#define NP1		"np1"
#define NP2		"np2"
#define MAX_BUF_SIZE	255

#include <stdio.h>
#include <string.h>
#include <stdlib.h>	
#include <errno.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

/*-----------------------------------
the idea here is
1. kb.c creates:
    ()  file kbData.txt to send keyboard chars to LC3:kbDevice
    ()  file kbHS1.txt to send STX to LC3:kbdevice.
    ()  NAMED pipe kbHS2.txt to get ACK from LC3:kbdevice.
    ()  NAMED pipe dispData.txt to get char from LC3:dispDevice.
    ()  write( kbHS.txt, ACK )
    ()  write( dispHS.txt, ACK )
    ()  fork()                                () child: exec( a.out )
    LOOP:                                     LOOP-kbDevice:
                                              () readmem( kbHS.txt )
    () if (read(kbHS.txt) == ACK )
         if (read(stdio) == nonNull )
           write( kbData.txt, char )
           write( kbHS.txt, STX )
                                              () if readmem( kbHS.txt ) == STX
                                                     readmem( kbData.txt, char )
                                                     newData <== char
                                                     fwrite( kbHS.txt, ACK )
                                              () go LOOP-kbDevice
                                              LOOP-dispDevice:
                                              () DDR <== char
                                              () if readmem( dispHS.txt ) == ACK
                                                     fwrite( dispData.txt, char)
                                                     fwrite( dispData.txt, STX)
                                                 else goto if (ACK)
                                              goto LOOP-dispDevice
    () if (read(dispHS.txt) == STX)
           char = read(dispData.txt)
           write( dispHS.txt, ACK)
           write(stdout, char)
   goto LOOP-kb.c

.....................................................................
...keyboard..........................................................
...|.................................................................
..(c)................................................................
...|..........|=======[A]==kb-3.c-[_]<===fr'A===kbHS2<=====(A)===|...
...|..........|...............|..................................^...
..fr'c........|...............|..................................|..
...|..........|...............|..................................|...
...|==>[__]-kb-1.c===[c]===kb-2.c==fw'c==>kbData==rmem'c=>|......|...
.........^..|.|..............\............................|...$fw'ACK
.........|..|.|===[d]====>|...fw'STX.....................(c)......\..
.........|..|.............|...|...........................|........\.
......fr'd..|.............|...|==>kbHS1==rmem'T==LC3kb-1===LC3kb-2==|
.........|..|.............|.......................\......./..|.......
.........|..|<==========kb-4.c==(d)==>stdout.......\=====/..w'c......
........(d)..................................................|......
.........|<=====vidData<===(d)<==$fw<===(d)<==LC3vid........(c)......
.........................................................../==>kBDR..
*/

int main(int argc, char *argv[])
{
    int rdfd, wrfd, ret_val, count, numread;
    char buf[MAX_BUF_SIZE];

    /* Create the first named - pipe */
    ret_val = mkfifo(NP1, 0666);

    if ((ret_val == -1) && (errno != EEXIST)) {
        perror("Error creating the named pipe");
        exit (1);
    }

    ret_val = mkfifo(NP2, 0666);

    if ((ret_val == -1) && (errno != EEXIST)) {
        perror("Error creating the named pipe");
        exit (1);
    }

    /* Open the first named pipe for reading */
    rdfd = open(NP1, O_RDONLY);

    /* Open the second named pipe for writing */
    wrfd = open(NP2, O_WRONLY);

    /* Read from the first pipe */
    numread = read(rdfd, buf, MAX_BUF_SIZE);

    buf[numread] = '0';

    printf("Full Duplex Server : Read From the  pipe : %sn", buf);

    /* Convert to the string to upper case */
    count = 0;
    while (count < numread) {
        buf[count] = toupper(buf[count]);
        count++;
    }

    /* 
     * Write the converted string back to the second 
     * pipe 
     */    
    write(wrfd, buf, strlen(buf));
}