mirror of https://github.com/nealey/hdjd.git
157 lines
3.0 KiB
C
157 lines
3.0 KiB
C
#include <stdio.h>
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#include <poll.h>
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#include <sys/select.h>
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#include <alsa/asoundlib.h>
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#include "alsa.h"
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#include "usb.h"
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#include "log.h"
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#include "dump.h"
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static snd_seq_t *snd_handle;
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static int seq_port;
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static snd_midi_event_t *midi_event_parser;
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#define ALSA_BUFSIZE 4096
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int
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alsa_setup(const char *name)
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{
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if (snd_seq_open(&snd_handle, "default", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
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perror("snd_seq_open");
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return -1;
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}
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snd_seq_nonblock(snd_handle, 1);
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snd_seq_set_client_name(snd_handle, name);
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seq_port =
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snd_seq_create_simple_port(snd_handle, name,
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SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_READ |
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SND_SEQ_PORT_CAP_SUBS_WRITE, SND_SEQ_PORT_TYPE_MIDI_GENERIC);
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// Allocate parser object for converting to and from MIDI
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if (snd_midi_event_new(ALSA_BUFSIZE, &midi_event_parser) < 0) {
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fatal("ALSA cannot allocate MIDI event parser");
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}
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return 0;
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}
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void
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alsa_close()
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{
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snd_midi_event_free(midi_event_parser);
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}
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#define MAX_PFDS 20
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int npfd;
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struct pollfd pfd[MAX_PFDS];
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void
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alsa_fd_setup(int *nfds, fd_set *rfds, fd_set *wfds)
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{
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npfd = snd_seq_poll_descriptors_count(snd_handle, POLLIN);
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int i;
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if (npfd > MAX_PFDS) {
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fatal("ALSA wants too many file descriptors");
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}
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snd_seq_poll_descriptors(snd_handle, pfd, npfd, POLLIN);
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for (i = 0; i < npfd; i += 1) {
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if (pfd[i].fd > *nfds) {
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*nfds = pfd[i].fd;
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}
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if (pfd[i].events & POLLIN) {
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FD_SET(pfd[i].fd, rfds);
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}
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}
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}
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void
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alsa_read_ready()
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{
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static snd_seq_event_t *ev;
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for (;;) {
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unsigned char buf[ALSA_BUFSIZE];
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long converted;
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int r;
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r = snd_seq_event_input(snd_handle, &ev);
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if (r == -EAGAIN) {
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break;
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}
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if (r == -ENOSPC) {
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warn("Out of space on input queue");
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}
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converted = snd_midi_event_decode(midi_event_parser, buf, ALSA_BUFSIZE, ev);
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if (converted < 0) {
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warn("Can't decode MIDI event type %d", ev->type);
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} else {
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DUMP_d(converted);
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usb_write(buf, converted);
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}
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}
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}
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void
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alsa_check_fds(fd_set *rfds, fd_set *wfds)
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{
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int i;
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for (i = 0; i < npfd; i += 1) {
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int fd = pfd[i].fd;
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if (FD_ISSET(fd, rfds) || FD_ISSET(fd, wfds)) {
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alsa_read_ready();
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return;
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}
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}
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}
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void
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alsa_write(uint8_t *data, size_t datalen)
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{
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size_t offset = 0;
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for (; datalen > offset;) {
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snd_seq_event_t ev;
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long encoded;
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int r;
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encoded = snd_midi_event_encode(midi_event_parser, data + offset, datalen - offset, &ev);
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if (encoded <= 1) {
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int i;
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warn("Unable to encode MIDI message (%ld < %ld)", encoded, datalen);
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fprintf(stderr, " ");
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for (i = offset; i < datalen; i += 1) {
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fprintf(stderr, "%02x ", data[i]);
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}
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fprintf(stderr, "\n");
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return;
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}
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snd_seq_ev_set_direct(&ev);
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snd_seq_ev_set_source(&ev, seq_port);
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snd_seq_ev_set_subs(&ev);
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r = snd_seq_event_output(snd_handle, &ev);
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if (r < 0) {
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warn("Couldn't write an output event");
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}
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if (r > 200) {
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warn("Output buffer size %d", r);
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}
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offset += encoded;
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}
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snd_seq_drain_output(snd_handle);
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}
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