"Fossies" - the Fresh Open Source Software Archive

Member "tin-2.6.2/libcanlock/src/base64.c" (23 Aug 2021, 4015 Bytes) of package /linux/misc/tin-2.6.2.tar.xz:

    1 /*
    2  * Copyright (c) 1995-2001 Kungliga Tekniska Hogskolan
    3  * (Royal Institute of Technology, Stockholm, Sweden).
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  *
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  *
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * 3. Neither the name of the Institute nor the names of its contributors
   18  *    may be used to endorse or promote products derived from this software
   19  *    without specific prior written permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31  * SUCH DAMAGE.
   32  */
   33 
   34 #ifdef HAVE_CONFIG_H
   35 /* #include <config.h> */
   36 /* RCSID("$Id: base64.c,v 1.5 2001/05/28 17:33:41 joda Exp $") */
   37 #endif
   38 #include <stdlib.h>
   39 #include <string.h>
   40 #include "base64.h"
   41 
   42 
   43 static char base64_chars[] = 
   44     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   45 
   46 
   47 size_t base64_encode(const void *data, int size, char **str)
   48 {
   49    char *s, *p;
   50    int i;
   51    int c;
   52    const unsigned char *q;
   53 
   54    if (size <= 0)
   55       return 0;
   56    p = s = (char *) malloc((size_t) (size * 4 / 3 + 4));
   57    if (p == NULL)
   58       return 0;
   59    q = (const unsigned char *) data;
   60    for (i = 0; i < size;)
   61    {
   62       c = q[i++];
   63       c *= 256;
   64       if (i < size)
   65           c += q[i];
   66       i++;
   67       c *= 256;
   68       if (i < size)
   69           c += q[i];
   70       i++;
   71       p[0] = base64_chars[(c & 0x00fc0000) >> 18];
   72       p[1] = base64_chars[(c & 0x0003f000) >> 12];
   73       p[2] = base64_chars[(c & 0x00000fc0) >> 6];
   74       p[3] = base64_chars[(c & 0x0000003f) >> 0];
   75       if (i > size)
   76          p[3] = '=';
   77       if (i > size + 1)
   78          p[2] = '=';
   79       p += 4;
   80     }
   81     *p = 0;
   82     *str = s;
   83     return strlen(s);
   84 }
   85 
   86 
   87 #if 0 /* not used */
   88 static int pos(char c)
   89 {
   90    char *p;
   91    for (p = base64_chars; *p; p++)
   92    {
   93       if (*p == c)
   94          return p - base64_chars;
   95    }
   96    return -1;
   97 }
   98 
   99 
  100 #define DECODE_ERROR 0xffffffff
  101 
  102 static unsigned int token_decode(const char *token)
  103 {
  104    int i;
  105    unsigned int val = 0;
  106    int marker = 0;
  107 
  108    if (strlen(token) < 4)
  109       return DECODE_ERROR;
  110    for (i = 0; i < 4; i++) {
  111       val *= 64;
  112       if (token[i] == '=')
  113          marker++;
  114       else if (marker > 0)
  115          return DECODE_ERROR;
  116       else
  117          val += pos(token[i]);
  118    }
  119    if (marker > 2)
  120       return DECODE_ERROR;
  121    return (marker << 24) | val;
  122 }
  123 
  124 
  125 size_t base64_decode(const char *str, void *data)
  126 {
  127    const char *p;
  128    unsigned char *q;
  129 
  130    q = data;
  131    for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4)
  132    {
  133       unsigned int val = token_decode(p);
  134       unsigned int marker = (val >> 24) & 0xff;
  135       if (val == DECODE_ERROR)
  136          return 0;
  137       *q++ = (val >> 16) & 0xff;
  138       if (marker < 2)
  139          *q++ = (val >> 8) & 0xff;
  140       if (marker < 1)
  141          *q++ = val & 0xff;
  142    }
  143    /* 'q' can never be smaller than data (without 'size_t' overflow) */
  144    return (size_t) (q - (unsigned char *) data);
  145 }
  146 #endif /* 0 */