/**
 * recording.c
 * Copyright (C) 2008 Markus Broeker
 *
 * 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 8000               /* 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 argc, char **argv)
{
    int fd;                     /* sound device file descriptor */
    int arg;                    /* argument for ioctl calls */
    int status;                 /* return status of system calls */

    /*
     * open sound device
     */

    if (argc != 2) {
        printf ("Usage: %s <device>\n", argv[0]);
        printf ("Example: %s /dev/dsp\n", argv[0]);
        printf ("Example: %s /dev/dsp1\n", argv[0]);
        return EXIT_FAILURE;
    }

    fd = open (argv[1], O_RDWR);
    if (fd < 0) {
        perror ("open of sound device failed");
        return EXIT_FAILURE;
    }

    /*
     * 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");
    }

    return EXIT_SUCCESS;
}