }
    236 
    237 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
    238 {
    239 	(void)decoder, (void)frame, (void)buffer, (void)client_data;
    240 
    241 	return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
    242 }
    243 
    244 void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
    245 {
    246 	level0_client_data *cd = (level0_client_data *)client_data;
    247 	(void)decoder;
    248 
    249 	/*
    250 	 * we assume we only get here when the one metadata block we were
    251 	 * looking for was passed to us
    252 	 */
    253 	if(!cd->got_error && 0 == cd->object) {
    254 		if(0 == (cd->object = FLAC__metadata_object_clone(metadata)))
    255 			cd->got_error = true;
    256 	}
    257 }
    258 
    259 void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
    260 {
    261 	level0_client_data *cd = (level0_client_data *)client_data;
    262 	(void)decoder;
    263 
    264 	if(status != FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
    265 		cd->got_error = true;
    266 }
    267 
    268 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)
    269 {
    270 	FLAC__Metadata_SimpleIterator *it;
    271 	FLAC__uint64 max_area_seen = 0;
    272 	FLAC__uint64 max_depth_seen = 0;
    273 
    274 	FLAC__ASSERT(0 != filename);
    275 	FLAC__ASSERT(0 != picture);
    276 
    277 	*picture = 0;
    278 
    279 	it = FLAC__metadata_simple_iterator_new();
    280 	if(0 == it)
    281 		return false;
    282 	if(!FLAC__metadata_simple_iterator_init(it, filename, /*read_only=*/true, /*preserve_file_stats=*/true)) {
    283 		FLAC__metadata_simple_iterator_delete(it);
    284 		return false;
    285 	}
    286 	do {
    287 		if(FLAC__metadata_simple_iterator_get_block_type(it) == FLAC__METADATA_TYPE_PICTURE) {
    288 			FLAC__StreamMetadata *obj = FLAC__metadata_simple_iterator_get_block(it);
    289 			FLAC__uint64 area = (FLAC__uint64)obj->data.picture.width * (FLAC__uint64)obj->data.picture.height;
    290 			/* check constraints */
    291 			if(
    292 				(type == (FLAC__StreamMetadata_Picture_Type)(-1) || type == obj->data.picture.type) &&
    293 				(mime_type == 0 || !strcmp(mime_type, obj->data.picture.mime_type)) &&
    294 				(description == 0 || !strcmp((const char *)description, (const char *)obj->data.picture.description)) &&
    295 				obj->data.picture.width <= max_width &&
    296 				obj->data.picture.height <= max_height &&
    297 				obj->data.picture.depth <= max_depth &&
    298 				obj->data.picture.colors <= max_colors &&
    299 				(area > max_area_seen || (area == max_area_seen && obj->data.picture.depth > max_depth_seen))
    300 			) {
    301 				if(*picture)
    302 					FLAC__metadata_object_delete(*picture);
    303 				*picture = obj;
    304 				max_area_seen = area;
    305 				max_depth_seen = obj->data.picture.depth;
    306 			}
    307 			else {
    308 				FLAC__metadata_object_delete(obj);
    309 			}
    310 		}
    311 	} while(FLAC__metadata_simple_iterator_next(it));
    312 
    313 	FLAC__metadata_simple_iterator_delete(it);
    314 
    315 	return (0 != *picture);
    316 }
    317 
    318 
    319 /****************************************************************************
    320  *
    321  * Level 1 implementation
    322  *
    323  ***************************************************************************/
    324 
    325 #define SIMPLE_ITERATOR_MAX_PUSH_DEPTH (1+4)
    326 /* 1 for initial offset, +4 for our own personal use */
    327 
    328 struct FLAC__Metadata_SimpleIterator {
    329 	FILE *file;
    330 	char *filename, *tempfile_path_prefix;
    331 	struct flac_stat_s stats;
    332 	FLAC__bool has_stats;
    333 	FLAC__bool is_writable;
    334 	FLAC__Metadata_SimpleIteratorStatus status;
    335 	FLAC__off_t offset[SIMPLE_ITERATOR_MAX_PUSH_DEPTH];
    336 	FLAC__off_t first_offset; /* this is the offset to the STREAMINFO block */
    337 	unsigned depth;
    338 	/* this is the metadata block header of the current block we are pointing to: */
    339 	FLAC__bool is_last;
    340 	FLAC__MetadataType type;
    341 	unsigned length;
    342 };
    343 
    344 FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
    345 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK",
    346 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT",
    347 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE",
    348 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE",
    349 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE",
    350 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA",
    351 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR",
    352 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR",
    353 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR",
    354 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR",
    355 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR",
    356 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR",
    357 	"FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR"
    358 };
    359 
    360 
    361 FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new(void)
    362 {
    363 	FLAC__Metadata_SimpleIterator *iterator = calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
    364 
    365 	if(0 != iterator) {
    366 		iterator->file = 0;
    367 		iterator->filename = 0;
    368 		iterator->tempfile_path_prefix = 0;
    369 		iterator->has_stats = false;
    370 		iterator->is_writable = false;
    371 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
    372 		iterator->first_offset = iterator->offset[0] = -1;
    373 		iterator->depth = 0;
    374 	}
    375 
    376 	return iterator;
    377 }
    378 
    379 static void simple_iterator_free_guts_(FLAC__Metadata_SimpleIterator *iterator)
    380 {
    381 	FLAC__ASSERT(0 != iterator);
    382 
    383 	if(0 != iterator->file) {
    384 		fclose(iterator->file);
    385 		iterator->file = 0;
    386 		if(iterator->has_stats)
    387 			set_file_stats_(iterator->filename, &iterator->stats);
    388 	}
    389 	if(0 != iterator->filename) {
    390 		free(iterator->filename);
    391 		iterator->filename = 0;
    392 	}
    393 	if(0 != iterator->tempfile_path_prefix) {
    394 		free(iterator->tempfile_path_prefix);
    395 		iterator->tempfile_path_prefix = 0;
    396 	}
    397 }
    398 
    399 FLAC_API void FLAC__metadata_simple_iterator_delete(FLAC__Metadata_SimpleIterator *iterator)
    400 {
    401 	FLAC__ASSERT(0 != iterator);
    402 
    403 	simple_iterator_free_guts_(iterator);
    404 	free(iterator);
    405 }
    406 
    407 FLAC_API FLAC__Metadata_SimpleIteratorStatus FLAC__metadata_simple_iterator_status(FLAC__Metadata_SimpleIterator *iterator)
    408 {
    409 	FLAC__Metadata_SimpleIteratorStatus status;
    410 
    411 	FLAC__ASSERT(0 != iterator);
    412 
    413 	status = iterator->status;
    414 	iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
    415 	return status;
    416 }
    417 
    418 static FLAC__bool simple_iterator_prime_input_(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool read_only)
    419 {
    420 	unsigned ret;
    421 
    422 	FLAC__ASSERT(0 != iterator);
    423 
    424 	if(read_only || 0 == (iterator->file = flac_fopen(iterator->filename, "r+b"))) {
    425 		iterator->is_writable = false;
    426 		if(read_only || errno == EACCES) {
    427 			if(0 == (iterator->file = flac_fopen(iterator->filename, "rb"))) {
    428 				iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
    429 				return false;
    430 			}
    431 		}
    432 		else {
    433 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
    434 			return false;
    435 		}
    436 	}
    437 	else {
    438 		iterator->is_writable = true;
    439 	}
    440 
    441 	ret = seek_to_first_metadata_block_(iterator->file);
    442 	switch(ret) {
    443 		case 0:
    444 			iterator->depth = 0;
    445 			iterator->first_offset = iterator->offset[iterator->depth] = ftello(iterator->file);
    446 			return read_metadata_block_header_(iterator);
    447 		case 1:
    448 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
    449 			return false;
    450 		case 2:
    451 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    452 			return false;
    453 		case 3:
    454 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE;
    455 			return false;
    456 		default:
    457 			FLAC__ASSERT(0);
    458 			return false;
    459 	}
    460 }
    461 
    462 #if 0
    463 @@@ If we decide to finish implementing this, put this comment back in metadata.h
    464 /*
    465  * The 'tempfile_path_prefix' allows you to specify a directory where
    466  * tempfiles should go.  Remember that if your metadata edits cause the
    467  * FLAC file to grow, the entire file will have to be rewritten.  If
    468  * 'tempfile_path_prefix' is NULL, the temp file will be written in the
    469  * same directory as the original FLAC file.  This makes replacing the
    470  * original with the tempfile fast but requires extra space in the same
    471  * partition for the tempfile.  If space is a problem, you can pass a
    472  * directory name belonging to a different partition in
    473  * 'tempfile_path_prefix'.  Note that you should use the forward slash
    474  * '/' as the directory separator.  A trailing slash is not needed; it
    475  * will be added automatically.
    476  */
    477 FLAC__bool FLAC__metadata_simple_iterator_init(FLAC__Metadata_SimpleIterator *iterator, const char *filename, FLAC__bool preserve_file_stats, const char *tempfile_path_prefix);
    478 #endif
    479 
    480 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)
    481 {
    482 	const char *tempfile_path_prefix = 0; /*@@@ search for comments near 'flac_rename(...)' for what it will take to finish implementing this */
    483 
    484 	FLAC__ASSERT(0 != iterator);
    485 	FLAC__ASSERT(0 != filename);
    486 
    487 	simple_iterator_free_guts_(iterator);
    488 
    489 	if(!read_only && preserve_file_stats)
    490 		iterator->has_stats = get_file_stats_(filename, &iterator->stats);
    491 
    492 	if(0 == (iterator->filename = strdup(filename))) {
    493 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
    494 		return false;
    495 	}
    496 	if(0 != tempfile_path_prefix && 0 == (iterator->tempfile_path_prefix = strdup(tempfile_path_prefix))) {
    497 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
    498 		return false;
    499 	}
    500 
    501 	return simple_iterator_prime_input_(iterator, read_only);
    502 }
    503 
    504 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_writable(const FLAC__Metadata_SimpleIterator *iterator)
    505 {
    506 	FLAC__ASSERT(0 != iterator);
    507 	FLAC__ASSERT(0 != iterator->file);
    508 
    509 	return iterator->is_writable;
    510 }
    511 
    512 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_next(FLAC__Metadata_SimpleIterator *iterator)
    513 {
    514 	FLAC__ASSERT(0 != iterator);
    515 	FLAC__ASSERT(0 != iterator->file);
    516 
    517 	if(iterator->is_last)
    518 		return false;
    519 
    520 	if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
    521 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    522 		return false;
    523 	}
    524 
    525 	iterator->offset[iterator->depth] = ftello(iterator->file);
    526 
    527 	return read_metadata_block_header_(iterator);
    528 }
    529 
    530 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_prev(FLAC__Metadata_SimpleIterator *iterator)
    531 {
    532 	FLAC__off_t this_offset;
    533 
    534 	FLAC__ASSERT(0 != iterator);
    535 	FLAC__ASSERT(0 != iterator->file);
    536 
    537 	if(iterator->offset[iterator->depth] == iterator->first_offset)
    538 		return false;
    539 
    540 	if(0 != fseeko(iterator->file, iterator->first_offset, SEEK_SET)) {
    541 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    542 		return false;
    543 	}
    544 	this_offset = iterator->first_offset;
    545 	if(!read_metadata_block_header_(iterator))
    546 		return false;
    547 
    548 	/* we ignore any error from ftello() and catch it in fseeko() */
    549 	while(ftello(iterator->file) + (FLAC__off_t)iterator->length < iterator->offset[iterator->depth]) {
    550 		if(0 != fseeko(iterator->file, iterator->length, SEEK_CUR)) {
    551 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    552 			return false;
    553 		}
    554 		this_offset = ftello(iterator->file);
    555 		if(!read_metadata_block_header_(iterator))
    556 			return false;
    557 	}
    558 
    559 	iterator->offset[iterator->depth] = this_offset;
    560 
    561 	return true;
    562 }
    563 
    564 /*@@@@add to tests*/
    565 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_is_last(const FLAC__Metadata_SimpleIterator *iterator)
    566 {
    567 	FLAC__ASSERT(0 != iterator);
    568 	FLAC__ASSERT(0 != iterator->file);
    569 
    570 	return iterator->is_last;
    571 }
    572 
    573 /*@@@@add to tests*/
    574 FLAC_API off_t FLAC__metadata_simple_iterator_get_block_offset(const FLAC__Metadata_SimpleIterator *iterator)
    575 {
    576 	FLAC__ASSERT(0 != iterator);
    577 	FLAC__ASSERT(0 != iterator->file);
    578 
    579 	return iterator->offset[iterator->depth];
    580 }
    581 
    582 FLAC_API FLAC__MetadataType FLAC__metadata_simple_iterator_get_block_type(const FLAC__Metadata_SimpleIterator *iterator)
    583 {
    584 	FLAC__ASSERT(0 != iterator);
    585 	FLAC__ASSERT(0 != iterator->file);
    586 
    587 	return iterator->type;
    588 }
    589 
    590 /*@@@@add to tests*/
    591 FLAC_API unsigned FLAC__metadata_simple_iterator_get_block_length(const FLAC__Metadata_SimpleIterator *iterator)
    592 {
    593 	FLAC__ASSERT(0 != iterator);
    594 	FLAC__ASSERT(0 != iterator->file);
    595 
    596 	return iterator->length;
    597 }
    598 
    599 /*@@@@add to tests*/
    600 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_get_application_id(FLAC__Metadata_SimpleIterator *iterator, FLAC__byte *id)
    601 {
    602 	const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
    603 
    604 	FLAC__ASSERT(0 != iterator);
    605 	FLAC__ASSERT(0 != iterator->file);
    606 	FLAC__ASSERT(0 != id);
    607 
    608 	if(iterator->type != FLAC__METADATA_TYPE_APPLICATION) {
    609 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
    610 		return false;
    611 	}
    612 
    613 	if(fread(id, 1, id_bytes, iterator->file) != id_bytes) {
    614 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
    615 		return false;
    616 	}
    617 
    618 	/* back up */
    619 	if(0 != fseeko(iterator->file, -((int)id_bytes), SEEK_CUR)) {
    620 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    621 		return false;
    622 	}
    623 
    624 	return true;
    625 }
    626 
    627 FLAC_API FLAC__StreamMetadata *FLAC__metadata_simple_iterator_get_block(FLAC__Metadata_SimpleIterator *iterator)
    628 {
    629 	FLAC__StreamMetadata *block = FLAC__metadata_object_new(iterator->type);
    630 
    631 	FLAC__ASSERT(0 != iterator);
    632 	FLAC__ASSERT(0 != iterator->file);
    633 
    634 	if(0 != block) {
    635 		block->is_last = iterator->is_last;
    636 		block->length = iterator->length;
    637 
    638 		if(!read_metadata_block_data_(iterator, block)) {
    639 			FLAC__metadata_object_delete(block);
    640 			return 0;
    641 		}
    642 
    643 		/* back up to the beginning of the block data to stay consistent */
    644 		if(0 != fseeko(iterator->file, iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH, SEEK_SET)) {
    645 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
    646 			FLAC__metadata_object_delete(block);
    647 			return 0;
    648 		}
    649 	}
    650 	else
    651 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
    652 
    653 	return block;
    654 }
    655 
    656 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_set_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
    657 {
    658 	FLAC__ASSERT_DECLARATION(FLAC__off_t debug_target_offset = iterator->offset[iterator->depth];)
    659 	FLAC__bool ret;
    660 
    661 	FLAC__ASSERT(0 != iterator);
    662 	FLAC__ASSERT(0 != iterator->file);
    663 	FLAC__ASSERT(0 != block);
    664 
    665 	if(!iterator->is_writable) {
    666 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
    667 		return false;
    668 	}
    669 
    670 	if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO || block->type == FLAC__METADATA_TYPE_STREAMINFO) {
    671 		if(iterator->type != block->type) {
    672 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
    673 			return false;
    674 		}
    675 	}
    676 
    677 	block->is_last = iterator->is_last;
    678 
    679 	if(iterator->length == block->length)
    680 		return write_metadata_block_stationary_(iterator, block);
    681 	else if(iterator->length > block->length) {
    682 		if(use_padding && iterator->length >= FLAC__STREAM_METADATA_HEADER_LENGTH + block->length) {
    683 			ret = write_metadata_block_stationary_with_padding_(iterator, block, iterator->length - FLAC__STREAM_METADATA_HEADER_LENGTH - block->length, block->is_last);
    684 			FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
    685 			FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    686 			return ret;
    687 		}
    688 		else {
    689 			ret = rewrite_whole_file_(iterator, block, /*append=*/false);
    690 			FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
    691 			FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    692 			return ret;
    693 		}
    694 	}
    695 	else /* iterator->length < block->length */ {
    696 		unsigned padding_leftover = 0;
    697 		FLAC__bool padding_is_last = false;
    698 		if(use_padding) {
    699 			/* first see if we can even use padding */
    700 			if(iterator->is_last) {
    701 				use_padding = false;
    702 			}
    703 			else {
    704 				const unsigned extra_padding_bytes_required = block->length - iterator->length;
    705 				simple_iterator_push_(iterator);
    706 				if(!FLAC__metadata_simple_iterator_next(iterator)) {
    707 					(void)simple_iterator_pop_(iterator);
    708 					return false;
    709 				}
    710 				if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
    711 					use_padding = false;
    712 				}
    713 				else {
    714 					if(FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length == extra_padding_bytes_required) {
    715 						padding_leftover = 0;
    716 						block->is_last = iterator->is_last;
    717 					}
    718 					else if(iterator->length < extra_padding_bytes_required)
    719 						use_padding = false;
    720 					else {
    721 						padding_leftover = FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length - extra_padding_bytes_required;
    722 						padding_is_last = iterator->is_last;
    723 						block->is_last = false;
    724 					}
    725 				}
    726 				if(!simple_iterator_pop_(iterator))
    727 					return false;
    728 			}
    729 		}
    730 		if(use_padding) {
    731 			if(padding_leftover == 0) {
    732 				ret = write_metadata_block_stationary_(iterator, block);
    733 				FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
    734 				FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    735 				return ret;
    736 			}
    737 			else {
    738 				FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
    739 				ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
    740 				FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
    741 				FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    742 				return ret;
    743 			}
    744 		}
    745 		else {
    746 			ret = rewrite_whole_file_(iterator, block, /*append=*/false);
    747 			FLAC__ASSERT(!ret || iterator->offset[iterator->depth] == debug_target_offset);
    748 			FLAC__ASSERT(!ret || ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    749 			return ret;
    750 		}
    751 	}
    752 }
    753 
    754 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_insert_block_after(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool use_padding)
    755 {
    756 	unsigned padding_leftover = 0;
    757 	FLAC__bool padding_is_last = false;
    758 
    759 	FLAC__ASSERT_DECLARATION(FLAC__off_t debug_target_offset = iterator->offset[iterator->depth] + FLAC__STREAM_METADATA_HEADER_LENGTH + iterator->length;)
    760 	FLAC__bool ret;
    761 
    762 	FLAC__ASSERT(0 != iterator);
    763 	FLAC__ASSERT(0 != iterator->file);
    764 	FLAC__ASSERT(0 != block);
    765 
    766 	if(!iterator->is_writable) {
    767 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
    768 		return false;
    769 	}
    770 
    771 	if(block->type == FLAC__METADATA_TYPE_STREAMINFO) {
    772 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
    773 		return false;
    774 	}
    775 
    776 	block->is_last = iterator->is_last;
    777 
    778 	if(use_padding) {
    779 		/* first see if we can even use padding */
    780 		if(iterator->is_last) {
    781 			use_padding = false;
    782 		}
    783 		else {
    784 			simple_iterator_push_(iterator);
    785 			if(!FLAC__metadata_simple_iterator_next(iterator)) {
    786 				(void)simple_iterator_pop_(iterator);
    787 				return false;
    788 			}
    789 			if(iterator->type != FLAC__METADATA_TYPE_PADDING) {
    790 				use_padding = false;
    791 			}
    792 			else {
    793 				if(iterator->length == block->length) {
    794 					padding_leftover = 0;
    795 					block->is_last = iterator->is_last;
    796 				}
    797 				else if(iterator->length < FLAC__STREAM_METADATA_HEADER_LENGTH + block->length)
    798 					use_padding = false;
    799 				else {
    800 					padding_leftover = iterator->length - block->length;
    801 					padding_is_last = iterator->is_last;
    802 					block->is_last = false;
    803 				}
    804 			}
    805 			if(!simple_iterator_pop_(iterator))
    806 				return false;
    807 		}
    808 	}
    809 	if(use_padding) {
    810 		/* move to the next block, which is suitable padding */
    811 		if(!FLAC__metadata_simple_iterator_next(iterator))
    812 			return false;
    813 		if(padding_leftover == 0) {
    814 			ret = write_metadata_block_stationary_(iterator, block);
    815 			FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
    816 			FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    817 			return ret;
    818 		}
    819 		else {
    820 			FLAC__ASSERT(padding_leftover >= FLAC__STREAM_METADATA_HEADER_LENGTH);
    821 			ret = write_metadata_block_stationary_with_padding_(iterator, block, padding_leftover - FLAC__STREAM_METADATA_HEADER_LENGTH, padding_is_last);
    822 			FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
    823 			FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    824 			return ret;
    825 		}
    826 	}
    827 	else {
    828 		ret = rewrite_whole_file_(iterator, block, /*append=*/true);
    829 		FLAC__ASSERT(iterator->offset[iterator->depth] == debug_target_offset);
    830 		FLAC__ASSERT(ftello(iterator->file) == debug_target_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
    831 		return ret;
    832 	}
    833 }
    834 
    835 FLAC_API FLAC__bool FLAC__metadata_simple_iterator_delete_block(FLAC__Metadata_SimpleIterator *iterator, FLAC__bool use_padding)
    836 {
    837 	FLAC__ASSERT_DECLARATION(FLAC__off_t debug_target_offset = iterator->offset[iterator->depth];)
    838 	FLAC__bool ret;
    839 
    840 	if(!iterator->is_writable) {
    841 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE;
    842 		return false;
    843 	}
    844 
    845 	if(iterator->type == FLAC__METADATA_TYPE_STREAMINFO) {
    846 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT;
    847 		return false;
    848 	}
    849 
    850 	if(use_padding) {
    851 		FLAC__StreamMetadata *padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
    852 		if(0 == padding) {
    853 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
    854 			return false;
    855 		}
    856 		padding->length = iterator->length;
    857 		if(!FLAC__metadata_simple_iterator_set_block(iterator, padding, false)) {
    858 			FLAC__metadata_object_delete(padding);
    859 			return false;
    860 		}
    861 		FLAC__metadata_object_delete(padding);
    862 		if(!FLAC__metadata_simple_iterator_prev(iterator))
    863 			return false;
    864 		FLAC__ASSERT(iterator->offset[iterator->depth] + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (FLAC__off_t)iterator->length == debug_target_offset);
    865 		FLAC__ASSERT(ftello(iterator->file) + (FLAC__off_t)iterator->length == debug_target_offset);
    866 		return true;
    867 	}
    868 	else {
    869 		ret = rewrite_whole_file_(iterator, 0, /*append=*/false);
    870 		FLAC__ASSERT(iterator->offset[iterator->depth] + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (FLAC__off_t)iterator->length == debug_target_offset);
    871 		FLAC__ASSERT(ftello(iterator->file) + (FLAC__off_t)iterator->length == debug_target_offset);
    872 		return ret;
    873 	}
    874 }
    875 
    876 
    877 
    878 /****************************************************************************
    879  *
    880  * Level 2 implementation
    881  *
    882  ***************************************************************************/
    883 
    884 
    885 typedef struct FLAC__Metadata_Node {
    886 	FLAC__StreamMetadata *data;
    887 	struct FLAC__Metadata_Node *prev, *next;
    888 } FLAC__Metadata_Node;
    889 
    890 struct FLAC__Metadata_Chain {
    891 	char *filename; /* will be NULL if using callbacks */
    892 	FLAC__bool is_ogg;
    893 	FLAC__Metadata_Node *head;
    894 	FLAC__Metadata_Node *tail;
    895 	unsigned nodes;
    896 	FLAC__Metadata_ChainStatus status;
    897 	FLAC__off_t first_offset, last_offset;
    898 	/*
    899 	 * This is the length of the chain initially read from the FLAC file.
    900 	 * it is used to compare against the current length to decide whether
    901 	 * or not the whole file has to be rewritten.
    902 	 */
    903 	FLAC__off_t initial_length;
    904 	/* @@@ hacky, these are currently only needed by ogg reader */
    905 	FLAC__IOHandle handle;
    906 	FLAC__IOCallback_Read read_cb;
    907 };
    908 
    909 struct FLAC__Metadata_Iterator {
    910 	FLAC__Metadata_Chain *chain;
    911 	FLAC__Metadata_Node *current;
    912 };
    913 
    914 FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
    915 	"FLAC__METADATA_CHAIN_STATUS_OK",
    916 	"FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT",
    917 	"FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE",
    918 	"FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE",
    919 	"FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE",
    920 	"FLAC__METADATA_CHAIN_STATUS_BAD_METADATA",
    921 	"FLAC__METADATA_CHAIN_STATUS_READ_ERROR",
    922 	"FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR",
    923 	"FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR",
    924 	"FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR",
    925 	"FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR",
    926 	"FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR",
    927 	"FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR",
    928 	"FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS",
    929 	"FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH",
    930 	"FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL"
    931 };
    932 
    933 
    934 static FLAC__Metadata_Node *node_new_(void)
    935 {
    936 	return calloc(1, sizeof(FLAC__Metadata_Node));
    937 }
    938 
    939 static void node_delete_(FLAC__Metadata_Node *node)
    940 {
    941 	FLAC__ASSERT(0 != node);
    942 	if(0 != node->data)
    943 		FLAC__metadata_object_delete(node->data);
    944 	free(node);
    945 }
    946 
    947 static void chain_init_(FLAC__Metadata_Chain *chain)
    948 {
    949 	FLAC__ASSERT(0 != chain);
    950 
    951 	chain->filename = 0;
    952 	chain->is_ogg = false;
    953 	chain->head = chain->tail = 0;
    954 	chain->nodes = 0;
    955 	chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
    956 	chain->initial_length = 0;
    957 	chain->read_cb = 0;
    958 }
    959 
    960 static void chain_clear_(FLAC__Metadata_Chain *chain)
    961 {
    962 	FLAC__Metadata_Node *node, *next;
    963 
    964 	FLAC__ASSERT(0 != chain);
    965 
    966 	for(node = chain->head; node; ) {
    967 		next = node->next;
    968 		node_delete_(node);
    969 		node = next;
    970 	}
    971 
    972 	if(0 != chain->filename)
    973 		free(chain->filename);
    974 
    975 	chain_init_(chain);
    976 }
    977 
    978 static void chain_append_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
    979 {
    980 	FLAC__ASSERT(0 != chain);
    981 	FLAC__ASSERT(0 != node);
    982 	FLAC__ASSERT(0 != node->data);
    983 
    984 	node->next = node->prev = 0;
    985 	node->data->is_last = true;
    986 	if(0 != chain->tail)
    987 		chain->tail->data->is_last = false;
    988 
    989 	if(0 == chain->head)
    990 		chain->head = node;
    991 	else {
    992 		FLAC__ASSERT(0 != chain->tail);
    993 		chain->tail->next = node;
    994 		node->prev = chain->tail;
    995 	}
    996 	chain->tail = node;
    997 	chain->nodes++;
    998 }
    999 
   1000 static void chain_remove_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
   1001 {
   1002 	FLAC__ASSERT(0 != chain);
   1003 	FLAC__ASSERT(0 != node);
   1004 
   1005 	if(node == chain->head)
   1006 		chain->head = node->next;
   1007 	else
   1008 		node->prev->next = node->next;
   1009 
   1010 	if(node == chain->tail)
   1011 		chain->tail = node->prev;
   1012 	else
   1013 		node->next->prev = node->prev;
   1014 
   1015 	if(0 != chain->tail)
   1016 		chain->tail->data->is_last = true;
   1017 
   1018 	chain->nodes--;
   1019 }
   1020 
   1021 static void chain_delete_node_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
   1022 {
   1023 	chain_remove_node_(chain, node);
   1024 	node_delete_(node);
   1025 }
   1026 
   1027 static FLAC__off_t chain_calculate_length_(FLAC__Metadata_Chain *chain)
   1028 {
   1029 	const FLAC__Metadata_Node *node;
   1030 	FLAC__off_t length = 0;
   1031 	for(node = chain->head; node; node = node->next)
   1032 		length += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
   1033 	return length;
   1034 }
   1035 
   1036 static void iterator_insert_node_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
   1037 {
   1038 	FLAC__ASSERT(0 != node);
   1039 	FLAC__ASSERT(0 != node->data);
   1040 	FLAC__ASSERT(0 != iterator);
   1041 	FLAC__ASSERT(0 != iterator->current);
   1042 	FLAC__ASSERT(0 != iterator->chain);
   1043 	FLAC__ASSERT(0 != iterator->chain->head);
   1044 	FLAC__ASSERT(0 != iterator->chain->tail);
   1045 
   1046 	node->data->is_last = false;
   1047 
   1048 	node->prev = iterator->current->prev;
   1049 	node->next = iterator->current;
   1050 
   1051 	if(0 == node->prev)
   1052 		iterator->chain->head = node;
   1053 	else
   1054 		node->prev->next = node;
   1055 
   1056 	iterator->current->prev = node;
   1057 
   1058 	iterator->chain->nodes++;
   1059 }
   1060 
   1061 static void iterator_insert_node_after_(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Node *node)
   1062 {
   1063 	FLAC__ASSERT(0 != node);
   1064 	FLAC__ASSERT(0 != node->data);
   1065 	FLAC__ASSERT(0 != iterator);
   1066 	FLAC__ASSERT(0 != iterator->current);
   1067 	FLAC__ASSERT(0 != iterator->chain);
   1068 	FLAC__ASSERT(0 != iterator->chain->head);
   1069 	FLAC__ASSERT(0 != iterator->chain->tail);
   1070 
   1071 	iterator->current->data->is_last = false;
   1072 
   1073 	node->prev = iterator->current;
   1074 	node->next = iterator->current->next;
   1075 
   1076 	if(0 == node->next)
   1077 		iterator->chain->tail = node;
   1078 	else
   1079 		node->next->prev = node;
   1080 
   1081 	node->prev->next = node;
   1082 
   1083 	iterator->chain->tail->data->is_last = true;
   1084 
   1085 	iterator->chain->nodes++;
   1086 }
   1087 
   1088 /* return true iff node and node->next are both padding */
   1089 static FLAC__bool chain_merge_adjacent_padding_(FLAC__Metadata_Chain *chain, FLAC__Metadata_Node *node)
   1090 {
   1091 	if(node->data->type == FLAC__METADATA_TYPE_PADDING && 0 != node->next && node->next->data->type == FLAC__METADATA_TYPE_PADDING) {
   1092 		const unsigned growth = FLAC__STREAM_METADATA_HEADER_LENGTH + node->next->data->length;
   1093 		node->data->length += growth; /* new block size can be greater than max metadata block size, but it'll be fixed later in chain_prepare_for_write_() */
   1094 
   1095 		chain_delete_node_(chain, node->next);
   1096 		return true;
   1097 	}
   1098 	else
   1099 		return false;
   1100 }
   1101 
   1102 /* Returns the new length of the chain, or 0 if there was an error. */
   1103 /* WATCHOUT: This can get called multiple times before a write, so
   1104  * it should still work when this happens.
   1105  */
   1106 /* WATCHOUT: Make sure to also update the logic in
   1107  * FLAC__metadata_chain_check_if_tempfile_needed() if the logic here changes.
   1108  */
   1109 static FLAC__off_t chain_prepare_for_write_(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
   1110 {
   1111 	FLAC__off_t current_length = chain_calculate_length_(chain);
   1112 
   1113 	if(use_padding) {
   1114 		/* if the metadata shrank and the last block is padding, we just extend the last padding block */
   1115 		if(current_length < chain->initial_length && chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
   1116 			const FLAC__off_t delta = chain->initial_length - current_length;
   1117 			chain->tail->data->length += delta;
   1118 			current_length += delta;
   1119 			FLAC__ASSERT(current_length == chain->initial_length);
   1120 		}
   1121 		/* if the metadata shrank more than 4 bytes then there's room to add another padding block */
   1122 		else if(current_length + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
   1123 			FLAC__StreamMetadata *padding;
   1124 			FLAC__Metadata_Node *node;
   1125 			if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING))) {
   1126 				chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1127 				return 0;
   1128 			}
   1129 			padding->length = chain->initial_length - (FLAC__STREAM_METADATA_HEADER_LENGTH + current_length);
   1130 			if(0 == (node = node_new_())) {
   1131 				FLAC__metadata_object_delete(padding);
   1132 				chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1133 				return 0;
   1134 			}
   1135 			node->data = padding;
   1136 			chain_append_node_(chain, node);
   1137 			current_length = chain_calculate_length_(chain);
   1138 			FLAC__ASSERT(current_length == chain->initial_length);
   1139 		}
   1140 		/* 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 */
   1141 		else if(current_length > chain->initial_length) {
   1142 			const FLAC__off_t delta = current_length - chain->initial_length;
   1143 			if(chain->tail->data->type == FLAC__METADATA_TYPE_PADDING) {
   1144 				/* if the delta is exactly the size of the last padding block, remove the padding block */
   1145 				if((FLAC__off_t)chain->tail->data->length + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
   1146 					chain_delete_node_(chain, chain->tail);
   1147 					current_length = chain_calculate_length_(chain);
   1148 					FLAC__ASSERT(current_length == chain->initial_length);
   1149 				}
   1150 				/* if there is at least 'delta' bytes of padding, trim the padding down */
   1151 				else if((FLAC__off_t)chain->tail->data->length >= delta) {
   1152 					chain->tail->data->length -= delta;
   1153 					current_length -= delta;
   1154 					FLAC__ASSERT(current_length == chain->initial_length);
   1155 				}
   1156 			}
   1157 		}
   1158 	}
   1159 
   1160 	/* check sizes of all metadata blocks; reduce padding size if necessary */
   1161 	{
   1162 		FLAC__Metadata_Node *node;
   1163 		for (node = chain->head; node; node = node->next) {
   1164 			if(node->data->length >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN)) {
   1165 				if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
   1166 					node->data->length = (1u << FLAC__STREAM_METADATA_LENGTH_LEN) - 1;
   1167 					current_length = chain_calculate_length_(chain);
   1168 				} else {
   1169 					chain->status = FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
   1170 					return 0;
   1171 				}
   1172 			}
   1173 		}
   1174 	}
   1175 
   1176 	return current_length;
   1177 }
   1178 
   1179 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)
   1180 {
   1181 	FLAC__Metadata_Node *node;
   1182 
   1183 	FLAC__ASSERT(0 != chain);
   1184 
   1185 	/* we assume we're already at the beginning of the file */
   1186 
   1187 	switch(seek_to_first_metadata_block_cb_(handle, read_cb, seek_cb)) {
   1188 		case 0:
   1189 			break;
   1190 		case 1:
   1191 			chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
   1192 			return false;
   1193 		case 2:
   1194 			chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1195 			return false;
   1196 		case 3:
   1197 			chain->status = FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
   1198 			return false;
   1199 		default:
   1200 			FLAC__ASSERT(0);
   1201 			return false;
   1202 	}
   1203 
   1204 	{
   1205 		FLAC__int64 pos = tell_cb(handle);
   1206 		if(pos < 0) {
   1207 			chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
   1208 			return false;
   1209 		}
   1210 		chain->first_offset = (FLAC__off_t)pos;
   1211 	}
   1212 
   1213 	{
   1214 		FLAC__bool is_last;
   1215 		FLAC__MetadataType type;
   1216 		unsigned length;
   1217 
   1218 		do {
   1219 			node = node_new_();
   1220 			if(0 == node) {
   1221 				chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1222 				return false;
   1223 			}
   1224 
   1225 			if(!read_metadata_block_header_cb_(handle, read_cb, &is_last, &type, &length)) {
   1226 				node_delete_(node);
   1227 				chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
   1228 				return false;
   1229 			}
   1230 
   1231 			node->data = FLAC__metadata_object_new(type);
   1232 			if(0 == node->data) {
   1233 				node_delete_(node);
   1234 				chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1235 				return false;
   1236 			}
   1237 
   1238 			node->data->is_last = is_last;
   1239 			node->data->length = length;
   1240 
   1241 			chain->status = get_equivalent_status_(read_metadata_block_data_cb_(handle, read_cb, seek_cb, node->data));
   1242 			if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
   1243 				node_delete_(node);
   1244 				return false;
   1245 			}
   1246 			chain_append_node_(chain, node);
   1247 		} while(!is_last);
   1248 	}
   1249 
   1250 	{
   1251 		FLAC__int64 pos = tell_cb(handle);
   1252 		if(pos < 0) {
   1253 			chain->status = FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
   1254 			return false;
   1255 		}
   1256 		chain->last_offset = (FLAC__off_t)pos;
   1257 	}
   1258 
   1259 	chain->initial_length = chain_calculate_length_(chain);
   1260 
   1261 	return true;
   1262 }
   1263 
   1264 static FLAC__StreamDecoderReadStatus chain_read_ogg_read_cb_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
   1265 {
   1266 	FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
   1267 	(void)decoder;
   1268 	if(*bytes > 0 && chain->status == FLAC__METADATA_CHAIN_STATUS_OK) {
   1269 		*bytes = chain->read_cb(buffer, sizeof(FLAC__byte), *bytes, chain->handle);
   1270 		if(*bytes == 0)
   1271 			return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
   1272 		else
   1273 			return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
   1274 	}
   1275 	else
   1276 		return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
   1277 }
   1278 
   1279 static FLAC__StreamDecoderWriteStatus chain_read_ogg_write_cb_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
   1280 {
   1281 	(void)decoder, (void)frame, (void)buffer, (void)client_data;
   1282 	return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
   1283 }
   1284 
   1285 static void chain_read_ogg_metadata_cb_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
   1286 {
   1287 	FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
   1288 	FLAC__Metadata_Node *node;
   1289 
   1290 	(void)decoder;
   1291 
   1292 	node = node_new_();
   1293 	if(0 == node) {
   1294 		chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1295 		return;
   1296 	}
   1297 
   1298 	node->data = FLAC__metadata_object_clone(metadata);
   1299 	if(0 == node->data) {
   1300 		node_delete_(node);
   1301 		chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1302 		return;
   1303 	}
   1304 
   1305 	chain_append_node_(chain, node);
   1306 }
   1307 
   1308 static void chain_read_ogg_error_cb_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
   1309 {
   1310 	FLAC__Metadata_Chain *chain = (FLAC__Metadata_Chain*)client_data;
   1311 	(void)decoder, (void)status;
   1312 	chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
   1313 }
   1314 
   1315 static FLAC__bool chain_read_ogg_cb_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb)
   1316 {
   1317 	FLAC__StreamDecoder *decoder;
   1318 
   1319 	FLAC__ASSERT(0 != chain);
   1320 
   1321 	/* we assume we're already at the beginning of the file */
   1322 
   1323 	chain->handle = handle;
   1324 	chain->read_cb = read_cb;
   1325 	if(0 == (decoder = FLAC__stream_decoder_new())) {
   1326 		chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1327 		return false;
   1328 	}
   1329 	FLAC__stream_decoder_set_metadata_respond_all(decoder);
   1330 	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) {
   1331 		FLAC__stream_decoder_delete(decoder);
   1332 		chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
   1333 		return false;
   1334 	}
   1335 
   1336 	chain->first_offset = 0; /*@@@ wrong; will need to be set correctly to implement metadata writing for Ogg FLAC */
   1337 
   1338 	if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder))
   1339 		chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR; /*@@@ maybe needs better error code */
   1340 	if(chain->status != FLAC__METADATA_CHAIN_STATUS_OK) {
   1341 		FLAC__stream_decoder_delete(decoder);
   1342 		return false;
   1343 	}
   1344 
   1345 	FLAC__stream_decoder_delete(decoder);
   1346 
   1347 	chain->last_offset = 0; /*@@@ wrong; will need to be set correctly to implement metadata writing for Ogg FLAC */
   1348 
   1349 	chain->initial_length = chain_calculate_length_(chain);
   1350 
   1351 	return true;
   1352 }
   1353 
   1354 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)
   1355 {
   1356 	FLAC__Metadata_Node *node;
   1357 
   1358 	FLAC__ASSERT(0 != chain);
   1359 	FLAC__ASSERT(0 != chain->head);
   1360 
   1361 	if(0 != seek_cb(handle, chain->first_offset, SEEK_SET)) {
   1362 		chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1363 		return false;
   1364 	}
   1365 
   1366 	for(node = chain->head; node; node = node->next) {
   1367 		if(!write_metadata_block_header_cb_(handle, write_cb, node->data)) {
   1368 			chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
   1369 			return false;
   1370 		}
   1371 		if(!write_metadata_block_data_cb_(handle, write_cb, node->data)) {
   1372 			chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
   1373 			return false;
   1374 		}
   1375 	}
   1376 
   1377 	/*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
   1378 
   1379 	chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
   1380 	return true;
   1381 }
   1382 
   1383 static FLAC__bool chain_rewrite_metadata_in_place_(FLAC__Metadata_Chain *chain)
   1384 {
   1385 	FILE *file;
   1386 	FLAC__bool ret;
   1387 
   1388 	FLAC__ASSERT(0 != chain->filename);
   1389 
   1390 	if(0 == (file = flac_fopen(chain->filename, "r+b"))) {
   1391 		chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
   1392 		return false;
   1393 	}
   1394 
   1395 	/* chain_rewrite_metadata_in_place_cb_() sets chain->status for us */
   1396 	ret = chain_rewrite_metadata_in_place_cb_(chain, (FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, fseek_wrapper_);
   1397 
   1398 	fclose(file);
   1399 
   1400 	return ret;
   1401 }
   1402 
   1403 static FLAC__bool chain_rewrite_file_(FLAC__Metadata_Chain *chain, const char *tempfile_path_prefix)
   1404 {
   1405 	FILE *f, *tempfile = NULL;
   1406 	char *tempfilename;
   1407 	FLAC__Metadata_SimpleIteratorStatus status;
   1408 	const FLAC__Metadata_Node *node;
   1409 
   1410 	FLAC__ASSERT(0 != chain);
   1411 	FLAC__ASSERT(0 != chain->filename);
   1412 	FLAC__ASSERT(0 != chain->head);
   1413 
   1414 	/* copy the file prefix (data up to first metadata block */
   1415 	if(0 == (f = flac_fopen(chain->filename, "rb"))) {
   1416 		chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
   1417 		return false;
   1418 	}
   1419 	if(!open_tempfile_(chain->filename, tempfile_path_prefix, &tempfile, &tempfilename, &status)) {
   1420 		chain->status = get_equivalent_status_(status);
   1421 		goto err;
   1422 	}
   1423 	if(!copy_n_bytes_from_file_(f, tempfile, chain->first_offset, &status)) {
   1424 		chain->status = get_equivalent_status_(status);
   1425 		goto err;
   1426 	}
   1427 
   1428 	/* write the metadata */
   1429 	for(node = chain->head; node; node = node->next) {
   1430 		if(!write_metadata_block_header_(tempfile, &status, node->data)) {
   1431 			chain->status = get_equivalent_status_(status);
   1432 			goto err;
   1433 		}
   1434 		if(!write_metadata_block_data_(tempfile, &status, node->data)) {
   1435 			chain->status = get_equivalent_status_(status);
   1436 			goto err;
   1437 		}
   1438 	}
   1439 	/*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
   1440 
   1441 	/* copy the file postfix (everything after the metadata) */
   1442 	if(0 != fseeko(f, chain->last_offset, SEEK_SET)) {
   1443 		chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1444 		goto err;
   1445 	}
   1446 	if(!copy_remaining_bytes_from_file_(f, tempfile, &status)) {
   1447 		chain->status = get_equivalent_status_(status);
   1448 		goto err;
   1449 	}
   1450 
   1451 	/* move the tempfile on top of the original */
   1452 	(void)fclose(f);
   1453 	if(!transport_tempfile_(chain->filename, &tempfile, &tempfilename, &status))
   1454 		return false;
   1455 
   1456 	return true;
   1457 
   1458 err:
   1459 	(void)fclose(f);
   1460 	cleanup_tempfile_(&tempfile, &tempfilename);
   1461 	return false;
   1462 }
   1463 
   1464 /* assumes 'handle' is already at beginning of file */
   1465 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)
   1466 {
   1467 	FLAC__Metadata_SimpleIteratorStatus status;
   1468 	const FLAC__Metadata_Node *node;
   1469 
   1470 	FLAC__ASSERT(0 != chain);
   1471 	FLAC__ASSERT(0 == chain->filename);
   1472 	FLAC__ASSERT(0 != chain->head);
   1473 
   1474 	/* copy the file prefix (data up to first metadata block */
   1475 	if(!copy_n_bytes_from_file_cb_(handle, read_cb, temp_handle, temp_write_cb, chain->first_offset, &status)) {
   1476 		chain->status = get_equivalent_status_(status);
   1477 		return false;
   1478 	}
   1479 
   1480 	/* write the metadata */
   1481 	for(node = chain->head; node; node = node->next) {
   1482 		if(!write_metadata_block_header_cb_(temp_handle, temp_write_cb, node->data)) {
   1483 			chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
   1484 			return false;
   1485 		}
   1486 		if(!write_metadata_block_data_cb_(temp_handle, temp_write_cb, node->data)) {
   1487 			chain->status = FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
   1488 			return false;
   1489 		}
   1490 	}
   1491 	/*FLAC__ASSERT(fflush(), ftello() == chain->last_offset);*/
   1492 
   1493 	/* copy the file postfix (everything after the metadata) */
   1494 	if(0 != seek_cb(handle, chain->last_offset, SEEK_SET)) {
   1495 		chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1496 		return false;
   1497 	}
   1498 	if(!copy_remaining_bytes_from_file_cb_(handle, read_cb, eof_cb, temp_handle, temp_write_cb, &status)) {
   1499 		chain->status = get_equivalent_status_(status);
   1500 		return false;
   1501 	}
   1502 
   1503 	return true;
   1504 }
   1505 
   1506 FLAC_API FLAC__Metadata_Chain *FLAC__metadata_chain_new(void)
   1507 {
   1508 	FLAC__Metadata_Chain *chain = calloc(1, sizeof(FLAC__Metadata_Chain));
   1509 
   1510 	if(0 != chain)
   1511 		chain_init_(chain);
   1512 
   1513 	return chain;
   1514 }
   1515 
   1516 FLAC_API void FLAC__metadata_chain_delete(FLAC__Metadata_Chain *chain)
   1517 {
   1518 	FLAC__ASSERT(0 != chain);
   1519 
   1520 	chain_clear_(chain);
   1521 
   1522 	free(chain);
   1523 }
   1524 
   1525 FLAC_API FLAC__Metadata_ChainStatus FLAC__metadata_chain_status(FLAC__Metadata_Chain *chain)
   1526 {
   1527 	FLAC__Metadata_ChainStatus status;
   1528 
   1529 	FLAC__ASSERT(0 != chain);
   1530 
   1531 	status = chain->status;
   1532 	chain->status = FLAC__METADATA_CHAIN_STATUS_OK;
   1533 	return status;
   1534 }
   1535 
   1536 static FLAC__bool chain_read_(FLAC__Metadata_Chain *chain, const char *filename, FLAC__bool is_ogg)
   1537 {
   1538 	FILE *file;
   1539 	FLAC__bool ret;
   1540 
   1541 	FLAC__ASSERT(0 != chain);
   1542 	FLAC__ASSERT(0 != filename);
   1543 
   1544 	chain_clear_(chain);
   1545 
   1546 	if(0 == (chain->filename = strdup(filename))) {
   1547 		chain->status = FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   1548 		return false;
   1549 	}
   1550 
   1551 	chain->is_ogg = is_ogg;
   1552 
   1553 	if(0 == (file = flac_fopen(filename, "rb"))) {
   1554 		chain->status = FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
   1555 		return false;
   1556 	}
   1557 
   1558 	/* the function also sets chain->status for us */
   1559 	ret = is_ogg?
   1560 		chain_read_ogg_cb_(chain, file, (FLAC__IOCallback_Read)fread) :
   1561 		chain_read_cb_(chain, file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, ftell_wrapper_)
   1562 	;
   1563 
   1564 	fclose(file);
   1565 
   1566 	return ret;
   1567 }
   1568 
   1569 FLAC_API FLAC__bool FLAC__metadata_chain_read(FLAC__Metadata_Chain *chain, const char *filename)
   1570 {
   1571 	return chain_read_(chain, filename, /*is_ogg=*/false);
   1572 }
   1573 
   1574 /*@@@@add to tests*/
   1575 FLAC_API FLAC__bool FLAC__metadata_chain_read_ogg(FLAC__Metadata_Chain *chain, const char *filename)
   1576 {
   1577 	return chain_read_(chain, filename, /*is_ogg=*/true);
   1578 }
   1579 
   1580 static FLAC__bool chain_read_with_callbacks_(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks, FLAC__bool is_ogg)
   1581 {
   1582 	FLAC__bool ret;
   1583 
   1584 	FLAC__ASSERT(0 != chain);
   1585 
   1586 	chain_clear_(chain);
   1587 
   1588 	if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.tell) {
   1589 		chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
   1590 		return false;
   1591 	}
   1592 
   1593 	chain->is_ogg = is_ogg;
   1594 
   1595 	/* rewind */
   1596 	if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
   1597 		chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1598 		return false;
   1599 	}
   1600 
   1601 	/* the function also sets chain->status for us */
   1602 	ret = is_ogg?
   1603 		chain_read_ogg_cb_(chain, handle, callbacks.read) :
   1604 		chain_read_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.tell)
   1605 	;
   1606 
   1607 	return ret;
   1608 }
   1609 
   1610 FLAC_API FLAC__bool FLAC__metadata_chain_read_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
   1611 {
   1612 	return chain_read_with_callbacks_(chain, handle, callbacks, /*is_ogg=*/false);
   1613 }
   1614 
   1615 /*@@@@add to tests*/
   1616 FLAC_API FLAC__bool FLAC__metadata_chain_read_ogg_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
   1617 {
   1618 	return chain_read_with_callbacks_(chain, handle, callbacks, /*is_ogg=*/true);
   1619 }
   1620 
   1621 typedef enum {
   1622 	LBS_NONE = 0,
   1623 	LBS_SIZE_CHANGED,
   1624 	LBS_BLOCK_ADDED,
   1625 	LBS_BLOCK_REMOVED
   1626 } LastBlockState;
   1627 
   1628 FLAC_API FLAC__bool FLAC__metadata_chain_check_if_tempfile_needed(FLAC__Metadata_Chain *chain, FLAC__bool use_padding)
   1629 {
   1630 	/* This does all the same checks that are in chain_prepare_for_write_()
   1631 	 * but doesn't actually alter the chain.  Make sure to update the logic
   1632 	 * here if chain_prepare_for_write_() changes.
   1633 	 */
   1634 	FLAC__off_t current_length;
   1635 	LastBlockState lbs_state = LBS_NONE;
   1636 	unsigned lbs_size = 0;
   1637 
   1638 	FLAC__ASSERT(0 != chain);
   1639 
   1640 	current_length = chain_calculate_length_(chain);
   1641 
   1642 	if(use_padding) {
   1643 		const FLAC__Metadata_Node * const node = chain->tail;
   1644 		/* if the metadata shrank and the last block is padding, we just extend the last padding block */
   1645 		if(current_length < chain->initial_length && node->data->type == FLAC__METADATA_TYPE_PADDING) {
   1646 			lbs_state = LBS_SIZE_CHANGED;
   1647 			lbs_size = node->data->length + (chain->initial_length - current_length);
   1648 		}
   1649 		/* if the metadata shrank more than 4 bytes then there's room to add another padding block */
   1650 		else if(current_length + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH <= chain->initial_length) {
   1651 			lbs_state = LBS_BLOCK_ADDED;
   1652 			lbs_size = chain->initial_length - (current_length + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH);
   1653 		}
   1654 		/* 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 */
   1655 		else if(current_length > chain->initial_length) {
   1656 			const FLAC__off_t delta = current_length - chain->initial_length;
   1657 			if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
   1658 				/* if the delta is exactly the size of the last padding block, remove the padding block */
   1659 				if((FLAC__off_t)node->data->length + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH == delta) {
   1660 					lbs_state = LBS_BLOCK_REMOVED;
   1661 					lbs_size = 0;
   1662 				}
   1663 				/* if there is at least 'delta' bytes of padding, trim the padding down */
   1664 				else if((FLAC__off_t)node->data->length >= delta) {
   1665 					lbs_state = LBS_SIZE_CHANGED;
   1666 					lbs_size = node->data->length - delta;
   1667 				}
   1668 			}
   1669 		}
   1670 	}
   1671 
   1672 	current_length = 0;
   1673 	/* check sizes of all metadata blocks; reduce padding size if necessary */
   1674 	{
   1675 		const FLAC__Metadata_Node *node;
   1676 		for(node = chain->head; node; node = node->next) {
   1677 			unsigned block_len = node->data->length;
   1678 			if(node == chain->tail) {
   1679 				if(lbs_state == LBS_BLOCK_REMOVED)
   1680 					continue;
   1681 				else if(lbs_state == LBS_SIZE_CHANGED)
   1682 					block_len = lbs_size;
   1683 			}
   1684 			if(block_len >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN)) {
   1685 				if(node->data->type == FLAC__METADATA_TYPE_PADDING)
   1686 					block_len = (1u << FLAC__STREAM_METADATA_LENGTH_LEN) - 1;
   1687 				else
   1688 					return false /* the return value doesn't matter */;
   1689 			}
   1690 			current_length += (FLAC__STREAM_METADATA_HEADER_LENGTH + block_len);
   1691 		}
   1692 
   1693 		if(lbs_state == LBS_BLOCK_ADDED) {
   1694 			/* test added padding block */
   1695 			unsigned block_len = lbs_size;
   1696 			if(block_len >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN))
   1697 				block_len = (1u << FLAC__STREAM_METADATA_LENGTH_LEN) - 1;
   1698 			current_length += (FLAC__STREAM_METADATA_HEADER_LENGTH + block_len);
   1699 		}
   1700 	}
   1701 
   1702 	return (current_length != chain->initial_length);
   1703 }
   1704 
   1705 FLAC_API FLAC__bool FLAC__metadata_chain_write(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__bool preserve_file_stats)
   1706 {
   1707 	struct flac_stat_s stats;
   1708 	const char *tempfile_path_prefix = 0;
   1709 	FLAC__off_t current_length;
   1710 
   1711 	FLAC__ASSERT(0 != chain);
   1712 
   1713 	if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
   1714 		chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
   1715 		return false;
   1716 	}
   1717 
   1718 	if (0 == chain->filename) {
   1719 		chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
   1720 		return false;
   1721 	}
   1722 
   1723 	current_length = chain_prepare_for_write_(chain, use_padding);
   1724 
   1725 	/* a return value of 0 means there was an error; chain->status is already set */
   1726 	if (0 == current_length)
   1727 		return false;
   1728 
   1729 	if(preserve_file_stats)
   1730 		get_file_stats_(chain->filename, &stats);
   1731 
   1732 	if(current_length == chain->initial_length) {
   1733 		if(!chain_rewrite_metadata_in_place_(chain))
   1734 			return false;
   1735 	}
   1736 	else {
   1737 		if(!chain_rewrite_file_(chain, tempfile_path_prefix))
   1738 			return false;
   1739 
   1740 		/* recompute lengths and offsets */
   1741 		{
   1742 			const FLAC__Metadata_Node *node;
   1743 			chain->initial_length = current_length;
   1744 			chain->last_offset = chain->first_offset;
   1745 			for(node = chain->head; node; node = node->next)
   1746 				chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
   1747 		}
   1748 	}
   1749 
   1750 	if(preserve_file_stats)
   1751 		set_file_stats_(chain->filename, &stats);
   1752 
   1753 	return true;
   1754 }
   1755 
   1756 FLAC_API FLAC__bool FLAC__metadata_chain_write_with_callbacks(FLAC__Metadata_Chain *chain, FLAC__bool use_padding, FLAC__IOHandle handle, FLAC__IOCallbacks callbacks)
   1757 {
   1758 	FLAC__off_t current_length;
   1759 
   1760 	FLAC__ASSERT(0 != chain);
   1761 
   1762 	if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
   1763 		chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
   1764 		return false;
   1765 	}
   1766 
   1767 	if (0 != chain->filename) {
   1768 		chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
   1769 		return false;
   1770 	}
   1771 
   1772 	if (0 == callbacks.write || 0 == callbacks.seek) {
   1773 		chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
   1774 		return false;
   1775 	}
   1776 
   1777 	if (FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
   1778 		chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
   1779 		return false;
   1780 	}
   1781 
   1782 	current_length = chain_prepare_for_write_(chain, use_padding);
   1783 
   1784 	/* a return value of 0 means there was an error; chain->status is already set */
   1785 	if (0 == current_length)
   1786 		return false;
   1787 
   1788 	FLAC__ASSERT(current_length == chain->initial_length);
   1789 
   1790 	return chain_rewrite_metadata_in_place_cb_(chain, handle, callbacks.write, callbacks.seek);
   1791 }
   1792 
   1793 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)
   1794 {
   1795 	FLAC__off_t current_length;
   1796 
   1797 	FLAC__ASSERT(0 != chain);
   1798 
   1799 	if (chain->is_ogg) { /* cannot write back to Ogg FLAC yet */
   1800 		chain->status = FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
   1801 		return false;
   1802 	}
   1803 
   1804 	if (0 != chain->filename) {
   1805 		chain->status = FLAC__METADATA_CHAIN_STATUS_READ_WRITE_MISMATCH;
   1806 		return false;
   1807 	}
   1808 
   1809 	if (0 == callbacks.read || 0 == callbacks.seek || 0 == callbacks.eof) {
   1810 		chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
   1811 		return false;
   1812 	}
   1813 	if (0 == temp_callbacks.write) {
   1814 		chain->status = FLAC__METADATA_CHAIN_STATUS_INVALID_CALLBACKS;
   1815 		return false;
   1816 	}
   1817 
   1818 	if (!FLAC__metadata_chain_check_if_tempfile_needed(chain, use_padding)) {
   1819 		chain->status = FLAC__METADATA_CHAIN_STATUS_WRONG_WRITE_CALL;
   1820 		return false;
   1821 	}
   1822 
   1823 	current_length = chain_prepare_for_write_(chain, use_padding);
   1824 
   1825 	/* a return value of 0 means there was an error; chain->status is already set */
   1826 	if (0 == current_length)
   1827 		return false;
   1828 
   1829 	FLAC__ASSERT(current_length != chain->initial_length);
   1830 
   1831 	/* rewind */
   1832 	if(0 != callbacks.seek(handle, 0, SEEK_SET)) {
   1833 		chain->status = FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   1834 		return false;
   1835 	}
   1836 
   1837 	if(!chain_rewrite_file_cb_(chain, handle, callbacks.read, callbacks.seek, callbacks.eof, temp_handle, temp_callbacks.write))
   1838 		return false;
   1839 
   1840 	/* recompute lengths and offsets */
   1841 	{
   1842 		const FLAC__Metadata_Node *node;
   1843 		chain->initial_length = current_length;
   1844 		chain->last_offset = chain->first_offset;
   1845 		for(node = chain->head; node; node = node->next)
   1846 			chain->last_offset += (FLAC__STREAM_METADATA_HEADER_LENGTH + node->data->length);
   1847 	}
   1848 
   1849 	return true;
   1850 }
   1851 
   1852 FLAC_API void FLAC__metadata_chain_merge_padding(FLAC__Metadata_Chain *chain)
   1853 {
   1854 	FLAC__Metadata_Node *node;
   1855 
   1856 	FLAC__ASSERT(0 != chain);
   1857 
   1858 	for(node = chain->head; node; ) {
   1859 		if(!chain_merge_adjacent_padding_(chain, node))
   1860 			node = node->next;
   1861 	}
   1862 }
   1863 
   1864 FLAC_API void FLAC__metadata_chain_sort_padding(FLAC__Metadata_Chain *chain)
   1865 {
   1866 	FLAC__Metadata_Node *node, *save;
   1867 	unsigned i;
   1868 
   1869 	FLAC__ASSERT(0 != chain);
   1870 
   1871 	/*
   1872 	 * Don't try and be too smart... this simple algo is good enough for
   1873 	 * the small number of nodes that we deal with.
   1874 	 */
   1875 	for(i = 0, node = chain->head; i < chain->nodes; i++) {
   1876 		if(node->data->type == FLAC__METADATA_TYPE_PADDING) {
   1877 			save = node->next;
   1878 			chain_remove_node_(chain, node);
   1879 			chain_append_node_(chain, node);
   1880 			node = save;
   1881 		}
   1882 		else {
   1883 			node = node->next;
   1884 		}
   1885 	}
   1886 
   1887 	FLAC__metadata_chain_merge_padding(chain);
   1888 }
   1889 
   1890 
   1891 FLAC_API FLAC__Metadata_Iterator *FLAC__metadata_iterator_new(void)
   1892 {
   1893 	FLAC__Metadata_Iterator *iterator = calloc(1, sizeof(FLAC__Metadata_Iterator));
   1894 
   1895 	/* calloc() implies:
   1896 		iterator->current = 0;
   1897 		iterator->chain = 0;
   1898 	*/
   1899 
   1900 	return iterator;
   1901 }
   1902 
   1903 FLAC_API void FLAC__metadata_iterator_delete(FLAC__Metadata_Iterator *iterator)
   1904 {
   1905 	FLAC__ASSERT(0 != iterator);
   1906 
   1907 	free(iterator);
   1908 }
   1909 
   1910 FLAC_API void FLAC__metadata_iterator_init(FLAC__Metadata_Iterator *iterator, FLAC__Metadata_Chain *chain)
   1911 {
   1912 	FLAC__ASSERT(0 != iterator);
   1913 	FLAC__ASSERT(0 != chain);
   1914 	FLAC__ASSERT(0 != chain->head);
   1915 
   1916 	iterator->chain = chain;
   1917 	iterator->current = chain->head;
   1918 }
   1919 
   1920 FLAC_API FLAC__bool FLAC__metadata_iterator_next(FLAC__Metadata_Iterator *iterator)
   1921 {
   1922 	FLAC__ASSERT(0 != iterator);
   1923 
   1924 	if(0 == iterator->current || 0 == iterator->current->next)
   1925 		return false;
   1926 
   1927 	iterator->current = iterator->current->next;
   1928 	return true;
   1929 }
   1930 
   1931 FLAC_API FLAC__bool FLAC__metadata_iterator_prev(FLAC__Metadata_Iterator *iterator)
   1932 {
   1933 	FLAC__ASSERT(0 != iterator);
   1934 
   1935 	if(0 == iterator->current || 0 == iterator->current->prev)
   1936 		return false;
   1937 
   1938 	iterator->current = iterator->current->prev;
   1939 	return true;
   1940 }
   1941 
   1942 FLAC_API FLAC__MetadataType FLAC__metadata_iterator_get_block_type(const FLAC__Metadata_Iterator *iterator)
   1943 {
   1944 	FLAC__ASSERT(0 != iterator);
   1945 	FLAC__ASSERT(0 != iterator->current);
   1946 	FLAC__ASSERT(0 != iterator->current->data);
   1947 
   1948 	return iterator->current->data->type;
   1949 }
   1950 
   1951 FLAC_API FLAC__StreamMetadata *FLAC__metadata_iterator_get_block(FLAC__Metadata_Iterator *iterator)
   1952 {
   1953 	FLAC__ASSERT(0 != iterator);
   1954 	FLAC__ASSERT(0 != iterator->current);
   1955 
   1956 	return iterator->current->data;
   1957 }
   1958 
   1959 FLAC_API FLAC__bool FLAC__metadata_iterator_set_block(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
   1960 {
   1961 	FLAC__ASSERT(0 != iterator);
   1962 	FLAC__ASSERT(0 != block);
   1963 	return FLAC__metadata_iterator_delete_block(iterator, false) && FLAC__metadata_iterator_insert_block_after(iterator, block);
   1964 }
   1965 
   1966 FLAC_API FLAC__bool FLAC__metadata_iterator_delete_block(FLAC__Metadata_Iterator *iterator, FLAC__bool replace_with_padding)
   1967 {
   1968 	FLAC__Metadata_Node *save;
   1969 
   1970 	FLAC__ASSERT(0 != iterator);
   1971 	FLAC__ASSERT(0 != iterator->current);
   1972 
   1973 	if(0 == iterator->current->prev) {
   1974 		FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
   1975 		return false;
   1976 	}
   1977 
   1978 	save = iterator->current->prev;
   1979 
   1980 	if(replace_with_padding) {
   1981 		FLAC__metadata_object_delete_data(iterator->current->data);
   1982 		iterator->current->data->type = FLAC__METADATA_TYPE_PADDING;
   1983 	}
   1984 	else {
   1985 		chain_delete_node_(iterator->chain, iterator->current);
   1986 	}
   1987 
   1988 	iterator->current = save;
   1989 	return true;
   1990 }
   1991 
   1992 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_before(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
   1993 {
   1994 	FLAC__Metadata_Node *node;
   1995 
   1996 	FLAC__ASSERT(0 != iterator);
   1997 	FLAC__ASSERT(0 != iterator->current);
   1998 	FLAC__ASSERT(0 != block);
   1999 
   2000 	if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
   2001 		return false;
   2002 
   2003 	if(0 == iterator->current->prev) {
   2004 		FLAC__ASSERT(iterator->current->data->type == FLAC__METADATA_TYPE_STREAMINFO);
   2005 		return false;
   2006 	}
   2007 
   2008 	if(0 == (node = node_new_()))
   2009 		return false;
   2010 
   2011 	node->data = block;
   2012 	iterator_insert_node_(iterator, node);
   2013 	iterator->current = node;
   2014 	return true;
   2015 }
   2016 
   2017 FLAC_API FLAC__bool FLAC__metadata_iterator_insert_block_after(FLAC__Metadata_Iterator *iterator, FLAC__StreamMetadata *block)
   2018 {
   2019 	FLAC__Metadata_Node *node;
   2020 
   2021 	FLAC__ASSERT(0 != iterator);
   2022 	FLAC__ASSERT(0 != iterator->current);
   2023 	FLAC__ASSERT(0 != block);
   2024 
   2025 	if(block->type == FLAC__METADATA_TYPE_STREAMINFO)
   2026 		return false;
   2027 
   2028 	if(0 == (node = node_new_()))
   2029 		return false;
   2030 
   2031 	node->data = block;
   2032 	iterator_insert_node_after_(iterator, node);
   2033 	iterator->current = node;
   2034 	return true;
   2035 }
   2036 
   2037 
   2038 /****************************************************************************
   2039  *
   2040  * Local function definitions
   2041  *
   2042  ***************************************************************************/
   2043 
   2044 void pack_uint32_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
   2045 {
   2046 	unsigned i;
   2047 
   2048 	b += bytes;
   2049 
   2050 	for(i = 0; i < bytes; i++) {
   2051 		*(--b) = (FLAC__byte)(val & 0xff);
   2052 		val >>= 8;
   2053 	}
   2054 }
   2055 
   2056 void pack_uint32_little_endian_(FLAC__uint32 val, FLAC__byte *b, unsigned bytes)
   2057 {
   2058 	unsigned i;
   2059 
   2060 	for(i = 0; i < bytes; i++) {
   2061 		*(b++) = (FLAC__byte)(val & 0xff);
   2062 		val >>= 8;
   2063 	}
   2064 }
   2065 
   2066 void pack_uint64_(FLAC__uint64 val, FLAC__byte *b, unsigned bytes)
   2067 {
   2068 	unsigned i;
   2069 
   2070 	b += bytes;
   2071 
   2072 	for(i = 0; i < bytes; i++) {
   2073 		*(--b) = (FLAC__byte)(val & 0xff);
   2074 		val >>= 8;
   2075 	}
   2076 }
   2077 
   2078 FLAC__uint32 unpack_uint32_(FLAC__byte *b, unsigned bytes)
   2079 {
   2080 	FLAC__uint32 ret = 0;
   2081 	unsigned i;
   2082 
   2083 	for(i = 0; i < bytes; i++)
   2084 		ret = (ret << 8) | (FLAC__uint32)(*b++);
   2085 
   2086 	return ret;
   2087 }
   2088 
   2089 FLAC__uint32 unpack_uint32_little_endian_(FLAC__byte *b, unsigned bytes)
   2090 {
   2091 	FLAC__uint32 ret = 0;
   2092 	unsigned i;
   2093 
   2094 	b += bytes;
   2095 
   2096 	for(i = 0; i < bytes; i++)
   2097 		ret = (ret << 8) | (FLAC__uint32)(*--b);
   2098 
   2099 	return ret;
   2100 }
   2101 
   2102 FLAC__uint64 unpack_uint64_(FLAC__byte *b, unsigned bytes)
   2103 {
   2104 	FLAC__uint64 ret = 0;
   2105 	unsigned i;
   2106 
   2107 	for(i = 0; i < bytes; i++)
   2108 		ret = (ret << 8) | (FLAC__uint64)(*b++);
   2109 
   2110 	return ret;
   2111 }
   2112 
   2113 FLAC__bool read_metadata_block_header_(FLAC__Metadata_SimpleIterator *iterator)
   2114 {
   2115 	FLAC__ASSERT(0 != iterator);
   2116 	FLAC__ASSERT(0 != iterator->file);
   2117 
   2118 	if(!read_metadata_block_header_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, &iterator->is_last, &iterator->type, &iterator->length)) {
   2119 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2120 		return false;
   2121 	}
   2122 
   2123 	return true;
   2124 }
   2125 
   2126 FLAC__bool read_metadata_block_data_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block)
   2127 {
   2128 	FLAC__ASSERT(0 != iterator);
   2129 	FLAC__ASSERT(0 != iterator->file);
   2130 
   2131 	iterator->status = read_metadata_block_data_cb_((FLAC__IOHandle)iterator->file, (FLAC__IOCallback_Read)fread, fseek_wrapper_, block);
   2132 
   2133 	return (iterator->status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK);
   2134 }
   2135 
   2136 FLAC__bool read_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__bool *is_last, FLAC__MetadataType *type, unsigned *length)
   2137 {
   2138 	FLAC__byte raw_header[FLAC__STREAM_METADATA_HEADER_LENGTH];
   2139 
   2140 	if(read_cb(raw_header, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
   2141 		return false;
   2142 
   2143 	*is_last = raw_header[0] & 0x80? true : false;
   2144 	*type = (FLAC__MetadataType)(raw_header[0] & 0x7f);
   2145 	*length = unpack_uint32_(raw_header + 1, 3);
   2146 
   2147 	/* Note that we don't check:
   2148 	 *    if(iterator->type >= FLAC__METADATA_TYPE_UNDEFINED)
   2149 	 * we just will read in an opaque block
   2150 	 */
   2151 
   2152 	return true;
   2153 }
   2154 
   2155 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata *block)
   2156 {
   2157 	switch(block->type) {
   2158 		case FLAC__METADATA_TYPE_STREAMINFO:
   2159 			return read_metadata_block_data_streaminfo_cb_(handle, read_cb, &block->data.stream_info);
   2160 		case FLAC__METADATA_TYPE_PADDING:
   2161 			return read_metadata_block_data_padding_cb_(handle, seek_cb, &block->data.padding, block->length);
   2162 		case FLAC__METADATA_TYPE_APPLICATION:
   2163 			return read_metadata_block_data_application_cb_(handle, read_cb, &block->data.application, block->length);
   2164 		case FLAC__METADATA_TYPE_SEEKTABLE:
   2165 			return read_metadata_block_data_seektable_cb_(handle, read_cb, &block->data.seek_table, block->length);
   2166 		case FLAC__METADATA_TYPE_VORBIS_COMMENT:
   2167 			return read_metadata_block_data_vorbis_comment_cb_(handle, read_cb, seek_cb, &block->data.vorbis_comment, block->length);
   2168 		case FLAC__METADATA_TYPE_CUESHEET:
   2169 			return read_metadata_block_data_cuesheet_cb_(handle, read_cb, &block->data.cue_sheet);
   2170 		case FLAC__METADATA_TYPE_PICTURE:
   2171 			return read_metadata_block_data_picture_cb_(handle, read_cb, &block->data.picture);
   2172 		default:
   2173 			return read_metadata_block_data_unknown_cb_(handle, read_cb, &block->data.unknown, block->length);
   2174 	}
   2175 }
   2176 
   2177 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_StreamInfo *block)
   2178 {
   2179 	FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH], *b;
   2180 
   2181 	if(read_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
   2182 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2183 
   2184 	b = buffer;
   2185 
   2186 	/* we are using hardcoded numbers for simplicity but we should
   2187 	 * probably eventually write a bit-level unpacker and use the
   2188 	 * _STREAMINFO_ constants.
   2189 	 */
   2190 	block->min_blocksize = unpack_uint32_(b, 2); b += 2;
   2191 	block->max_blocksize = unpack_uint32_(b, 2); b += 2;
   2192 	block->min_framesize = unpack_uint32_(b, 3); b += 3;
   2193 	block->max_framesize = unpack_uint32_(b, 3); b += 3;
   2194 	block->sample_rate = (unpack_uint32_(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
   2195 	block->channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
   2196 	block->bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 4) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
   2197 	block->total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64_(b+4, 4);
   2198 	memcpy(block->md5sum, b+8, 16);
   2199 
   2200 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2201 }
   2202 
   2203 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_Padding *block, unsigned block_length)
   2204 {
   2205 	(void)block; /* nothing to do; we don't care about reading the padding bytes */
   2206 
   2207 	if(0 != seek_cb(handle, block_length, SEEK_CUR))
   2208 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2209 
   2210 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2211 }
   2212 
   2213 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Application *block, unsigned block_length)
   2214 {
   2215 	const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
   2216 
   2217 	if(read_cb(block->id, 1, id_bytes, handle) != id_bytes)
   2218 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2219 
   2220 	if(block_length < id_bytes)
   2221 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2222 
   2223 	block_length -= id_bytes;
   2224 
   2225 	if(block_length == 0) {
   2226 		block->data = 0;
   2227 	}
   2228 	else {
   2229 		if(0 == (block->data = malloc(block_length)))
   2230 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2231 
   2232 		if(read_cb(block->data, 1, block_length, handle) != block_length)
   2233 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2234 	}
   2235 
   2236 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2237 }
   2238 
   2239 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_SeekTable *block, unsigned block_length)
   2240 {
   2241 	unsigned i;
   2242 	FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
   2243 
   2244 	FLAC__ASSERT(block_length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH == 0);
   2245 
   2246 	block->num_points = block_length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
   2247 
   2248 	if(block->num_points == 0)
   2249 		block->points = 0;
   2250 	else if(0 == (block->points = safe_malloc_mul_2op_p(block->num_points, /*times*/sizeof(FLAC__StreamMetadata_SeekPoint))))
   2251 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2252 
   2253 	for(i = 0; i < block->num_points; i++) {
   2254 		if(read_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
   2255 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2256 		/* some MAGIC NUMBERs here */
   2257 		block->points[i].sample_number = unpack_uint64_(buffer, 8);
   2258 		block->points[i].stream_offset = unpack_uint64_(buffer+8, 8);
   2259 		block->points[i].frame_samples = unpack_uint32_(buffer+16, 2);
   2260 	}
   2261 
   2262 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2263 }
   2264 
   2265 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_entry_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_VorbisComment_Entry *entry, unsigned max_length)
   2266 {
   2267 	const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
   2268 	FLAC__byte buffer[4]; /* magic number is asserted below */
   2269 
   2270 	FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8 == sizeof(buffer));
   2271 
   2272 	if(max_length < entry_length_len)
   2273 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA;
   2274 
   2275 	max_length -= entry_length_len;
   2276 	if(read_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
   2277 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2278 	entry->length = unpack_uint32_little_endian_(buffer, entry_length_len);
   2279 	if(max_length < entry->length) {
   2280 		entry->length = 0;
   2281 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA;
   2282 	} else max_length -= entry->length;
   2283 
   2284 	if(0 != entry->entry)
   2285 		free(entry->entry);
   2286 
   2287 	if(entry->length == 0) {
   2288 		entry->entry = 0;
   2289 	}
   2290 	else {
   2291 		if(0 == (entry->entry = safe_malloc_add_2op_(entry->length, /*+*/1)))
   2292 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2293 
   2294 		if(read_cb(entry->entry, 1, entry->length, handle) != entry->length)
   2295 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2296 
   2297 		entry->entry[entry->length] = '\0';
   2298 	}
   2299 
   2300 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2301 }
   2302 
   2303 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb, FLAC__StreamMetadata_VorbisComment *block, unsigned block_length)
   2304 {
   2305 	unsigned i;
   2306 	FLAC__Metadata_SimpleIteratorStatus status;
   2307 	const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
   2308 	FLAC__byte buffer[4]; /* magic number is asserted below */
   2309 
   2310 	FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8 == sizeof(buffer));
   2311 
   2312 	status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, &(block->vendor_string), block_length);
   2313 	if(block_length >= 4)
   2314 		block_length -= 4;
   2315 	if(status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA)
   2316 		goto skip;
   2317 	else if(status != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK)
   2318 		return status;
   2319 	block_length -= block->vendor_string.length;
   2320 
   2321 	if(block_length < num_comments_len) goto skip; else block_length -= num_comments_len;
   2322 	if(read_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
   2323 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2324 	block->num_comments = unpack_uint32_little_endian_(buffer, num_comments_len);
   2325 
   2326 	if(block->num_comments == 0) {
   2327 		block->comments = 0;
   2328 	}
   2329 	else if(0 == (block->comments = calloc(block->num_comments, sizeof(FLAC__StreamMetadata_VorbisComment_Entry)))) {
   2330 		block->num_comments = 0;
   2331 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2332 	}
   2333 
   2334 	for(i = 0; i < block->num_comments; i++) {
   2335 		status = read_metadata_block_data_vorbis_comment_entry_cb_(handle, read_cb, block->comments + i, block_length);
   2336 		if(block_length >= 4) block_length -= 4;
   2337 		if(status == FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA) {
   2338 			block->num_comments = i;
   2339 			goto skip;
   2340 		}
   2341 		else if(status != FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK) return status;
   2342 		block_length -= block->comments[i].length;
   2343 	}
   2344 
   2345   skip:
   2346 	if(block_length > 0) {
   2347 		/* bad metadata */
   2348 		if(0 != seek_cb(handle, block_length, SEEK_CUR))
   2349 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2350 	}
   2351 
   2352 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2353 }
   2354 
   2355 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_track_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet_Track *track)
   2356 {
   2357 	unsigned i, len;
   2358 	FLAC__byte buffer[32]; /* asserted below that this is big enough */
   2359 
   2360 	FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
   2361 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
   2362 	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);
   2363 
   2364 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
   2365 	len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
   2366 	if(read_cb(buffer, 1, len, handle) != len)
   2367 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2368 	track->offset = unpack_uint64_(buffer, len);
   2369 
   2370 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
   2371 	len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
   2372 	if(read_cb(buffer, 1, len, handle) != len)
   2373 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2374 	track->number = (FLAC__byte)unpack_uint32_(buffer, len);
   2375 
   2376 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
   2377 	len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
   2378 	if(read_cb(track->isrc, 1, len, handle) != len)
   2379 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2380 
   2381 	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);
   2382 	len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
   2383 	if(read_cb(buffer, 1, len, handle) != len)
   2384 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2385 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN == 1);
   2386 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN == 1);
   2387 	track->type = buffer[0] >> 7;
   2388 	track->pre_emphasis = (buffer[0] >> 6) & 1;
   2389 
   2390 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
   2391 	len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
   2392 	if(read_cb(buffer, 1, len, handle) != len)
   2393 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2394 	track->num_indices = (FLAC__byte)unpack_uint32_(buffer, len);
   2395 
   2396 	if(track->num_indices == 0) {
   2397 		track->indices = 0;
   2398 	}
   2399 	else if(0 == (track->indices = calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index))))
   2400 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2401 
   2402 	for(i = 0; i < track->num_indices; i++) {
   2403 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
   2404 		len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
   2405 		if(read_cb(buffer, 1, len, handle) != len)
   2406 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2407 		track->indices[i].offset = unpack_uint64_(buffer, len);
   2408 
   2409 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
   2410 		len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
   2411 		if(read_cb(buffer, 1, len, handle) != len)
   2412 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2413 		track->indices[i].number = (FLAC__byte)unpack_uint32_(buffer, len);
   2414 
   2415 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
   2416 		len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
   2417 		if(read_cb(buffer, 1, len, handle) != len)
   2418 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2419 	}
   2420 
   2421 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2422 }
   2423 
   2424 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_CueSheet *block)
   2425 {
   2426 	unsigned i, len;
   2427 	FLAC__Metadata_SimpleIteratorStatus status;
   2428 	FLAC__byte buffer[1024]; /* MSVC needs a constant expression so we put a magic number and assert */
   2429 
   2430 	FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN)/8 <= sizeof(buffer));
   2431 	FLAC__ASSERT(sizeof(FLAC__uint64) <= sizeof(buffer));
   2432 
   2433 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
   2434 	len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
   2435 	if(read_cb(block->media_catalog_number, 1, len, handle) != len)
   2436 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2437 
   2438 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
   2439 	len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
   2440 	if(read_cb(buffer, 1, len, handle) != len)
   2441 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2442 	block->lead_in = unpack_uint64_(buffer, len);
   2443 
   2444 	FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
   2445 	len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
   2446 	if(read_cb(buffer, 1, len, handle) != len)
   2447 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2448 	block->is_cd = buffer[0]&0x80? true : false;
   2449 
   2450 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
   2451 	len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
   2452 	if(read_cb(buffer, 1, len, handle) != len)
   2453 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2454 	block->num_tracks = unpack_uint32_(buffer, len);
   2455 
   2456 	if(block->num_tracks == 0) {
   2457 		block->tracks = 0;
   2458 	}
   2459 	else if(0 == (block->tracks = calloc(block->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track))))
   2460 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2461 
   2462 	for(i = 0; i < block->num_tracks; i++) {
   2463 		if(FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK != (status = read_metadata_block_data_cuesheet_track_cb_(handle, read_cb, block->tracks + i)))
   2464 			return status;
   2465 	}
   2466 
   2467 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2468 }
   2469 
   2470 static 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)
   2471 {
   2472 	FLAC__byte buffer[sizeof(FLAC__uint32)];
   2473 
   2474 	FLAC__ASSERT(0 != data);
   2475 	FLAC__ASSERT(length_len%8 == 0);
   2476 
   2477 	length_len /= 8; /* convert to bytes */
   2478 
   2479 	FLAC__ASSERT(sizeof(buffer) >= length_len);
   2480 
   2481 	if(read_cb(buffer, 1, length_len, handle) != length_len)
   2482 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2483 	*length = unpack_uint32_(buffer, length_len);
   2484 
   2485 	if(0 != *data)
   2486 		free(*data);
   2487 
   2488 	if(0 == (*data = safe_malloc_add_2op_(*length, /*+*/1)))
   2489 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2490 
   2491 	if(*length > 0) {
   2492 		if(read_cb(*data, 1, *length, handle) != *length)
   2493 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2494 	}
   2495 
   2496 	(*data)[*length] = '\0';
   2497 
   2498 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2499 }
   2500 
   2501 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Picture *block)
   2502 {
   2503 	FLAC__Metadata_SimpleIteratorStatus status;
   2504 	FLAC__byte buffer[4]; /* asserted below that this is big enough */
   2505 	FLAC__uint32 len;
   2506 
   2507 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
   2508 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
   2509 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
   2510 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
   2511 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
   2512 
   2513 	FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_TYPE_LEN % 8 == 0);
   2514 	len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN / 8;
   2515 	if(read_cb(buffer, 1, len, handle) != len)
   2516 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2517 	block->type = (FLAC__StreamMetadata_Picture_Type)unpack_uint32_(buffer, len);
   2518 
   2519 	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)
   2520 		return status;
   2521 
   2522 	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)
   2523 		return status;
   2524 
   2525 	FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN % 8 == 0);
   2526 	len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN / 8;
   2527 	if(read_cb(buffer, 1, len, handle) != len)
   2528 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2529 	block->width = unpack_uint32_(buffer, len);
   2530 
   2531 	FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN % 8 == 0);
   2532 	len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN / 8;
   2533 	if(read_cb(buffer, 1, len, handle) != len)
   2534 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2535 	block->height = unpack_uint32_(buffer, len);
   2536 
   2537 	FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN % 8 == 0);
   2538 	len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN / 8;
   2539 	if(read_cb(buffer, 1, len, handle) != len)
   2540 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2541 	block->depth = unpack_uint32_(buffer, len);
   2542 
   2543 	FLAC__ASSERT(FLAC__STREAM_METADATA_PICTURE_COLORS_LEN % 8 == 0);
   2544 	len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN / 8;
   2545 	if(read_cb(buffer, 1, len, handle) != len)
   2546 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2547 	block->colors = unpack_uint32_(buffer, len);
   2548 
   2549 	/* for convenience we use read_metadata_block_data_picture_cstring_cb_() even though it adds an extra terminating NUL we don't use */
   2550 	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)
   2551 		return status;
   2552 
   2553 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2554 }
   2555 
   2556 FLAC__Metadata_SimpleIteratorStatus read_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__StreamMetadata_Unknown *block, unsigned block_length)
   2557 {
   2558 	if(block_length == 0) {
   2559 		block->data = 0;
   2560 	}
   2561 	else {
   2562 		if(0 == (block->data = malloc(block_length)))
   2563 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2564 
   2565 		if(read_cb(block->data, 1, block_length, handle) != block_length)
   2566 			return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   2567 	}
   2568 
   2569 	return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2570 }
   2571 
   2572 FLAC__bool write_metadata_block_header_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
   2573 {
   2574 	FLAC__ASSERT(0 != file);
   2575 	FLAC__ASSERT(0 != status);
   2576 
   2577 	if(!write_metadata_block_header_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
   2578 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   2579 		return false;
   2580 	}
   2581 
   2582 	return true;
   2583 }
   2584 
   2585 FLAC__bool write_metadata_block_data_(FILE *file, FLAC__Metadata_SimpleIteratorStatus *status, const FLAC__StreamMetadata *block)
   2586 {
   2587 	FLAC__ASSERT(0 != file);
   2588 	FLAC__ASSERT(0 != status);
   2589 
   2590 	if (write_metadata_block_data_cb_((FLAC__IOHandle)file, (FLAC__IOCallback_Write)fwrite, block)) {
   2591 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK;
   2592 		return true;
   2593 	}
   2594 	else {
   2595 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   2596 		return false;
   2597 	}
   2598 }
   2599 
   2600 FLAC__bool write_metadata_block_header_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
   2601 {
   2602 	FLAC__byte buffer[FLAC__STREAM_METADATA_HEADER_LENGTH];
   2603 
   2604 	FLAC__ASSERT(block->length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
   2605 	/* double protection */
   2606 	if(block->length >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN))
   2607 		return false;
   2608 
   2609 	buffer[0] = (block->is_last? 0x80 : 0) | (FLAC__byte)block->type;
   2610 	pack_uint32_(block->length, buffer + 1, 3);
   2611 
   2612 	if(write_cb(buffer, 1, FLAC__STREAM_METADATA_HEADER_LENGTH, handle) != FLAC__STREAM_METADATA_HEADER_LENGTH)
   2613 		return false;
   2614 
   2615 	return true;
   2616 }
   2617 
   2618 FLAC__bool write_metadata_block_data_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata *block)
   2619 {
   2620 	FLAC__ASSERT(0 != block);
   2621 
   2622 	switch(block->type) {
   2623 		case FLAC__METADATA_TYPE_STREAMINFO:
   2624 			return write_metadata_block_data_streaminfo_cb_(handle, write_cb, &block->data.stream_info);
   2625 		case FLAC__METADATA_TYPE_PADDING:
   2626 			return write_metadata_block_data_padding_cb_(handle, write_cb, &block->data.padding, block->length);
   2627 		case FLAC__METADATA_TYPE_APPLICATION:
   2628 			return write_metadata_block_data_application_cb_(handle, write_cb, &block->data.application, block->length);
   2629 		case FLAC__METADATA_TYPE_SEEKTABLE:
   2630 			return write_metadata_block_data_seektable_cb_(handle, write_cb, &block->data.seek_table);
   2631 		case FLAC__METADATA_TYPE_VORBIS_COMMENT:
   2632 			return write_metadata_block_data_vorbis_comment_cb_(handle, write_cb, &block->data.vorbis_comment);
   2633 		case FLAC__METADATA_TYPE_CUESHEET:
   2634 			return write_metadata_block_data_cuesheet_cb_(handle, write_cb, &block->data.cue_sheet);
   2635 		case FLAC__METADATA_TYPE_PICTURE:
   2636 			return write_metadata_block_data_picture_cb_(handle, write_cb, &block->data.picture);
   2637 		default:
   2638 			return write_metadata_block_data_unknown_cb_(handle, write_cb, &block->data.unknown, block->length);
   2639 	}
   2640 }
   2641 
   2642 FLAC__bool write_metadata_block_data_streaminfo_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_StreamInfo *block)
   2643 {
   2644 	FLAC__byte buffer[FLAC__STREAM_METADATA_STREAMINFO_LENGTH];
   2645 	const unsigned channels1 = block->channels - 1;
   2646 	const unsigned bps1 = block->bits_per_sample - 1;
   2647 
   2648 	/* we are using hardcoded numbers for simplicity but we should
   2649 	 * probably eventually write a bit-level packer and use the
   2650 	 * _STREAMINFO_ constants.
   2651 	 */
   2652 	pack_uint32_(block->min_blocksize, buffer, 2);
   2653 	pack_uint32_(block->max_blocksize, buffer+2, 2);
   2654 	pack_uint32_(block->min_framesize, buffer+4, 3);
   2655 	pack_uint32_(block->max_framesize, buffer+7, 3);
   2656 	buffer[10] = (block->sample_rate >> 12) & 0xff;
   2657 	buffer[11] = (block->sample_rate >> 4) & 0xff;
   2658 	buffer[12] = ((block->sample_rate & 0x0f) << 4) | (channels1 << 1) | (bps1 >> 4);
   2659 	buffer[13] = (FLAC__byte)(((bps1 & 0x0f) << 4) | ((block->total_samples >> 32) & 0x0f));
   2660 	pack_uint32_((FLAC__uint32)block->total_samples, buffer+14, 4);
   2661 	memcpy(buffer+18, block->md5sum, 16);
   2662 
   2663 	if(write_cb(buffer, 1, FLAC__STREAM_METADATA_STREAMINFO_LENGTH, handle) != FLAC__STREAM_METADATA_STREAMINFO_LENGTH)
   2664 		return false;
   2665 
   2666 	return true;
   2667 }
   2668 
   2669 FLAC__bool write_metadata_block_data_padding_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Padding *block, unsigned block_length)
   2670 {
   2671 	unsigned i, n = block_length;
   2672 	FLAC__byte buffer[1024];
   2673 
   2674 	(void)block;
   2675 
   2676 	memset(buffer, 0, 1024);
   2677 
   2678 	for(i = 0; i < n/1024; i++)
   2679 		if(write_cb(buffer, 1, 1024, handle) != 1024)
   2680 			return false;
   2681 
   2682 	n %= 1024;
   2683 
   2684 	if(write_cb(buffer, 1, n, handle) != n)
   2685 		return false;
   2686 
   2687 	return true;
   2688 }
   2689 
   2690 FLAC__bool write_metadata_block_data_application_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Application *block, unsigned block_length)
   2691 {
   2692 	const unsigned id_bytes = FLAC__STREAM_METADATA_APPLICATION_ID_LEN / 8;
   2693 
   2694 	if(write_cb(block->id, 1, id_bytes, handle) != id_bytes)
   2695 		return false;
   2696 
   2697 	block_length -= id_bytes;
   2698 
   2699 	if(write_cb(block->data, 1, block_length, handle) != block_length)
   2700 		return false;
   2701 
   2702 	return true;
   2703 }
   2704 
   2705 FLAC__bool write_metadata_block_data_seektable_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_SeekTable *block)
   2706 {
   2707 	unsigned i;
   2708 	FLAC__byte buffer[FLAC__STREAM_METADATA_SEEKPOINT_LENGTH];
   2709 
   2710 	for(i = 0; i < block->num_points; i++) {
   2711 		/* some MAGIC NUMBERs here */
   2712 		pack_uint64_(block->points[i].sample_number, buffer, 8);
   2713 		pack_uint64_(block->points[i].stream_offset, buffer+8, 8);
   2714 		pack_uint32_(block->points[i].frame_samples, buffer+16, 2);
   2715 		if(write_cb(buffer, 1, FLAC__STREAM_METADATA_SEEKPOINT_LENGTH, handle) != FLAC__STREAM_METADATA_SEEKPOINT_LENGTH)
   2716 			return false;
   2717 	}
   2718 
   2719 	return true;
   2720 }
   2721 
   2722 FLAC__bool write_metadata_block_data_vorbis_comment_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_VorbisComment *block)
   2723 {
   2724 	unsigned i;
   2725 	const unsigned entry_length_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN / 8;
   2726 	const unsigned num_comments_len = FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN / 8;
   2727 	FLAC__byte buffer[4]; /* magic number is asserted below */
   2728 
   2729 	FLAC__ASSERT(flac_max(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN, FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN) / 8 == sizeof(buffer));
   2730 
   2731 	pack_uint32_little_endian_(block->vendor_string.length, buffer, entry_length_len);
   2732 	if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
   2733 		return false;
   2734 	if(write_cb(block->vendor_string.entry, 1, block->vendor_string.length, handle) != block->vendor_string.length)
   2735 		return false;
   2736 
   2737 	pack_uint32_little_endian_(block->num_comments, buffer, num_comments_len);
   2738 	if(write_cb(buffer, 1, num_comments_len, handle) != num_comments_len)
   2739 		return false;
   2740 
   2741 	for(i = 0; i < block->num_comments; i++) {
   2742 		pack_uint32_little_endian_(block->comments[i].length, buffer, entry_length_len);
   2743 		if(write_cb(buffer, 1, entry_length_len, handle) != entry_length_len)
   2744 			return false;
   2745 		if(write_cb(block->comments[i].entry, 1, block->comments[i].length, handle) != block->comments[i].length)
   2746 			return false;
   2747 	}
   2748 
   2749 	return true;
   2750 }
   2751 
   2752 FLAC__bool write_metadata_block_data_cuesheet_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_CueSheet *block)
   2753 {
   2754 	unsigned i, j, len;
   2755 	FLAC__byte buffer[1024]; /* asserted below that this is big enough */
   2756 
   2757 	FLAC__ASSERT(sizeof(buffer) >= sizeof(FLAC__uint64));
   2758 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN/8);
   2759 	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);
   2760 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN/8);
   2761 
   2762 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
   2763 	len = FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN / 8;
   2764 	if(write_cb(block->media_catalog_number, 1, len, handle) != len)
   2765 		return false;
   2766 
   2767 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN % 8 == 0);
   2768 	len = FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN / 8;
   2769 	pack_uint64_(block->lead_in, buffer, len);
   2770 	if(write_cb(buffer, 1, len, handle) != len)
   2771 		return false;
   2772 
   2773 	FLAC__ASSERT((FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) % 8 == 0);
   2774 	len = (FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN + FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN) / 8;
   2775 	memset(buffer, 0, len);
   2776 	if(block->is_cd)
   2777 		buffer[0] |= 0x80;
   2778 	if(write_cb(buffer, 1, len, handle) != len)
   2779 		return false;
   2780 
   2781 	FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN % 8 == 0);
   2782 	len = FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN / 8;
   2783 	pack_uint32_(block->num_tracks, buffer, len);
   2784 	if(write_cb(buffer, 1, len, handle) != len)
   2785 		return false;
   2786 
   2787 	for(i = 0; i < block->num_tracks; i++) {
   2788 		FLAC__StreamMetadata_CueSheet_Track *track = block->tracks + i;
   2789 
   2790 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN % 8 == 0);
   2791 		len = FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN / 8;
   2792 		pack_uint64_(track->offset, buffer, len);
   2793 		if(write_cb(buffer, 1, len, handle) != len)
   2794 			return false;
   2795 
   2796 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN % 8 == 0);
   2797 		len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN / 8;
   2798 		pack_uint32_(track->number, buffer, len);
   2799 		if(write_cb(buffer, 1, len, handle) != len)
   2800 			return false;
   2801 
   2802 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
   2803 		len = FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN / 8;
   2804 		if(write_cb(track->isrc, 1, len, handle) != len)
   2805 			return false;
   2806 
   2807 		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);
   2808 		len = (FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN + FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN) / 8;
   2809 		memset(buffer, 0, len);
   2810 		buffer[0] = (track->type << 7) | (track->pre_emphasis << 6);
   2811 		if(write_cb(buffer, 1, len, handle) != len)
   2812 			return false;
   2813 
   2814 		FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN % 8 == 0);
   2815 		len = FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN / 8;
   2816 		pack_uint32_(track->num_indices, buffer, len);
   2817 		if(write_cb(buffer, 1, len, handle) != len)
   2818 			return false;
   2819 
   2820 		for(j = 0; j < track->num_indices; j++) {
   2821 			FLAC__StreamMetadata_CueSheet_Index *indx = track->indices + j;
   2822 
   2823 			FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN % 8 == 0);
   2824 			len = FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN / 8;
   2825 			pack_uint64_(indx->offset, buffer, len);
   2826 			if(write_cb(buffer, 1, len, handle) != len)
   2827 				return false;
   2828 
   2829 			FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN % 8 == 0);
   2830 			len = FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN / 8;
   2831 			pack_uint32_(indx->number, buffer, len);
   2832 			if(write_cb(buffer, 1, len, handle) != len)
   2833 				return false;
   2834 
   2835 			FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN % 8 == 0);
   2836 			len = FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN / 8;
   2837 			memset(buffer, 0, len);
   2838 			if(write_cb(buffer, 1, len, handle) != len)
   2839 				return false;
   2840 		}
   2841 	}
   2842 
   2843 	return true;
   2844 }
   2845 
   2846 FLAC__bool write_metadata_block_data_picture_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Picture *block)
   2847 {
   2848 	unsigned len;
   2849 	size_t slen;
   2850 	FLAC__byte buffer[4]; /* magic number is asserted below */
   2851 
   2852 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_TYPE_LEN%8);
   2853 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN%8);
   2854 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN%8);
   2855 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN%8);
   2856 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN%8);
   2857 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN%8);
   2858 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_COLORS_LEN%8);
   2859 	FLAC__ASSERT(0 == FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN%8);
   2860 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8);
   2861 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8);
   2862 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8);
   2863 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8);
   2864 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8);
   2865 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8);
   2866 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8);
   2867 	FLAC__ASSERT(sizeof(buffer) >= FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8);
   2868 
   2869 	len = FLAC__STREAM_METADATA_PICTURE_TYPE_LEN/8;
   2870 	pack_uint32_(block->type, buffer, len);
   2871 	if(write_cb(buffer, 1, len, handle) != len)
   2872 		return false;
   2873 
   2874 	len = FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN/8;
   2875 	slen = strlen(block->mime_type);
   2876 	pack_uint32_(slen, buffer, len);
   2877 	if(write_cb(buffer, 1, len, handle) != len)
   2878 		return false;
   2879 	if(write_cb(block->mime_type, 1, slen, handle) != slen)
   2880 		return false;
   2881 
   2882 	len = FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN/8;
   2883 	slen = strlen((const char *)block->description);
   2884 	pack_uint32_(slen, buffer, len);
   2885 	if(write_cb(buffer, 1, len, handle) != len)
   2886 		return false;
   2887 	if(write_cb(block->description, 1, slen, handle) != slen)
   2888 		return false;
   2889 
   2890 	len = FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN/8;
   2891 	pack_uint32_(block->width, buffer, len);
   2892 	if(write_cb(buffer, 1, len, handle) != len)
   2893 		return false;
   2894 
   2895 	len = FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN/8;
   2896 	pack_uint32_(block->height, buffer, len);
   2897 	if(write_cb(buffer, 1, len, handle) != len)
   2898 		return false;
   2899 
   2900 	len = FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN/8;
   2901 	pack_uint32_(block->depth, buffer, len);
   2902 	if(write_cb(buffer, 1, len, handle) != len)
   2903 		return false;
   2904 
   2905 	len = FLAC__STREAM_METADATA_PICTURE_COLORS_LEN/8;
   2906 	pack_uint32_(block->colors, buffer, len);
   2907 	if(write_cb(buffer, 1, len, handle) != len)
   2908 		return false;
   2909 
   2910 	len = FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN/8;
   2911 	pack_uint32_(block->data_length, buffer, len);
   2912 	if(write_cb(buffer, 1, len, handle) != len)
   2913 		return false;
   2914 	if(write_cb(block->data, 1, block->data_length, handle) != block->data_length)
   2915 		return false;
   2916 
   2917 	return true;
   2918 }
   2919 
   2920 FLAC__bool write_metadata_block_data_unknown_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Write write_cb, const FLAC__StreamMetadata_Unknown *block, unsigned block_length)
   2921 {
   2922 	if(write_cb(block->data, 1, block_length, handle) != block_length)
   2923 		return false;
   2924 
   2925 	return true;
   2926 }
   2927 
   2928 FLAC__bool write_metadata_block_stationary_(FLAC__Metadata_SimpleIterator *iterator, const FLAC__StreamMetadata *block)
   2929 {
   2930 	if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
   2931 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2932 		return false;
   2933 	}
   2934 
   2935 	if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
   2936 		return false;
   2937 
   2938 	if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
   2939 		return false;
   2940 
   2941 	if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
   2942 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2943 		return false;
   2944 	}
   2945 
   2946 	return read_metadata_block_header_(iterator);
   2947 }
   2948 
   2949 FLAC__bool write_metadata_block_stationary_with_padding_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, unsigned padding_length, FLAC__bool padding_is_last)
   2950 {
   2951 	FLAC__StreamMetadata *padding;
   2952 
   2953 	if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
   2954 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2955 		return false;
   2956 	}
   2957 
   2958 	block->is_last = false;
   2959 
   2960 	if(!write_metadata_block_header_(iterator->file, &iterator->status, block))
   2961 		return false;
   2962 
   2963 	if(!write_metadata_block_data_(iterator->file, &iterator->status, block))
   2964 		return false;
   2965 
   2966 	if(0 == (padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)))
   2967 		return FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   2968 
   2969 	padding->is_last = padding_is_last;
   2970 	padding->length = padding_length;
   2971 
   2972 	if(!write_metadata_block_header_(iterator->file, &iterator->status, padding)) {
   2973 		FLAC__metadata_object_delete(padding);
   2974 		return false;
   2975 	}
   2976 
   2977 	if(!write_metadata_block_data_(iterator->file, &iterator->status, padding)) {
   2978 		FLAC__metadata_object_delete(padding);
   2979 		return false;
   2980 	}
   2981 
   2982 	FLAC__metadata_object_delete(padding);
   2983 
   2984 	if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
   2985 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   2986 		return false;
   2987 	}
   2988 
   2989 	return read_metadata_block_header_(iterator);
   2990 }
   2991 
   2992 FLAC__bool rewrite_whole_file_(FLAC__Metadata_SimpleIterator *iterator, FLAC__StreamMetadata *block, FLAC__bool append)
   2993 {
   2994 	FILE *tempfile = NULL;
   2995 	char *tempfilename = NULL;
   2996 	int fixup_is_last_code = 0; /* 0 => no need to change any is_last flags */
   2997 	FLAC__off_t fixup_is_last_flag_offset = -1;
   2998 
   2999 	FLAC__ASSERT(0 != block || append == false);
   3000 
   3001 	if(iterator->is_last) {
   3002 		if(append) {
   3003 			fixup_is_last_code = 1; /* 1 => clear the is_last flag at the following offset */
   3004 			fixup_is_last_flag_offset = iterator->offset[iterator->depth];
   3005 		}
   3006 		else if(0 == block) {
   3007 			simple_iterator_push_(iterator);
   3008 			if(!FLAC__metadata_simple_iterator_prev(iterator)) {
   3009 				(void)simple_iterator_pop_(iterator);
   3010 				return false;
   3011 			}
   3012 			fixup_is_last_code = -1; /* -1 => set the is_last the flag at the following offset */
   3013 			fixup_is_last_flag_offset = iterator->offset[iterator->depth];
   3014 			if(!simple_iterator_pop_(iterator))
   3015 				return false;
   3016 		}
   3017 	}
   3018 
   3019 	if(!simple_iterator_copy_file_prefix_(iterator, &tempfile, &tempfilename, append))
   3020 		return false;
   3021 
   3022 	if(0 != block) {
   3023 		if(!write_metadata_block_header_(tempfile, &iterator->status, block)) {
   3024 			cleanup_tempfile_(&tempfile, &tempfilename);
   3025 			return false;
   3026 		}
   3027 
   3028 		if(!write_metadata_block_data_(tempfile, &iterator->status, block)) {
   3029 			cleanup_tempfile_(&tempfile, &tempfilename);
   3030 			return false;
   3031 		}
   3032 	}
   3033 
   3034 	if(!simple_iterator_copy_file_postfix_(iterator, &tempfile, &tempfilename, fixup_is_last_code, fixup_is_last_flag_offset, block==0))
   3035 		return false;
   3036 
   3037 	if(append)
   3038 		return FLAC__metadata_simple_iterator_next(iterator);
   3039 
   3040 	return true;
   3041 }
   3042 
   3043 void simple_iterator_push_(FLAC__Metadata_SimpleIterator *iterator)
   3044 {
   3045 	FLAC__ASSERT(iterator->depth+1 < SIMPLE_ITERATOR_MAX_PUSH_DEPTH);
   3046 	iterator->offset[iterator->depth+1] = iterator->offset[iterator->depth];
   3047 	iterator->depth++;
   3048 }
   3049 
   3050 FLAC__bool simple_iterator_pop_(FLAC__Metadata_SimpleIterator *iterator)
   3051 {
   3052 	FLAC__ASSERT(iterator->depth > 0);
   3053 	iterator->depth--;
   3054 	if(0 != fseeko(iterator->file, iterator->offset[iterator->depth], SEEK_SET)) {
   3055 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   3056 		return false;
   3057 	}
   3058 
   3059 	return read_metadata_block_header_(iterator);
   3060 }
   3061 
   3062 /* return meanings:
   3063  * 0: ok
   3064  * 1: read error
   3065  * 2: seek error
   3066  * 3: not a FLAC file
   3067  */
   3068 unsigned seek_to_first_metadata_block_cb_(FLAC__IOHandle handle, FLAC__IOCallback_Read read_cb, FLAC__IOCallback_Seek seek_cb)
   3069 {
   3070 	FLAC__byte buffer[4];
   3071 	size_t n;
   3072 	unsigned i;
   3073 
   3074 	FLAC__ASSERT(FLAC__STREAM_SYNC_LENGTH == sizeof(buffer));
   3075 
   3076 	/* skip any id3v2 tag */
   3077 	errno = 0;
   3078 	n = read_cb(buffer, 1, 4, handle);
   3079 	if(errno)
   3080 		return 1;
   3081 	else if(n != 4)
   3082 		return 3;
   3083 	else if(0 == memcmp(buffer, "ID3", 3)) {
   3084 		unsigned tag_length = 0;
   3085 
   3086 		/* skip to the tag length */
   3087 		if(seek_cb(handle, 2, SEEK_CUR) < 0)
   3088 			return 2;
   3089 
   3090 		/* read the length */
   3091 		for(i = 0; i < 4; i++) {
   3092 			if(read_cb(buffer, 1, 1, handle) < 1 || buffer[0] & 0x80)
   3093 				return 1;
   3094 			tag_length <<= 7;
   3095 			tag_length |= (buffer[0] & 0x7f);
   3096 		}
   3097 
   3098 		/* skip the rest of the tag */
   3099 		if(seek_cb(handle, tag_length, SEEK_CUR) < 0)
   3100 			return 2;
   3101 
   3102 		/* read the stream sync code */
   3103 		errno = 0;
   3104 		n = read_cb(buffer, 1, 4, handle);
   3105 		if(errno)
   3106 			return 1;
   3107 		else if(n != 4)
   3108 			return 3;
   3109 	}
   3110 
   3111 	/* check for the fLaC signature */
   3112 	if(0 == memcmp(FLAC__STREAM_SYNC_STRING, buffer, FLAC__STREAM_SYNC_LENGTH))
   3113 		return 0;
   3114 	else
   3115 		return 3;
   3116 }
   3117 
   3118 unsigned seek_to_first_metadata_block_(FILE *f)
   3119 {
   3120 	return seek_to_first_metadata_block_cb_((FLAC__IOHandle)f, (FLAC__IOCallback_Read)fread, fseek_wrapper_);
   3121 }
   3122 
   3123 FLAC__bool simple_iterator_copy_file_prefix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, FLAC__bool append)
   3124 {
   3125 	const FLAC__off_t offset_end = append? iterator->offset[iterator->depth] + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (FLAC__off_t)iterator->length : iterator->offset[iterator->depth];
   3126 
   3127 	if(0 != fseeko(iterator->file, 0, SEEK_SET)) {
   3128 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   3129 		return false;
   3130 	}
   3131 	if(!open_tempfile_(iterator->filename, iterator->tempfile_path_prefix, tempfile, tempfilename, &iterator->status)) {
   3132 		cleanup_tempfile_(tempfile, tempfilename);
   3133 		return false;
   3134 	}
   3135 	if(!copy_n_bytes_from_file_(iterator->file, *tempfile, offset_end, &iterator->status)) {
   3136 		cleanup_tempfile_(tempfile, tempfilename);
   3137 		return false;
   3138 	}
   3139 
   3140 	return true;
   3141 }
   3142 
   3143 FLAC__bool simple_iterator_copy_file_postfix_(FLAC__Metadata_SimpleIterator *iterator, FILE **tempfile, char **tempfilename, int fixup_is_last_code, FLAC__off_t fixup_is_last_flag_offset, FLAC__bool backup)
   3144 {
   3145 	FLAC__off_t save_offset = iterator->offset[iterator->depth];
   3146 	FLAC__ASSERT(0 != *tempfile);
   3147 
   3148 	if(0 != fseeko(iterator->file, save_offset + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (FLAC__off_t)iterator->length, SEEK_SET)) {
   3149 		cleanup_tempfile_(tempfile, tempfilename);
   3150 		iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   3151 		return false;
   3152 	}
   3153 	if(!copy_remaining_bytes_from_file_(iterator->file, *tempfile, &iterator->status)) {
   3154 		cleanup_tempfile_(tempfile, tempfilename);
   3155 		return false;
   3156 	}
   3157 
   3158 	if(fixup_is_last_code != 0) {
   3159 		/*
   3160 		 * if code == 1, it means a block was appended to the end so
   3161 		 *   we have to clear the is_last flag of the previous block
   3162 		 * if code == -1, it means the last block was deleted so
   3163 		 *   we have to set the is_last flag of the previous block
   3164 		 */
   3165 		/* MAGIC NUMBERs here; we know the is_last flag is the high bit of the byte at this location */
   3166 		FLAC__byte x;
   3167 		if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
   3168 			cleanup_tempfile_(tempfile, tempfilename);
   3169 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   3170 			return false;
   3171 		}
   3172 		if(fread(&x, 1, 1, *tempfile) != 1) {
   3173 			cleanup_tempfile_(tempfile, tempfilename);
   3174 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   3175 			return false;
   3176 		}
   3177 		if(fixup_is_last_code > 0) {
   3178 			FLAC__ASSERT(x & 0x80);
   3179 			x &= 0x7f;
   3180 		}
   3181 		else {
   3182 			FLAC__ASSERT(!(x & 0x80));
   3183 			x |= 0x80;
   3184 		}
   3185 		if(0 != fseeko(*tempfile, fixup_is_last_flag_offset, SEEK_SET)) {
   3186 			cleanup_tempfile_(tempfile, tempfilename);
   3187 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR;
   3188 			return false;
   3189 		}
   3190 		if(local__fwrite(&x, 1, 1, *tempfile) != 1) {
   3191 			cleanup_tempfile_(tempfile, tempfilename);
   3192 			iterator->status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   3193 			return false;
   3194 		}
   3195 	}
   3196 
   3197 	(void)fclose(iterator->file);
   3198 
   3199 	if(!transport_tempfile_(iterator->filename, tempfile, tempfilename, &iterator->status))
   3200 		return false;
   3201 
   3202 	if(iterator->has_stats)
   3203 		set_file_stats_(iterator->filename, &iterator->stats);
   3204 
   3205 	if(!simple_iterator_prime_input_(iterator, !iterator->is_writable))
   3206 		return false;
   3207 	if(backup) {
   3208 		while(iterator->offset[iterator->depth] + (FLAC__off_t)FLAC__STREAM_METADATA_HEADER_LENGTH + (FLAC__off_t)iterator->length < save_offset)
   3209 			if(!FLAC__metadata_simple_iterator_next(iterator))
   3210 				return false;
   3211 		return true;
   3212 	}
   3213 	else {
   3214 		/* move the iterator to it's original block faster by faking a push, then doing a pop_ */
   3215 		FLAC__ASSERT(iterator->depth == 0);
   3216 		iterator->offset[0] = save_offset;
   3217 		iterator->depth++;
   3218 		return simple_iterator_pop_(iterator);
   3219 	}
   3220 }
   3221 
   3222 FLAC__bool copy_n_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
   3223 {
   3224 	FLAC__byte buffer[8192];
   3225 	size_t n;
   3226 
   3227 	FLAC__ASSERT(bytes >= 0);
   3228 	while(bytes > 0) {
   3229 		n = flac_min(sizeof(buffer), (size_t)bytes);
   3230 		if(fread(buffer, 1, n, file) != n) {
   3231 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   3232 			return false;
   3233 		}
   3234 		if(local__fwrite(buffer, 1, n, tempfile) != n) {
   3235 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   3236 			return false;
   3237 		}
   3238 		bytes -= n;
   3239 	}
   3240 
   3241 	return true;
   3242 }
   3243 
   3244 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, FLAC__off_t bytes, FLAC__Metadata_SimpleIteratorStatus *status)
   3245 {
   3246 	FLAC__byte buffer[8192];
   3247 	size_t n;
   3248 
   3249 	FLAC__ASSERT(bytes >= 0);
   3250 	while(bytes > 0) {
   3251 		n = flac_min(sizeof(buffer), (size_t)bytes);
   3252 		if(read_cb(buffer, 1, n, handle) != n) {
   3253 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   3254 			return false;
   3255 		}
   3256 		if(temp_write_cb(buffer, 1, n, temp_handle) != n) {
   3257 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   3258 			return false;
   3259 		}
   3260 		bytes -= n;
   3261 	}
   3262 
   3263 	return true;
   3264 }
   3265 
   3266 FLAC__bool copy_remaining_bytes_from_file_(FILE *file, FILE *tempfile, FLAC__Metadata_SimpleIteratorStatus *status)
   3267 {
   3268 	FLAC__byte buffer[8192];
   3269 	size_t n;
   3270 
   3271 	while(!feof(file)) {
   3272 		n = fread(buffer, 1, sizeof(buffer), file);
   3273 		if(n == 0 && !feof(file)) {
   3274 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   3275 			return false;
   3276 		}
   3277 		if(n > 0 && local__fwrite(buffer, 1, n, tempfile) != n) {
   3278 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   3279 			return false;
   3280 		}
   3281 	}
   3282 
   3283 	return true;
   3284 }
   3285 
   3286 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)
   3287 {
   3288 	FLAC__byte buffer[8192];
   3289 	size_t n;
   3290 
   3291 	while(!eof_cb(handle)) {
   3292 		n = read_cb(buffer, 1, sizeof(buffer), handle);
   3293 		if(n == 0 && !eof_cb(handle)) {
   3294 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR;
   3295 			return false;
   3296 		}
   3297 		if(n > 0 && temp_write_cb(buffer, 1, n, temp_handle) != n) {
   3298 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR;
   3299 			return false;
   3300 		}
   3301 	}
   3302 
   3303 	return true;
   3304 }
   3305 
   3306 static int
   3307 local_snprintf(char *str, size_t size, const char *fmt, ...)
   3308 {
   3309 	va_list va;
   3310 	int rc;
   3311 
   3312 #if defined _MSC_VER
   3313 	if (size == 0)
   3314 		return 1024;
   3315 #endif
   3316 
   3317 	va_start (va, fmt);
   3318 
   3319 #if defined _MSC_VER
   3320 	rc = vsnprintf_s (str, size, _TRUNCATE, fmt, va);
   3321 	if (rc < 0)
   3322 		rc = size - 1;
   3323 #elif defined __MINGW32__
   3324 	rc = __mingw_vsnprintf (str, size, fmt, va);
   3325 #else
   3326 	rc = vsnprintf (str, size, fmt, va);
   3327 #endif
   3328 	va_end (va);
   3329 
   3330 	return rc;
   3331 }
   3332 
   3333 FLAC__bool open_tempfile_(const char *filename, const char *tempfile_path_prefix, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
   3334 {
   3335 	static const char *tempfile_suffix = ".metadata_edit";
   3336 	if(0 == tempfile_path_prefix) {
   3337 		size_t dest_len = strlen(filename) + strlen(tempfile_suffix) + 1;
   3338 		if(0 == (*tempfilename = safe_malloc_(dest_len))) {
   3339 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   3340 			return false;
   3341 		}
   3342 		local_snprintf(*tempfilename, dest_len, "%s%s", filename, tempfile_suffix);
   3343 	}
   3344 	else {
   3345 		const char *p = strrchr(filename, '/');
   3346 		size_t dest_len;
   3347 		if(0 == p)
   3348 			p = filename;
   3349 		else
   3350 			p++;
   3351 
   3352 		dest_len = strlen(tempfile_path_prefix) + strlen(p) + strlen(tempfile_suffix) + 2;
   3353 
   3354 		if(0 == (*tempfilename = safe_malloc_(dest_len))) {
   3355 			*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR;
   3356 			return false;
   3357 		}
   3358 		local_snprintf(*tempfilename, dest_len, "%s/%s%s", tempfile_path_prefix, p, tempfile_suffix);
   3359 	}
   3360 
   3361 	if(0 == (*tempfile = flac_fopen(*tempfilename, "w+b"))) {
   3362 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE;
   3363 		return false;
   3364 	}
   3365 
   3366 	return true;
   3367 }
   3368 
   3369 FLAC__bool transport_tempfile_(const char *filename, FILE **tempfile, char **tempfilename, FLAC__Metadata_SimpleIteratorStatus *status)
   3370 {
   3371 	FLAC__ASSERT(0 != filename);
   3372 	FLAC__ASSERT(0 != tempfile);
   3373 	FLAC__ASSERT(0 != *tempfile);
   3374 	FLAC__ASSERT(0 != tempfilename);
   3375 	FLAC__ASSERT(0 != *tempfilename);
   3376 	FLAC__ASSERT(0 != status);
   3377 
   3378 	(void)fclose(*tempfile);
   3379 	*tempfile = 0;
   3380 
   3381 #if defined _MSC_VER || defined __BORLANDC__ || defined __MINGW32__ || defined __EMX__
   3382 	/* on some flavors of windows, flac_rename() will fail if the destination already exists */
   3383 	if(flac_unlink(filename) < 0) {
   3384 		cleanup_tempfile_(tempfile, tempfilename);
   3385 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR;
   3386 		return false;
   3387 	}
   3388 #endif
   3389 
   3390 	/*@@@ to fully support the tempfile_path_prefix we need to update this piece to actually copy across filesystems instead of just flac_rename(): */
   3391 	if(0 != flac_rename(*tempfilename, filename)) {
   3392 		cleanup_tempfile_(tempfile, tempfilename);
   3393 		*status = FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR;
   3394 		return false;
   3395 	}
   3396 
   3397 	cleanup_tempfile_(tempfile, tempfilename);
   3398 
   3399 	return true;
   3400 }
   3401 
   3402 void cleanup_tempfile_(FILE **tempfile, char **tempfilename)
   3403 {
   3404 	if(0 != *tempfile) {
   3405 		(void)fclose(*tempfile);
   3406 		*tempfile = 0;
   3407 	}
   3408 
   3409 	if(0 != *tempfilename) {
   3410 		(void)flac_unlink(*tempfilename);
   3411 		free(*tempfilename);
   3412 		*tempfilename = 0;
   3413 	}
   3414 }
   3415 
   3416 FLAC__bool get_file_stats_(const char *filename, struct flac_stat_s *stats)
   3417 {
   3418 	FLAC__ASSERT(0 != filename);
   3419 	FLAC__ASSERT(0 != stats);
   3420 	return (0 == flac_stat(filename, stats));
   3421 }
   3422 
   3423 void set_file_stats_(const char *filename, struct flac_stat_s *stats)
   3424 {
   3425 	struct utimbuf srctime;
   3426 
   3427 	FLAC__ASSERT(0 != filename);
   3428 	FLAC__ASSERT(0 != stats);
   3429 
   3430 	srctime.actime = stats->st_atime;
   3431 	srctime.modtime = stats->st_mtime;
   3432 	(void)flac_chmod(filename, stats->st_mode);
   3433 	(void)flac_utime(filename, &srctime);
   3434 #if !defined _MSC_VER && !defined __BORLANDC__ && !defined __MINGW32__
   3435 	FLAC_CHECK_RETURN(chown(filename, stats->st_uid, -1));
   3436 	FLAC_CHECK_RETURN(chown(filename, -1, stats->st_gid));
   3437 #endif
   3438 }
   3439 
   3440 int fseek_wrapper_(FLAC__IOHandle handle, FLAC__int64 offset, int whence)
   3441 {
   3442 	return fseeko((FILE*)handle, (FLAC__off_t)offset, whence);
   3443 }
   3444 
   3445 FLAC__int64 ftell_wrapper_(FLAC__IOHandle handle)
   3446 {
   3447 	return ftello((FILE*)handle);
   3448 }
   3449 
   3450 FLAC__Metadata_ChainStatus get_equivalent_status_(FLAC__Metadata_SimpleIteratorStatus status)
   3451 {
   3452 	switch(status) {
   3453 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_OK:
   3454 			return FLAC__METADATA_CHAIN_STATUS_OK;
   3455 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
   3456 			return FLAC__METADATA_CHAIN_STATUS_ILLEGAL_INPUT;
   3457 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
   3458 			return FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE;
   3459 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
   3460 			return FLAC__METADATA_CHAIN_STATUS_NOT_A_FLAC_FILE;
   3461 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_WRITABLE:
   3462 			return FLAC__METADATA_CHAIN_STATUS_NOT_WRITABLE;
   3463 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_BAD_METADATA:
   3464 			return FLAC__METADATA_CHAIN_STATUS_BAD_METADATA;
   3465 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_READ_ERROR:
   3466 			return FLAC__METADATA_CHAIN_STATUS_READ_ERROR;
   3467 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_SEEK_ERROR:
   3468 			return FLAC__METADATA_CHAIN_STATUS_SEEK_ERROR;
   3469 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_WRITE_ERROR:
   3470 			return FLAC__METADATA_CHAIN_STATUS_WRITE_ERROR;
   3471 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_RENAME_ERROR:
   3472 			return FLAC__METADATA_CHAIN_STATUS_RENAME_ERROR;
   3473 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_UNLINK_ERROR:
   3474 			return FLAC__METADATA_CHAIN_STATUS_UNLINK_ERROR;
   3475 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_MEMORY_ALLOCATION_ERROR:
   3476 			return FLAC__METADATA_CHAIN_STATUS_MEMORY_ALLOCATION_ERROR;
   3477 		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_INTERNAL_ERROR:
   3478 		default:
   3479 			return FLAC__METADATA_CHAIN_STATUS_INTERNAL_ERROR;
   3480 	}
   3481 }
   3482