mixer.c

/*
 *    This is an example of a mixer program for Linux
 *
 *      updated 1/1/93 to add stereo, level query, broken
 *              devmask kludge - cmetz@thor.tjhsst.edu 
 *
 *      slightly modified by in3otd@qsl.net
 *
 * (C) Craig Metz and Hannu Savolainen 1993.
 *
 * You may do anything you wish with this program.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>

void usage(void);
void print_recsrc(void);

char *names[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_NAMES;

int devmask = 0, recmask = 0, recsrc = 0;

void usage(void)
{
  int i, n = 0;
  printf("Usage: mixer { ");

  for (i = 0; i < SOUND_MIXER_NRDEVICES; i++)
    if ((1 << i) & devmask) {
      if (n)
	putchar('|');
      printf(names[i]);
      n = 1;
    }
  printf(" } <value>\n  or   mixer { +rec|-rec } <devicename>\n");
  exit(1);
}

void print_recsrc(void)
{
  int i, n = 0;
  fprintf(stderr, "Recording source: ");

  for (i = 0; i < SOUND_MIXER_NRDEVICES; i++)
    if ((1 << i) & recsrc) {
      if (n)
	fprintf(stderr, ", ");
      fprintf(stderr, names[i]);
      n = 1;
    }
  fprintf(stderr, "\n");
}

int main(int argc, char *argv[])
{
  int foo, bar, baz, dev;

  char name[30] = "/dev/mixer";

  if (!strcmp(argv[0], "mixer0"))
    strcpy(name, "/dev/mixer");
  else if (!strcmp(argv[0], "mixer1"))
    strcpy(name, "/dev/mixer1");
  else if (!strcmp(argv[0], "mixer2"))
    strcpy(name, "/dev/mixer2");
  else if (!strcmp(argv[0], "mixer3"))
    strcpy(name, "/dev/mixer3");
  else if (!strcmp(argv[0], "mixer4"))
    strcpy(name, "/dev/mixer4");
  else if (!strcmp(argv[0], "mixer5"))
    strcpy(name, "/dev/mixer5");

  if ((baz = open(name, O_RDWR)) < 0) {
    perror(name);
    exit(1);
  }
  if (ioctl(baz, SOUND_MIXER_READ_DEVMASK, &devmask) == -1) {
    perror("SOUND_MIXER_READ_DEVMASK");
    exit(-1);
  }
  if (ioctl(baz, SOUND_MIXER_READ_RECMASK, &recmask) == -1) {
    perror("SOUND_MIXER_READ_RECMASK");
    exit(-1);
  }
  if (ioctl(baz, SOUND_MIXER_READ_RECSRC, &recsrc) == -1) {
    perror("SOUND_MIXER_READ_RECSRC");
    exit(-1);
  }
  switch (argc) {
  case 3:
    bar = 1;
    break;
  case 2:
    bar = 0;
    break;
  default:
    usage();
  }

  for (foo = 0; foo < SOUND_MIXER_NRDEVICES && strcmp(names[foo], argv[1]); foo++);

  if (foo >= SOUND_MIXER_NRDEVICES) {

    if (!strcmp("+rec", argv[1]) || !strcmp("-rec", argv[1])) {
      for (dev = 0; dev < SOUND_MIXER_NRDEVICES && strcmp(names[dev], argv[2]); dev++);
      if (dev >= SOUND_MIXER_NRDEVICES)
	usage();

      if (!((1 << dev) & recmask)) {
	fprintf(stderr, "Invalid recording source %s\n", argv[2]);
	exit(-1);
      }
      if (argv[1][0] == '+')
	recsrc |= (1 << dev);
      else
	recsrc &= ~(1 << dev);

      if (ioctl(baz, SOUND_MIXER_WRITE_RECSRC, &recsrc) == -1) {
	perror("SOUND_MIXER_WRITE_RECSRC");
	exit(-1);
      }
      print_recsrc();

    } else
      usage();
  } else {
    if (bar) {
      if (strchr(argv[2], ':') == NULL) {
	sscanf(argv[2], "%d", &bar);
	dev = bar;
      } else
	sscanf(argv[2], "%d:%d", &bar, &dev);

      if (bar < 0)
	bar = 0;
      if (dev < 0)
	dev = 0;
      if (bar > 100)
	bar = 100;
      if (dev > 100)
	dev = 100;

      printf("Setting the mixer %s to %d:%d.\n", names[foo], bar, dev);

      bar |= dev << 8;
      if (ioctl(baz, MIXER_WRITE(foo), &bar) == -1)
	perror("WRITE_MIXER");
      return (0);
    } else {
      if (ioctl(baz, MIXER_READ(foo), &bar) == -1)
	perror("MIXER_READ");
      printf("The mixer %s is currently set to %d:%d.\n", names[foo], bar & 0x7f, (bar >> 8) & 0x7f);
    }
  }

  close(baz);
  return (0);
}