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