sintonia/library/ecasound-2.7.2/libecasound/midiio-aseq.cpp

232 lines
6.7 KiB
C++

// ------------------------------------------------------------------------
// midiio-aseq.cpp: Input and output of MIDI streams using
// ALSA Sequencer
// Copyright (C) 2005 Pedro Lopez-Cabanillas
// Copyright (C) 2005 Kai Vehmanen
//
// Attributes:
// eca-style-version: 3
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// ------------------------------------------------------------------------
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef ECA_COMPILE_ALSA
#include <cstdio>
#include <fcntl.h>
#include <unistd.h>
#include "midiio-aseq.h"
#include "eca-logger.h"
MIDI_IO_ASEQ::MIDI_IO_ASEQ(const std::string& name) { label("alsaseq"); device_name_rep = name; }
MIDI_IO_ASEQ::~MIDI_IO_ASEQ(void) { if (is_open()) close(); }
void MIDI_IO_ASEQ::open(void)
{
int open_flags = 0, port_flags = 0;
switch(io_mode()) {
case io_read:
{
open_flags = SND_SEQ_OPEN_INPUT;
port_flags = SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE;
break;
}
case io_write:
{
open_flags = SND_SEQ_OPEN_OUTPUT;
port_flags = SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ;
break;
}
case io_readwrite:
{
open_flags = SND_SEQ_OPEN_DUPLEX;
port_flags = SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE |
SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ;
break;
}
}
ECA_LOG_MSG(ECA_LOGGER::system_objects, "Opening ALSA sequencer");
int err = snd_seq_open(&seq_handle_repp, "default", open_flags, SND_SEQ_NONBLOCK);
if (err < 0) {
toggle_open_state(false);
}
else {
toggle_open_state(true);
}
// Set client name.
snd_seq_set_client_name(seq_handle_repp, "ecasound");
// Create a simple port
port_rep = snd_seq_create_simple_port( seq_handle_repp, "ecasound",
port_flags,
SND_SEQ_PORT_TYPE_MIDI_GENERIC);
// Parse the device name, and connect it to the port when successful
snd_seq_addr_t subs;
err = snd_seq_parse_address(seq_handle_repp, &subs, device_name_rep.c_str());
if( err == 0) {
switch(io_mode()) {
case io_read:
snd_seq_connect_to(seq_handle_repp, port_rep, subs.client, subs.port);
break;
case io_write:
snd_seq_connect_from(seq_handle_repp, port_rep, subs.client, subs.port);
break;
case io_readwrite:
snd_seq_connect_to(seq_handle_repp, port_rep, subs.client, subs.port);
snd_seq_connect_from(seq_handle_repp, port_rep, subs.client, subs.port);
break;
}
}
// Create the encoder/decoder instance
err = snd_midi_event_new( buffer_size_rep = 16, &coder_repp );
// ...
finished_rep = false;
}
void MIDI_IO_ASEQ::close(void)
{
// Release the xxcoder instance
snd_midi_event_free( coder_repp );
// Delete the port
snd_seq_delete_port( seq_handle_repp, port_rep );
// Close the sequencer client
snd_seq_close( seq_handle_repp );
toggle_open_state(false);
}
int MIDI_IO_ASEQ::poll_descriptor(void) const
{
struct pollfd *pfds;
int npfds;
npfds = snd_seq_poll_descriptors_count(seq_handle_repp, POLLIN|POLLOUT);
pfds = reinterpret_cast<struct pollfd*>(alloca(sizeof(*pfds) * npfds));
snd_seq_poll_descriptors(seq_handle_repp, pfds, npfds, POLLIN|POLLOUT);
return pfds->fd;
}
bool MIDI_IO_ASEQ::finished(void) const { return finished_rep; }
long int MIDI_IO_ASEQ::read_bytes(void* target_buffer, long int bytes)
{
snd_seq_event_t *event;
int err = 0, position = 0;
if ( bytes > buffer_size_rep ) {
snd_midi_event_resize_buffer ( coder_repp, bytes );
buffer_size_rep = bytes;
}
while (true) {
if (snd_seq_event_input_pending(seq_handle_repp, 1) == 0) {
return position;
}
err = snd_seq_event_input(seq_handle_repp, &event);
if (err < 0) {
break;
}
if ( event->type == SND_SEQ_EVENT_CONTROLLER ||
event->type == SND_SEQ_EVENT_CONTROL14 ||
event->type == SND_SEQ_EVENT_NONREGPARAM ||
event->type == SND_SEQ_EVENT_REGPARAM ||
event->type == SND_SEQ_EVENT_SYSEX ) {
err = snd_midi_event_decode( coder_repp,
((unsigned char *)target_buffer) + position,
bytes - position,
event );
if (err < 0) {
break;
}
position += err;
if ( position >= bytes) return position;
}
}
finished_rep = true;
ECA_LOG_MSG(ECA_LOGGER::system_objects,
std::string("error while reading from ALSA sequencer: ") + snd_strerror(err));
return err;
}
long int MIDI_IO_ASEQ::write_bytes(void* target_buffer, long int bytes) {
snd_seq_event_t ev;
int err = 0;
if ( bytes > buffer_size_rep ) {
snd_midi_event_resize_buffer ( coder_repp, bytes );
buffer_size_rep = bytes;
}
snd_seq_ev_clear(&ev);
snd_seq_ev_set_source(&ev, port_rep);
snd_seq_ev_set_subs(&ev);
snd_seq_ev_set_direct(&ev);
err = snd_midi_event_encode( coder_repp,
(unsigned char *)target_buffer,
bytes, &ev );
if (err == bytes) {
snd_seq_event_output(seq_handle_repp, &ev);
snd_seq_drain_output(seq_handle_repp);
return err;
}
finished_rep = true;
return err;
}
void MIDI_IO_ASEQ::set_parameter(int param,
std::string value)
{
switch (param) {
case 1:
label(value);
break;
case 2:
device_name_rep = value;
break;
}
}
std::string MIDI_IO_ASEQ::get_parameter(int param) const
{
switch (param) {
case 1:
return label();
case 2:
return device_name_rep;
}
return "";
}
/**
* FIXME: This is an alternative to using the poll_descriptor()
* interface...
*/
bool MIDI_IO_ASEQ::pending_messages(unsigned long timeout) const
{
struct pollfd *pfds;
int result = 0;
int npfds = snd_seq_poll_descriptors_count(seq_handle_repp, POLLIN);
pfds = (struct pollfd *)alloca(sizeof(*pfds) * npfds);
snd_seq_poll_descriptors(seq_handle_repp, pfds, npfds, POLLIN);
result = poll(pfds, npfds, timeout);
return (result > 0);
}
#endif /* COMPILE_ALSA */