<?php

 // +----------------------------------------------------------------------+

 // | PHP version 5                                                        |

 // +----------------------------------------------------------------------+

 // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen                 |

 // +----------------------------------------------------------------------+

 // | This source file is subject to version 2 of the GPL license,         |

 // | that is bundled with this package in the file license.txt and is     |

 // | available through the world-wide-web at the following url:           |

 // | http://www.gnu.org/copyleft/gpl.html                                 |

 // +----------------------------------------------------------------------+

 // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org    |

 // +----------------------------------------------------------------------+

 // | Authors: James Heinrich <infoØgetid3*org>                            |

 // |          Allan Hansen <ahØartemis*dk>                                |

 // +----------------------------------------------------------------------+

 // | module.lib.data-hash.php                                             |

 // | getID3() library file.                                               |

 // | dependencies: NONE.                                                  |

 // +----------------------------------------------------------------------+

 //

 // $Id: module.lib.data_hash.php,v 1.5 2006/12/03 19:28:18 ah Exp $

 

 

 

 class getid3_lib_data_hash

 {

     

     private $getid3;

     

     

     // constructer - calculate md5/sha1 data

     public function __construct(getID3 $getid3, $algorithm) {

     

         $this->getid3 = $getid3;

         

         // Check algorithm

         if (!preg_match('/^(md5|sha1)$/', $algorithm)) {

             throw new getid3_exception('Unsupported algorithm, "'.$algorithm.'", in GetHashdata()');

         }

         

         

         //// Handle ogg vorbis files

         

         if ((@$getid3->info['fileformat'] == 'ogg') && (@$getid3->info['audio']['dataformat'] == 'vorbis')) {

 

             // We cannot get an identical md5_data value for Ogg files where the comments

             // span more than 1 Ogg page (compared to the same audio data with smaller

             // comments) using the normal getID3() method of MD5'ing the data between the

             // end of the comments and the end of the file (minus any trailing tags),

             // because the page sequence numbers of the pages that the audio data is on

             // do not match. Under normal circumstances, where comments are smaller than

             // the nominal 4-8kB page size, then this is not a problem, but if there are

             // very large comments, the only way around it is to strip off the comment

             // tags with vorbiscomment and MD5 that file.

             // This procedure must be applied to ALL Ogg files, not just the ones with

             // comments larger than 1 page, because the below method simply MD5's the

             // whole file with the comments stripped, not just the portion after the

             // comments block (which is the standard getID3() method.

 

             // The above-mentioned problem of comments spanning multiple pages and changing

             // page sequence numbers likely happens for OggSpeex and OggFLAC as well, but

             // currently vorbiscomment only works on OggVorbis files.

 

             if ((bool)ini_get('safe_mode')) {

                 throw new getid3_exception('PHP running in Safe Mode - cannot make system call to vorbiscomment[.exe]  needed for '.$algorithm.'_data.');

             }

         

             if (!preg_match('/^Vorbiscomment /', `vorbiscomment --version 2>&1`)) {

                 throw new getid3_exception('vorbiscomment[.exe] binary not found in path. UNIX: typically /usr/bin. Windows: typically c:\windows\system32.');

             }

         

             // Prevent user from aborting script

             $old_abort = ignore_user_abort(true);

 

             // Create empty file

             $empty = tempnam('*', 'getID3');

             touch($empty);

 

             // Use vorbiscomment to make temp file without comments

             $temp = tempnam('*', 'getID3');

             

             $command_line = 'vorbiscomment -w -c '.escapeshellarg($empty).' '.escapeshellarg(realpath($getid3->filename)).' '.escapeshellarg($temp).' 2>&1';

 

             // Error from vorbiscomment

             if ($vorbis_comment_error = `$command_line`) {

                 throw new getid3_exception('System call to vorbiscomment[.exe] failed.');

             } 

 

             // Get hash of newly created file

             $hash_function = $algorithm . '_file';

             $getid3->info[$algorithm.'_data'] = $hash_function($temp);

 

             // Clean up

             unlink($empty);

             unlink($temp);

 

             // Reset abort setting

             ignore_user_abort($old_abort);

             

             // Return success

             return true;

         }

 

         //// Handle other file formats

         

         // Get hash from part of file

         if (@$getid3->info['avdataoffset'] || (@$getid3->info['avdataend']  &&  @$getid3->info['avdataend'] < $getid3->info['filesize'])) {

             

             if ((bool)ini_get('safe_mode')) {

                 $getid3->warning('PHP running in Safe Mode - backtick operator not available, using slower non-system-call '.$algorithm.' algorithm.');

                 $hash_function = 'hash_file_partial_safe_mode';

             }

             else {

                 $hash_function = 'hash_file_partial';

             }

             

             $getid3->info[$algorithm.'_data'] = $this->$hash_function($getid3->filename, $getid3->info['avdataoffset'], $getid3->info['avdataend'], $algorithm);

         } 

     

         // Get hash from whole file - use built-in md5_file() and sha1_file()

         else {

             $hash_function = $algorithm . '_file';

             $getid3->info[$algorithm.'_data'] = $hash_function($getid3->filename);

         }

     }

     

     

     

     // Return md5/sha1sum for a file from starting position to absolute end position

     // Using windows system call

     private function hash_file_partial($file, $offset, $end, $algorithm) {

         

         // It seems that sha1sum.exe for Windows only works on physical files, does not accept piped data

         // Fall back to create-temp-file method:

         if ($algorithm == 'sha1'  &&  strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') {

             return $this->hash_file_partial_safe_mode($file, $offset, $end, $algorithm);

         }

         

         // Check for presence of binaries and revert to safe mode if not found

         if (!`head --version`) {

             return $this->hash_file_partial_safe_mode($file, $offset, $end, $algorithm);

         }

         

         if (!`tail --version`) {

             return $this->hash_file_partial_safe_mode($file, $offset, $end, $algorithm);

         }

         

         if (!`${algorithm}sum --version`) {

             return $this->hash_file_partial_safe_mode($file, $offset, $end, $algorithm);

         }   

         

         $size = $end - $offset;

         $command_line  = 'head -c'.$end.' '.escapeshellarg(realpath($file)).' | tail -c'.$size.' | '.$algorithm.'sum';

         return substr(`$command_line`, 0, $algorithm == 'md5' ? 32 : 40);

     }

     

     

 

     // Return md5/sha1sum for a file from starting position to absolute end position

     // Using slow safe_mode temp file

     private function hash_file_partial_safe_mode($file, $offset, $end, $algorithm) {        

 

         // Attempt to create a temporary file in the system temp directory - invalid dirname should force to system temp dir

         if (($data_filename = tempnam('*', 'getID3')) === false) {

             throw new getid3_exception('Unable to create temporary file.');

         }

 

         // Init

         $result = false;

 

         // Copy parts of file

         if ($fp = @fopen($file, 'rb')) {

 

             if ($fp_data = @fopen($data_filename, 'wb')) {

 

                 fseek($fp, $offset, SEEK_SET);

                 $bytes_left_to_write = $end - $offset;

                 while (($bytes_left_to_write > 0) && ($buffer = fread($fp, getid3::FREAD_BUFFER_SIZE))) {

                     $bytes_written = fwrite($fp_data, $buffer, $bytes_left_to_write);

                     $bytes_left_to_write -= $bytes_written;

                 }

                 fclose($fp_data);

                 $hash_function = $algorithm . '_file';

                 $result = $hash_function($data_filename);

 

             }

             fclose($fp);

         }

         unlink($data_filename);

         return $result;

     }

 

 }

 

 ?>