/* full_duplex.c */
/*
 * Copyright (c) 2001 Bruce R. Montague <brucem@mail.cruzio.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHERIN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THEPOSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 *   >full_duplex record_filename play_filename {bytes}
 */


#include  <stdlib.h>
#include  <sys/types.h>
#include  <unistd.h>
#include  <stdio.h>
#include  <errno.h>
#include  <fcntl.h>

#define REC_BYTES  300000 
#define BUF_LEN  512

void do_save_work( char *rec_filename, int record_bytes );
void do_play_work( char *play_filename );


/* Args are 0:programname  1:rec_filename 2:play_filename 3:{bytes} */
/*-------------------------------------------------------------*/
int
main( int argc, char *argv[] ) 
{
	char *rec_filename;
	char *play_filename;
	int   pid,child_status,record_bytes;

	if( argc < 3) {
	    printf( "\n\n  >full_duplex record.pcm play.pcm {record_bytes}\n\n" );
	    exit(1);
	}

	rec_filename  = argv[1];
	play_filename = argv[2];

	record_bytes = REC_BYTES;
	if( argc >= 4 ) {
	    record_bytes = atoi( argv[3] );
	}

	open_au_dev( "/dev/dsp", O_RDWR, 0 );

	pid = fork();
	if( pid < 0 ) {
	    printf( "\n Cant fork, err=%d.\n", pid );
	    exit(1);
	}

	if( !pid ) {				/* Child. */
   	    do_save_work( rec_filename, record_bytes );
	    close_au_dev();
	    exit(0); 
	} else {
	    do_play_work( play_filename );	/* Parent. */
	    wait( &child_status );
	}

	close_au_dev();
}


/*-------------------------------------------------------------*/
void
do_save_work( char *rec_filename, int record_bytes ) {
	unsigned char  *au_buf_p;
	int             fout;
	int             bytes, au_bytes_in, len;

	fout = open( rec_filename, (O_WRONLY|O_CREAT|O_TRUNC), 0740 );
	if( 0 > fout ) {
	    printf( "\n Cant open file <%s>!\n", rec_filename );
	    perror( "" );
	    exit(1);
	}

	bytes = 0;

	for(;;) {
	    au_bytes_in = read_au_dev( &au_buf_p );
	    /* printf( "\n au_bytes=%d.\n", au_bytes_in ); */

	    len = write( fout, au_buf_p, au_bytes_in );
	    if( 0 >= len ) {
		printf( "\n File write err? len=%d.\n", len );
		exit(1);
	    }

	    bytes += len;

	    if( bytes >= record_bytes ) break;
	} 

	close( fout );
}


/*-------------------------------------------------------------*/
void
do_play_work( char *play_filename ) {
	char *buf_play_p;
	int   fin, bytes_in;

	buf_play_p = malloc( BUF_LEN );
	if( !buf_play_p ) {
	    printf( "\n Cant malloc play buf!\n" );
	}

	fin = open( play_filename, O_RDONLY, 0 );
	if( !fin ) {
	    printf( "\n Cant open file <%s>\n", play_filename );
	    exit(1);
	}

	for(;;) {
	    bytes_in = read( fin, buf_play_p, 512 );
	    if( !bytes_in ) break;

	    write_au_dev( buf_play_p, bytes_in );
   	}

	close( fin );
}