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Fix FS#11261 (slow seek forward in mpc files). Since the introduction of the sv8 library mpc did not use efficient buffering when seeking forward. With this change the implementation will not flush the buffer on each frame but will keep the already buffered data as long as possible.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26032 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andree Buschmann 2010-05-14 22:06:28 +00:00
parent 7036a10126
commit db42781ca8
1 changed files with 26 additions and 17 deletions
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29
apps/codecs/libmusepack/mpc_demux.c
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@ -120,24 +120,33 @@ mpc_demux_fill(mpc_demux * d, mpc_uint32_t min_bytes, int flags)
*/
static void
mpc_demux_seek(mpc_demux * d, mpc_seek_t fpos, mpc_uint32_t min_bytes) {
mpc_seek_t next_pos;
mpc_int_t bit_offset;
// d->bits_reader.buff - d->buffer = current byte position within buffer
// d->bytes_total = buffer is filled with bytes_total bytes
// fpos = desired file position in bit (not byte)
// buf_fpos = desired byte position within buffer
mpc_seek_t next_pos = fpos>>3;
mpc_int_t buf_fpos = next_pos - d->r->tell(d->r) + d->bytes_total;
// FIXME : do not flush the buffer if fpos is in the current buffer
next_pos = fpos >> 3;
// is desired byte position within lower and upper boundaries of buffer?
if (buf_fpos >= 0 && buf_fpos + min_bytes <= DEMUX_BUFFER_SIZE) {
// desired bytes are available in current buffer
d->bits_reader.buff += buf_fpos - (d->bits_reader.buff - d->buffer);
d->bits_reader.count = 8 - (fpos & 7);
} else {
// buffer needs to be refilled
if (d->si.stream_version == 7)
next_pos = ((next_pos - d->si.header_position) & (-1 << 2)) + d->si.header_position;
bit_offset = (int) (fpos - (next_pos << 3));
buf_fpos = fpos - (next_pos << 3);
d->r->seek(d->r, (mpc_int32_t) next_pos);
mpc_demux_clear_buff(d);
if (d->si.stream_version == 7)
mpc_demux_fill(d, (min_bytes + ((bit_offset + 7) >> 3) + 3) & (~3), MPC_BUFFER_SWAP);
mpc_demux_fill(d, DEMUX_BUFFER_SIZE, MPC_BUFFER_SWAP);
else
mpc_demux_fill(d, min_bytes + ((bit_offset + 7) >> 3), 0);
d->bits_reader.buff += bit_offset >> 3;
d->bits_reader.count = 8 - (bit_offset & 7);
mpc_demux_fill(d, DEMUX_BUFFER_SIZE, 0);
d->bits_reader.buff += buf_fpos >> 3;
d->bits_reader.count = 8 - (buf_fpos & 7);
}
}
/**