/*
 * set the sample rate of the audio device
 */

#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/soundcard.h>

#define TRUE 1
#define FALSE 0

extern int errno;

int verbose = FALSE;
char *progname;		/* Program name */

void usage()
{
  fprintf(stderr,
	  "Usage: %s -d audio_device_name -r rate\n", progname);
  exit(0);
}

int 
main(int argc, char *argv[])
{
  extern char *optarg;		/* for the getopt() system call */
  extern int optind, opterr, optopt;
  int errflg=FALSE;		/* set if there is a command line error */
  int c;

  int dspFD;
  int ioctlParam;
  int rate=44100;		/* default is 44100 */

  char *dspname;
  char default_dspname[]="/dev/sound/dsp";

  dspname=default_dspname;

  progname = argv[0];

  /*
   * Decode argument list
   */
  while ((c = getopt(argc, argv, "d:hr:v")) != EOF)
    switch (c) {
    case 'v':
      verbose = TRUE;
      break;

    case 'h':
    case '?':
      usage();
      break;

    case 'd':
      if (verbose)
	fprintf(stdout, "selected audio device is %s\n",optarg);

      dspname=optarg;
      break;

    case ':':        /* -d or -r without arguments */
      fprintf(stderr, "Option -%c requires an argument\n", optopt);
      errflg++;
      break;

    case 'r':
      sscanf(optarg, "%d", &rate);

      if (verbose)
	fprintf(stdout, "selected audio rate is %d\n", rate);
      break;

    }
  
  if (errflg)
    usage();

  if ((dspFD = open(dspname, O_RDWR)) < 0) {
    perror(dspname);
    exit(1);
  }

  ioctlParam = rate;
  if( ioctl( dspFD, SNDCTL_DSP_SPEED, &ioctlParam ) == -1 )
    {
      perror("SNDCTL_DSP_SPEED");
      exit(-1);
    }

  if (verbose && (ioctlParam != rate) ) {
    fprintf(stdout, "Failed to set sample rate to %d\n", rate);
  }

  if (verbose)
    fprintf(stderr, "actual speed is %d\n", ioctlParam);

  close(dspFD);
}