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remove the commented-out and erroneous end-of-stream setting in read_callback_(); fix another bug in seeking where landing after the last frame start would cause a seek error; improve the infinite-loop checker

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This commit is contained in:
Josh Coalson 2004-09-25 23:49:00 +00:00
parent 8370a7b050
commit 732dbb2b7d
1 changed files with 43 additions and 15 deletions
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58
src/libOggFLAC/seekable_stream_decoder.c
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@ -79,6 +79,7 @@ typedef struct OggFLAC__SeekableStreamDecoderPrivate {
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__bool got_a_frame; /* hack needed in seek routine to check when process_single() actually writes a frame */
} OggFLAC__SeekableStreamDecoderPrivate;
/***********************************************************************
@ -720,10 +721,6 @@ FLAC__StreamDecoderReadStatus read_callback_(const OggFLAC__StreamDecoder *decod
(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 = OggFLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
#endif
return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
}
else if(*bytes > 0) {
@ -733,10 +730,6 @@ FLAC__StreamDecoderReadStatus read_callback_(const OggFLAC__StreamDecoder *decod
}
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 = OggFLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
#endif
return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
}
else
@ -762,6 +755,7 @@ FLAC__StreamDecoderWriteStatus write_callback_(const OggFLAC__StreamDecoder *dec
FLAC__ASSERT(frame->header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
seekable_stream_decoder->private_->got_a_frame = true;
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);
@ -843,7 +837,8 @@ FLAC__bool seek_to_absolute_sample_(OggFLAC__SeekableStreamDecoder *decoder, FLA
/* In the first iterations, we will calculate the target byte position
* by the distance from the target sample to left_sample and
* right_sample. After that, we will switch to binary search.
* right_sample (let's call it "proportional search"). After that, we
* will switch to binary search.
*/
unsigned BINARY_SEARCH_AFTER_ITERATION = 2;
@ -864,11 +859,6 @@ FLAC__bool seek_to_absolute_sample_(OggFLAC__SeekableStreamDecoder *decoder, FLA
for( ; ; iteration++) {
if (iteration == 0 || this_frame_sample > target_sample || target_sample - this_frame_sample > LINEAR_SEARCH_WITHIN_SAMPLES) {
if (iteration >= BINARY_SEARCH_AFTER_ITERATION) {
/* sanity check to avoid infinite loop */
if (left_pos == right_pos) {
decoder->protected_->state = OggFLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
pos = (right_pos + left_pos) / 2;
}
else {
@ -878,6 +868,13 @@ FLAC__bool seek_to_absolute_sample_(OggFLAC__SeekableStreamDecoder *decoder, FLA
#else
pos = (FLAC__uint64)((double)(target_sample - left_sample) / (double)(right_sample - left_sample) * (double)(right_pos - left_pos));
#endif
/* @@@ TODO: might want to limit pos to some distance
* before EOF, to make sure we land before the last frame,
* thereby getting a this_fram_sample and so having a better
* estimate. this would also mostly (or totally if we could
* be sure to land before the last frame) avoid the
* end-of-stream case we have to check later.
*/
}
/* physical seek */
@ -894,12 +891,33 @@ FLAC__bool seek_to_absolute_sample_(OggFLAC__SeekableStreamDecoder *decoder, FLA
else
did_a_seek = false;
decoder->private_->got_a_frame = false;
if(!OggFLAC__stream_decoder_process_single(decoder->private_->stream_decoder)) {
decoder->protected_->state = OggFLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
if(!decoder->private_->got_a_frame) {
if(did_a_seek) {
/* this can happen if we seek to a point after the last frame; we drop
* to binary search right away in this case to avoid any wasted
* iterations of proportional search.
*/
right_pos = pos;
BINARY_SEARCH_AFTER_ITERATION = 0;
}
else {
/* this can probably only happen if total_samples is unknown and the
* target_sample is past the end of the stream
*/
decoder->protected_->state = OggFLAC__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 != OggFLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
else if(
decoder->protected_->state != OggFLAC__SEEKABLE_STREAM_DECODER_SEEKING &&
decoder->protected_->state != OggFLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM
) {
break;
}
else {
@ -917,10 +935,20 @@ FLAC__bool seek_to_absolute_sample_(OggFLAC__SeekableStreamDecoder *decoder, FLA
FLAC__ASSERT(this_frame_sample != target_sample);
left_sample = this_frame_sample;
/* sanity check to avoid infinite loop */
if (left_pos == pos) {
decoder->protected_->state = OggFLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
left_pos = pos;
}
else if(this_frame_sample > target_sample) {
right_sample = this_frame_sample;
/* sanity check to avoid infinite loop */
if (right_pos == pos) {
decoder->protected_->state = OggFLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
return false;
}
right_pos = pos;
}
}