//-------------------------------------------------------------------
//	kb2cable.cpp
//
//	This Linux program invokes services provided by our 'uart.c'
//	device-driver to transmit keyboard-input to a remote machine
//	via a serial null-modem cable, and to display any characters
//	that are received from that machine.  (In particular, it may
//	be useful for debugging a keyboard-driver on the remote PC.)
//	A user terminates this program with <ESCAPE> or <CONTROL>-C.
//
//	      compile using:  $ g++ kb2cable.cpp -o kb2cable
//	      execute using:  $ ./kb2cable
//
//	NOTE: Our 'uart.c' Linux module has to already be installed.
//
//	programmer: ALLAN CRUSE
//	written on: 26 OCT 2008 
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open()
#include <unistd.h>	// for read()
#include <stdlib.h>	// for exit() 
#include <signal.h>	// for signal()
#include <termios.h>	// for tcsetattr(), tcgetattr()


char devname[] = "/dev/uart";
struct termios	tty_orig;
int  kybd = STDIN_FILENO;


void my_action( int )
{
	tcsetattr( kybd, TCSAFLUSH, &tty_orig );
	printf( "\n" );
	exit(0);
}


int main( int argc, char **argv )
{
	// open the '/dev/uart' device-file
	int	uart = open( devname, O_RDWR );
	if ( uart < 0 ) { perror( devname ); exit(1); }

	// install signal-handler for CONTROL-C 
	tcgetattr( 0, &tty_orig );
	signal( SIGINT, my_action );

	// setup keyboard for non-canonical input
	struct termios	tty_work = tty_orig;
	tty_work.c_lflag = ~( ECHO | ICANON );
	tty_work.c_cc[ VMIN ] = 1;
	tty_work.c_cc[ VTIME ] = 0;
	tcsetattr( 0, TCSAFLUSH, &tty_work );	

	// main program-loop to process inputs from keyboard and/or uart
	int	done = 0;
	while ( !done )
		{
		fd_set	readset;
		FD_ZERO( &readset );
		FD_SET( kybd, &readset );
		FD_SET( uart, &readset );
		if ( select( 1+uart, &readset, 0, 0, 0 ) < 0 ) break;

		if ( FD_ISSET( kybd, &readset ) )
			{
			int	inch = 0;
			int	r = read( kybd, &inch, sizeof( int ) );
			if (( r == 1 )&&( inch == 0x1B )) done |= 1;
			if ( r == 1 ) write( uart, &inch, 1 );
			} 

		if ( FD_ISSET( uart, &readset ) )
			{
			int	inch = 0;
			int	r = read( uart, &inch, sizeof( inch ) );
			if (( r == 1 )&&( inch == 0x1B )) done |= 1;
			if ( r == 1 ) write( 1, &inch, 1 );
			}
		}

	tcsetattr( 0, TCSAFLUSH, &tty_orig );	
	printf( "\n" );
}