static void
jack_audio_port_mixdown (jack_port_t *port, jack_nframes_t nframes)
{
JSList *node;
jack_port_t *input;
#ifndef ARCH_X86
jack_nframes_t n;
jack_default_audio_sample_t *dst, *src;
#endif
jack_default_audio_sample_t *buffer;
/* by the time we've called this, we've already established
the existence of more than one connection to this input
port and allocated a mix_buffer.
*/
/* no need to take connection lock, since this is called
from the process() callback, and the jack server
ensures that no changes to connections happen
during this time.
*/
node = port->connections;
input = (jack_port_t*)node->data;
buffer = port->mix_buffer;
#ifndef USE_DYNSIMD
memcpy (buffer, jack_output_port_buffer (input),
sizeof(jack_default_audio_sample_t) * nframes);
#else /* USE_DYNSIMD */
opt_copy (buffer, jack_output_port_buffer (input), nframes);
#endif /* USE_DYNSIMD */
for (node = jack_slist_next (node); node;
node = jack_slist_next (node)) {
input = (jack_port_t*)node->data;
#ifndef USE_DYNSIMD
n = nframes;
dst = buffer;
src = jack_output_port_buffer (input);
while (n--)
*dst++ += *src++;
#else /* USE_DYNSIMD */
opt_mix (buffer, jack_output_port_buffer (input), nframes);
#endif /* USE_DYNSIMD */
}
}
void *
jack_port_get_buffer (jack_port_t *port, jack_nframes_t nframes)
{
JSList *node, *next;
/* Output port. The buffer was assigned by the engine
when the port was registered.
*/
if (port->shared->flags & JackPortIsOutput) {
if (port->tied) {
return jack_port_get_buffer (port->tied, nframes);
}
if (port->client_segment_base == NULL || *port->client_segment_base == MAP_FAILED) {
return NULL;
}
return jack_output_port_buffer (port);
}
/* Input port. Since this can only be called from the
process() callback, and since no connections can be
made/broken during this phase (enforced by the jack
server), there is no need to take the connection lock here
*/
if ((node = port->connections) == NULL) {
if (port->client_segment_base == NULL || *port->client_segment_base == MAP_FAILED) {
return NULL;
}
/* no connections; return a zero-filled buffer */
return (void *) (*(port->client_segment_base) + port->type_info->zero_buffer_offset);
}
if ((next = jack_slist_next (node)) == NULL) {
/* one connection: use zero-copy mode - just pass
the buffer of the connected (output) port.
*/
return jack_port_get_buffer (((jack_port_t *) node->data),
nframes);
}
/* Multiple connections. Use a local buffer and mix the
incoming data into that buffer. We have already
established the existence of a mixdown function during the
connection process.
*/
if (port->mix_buffer == NULL) {
jack_error( "internal jack error: mix_buffer not allocated" );
return NULL;
}
port->fptr.mixdown (port, nframes);
return (void *) port->mix_buffer;
}
