/*
 * numchar.c v1.0 (1999-08-03)
 *
 * This program finds all possible ways a phone number may be expressed
 * using the US system in which digits of a phone number can be replaced
 * by characters.
 *
 *===============================================================================*
 *
 * Copyright (c) 1999 G. Adam Stanislav
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

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

#ifdef _WIN32
#define	PHDECODE	"PHDECODE.EXE"
#else
#define	PHDECODE	"phdecode"
#endif

static int onepass = 0;
static unsigned char *source = NULL;
static unsigned char *destin = NULL;
static const unsigned char digits[24] = "ABCDEFGHIJKLMNOPRSTUVWXY";

static void displaynumber(int digit) {
	register unsigned char c, save;
	register int i, j;

	c = save = destin[digit];

	if (c == '\0') {
		printf("\t%s\n", destin);
	}
	else {
		switch (toupper(c)) {
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		case '*':
		case '#':
		case '-':
			break;
		case 'A':
		case 'B':
		case 'C':
			c = '2';
			break;
		case 'D':
		case 'E':
		case 'F':
			c = '3';
			break;
		case 'G':
		case 'H':
		case 'I':
			c = '4';
			break;
		case 'J':
		case 'K':
		case 'L':
			c = '5';
			break;
		case 'M':
		case 'N':
		case 'O':
			c = '6';
			break;
		case 'P':
		case 'R':
		case 'S':
			c = '7';
			break;
		case 'T':
		case 'U':
		case 'V':
			c = '8';
			break;
		case 'W':
		case 'X':
		case 'Y':
			c = '9';
			break;
		case 'Q':
		case 'Z':
			c = '?';
			break;
		default:
			c = '-';
			break;
		}

		destin[digit] = c;
		displaynumber(digit+1);

		if (onepass == 0 && c >= '2' && c <= '9') {
			i = c - '2';

			for (j = 0; j < 3; j++) {
				destin[digit] = digits[i*3+j];
				displaynumber(digit+1);
			}
		}

		destin[digit] = save;
	}
}

static int numchar(char *src) {
	if (src == NULL) return 1;

	destin = strdup(src);
	if (destin == NULL) {
		fprintf(stderr, "NUMCHAR: Not enough memory.\n");
		return 1;
	}

	source = src;
	displaynumber(0);
	free(destin);
	source = NULL;
	destin = NULL;

	return 0;
}

int main(int argc, char *argv[]) {
	int i;

	if (strstr(argv[0], PHDECODE))
		onepass = 1;

	for (i = 1; i < argc; i++) {
		printf("\n%s:\n" + (i == 1), argv[i]);
		if (numchar(argv[i])) return 1;
	}

	return 0;
}