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406 lines
16 KiB
406 lines
16 KiB
<?php
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//
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// NOTICE OF COPYRIGHT
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//
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// Original code:
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//
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// Drupal - The copyright of both the Drupal software and the
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// "Druplicon" logo belongs to all the original authors,
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// though both are licensed under the GPL.
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// http://drupal.org
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//
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// Modifications:
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//
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// Moodle - Modular Object-Oriented Dynamic Learning Environment
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// http://moodle.com
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//
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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//
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/**
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* Based on Drupal's search.module version 1.224
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*
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* {@link http://cvs.drupal.org/viewcvs/drupal/drupal/modules/search/search.module?view=markup}
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*
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* Usage: $tokens = tokenise_text($text)
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* Returns an array of tokens (key) with their score (value)
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* (see function definition for more info)
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*
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* Major Contributors
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* - Martin Dougiamas {@link http://moodle.com}
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* - Eloy Lafuente (stronk7) {@link http://contiento.com}
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* - Antonio Vicent {@link http://ludens.es}
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*
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* @package moodlecore
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* @copyright (C) 2001-3001 Eloy Lafuente (stronk7) {@link http://contiento.com}
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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/**
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* Some constants
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*/
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define ('MINIMUM_WORD_SIZE', 3); /// Minimum word size to index and search
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define ('MAXIMUM_WORD_SIZE', 50); /// Maximum word size to index and search
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define ('START_DELIM', "\xce\xa9\xc3\x91\xc3\x91"); // Use these (omega) and (ntilde) utf-8 combinations
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define ('CENTER_DELIM', "\xc3\x91\xce\xa9\xc3\x91"); // as safe delimiters (not puncuation nor usual) while
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define ('END_DELIM', "\xc3\x91\xc3\x91\xce\xa9"); // processing numbers ($join_numbers = false)
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/**
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* Matches Unicode character classes to exclude from the search index.
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*
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* See: http://www.unicode.org/Public/UNIDATA/UCD.html#General_Category_Values
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*
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* The index only contains the following character classes:
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* Lu Letter, Uppercase
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* Ll Letter, Lowercase
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* Lt Letter, Titlecase
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* Lo Letter, Other
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* Nd Number, Decimal Digit
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* No Number, Other
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*/
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define('PREG_CLASS_SEARCH_EXCLUDE',
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'\x{0}-\x{2f}\x{3a}-\x{40}\x{5b}-\x{60}\x{7b}-\x{bf}\x{d7}\x{f7}\x{2b0}-'.
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'\x{385}\x{387}\x{3f6}\x{482}-\x{489}\x{559}-\x{55f}\x{589}-\x{5c7}\x{5f3}-'.
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'\x{61f}\x{640}\x{64b}-\x{65e}\x{66a}-\x{66d}\x{670}\x{6d4}\x{6d6}-\x{6ed}'.
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'\x{6fd}\x{6fe}\x{700}-\x{70f}\x{711}\x{730}-\x{74a}\x{7a6}-\x{7b0}\x{901}-'.
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'\x{903}\x{93c}\x{93e}-\x{94d}\x{951}-\x{954}\x{962}-\x{965}\x{970}\x{981}-'.
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'\x{983}\x{9bc}\x{9be}-\x{9cd}\x{9d7}\x{9e2}\x{9e3}\x{9f2}-\x{a03}\x{a3c}-'.
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'\x{a4d}\x{a70}\x{a71}\x{a81}-\x{a83}\x{abc}\x{abe}-\x{acd}\x{ae2}\x{ae3}'.
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'\x{af1}-\x{b03}\x{b3c}\x{b3e}-\x{b57}\x{b70}\x{b82}\x{bbe}-\x{bd7}\x{bf0}-'.
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'\x{c03}\x{c3e}-\x{c56}\x{c82}\x{c83}\x{cbc}\x{cbe}-\x{cd6}\x{d02}\x{d03}'.
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'\x{d3e}-\x{d57}\x{d82}\x{d83}\x{dca}-\x{df4}\x{e31}\x{e34}-\x{e3f}\x{e46}-'.
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'\x{e4f}\x{e5a}\x{e5b}\x{eb1}\x{eb4}-\x{ebc}\x{ec6}-\x{ecd}\x{f01}-\x{f1f}'.
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'\x{f2a}-\x{f3f}\x{f71}-\x{f87}\x{f90}-\x{fd1}\x{102c}-\x{1039}\x{104a}-'.
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'\x{104f}\x{1056}-\x{1059}\x{10fb}\x{10fc}\x{135f}-\x{137c}\x{1390}-\x{1399}'.
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'\x{166d}\x{166e}\x{1680}\x{169b}\x{169c}\x{16eb}-\x{16f0}\x{1712}-\x{1714}'.
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'\x{1732}-\x{1736}\x{1752}\x{1753}\x{1772}\x{1773}\x{17b4}-\x{17db}\x{17dd}'.
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'\x{17f0}-\x{180e}\x{1843}\x{18a9}\x{1920}-\x{1945}\x{19b0}-\x{19c0}\x{19c8}'.
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'\x{19c9}\x{19de}-\x{19ff}\x{1a17}-\x{1a1f}\x{1d2c}-\x{1d61}\x{1d78}\x{1d9b}-'.
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'\x{1dc3}\x{1fbd}\x{1fbf}-\x{1fc1}\x{1fcd}-\x{1fcf}\x{1fdd}-\x{1fdf}\x{1fed}-'.
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'\x{1fef}\x{1ffd}-\x{2070}\x{2074}-\x{207e}\x{2080}-\x{2101}\x{2103}-\x{2106}'.
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'\x{2108}\x{2109}\x{2114}\x{2116}-\x{2118}\x{211e}-\x{2123}\x{2125}\x{2127}'.
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'\x{2129}\x{212e}\x{2132}\x{213a}\x{213b}\x{2140}-\x{2144}\x{214a}-\x{2b13}'.
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'\x{2ce5}-\x{2cff}\x{2d6f}\x{2e00}-\x{3005}\x{3007}-\x{303b}\x{303d}-\x{303f}'.
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'\x{3099}-\x{309e}\x{30a0}\x{30fb}-\x{30fe}\x{3190}-\x{319f}\x{31c0}-\x{31cf}'.
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'\x{3200}-\x{33ff}\x{4dc0}-\x{4dff}\x{a015}\x{a490}-\x{a716}\x{a802}\x{a806}'.
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'\x{a80b}\x{a823}-\x{a82b}\x{d800}-\x{f8ff}\x{fb1e}\x{fb29}\x{fd3e}\x{fd3f}'.
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'\x{fdfc}-\x{fe6b}\x{feff}-\x{ff0f}\x{ff1a}-\x{ff20}\x{ff3b}-\x{ff40}\x{ff5b}-'.
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'\x{ff65}\x{ff70}\x{ff9e}\x{ff9f}\x{ffe0}-\x{fffd}');
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/**
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* Matches all 'N' Unicode character classes (numbers)
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*/
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define('PREG_CLASS_NUMBERS',
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'\x{30}-\x{39}\x{b2}\x{b3}\x{b9}\x{bc}-\x{be}\x{660}-\x{669}\x{6f0}-\x{6f9}'.
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'\x{966}-\x{96f}\x{9e6}-\x{9ef}\x{9f4}-\x{9f9}\x{a66}-\x{a6f}\x{ae6}-\x{aef}'.
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'\x{b66}-\x{b6f}\x{be7}-\x{bf2}\x{c66}-\x{c6f}\x{ce6}-\x{cef}\x{d66}-\x{d6f}'.
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'\x{e50}-\x{e59}\x{ed0}-\x{ed9}\x{f20}-\x{f33}\x{1040}-\x{1049}\x{1369}-'.
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'\x{137c}\x{16ee}-\x{16f0}\x{17e0}-\x{17e9}\x{17f0}-\x{17f9}\x{1810}-\x{1819}'.
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'\x{1946}-\x{194f}\x{2070}\x{2074}-\x{2079}\x{2080}-\x{2089}\x{2153}-\x{2183}'.
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'\x{2460}-\x{249b}\x{24ea}-\x{24ff}\x{2776}-\x{2793}\x{3007}\x{3021}-\x{3029}'.
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'\x{3038}-\x{303a}\x{3192}-\x{3195}\x{3220}-\x{3229}\x{3251}-\x{325f}\x{3280}-'.
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'\x{3289}\x{32b1}-\x{32bf}\x{ff10}-\x{ff19}');
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/**
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* Matches all 'P' Unicode character classes (punctuation)
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*/
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define('PREG_CLASS_PUNCTUATION',
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'\x{21}-\x{23}\x{25}-\x{2a}\x{2c}-\x{2f}\x{3a}\x{3b}\x{3f}\x{40}\x{5b}-\x{5d}'.
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'\x{5f}\x{7b}\x{7d}\x{a1}\x{ab}\x{b7}\x{bb}\x{bf}\x{37e}\x{387}\x{55a}-\x{55f}'.
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'\x{589}\x{58a}\x{5be}\x{5c0}\x{5c3}\x{5f3}\x{5f4}\x{60c}\x{60d}\x{61b}\x{61f}'.
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'\x{66a}-\x{66d}\x{6d4}\x{700}-\x{70d}\x{964}\x{965}\x{970}\x{df4}\x{e4f}'.
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'\x{e5a}\x{e5b}\x{f04}-\x{f12}\x{f3a}-\x{f3d}\x{f85}\x{104a}-\x{104f}\x{10fb}'.
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'\x{1361}-\x{1368}\x{166d}\x{166e}\x{169b}\x{169c}\x{16eb}-\x{16ed}\x{1735}'.
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'\x{1736}\x{17d4}-\x{17d6}\x{17d8}-\x{17da}\x{1800}-\x{180a}\x{1944}\x{1945}'.
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'\x{2010}-\x{2027}\x{2030}-\x{2043}\x{2045}-\x{2051}\x{2053}\x{2054}\x{2057}'.
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'\x{207d}\x{207e}\x{208d}\x{208e}\x{2329}\x{232a}\x{23b4}-\x{23b6}\x{2768}-'.
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'\x{2775}\x{27e6}-\x{27eb}\x{2983}-\x{2998}\x{29d8}-\x{29db}\x{29fc}\x{29fd}'.
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'\x{3001}-\x{3003}\x{3008}-\x{3011}\x{3014}-\x{301f}\x{3030}\x{303d}\x{30a0}'.
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'\x{30fb}\x{fd3e}\x{fd3f}\x{fe30}-\x{fe52}\x{fe54}-\x{fe61}\x{fe63}\x{fe68}'.
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'\x{fe6a}\x{fe6b}\x{ff01}-\x{ff03}\x{ff05}-\x{ff0a}\x{ff0c}-\x{ff0f}\x{ff1a}'.
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'\x{ff1b}\x{ff1f}\x{ff20}\x{ff3b}-\x{ff3d}\x{ff3f}\x{ff5b}\x{ff5d}\x{ff5f}-'.
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'\x{ff65}');
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/**
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* Matches all CJK characters that are candidates for auto-splitting
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* (Chinese, Japanese, Korean).
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* Contains kana and BMP ideographs.
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*/
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define('PREG_CLASS_CJK', '\x{3041}-\x{30ff}\x{31f0}-\x{31ff}\x{3400}-\x{4db5}'.
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'\x{4e00}-\x{9fbb}\x{f900}-\x{fad9}');
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/**
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* This function process the text passed at input, extracting all the tokens
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* and scoring each one based in their number of ocurrences and relation with
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* some well-known html tags
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*
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* @param string $text the text to be tokenised.
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* @param array $stop_words array of utf-8 words than can be ignored in
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* the text being processed. There are some cool lists of
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* stop words at http://snowball.tartarus.org/
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* @param boolean $overlap_cjk option to split CJK text into some overlapping
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* tokens is order to allow them to be searched. Useful to build
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* indexes and search systems.
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* @param boolean $join_numbers option to join in one unique token sequences of numbers
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* separated by puntuaction chars. Useful to build indexes and
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* search systems.
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* @return array one sorted array of tokens, with tokens being the keys and scores in the values.
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*/
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function tokenise_text($text, $stop_words = array(), $overlap_cjk = false, $join_numbers = false) {
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// Multipliers for scores of words inside certain HTML tags.
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// Note: 'a' must be included for link ranking to work.
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$tags = array('h1' => 25,
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'h2' => 18,
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'h3' => 15,
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'h4' => 12,
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'h5' => 9,
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'h6' => 6,
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'u' => 3,
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'b' => 3,
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'i' => 3,
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'strong' => 3,
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'em' => 3,
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'a' => 10);
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// Strip off all ignored tags to speed up processing, but insert space before/after
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// them to keep word boundaries.
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$text = str_replace(array('<', '>'), array(' <', '> '), $text);
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$text = strip_tags($text, '<'. implode('><', array_keys($tags)) .'>');
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// Split HTML tags from plain text.
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$split = preg_split('/\s*<([^>]+?)>\s*/', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
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// Note: PHP ensures the array consists of alternating delimiters and literals
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// and begins and ends with a literal (inserting $null as required).
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$tag = FALSE; // Odd/even counter. Tag or no tag.
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$score = 1; // Starting score per word
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$accum = ' '; // Accumulator for cleaned up data
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$tagstack = array(); // Stack with open tags
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$tagwords = 0; // Counter for consecutive words
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$focus = 1; // Focus state
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$results = array(0 => array()); // Accumulator for words for index
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foreach ($split as $value) {
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if ($tag) {
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// Increase or decrease score per word based on tag
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list($tagname) = explode(' ', $value, 2);
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$tagname = core_text::strtolower($tagname);
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// Closing or opening tag?
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if ($tagname[0] == '/') {
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$tagname = substr($tagname, 1);
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// If we encounter unexpected tags, reset score to avoid incorrect boosting.
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if (!count($tagstack) || $tagstack[0] != $tagname) {
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$tagstack = array();
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$score = 1;
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}
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else {
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// Remove from tag stack and decrement score
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$score = max(1, $score - $tags[array_shift($tagstack)]);
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}
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}
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else {
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if (isset($tagstack[0]) && $tagstack[0] == $tagname) {
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// None of the tags we look for make sense when nested identically.
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// If they are, it's probably broken HTML.
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$tagstack = array();
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$score = 1;
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}
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else {
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// Add to open tag stack and increment score
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array_unshift($tagstack, $tagname);
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$score += $tags[$tagname];
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}
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}
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// A tag change occurred, reset counter.
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$tagwords = 0;
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}
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else {
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// Note: use of PREG_SPLIT_DELIM_CAPTURE above will introduce empty values
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if ($value != '') {
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$words = tokenise_split($value, $stop_words, $overlap_cjk, $join_numbers);
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foreach ($words as $word) {
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// Add word to accumulator
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$accum .= $word .' ';
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$num = is_numeric($word);
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// Check word length
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if ($num || core_text::strlen($word) >= MINIMUM_WORD_SIZE) {
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// Normalize numbers
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if ($num && $join_numbers) {
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$word = (int)ltrim($word, '-0');
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}
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if (!isset($results[0][$word])) {
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$results[0][$word] = 0;
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}
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$results[0][$word] += $score * $focus;
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// Focus is a decaying value in terms of the amount of unique words up to this point.
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// From 100 words and more, it decays, to e.g. 0.5 at 500 words and 0.3 at 1000 words.
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$focus = min(1, .01 + 3.5 / (2 + count($results[0]) * .015));
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}
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$tagwords++;
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// Too many words inside a single tag probably mean a tag was accidentally left open.
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if (count($tagstack) && $tagwords >= 15) {
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$tagstack = array();
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$score = 1;
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}
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}
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}
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}
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$tag = !$tag;
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}
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$res = array();
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if (isset($results[0]) && count($results[0]) > 0) {
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$res = $results[0];
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arsort($res, SORT_NUMERIC);
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}
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return $res;
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}
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///
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/// Some helper functions (should be considered private)
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///
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/**
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* Splits a string into tokens
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*/
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function tokenise_split($text, $stop_words, $overlap_cjk, $join_numbers) {
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static $last = NULL;
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static $lastsplit = NULL;
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if ($last == $text) {
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return $lastsplit;
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}
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// Process words
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$text = tokenise_simplify($text, $overlap_cjk, $join_numbers);
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$words = explode(' ', $text);
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// Limit word length to 50
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array_walk($words, 'tokenise_truncate_word');
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// We have stop words, apply them
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if (is_array($stop_words) && !empty($stop_words)) {
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// Normalise them
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$simp_stop_words = explode(' ', tokenise_simplify(implode(' ', $stop_words), $overlap_cjk, $join_numbers));
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// Extract from the list
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$words = array_diff($words, $simp_stop_words);
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}
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// Save last keyword result
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$last = $text;
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$lastsplit = $words;
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return $words;
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}
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/**
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* Simplifies a string according to indexing rules.
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*/
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function tokenise_simplify($text, $overlap_cjk, $join_numbers) {
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// Decode entities to UTF-8
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$text = core_text::entities_to_utf8($text, true);
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// Lowercase
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$text = core_text::strtolower($text);
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// Simple CJK handling
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if ($overlap_cjk) {
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$text = preg_replace_callback('/['. PREG_CLASS_CJK .']+/u', 'tokenise_expand_cjk', $text);
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}
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// To improve searching for numerical data such as dates, IP addresses
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// or version numbers, we consider a group of numerical characters
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// separated only by punctuation characters to be one piece.
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// This also means that searching for e.g. '20/03/1984' also returns
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// results with '20-03-1984' in them.
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// Readable regexp: ([number]+)[punctuation]+(?=[number])
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if ($join_numbers) {
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$text = preg_replace('/(['. PREG_CLASS_NUMBERS .']+)['. PREG_CLASS_PUNCTUATION .']+(?=['. PREG_CLASS_NUMBERS .'])/u', '\1', $text);
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} else {
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// Keep all the detected numbers+punctuation in a safe place in order to restore them later
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preg_match_all('/['. PREG_CLASS_NUMBERS .']+['. PREG_CLASS_PUNCTUATION . PREG_CLASS_NUMBERS .']+/u', $text, $foundseqs);
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$storedseqs = array();
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foreach (array_unique($foundseqs[0]) as $ntkey => $value) {
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$prefix = (string)(count($storedseqs) + 1);
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$storedseqs[START_DELIM.$prefix.CENTER_DELIM.$ntkey.END_DELIM] = $value;
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}
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if (!empty($storedseqs)) {
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$text = str_replace($storedseqs, array_keys($storedseqs), $text);
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}
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}
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// The dot, underscore and dash are simply removed. This allows meaningful
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// search behaviour with acronyms and URLs.
|
|
$text = preg_replace('/[._-]+/', '', $text);
|
|
|
|
// With the exception of the rules above, we consider all punctuation,
|
|
// marks, spacers, etc, to be a word boundary.
|
|
$text = preg_replace('/['. PREG_CLASS_SEARCH_EXCLUDE .']+/u', ' ', $text);
|
|
|
|
// Restore, if not joining numbers, recover the original strings
|
|
if (!$join_numbers) {
|
|
if (!empty($storedseqs)) {
|
|
$text = str_replace(array_keys($storedseqs), $storedseqs, $text);
|
|
}
|
|
}
|
|
|
|
return $text;
|
|
}
|
|
|
|
/**
|
|
* Basic CJK tokeniser. Simply splits a string into consecutive, overlapping
|
|
* sequences of characters (MINIMUM_WORD_SIZE long).
|
|
*/
|
|
function tokenise_expand_cjk($matches) {
|
|
|
|
$str = $matches[0];
|
|
$l = core_text::strlen($str);
|
|
// Passthrough short words
|
|
if ($l <= MINIMUM_WORD_SIZE) {
|
|
return ' '. $str .' ';
|
|
}
|
|
$tokens = ' ';
|
|
// FIFO queue of characters
|
|
$chars = array();
|
|
// Begin loop
|
|
for ($i = 0; $i < $l; ++$i) {
|
|
// Grab next character
|
|
$current = core_text::substr($str, 0, 1);
|
|
$str = substr($str, strlen($current));
|
|
$chars[] = $current;
|
|
if ($i >= MINIMUM_WORD_SIZE - 1) {
|
|
$tokens .= implode('', $chars) .' ';
|
|
array_shift($chars);
|
|
}
|
|
}
|
|
return $tokens;
|
|
}
|
|
|
|
/**
|
|
* Helper function for array_walk in search_index_split.
|
|
* Truncates one string (token) to MAXIMUM_WORD_SIZE
|
|
*/
|
|
function tokenise_truncate_word(&$text) {
|
|
|
|
$text = core_text::substr($text, 0, MAXIMUM_WORD_SIZE);
|
|
}
|
|
|