/*
 *  fseek file
 */

#include <stdio.h>

static char Buf[8192];

main(ac, av)
char *av[];
{
    FILE *fi;
    char buf[128];
    long i1;
    long i2;
    long r;

    if (ac == 1) {
	puts("fseek file");
	exit(1);
    }
    fi = fopen(av[1], "r+");
    if (fi == NULL) {
	puts("open failed");
	exit(1);
    }
    for (;;) {
	printf("Command -");
	fflush(stdout);
	if (gets(buf) == NULL)
	    break;

	switch(buf[0]) {
	case 'r':
	    i1 = atoi(buf + 1);
	    if (i1 >= 0 && i1 <= sizeof(Buf)) {
		r = fread(Buf, 1, i1, fi);
		printf("r = %d\n", r);
		dump(Buf, r);
	    }
	    break;
	case 'w':
	    i1 = atoi(buf + 1);
	    if (i1 >= 0 && i1 <= sizeof(Buf)) {
		setmem(Buf, i1, buf[strlen(buf)-1]);
		r = fwrite(Buf, 1, i1, fi);
		printf("r = %d\n", r);
	    }
	    break;
	case 's':
	    i1 = atoi(buf + 1);
	    strtok(buf + 1, " \t");
	    i2 = atoi(strtok(NULL, " \t"));
	    r = fseek(fi, i1, i2);
	    printf("%d = fseek(fi, %d, %d)\n", r, i1, i2);
	    break;
	case 't':
	    printf("pos = %d\n", ftell(fi));
	    break;
	case 'u':
	    printf("result = %d\n", ungetc('x', fi));
	    break;
	case 'q':
	    exit(0);
	default:
	    printf("r bytes         -read\n"
		   "w bytes c       -write\n"
		   "s off how       -seek\n"
		   "t               -tell\n"
		   "u               -ungetc\n"
		   "q               -quit\n"
		   "h               -help\n"
	    );
	    break;
	}
    }
}

dump(ptr, bytes)
unsigned char *ptr;
long bytes;
{
    printf("<");
    while (bytes > 0) {
	printf("%c", *ptr);
	--bytes;
	++ptr;
    }
    printf(">\n");
}