mpeg2_state_t mpeg2_parse (mpeg2dec_t * mpeg2dec)
{
int size_buffer, size_chunk, copied;
if (mpeg2dec->action) {
mpeg2_state_t state;
state = mpeg2dec->action (mpeg2dec);
if ((int)state > (int)STATE_INTERNAL_NORETURN)
return state;
}
while (1) {
while ((unsigned) (mpeg2dec->code - mpeg2dec->first_decode_slice) <
mpeg2dec->nb_decode_slices) {
size_buffer = mpeg2dec->buf_end - mpeg2dec->buf_start;
size_chunk = (mpeg2dec->chunk_buffer + BUFFER_SIZE -
mpeg2dec->chunk_ptr);
if (size_buffer <= size_chunk) {
copied = copy_chunk (mpeg2dec, size_buffer);
if (!copied) {
mpeg2dec->bytes_since_tag += size_buffer;
mpeg2dec->chunk_ptr += size_buffer;
return STATE_BUFFER;
}
} else {
copied = copy_chunk (mpeg2dec, size_chunk);
if (!copied) {
/* filled the chunk buffer without finding a start code */
mpeg2dec->bytes_since_tag += size_chunk;
mpeg2dec->action = seek_chunk;
return STATE_INVALID;
}
}
mpeg2dec->bytes_since_tag += copied;
mpeg2_slice (&(mpeg2dec->decoder), mpeg2dec->code,
mpeg2dec->chunk_start);
mpeg2dec->code = mpeg2dec->buf_start[-1];
mpeg2dec->chunk_ptr = mpeg2dec->chunk_start;
}
if ((unsigned) (mpeg2dec->code - 1) >= 0xb0 - 1)
break;
if (seek_chunk (mpeg2dec) == STATE_BUFFER)
return STATE_BUFFER;
}
mpeg2dec->action = mpeg2_seek_header;
switch (mpeg2dec->code) {
case 0x00:
return mpeg2dec->state;
case 0xb3:
case 0xb7:
case 0xb8:
return (mpeg2dec->state == STATE_SLICE) ? STATE_SLICE : STATE_INVALID;
default:
mpeg2dec->action = seek_chunk;
return STATE_INVALID;
}
}
mpeg2_state_t mpeg2_seek_header (mpeg2dec_t * mpeg2dec)
{
while (!(mpeg2dec->code == 0xb3 ||
((mpeg2dec->code == 0xb7 || mpeg2dec->code == 0xb8 ||
!mpeg2dec->code) && mpeg2dec->sequence.width != (unsigned)-1)))
if (seek_chunk (mpeg2dec) == STATE_BUFFER)
return STATE_BUFFER;
mpeg2dec->chunk_start = mpeg2dec->chunk_ptr = mpeg2dec->chunk_buffer;
mpeg2dec->user_data_len = 0;
return ((mpeg2dec->code == 0xb7) ?
mpeg2_header_end (mpeg2dec) : mpeg2_parse_header (mpeg2dec));
}
mpeg2_state_t mpeg2_seek_header (mpeg2dec_t * mpeg2dec)
{
while (mpeg2dec->code != 0xb3 &&
((mpeg2dec->code != 0xb7 && mpeg2dec->code != 0xb8 &&
mpeg2dec->code) || mpeg2dec->sequence.width == (unsigned)-1))
if (seek_chunk (mpeg2dec) == STATE_BUFFER)
return STATE_BUFFER;
mpeg2dec->chunk_start = mpeg2dec->chunk_ptr = mpeg2dec->chunk_buffer;
mpeg2dec->user_data_len = 0;
return (mpeg2dec->code ? mpeg2_parse_header (mpeg2dec) :
mpeg2_header_picture_start (mpeg2dec));
}
