Merge branch 'archwiki'

Conflicts:
	extensions/FluxBBAuthPlugin.php
	extensions/SyntaxHighlight_GeSHi/README
	extensions/SyntaxHighlight_GeSHi/SyntaxHighlight_GeSHi.class.php
	extensions/SyntaxHighlight_GeSHi/SyntaxHighlight_GeSHi.i18n.php
	extensions/SyntaxHighlight_GeSHi/SyntaxHighlight_GeSHi.php
	extensions/SyntaxHighlight_GeSHi/geshi/docs/CHANGES
	extensions/SyntaxHighlight_GeSHi/geshi/docs/THANKS
	extensions/SyntaxHighlight_GeSHi/geshi/docs/TODO
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractClass.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractClass_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractMethod.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractPrivateClass.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractPrivateClass_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/AbstractPrivateMethod.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Class.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Class_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Constant.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Constructor.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Destructor.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Function.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Global.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/I.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Index.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Interface.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Interface_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/L.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Lminus.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Lplus.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Method.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Page.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Page_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/PrivateClass.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/PrivateClass_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/PrivateMethod.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/PrivateVariable.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/StaticMethod.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/StaticVariable.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/T.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Tminus.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Tplus.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/Variable.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/blank.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/class_folder.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/file.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/folder.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/function_folder.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/next_button.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/next_button_disabled.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/package.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/package_folder.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/previous_button.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/previous_button_disabled.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/private_class_logo.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/tutorial.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/tutorial_folder.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/api/media/images/up_button.png
	extensions/SyntaxHighlight_GeSHi/geshi/docs/geshi-doc.html
	extensions/SyntaxHighlight_GeSHi/geshi/docs/geshi-doc.txt
	extensions/SyntaxHighlight_GeSHi/geshi/geshi.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/4cs.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/6502acme.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/6502kickass.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/6502tasm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/68000devpac.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/abap.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/actionscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/actionscript3.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ada.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/algol68.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/apache.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/applescript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/apt_sources.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/asm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/asp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/autoconf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/autohotkey.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/autoit.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/avisynth.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/awk.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/bascomavr.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/bash.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/basic4gl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/bf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/bibtex.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/blitzbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/bnf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/boo.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/c.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/c_loadrunner.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/c_mac.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/caddcl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cadlisp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cfdg.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cfm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/chaiscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cil.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/clojure.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cmake.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cobol.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/coffeescript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cpp-qt.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cpp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/csharp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/css.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/cuesheet.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/d.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/dcs.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/delphi.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/diff.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/div.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/dos.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/dot.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/e.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ecmascript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/eiffel.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/email.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/epc.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/erlang.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/euphoria.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/f1.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/falcon.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/fo.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/fortran.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/freebasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/fsharp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gambas.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gdb.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/genero.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/genie.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gettext.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/glsl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gml.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gnuplot.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/go.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/groovy.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/gwbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/haskell.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/hicest.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/hq9plus.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/html4strict.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/html5.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/icon.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/idl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ini.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/inno.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/intercal.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/io.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/j.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/java.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/java5.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/javascript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/jquery.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/kixtart.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/klonec.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/klonecpp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/latex.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lb.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lisp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/llvm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/locobasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/logtalk.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lolcode.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lotusformulas.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lotusscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lsl2.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/lua.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/m68k.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/magiksf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/make.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mapbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/matlab.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mirc.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mmix.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/modula2.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/modula3.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mpasm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mxml.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/mysql.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/newlisp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/nsis.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oberon2.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/objc.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/objeck.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ocaml-brief.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ocaml.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oobas.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oracle11.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oracle8.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oxygene.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/oz.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pascal.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pcre.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/per.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/perl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/perl6.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/php-brief.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/php.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pic16.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pike.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pixelbender.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pli.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/plsql.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/postgresql.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/povray.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/powerbuilder.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/powershell.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/proftpd.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/progress.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/prolog.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/properties.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/providex.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/purebasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/pycon.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/python.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/q.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/qbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/rails.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/rebol.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/reg.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/robots.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/rpmspec.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/rsplus.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/ruby.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/sas.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/scala.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/scheme.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/scilab.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/sdlbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/smalltalk.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/smarty.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/sql.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/systemverilog.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/tcl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/teraterm.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/text.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/thinbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/tsql.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/typoscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/unicon.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/uscript.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/vala.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/vb.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/vbnet.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/verilog.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/vhdl.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/vim.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/visualfoxpro.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/visualprolog.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/whitespace.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/whois.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/winbatch.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/xbasic.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/xml.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/xorg_conf.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/xpp.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/yaml.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/z80.php
	extensions/SyntaxHighlight_GeSHi/geshi/geshi/zxbasic.php

1 files changed, 133 insertions, 43 deletions

diff --git a/includes/StringUtils.php b/includes/StringUtils.php
index 43275a66..c1545e6e 100644
--- a/includes/StringUtils.php
+++ b/includes/StringUtils.php
@@ -24,6 +24,92 @@
  * A collection of static methods to play with strings.
  */
 class StringUtils {
+
+	/**
+	 * Test whether a string is valid UTF-8.
+	 *
+	 * The function check for invalid byte sequences, overlong encoding but
+	 * not for different normalisations.
+	 *
+	 * This relies internally on the mbstring function mb_check_encoding()
+	 * hardcoded to check against UTF-8. Whenever the function is not available
+	 * we fallback to a pure PHP implementation. Setting $disableMbstring to
+	 * true will skip the use of mb_check_encoding, this is mostly intended for
+	 * unit testing our internal implementation.
+	 *
+	 * @since 1.21
+	 * @note In MediaWiki 1.21, this function did not provide proper UTF-8 validation.
+	 * In particular, the pure PHP code path did not in fact check for overlong forms.
+	 * Beware of this when backporting code to that version of MediaWiki.
+	 *
+	 * @param string $value String to check
+	 * @param boolean $disableMbstring Whether to use the pure PHP
+	 * implementation instead of trying mb_check_encoding. Intended for unit
+	 * testing. Default: false
+	 *
+	 * @return boolean Whether the given $value is a valid UTF-8 encoded string
+	 */
+	static function isUtf8( $value, $disableMbstring = false ) {
+		$value = (string)$value;
+
+		// If the mbstring extension is loaded, use it. However, before PHP 5.4, values above
+		// U+10FFFF are incorrectly allowed, so we have to check for them separately.
+		if ( !$disableMbstring && function_exists( 'mb_check_encoding' ) ) {
+			static $newPHP;
+			if ( $newPHP === null ) {
+				$newPHP = !mb_check_encoding( "\xf4\x90\x80\x80", 'UTF-8' );
+			}
+
+			return mb_check_encoding( $value, 'UTF-8' ) &&
+				( $newPHP || preg_match( "/\xf4[\x90-\xbf]|[\xf5-\xff]/S", $value ) === 0 );
+		}
+
+		if ( preg_match( "/[\x80-\xff]/S", $value ) === 0 ) {
+			// String contains only ASCII characters, has to be valid
+			return true;
+		}
+
+		// PCRE implements repetition using recursion; to avoid a stack overflow (and segfault)
+		// for large input, we check for invalid sequences (<= 5 bytes) rather than valid
+		// sequences, which can be as long as the input string is. Multiple short regexes are
+		// used rather than a single long regex for performance.
+		static $regexes;
+		if ( $regexes === null ) {
+			$cont = "[\x80-\xbf]";
+			$after = "(?!$cont)"; // "(?:[^\x80-\xbf]|$)" would work here
+			$regexes = array(
+				// Continuation byte at the start
+				"/^$cont/",
+
+				// ASCII byte followed by a continuation byte
+				"/[\\x00-\x7f]$cont/S",
+
+				// Illegal byte
+				"/[\xc0\xc1\xf5-\xff]/S",
+
+				// Invalid 2-byte sequence, or valid one then an extra continuation byte
+				"/[\xc2-\xdf](?!$cont$after)/S",
+
+				// Invalid 3-byte sequence, or valid one then an extra continuation byte
+				"/\xe0(?![\xa0-\xbf]$cont$after)/",
+				"/[\xe1-\xec\xee\xef](?!$cont{2}$after)/S",
+				"/\xed(?![\x80-\x9f]$cont$after)/",
+
+				// Invalid 4-byte sequence, or valid one then an extra continuation byte
+				"/\xf0(?![\x90-\xbf]$cont{2}$after)/",
+				"/[\xf1-\xf3](?!$cont{3}$after)/S",
+				"/\xf4(?![\x80-\x8f]$cont{2}$after)/",
+			);
+		}
+
+		foreach ( $regexes as $regex ) {
+			if ( preg_match( $regex, $value ) !== 0 ) {
+				return false;
+			}
+		}
+		return true;
+	}
+
 	/**
 	 * Perform an operation equivalent to
 	 *
@@ -65,16 +151,16 @@ class StringUtils {
 	 * memory. The delimiters are literal strings, not regular expressions.
 	 *
 	 * If the start delimiter ends with an initial substring of the end delimiter,
-	 * e.g. in the case of C-style comments, the behaviour differs from the model
+	 * e.g. in the case of C-style comments, the behavior differs from the model
 	 * regex. In this implementation, the end must share no characters with the
 	 * start, so e.g. /*\/ is not considered to be both the start and end of a
 	 * comment. /*\/xy/*\/ is considered to be a single comment with contents /xy/.
 	 *
-	 * @param $startDelim String: start delimiter
-	 * @param $endDelim String: end delimiter
+	 * @param string $startDelim start delimiter
+	 * @param string $endDelim end delimiter
 	 * @param $callback Callback: function to call on each match
 	 * @param $subject String
-	 * @param $flags String: regular expression flags
+	 * @param string $flags regular expression flags
 	 * @throws MWException
 	 * @return string
 	 */
@@ -90,12 +176,12 @@ class StringUtils {
 		$m = array();
 
 		while ( $inputPos < strlen( $subject ) &&
-		  preg_match( "!($encStart)|($encEnd)!S$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) )
+			preg_match( "!($encStart)|($encEnd)!S$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) )
 		{
 			$tokenOffset = $m[0][1];
 			if ( $m[1][0] != '' ) {
 				if ( $foundStart &&
-				  $strcmp( $endDelim, substr( $subject, $tokenOffset, $endLength ) ) == 0 )
+					$strcmp( $endDelim, substr( $subject, $tokenOffset, $endLength ) ) == 0 )
 				{
 					# An end match is present at the same location
 					$tokenType = 'end';
@@ -155,12 +241,12 @@ class StringUtils {
 	 *
 	 *   preg_replace( "!$startDelim(.*)$endDelim!$flags", $replace, $subject )
 	 *
-	 * @param $startDelim String: start delimiter regular expression
-	 * @param $endDelim String: end delimiter regular expression
-	 * @param $replace String: replacement string. May contain $1, which will be
+	 * @param string $startDelim start delimiter regular expression
+	 * @param string $endDelim end delimiter regular expression
+	 * @param string $replace replacement string. May contain $1, which will be
 	 *                 replaced by the text between the delimiters
-	 * @param $subject String to search
-	 * @param $flags String: regular expression flags
+	 * @param string $subject to search
+	 * @param string $flags regular expression flags
 	 * @return String: The string with the matches replaced
 	 */
 	static function delimiterReplace( $startDelim, $endDelim, $replace, $subject, $flags = '' ) {
@@ -172,8 +258,8 @@ class StringUtils {
 	/**
 	 * More or less "markup-safe" explode()
 	 * Ignores any instances of the separator inside <...>
-	 * @param $separator String
-	 * @param $text String
+	 * @param string $separator
+	 * @param string $text
 	 * @return array
 	 */
 	static function explodeMarkup( $separator, $text ) {
@@ -188,7 +274,7 @@ class StringUtils {
 
 		// Explode, then put the replaced separators back in
 		$items = explode( $separator, $cleaned );
-		foreach( $items as $i => $str ) {
+		foreach ( $items as $i => $str ) {
 			$items[$i] = str_replace( $placeholder, $separator, $str );
 		}
 
@@ -199,8 +285,8 @@ class StringUtils {
 	 * Escape a string to make it suitable for inclusion in a preg_replace()
 	 * replacement parameter.
 	 *
-	 * @param $string String
-	 * @return String
+	 * @param string $string
+	 * @return string
 	 */
 	static function escapeRegexReplacement( $string ) {
 		$string = str_replace( '\\', '\\\\', $string );
@@ -211,8 +297,8 @@ class StringUtils {
 	/**
 	 * Workalike for explode() with limited memory usage.
 	 * Returns an Iterator
-	 * @param $separator
-	 * @param $subject
+	 * @param string $separator
+	 * @param string $subject
 	 * @return ArrayIterator|ExplodeIterator
 	 */
 	static function explode( $separator, $subject ) {
@@ -245,14 +331,14 @@ class RegexlikeReplacer extends Replacer {
 	var $r;
 
 	/**
-	 * @param $r string
+	 * @param string $r
 	 */
 	function __construct( $r ) {
 		$this->r = $r;
 	}
 
 	/**
-	 * @param $matches array
+	 * @param array $matches
 	 * @return string
 	 */
 	function replace( $matches ) {
@@ -273,7 +359,7 @@ class DoubleReplacer extends Replacer {
 	/**
 	 * @param $from
 	 * @param $to
-	 * @param $index int
+	 * @param int $index
 	 */
 	function __construct( $from, $to, $index = 0 ) {
 		$this->from = $from;
@@ -282,7 +368,7 @@ class DoubleReplacer extends Replacer {
 	}
 
 	/**
-	 * @param $matches array
+	 * @param array $matches
 	 * @return mixed
 	 */
 	function replace( $matches ) {
@@ -298,7 +384,7 @@ class HashtableReplacer extends Replacer {
 
 	/**
 	 * @param $table
-	 * @param $index int
+	 * @param int $index
 	 */
 	function __construct( $table, $index = 0 ) {
 		$this->table = $table;
@@ -306,7 +392,7 @@ class HashtableReplacer extends Replacer {
 	}
 
 	/**
-	 * @param $matches array
+	 * @param array $matches
 	 * @return mixed
 	 */
 	function replace( $matches ) {
@@ -344,6 +430,7 @@ class ReplacementArray {
 
 	/**
 	 * Set the whole replacement array at once
+	 * @param array $data
 	 */
 	function setArray( $data ) {
 		$this->data = $data;
@@ -359,8 +446,8 @@ class ReplacementArray {
 
 	/**
 	 * Set an element of the replacement array
-	 * @param $from string
-	 * @param $to stromg
+	 * @param string $from
+	 * @param string $to
 	 */
 	function setPair( $from, $to ) {
 		$this->data[$from] = $to;
@@ -368,7 +455,7 @@ class ReplacementArray {
 	}
 
 	/**
-	 * @param $data array
+	 * @param array $data
 	 */
 	function mergeArray( $data ) {
 		$this->data = array_merge( $this->data, $data );
@@ -376,7 +463,7 @@ class ReplacementArray {
 	}
 
 	/**
-	 * @param $other
+	 * @param ReplacementArray $other
 	 */
 	function merge( $other ) {
 		$this->data = array_merge( $this->data, $other->data );
@@ -384,39 +471,39 @@ class ReplacementArray {
 	}
 
 	/**
-	 * @param $from string
+	 * @param string $from
 	 */
 	function removePair( $from ) {
-		unset($this->data[$from]);
+		unset( $this->data[$from] );
 		$this->fss = false;
 	}
 
 	/**
-	 * @param $data array
+	 * @param array $data
 	 */
 	function removeArray( $data ) {
-		foreach( $data as $from => $to ) {
+		foreach ( $data as $from => $to ) {
 			$this->removePair( $from );
 		}
 		$this->fss = false;
 	}
 
 	/**
-	 * @param $subject string
+	 * @param string $subject
 	 * @return string
 	 */
 	function replace( $subject ) {
 		if ( function_exists( 'fss_prep_replace' ) ) {
-			wfProfileIn( __METHOD__.'-fss' );
+			wfProfileIn( __METHOD__ . '-fss' );
 			if ( $this->fss === false ) {
 				$this->fss = fss_prep_replace( $this->data );
 			}
 			$result = fss_exec_replace( $this->fss, $subject );
-			wfProfileOut( __METHOD__.'-fss' );
+			wfProfileOut( __METHOD__ . '-fss' );
 		} else {
-			wfProfileIn( __METHOD__.'-strtr' );
+			wfProfileIn( __METHOD__ . '-strtr' );
 			$result = strtr( $subject, $this->data );
-			wfProfileOut( __METHOD__.'-strtr' );
+			wfProfileOut( __METHOD__ . '-strtr' );
 		}
 		return $result;
 	}
@@ -424,7 +511,7 @@ class ReplacementArray {
 
 /**
  * An iterator which works exactly like:
- * 
+ *
  * foreach ( explode( $delim, $s ) as $element ) {
  *    ...
  * }
@@ -449,15 +536,15 @@ class ExplodeIterator implements Iterator {
 
 	/**
 	 * Construct a DelimIterator
-	 * @param $delim string
-	 * @param $s string
+	 * @param string $delim
+	 * @param string $subject
 	 */
-	function __construct( $delim, $s ) {
-		$this->subject = $s;
+	function __construct( $delim, $subject ) {
+		$this->subject = $subject;
 		$this->delim = $delim;
 
 		// Micro-optimisation (theoretical)
-		$this->subjectLength = strlen( $s );
+		$this->subjectLength = strlen( $subject );
 		$this->delimLength = strlen( $delim );
 
 		$this->rewind();
@@ -485,6 +572,9 @@ class ExplodeIterator implements Iterator {
 		return $this->current;
 	}
 
+	/**
+	 * @return int|bool Current position or boolean false if invalid
+	 */
 	function key() {
 		return $this->curPos;
 	}