base64.c

/*****************************************************************************
 *                                  _   _ ____  _     
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 *  The contents of this file are subject to the Mozilla Public License
 *  Version 1.0 (the "License"); you may not use this file except in
 *  compliance with the License. You may obtain a copy of the License at
 *  http://www.mozilla.org/MPL/
 *
 *  Software distributed under the License is distributed on an "AS IS"
 *  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 *  License for the specific language governing rights and limitations
 *  under the License.
 *
 *  The Original Code is Curl.
 *
 *  The Initial Developer of the Original Code is Daniel Stenberg.
 *
 *  Portions created by the Initial Developer are Copyright (C) 1998.
 *  All Rights Reserved.
 *
 * ------------------------------------------------------------
 * Main author:
 * - Daniel Stenberg <daniel@haxx.se>
 *
 * 	http://curl.haxx.se
 *
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 * $Date$
 * $Author$
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 * ------------------------------------------------------------
 ****************************************************************************/

#include <stdio.h>

/* ---- Base64 Encoding --- */
static char table64[]=
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
/*
 * base64Encode()
 *
 * Returns the length of the newly created base64 string. The third argument
 * is a pointer to an allocated area holding the base64 data. If something
 * went wrong, -1 is returned.
 *
 * Modifed my version to resemble the krb4 one. The krb4 sources then won't
 * need its own.
 *
 */
int base64Encode(char *indata, int insize, char **outptr)
{
  unsigned char ibuf[3];
  unsigned char obuf[4];
  int i;
  int inputparts;
  char *output;
  char *base64data;

  if(0 == insize)
    insize = strlen(indata);

  base64data = output = (char*)malloc(insize*4/3+4);
  if(NULL == output)
    return -1;

  while(insize > 0) {
    for (i = inputparts = 0; i < 3; i++) { 
      if(*indata) {
        inputparts++;
        ibuf[i] = *indata;
        indata++;
        insize--;
      }
      else
        ibuf[i] = 0;
    }
                       
    obuf [0] = (ibuf [0] & 0xFC) >> 2;
    obuf [1] = ((ibuf [0] & 0x03) << 4) | ((ibuf [1] & 0xF0) >> 4);
    obuf [2] = ((ibuf [1] & 0x0F) << 2) | ((ibuf [2] & 0xC0) >> 6);
    obuf [3] = ibuf [2] & 0x3F;

    switch(inputparts) {
    case 1: /* only one byte read */
      sprintf(output, "%c%c==", 
              table64[obuf[0]],
              table64[obuf[1]]);
      break;
    case 2: /* two bytes read */
      sprintf(output, "%c%c%c=", 
              table64[obuf[0]],
              table64[obuf[1]],
              table64[obuf[2]]);
      break;
    default:
      sprintf(output, "%c%c%c%c", 
              table64[obuf[0]],
              table64[obuf[1]],
              table64[obuf[2]],
              table64[obuf[3]] );
      break;
    }
    output += 4;
  }
  *output=0;
  *outptr = base64data; /* make it return the actual data memory */

  return strlen(base64data); /* return the length of the new data */
}
/* ---- End of Base64 Encoding ---- */