FLAC__bool seek_to_absolute_sample_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample)
{
- FLAC__uint64 first_frame_offset = decoder->private_->first_frame_offset, lower_bound, upper_bound;
- FLAC__int64 pos = -1, last_pos = -1;
- int i, lower_seek_point = -1, upper_seek_point = -1;
+ FLAC__uint64 first_frame_offset = decoder->private_->first_frame_offset, lower_bound, upper_bound, lower_bound_sample, upper_bound_sample, this_frame_sample;
+ FLAC__int64 pos = -1;
+ int i;
unsigned approx_bytes_per_frame;
- FLAC__uint64 last_frame_sample = FLAC__U64L(0xffffffffffffffff);
- FLAC__bool needs_seek;
+ FLAC__bool needs_seek = true, first_seek = true;
const FLAC__uint64 total_samples = FLAC__stream_decoder_get_total_samples(decoder);
const unsigned min_blocksize = decoder->private_->stream_info.data.stream_info.min_blocksize;
const unsigned max_blocksize = decoder->private_->stream_info.data.stream_info.max_blocksize;
const unsigned max_framesize = decoder->private_->stream_info.data.stream_info.max_framesize;
+ const unsigned min_framesize = decoder->private_->stream_info.data.stream_info.min_framesize;
+ /* take these from the current frame in case they've changed mid-stream */
const unsigned channels = FLAC__stream_decoder_get_channels(decoder);
const unsigned bps = FLAC__stream_decoder_get_bits_per_sample(decoder);
const FLAC__StreamMetadata_SeekTable *seek_table = decoder->private_->has_seek_table? &decoder->private_->seek_table.data.seek_table : 0;
- /* we are just guessing here, but we want to guess high, not low */
+ /* we are just guessing here */
if(max_framesize > 0)
- approx_bytes_per_frame = max_framesize;
+ approx_bytes_per_frame = (max_framesize + min_framesize) / 2 + 1;
/*
* Check if it's a known fixed-blocksize stream. Note that though
* 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.
+ * the first frame and end of the stream.
*/
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);
+ lower_bound_sample = 0;
+ upper_bound = stream_length;
+ upper_bound_sample = total_samples > 0 ? total_samples : target_sample;
/*
* Now we refine the bounds if we have a seektable with
}
if(i >= 0) { /* i.e. we found a suitable seek point... */
lower_bound = first_frame_offset + seek_table->points[i].stream_offset;
- lower_seek_point = i;
+ lower_bound_sample = seek_table->points[i].sample_number;
}
/* find the closest seek point > target_sample, if it exists */
}
if(i < (int)seek_table->num_points) { /* i.e. we found a suitable seek point... */
upper_bound = first_frame_offset + seek_table->points[i].stream_offset;
- upper_seek_point = i;
+ upper_bound_sample = seek_table->points[i].sample_number;
}
}
- /*
- * Now guess at where within those bounds our target
- * sample will be.
- */
- if(seek_table && lower_seek_point >= 0) {
- /* first see if our sample is within a few frames of the lower seekpoint */
- if(seek_table->points[lower_seek_point].sample_number <= target_sample && target_sample < seek_table->points[lower_seek_point].sample_number + (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 - seek_table->points[lower_seek_point].sample_number;
- const FLAC__uint64 range_samples = seek_table->points[upper_seek_point].sample_number - seek_table->points[lower_seek_point].sample_number;
- const FLAC__uint64 range_bytes = (upper_bound>lower_bound? upper_bound - lower_bound - 1 : 0);
+ decoder->private_->target_sample = target_sample;
+ while(1) {
+ /* check if the bounds are still ok */
+ if (lower_bound_sample >= upper_bound_sample || lower_bound > upper_bound) {
+ decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
+ return false;
+ }
+ if(needs_seek) {
#ifndef FLAC__INTEGER_ONLY_LIBRARY
#if defined _MSC_VER || defined __MINGW32__
- /* with MSVC you have to spoon feed it the casting */
- pos = (FLAC__int64)lower_bound + (FLAC__int64)(((FLAC__double)(FLAC__int64)target_offset / (FLAC__double)(FLAC__int64)range_samples) * (FLAC__double)(FLAC__int64)(range_bytes-1)) - approx_bytes_per_frame;
+ /* with VC++ you have to spoon feed it the casting */
+ pos = (FLAC__int64)lower_bound + (FLAC__int64)((FLAC__double)(FLAC__int64)(target_sample - lower_bound_sample) / (FLAC__double)(FLAC__int64)(upper_bound_sample - lower_bound_sample) * (FLAC__double)(FLAC__int64)(upper_bound - lower_bound)) - approx_bytes_per_frame;
#else
- pos = (FLAC__int64)lower_bound + (FLAC__int64)(((FLAC__double)target_offset / (FLAC__double)range_samples) * (FLAC__double)range_bytes) - approx_bytes_per_frame;
+ pos = (FLAC__int64)lower_bound + (FLAC__int64)((FLAC__double)(target_sample - lower_bound_sample) / (FLAC__double)(upper_bound_sample - lower_bound_sample) * (FLAC__double)(upper_bound - lower_bound)) - approx_bytes_per_frame;
#endif
#else
/* a little less accurate: */
- if (range_bytes <= 0xffffffff)
- pos = (FLAC__int64)lower_bound + (FLAC__int64)((target_offset * range_bytes) / range_samples) - approx_bytes_per_frame;
+ if (upper_bound - lower_bound < 0xffffffff)
+ pos = (FLAC__int64)lower_bound + (FLAC__int64)(((target_sample - lower_bound_sample) * (upper_bound - lower_bound)) / (upper_bound_sample - lower_bound_sample)) - approx_bytes_per_frame;
else /* @@@ WATCHOUT, ~2TB limit */
- pos = (FLAC__int64)lower_bound + (FLAC__int64)(((target_offset>>8) * (range_bytes>>8)) / (range_samples>>16)) - 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) {
- /*
- * For max accuracy we should be using
- * (stream_length-first_frame_offset-1) in the divisor, but the
- * difference is trivial and (stream_length-first_frame_offset)
- * has no chance of underflow.
- */
-#ifndef FLAC__INTEGER_ONLY_LIBRARY
-#if defined _MSC_VER || defined __MINGW32__
- /* with VC++ you have to spoon feed it the casting */
- pos = (FLAC__int64)first_frame_offset + (FLAC__int64)(((FLAC__double)(FLAC__int64)target_sample / (FLAC__double)(FLAC__int64)total_samples) * (FLAC__double)(FLAC__int64)(stream_length-first_frame_offset)) - approx_bytes_per_frame;
-#else
- pos = (FLAC__int64)first_frame_offset + (FLAC__int64)(((FLAC__double)target_sample / (FLAC__double)total_samples) * (FLAC__double)(stream_length-first_frame_offset)) - approx_bytes_per_frame;
+ pos = (FLAC__int64)lower_bound + (FLAC__int64)((((target_sample - lower_bound_sample)>>8) * ((upper_bound - lower_bound)>>8)) / ((upper_bound_sample - lower_bound_sample)>>16)) - approx_bytes_per_frame;
#endif
-#else
- /* a little less accurate: */
- if (stream_length < 0xffffffff)
- pos = (FLAC__int64)first_frame_offset + (FLAC__int64)((target_sample * (stream_length-first_frame_offset)) / total_samples) - approx_bytes_per_frame;
- else /* @@@ WATCHOUT, ~2TB limit */
- pos = (FLAC__int64)first_frame_offset + (FLAC__int64)(((target_sample>>8) * ((stream_length-first_frame_offset)>>8)) / (total_samples>>16)) - 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__STREAM_DECODER_TELL_STATUS_OK) {
- decoder->protected_->state = FLAC__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(pos >= (FLAC__int64)upper_bound)
+ pos = (FLAC__int64)upper_bound - 1;
+ if(pos < (FLAC__int64)lower_bound)
+ pos = (FLAC__int64)lower_bound;
if(decoder->private_->seek_callback(decoder, (FLAC__uint64)pos, decoder->private_->client_data) != FLAC__STREAM_DECODER_SEEK_STATUS_OK) {
decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
return false;
if(!decoder->private_->is_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;
+ this_frame_sample = decoder->private_->last_frame.header.number.sample_number;
+
+ if (!decoder->private_->samples_decoded || (this_frame_sample + decoder->private_->last_frame.header.blocksize >= upper_bound_sample && !first_seek)) {
+ if (pos == (FLAC__int64)lower_bound || !needs_seek) {
+ decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
+ return false;
}
- 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__STREAM_DECODER_TELL_STATUS_OK) {
- decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
- return false;
- }
- last_pos = pos;
- pos = (FLAC__int64)upos;
- pos -= FLAC__stream_decoder_get_input_bytes_unconsumed(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__STREAM_DECODER_SEEK_ERROR;
- return false;
- }
- }
+ /* our last move backwards wasn't big enough, try again */
+ approx_bytes_per_frame *= 2;
+ continue;
+ }
+ /* allow one seek over upper bound, required for streams with unknown total_samples */
+ first_seek = false;
+
+ /* make sure we are not seeking in corrupted stream */
+ if (this_frame_sample < lower_bound_sample) {
+ decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
+ return false;
+ }
+
+ FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
+
+ approx_bytes_per_frame = decoder->private_->last_frame.header.blocksize * channels * bps/8 + 64;
+
+ /* we need to narrow the search */
+ if(target_sample < this_frame_sample) {
+ upper_bound_sample = this_frame_sample + decoder->private_->last_frame.header.blocksize;
+ if(!FLAC__stream_decoder_get_decode_position(decoder, &upper_bound)) {
+ decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
+ return false;
+ }
+ }
+ else {
+ /* target_sample >= this_frame_sample + this frame's blocksize */
+
+ /* we are close, continue in decoding next frames */
+ if(target_sample < this_frame_sample + 4 * decoder->private_->last_frame.header.blocksize)
+ needs_seek = false;
+
+ lower_bound_sample = this_frame_sample + decoder->private_->last_frame.header.blocksize;
+ if(!FLAC__stream_decoder_get_decode_position(decoder, &lower_bound)) {
+ decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
+ return false;
}
- if(pos < (FLAC__int64)lower_bound)
- pos = (FLAC__int64)lower_bound;
- last_frame_sample = this_frame_sample;
}
}
projects / platform / upstream / flac.git / commitdiff