ref: 4770f60b183231822011b026c3e0aef1b70592ee
dir: /sys/src/cmd/audio/libFLAC/seekable_stream_decoder.c/
/* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2000,2001,2002,2003,2004 Josh Coalson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the Xiph.org Foundation nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h> /* for calloc() */
#include <string.h> /* for memcpy()/memcmp() */
#include "FLAC/assert.h"
#include "protected/seekable_stream_decoder.h"
#include "protected/stream_decoder.h"
#include "private/md5.h"
/* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
#ifdef _MSC_VER
#define FLAC__U64L(x) x
#else
#define FLAC__U64L(x) x##LLU
#endif
/***********************************************************************
*
* Private class method prototypes
*
***********************************************************************/
static void set_defaults_(FLAC__SeekableStreamDecoder *decoder);
static FLAC__StreamDecoderReadStatus read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data);
static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
static FLAC__bool seek_to_absolute_sample_(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample);
/***********************************************************************
*
* Private class data
*
***********************************************************************/
typedef struct FLAC__SeekableStreamDecoderPrivate {
FLAC__SeekableStreamDecoderReadCallback read_callback;
FLAC__SeekableStreamDecoderSeekCallback seek_callback;
FLAC__SeekableStreamDecoderTellCallback tell_callback;
FLAC__SeekableStreamDecoderLengthCallback length_callback;
FLAC__SeekableStreamDecoderEofCallback eof_callback;
FLAC__SeekableStreamDecoderWriteCallback write_callback;
FLAC__SeekableStreamDecoderMetadataCallback metadata_callback;
FLAC__SeekableStreamDecoderErrorCallback error_callback;
void *client_data;
FLAC__StreamDecoder *stream_decoder;
FLAC__bool do_md5_checking; /* initially gets protected_->md5_checking but is turned off after a seek */
struct FLAC__MD5Context md5context;
FLAC__byte stored_md5sum[16]; /* this is what is stored in the metadata */
FLAC__byte computed_md5sum[16]; /* this is the sum we computed from the decoded data */
/* the rest of these are only used for seeking: */
FLAC__StreamMetadata_StreamInfo stream_info; /* we keep this around so we can figure out how to seek quickly */
const FLAC__StreamMetadata_SeekTable *seek_table; /* we hold a pointer to the stream decoder's seek table for the same reason */
/* Since we always want to see the STREAMINFO and SEEK_TABLE blocks at this level, we need some extra flags to keep track of whether they should be passed on up through the metadata_callback */
FLAC__bool ignore_stream_info_block;
FLAC__bool ignore_seek_table_block;
FLAC__Frame last_frame; /* holds the info of the last frame we seeked to */
FLAC__uint64 target_sample;
} FLAC__SeekableStreamDecoderPrivate;
/***********************************************************************
*
* Public static class data
*
***********************************************************************/
FLAC_API const char * const FLAC__SeekableStreamDecoderStateString[] = {
"FLAC__SEEKABLE_STREAM_DECODER_OK",
"FLAC__SEEKABLE_STREAM_DECODER_SEEKING",
"FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM",
"FLAC__SEEKABLE_STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
"FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR",
"FLAC__SEEKABLE_STREAM_DECODER_READ_ERROR",
"FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR",
"FLAC__SEEKABLE_STREAM_DECODER_ALREADY_INITIALIZED",
"FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK",
"FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED"
};
FLAC_API const char * const FLAC__SeekableStreamDecoderReadStatusString[] = {
"FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_OK",
"FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_ERROR"
};
FLAC_API const char * const FLAC__SeekableStreamDecoderSeekStatusString[] = {
"FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK",
"FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_ERROR"
};
FLAC_API const char * const FLAC__SeekableStreamDecoderTellStatusString[] = {
"FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK",
"FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_ERROR"
};
FLAC_API const char * const FLAC__SeekableStreamDecoderLengthStatusString[] = {
"FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_OK",
"FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_ERROR"
};
/***********************************************************************
*
* Class constructor/destructor
*
***********************************************************************/
FLAC_API FLAC__SeekableStreamDecoder *FLAC__seekable_stream_decoder_new(void)
{
FLAC__SeekableStreamDecoder *decoder;
FLAC__ASSERT(sizeof(int) >= 4); /* we want to die right away if this is not true */
decoder = (FLAC__SeekableStreamDecoder*)calloc(1, sizeof(FLAC__SeekableStreamDecoder));
if(decoder == 0) {
return 0;
}
decoder->protected_ = (FLAC__SeekableStreamDecoderProtected*)calloc(1, sizeof(FLAC__SeekableStreamDecoderProtected));
if(decoder->protected_ == 0) {
free(decoder);
return 0;
}
decoder->private_ = (FLAC__SeekableStreamDecoderPrivate*)calloc(1, sizeof(FLAC__SeekableStreamDecoderPrivate));
if(decoder->private_ == 0) {
free(decoder->protected_);
free(decoder);
return 0;
}
decoder->private_->stream_decoder = FLAC__stream_decoder_new();
if(0 == decoder->private_->stream_decoder) {
free(decoder->private_);
free(decoder->protected_);
free(decoder);
return 0;
}
set_defaults_(decoder);
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED;
return decoder;
}
FLAC_API void FLAC__seekable_stream_decoder_delete(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
(void)FLAC__seekable_stream_decoder_finish(decoder);
FLAC__stream_decoder_delete(decoder->private_->stream_decoder);
free(decoder->private_);
free(decoder->protected_);
free(decoder);
}
/***********************************************************************
*
* Public class methods
*
***********************************************************************/
FLAC_API FLAC__SeekableStreamDecoderState FLAC__seekable_stream_decoder_init(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_ALREADY_INITIALIZED;
if(0 == decoder->private_->read_callback || 0 == decoder->private_->seek_callback || 0 == decoder->private_->tell_callback || 0 == decoder->private_->length_callback || 0 == decoder->private_->eof_callback)
return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK;
if(0 == decoder->private_->write_callback || 0 == decoder->private_->metadata_callback || 0 == decoder->private_->error_callback)
return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK;
decoder->private_->seek_table = 0;
decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
/* We initialize the FLAC__MD5Context even though we may never use it. This
* is because md5 checking may be turned on to start and then turned off if
* a seek occurs. So we always init the context here and finalize it in
* FLAC__seekable_stream_decoder_finish() to make sure things are always
* cleaned up properly.
*/
FLAC__MD5Init(&decoder->private_->md5context);
FLAC__stream_decoder_set_read_callback(decoder->private_->stream_decoder, read_callback_);
FLAC__stream_decoder_set_write_callback(decoder->private_->stream_decoder, write_callback_);
FLAC__stream_decoder_set_metadata_callback(decoder->private_->stream_decoder, metadata_callback_);
FLAC__stream_decoder_set_error_callback(decoder->private_->stream_decoder, error_callback_);
FLAC__stream_decoder_set_client_data(decoder->private_->stream_decoder, decoder);
/* We always want to see these blocks. Whether or not we pass them up
* through the metadata callback will be determined by flags set in our
* implementation of ..._set_metadata_respond/ignore...()
*/
FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_STREAMINFO);
FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_SEEKTABLE);
if(FLAC__stream_decoder_init(decoder->private_->stream_decoder) != FLAC__STREAM_DECODER_SEARCH_FOR_METADATA)
return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_finish(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__bool md5_failed = false;
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return true;
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
/* see the comment in FLAC__seekable_stream_decoder_init() as to why we
* always call FLAC__MD5Final()
*/
FLAC__MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);
FLAC__stream_decoder_finish(decoder->private_->stream_decoder);
if(decoder->private_->do_md5_checking) {
if(memcmp(decoder->private_->stored_md5sum, decoder->private_->computed_md5sum, 16))
md5_failed = true;
}
set_defaults_(decoder);
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED;
return !md5_failed;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_md5_checking(FLAC__SeekableStreamDecoder *decoder, FLAC__bool value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->protected_->md5_checking = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_read_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderReadCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->read_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_seek_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderSeekCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->seek_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_tell_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderTellCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->tell_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_length_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderLengthCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->length_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_eof_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderEofCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->eof_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_write_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderWriteCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->write_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderMetadataCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->metadata_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_error_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderErrorCallback value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->error_callback = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_client_data(FLAC__SeekableStreamDecoder *decoder, void *value)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->client_data = value;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond(FLAC__SeekableStreamDecoder *decoder, FLAC__MetadataType type)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
if(type == FLAC__METADATA_TYPE_STREAMINFO)
decoder->private_->ignore_stream_info_block = false;
else if(type == FLAC__METADATA_TYPE_SEEKTABLE)
decoder->private_->ignore_seek_table_block = false;
return FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, type);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond_application(FLAC__SeekableStreamDecoder *decoder, const FLAC__byte id[4])
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
return FLAC__stream_decoder_set_metadata_respond_application(decoder->private_->stream_decoder, id);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond_all(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->ignore_stream_info_block = false;
decoder->private_->ignore_seek_table_block = false;
return FLAC__stream_decoder_set_metadata_respond_all(decoder->private_->stream_decoder);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore(FLAC__SeekableStreamDecoder *decoder, FLAC__MetadataType type)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
if(type == FLAC__METADATA_TYPE_STREAMINFO) {
decoder->private_->ignore_stream_info_block = true;
return true;
}
else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
decoder->private_->ignore_seek_table_block = true;
return true;
}
else
return FLAC__stream_decoder_set_metadata_ignore(decoder->private_->stream_decoder, type);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore_application(FLAC__SeekableStreamDecoder *decoder, const FLAC__byte id[4])
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
return FLAC__stream_decoder_set_metadata_ignore_application(decoder->private_->stream_decoder, id);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore_all(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_->stream_decoder);
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
return false;
decoder->private_->ignore_stream_info_block = true;
decoder->private_->ignore_seek_table_block = true;
return
FLAC__stream_decoder_set_metadata_ignore_all(decoder->private_->stream_decoder) &&
FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_STREAMINFO) &&
FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_SEEKTABLE);
}
FLAC_API FLAC__SeekableStreamDecoderState FLAC__seekable_stream_decoder_get_state(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->protected_);
return decoder->protected_->state;
}
FLAC_API FLAC__StreamDecoderState FLAC__seekable_stream_decoder_get_stream_decoder_state(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_state(decoder->private_->stream_decoder);
}
FLAC_API const char *FLAC__seekable_stream_decoder_get_resolved_state_string(const FLAC__SeekableStreamDecoder *decoder)
{
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR)
return FLAC__SeekableStreamDecoderStateString[decoder->protected_->state];
else
return FLAC__stream_decoder_get_resolved_state_string(decoder->private_->stream_decoder);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_get_md5_checking(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->protected_);
return decoder->protected_->md5_checking;
}
FLAC_API unsigned FLAC__seekable_stream_decoder_get_channels(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_channels(decoder->private_->stream_decoder);
}
FLAC_API FLAC__ChannelAssignment FLAC__seekable_stream_decoder_get_channel_assignment(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_channel_assignment(decoder->private_->stream_decoder);
}
FLAC_API unsigned FLAC__seekable_stream_decoder_get_bits_per_sample(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_bits_per_sample(decoder->private_->stream_decoder);
}
FLAC_API unsigned FLAC__seekable_stream_decoder_get_sample_rate(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_sample_rate(decoder->private_->stream_decoder);
}
FLAC_API unsigned FLAC__seekable_stream_decoder_get_blocksize(const FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
return FLAC__stream_decoder_get_blocksize(decoder->private_->stream_decoder);
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_get_decode_position(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *position)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != position);
if(decoder->private_->tell_callback(decoder, position, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK)
return false;
FLAC__ASSERT(*position >= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder));
*position -= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder);
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_flush(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
decoder->private_->do_md5_checking = false;
if(!FLAC__stream_decoder_flush(decoder->private_->stream_decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_reset(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->protected_);
if(!FLAC__seekable_stream_decoder_flush(decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
if(!FLAC__stream_decoder_reset(decoder->private_->stream_decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
decoder->private_->seek_table = 0;
decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
/* We initialize the FLAC__MD5Context even though we may never use it. This
* is because md5 checking may be turned on to start and then turned off if
* a seek occurs. So we always init the context here and finalize it in
* FLAC__seekable_stream_decoder_finish() to make sure things are always
* cleaned up properly.
*/
FLAC__MD5Init(&decoder->private_->md5context);
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
return true;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_process_single(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__bool ret;
FLAC__ASSERT(0 != decoder);
if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
return true;
FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
ret = FLAC__stream_decoder_process_single(decoder->private_->stream_decoder);
if(!ret)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return ret;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_process_until_end_of_metadata(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__bool ret;
FLAC__ASSERT(0 != decoder);
if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
return true;
FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
ret = FLAC__stream_decoder_process_until_end_of_metadata(decoder->private_->stream_decoder);
if(!ret)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return ret;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_process_until_end_of_stream(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__bool ret;
FLAC__ASSERT(0 != decoder);
if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
return true;
FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
ret = FLAC__stream_decoder_process_until_end_of_stream(decoder->private_->stream_decoder);
if(!ret)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return ret;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_skip_single_frame(FLAC__SeekableStreamDecoder *decoder)
{
FLAC__bool ret;
FLAC__ASSERT(0 != decoder);
if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
return true;
FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
ret = FLAC__stream_decoder_skip_single_frame(decoder->private_->stream_decoder);
if(!ret)
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return ret;
}
FLAC_API FLAC__bool FLAC__seekable_stream_decoder_seek_absolute(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 sample)
{
FLAC__uint64 length;
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK || decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM);
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEKING;
/* turn off md5 checking if a seek is attempted */
decoder->private_->do_md5_checking = false;
if(!FLAC__stream_decoder_reset(decoder->private_->stream_decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
/* get the file length */
if(decoder->private_->length_callback(decoder, &length, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_OK) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
/* rewind */
if(decoder->private_->seek_callback(decoder, 0, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder->private_->stream_decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
if(decoder->private_->stream_info.total_samples > 0 && sample >= decoder->private_->stream_info.total_samples) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
return seek_to_absolute_sample_(decoder, length, sample);
}
/***********************************************************************
*
* Private class methods
*
***********************************************************************/
void set_defaults_(FLAC__SeekableStreamDecoder *decoder)
{
decoder->private_->read_callback = 0;
decoder->private_->seek_callback = 0;
decoder->private_->tell_callback = 0;
decoder->private_->length_callback = 0;
decoder->private_->eof_callback = 0;
decoder->private_->write_callback = 0;
decoder->private_->metadata_callback = 0;
decoder->private_->error_callback = 0;
decoder->private_->client_data = 0;
/* WATCHOUT: these should match the default behavior of FLAC__StreamDecoder */
decoder->private_->ignore_stream_info_block = false;
decoder->private_->ignore_seek_table_block = true;
decoder->protected_->md5_checking = false;
}
FLAC__StreamDecoderReadStatus read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data)
{
FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
(void)decoder;
if(seekable_stream_decoder->private_->eof_callback(seekable_stream_decoder, seekable_stream_decoder->private_->client_data)) {
*bytes = 0;
#if 0
@@@@@@ verify that this is not needed
seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
#endif
return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
}
else if(*bytes > 0) {
if(seekable_stream_decoder->private_->read_callback(seekable_stream_decoder, buffer, bytes, seekable_stream_decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_OK) {
seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_READ_ERROR;
return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
}
if(*bytes == 0) {
if(seekable_stream_decoder->private_->eof_callback(seekable_stream_decoder, seekable_stream_decoder->private_->client_data)) {
#if 0
@@@@@@ verify that this is not needed
seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
#endif
return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
}
else
return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}
else {
return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}
}
else
return FLAC__STREAM_DECODER_READ_STATUS_ABORT; /* abort to avoid a deadlock */
}
FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
{
FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
(void)decoder;
if(seekable_stream_decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
FLAC__uint64 this_frame_sample = frame->header.number.sample_number;
FLAC__uint64 next_frame_sample = this_frame_sample + (FLAC__uint64)frame->header.blocksize;
FLAC__uint64 target_sample = seekable_stream_decoder->private_->target_sample;
FLAC__ASSERT(frame->header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
seekable_stream_decoder->private_->last_frame = *frame; /* save the frame */
if(this_frame_sample <= target_sample && target_sample < next_frame_sample) { /* we hit our target frame */
unsigned delta = (unsigned)(target_sample - this_frame_sample);
/* kick out of seek mode */
seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
/* shift out the samples before target_sample */
if(delta > 0) {
unsigned channel;
const FLAC__int32 *newbuffer[FLAC__MAX_CHANNELS];
for(channel = 0; channel < frame->header.channels; channel++)
newbuffer[channel] = buffer[channel] + delta;
seekable_stream_decoder->private_->last_frame.header.blocksize -= delta;
seekable_stream_decoder->private_->last_frame.header.number.sample_number += (FLAC__uint64)delta;
/* write the relevant samples */
return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, &seekable_stream_decoder->private_->last_frame, newbuffer, seekable_stream_decoder->private_->client_data);
}
else {
/* write the relevant samples */
return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, frame, buffer, seekable_stream_decoder->private_->client_data);
}
}
else {
return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}
}
else {
if(seekable_stream_decoder->private_->do_md5_checking) {
if(!FLAC__MD5Accumulate(&seekable_stream_decoder->private_->md5context, buffer, frame->header.channels, frame->header.blocksize, (frame->header.bits_per_sample+7) / 8))
return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
}
return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, frame, buffer, seekable_stream_decoder->private_->client_data);
}
}
void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
{
FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
(void)decoder;
if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {
seekable_stream_decoder->private_->stream_info = metadata->data.stream_info;
/* save the MD5 signature for comparison later */
memcpy(seekable_stream_decoder->private_->stored_md5sum, metadata->data.stream_info.md5sum, 16);
if(0 == memcmp(seekable_stream_decoder->private_->stored_md5sum, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16))
seekable_stream_decoder->private_->do_md5_checking = false;
}
else if(metadata->type == FLAC__METADATA_TYPE_SEEKTABLE) {
seekable_stream_decoder->private_->seek_table = &metadata->data.seek_table;
}
if(seekable_stream_decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
FLAC__bool ignore_block = false;
if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO && seekable_stream_decoder->private_->ignore_stream_info_block)
ignore_block = true;
else if(metadata->type == FLAC__METADATA_TYPE_SEEKTABLE && seekable_stream_decoder->private_->ignore_seek_table_block)
ignore_block = true;
if(!ignore_block)
seekable_stream_decoder->private_->metadata_callback(seekable_stream_decoder, metadata, seekable_stream_decoder->private_->client_data);
}
}
void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
{
FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
(void)decoder;
if(seekable_stream_decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING)
seekable_stream_decoder->private_->error_callback(seekable_stream_decoder, status, seekable_stream_decoder->private_->client_data);
}
FLAC__bool seek_to_absolute_sample_(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample)
{
FLAC__uint64 first_frame_offset, lower_bound, upper_bound;
FLAC__int64 pos = -1, last_pos = -1;
int i, lower_seek_point = -1, upper_seek_point = -1;
unsigned approx_bytes_per_frame;
FLAC__uint64 last_frame_sample = FLAC__U64L(0xffffffffffffffff);
FLAC__bool needs_seek;
const FLAC__uint64 total_samples = decoder->private_->stream_info.total_samples;
const unsigned min_blocksize = decoder->private_->stream_info.min_blocksize;
const unsigned max_blocksize = decoder->private_->stream_info.max_blocksize;
const unsigned max_framesize = decoder->private_->stream_info.max_framesize;
const unsigned channels = FLAC__seekable_stream_decoder_get_channels(decoder);
const unsigned bps = FLAC__seekable_stream_decoder_get_bits_per_sample(decoder);
/* we are just guessing here, but we want to guess high, not low */
if(max_framesize > 0) {
approx_bytes_per_frame = max_framesize;
}
/*
* Check if it's a known fixed-blocksize stream. Note that though
* the spec doesn't allow zeroes in the STREAMINFO block, we may
* never get a STREAMINFO block when decoding so the value of
* min_blocksize might be zero.
*/
else if(min_blocksize == max_blocksize && min_blocksize > 0) {
/* note there are no () around 'bps/8' to keep precision up since it's an integer calulation */
approx_bytes_per_frame = min_blocksize * channels * bps/8 + 64;
}
else
approx_bytes_per_frame = 4608 * channels * bps/8 + 64;
/*
* The decode position is currently at the first frame since we
* rewound and processed metadata.
*/
if(!FLAC__seekable_stream_decoder_get_decode_position(decoder, &first_frame_offset)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
/*
* First, we set an upper and lower bound on where in the
* stream we will search. For now we assume the worst case
* scenario, which is our best guess at the beginning of
* the first and last frames.
*/
lower_bound = first_frame_offset;
/* calc the upper_bound, beyond which we never want to seek */
if(max_framesize > 0)
upper_bound = stream_length - (max_framesize + 128 + 2); /* 128 for a possible ID3V1 tag, 2 for indexing differences */
else
upper_bound = stream_length - ((channels * bps * FLAC__MAX_BLOCK_SIZE) / 8 + 128 + 2);
/*
* Now we refine the bounds if we have a seektable with
* suitable points. Note that according to the spec they
* must be ordered by ascending sample number.
*/
if(0 != decoder->private_->seek_table) {
/* find the closest seek point <= target_sample, if it exists */
for(i = (int)decoder->private_->seek_table->num_points - 1; i >= 0; i--) {
if(decoder->private_->seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && decoder->private_->seek_table->points[i].sample_number <= target_sample)
break;
}
if(i >= 0) { /* i.e. we found a suitable seek point... */
lower_bound = first_frame_offset + decoder->private_->seek_table->points[i].stream_offset;
lower_seek_point = i;
}
/* find the closest seek point > target_sample, if it exists */
for(i = 0; i < (int)decoder->private_->seek_table->num_points; i++) {
if(decoder->private_->seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && decoder->private_->seek_table->points[i].sample_number > target_sample)
break;
}
if(i < (int)decoder->private_->seek_table->num_points) { /* i.e. we found a suitable seek point... */
upper_bound = first_frame_offset + decoder->private_->seek_table->points[i].stream_offset;
upper_seek_point = i;
}
}
/*
* Now guess at where within those bounds our target
* sample will be.
*/
if(lower_seek_point >= 0) {
/* first see if our sample is within a few frames of the lower seekpoint */
if(decoder->private_->seek_table->points[lower_seek_point].sample_number <= target_sample && target_sample < decoder->private_->seek_table->points[lower_seek_point].sample_number + (decoder->private_->seek_table->points[lower_seek_point].frame_samples * 4)) {
pos = (FLAC__int64)lower_bound;
}
else if(upper_seek_point >= 0) {
const FLAC__uint64 target_offset = target_sample - decoder->private_->seek_table->points[lower_seek_point].sample_number;
const FLAC__uint64 range_samples = decoder->private_->seek_table->points[upper_seek_point].sample_number - decoder->private_->seek_table->points[lower_seek_point].sample_number;
const FLAC__uint64 range_bytes = upper_bound - lower_bound;
#if defined _MSC_VER || defined __MINGW32__
/* with VC++ you have to spoon feed it the casting */
pos = (FLAC__int64)lower_bound + (FLAC__int64)((double)(FLAC__int64)target_offset / (double)(FLAC__int64)range_samples * (double)(FLAC__int64)(range_bytes-1)) - approx_bytes_per_frame;
#else
pos = (FLAC__int64)lower_bound + (FLAC__int64)((double)target_offset / (double)range_samples * (double)(range_bytes-1)) - approx_bytes_per_frame;
#endif
}
}
/*
* If there's no seek table, we need to use the metadata (if we
* have it) and the filelength to estimate the position of the
* frame with the correct sample.
*/
if(pos < 0 && total_samples > 0) {
#if defined _MSC_VER || defined __MINGW32__
/* with VC++ you have to spoon feed it the casting */
pos = (FLAC__int64)first_frame_offset + (FLAC__int64)((double)(FLAC__int64)target_sample / (double)(FLAC__int64)total_samples * (double)(FLAC__int64)(stream_length-first_frame_offset-1)) - approx_bytes_per_frame;
#else
pos = (FLAC__int64)first_frame_offset + (FLAC__int64)((double)target_sample / (double)total_samples * (double)(stream_length-first_frame_offset-1)) - approx_bytes_per_frame;
#endif
}
/*
* If there's no seek table and total_samples is unknown, we
* don't even bother trying to figure out a target, we just use
* our current position.
*/
if(pos < 0) {
FLAC__uint64 upos;
if(decoder->private_->tell_callback(decoder, &upos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
pos = (FLAC__int64)upos;
needs_seek = false;
}
else
needs_seek = true;
/* clip the position to the bounds, lower bound takes precedence */
if(pos >= (FLAC__int64)upper_bound) {
pos = (FLAC__int64)upper_bound-1;
needs_seek = true;
}
if(pos < (FLAC__int64)lower_bound) {
pos = (FLAC__int64)lower_bound;
needs_seek = true;
}
decoder->private_->target_sample = target_sample;
while(1) {
if(needs_seek) {
if(decoder->private_->seek_callback(decoder, (FLAC__uint64)pos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
if(!FLAC__stream_decoder_flush(decoder->private_->stream_decoder)) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
return false;
}
}
/* Now we need to get a frame. It is possible for our seek
* to land in the middle of audio data that looks exactly like
* a frame header from a future version of an encoder. When
* that happens, FLAC__stream_decoder_process_single() will
* return false and the state will be
* FLAC__STREAM_DECODER_UNPARSEABLE_STREAM. But there is a
* remote possibility that it is properly synced at such a
* "future-codec frame", so to make sure, we wait to see
* several "unparseable" errors in a row before bailing out.
*/
{
unsigned unparseable_count;
FLAC__bool got_a_frame = false;
for (unparseable_count = 0; !got_a_frame && unparseable_count < 10; unparseable_count++) {
if(FLAC__stream_decoder_process_single(decoder->private_->stream_decoder))
got_a_frame = true;
else if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_UNPARSEABLE_STREAM)
/* try again. we don't want to flush the decoder since that clears the bitbuffer */
decoder->private_->stream_decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
else /* it's a real error */
break;
}
if (!got_a_frame) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
}
/* our write callback will change the state when it gets to the target frame */
if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
break;
}
else { /* we need to narrow the search */
const FLAC__uint64 this_frame_sample = decoder->private_->last_frame.header.number.sample_number;
FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
if(this_frame_sample == last_frame_sample && pos < last_pos) {
/* our last move backwards wasn't big enough, double it */
pos -= (last_pos - pos);
needs_seek = true;
}
else {
if(target_sample < this_frame_sample) {
last_pos = pos;
approx_bytes_per_frame = decoder->private_->last_frame.header.blocksize * channels * bps/8 + 64;
pos -= approx_bytes_per_frame;
needs_seek = true;
}
else { /* target_sample >= this_frame_sample + this frame's blocksize */
FLAC__uint64 upos;
if(decoder->private_->tell_callback(decoder, &upos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
last_pos = pos;
pos = (FLAC__int64)upos;
pos -= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder);
needs_seek = false;
/*
* if we haven't hit the target frame yet and our position hasn't changed,
* it means we're at the end of the stream and the seek target does not exist.
*/
if(last_pos == pos) {
decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
}
}
if(pos < (FLAC__int64)lower_bound)
pos = (FLAC__int64)lower_bound;
last_frame_sample = this_frame_sample;
}
}
return true;
}