diff options
| -rw-r--r-- | apps/codecs/libmusepack/mpc_demux.c | 45 |
1 files changed, 27 insertions, 18 deletions
diff --git a/apps/codecs/libmusepack/mpc_demux.c b/apps/codecs/libmusepack/mpc_demux.c index 244ef25..e74e420 100644 --- a/apps/codecs/libmusepack/mpc_demux.c +++ b/apps/codecs/libmusepack/mpc_demux.c @@ -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; - - // FIXME : do not flush the buffer if fpos is in the current buffer - - next_pos = fpos >> 3; - 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)); - - 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); - 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); + // 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; + + // 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; + 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, DEMUX_BUFFER_SIZE, MPC_BUFFER_SWAP); + else + mpc_demux_fill(d, DEMUX_BUFFER_SIZE, 0); + d->bits_reader.buff += buf_fpos >> 3; + d->bits_reader.count = 8 - (buf_fpos & 7); + } } /** |