/*
    Read measurement values from METEX M-3850M
    Copyright (C) 2002  Wiesner Thomas

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
    FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
    PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
    OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
    TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
    PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
    REPAIR OR CORRECTION.
*/

#include <stdio.h>
#include <sys/termios.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

struct termios oldser;
int oldline;

int init_dmm(char *file)
{
	struct termios serterm;
	int linemode;
	int fd, buf;

	if((fd = open(file, O_RDWR | O_NOCTTY)) < 0)
		return -1;
	if(!isatty(fd))
		return -2;

	serterm.c_iflag = IGNBRK | IGNPAR;
	serterm.c_oflag = 0;
	serterm.c_cflag = CS7 | CSTOPB | CREAD | CLOCAL | B9600;
	serterm.c_lflag = 0;
	serterm.c_cc[VTIME] = 20;
	serterm.c_cc[VMIN] = 0;

	if(tcgetattr(fd, &oldser) < 0)
		return -3;
	if(tcsetattr(fd, TCSANOW, &serterm) < 0)
		return -4;
	if(ioctl(fd, TIOCMGET, &linemode) < 0)
		return -5;
	oldline = linemode;
	linemode &= ~TIOCM_RTS;
	if(ioctl(fd, TIOCMSET, &linemode) < 0)
		return -6;

	// Read out and throw away anything stil in
	// the input buffer (takes timeout)
	// Otherwise, we get strange results
	while(read(fd, &buf, 1) > 0)
		;

	return fd;
}

int read_dmm(int fd, char *data)
{
	int i;

	write(fd, "D", 1);
	for(i = 0; i < 56; i++) {
		if(read(fd, &data[i], 1) != 1) {
			printf("Timeout\n");
			return -1;
		}
	}
	return 0;
}

int close_dmm(int fd)
{
	if(tcsetattr(fd, TCSANOW, &oldser) < 0)
		return -1;
	if(ioctl(fd, TIOCMSET, &oldline) < 0)
		return -2;
	return (close(fd));
}

int main(int argc, char *argv[])
{
	int num, i, j;
	int del;
	int sfd;
	char buf[56];

	if(argc != 4) {
		printf("%s device count delay (seconds)\n"
				"if delay is 0 seconds, the refresh speed is limited by the DMM\n"
				"Please note, that the time isn't too accurate, because the dmm\n"
				"needs some time to convert and send the value.\n", argv[0]);
		return -1;
	}

	if((sfd = init_dmm(argv[1])) < 0) {
		printf("Error on opening device\n");
		return -2;
	}
	num = atoi(argv[2]);
	del = atoi(argv[3]);

	for(i = 0; i < num; i++) {
		if(read_dmm(sfd, buf) >= 0) {
			for(j = 0; j < 56; j++) {
				if(buf[j] != '\r')
					putchar(buf[j]);
				else {
					putchar('\t');
				}
			}
		}
		putchar('\n');
		fflush(stdout);
		if(del != 0)
			sleep(del);
	}
	close_dmm(sfd);
	return 0;
}