text: /*
   * libEtPan! -- a mail stuff library
   *
   * Copyright (C) 2001, 2005 - Juergen Graf
   * 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 libEtPan! project 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 AUTHORS 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 AUTHORS 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.
   */
  
  /*
   * $Id: base64.c,v 1.3 2005/06/01 12:21:57 smarinier Exp $
   */
  
  #include <stdlib.h>
  #include <lem/unicode.h>
  
  #define OUTPUT_SIZE 513
  #define CHAR64(c)  (((c) < 0 || (c) > 127) ? -1 : index_64[(c)])
  
  static char index_64[128] = {
      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
      52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
      -1, 0, 1, 2,  3, 4, 5, 6,  7, 8, 9,10, 11,12,13,14,
      15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
      -1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
      41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
  };
  
  static char basis_64[] =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  char* lem::encode_base64( const char * in, int len )
  {
    char * output, * tmp;
    unsigned char oval;
    int out_len;
  
    out_len = ((len + 2) / 3 * 4) + 1;
  
    if ((len > 0) && (in == NULL))
      return NULL;
  
    output = new char[out_len];
    if (!output)
      return NULL;
      
    tmp = output;
    while (len >= 3) {
      *tmp++ = basis_64[in[0] >> 2];
      *tmp++ = basis_64[((in[0] << 4) & 0x30) | (in[1] >> 4)];
      *tmp++ = basis_64[((in[1] << 2) & 0x3c) | (in[2] >> 6)];
      *tmp++ = basis_64[in[2] & 0x3f];
      in += 3;
      len -= 3;
    }
    if (len > 0) {
      *tmp++ = basis_64[in[0] >> 2];
      oval = (in[0] << 4) & 0x30;
      if (len > 1) oval |= in[1] >> 4;
      *tmp++ = basis_64[oval];
      *tmp++ = (len < 2) ? '=' : basis_64[(in[1] << 2) & 0x3c];
      *tmp++ = '=';
    }
  
   *tmp = '\0';
      
   return output;
  }
  
  
  char* lem::decode_base64( const char * in, int len )
  {
    char * output, * out;
    int i, c1, c2, c3, c4, out_len;
  
    out_len = 0;
    
    size_t outsize = len*2;
    output = new char[outsize];
    if (output == NULL)
      return NULL;
  
    out = output;
  
    if( in[0] == '+' && in[1] == ' ' )
      in += 2;
    
    for (i = 0; i < (len / 4); i++) {
      c1 = in[0];
      c2 = in[1];
      c3 = in[2];
      c4 = in[3];
      if (CHAR64(c1) == -1 || CHAR64(c2) == -1 || 
          (c3 != '=' && CHAR64(c3) == -1) || 
          (c4 != '=' && CHAR64(c4) == -1))
        return NULL;
  
      in += 4;
      *output++ = (CHAR64(c1) << 2) | (CHAR64(c2) >> 4);
      if( ++out_len >= outsize )
        return NULL;
  
      if (c3 != '=') {
        *output++ = ((CHAR64(c2) << 4) & 0xf0) | (CHAR64(c3) >> 2);
        if (++out_len >= outsize)
          return NULL;
        
        if (c4 != '=') {
          *output++ = ((CHAR64(c3) << 6) & 0xc0) | CHAR64(c4);  
          if (++out_len >= outsize)
            return NULL;
        }
      }
    }
    
    *output = 0;
    
    return out;
  }
  