<?php

/**
 * Abuse filter parser.
 * Copyright © Victor Vasiliev, 2008.
 * Based on ideas by Andrew Garrett
 * Distributed under GNU GPL v2 terms.
 *
 * Types of token:
 * * T_NONE - special-purpose token
 * * T_BRACE  - ( or )
 * * T_COMMA - ,
 * * T_OP - operator like + or ^
 * * T_NUMBER - number
 * * T_STRING - string, in "" or ''
 * * T_KEYWORD - keyword
 * * T_ID - identifier
 * * T_STATEMENT_SEPARATOR - ;
 * * T_SQUARE_BRACKETS - [ or ]
 *
 * Levels of parsing:
 * * Entry - catches unexpected characters
 * * Semicolon - ;
 * * Set - :=
 * * Conditionls (IF) - if-then-else-end, cond ? a :b
 * * BoolOps (BO) - &, |, ^
 * * CompOps (CO) - ==, !=, ===, !==, >, <, >=, <=
 * * SumRel (SR) - +, -
 * * MulRel (MR) - *, /, %
 * * Pow (P) - **
 * * BoolNeg (BN) - ! operation
 * * SpecialOperators (SO) - in and like
 * * Unarys (U) - plus and minus in cases like -5 or -(2 * +2)
 * * ListElement (LE) - list[number]
 * * Braces (B) - ( and )
 * * Functions (F)
 * * Atom (A) - return value
 */

class AFPToken {
	// Types of tken
	const TNONE = 'T_NONE';
	const TID = 'T_ID';
	const TKEYWORD = 'T_KEYWORD';
	const TSTRING = 'T_STRING';
	const TINT = 'T_INT';
	const TFLOAT = 'T_FLOAT';
	const TOP = 'T_OP';
	const TBRACE = 'T_BRACE';
	const TSQUAREBRACKET = 'T_SQUARE_BRACKET';
	const TCOMMA = 'T_COMMA';
	const TSTATEMENTSEPARATOR = 'T_STATEMENT_SEPARATOR';

	public $type;
	public $value;
	public $pos;

	public function __construct( $type = self::TNONE, $value = null, $pos = 0 ) {
		$this->type = $type;
		$this->value = $value;
		$this->pos = $pos;
	}
}

class AFPData {
	// Datatypes
	const DINT = 'int';
	const DSTRING = 'string';
	const DNULL = 'null';
	const DBOOL = 'bool';
	const DFLOAT = 'float';
	const DLIST = 'list';

	// Translation table mapping shell-style wildcards to PCRE equivalents.
	// Derived from <http://www.php.net/manual/en/function.fnmatch.php#100207>
	private static $wildcardMap = array(
		'\*' => '.*',
		'\+' => '\+',
		'\-' => '\-',
		'\.' => '\.',
		'\?' => '.',
		'\[' => '[',
		'\[\!' => '[^',
		'\\' => '\\\\',
		'\]' => ']',
	);

	public $type;
	public $data;

	/**
	 * @param string $type
	 * @param null $val
	 */
	public function __construct( $type = self::DNULL, $val = null ) {
		$this->type = $type;
		$this->data = $val;
	}

	/**
	 * @param $var
	 * @return AFPData
	 * @throws AFPException
	 */
	public static function newFromPHPVar( $var ) {
		if ( is_string( $var ) ) {
			return new AFPData( self::DSTRING, $var );
		} elseif ( is_int( $var ) ) {
			return new AFPData( self::DINT, $var );
		} elseif ( is_float( $var ) ) {
			return new AFPData( self::DFLOAT, $var );
		} elseif ( is_bool( $var ) ) {
			return new AFPData( self::DBOOL, $var );
		} elseif ( is_array( $var ) ) {
			$result = array();
			foreach ( $var as $item ) {
				$result[] = self::newFromPHPVar( $item );
			}

			return new AFPData( self::DLIST, $result );
		} elseif ( is_null( $var ) ) {
			return new AFPData();
		} else {
			throw new AFPException(
				'Data type ' . gettype( $var ) . ' is not supported by AbuseFilter'
			);
		}
	}

	/**
	 * @return AFPData
	 */
	public function dup() {
		return new AFPData( $this->type, $this->data );
	}

	/**
	 * @param $orig AFPData
	 * @param $target
	 * @return AFPData
	 */
	public static function castTypes( $orig, $target ) {
		if ( $orig->type == $target ) {
			return $orig->dup();
		}
		if ( $target == self::DNULL ) {
			return new AFPData();
		}

		if ( $orig->type == self::DLIST ) {
			if ( $target == self::DBOOL ) {
				return new AFPData( self::DBOOL, (bool)count( $orig->data ) );
			}
			if ( $target == self::DFLOAT ) {
				return new AFPData( self::DFLOAT, floatval( count( $orig->data ) ) );
			}
			if ( $target == self::DINT ) {
				return new AFPData( self::DINT, intval( count( $orig->data ) ) );
			}
			if ( $target == self::DSTRING ) {
				$s = '';
				foreach ( $orig->data as $item ) {
					$s .= $item->toString() . "\n";
				}

				return new AFPData( self::DSTRING, $s );
			}
		}

		if ( $target == self::DBOOL ) {
			return new AFPData( self::DBOOL, (bool)$orig->data );
		}
		if ( $target == self::DFLOAT ) {
			return new AFPData( self::DFLOAT, floatval( $orig->data ) );
		}
		if ( $target == self::DINT ) {
			return new AFPData( self::DINT, intval( $orig->data ) );
		}
		if ( $target == self::DSTRING ) {
			return new AFPData( self::DSTRING, strval( $orig->data ) );
		}
		if ( $target == self::DLIST ) {
			return new AFPData( self::DLIST, array( $orig ) );
		}
	}

	/**
	 * @param $value AFPData
	 * @return AFPData
	 */
	public static function boolInvert( $value ) {
		return new AFPData( self::DBOOL, !$value->toBool() );
	}

	/**
	 * @param $base AFPData
	 * @param $exponent AFPData
	 * @return AFPData
	 */
	public static function pow( $base, $exponent ) {
		return new AFPData( self::DFLOAT, pow( $base->toFloat(), $exponent->toFloat() ) );
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @return AFPData
	 */
	public static function keywordIn( $a, $b ) {
		$a = $a->toString();
		$b = $b->toString();

		if ( $a == '' || $b == '' ) {
			return new AFPData( self::DBOOL, false );
		}

		return new AFPData( self::DBOOL, strpos( $b, $a ) !== false );
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @return AFPData
	 */
	public static function keywordContains( $a, $b ) {
		$a = $a->toString();
		$b = $b->toString();

		if ( $a == '' || $b == '' ) {
			return new AFPData( self::DBOOL, false );
		}

		return new AFPData( self::DBOOL, strpos( $a, $b ) !== false );
	}

	/**
	 * @param $value
	 * @param $list
	 * @return bool
	 */
	public static function listContains( $value, $list ) {
		// Should use built-in PHP function somehow
		foreach ( $list->data as $item ) {
			if ( self::equals( $value, $item ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * @param $d1 AFPData
	 * @param $d2 AFPData
	 * @return bool
	 */
	public static function equals( $d1, $d2 ) {
		return $d1->type != self::DLIST && $d2->type != self::DLIST &&
		$d1->toString() === $d2->toString();
	}

	/**
	 * @param $str AFPData
	 * @param $pattern AFPData
	 * @return AFPData
	 */
	public static function keywordLike( $str, $pattern ) {
		$str = $str->toString();
		$pattern = '#^' . strtr( preg_quote( $pattern->toString(), '#' ), self::$wildcardMap ) . '$#u';
		wfSuppressWarnings();
		$result = preg_match( $pattern, $str );
		wfRestoreWarnings();

		return new AFPData( self::DBOOL, (bool)$result );
	}

	/**
	 * @param $str AFPData
	 * @param $regex AFPData
	 * @param $pos
	 * @param $insensitive bool
	 * @return AFPData
	 * @throws Exception
	 */
	public static function keywordRegex( $str, $regex, $pos, $insensitive = false ) {
		$str = $str->toString();
		$pattern = $regex->toString();

		$pattern = preg_replace( '!(\\\\\\\\)*(\\\\)?/!', '$1\/', $pattern );
		$pattern = "/$pattern/u";

		if ( $insensitive ) {
			$pattern .= 'i';
		}

		$result = preg_match( $pattern, $str );
		if ( $result === false ) {
			throw new AFPUserVisibleException(
				'regexfailure',
				$pos,
				array( 'unspecified error in preg_match()', $pattern )
			);
		}

		return new AFPData( self::DBOOL, (bool)$result );
	}

	/**
	 * @param $str
	 * @param $regex
	 * @param $pos
	 * @return AFPData
	 */
	public static function keywordRegexInsensitive( $str, $regex, $pos ) {
		return self::keywordRegex( $str, $regex, $pos, true );
	}

	/**
	 * @param $data AFPData
	 * @return AFPData
	 */
	public static function unaryMinus( $data ) {
		if ( $data->type == self::DINT ) {
			return new AFPData( $data->type, -$data->toInt() );
		} else {
			return new AFPData( $data->type, -$data->toFloat() );
		}
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @param $op string
	 * @return AFPData
	 * @throws AFPException
	 */
	public static function boolOp( $a, $b, $op ) {
		$a = $a->toBool();
		$b = $b->toBool();
		if ( $op == '|' ) {
			return new AFPData( self::DBOOL, $a || $b );
		}
		if ( $op == '&' ) {
			return new AFPData( self::DBOOL, $a && $b );
		}
		if ( $op == '^' ) {
			return new AFPData( self::DBOOL, $a xor $b );
		}
		throw new AFPException( "Invalid boolean operation: {$op}" ); // Should never happen.
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @param $op string
	 * @return AFPData
	 * @throws AFPException
	 */
	public static function compareOp( $a, $b, $op ) {
		if ( $op == '==' || $op == '=' ) {
			return new AFPData( self::DBOOL, self::equals( $a, $b ) );
		}
		if ( $op == '!=' ) {
			return new AFPData( self::DBOOL, !self::equals( $a, $b ) );
		}
		if ( $op == '===' ) {
			return new AFPData( self::DBOOL, $a->type == $b->type && self::equals( $a, $b ) );
		}
		if ( $op == '!==' ) {
			return new AFPData( self::DBOOL, $a->type != $b->type || !self::equals( $a, $b ) );
		}
		$a = $a->toString();
		$b = $b->toString();
		if ( $op == '>' ) {
			return new AFPData( self::DBOOL, $a > $b );
		}
		if ( $op == '<' ) {
			return new AFPData( self::DBOOL, $a < $b );
		}
		if ( $op == '>=' ) {
			return new AFPData( self::DBOOL, $a >= $b );
		}
		if ( $op == '<=' ) {
			return new AFPData( self::DBOOL, $a <= $b );
		}
		throw new AFPException( "Invalid comparison operation: {$op}" ); // Should never happen
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @param $op string
	 * @param $pos
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 * @throws AFPException
	 */
	public static function mulRel( $a, $b, $op, $pos ) {
		// Figure out the type.
		if ( $a->type == self::DFLOAT || $b->type == self::DFLOAT ||
			$a->toFloat() != $a->toString() || $b->toFloat() != $b->toString()
		) {
			$type = self::DFLOAT;
			$a = $a->toFloat();
			$b = $b->toFloat();
		} else {
			$type = self::DINT;
			$a = $a->toInt();
			$b = $b->toInt();
		}

		if ( $op != '*' && $b == 0 ) {
			throw new AFPUserVisibleException( 'dividebyzero', $pos, array( $a ) );
		}

		if ( $op == '*' ) {
			$data = $a * $b;
		} elseif ( $op == '/' ) {
			$data = $a / $b;
		} elseif ( $op == '%' ) {
			$data = $a % $b;
		} else {
			// Should never happen
			throw new AFPException( "Invalid multiplication-related operation: {$op}" );
		}

		if ( $type == self::DINT ) {
			$data = intval( $data );
		} else {
			$data = floatval( $data );
		}

		return new AFPData( $type, $data );
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @return AFPData
	 */
	public static function sum( $a, $b ) {
		if ( $a->type == self::DSTRING || $b->type == self::DSTRING ) {
			return new AFPData( self::DSTRING, $a->toString() . $b->toString() );
		} elseif ( $a->type == self::DLIST && $b->type == self::DLIST ) {
			return new AFPData( self::DLIST, array_merge( $a->toList(), $b->toList() ) );
		} else {
			return new AFPData( self::DFLOAT, $a->toFloat() + $b->toFloat() );
		}
	}

	/**
	 * @param $a AFPData
	 * @param $b AFPData
	 * @return AFPData
	 */
	public static function sub( $a, $b ) {
		return new AFPData( self::DFLOAT, $a->toFloat() - $b->toFloat() );
	}

	/** Convert shorteners */

	/**
	 * @throws MWException
	 * @return mixed
	 */
	public function toNative() {
		switch ( $this->type ) {
			case self::DBOOL:
				return $this->toBool();
			case self::DSTRING:
				return $this->toString();
			case self::DFLOAT:
				return $this->toFloat();
			case self::DINT:
				return $this->toInt();
			case self::DLIST:
				$input = $this->toList();
				$output = array();
				foreach ( $input as $item ) {
					$output[] = $item->toNative();
				}

				return $output;
			case self::DNULL:
				return null;
			default:
				throw new MWException( "Unknown type" );
		}
	}

	/**
	 * @return bool
	 */
	public function toBool() {
		return self::castTypes( $this, self::DBOOL )->data;
	}

	/**
	 * @return string
	 */
	public function toString() {
		return self::castTypes( $this, self::DSTRING )->data;
	}

	/**
	 * @return float
	 */
	public function toFloat() {
		return self::castTypes( $this, self::DFLOAT )->data;
	}

	/**
	 * @return int
	 */
	public function toInt() {
		return self::castTypes( $this, self::DINT )->data;
	}

	public function toList() {
		return self::castTypes( $this, self::DLIST )->data;
	}
}

class AFPParserState {
	public $pos, $token;

	public function __construct( $token, $pos ) {
		$this->token = $token;
		$this->pos = $pos;
	}
}

class AFPException extends MWException {
}

// Exceptions that we might conceivably want to report to ordinary users
// (i.e. exceptions that don't represent bugs in the extension itself)
class AFPUserVisibleException extends AFPException {
	public $mExceptionId;
	public $mPosition;
	public $mParams;

	/**
	 * @param string $exception_id
	 * @param int $position
	 * @param array $params
	 */
	function __construct( $exception_id, $position, $params ) {
		$this->mExceptionID = $exception_id;
		$this->mPosition = $position;
		$this->mParams = $params;

		// Exception message text for logs should be in English.
		$msg = $this->getMessageObj()->inLanguage( 'en' )->useDatabase( false )->text();
		parent::__construct( $msg );
	}

	public function getMessageObj() {
		// Give grep a chance to find the usages:
		// abusefilter-exception-unexpectedatend, abusefilter-exception-expectednotfound
		// abusefilter-exception-unrecognisedkeyword, abusefilter-exception-unexpectedtoken
		// abusefilter-exception-unclosedstring, abusefilter-exception-invalidoperator
		// abusefilter-exception-unrecognisedtoken, abusefilter-exception-noparams
		// abusefilter-exception-dividebyzero, abusefilter-exception-unrecognisedvar
		// abusefilter-exception-notenoughargs, abusefilter-exception-regexfailure
		// abusefilter-exception-overridebuiltin, abusefilter-exception-outofbounds
		// abusefilter-exception-notlist
		return wfMessage(
			'abusefilter-exception-' . $this->mExceptionID,
			array_merge( array( $this->mPosition ), $this->mParams )
		);
	}
}

class AbuseFilterParser {
	public $mCode, $mTokens, $mPos, $mCur, $mShortCircuit, $mAllowShort, $mLen;

	/**
	 * @var AbuseFilterVariableHolder
	 */
	public $mVars;

	// length,lcase,ucase,ccnorm,rmdoubles,specialratio,rmspecials,norm,count
	public static $mFunctions = array(
		'lcase' => 'funcLc',
		'ucase' => 'funcUc',
		'length' => 'funcLen',
		'string' => 'castString',
		'int' => 'castInt',
		'float' => 'castFloat',
		'bool' => 'castBool',
		'norm' => 'funcNorm',
		'ccnorm' => 'funcCCNorm',
		'specialratio' => 'funcSpecialRatio',
		'rmspecials' => 'funcRMSpecials',
		'rmdoubles' => 'funcRMDoubles',
		'rmwhitespace' => 'funcRMWhitespace',
		'count' => 'funcCount',
		'rcount' => 'funcRCount',
		'ip_in_range' => 'funcIPInRange',
		'contains_any' => 'funcContainsAny',
		'substr' => 'funcSubstr',
		'strlen' => 'funcLen',
		'strpos' => 'funcStrPos',
		'str_replace' => 'funcStrReplace',
		'rescape' => 'funcStrRegexEscape',
		'set' => 'funcSetVar',
		'set_var' => 'funcSetVar',
	);

	// Functions that affect parser state, and shouldn't be cached.
	public static $ActiveFunctions = array(
		'funcSetVar',
	);

	public static $funcCache = array();

	private static $hasSmartPregMatchAll = null;

	/**
	 * Create a new instance
	 *
	 * @param $vars AbuseFilterVariableHolder
	 */
	public function __construct( $vars = null ) {
		$this->resetState();
		if ( $vars instanceof AbuseFilterVariableHolder ) {
			$this->mVars = $vars;
		}
		if ( self::$hasSmartPregMatchAll === null ) {
			// Starting with PHP 5.4, preg_match_all() allows omitting the '$matches' argument.
			$r = new ReflectionFunction( 'preg_match_all' );
			self::$hasSmartPregMatchAll = $r->getNumberOfRequiredParameters() === 2;
		}
	}

	public function resetState() {
		$this->mCode = '';
		$this->mTokens = array();
		$this->mVars = new AbuseFilterVariableHolder;
		$this->mPos = 0;
		$this->mShortCircuit = false;
		$this->mAllowShort = true;
	}

	/**
	 * @param $filter
	 * @return array|bool
	 */
	public function checkSyntax( $filter ) {
		try {
			$origAS = $this->mAllowShort;
			$this->mAllowShort = false;
			$this->parse( $filter );
		} catch ( AFPUserVisibleException $excep ) {
			$this->mAllowShort = $origAS;

			return array( $excep->getMessageObj()->text(), $excep->mPosition );
		}
		$this->mAllowShort = $origAS;

		return true;
	}

	/**
	 * @param $name
	 * @param $value
	 */
	public function setVar( $name, $value ) {
		$this->mVars->setVar( $name, $value );
	}

	/**
	 * @param $vars
	 */
	public function setVars( $vars ) {
		if ( is_array( $vars ) ) {
			foreach ( $vars as $name => $var ) {
				$this->setVar( $name, $var );
			}
		} elseif ( $vars instanceof AbuseFilterVariableHolder ) {
			$this->mVars->addHolders( $vars );
		}
	}

	/**
	 * @return AFPToken
	 */
	protected function move() {
		list( $this->mCur, $this->mPos ) = $this->mTokens[$this->mPos];
	}

	/**
	 * getState() function allows parser state to be rollbacked to several tokens back
	 * @return AFPParserState
	 */
	protected function getState() {
		return new AFPParserState( $this->mCur, $this->mPos );
	}

	/**
	 * setState() function allows parser state to be rollbacked to several tokens back
	 * @param AFPParserState $state
	 */
	protected function setState( AFPParserState $state ) {
		$this->mCur = $state->token;
		$this->mPos = $state->pos;
	}

	/**
	 * @return mixed
	 * @throws AFPUserVisibleException
	 */
	protected function skipOverBraces() {
		if ( !( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == '(' ) ||
			!$this->mShortCircuit
		) {
			return;
		}

		$braces = 1;
		while ( $this->mCur->type != AFPToken::TNONE && $braces > 0 ) {
			$this->move();
			if ( $this->mCur->type == AFPToken::TBRACE ) {
				if ( $this->mCur->value == '(' ) {
					$braces++;
				} elseif ( $this->mCur->value == ')' ) {
					$braces--;
				}
			}
		}
		if ( !( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == ')' ) )
			throw new AFPUserVisibleException( 'expectednotfound', $this->mCur->pos, array( ')' ) );
	}

	/**
	 * @param $code
	 * @return bool
	 */
	public function parse( $code ) {
		return $this->intEval( $code )->toBool();
	}

	/**
	 * @param $filter
	 * @return string
	 */
	public function evaluateExpression( $filter ) {
		return $this->intEval( $filter )->toString();
	}

	/**
	 * @param $code
	 * @return AFPData
	 */
	function intEval( $code ) {
		// Setup, resetting
		$this->mCode = $code;
		$this->mTokens = AbuseFilterTokenizer::tokenize( $code );
		$this->mPos = 0;
		$this->mLen = strlen( $code );
		$this->mShortCircuit = false;

		$result = new AFPData();
		$this->doLevelEntry( $result );

		return $result;
	}

	/**
	 * @param $a
	 * @param $b
	 * @return int
	 */
	static function lengthCompare( $a, $b ) {
		if ( strlen( $a ) == strlen( $b ) ) {
			return 0;
		}

		return ( strlen( $a ) < strlen( $b ) ) ? -1 : 1;
	}

	/* Levels */

	/**
	 * Handles unexpected characters after the expression
	 *
	 * @param $result AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelEntry( &$result ) {
		$this->doLevelSemicolon( $result );

		if ( $this->mCur->type != AFPToken::TNONE ) {
			throw new AFPUserVisibleException(
				'unexpectedatend',
				$this->mCur->pos, array( $this->mCur->type )
			);
		}
	}

	/**
	 * Handles multiple expressions
	 * @param $result AFPData
	 */
	protected function doLevelSemicolon( &$result ) {
		do {
			$this->move();
			if ( $this->mCur->type != AFPToken::TSTATEMENTSEPARATOR ) {
				$this->doLevelSet( $result );
			}
		} while ( $this->mCur->type == AFPToken::TSTATEMENTSEPARATOR );
	}

	/**
	 * Handles multiple expressions
	 *
	 * @param $result AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelSet( &$result ) {
		if ( $this->mCur->type == AFPToken::TID ) {
			$varname = $this->mCur->value;
			$prev = $this->getState();
			$this->move();

			if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':=' ) {
				$this->move();
				$this->doLevelSet( $result );
				$this->setUserVariable( $varname, $result );

				return;
			} elseif ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == '[' ) {
				if ( !$this->mVars->varIsSet( $varname ) ) {
					throw new AFPUserVisibleException( 'unrecognisedvar',
						$this->mCur->pos,
						array( $varname )
					);
				}
				$list = $this->mVars->getVar( $varname );
				if ( $list->type != AFPData::DLIST ) {
					throw new AFPUserVisibleException( 'notlist', $this->mCur->pos, array() );
				}
				$list = $list->toList();
				$this->move();
				if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
					$idx = 'new';
				} else {
					$this->setState( $prev );
					$this->move();
					$idx = new AFPData();
					$this->doLevelSemicolon( $idx );
					$idx = $idx->toInt();
					if ( !( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) ) {
						throw new AFPUserVisibleException( 'expectednotfound', $this->mCur->pos,
							array( ']', $this->mCur->type, $this->mCur->value ) );
					}
					if ( count( $list ) <= $idx ) {
						throw new AFPUserVisibleException( 'outofbounds', $this->mCur->pos,
							array( $idx, count( $result->data ) ) );
					}
				}
				$this->move();
				if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':=' ) {
					$this->move();
					$this->doLevelSet( $result );
					if ( $idx === 'new' ) {
						$list[] = $result;
					} else {
						$list[$idx] = $result;
					}
					$this->setUserVariable( $varname, new AFPData( AFPData::DLIST, $list ) );

					return;
				} else {
					$this->setState( $prev );
				}
			} else {
				$this->setState( $prev );
			}
		}
		$this->doLevelConditions( $result );
	}

	/**
	 * @param $result AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelConditions( &$result ) {
		if ( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'if' ) {
			$this->move();
			$this->doLevelBoolOps( $result );

			if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'then' ) )
				throw new AFPUserVisibleException( 'expectednotfound',
					$this->mCur->pos,
					array(
						'then',
						$this->mCur->type,
						$this->mCur->value
					)
				);
			$this->move();

			$r1 = new AFPData();
			$r2 = new AFPData();

			$isTrue = $result->toBool();

			if ( !$isTrue ) {
				$scOrig = $this->mShortCircuit;
				$this->mShortCircuit = $this->mAllowShort;
			}
			$this->doLevelConditions( $r1 );
			if ( !$isTrue ) {
				$this->mShortCircuit = $scOrig;
			}

			if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'else' ) )
				throw new AFPUserVisibleException( 'expectednotfound',
					$this->mCur->pos,
					array(
						'else',
						$this->mCur->type,
						$this->mCur->value
					)
				);
			$this->move();

			if ( $isTrue ) {
				$scOrig = $this->mShortCircuit;
				$this->mShortCircuit = $this->mAllowShort;
			}
			$this->doLevelConditions( $r2 );
			if ( $isTrue ) {
				$this->mShortCircuit = $scOrig;
			}

			if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'end' ) )
				throw new AFPUserVisibleException( 'expectednotfound',
					$this->mCur->pos,
					array(
						'end',
						$this->mCur->type,
						$this->mCur->value
					)
				);
			$this->move();

			if ( $result->toBool() ) {
				$result = $r1;
			} else {
				$result = $r2;
			}
		} else {
			$this->doLevelBoolOps( $result );
			if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '?' ) {
				$this->move();
				$r1 = new AFPData();
				$r2 = new AFPData();

				$isTrue = $result->toBool();

				if ( !$isTrue ) {
					$scOrig = $this->mShortCircuit;
					$this->mShortCircuit = $this->mAllowShort;
				}
				$this->doLevelConditions( $r1 );
				if ( !$isTrue ) {
					$this->mShortCircuit = $scOrig;
				}

				if ( !( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':' ) )
					throw new AFPUserVisibleException( 'expectednotfound',
						$this->mCur->pos,
						array(
							':',
							$this->mCur->type,
							$this->mCur->value
						)
					);
				$this->move();

				if ( $isTrue ) {
					$scOrig = $this->mShortCircuit;
					$this->mShortCircuit = $this->mAllowShort;
				}
				$this->doLevelConditions( $r2 );
				if ( $isTrue ) {
					$this->mShortCircuit = $scOrig;
				}

				if ( $isTrue ) {
					$result = $r1;
				} else {
					$result = $r2;
				}
			}
		}
	}

	/**
	 * @param $result AFPData
	 */
	protected function doLevelBoolOps( &$result ) {
		$this->doLevelCompares( $result );
		$ops = array( '&', '|', '^' );
		while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
			$op = $this->mCur->value;
			$this->move();
			$r2 = new AFPData();

			// We can go on quickly as either one statement with | is true or on with & is false
			if ( ( $op == '&' && !$result->toBool() ) || ( $op == '|' && $result->toBool() ) ) {
				wfProfileIn( __METHOD__ . '-shortcircuit' );
				$orig = $this->mShortCircuit;
				$this->mShortCircuit = $this->mAllowShort;
				$this->doLevelCompares( $r2 );
				$this->mShortCircuit = $orig;
				$result = new AFPData( AFPData::DBOOL, $result->toBool() );
				wfProfileOut( __METHOD__ . '-shortcircuit' );
				continue;
			}

			$this->doLevelCompares( $r2 );

			$result = AFPData::boolOp( $result, $r2, $op );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelCompares( &$result ) {
		$this->doLevelSumRels( $result );
		$ops = array( '==', '===', '!=', '!==', '<', '>', '<=', '>=', '=' );
		while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
			$op = $this->mCur->value;
			$this->move();
			$r2 = new AFPData();
			$this->doLevelSumRels( $r2 );
			if ( $this->mShortCircuit ) {
				break; // The result doesn't matter.
			}
			AbuseFilter::triggerLimiter();
			$result = AFPData::compareOp( $result, $r2, $op );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelSumRels( &$result ) {
		$this->doLevelMulRels( $result );
		$ops = array( '+', '-' );
		while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
			$op = $this->mCur->value;
			$this->move();
			$r2 = new AFPData();
			$this->doLevelMulRels( $r2 );
			if ( $this->mShortCircuit ) {
				break; // The result doesn't matter.
			}
			if ( $op == '+' ) {
				$result = AFPData::sum( $result, $r2 );
			}
			if ( $op == '-' ) {
				$result = AFPData::sub( $result, $r2 );
			}
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelMulRels( &$result ) {
		$this->doLevelPow( $result );
		$ops = array( '*', '/', '%' );
		while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
			$op = $this->mCur->value;
			$this->move();
			$r2 = new AFPData();
			$this->doLevelPow( $r2 );
			if ( $this->mShortCircuit ) {
				break; // The result doesn't matter.
			}
			$result = AFPData::mulRel( $result, $r2, $op, $this->mCur->pos );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelPow( &$result ) {
		$this->doLevelBoolInvert( $result );
		while ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '**' ) {
			$this->move();
			$expanent = new AFPData();
			$this->doLevelBoolInvert( $expanent );
			if ( $this->mShortCircuit ) {
				break; // The result doesn't matter.
			}
			$result = AFPData::pow( $result, $expanent );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelBoolInvert( &$result ) {
		if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '!' ) {
			$this->move();
			$this->doLevelSpecialWords( $result );
			if ( $this->mShortCircuit ) {
				return; // The result doesn't matter.
			}
			$result = AFPData::boolInvert( $result );
		} else {
			$this->doLevelSpecialWords( $result );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelSpecialWords( &$result ) {
		$this->doLevelUnarys( $result );
		$keyword = strtolower( $this->mCur->value );
		$specwords = array(
			'in' => 'keywordIn',
			'like' => 'keywordLike',
			'matches' => 'keywordLike',
			'contains' => 'keywordContains',
			'rlike' => 'keywordRegex',
			'irlike' => 'keywordRegexInsensitive',
			'regex' => 'keywordRegex'
		);
		if ( $this->mCur->type == AFPToken::TKEYWORD && in_array( $keyword, array_keys( $specwords ) ) ) {
			$func = $specwords[$keyword];
			$this->move();
			$r2 = new AFPData();
			$this->doLevelUnarys( $r2 );

			if ( $this->mShortCircuit ) {
				return; // The result doesn't matter.
			}

			AbuseFilter::triggerLimiter();
			wfProfileIn( __METHOD__ . "-$func" );
			$result = AFPData::$func( $result, $r2, $this->mCur->pos );
			wfProfileOut( __METHOD__ . "-$func" );
		}
	}

	/**
	 * @param $result
	 */
	protected function doLevelUnarys( &$result ) {
		$op = $this->mCur->value;
		if ( $this->mCur->type == AFPToken::TOP && ( $op == "+" || $op == "-" ) ) {
			$this->move();
			$this->doLevelListElements( $result );
			if ( $this->mShortCircuit ) {
				return; // The result doesn't matter.
			}
			if ( $op == '-' ) {
				$result = AFPData::unaryMinus( $result );
			}
		} else {
			$this->doLevelListElements( $result );
		}
	}

	/**
	 * @param $result
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelListElements( &$result ) {
		$this->doLevelBraces( $result );
		while ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == '[' ) {
			$idx = new AFPData();
			$this->doLevelSemicolon( $idx );
			if ( !( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) ) {
				throw new AFPUserVisibleException( 'expectednotfound', $this->mCur->pos,
					array( ']', $this->mCur->type, $this->mCur->value ) );
			}
			$idx = $idx->toInt();
			if ( $result->type == AFPData::DLIST ) {
				if ( count( $result->data ) <= $idx ) {
					throw new AFPUserVisibleException( 'outofbounds', $this->mCur->pos,
						array( $idx, count( $result->data ) ) );
				}
				$result = $result->data[$idx];
			} else {
				throw new AFPUserVisibleException( 'notlist', $this->mCur->pos, array() );
			}
			$this->move();
		}
	}

	/**
	 * @param $result
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelBraces( &$result ) {
		if ( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == '(' ) {
			if ( $this->mShortCircuit ) {
				$this->skipOverBraces();
			} else {
				$this->doLevelSemicolon( $result );
			}
			if ( !( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == ')' ) )
				throw new AFPUserVisibleException(
					'expectednotfound',
					$this->mCur->pos,
					array( ')', $this->mCur->type, $this->mCur->value )
				);
			$this->move();
		} else {
			$this->doLevelFunction( $result );
		}
	}

	/**
	 * @param $result
	 * @throws AFPUserVisibleException
	 */
	protected function doLevelFunction( &$result ) {
		if ( $this->mCur->type == AFPToken::TID && isset( self::$mFunctions[$this->mCur->value] ) ) {
			$func = self::$mFunctions[$this->mCur->value];
			$this->move();
			if ( $this->mCur->type != AFPToken::TBRACE || $this->mCur->value != '(' ) {
				throw new AFPUserVisibleException( 'expectednotfound',
					$this->mCur->pos,
					array(
						'(',
						$this->mCur->type,
						$this->mCur->value
					)
				);
			}

			if ( $this->mShortCircuit ) {
				$this->skipOverBraces();
				$this->move();

				return; // The result doesn't matter.
			}

			wfProfileIn( __METHOD__ . '-loadargs' );
			$args = array();
			do {
				$r = new AFPData();
				$this->doLevelSemicolon( $r );
				$args[] = $r;
			} while ( $this->mCur->type == AFPToken::TCOMMA );

			if ( $this->mCur->type != AFPToken::TBRACE || $this->mCur->value != ')' ) {
				throw new AFPUserVisibleException( 'expectednotfound',
					$this->mCur->pos,
					array(
						')',
						$this->mCur->type,
						$this->mCur->value
					)
				);
			}
			$this->move();

			wfProfileOut( __METHOD__ . '-loadargs' );

			wfProfileIn( __METHOD__ . "-$func" );

			$funcHash = md5( $func . serialize( $args ) );

			if ( isset( self::$funcCache[$funcHash] ) &&
				!in_array( $func, self::$ActiveFunctions )
			) {
				$result = self::$funcCache[$funcHash];
			} else {
				AbuseFilter::triggerLimiter();
				$result = self::$funcCache[$funcHash] = $this->$func( $args );
			}

			if ( count( self::$funcCache ) > 1000 ) {
				self::$funcCache = array();
			}

			wfProfileOut( __METHOD__ . "-$func" );
		} else {
			$this->doLevelAtom( $result );
		}
	}

	/**
	 * @param $result
	 * @throws AFPUserVisibleException
	 * @return AFPData
	 */
	protected function doLevelAtom( &$result ) {
		$tok = $this->mCur->value;
		switch ( $this->mCur->type ) {
			case AFPToken::TID:
				if ( $this->mShortCircuit ) {
					break;
				}
				$var = strtolower( $tok );
				$result = $this->getVarValue( $var );
				break;
			case AFPToken::TSTRING:
				$result = new AFPData( AFPData::DSTRING, $tok );
				break;
			case AFPToken::TFLOAT:
				$result = new AFPData( AFPData::DFLOAT, $tok );
				break;
			case AFPToken::TINT:
				$result = new AFPData( AFPData::DINT, $tok );
				break;
			case AFPToken::TKEYWORD:
				if ( $tok == "true" ) {
					$result = new AFPData( AFPData::DBOOL, true );
				} elseif ( $tok == "false" ) {
					$result = new AFPData( AFPData::DBOOL, false );
				} elseif ( $tok == "null" ) {
					$result = new AFPData();
				} else {
					throw new AFPUserVisibleException(
						'unrecognisedkeyword',
						$this->mCur->pos,
						array( $tok )
					);
				}
				break;
			case AFPToken::TNONE:
				return; // Handled at entry level
			case AFPToken::TBRACE:
				if ( $this->mCur->value == ')' ) {
					return; // Handled at the entry level
				}
			case AFPToken::TSQUAREBRACKET:
				if ( $this->mCur->value == '[' ) {
					$list = array();
					while ( true ) {
						$this->move();
						if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
							break;
						}
						$item = new AFPData();
						$this->doLevelSet( $item );
						$list[] = $item;
						if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
							break;
						}
						if ( $this->mCur->type != AFPToken::TCOMMA ) {
							throw new AFPUserVisibleException(
								'expectednotfound',
								$this->mCur->pos,
								array( ', or ]', $this->mCur->type, $this->mCur->value )
							);
						}
					}
					$result = new AFPData( AFPData::DLIST, $list );
					break;
				}
			default:
				throw new AFPUserVisibleException(
					'unexpectedtoken',
					$this->mCur->pos,
					array(
						$this->mCur->type,
						$this->mCur->value
					)
				);
		}
		$this->move();
	}

	/* End of levels */

	/**
	 * @param $var
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function getVarValue( $var ) {
		$var = strtolower( $var );
		$builderValues = AbuseFilter::getBuilderValues();
		if ( !( array_key_exists( $var, $builderValues['vars'] )
			|| $this->mVars->varIsSet( $var ) )
		) {
			// If the variable is invalid, throw an exception
			throw new AFPUserVisibleException(
				'unrecognisedvar',
				$this->mCur->pos,
				array( $var )
			);
		} else {
			return $this->mVars->getVar( $var );
		}
	}

	/**
	 * @param $name
	 * @param $value
	 * @throws AFPUserVisibleException
	 */
	protected function setUserVariable( $name, $value ) {
		$builderValues = AbuseFilter::getBuilderValues();
		if ( array_key_exists( $name, $builderValues['vars'] ) ) {
			throw new AFPUserVisibleException( 'overridebuiltin', $this->mCur->pos, array( $name ) );
		}
		$this->mVars->setVar( $name, $value );
	}


	// Built-in functions

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcLc( $args ) {
		global $wgContLang;
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'lc', 2, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		return new AFPData( AFPData::DSTRING, $wgContLang->lc( $s ) );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcUc( $args ) {
		global $wgContLang;
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'uc', 2, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		return new AFPData( AFPData::DSTRING, $wgContLang->uc( $s ) );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcLen( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'len', 2, count( $args ) )
			);
		}
		if ( $args[0]->type == AFPData::DLIST ) {
			// Don't use toString on lists, but count
			return new AFPData( AFPData::DINT, count( $args[0]->data ) );
		}
		$s = $args[0]->toString();

		return new AFPData( AFPData::DINT, mb_strlen( $s, 'utf-8' ) );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcSimpleNorm( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'simplenorm', 2, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = preg_replace( '/[\d\W]+/', '', $s );
		$s = strtolower( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcSpecialRatio( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'specialratio', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		if ( !strlen( $s ) ) {
			return new AFPData( AFPData::DFLOAT, 0 );
		}

		$nospecials = $this->rmspecials( $s );

		$val = 1. - ( ( mb_strlen( $nospecials ) / mb_strlen( $s ) ) );

		return new AFPData( AFPData::DFLOAT, $val );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcCount( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'count', 1, count( $args ) )
			);
		}

		if ( $args[0]->type == AFPData::DLIST && count( $args ) == 1 ) {
			return new AFPData( AFPData::DINT, count( $args[0]->data ) );
		}

		if ( count( $args ) == 1 ) {
			$count = count( explode( ',', $args[0]->toString() ) );
		} else {
			$needle = $args[0]->toString();
			$haystack = $args[1]->toString();

			// Bug #60203: Keep empty parameters from causing PHP warnings
			if ( $needle === '' ) {
				$count = 0;
			} else {
				$count = substr_count( $haystack, $needle );
			}
		}

		return new AFPData( AFPData::DINT, $count );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 * @throws Exception
	 */
	protected function funcRCount( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'rcount', 1, count( $args ) )
			);
		}

		if ( count( $args ) == 1 ) {
			$count = count( explode( ',', $args[0]->toString() ) );
		} else {
			$needle = $args[0]->toString();
			$haystack = $args[1]->toString();

			# Munge the regex
			$needle = preg_replace( '!(\\\\\\\\)*(\\\\)?/!', '$1\/', $needle );
			$needle = "/$needle/u";

			if ( self::$hasSmartPregMatchAll ) {
				// Omit the '$matches' argument to avoid computing them, just count.
				$count = preg_match_all( $needle, $haystack );
			} else {
				$matches = array();
				$count = preg_match_all( $needle, $haystack, $matches );
			}

			if ( $count === false ) {
				throw new AFPUserVisibleException(
					'regexfailure',
					$this->mCur->pos,
					array( 'unspecified error in preg_match_all()', $needle )
				);
			}
		}

		return new AFPData( AFPData::DINT, $count );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcIPInRange( $args ) {
		if ( count( $args ) < 2 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'ip_in_range', 2, count( $args ) )
			);
		}

		$ip = $args[0]->toString();
		$range = $args[1]->toString();

		$result = IP::isInRange( $ip, $range );

		return new AFPData( AFPData::DBOOL, $result );
	}

	/**
	 * @param $args
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcCCNorm( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'ccnorm', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = html_entity_decode( $s, ENT_QUOTES, 'UTF-8' );
		$s = $this->ccnorm( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcContainsAny( $args ) {
		if ( count( $args ) < 2 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'contains_any', 2, count( $args ) )
			);
		}

		$s = array_shift( $args );
		$s = $s->toString();

		$searchStrings = array();

		foreach ( $args as $arg ) {
			$searchStrings[] = $arg->toString();
		}

		if ( function_exists( 'fss_prep_search' ) ) {
			$fss = fss_prep_search( $searchStrings );
			$result = fss_exec_search( $fss, $s );

			$ok = is_array( $result );
		} else {
			$ok = false;
			foreach ( $searchStrings as $needle ) {
				// Bug #60203: Keep empty parameters from causing PHP warnings
				if ( $needle !== '' && strpos( $s, $needle ) !== false ) {
					$ok = true;
					break;
				}
			}
		}

		return new AFPData( AFPData::DBOOL, $ok );
	}

	/**
	 * @param $s
	 * @return mixed
	 */
	protected function ccnorm( $s ) {
		static $replacementArray = null;

		if ( is_null( $replacementArray ) ) {
			global $wgExtensionDirectory;

			if ( is_readable( "$wgExtensionDirectory/AntiSpoof/equivset.php" ) ) {
				// Satisfy analyzer.
				$equivset = null;
				// Contains a map of characters in $equivset.
				require "$wgExtensionDirectory/AntiSpoof/equivset.php";

				// strtr in ReplacementArray->replace() doesn't like this.
				if ( isset( $equivset[''] ) ) {
					unset( $equivset[''] );
				}

				$replacementArray = new ReplacementArray( $equivset );
			} else {
				// AntiSpoof isn't available, so just create a dummy
				wfDebugLog(
					'AbuseFilter',
					"Can't compute normalized string (ccnorm) as the AntiSpoof Extension isn't installed."
				);
				$replacementArray = new ReplacementArray( array() );
			}
		}

		return $replacementArray->replace( $s );
	}

	/**
	 * @param $s string
	 * @return array|string
	 */
	protected function rmspecials( $s ) {
		return preg_replace( '/[^\p{L}\p{N}]/u', '', $s );
	}

	/**
	 * @param $s string
	 * @return array|string
	 */
	protected function rmdoubles( $s ) {
		return preg_replace( '/(.)\1+/us', '\1', $s );
	}

	/**
	 * @param $s string
	 * @return array|string
	 */
	protected function rmwhitespace( $s ) {
		return preg_replace( '/\s+/u', '', $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcRMSpecials( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'rmspecials', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = $this->rmspecials( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcRMWhitespace( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'rmwhitespace', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = $this->rmwhitespace( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcRMDoubles( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'rmdoubles', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = $this->rmdoubles( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcNorm( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'norm', 1, count( $args ) )
			);
		}
		$s = $args[0]->toString();

		$s = $this->ccnorm( $s );
		$s = $this->rmdoubles( $s );
		$s = $this->rmspecials( $s );
		$s = $this->rmwhitespace( $s );

		return new AFPData( AFPData::DSTRING, $s );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcSubstr( $args ) {
		if ( count( $args ) < 2 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'substr', 2, count( $args ) )
			);
		}

		$s = $args[0]->toString();
		$offset = $args[1]->toInt();

		if ( isset( $args[2] ) ) {
			$length = $args[2]->toInt();

			$result = mb_substr( $s, $offset, $length );
		} else {
			$result = mb_substr( $s, $offset );
		}

		return new AFPData( AFPData::DSTRING, $result );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcStrPos( $args ) {
		if ( count( $args ) < 2 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'strpos', 2, count( $args ) )
			);
		}

		$haystack = $args[0]->toString();
		$needle = $args[1]->toString();

		// Bug #60203: Keep empty parameters from causing PHP warnings
		if ( $needle === '' ) {
			return new AFPData( AFPData::DINT, -1 );
		}

		if ( isset( $args[2] ) ) {
			$offset = $args[2]->toInt();

			$result = mb_strpos( $haystack, $needle, $offset );
		} else {
			$result = mb_strpos( $haystack, $needle );
		}

		if ( $result === false )
			$result = -1;

		return new AFPData( AFPData::DINT, $result );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcStrReplace( $args ) {
		if ( count( $args ) < 3 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'str_replace', 3, count( $args ) )
			);
		}

		$subject = $args[0]->toString();
		$search = $args[1]->toString();
		$replace = $args[2]->toString();

		return new AFPData( AFPData::DSTRING, str_replace( $search, $replace, $subject ) );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function funcStrRegexEscape( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException( 'notenoughargs', $this->mCur->pos,
				array( 'rescape', 1, count( $args ) ) );
		}

		$string = $args[0]->toString();

		// preg_quote does not need the second parameter, since rlike takes
		// care of the delimiter symbol itself
		return new AFPData( AFPData::DSTRING, preg_quote( $string ) );
	}

	/**
	 * @param $args array
	 * @return mixed
	 * @throws AFPUserVisibleException
	 */
	protected function funcSetVar( $args ) {
		if ( count( $args ) < 2 ) {
			throw new AFPUserVisibleException(
				'notenoughargs',
				$this->mCur->pos,
				array( 'set_var', 2, count( $args ) )
			);
		}

		$varName = $args[0]->toString();
		$value = $args[1];

		$this->setUserVariable( $varName, $value );

		return $value;
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function castString( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException( 'noparams', $this->mCur->pos, array( __METHOD__ ) );
		}
		$val = $args[0];

		return AFPData::castTypes( $val, AFPData::DSTRING );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function castInt( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException( 'noparams', $this->mCur->pos, array( __METHOD__ ) );
		}
		$val = $args[0];

		return AFPData::castTypes( $val, AFPData::DINT );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function castFloat( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException( 'noparams', $this->mCur->pos, array( __METHOD__ ) );
		}
		$val = $args[0];

		return AFPData::castTypes( $val, AFPData::DFLOAT );
	}

	/**
	 * @param $args array
	 * @return AFPData
	 * @throws AFPUserVisibleException
	 */
	protected function castBool( $args ) {
		if ( count( $args ) < 1 ) {
			throw new AFPUserVisibleException( 'noparams', $this->mCur->pos, array( __METHOD__ ) );
		}
		$val = $args[0];

		return AFPData::castTypes( $val, AFPData::DBOOL );
	}
}