/*
 *  send.c
 *
 *  A hack to send a message to an RCX.
 *
 *  Under IRIX and Linux, you should be able to compile this program with
 *  cc send.c -o send.  I don'k know about other versions of Unix, although
 *  I'd be interested in hearing about compatibility issues that you are
 *  able to fix.
 *
 *  Set DEFAULTTTY to the serial device you want to use.
 *  Set the RCXTTY environment variable to override DEFAULTTTY.
 *
 *  Some additional documentation is available at:
 *
 *     http://graphics.stanford.edu/~kekoa/rcx/tools.html
 *
 *  Acknowledgements:
 *
 *     Ray Kelm sent word that send.c compiles successfully under Linux,
 *        and he passed on info about the names of the serial devices.
 *
 *  Copyright (C) 1998, Kekoa Proudfoot.  All Rights Reserved.
 *
 *  License to copy, use, and modify this software is granted provided that
 *  these notices are retained in any copies of any part of this software.
 *
 *  The author makes no guarantee that this software will compile or work
 *  properly.  Also, if you use this software, you do so at your own risk.
 * 
 *  Kekoa Proudfoot
 *  kekoa@graphics.stanford.edu
 *  9/10/98
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <stdio.h>
#include <bstring.h>
#include <sys/time.h>
#include <ctype.h>

#ifdef LINUX
#define DEFAULTTTY   "/dev/ttyS0" /* Linux - COM1 */
#else
#define DEFAULTTTY   "/dev/ttyd2" /* IRIX - second serial port */
#endif
#define RATE         B2400
#define CFLAGS       CREAD | CLOCAL | CS8 | PARENB | PARODD
#define BUFFERSIZE   4096

/* Hexdump routine - a very handy snippet from my Quake hacking days */

#define LINE_SIZE   16
#define GROUP_SIZE  4
#define UNPRINTABLE '.'

void
hexdump(void *buf, int len, char *prefix)
{
    unsigned char *b = (unsigned char *)buf;
    char           p[100] = "";
    int            i, j;

    if (prefix && prefix[0] != '\0') {
	strcat(p, prefix);
	strcat(p, " ");
    }
    
    for (i = 0; i < len / LINE_SIZE; i++) {
	printf("%s%04x: ", p, i * LINE_SIZE);
	for (j = 0; j < LINE_SIZE; j++, b++) {
	    printf("%02x %s", *b, ((j + 1) % GROUP_SIZE) ? "" : " ");
	}
	b -= LINE_SIZE;
	printf(" ");
	for (j = 0; j < LINE_SIZE; j++, b++) {
	    if (isprint(*b))
		putchar(*b);
	    else
		putchar(UNPRINTABLE);
	}
	printf("\n");
    }
    if (len % LINE_SIZE != 0) {
	printf("%s%04x: ", p, i * LINE_SIZE);
	for (j = 0; j < len % LINE_SIZE; j++, b++) {
	    printf("%02x %s", *b, ((j + 1) % GROUP_SIZE) ? "" : " ");
	}
	b -= len % LINE_SIZE;
	while (j < LINE_SIZE) {
	    printf("   %s", ((j + 1) % GROUP_SIZE) ? "" : " ");
	    j++;
	}
	printf(" ");
	for (j = 0; j < len % LINE_SIZE; j++, b++) {
	    if (isprint(*b))
		putchar(*b);
	    else
		putchar(UNPRINTABLE);
	}
	printf("\n");
    }
}

main(int argc, char **argv) {
    char *tty;
    int fd, fl;
    fd_set fds;
    struct termios ios;
    unsigned char buf[BUFFERSIZE];
    unsigned char *bp = buf;
    int i, count, sum = 0;
    struct timeval tv;

    if ((tty = getenv("RCXTTY")) == NULL)
	tty = DEFAULTTTY;

    /* Print usage if nothing on command line */

    if (argc == 1) {
	fprintf(stderr, "usage: %s byte [byte ...]\n", argv[0]); exit(1);
    }

    /* Open the tty and configure it */

    if ((fd = open(tty, O_RDWR)) == -1) {
	perror("open");	exit(1);
    }

    if (!isatty(fd)) {
	close(fd);
	fprintf(stderr, "%s: not a tty\n", tty);
	exit(1);
    }

    memset(&ios, 0, sizeof(ios));
    ios.c_cflag = CFLAGS;
    cfsetispeed(&ios, RATE);
    cfsetospeed(&ios, RATE);

    if (tcsetattr(fd, TCSANOW, &ios) == -1) {
	perror("tcsetattr"); exit(1);
    }

    /* Assemble the message */

    *bp++ = 0x55; *bp++ = 0xff; *bp++ = 0x00;
    for (i = 1; i < argc; i++) {
	unsigned char byte = strtol(argv[i], NULL, 16);
	*bp++ = byte;
	*bp++ = (~byte) & 0xff;
	sum += byte;
    }
    *bp++ = sum;
    *bp++ = ~sum;

    /* Send it */

    write(fd, buf, bp - buf);

    /* Wait for input */

    bp = buf;
    while (1) {
	FD_ZERO(&fds);
	FD_SET(fd, &fds);
	tv.tv_sec = 0;
	tv.tv_usec = 300000;
	if (select(FD_SETSIZE, &fds, NULL, NULL, &tv) == -1) {
	    perror("select"); exit(1);
	}
	if (!FD_ISSET(fd, &fds))
	    break;
	if ((count = read(fd, bp, BUFFERSIZE - (bp - buf))) == -1) {
	    perror("read"); exit(1);
	}
	bp += count;
    }

    /* Dump output and close tty file descriptor */

    hexdump(buf, bp - buf, "");

    close(fd);
}