base64.c

刻录光盘的程序

/* @(#)base64.c	1.2 99/12/19 Copyright 1998,1999 Heiko Eissfeldt */
#ifndef lint
static char     sccsid[] =
"@(#)base64.c	1.2 99/12/19 Copyright 1998,1999 Heiko Eissfeldt";

#endif
/*____________________________________________________________________________
//
//   CD Index - The Internet CD Index
//
//   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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
//   $Id: base64.c,v 1.1.1.3 1999/04/29 00:57:14 marc Exp $
//____________________________________________________________________________
*/
/*
 * Program:	RFC-822 routines (originally from SMTP)
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	27 July 1988
 * Last Edited:	10 September 1998
 *
 * Sponsorship:	The original version of this work was developed in the
 *		Symbolic Systems Resources Group of the Knowledge Systems
 *		Laboratory at Stanford University in 1987-88, and was funded
 *		by the Biomedical Research Technology Program of the National
 *		Institutes of Health under grant number RR-00785.
 *
 * Original version Copyright 1988 by The Leland Stanford Junior University
 * Copyright 1998 by the University of Washington
 *
 *  Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notices appear in all copies and that both the
 * above copyright notices and this permission notice appear in supporting
 * documentation, and that the name of the University of Washington or The
 * Leland Stanford Junior University not be used in advertising or publicity
 * pertaining to distribution of the software without specific, written prior
 * permission.  This software is made available "as is", and
 * THE UNIVERSITY OF WASHINGTON AND THE LELAND STANFORD JUNIOR UNIVERSITY
 * DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD TO THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE, AND IN NO EVENT SHALL THE UNIVERSITY OF
 * WASHINGTON OR THE LELAND STANFORD JUNIOR UNIVERSITY BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
 * CONTRACT, TORT (INCLUDING NEGLIGENCE) OR STRICT LIABILITY, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include "config.h"
#include <ctype.h>
#include <stdio.h>
#include <time.h>
#include <stdlib.h>

#include "base64.h"

/* NOTE: This is not true RFC822 anymore. The use of the characters
// '/', '+', and '=' is no bueno when the ID will be used as part of a URL.
// '_', '.', and '-' have been used instead
*/

/* Convert binary contents to BASE64
 * Accepts: source
 *	    length of source
 *	    pointer to return destination length
 * Returns: destination as BASE64
 */

unsigned char *rfc822_binary (src, srcl, len)
	char *src;
	unsigned long srcl;
	unsigned long *len;
{
  unsigned char *ret,*d;
  unsigned char *s = (unsigned char *) src;
  char *v = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789._";
  unsigned long i = ((srcl + 2) / 3) * 4;
  *len = i += 2 * ((i / 60) + 1);
  d = ret = (unsigned char *) malloc ((size_t) ++i);
  for (i = 0; srcl; s += 3) {	/* process tuplets */
    *d++ = v[s[0] >> 2];	/* byte 1: high 6 bits (1) */
				/* byte 2: low 2 bits (1), high 4 bits (2) */
    *d++ = v[((s[0] << 4) + (--srcl ? (s[1] >> 4) : 0)) & 0x3f];
				/* byte 3: low 4 bits (2), high 2 bits (3) */
    *d++ = srcl ? v[((s[1] << 2) + (--srcl ? (s[2] >> 6) : 0)) & 0x3f] : '-';
				/* byte 4: low 6 bits (3) */
    *d++ = srcl ? v[s[2] & 0x3f] : '-';
    if (srcl) srcl--;		/* count third character if processed */
    if ((++i) == 15) {		/* output 60 characters? */
      i = 0;			/* restart line break count, insert CRLF */
      *d++ = '\015'; *d++ = '\012';
    }
  }
  *d = '\0';			/* tie off string */

  return ret;			/* return the resulting string */
}