source: branches/version-2_5-dev/data/module/fpdf/filters/FilterASCII85.php @ 19716

<?php
//
//  FPDI - Version 1.4
//
//    Copyright 2004-2010 Setasign - Jan Slabon
//
//  Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

if (!defined('ORD_z'))
    define('ORD_z',ord('z'));
if (!defined('ORD_exclmark'))
    define('ORD_exclmark', ord('!'));
if (!defined('ORD_u'))  
    define('ORD_u', ord('u'));
if (!defined('ORD_tilde'))
    define('ORD_tilde', ord('~'));

if (!class_exists('FilterASCII85', false)) {

    class FilterASCII85 {
        
        function error($msg) {
            die($msg);
        }
        
        function decode($in) {
            $out = '';
            $state = 0;
            $chn = null;
            
            $l = strlen($in);
            
            for ($k = 0; $k < $l; ++$k) {
                $ch = ord($in[$k]) & 0xff;
                
                if ($ch == ORD_tilde) {
                    break;
                }
                if (preg_match('/^\s$/',chr($ch))) {
                    continue;
                }
                if ($ch == ORD_z && $state == 0) {
                    $out .= chr(0).chr(0).chr(0).chr(0);
                    continue;
                }
                if ($ch < ORD_exclmark || $ch > ORD_u) {
                    return $this->error('Illegal character in ASCII85Decode.');
                }
                
                $chn[$state++] = $ch - ORD_exclmark;
                
                if ($state == 5) {
                    $state = 0;
                    $r = 0;
                    for ($j = 0; $j < 5; ++$j)
                        $r = $r * 85 + $chn[$j];
                    $out .= chr($r >> 24);
                    $out .= chr($r >> 16);
                    $out .= chr($r >> 8);
                    $out .= chr($r);
                }
            }
            $r = 0;
            
            if ($state == 1)
                return $this->error('Illegal length in ASCII85Decode.');
            if ($state == 2) {
                $r = $chn[0] * 85 * 85 * 85 * 85 + ($chn[1]+1) * 85 * 85 * 85;
                $out .= chr($r >> 24);
            }
            else if ($state == 3) {
                $r = $chn[0] * 85 * 85 * 85 * 85 + $chn[1] * 85 * 85 * 85  + ($chn[2]+1) * 85 * 85;
                $out .= chr($r >> 24);
                $out .= chr($r >> 16);
            }
            else if ($state == 4) {
                $r = $chn[0] * 85 * 85 * 85 * 85 + $chn[1] * 85 * 85 * 85  + $chn[2] * 85 * 85  + ($chn[3]+1) * 85 ;
                $out .= chr($r >> 24);
                $out .= chr($r >> 16);
                $out .= chr($r >> 8);
            }
    
            return $out;
        }
        
        function encode($in) {
            return $this->error("ASCII85 encoding not implemented.");
        }
    }
}