src/app/host-serial/extend-linux.c

// Extension routines

#include <stdio.h>
#include <poll.h>
#include <fcntl.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include "forth.h"

// #define BUFFERED_READ

#ifdef BUFFERED_READ
char buf[100];
char *bufp;
int nbuf;
#endif

cell
open_com(cell portnum)		// Open COM port
{
	struct termios kstate;
	char comname[32];
	int comfid;

	sprintf(comname, "/dev/ttyUSB%d", portnum);
	printf("%s\n",comname);
	comfid = open(comname, O_RDWR, O_EXCL);
	if (comfid < 0) {
		return (cell)comfid;
	}
	tcgetattr(comfid,&kstate);
	cfmakeraw(&kstate);
	cfsetospeed(&kstate, B115200);
	cfsetispeed(&kstate, B115200);
	kstate.c_cflag |= CLOCAL;
	kstate.c_cc[VTIME] = 1;                 /* Try for 1/10 second   */
	kstate.c_cc[VMIN] = 0;			/* Poll for character	 */

	tcsetattr(comfid, TCSANOW, &kstate);

#ifdef BUFFERED_READ
	nbuf = 0;
#endif

	return (cell)comfid;
}

cell
open_file(cell stradr)		// Open file
{
	char *name = (char *)stradr;
	int fid;
    
	printf("name %s %s\n", stradr, name);
	fid = open(name, O_RDWR, 0);
	return (cell)fid;
}

void
close_handle(cell fid)
{
	close((int)fid);
}

int
write_file(cell handle, cell len, cell buffer)
{
	size_t actual;
	actual = write((int)handle, (void *)buffer, (size_t)len);
	return actual;
}

int
read_file(cell handle, cell len, cell buffer)
{
	int actual;
	actual = read((int)handle, (void *)buffer, (size_t)len);
	return actual;
}

int
timed_read_com(cell handle, cell ms, cell len, cell buffer)
{
	int actual;

	struct pollfd pollfd;

#ifdef BUFFERED_READ
	if (nbuf) {
		actual = len > nbuf ? nbuf : len;
		memcpy((char *)buffer, bufp, actual);
		nbuf -= actual;
		bufp += actual;
		return actual;
	}
#endif

	pollfd.fd = handle;
	pollfd.events = POLLIN;
	pollfd.revents = 0;

	actual = poll(&pollfd, 1, ms);
#ifdef BUFFERED_READ
	if (actual > 0) {
		nbuf = read((int)handle, (void *)buf, 100);
		bufp = buf;
		if (nbuf < 0)
			nbuf = 0;
	}

	if (nbuf) {
		actual = len > nbuf ? nbuf : len;
		memcpy((char *)buffer, bufp, actual);
		nbuf -= actual;
		bufp += actual;
		return actual;
	}

	return actual;
#else
	if (actual > 0) {
		actual = read((int)handle, (void *)buffer, (size_t)len);
	}
#endif
        return actual;
}

cell
ms(cell nms)
{
    usleep(nms*1000);  // nanosleep(timespec) would be better
}

cell ((* const ccalls[])()) = {
	(cell (*)())open_com,			// Entry # 0
	(cell (*)())close_handle,		// Entry # 1
	(cell (*)())write_file,			// Entry # 2
	(cell (*)())read_file,			// Entry # 3
	(cell (*)())open_file,			// Entry # 4
        (cell (*)())timed_read_com,		// Entry # 5
        (cell (*)())ms,				// Entry # 6
    // Add your own routines here
};

// Forth words to call the above routines may be created by:
//
//  system also
//  0 ccall: sum      { i.a i.b -- i.sum }
//  1 ccall: byterev  { s.in -- s.out }
//
// and could be used as follows:
//
//  5 6 sum .
//  p" hello"  byterev  count type