/*
 * parrot.c
 * From "Linux Multimedia Guide"
 * by Jeff Tranter
 * Program to illustrate /dev/dsp device
 * Records several seconds of sound, then echoes it back.
 * Runs until Control-C is pressed.
 */


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

#define LENGTH 3		/* how many seconds of speech to store */
#define RATE 44100		/* the sampling rate */
#define SIZE 8			/* sample size: 8 or 16 bits */
#define CHANNELS 1		/* 1 = mono 2 = stereo */

/* this buffer holds the digitized audio */
unsigned char buf[LENGTH * RATE * SIZE * CHANNELS / 8];

int
main ()
{
  int fd;			/* sound device file descriptor */
  int arg;			/* argument for ioctl calls */
  int status;			/* return status of system calls */

  /* open sound device */
  fd = open ("/dev/dsp", O_RDWR);
  if (fd < 0)
    {
      perror ("open of /dev/dsp failed");
      exit (1);
    }

  /* set sampling parameters */
  arg = SIZE;			/* sample size */
  status = ioctl (fd, SOUND_PCM_WRITE_BITS, &arg);
  if (status == -1)
    perror ("SOUND_PCM_WRITE_BITS ioctl failed");
  if (arg != SIZE)
    perror ("unable to set sample size");

  arg = CHANNELS;		/* mono or stereo */
  status = ioctl (fd, SOUND_PCM_WRITE_CHANNELS, &arg);
  if (status == -1)
    perror ("SOUND_PCM_WRITE_CHANNELS ioctl failed");
  if (arg != CHANNELS)
    perror ("unable to set number of channels");

  arg = RATE;			/* sampling rate */
  status = ioctl (fd, SOUND_PCM_WRITE_RATE, &arg);
  if (status == -1)
    perror ("SOUND_PCM_WRITE_WRITE ioctl failed");

  while (1)
    {				/* loop until Control-C */
      printf ("Say something:\n");
      status = read (fd, buf, sizeof (buf));	/* record some sound */
      if (status != sizeof (buf))
	perror ("read wrong number of bytes");
      printf ("You said:\n");
      status = write (fd, buf, sizeof (buf));	/* play it back */
      if (status != sizeof (buf))
	perror ("wrote wrong number of bytes");
      /* wait for playback to complete before recording again */
      status = ioctl (fd, SOUND_PCM_SYNC, 0);
      if (status == -1)
	perror ("SOUND_PCM_SYNC ioctl failed");
    }
}