diff options
Diffstat (limited to 'libmpdemux/demuxer.c')
-rw-r--r-- | libmpdemux/demuxer.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/libmpdemux/demuxer.c b/libmpdemux/demuxer.c index 7b762346d9..8ff2fc747f 100644 --- a/libmpdemux/demuxer.c +++ b/libmpdemux/demuxer.c @@ -426,6 +426,41 @@ while(len>0){ return bytes; } +/** + * \brief read data until the given 3-byte pattern is encountered, up to maxlen + * \param mem memory to read data into, may be NULL to discard data + * \param maxlen maximum number of bytes to read + * \param read number of bytes actually read + * \param pattern pattern to search for (lowest 8 bits are ignored) + * \return whether pattern was found + */ +int demux_pattern_3(demux_stream_t *ds, unsigned char *mem, int maxlen, + int *read, uint32_t pattern) { + register uint32_t head = 0xffffff00; + register uint32_t pat = pattern & 0xffffff00; + int total_len = 0; + do { + register unsigned char *ds_buf = &ds->buffer[ds->buffer_size]; + int len = ds->buffer_size - ds->buffer_pos; + register long pos = -len; + if (unlikely(pos >= 0)) { // buffer is empty + ds_fill_buffer(ds); + continue; + } + do { + head |= ds_buf[pos]; + head <<= 8; + } while (++pos && head != pat); + len += pos; + if (total_len + len > maxlen) + len = maxlen - total_len; + len = demux_read_data(ds, mem ? &mem[total_len] : NULL, len); + total_len += len; + } while ((head != pat || total_len < 3) && total_len < maxlen && !ds->eof); + if (read) + *read = total_len; + return total_len >= 3 && head == pat; +} void ds_free_packs(demux_stream_t *ds){ demux_packet_t *dp=ds->first; |