/*  File   : tag.c
    Author : Richard A. O'Keefe
    Updated: 9/10/99
    Purpose: Tag a model file for a programming contest.

    USAGE
	pcfptag [-%] RawModel >Model

	The option (shown as %) is the magic character to use,
	if it is not $.

	RawModel is the name of a readable text file.
	It is copied to Model,
	- adding $<char no>= at the front if the magic character is not $
	- replacing <magic> by <magic>$
	- replacing <newline> by <magic>s<newline>
	- replacing <end of file> by <magic>#<magic>!<newline><end of file>
*/

#include <stdio.h>
#include <stdlib.h>

char const prog[] = "pcfptag";

int magic = '$';

void tag(char const *name) {
    FILE *o = stdout;
    FILE *f;
    int m = magic;
    int c;

    if (name[0] == '-' && name[1] == '\0') {
	f = stdin;
    } else {
        f = fopen(name, "r");
        if (f == 0) {
            fprintf(stderr, "%s: can't read '%s'\n", prog, name);
            exit(EXIT_FAILURE);
	}
    }
    while ((c = getc(f)) >= 0) {
	if (c == m) {
	    putc(m, o);
	    putc('$', o);
	} else
	if (c == '\n') {
	    putc(m, o);	
	    putc(' ', o);
	    putc(c, o);
	} else {
	    putc(c, o);
	}
    }
    if (!feof(f)) {
	fprintf(stderr, "%s: I/O error reading '%s'\n", prog, name);
	exit(EXIT_FAILURE);
    }
    putc(m, o); putc('#', o);
    putc(m, o); putc('!', o); putc('\n', o);
    if (f != stdin) fclose(f);
}

int main(int argc, char **argv) {
    switch (argc) {
	case 3:
	    printf("%c", magic);
	    magic = argv[1][0] == '-' && argv[1][1] != '\0'
	            ? argv[1][1] : argv[1][0];
	    printf("%d=%c! set magic to %c\n", magic, magic, magic);
	    tag(argv[2]);
	    break;
	case 2:
	    tag(argv[1]);
	    break;
	case 1:
	    tag("-");
	    break;
	default:	    
	    fprintf(stderr, "Usage: %s [-%%] Raw >Model\n", prog);
	    exit(EXIT_FAILURE);
    }	    
    return EXIT_SUCCESS;
}