/**
* Locates, basing on track->next_event_offset, the next event data in track->buffer,
* interprets it, allocates smf_event_t and fills it properly. Returns smf_event_t
* or NULL, if there was an error. Allocating event means adding it to the track;
* see smf_event_new().
*/
static smf_event_t *
parse_next_event(smf_track_t *track)
{
uint32_t etime = 0;
uint32_t len;
size_t buffer_length;
unsigned char *c, *start;
smf_event_t *event = smf_event_new();
if (event == NULL)
goto error;
c = start = (unsigned char *)track->file_buffer + track->next_event_offset;
assert(track->file_buffer != NULL);
assert(track->file_buffer_length > 0);
assert(track->next_event_offset > 0);
buffer_length = track->file_buffer_length - track->next_event_offset;
/* if there was no meta-EOT event, buffer_length can be zero. This is
an error in the SMF file, but it shouldn't be treated as fatal.
*/
if (buffer_length == 0) {
g_warning ("SMF warning: expected EOT at end of track, but none found");
goto error;
}
/* First, extract time offset from previous event. */
if (smf_extract_vlq(c, buffer_length, &etime, &len)) {
goto error;
}
c += len;
buffer_length -= len;
if (buffer_length <= 0)
goto error;
/* Now, extract the actual event. */
if (extract_midi_event(c, buffer_length, event, &len, track->last_status)) {
goto error;
}
c += len;
buffer_length -= len;
track->last_status = event->midi_buffer[0];
track->next_event_offset += c - start;
smf_track_add_event_delta_pulses(track, event, etime);
return (event);
error:
if (event != NULL)
smf_event_delete(event);
return (NULL);
}
/**
* Add End Of Track metaevent. Using it is optional, libsmf will automatically
* add EOT to the tracks during smf_save, with delta_pulses 0. If you try to add EOT
* in the middle of the track, it will fail and nonzero value will be returned.
* If you try to add EOT after another EOT event, it will be added, but the existing
* EOT event will be removed.
*
* \return 0 if everything went ok, nonzero otherwise.
*/
int
smf_track_add_eot_delta_pulses(smf_track_t *track, int delta)
{
smf_event_t *event;
event = smf_event_new_from_bytes(0xFF, 0x2F, 0x00);
if (event == NULL)
return (-1);
smf_track_add_event_delta_pulses(track, event, delta);
return (0);
}
