/*

  * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan

  * (Royal Institute of Technology, Stockholm, Sweden).
  * 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.
  *
  * 3. Neither the name of the Institute nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
  */
 

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #elif defined(_MSC_VER)
 #include "config-msvc.h"
 #endif
 

 #include "syshead.h"
 
 #include "base64.h"
 
 #include "memdbg.h"
 

 static char base64_chars[] =

     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

 /*
  * base64 encode input data of length size to malloced
  * buffer which is returned as *str.  Returns string
  * length of *str.
  */

 int

 openvpn_base64_encode(const void *data, int size, char **str)

 {
     char *s, *p;
     int i;
     int c;
     const unsigned char *q;
 

     if (size < 0)

     {
         return -1;
     }

     p = s = (char *) malloc(size * 4 / 3 + 4);
     if (p == NULL)

     {
         return -1;
     }

     q = (const unsigned char *) data;
     i = 0;

     for (i = 0; i < size; )
     {

         c = q[i++];
         c *= 256;
         if (i < size)
         {
             c += q[i];
         }
         i++;
         c *= 256;
         if (i < size)
         {
             c += q[i];
         }
         i++;
         p[0] = base64_chars[(c & 0x00fc0000) >> 18];
         p[1] = base64_chars[(c & 0x0003f000) >> 12];
         p[2] = base64_chars[(c & 0x00000fc0) >> 6];
         p[3] = base64_chars[(c & 0x0000003f) >> 0];
         if (i > size)
         {
             p[3] = '=';
         }
         if (i > size + 1)
         {
             p[2] = '=';
         }
         p += 4;

     }
     *p = 0;
     *str = s;
     return strlen(s);
 }
 

 static int

 pos(char c)
 {
     char *p;
     for (p = base64_chars; *p; p++)

     {

         if (*p == c)
         {
             return p - base64_chars;
         }

     }

     return -1;
 }
 

 #define DECODE_ERROR 0xffffffff
 
 static unsigned int
 token_decode(const char *token)
 {
     int i;
     unsigned int val = 0;
     int marker = 0;

     if (!token[0] || !token[1] || !token[2] || !token[3])

     {
         return DECODE_ERROR;
     }

     for (i = 0; i < 4; i++)
     {

         val *= 64;
         if (token[i] == '=')
         {
             marker++;
         }
         else if (marker > 0)
         {
             return DECODE_ERROR;
         }
         else
         {
             val += pos(token[i]);
         }

     }
     if (marker > 2)

     {
         return DECODE_ERROR;
     }

     return (marker << 24) | val;
 }

 /*
  * Decode base64 str, outputting data to buffer
  * at data of length size.  Return length of
  * decoded data written or -1 on error or overflow.
  */

 int

 openvpn_base64_decode(const char *str, void *data, int size)

 {
     const char *p;
     unsigned char *q;

     unsigned char *e = NULL;

 
     q = data;

     if (size >= 0)

     {
         e = q + size;
     }

     for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4)
     {

         unsigned int val = token_decode(p);
         unsigned int marker = (val >> 24) & 0xff;
         if (val == DECODE_ERROR)
         {
             return -1;
         }
         if (e && q >= e)
         {
             return -1;
         }
         *q++ = (val >> 16) & 0xff;
         if (marker < 2)
         {
             if (e && q >= e)
             {
                 return -1;
             }
             *q++ = (val >> 8) & 0xff;
         }
         if (marker < 1)
         {
             if (e && q >= e)
             {
                 return -1;
             }
             *q++ = val & 0xff;
         }

     }
     return q - (unsigned char *) data;
 }