base64.cc

/*
 *	DMG2ISO
 *	base64.cc
 *
 *	Copyright (c) 2004 vu1tur <v@vu1tur.eu.org>
 *	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.
 *
 *	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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "base64.h"
#include <stdlib.h>

bool is_base64(const char c) {
	if ( (c >= 'A' && c <= 'Z') || 
		(c >= 'a' && c <= 'z') || 
          (c >= '0' && c <= '9') ||
	      c == '+' || 
	      c == '/' || 
	      c == '=') return true;
	return false;
}

void cleanup_base64(char *inp, const unsigned int size) {
	char *tinp1,*tinp2;
	tinp1 = inp;
     tinp2 = inp;
     for (unsigned int i = 0; i < size; i++) {
     	if (is_base64(*tinp2)) {
          	*tinp1++ = *tinp2++;
          }
          else {
          	*tinp1 = *tinp2++;
          }
     }
     *(tinp1) = 0;
}

unsigned char decode_base64_char(const char c) {
	if (c >= 'A' && c <= 'Z') return c - 'A';
	if (c >= 'a' && c <= 'z') return c - 'a' + 26;
	if (c >= '0' && c <= '9') return c - '0' + 52;
	if (c == '+') return 62;
     if (c == '=') return 0;
	return 63;   
}
bool decode_base64(const char *inp, unsigned int isize, 
			char *out, unsigned int *osize) {
     char *tinp = (char*)inp; 
     char *tout;
     *osize = isize / 4 * 3;
     if (inp != out) {
	     tout = (char*) malloc(*osize);
          out = tout;
	}
     else {
          tout = tinp;
     }
     for(unsigned int i = 0; i < isize >> 2; i++) {
		*tout++ = (decode_base64_char(*tinp++) << 2) | (decode_base64_char(*tinp) >> 4);
          *tout++ = (decode_base64_char(*tinp++) << 4) | (decode_base64_char(*tinp) >> 2);
          *tout++ = (decode_base64_char(*tinp++) << 6) | decode_base64_char(*tinp++);
	}
     if (*(tinp-1) == '=') (*osize)--;
     if (*(tinp-2) == '=') (*osize)--;
}