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/* mixer.c
* Simple Linux Mixer Functions
* Jim Jackson Wed Mar 15 2000
*/
/*
mixer.c: (version 1) Mar 2000
*/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include "mixer.h"
#define EFAIL -1
#define TRUE 1
#define FALSE 0
int mixFD=-1; /* Mixer File Descriptor */
int devmask=0; /* Defines which mixer channels are present */
int recmask=0; /* Defines which devices can be an input device */
int sources=0; /* Defines which devices are the current input dev(s) */
int stereodevs=0; /* Defines which devices are stereo */
char *mydevname[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_LABELS;
/* Gives a list of names for the various mixer channels */
/* mixinit(DEV) open mixer device DEV and interrogate it setting up
* various parameters.
*/
mixinit(DEV)
char *DEV;
{
if (((mixFD = open(DEV, O_RDONLY)) >= 0) &&
(ioctl(mixFD, SOUND_MIXER_READ_DEVMASK, &devmask) >= 0) &&
(ioctl(mixFD, SOUND_MIXER_READ_RECMASK, &recmask) >= 0) &&
(ioctl(mixFD, SOUND_MIXER_READ_RECSRC, &sources) >= 0) &&
(ioctl(mixFD, SOUND_MIXER_READ_STEREODEVS, &stereodevs) >= 0)) {
return(mixFD);
}
return(-1);
}
/* isdev(dev,n) check string dev against the list of mixer device names
* and if found return device/channel device number
* otherwise return -1
*/
isdev(dev)
char *dev;
{
int i,n;
if (dev==NULL) return(-1);
n=strlen(dev);
for (i=0; i<SOUND_MIXER_NRDEVICES; i++) {
if (strncasecmp(dev,MIX_DEV_NAME(i),n)==0) {
return((IS_MIX_DEV(i))?i:-1);
}
}
return(-1);
}
/* set mixer input device to dcevice number d
* this currently assumes only one input device at a time.
*/
SET_MIX_INPUT_DEV(d)
int d;
{
int i,st;
i=(d<0)?0:(1<<d);
if ((st=ioctl(mixFD, SOUND_MIXER_WRITE_RECSRC, &i))>=0) sources=i;
return(st);
}
GET_MIX_INPUT_DEV()
{
int i;
for ( i=0; i<SOUND_MIXER_NRDEVICES ; i++) {
if (sources&(1<<i)) return(i);
}
return(-1);
}
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