/*
    Convert a binary file into a HEX-file or back.
    Copyright (C) 2002  Wiesner Thomas

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
    FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
    PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
    OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
    TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
    PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
    REPAIR OR CORRECTION.

*/

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

#define HDPL	38		// Hex digits per line

unsigned char digits[] = {'0', '1' ,'2' ,'3' ,'4' ,'5' ,'6' ,'7' ,'8' ,'9' ,'a' ,'b' ,'c' ,'d' ,'e' ,'f'};

void b2h(unsigned char c, char *str)
{
	unsigned char buf;

	buf = c;

	c <<= 4;
	c >>= 4;
	buf >>= 4;
	str[0] = digits[buf];
	str[1] = digits[c];
	str[2] = '\0';
}

unsigned char h2b(char *str)
{
	unsigned char byte;
	int i;

	for(i = 0; i < 16 && str[0] != digits[i]; i++)
		;
	byte = i;
	byte <<= 4;
	for(i = 0; i < 16 && str[1] != digits[i]; i++)
		;
	byte = byte + i;
	return byte;
}

int main(int argc, char *argv[])
{
	FILE *ifp;
	FILE *ofp;
	int c;
	int i;
	char num[3];

	if(argc != 4) {
		printf("Usage: %s infile outfile b2h/h2b\n", argv[0]);
		return -1;
	}

	if(strcmp(argv[3], "b2h") != 0 && strcmp(argv[3], "h2b") != 0) {
		printf("Third argument must be b2h (bin2hex) or h2b (hex2bin)\n");
		return -1;
	}

	if((ifp = fopen(argv[1], "rb")) == NULL) {
		printf("Unable to open input file\n");
		return -1;
	}

	if((ofp = fopen(argv[2], "wb")) == NULL) {
		printf("Unable to open output file\n");
		return -1;
	}


	if(strcmp(argv[3], "b2h") == 0) {
		printf("Bin to Hex conversion\n");
		i = 0;
		while((c = fgetc(ifp)) != EOF) {
			b2h(c, num);
			fputc(num[0], ofp);
			fputc(num[1], ofp);
			i++;
			if(i >= HDPL) {	// Be DOS compatible; Most unix editors can hadle it.
				fputc('\r', ofp);
				fputc('\n', ofp);
				i = 0;
			}
		}
	} else {
		printf("Hex to Bin conversion\n");
		while(1) {
			do {		// Get first hex digit
				c = fgetc(ifp);
			} while(!isxdigit(c) && c != EOF);
			if(c == EOF)
				break;
			num[0] = c;

			do {		// Get second hex digit
				c = fgetc(ifp);
			} while(!isxdigit(c) && c != EOF);
			if(c == EOF)
				break;
			num[1] = c;
			num[2] = '\0';
			i = h2b(num);
			fputc(i, ofp);
		}
	}

fclose(ifp);
fclose(ofp);
return 0;
}