/***** Improved Base64 encoding/decoding module ****/ / B64.C

• Base64 encoding/decoding.
• Copyright (c) 2007 Ladybridge Systems, All Rights Reserved
• This program 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.
• This program 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 this program; if not, write to the Free Software Foundation,
• Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
• START-HISTORY:
• 31 Dec 23 SD Launch - prior history suppressed
• START-DESCRIPTION:
• This module is adapted from source code published by Bob Trower.
• Copyright (c) Trantor Standard Systems Inc., 2001
• Permission is hereby granted, free of charge, to any person obtaining a
• copy of this software and associated documentation files (the "Software"),
• to deal in the Software without restriction, including without limitation
• the rights to use, copy, modify, merge, publish, distribute, sublicense,
• and/or sell copies of the Software, and to permit persons to whom the
• Software is furnished to do so, subject to the following conditions:
• The above copyright notice and this permission notice shall be included in
• all copies or substantial portions of the Software.
• THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
• IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
• FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
• AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
• LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
• FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
• DEALINGS IN THE SOFTWARE.
• END-DESCRIPTION
• START-CODE */

#include "sd.h"

/* Translation Table as described in RFC1113 */ static const unsigned char cb64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/* Translation Table to decode (created by author) */ static const unsigned char cd64[] = "|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\]^_`" "abcdefghijklmnopq";

/* ======================================================================

• encode() - Base64 encode adding padding and line breaks */

STRING_CHUNK* b64encode(STRING_CHUNK* str) { unsigned char in[3]; unsigned char out[4]; int i; int len; STRING_CHUNK* tgt; char* p; int bytes;

if (str == NULL) return NULL;

/* Allocate target string as a copy of the input length. */ ts_init(&tgt, str->string_len);

p = str->data; bytes = str->bytes;

while (str != NULL) { len = 0;

/* Read up to 3 input bytes for this block */
for (i = 0; i < 3; i++) {
  if (str != NULL) {
    in[i] = (unsigned char)(*(p++));
    len++;
    if (--bytes == 0) {
      str = str->next;
      if (str != NULL) {
        p = str->data;
        bytes = str->bytes;
      }
    }
  } else {
    in[i] = 0;
  }
}

if (len) {
  out[0] = cb64[in[0] >> 2];
  out[1] = cb64[((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4)];
  out[2] = (unsigned char)((len > 1) ? cb64[((in[1] & 0x0f) << 2) |
                                            ((in[2] & 0xc0) >> 6)]
                                     : '=');
  out[3] = (unsigned char)((len > 2) ? cb64[in[2] & 0x3f] : '=');

  ts_copy((char*)out, 4);
}

}

ts_terminate();

return tgt; }

/* ====================================================================== decode() - Decode a base64 encoded stream discarding padding, line breaks and noise */

STRING_CHUNK* b64decode(STRING_CHUNK* str) { unsigned char in[4]; unsigned char out[3]; unsigned char v; int i; int len; STRING_CHUNK* tgt; char* p; int bytes;

if (str == NULL) return NULL;

ts_init(&tgt, str->string_len);

p = str->data; bytes = str->bytes;

while (str != NULL) { /* Build up to 4 valid base64 characters, skipping noise. */ for (len = 0, i = 0; i < 4 && str != NULL; i++) { v = 0; while (str != NULL && v == 0) { if (bytes == 0) { str = str->next; if (str != NULL) { p = str->data; bytes = str->bytes; } } if (str == NULL) { break; }

    v = (unsigned char)*(p++);
    bytes--;

    v = (unsigned char)((v < 43 || v > 122) ? 0 : cd64[v - 43]);
    if (v) {
      v = (unsigned char)((v == '$') ? 0 : (v - 61));
    }
  }

  if (str != NULL) {
    len++;
    if (v) {
      in[i] = (unsigned char)(v - 1);
    } else {
      in[i] = 0;
    }
  } else {
    in[i] = 0;
  }
}

if (len) {
  out[0] = (unsigned char)(in[0] << 2 | in[1] >> 4);
  out[1] = (unsigned char)(in[1] << 4 | in[2] >> 2);
  out[2] = (unsigned char)(((in[2] << 6) & 0xc0) | in[3]);

  ts_copy((char*)out, len - 1);
}

}

ts_terminate();

return tgt; }

/* END-CODE */