rebase from live enviornment

wp/plugins/relevanssi-premium/premium/class-relevanssi-spellcorrector.php

@@ -0,0 +1,221 @@
+<?php
+/**
+ * /premium/class-spellcorrector.php
+ *
+ * @package Relevanssi_Premium
+ * @author  Felipe Ribeiro <felipernb@gmail.com> with modifications by Mikko Saari
+ * @see     https://www.relevanssi.com/
+ */
+
+/*
+***************************************************************************
+*   Copyright (C) 2008 by Felipe Ribeiro                                  *
+*   felipernb@gmail.com                                                   *
+*   http://www.feliperibeiro.com                                          *
+*                                                                         *
+*   Permission is hereby granted, free of charge, to any person obtaining *
+*   a copy of this software and associated documentation files (the       *
+*   "Software"), to deal in the Software without restriction, including   *
+*   without limitation the rights to use, copy, modify, merge, publish,   *
+*   distribute, sublicense, and/or sell copies of the Software, and to    *
+*   permit persons to whom the Software is furnished to do so, subject to *
+*   the following conditions:                                             *
+*                                                                         *
+*   The above copyright notice and this permission notice shall be        *
+*   included in all copies or substantial portions of the Software.       *
+*                                                                         *
+*   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       *
+*   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    *
+*   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*
+*   IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR     *
+*   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
+*   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
+*   OTHER DEALINGS IN THE SOFTWARE.                                       *
+***************************************************************************
+*/
+
+/**
+ * Spell correcting feature.
+ *
+ * This class implements the Spell correcting feature, useful for the
+ * "Did you mean" functionality on the search engine. Using a dictionary of
+ * words extracted from the product catalog.
+ *
+ * Based on the concepts of Peter Norvig: http://norvig.com/spell-correct.html
+ *
+ * @author Felipe Ribeiro <felipernb@gmail.com>
+ * @date September 18th, 2008
+ */
+class Relevanssi_SpellCorrector {
+	/**
+	 * Dictionary of words.
+	 *
+	 * @var array $dictionary Array of words, containing the dictionary.
+	 */
+	private static $dictionary;
+
+	/**
+	 * Reads a text and extracts the list of words.
+	 *
+	 * @param string $text Source text for the words.
+	 * @return array The list of words
+	 */
+	private static function words( $text ) {
+		$matches = array();
+		$text    = relevanssi_strtolower( $text );
+		preg_match_all( '/[a-z]+/', $text, $matches );
+		return $matches[0];
+	}
+
+	/**
+	 * Generates a list of possible "disturbances" on the passed string.
+	 *
+	 * @param string $word Word to disturb.
+	 *
+	 * @return array A list of variations.
+	 */
+	private static function edits1( $word ) {
+		/**
+		 * Filters the alphabet used for Did you mean suggestions.
+		 *
+		 * In order to use the Did you mean suggestions with non-Latin alphabets
+		 * (or even European languages with a wider range of characters than
+		 * English), Relevanssi needs to be provided with the alphabet used.
+		 *
+		 * @param string A string containing the alphabet as a string of
+		 * characters without spaces.
+		 */
+		$alphabet = apply_filters(
+			'relevanssi_didyoumean_alphabet',
+			'abcdefghijklmnopqrstuvwxyzäöåü'
+		);
+		$alphabet = preg_split( '/(?<!^)(?!$)/u', $alphabet );
+		$n        = relevanssi_strlen( $word );
+		$edits    = array();
+
+		$substr_function = 'substr';
+		if ( function_exists( 'mb_substr' ) ) {
+			$substr_function = 'mb_substr';
+		}
+		for ( $i = 0; $i < $n; $i++ ) {
+			// Removing one letter.
+			$edits[] = call_user_func( $substr_function, $word, 0, $i )
+				. call_user_func( $substr_function, $word, $i + 1 );
+
+			// Substituting one letter.
+			foreach ( $alphabet as $c ) {
+				$edits[] = call_user_func( $substr_function, $word, 0, $i )
+					. $c . call_user_func( $substr_function, $word, $i + 1 );
+			}
+		}
+		for ( $i = 0; $i < $n - 1; $i++ ) {
+			// Swapping character order.
+			$edits[] = call_user_func( $substr_function, $word, 0, $i )
+				. $word[ $i + 1 ] . $word[ $i ]
+				. call_user_func( $substr_function, $word, $i + 2 );
+		}
+
+		// Inserting one character.
+		for ( $i = 0; $i < $n + 1; $i++ ) {
+			foreach ( $alphabet as $c ) {
+				$edits[] = call_user_func( $substr_function, $word, 0, $i )
+					. $c . call_user_func( $substr_function, $word, $i );
+			}
+		}
+
+		return $edits;
+	}
+
+	/**
+	 * Generate possible "disturbances" in a second level that exist on the
+	 * dictionary.
+	 *
+	 * @param string $word Word to disturb.
+	 *
+	 * @return array Known disturbances.
+	 */
+	private static function known_edits2( $word ) {
+		$known = array();
+		foreach ( self::edits1( $word ) as $e1 ) {
+			foreach ( self::edits1( $e1 ) as $e2 ) {
+				if ( array_key_exists( $e2, self::$dictionary ) ) {
+					$known[] = $e2;
+				}
+			}
+		}
+		return $known;
+	}
+
+	/**
+	 * Given a list of words, returns the subset that is present on the
+	 * dictionary.
+	 *
+	 * @param array $words Array of words to check.
+	 * @return array Words that are in the dictionary.
+	 */
+	private static function known( array $words ) {
+		$known = array();
+		foreach ( $words as $w ) {
+			if ( array_key_exists( $w, self::$dictionary ) ) {
+				$known[] = $w;
+			}
+		}
+		return $known;
+	}
+
+	/**
+	 * Corrects the word.
+	 *
+	 * Returns the word that is present on the dictionary that is the most
+	 * similar (and the most relevant) to the word passed as parameter.
+	 *
+	 * @param string $word Word to correct.
+	 *
+	 * @return string Correction suggestion, null if nothing found.
+	 */
+	public static function correct( $word ) {
+		$word = trim( $word );
+
+		if ( empty( $word ) ) {
+			return null;
+		}
+
+		$word = relevanssi_strtolower( $word );
+
+		if ( empty( self::$dictionary ) ) {
+			self::$dictionary = relevanssi_get_words();
+		}
+
+		$candidates = array();
+		if ( self::known( array( $word ) ) ) {
+			// Word is in the dictionary. It's fine.
+			return true;
+		} else {
+			$tmp_candidates = self::known( self::edits1( $word ) );
+			if ( ! empty( $tmp_candidates ) ) {
+				foreach ( $tmp_candidates as $candidate ) {
+					$candidates[] = $candidate;
+				}
+			} else {
+				$tmp_candidates = self::known_edits2( $word );
+				if ( ! empty( $tmp_candidates ) ) {
+					foreach ( $tmp_candidates as $candidate ) {
+						$candidates[] = $candidate;
+					}
+				} else {
+					return null;
+				}
+			}
+		}
+		$max = 0;
+
+		foreach ( $candidates as $c ) {
+			$value = self::$dictionary[ $c ];
+			if ( $value > $max ) {
+				$max  = $value;
+				$word = $c;
+			}
+		}
+		return $word;
+	}
+}