/* dodsp.c   by Michael Thorpe   2008-04-04 */

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

void dousage(int exitval) {
	if(exitval) {
		fputs(
"usage: dodsp [-38ehim] [-s <#>] [-d <dev>] <program> [<arg1> [<arg2> [..]]]\n",stderr);
	} else {
		fputs(
"usage: dodsp [-38ehim] [-s <#>] [-d <dev>] <program> [<arg1> [<arg2> [..]]]\n"
"\t-3      pass device as fd 3 instead of 0 or 1\n"
"\t-8      8-bit samples (default is 16)\n"
"\t-d <f>  device file to use (default is /dev/dsp)\n"
"\t-e      non-native-endian 16-bit samples\n"
"\t-i      change stdin instead of stdout\n"
"\t-h      show this help message\n"
"\t-m      mono mode (default is stereo)\n"
"\t-s <#>  samples per second (default is 44100)\n",stdout);
	}
	exit(exitval);
}

int main(int argc,char **argv) {
	int c,f;
	int format=AFMT_S16_NE,reqfd=1,stereo=1,speed=44100;
	char *dev="/dev/dsp";

	while(EOF != (c=getopt(argc,argv,"+38ehims:d:"))) {
		switch(c) {
		case '3':
			reqfd=3;
			break;
		case '8':
			if(format != AFMT_S16_NE)
				dousage(1);
			format=AFMT_S8;
			break;
		case 'd':
			dev=optarg;
			break;
		case 'e':
			if(format != AFMT_S16_NE)
				dousage(1);
			format=AFMT_S16_LE+AFMT_S16_BE-AFMT_S16_NE;
			break;
		case 'h':
			dousage(0);
			break;
		case 'i':
			reqfd=0;
			break;
		case 's':
			speed=atoi(optarg);
			break;
		case 'm':
			stereo=0;
			break;
		case '?':
			dousage(1);
			break;
		}
	}
	if(optind==argc)
		dousage(1);
	close(reqfd);
	f=open(dev,reqfd?3==reqfd?O_RDWR:O_WRONLY:O_RDONLY);
	if(f==-1) {
		perror("open");
		return(1);
	}
	if(f != reqfd) {
		dup2(f,reqfd);
		close(f);
	}
	if(ioctl(f,SNDCTL_DSP_SETFMT,&format)) {
		perror("ioctl");
		return(-1);
	}
	c=speed;
	if(ioctl(f,SNDCTL_DSP_SPEED,&c)) {
		perror("ioctl");
		return(-1);
	}
	if(c != speed) {
		fprintf(stderr,"Asked for speed of %d, got speed of %d\n",speed,c);
		return(-1);
	}
	if(ioctl(f,SNDCTL_DSP_STEREO,&stereo)) {
		perror("ioctl");
		return(-1);
	}
	execvp(argv[optind],argv+optind);
	perror("exec");
	return(-1);
}