/*
 * volume.C
 *
 *   Renaud Waldura <waldura@essi.fr>
 *
 *            Tue Sep 13 19:39:32 1994
 *            Mon Nov 21 15:32:23 1994
 *    
 *   To adjust the speaker volume on a SparcStation IPC.
 *
 */

#include <fcntl.h>
#include <unistd.h>
#include <iostream.h>
#include <stdlib.h>

#include <sys/stropts.h>
#include <sun/audioio.h>


#include <errno.h>
#define dieif(e) if (e) { perror(argv[0]); return errno; } else {} 

#define DEFAULT_INCREMENT (AUDIO_MAX_GAIN / 20)
#define scale(n) (AUDIO_MAX_GAIN * (n) / 100)


void usage (const char* progname)
{
    cerr << "Usage: " << progname 
	 << " [=value|++|+value|--|-value] ; value in 0..100" << endl;
    exit(1);
}


main (int argc, char* argv[ ])
{
    int print_vol = 0;

    if (argc == 1)
       print_vol = 1;
    else if (!(argc == 2 && 
	      (argv[1][0] == '-' || argv[1][0] == '+' || argv[1][0] == '=')))
	usage(argv[0]);

    int au = open("/dev/audioctl", O_RDWR); // open audio driver
    dieif( au < 0 );

    audio_info_t aif;
    dieif( ioctl(au, AUDIO_GETINFO, &aif) < 0 ); // get speaker volume
    int vol = aif.play.gain;

    if (print_vol)		//  no argument, just print the current volume
    {
       cout << 100 * vol / AUDIO_MAX_GAIN << endl;
       return 0;
    }

    if (argv[1][0] == '=')	// argument is =
	vol = scale(atoi(&argv[1][1]));
    else if (argv[1][0] == '+')
	if (argv[1][1] == '+')	// argument is ++
	    vol += DEFAULT_INCREMENT;
	else			// argument is +n
	    vol += scale(atoi(&argv[1][1]));
    else if (argv[1][0] == '-')
	if (argv[1][1] == '-')	// argument is --
	    vol -= DEFAULT_INCREMENT;
	else			// argument is -n
	    vol -= scale(atoi(&argv[1][1]));

    if (vol > AUDIO_MAX_GAIN)
	vol = AUDIO_MAX_GAIN;
    else if (vol < AUDIO_MIN_GAIN)
	vol = AUDIO_MIN_GAIN;

    AUDIO_INITINFO(&aif);
    aif.play.gain = vol;

    dieif( ioctl(au, AUDIO_SETINFO, &aif) < 0 ); // change volume value

    return close(au);		// and close keyboard driver
}