jack2/example-clients/midiseq.c

/*
    Copyright (C) 2004 Ian Esten

    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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <jack/jack.h>
#include <jack/midiport.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>

jack_client_t *client;
jack_port_t *output_port;

unsigned char* note_frqs;
jack_nframes_t* note_starts;
jack_nframes_t* note_lengths;
jack_nframes_t num_notes;
jack_nframes_t loop_nsamp;
jack_nframes_t loop_index;

static void signal_handler(int sig)
{
	jack_client_close(client);
	fprintf(stderr, "signal received, exiting ...\n");
	exit(0);
}

static void usage()
{
	fprintf(stderr, "usage: jack_midiseq name nsamp [startindex note nsamp] ...... [startindex note nsamp]\n");
	fprintf(stderr, "eg: jack_midiseq Sequencer 24000 0 60 8000 12000 63 8000\n");
	fprintf(stderr, "will play a 1/2 sec loop (if srate is 48khz) with a c4 note at the start of the loop\n");
	fprintf(stderr, "that lasts for 12000 samples, then a d4# that starts at 1/4 sec that lasts for 800 samples\n");
}

static int process(jack_nframes_t nframes, void *arg)
{
    int i,j;
    void* port_buf = jack_port_get_buffer(output_port, nframes);
    unsigned char* buffer;
    jack_midi_clear_buffer(port_buf);
    /*memset(buffer, 0, nframes*sizeof(jack_default_audio_sample_t));*/

    for (i = 0; i < nframes; i++) {
        for (j = 0; j < num_notes; j++) {
            if (note_starts[j] == loop_index) {
                if ((buffer = jack_midi_event_reserve(port_buf, i, 3))) {
                    /* printf("wrote a note on, port buffer = 0x%x, event buffer = 0x%x\n", port_buf, buffer); */
                    buffer[2] = 64;		/* velocity */
                    buffer[1] = note_frqs[j];
                    buffer[0] = 0x90;	/* note on */
                }
            } else if (note_starts[j] + note_lengths[j] == loop_index) {
                if ((buffer = jack_midi_event_reserve(port_buf, i, 3))) {
                    /* printf("wrote a note off, port buffer = 0x%x, event buffer = 0x%x\n", port_buf, buffer); */
                    buffer[2] = 64;		/* velocity */
                    buffer[1] = note_frqs[j];
                    buffer[0] = 0x80;	/* note off */
                }
            }
        }
        loop_index = loop_index+1 >= loop_nsamp ? 0 : loop_index+1;
    }
    return 0;
}

int main(int narg, char **args)
{
	int i;
	if ((narg<6) || ((narg-3)%3 != 0)) {
		usage();
		exit(1);
	}
	if ((client = jack_client_open (args[1], JackNullOption, NULL)) == 0) {
		fprintf (stderr, "JACK server not running?\n");
		return 1;
	}
	jack_set_process_callback (client, process, 0);
	output_port = jack_port_register (client, "out", JACK_DEFAULT_MIDI_TYPE, JackPortIsOutput, 0);
	loop_index = 0;
	num_notes = (narg - 3)/3;
	note_frqs = malloc(num_notes*sizeof(unsigned char));
	note_starts = malloc(num_notes*sizeof(jack_nframes_t));
	note_lengths = malloc(num_notes*sizeof(jack_nframes_t));
	loop_nsamp = atoi(args[2]);
	for (i = 0; i < num_notes; i++) {
		note_starts[i] = atoi(args[3 + 3*i]);
		note_frqs[i] = atoi(args[4 + 3*i]);
		note_lengths[i] = atoi(args[5 + 3*i]);
	}

	if (jack_activate(client)) {
		fprintf (stderr, "cannot activate client");
		return 1;
	}

	/* install a signal handler to properly quits jack client */
#ifndef WIN32
	signal(SIGQUIT, signal_handler);
	signal(SIGHUP, signal_handler);
#endif
	signal(SIGTERM, signal_handler);
	signal(SIGINT, signal_handler);

	/* run until interrupted */
	while (1) {
#ifdef WIN32
		Sleep(1*1000);
#else
		sleep(1);
#endif
	};

    jack_client_close(client);
	exit (0);
}