search/Zend/Search/Lucene/Index/Term.php

   1 <?php
   2 /**
   3  * Zend Framework
   4  *
   5  * LICENSE
   6  *
   7  * This source file is subject to the new BSD license that is bundled
   8  * with this package in the file LICENSE.txt.
   9  * It is also available through the world-wide-web at this URL:
  10  * http://framework.zend.com/license/new-bsd
  11  * If you did not receive a copy of the license and are unable to
  12  * obtain it through the world-wide-web, please send an email
  13  * to license@zend.com so we can send you a copy immediately.
  14  *
  15  * @category   Zend
  16  * @package    Zend_Search_Lucene
  17  * @subpackage Index
  18  * @copyright  Copyright (c) 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
  19  * @license    http://framework.zend.com/license/new-bsd     New BSD License
  20  */
  21
  22
  23 /**
  24  * A Term represents a word from text.  This is the unit of search.  It is
  25  * composed of two elements, the text of the word, as a string, and the name of
  26  * the field that the text occured in, an interned string.
  27  *
  28  * Note that terms may represent more than words from text fields, but also
  29  * things like dates, email addresses, urls, etc.
  30  *
  31  * @category   Zend
  32  * @package    Zend_Search_Lucene
  33  * @subpackage Index
  34  * @copyright  Copyright (c) 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
  35  * @license    http://framework.zend.com/license/new-bsd     New BSD License
  36  */
  37 class Zend_Search_Lucene_Index_Term
  38 {
  39     /**
  40      * Field name or field number (depending from context)
  41      *
  42      * @var mixed
  43      */
  44     public $field;
  45
  46     /**
  47      * Term value
  48      *
  49      * @var string
  50      */
  51     public $text;
  52
  53
  54     /**
  55      * Object constructor
  56      */
  57     public function __construct($text, $field = null)
  58     {
  59         $this->field = ($field === null)?  Zend_Search_Lucene::getDefaultSearchField() : $field;
  60         $this->text  = $text;
  61     }
  62
  63
  64     /**
  65      * Returns term key
  66      *
  67      * @return string
  68      */
  69     public function key()
  70     {
  71         return $this->field . chr(0) . $this->text;
  72     }
  73
  74     /**
  75      * Get term prefix
  76      *
  77      * @param integer $length
  78      * @return string
  79      */
  80     public static function getPrefix($str, $length)
  81     {
  82         $prefixBytes = 0;
  83         $prefixChars = 0;
  84         while ($prefixBytes < strlen($str)  &&  $prefixChars < $length) {
  85             $charBytes = 1;
  86             if ((ord($str[$prefixBytes]) & 0xC0) == 0xC0) {
  87                 $charBytes++;
  88                 if (ord($str[$prefixBytes]) & 0x20 ) {
  89                     $charBytes++;
  90                     if (ord($str[$prefixBytes]) & 0x10 ) {
  91                         $charBytes++;
  92                     }
  93                 }
  94             }
  95
  96             if ($prefixBytes + $charBytes > strlen($str)) {
  97                 // wrong character
  98                 break;
  99             }
 100
 101             $prefixChars++;
 102             $prefixBytes += $charBytes;
 103         }
 104
 105         return substr($str, 0, $prefixBytes);
 106     }
 107 }
 108