Cross-language language name search

Implementation of Also Written As language name
search algorithm.
See http://etherpad.wikimedia.org/l10n-uls-language-search

Change-Id: Iff84408c531b650a44d031b63d5c823737cceafc

data/LanguageNameSearch.php

@@ -0,0 +1,80 @@
+<?php
+/**
+ * Cross-Language Language name search
+ *
+ * Copyright (C) 2012 Alolita Sharma, Amir Aharoni, Arun Ganesh, Brandon Harris,
+ * Niklas Laxström, Pau Giner, Santhosh Thottingal, Siebrand Mazeland and other
+ * contributors. See CREDITS for a list.
+ *
+ * UniversalLanguageSelector is dual licensed GPLv2 or later and MIT. You don't
+ * have to do anything special to choose one license or the other and you don't
+ * have to notify anyone which license you are using. You are free to use
+ * UniversalLanguageSelector in commercial projects as long as the copyright
+ * header is left intact. See files GPL-LICENSE and MIT-LICENSE for details.
+ *
+ * @file
+ * @ingroup Extensions
+ * @licence GNU General Public Licence 2.0 or later
+ * @licence MIT License
+ */
+class LanguageNameSearch {
+	static $languagenames;
+	public function init() {
+		self::$languagenames = unserialize( file_get_contents( __DIR__ . '/langnames.ser' ) );
+	}
+
+	public static function search( $searchKey ) {
+		$results = array();
+		if ( self::$languagenames === null ) {
+			self::init();
+		}
+		$bucket = self::$languagenames[self::getIndex( $searchKey )];
+		foreach ( $bucket as $name => $code ) {
+			// Prefix search
+			if ( strpos( $name, $searchKey, 0 ) === 0 ) {
+				$results[$code] = $name;
+			}
+		}
+		return $results;
+	}
+	public static function getIndex( $name ) {
+		$codepoint = self::getCodepoint( $name );
+		if ( $codepoint < 1000 ) {
+			$bucket = $codepoint;
+		} else {
+			$bucket = $codepoint % 1000;
+		}
+		if ( !isset( $buckets[$bucket] ) ) {
+			$buckets[$bucket] = array();
+		}
+		return $bucket;
+	}
+	/**
+	 * Get the code point of first letter of string
+	 *
+	 * @return integer Code point of first letter of string
+	 */
+	static function getCodepoint( $str ) {
+		$unicode = array();
+		$values = array();
+		$lookingFor = 1;
+		for ( $i = 0; $i < strlen( $str ); $i++ ) {
+			$thisValue = ord( $str[$i] );
+			if ( $thisValue < 128 ) {
+				return $thisValue;
+			} else { // Codepoints larger than 127 are represented by multi-byte sequences,
+				if ( count( $values ) === 0 ) {
+					// 224 is the lowest non-overlong-encoded codepoint.
+					$lookingFor = ( $thisValue < 224 ) ? 2 : 3;
+				}
+				$values[] = $thisValue;
+				if ( count( $values ) === $lookingFor ) {
+					// Refer http://en.wikipedia.org/wiki/UTF-8#Description
+					$number = ( $lookingFor === 3 ) ? ( ( $values[0] % 16 ) * 4096 ) + ( ( $values[1] % 64 ) * 64 ) + ( $values[2] % 64 ) : ( ( $values[0] % 32 ) * 64 ) + ( $values[
+1] % 64 );
+					return $number;
+				}
+			}
+		}
+	}
+}