text: /* This file is part of GDBM, the GNU data base manager.
     Copyright (C) 2011, 2013, 2016-2017 Free Software Foundation, Inc.
  
     GDBM 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 3, or (at your option)
     any later version.
  
     GDBM 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 GDBM. If not, see <http://www.gnu.org/licenses/>.   */
  
  # include "autoconf.h"
  # include "gdbmdefs.h"
  # include "gdbm.h"
  
  static char b64tab[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  static int b64val[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
  };
  
  int
  _gdbm_base64_encode (const unsigned char *input, size_t input_len,
  		     unsigned char **output, size_t *output_size,
  		     size_t *nbytes)
  {
    size_t olen = 4 * (input_len + 2) / 3 + 1;
    unsigned char *out;
  
    if (olen > *output_size)
      {
        out = realloc (*output, olen);
        if (!out)
  	return GDBM_MALLOC_ERROR;
        *output = out;
        *output_size = olen;
      }
    else
      out = *output;
    
    while (input_len >= 3)
      {
        *out++ = b64tab[input[0] >> 2];
        *out++ = b64tab[((input[0] << 4) & 0x30) | (input[1] >> 4)];
        *out++ = b64tab[((input[1] << 2) & 0x3c) | (input[2] >> 6)];
        *out++ = b64tab[input[2] & 0x3f];
        input_len -= 3;
        input += 3;
      }
  
    if (input_len > 0)
      {
        unsigned char c = (input[0] << 4) & 0x30;
        *out++ = b64tab[input[0] >> 2];
        if (input_len > 1)
  	c |= input[1] >> 4;
        *out++ = b64tab[c];
        *out++ = (input_len < 2) ? '=' : b64tab[(input[1] << 2) & 0x3c];
        *out++ = '=';
      }
    *out = 0;
    *nbytes = out - *output;
    return 0;
  }
  
  int
  _gdbm_base64_decode (const unsigned char *input, size_t input_len,
  		     unsigned char **output, size_t *output_size,
  		     size_t *inbytes, size_t *outbytes)
  {
    int rc = 0;
    int olen = input_len;
    unsigned char *out;
    size_t ins = 0;
    
    if (olen > *output_size)
      {
        out = realloc (*output, olen);
        if (!out)
  	return GDBM_MALLOC_ERROR;
        *output = out;
        *output_size = olen;
      }
    else
      out = *output;
  
    do
      {
        if (input_len < 4)
  	break;
        if (input[0] > 127 || b64val[input[0]] == -1
  	  || input[1] > 127 || b64val[input[1]] == -1
  	  || input[2] > 127 || ((input[2] != '=') && (b64val[input[2]] == -1))
  	  || input[3] > 127 || ((input[3] != '=')
  				&& (b64val[input[3]] == -1)))
  	{
  	  rc = GDBM_ILLEGAL_DATA;
  	  break;
  	}
        *out++ = (b64val[input[0]] << 2) | (b64val[input[1]] >> 4);
        if (input[2] != '=')
  	{
  	  *out++ = ((b64val[input[1]] << 4) & 0xf0) | (b64val[input[2]] >> 2);
  	  if (input[3] != '=')
  	    *out++ = ((b64val[input[2]] << 6) & 0xc0) | b64val[input[3]];
  	}
        input += 4;
        input_len -= 4;
        ins += 4;
      }
    while (input_len > 0);
    *inbytes = ins;
    *outbytes = out - *output;
    return rc;
  }
  