/* sound volume get/set code based on code from here:
   https://stackoverflow.com/a/7661176/5737011
   https://stackoverflow.com/questions/7657624/get-master-sound-volume-in-c-in-linux/7661176#7661176 */

#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/soundcard.h>
#include <sys/ioctl.h>

#define OSS_DEV "/dev/dsp"

extern int oss_volume_get(unsigned char * r) {
  int fd, err;
  long v;
  if((fd=open(OSS_DEV, O_WRONLY))<0) return -1;
  if(ioctl(fd, SOUND_MIXER_READ_VOLUME, &v)<0) { err=errno; close(fd); errno=err; return -1; }
  close(fd);
  r[0] = v&255;
  r[1] = (v>>8)&255;
  return 0;
}


extern int oss_volume_set(unsigned char a, unsigned char b) {
  int fd, err;
  long v;
  if(a>100) a=100; if(b>100) b=100;
  v = a | (((unsigned)b) << 8);
  if((fd=open(OSS_DEV, O_WRONLY))<0) return -1;
  if(ioctl(fd, SOUND_MIXER_WRITE_VOLUME, &v)<0) { err=errno; close(fd); errno=err; return -1; }
  close(fd);
  return 0;
}