mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/AbuseFilter.git
synced 2024-09-24 10:48:17 +00:00
280 lines
6.7 KiB
PHP
280 lines
6.7 KiB
PHP
<?php
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namespace MediaWiki\Extension\AbuseFilter\Parser;
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use BagOStuff;
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use MediaWiki\Extension\AbuseFilter\Parser\Exception\UserVisibleException;
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/**
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* Tokenizer for AbuseFilter rules.
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*/
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class AbuseFilterTokenizer {
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/** @var int Tokenizer cache version. Increment this when changing the syntax. */
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public const CACHE_VERSION = 4;
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private const COMMENT_START_RE = '/\s*\/\*/A';
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private const ID_SYMBOL_RE = '/[0-9A-Za-z_]+/A';
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public const OPERATOR_RE =
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'/(\!\=\=|\!\=|\!|\*\*|\*|\/|\+|\-|%|&|\||\^|\:\=|\?|\:|\<\=|\<|\>\=|\>|\=\=\=|\=\=|\=)/A';
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private const BASE = '0(?<base>[xbo])';
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private const DIGIT = '[0-9A-Fa-f]';
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private const DIGITS = self::DIGIT . '+' . '(?:\.\d*)?|\.\d+';
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private const RADIX_RE = '/(?:' . self::BASE . ')?(?<input>' . self::DIGITS . ')(?!\w)/Au';
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private const WHITESPACE = "\011\012\013\014\015\040";
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// Order is important. The punctuation-matching regex requires that
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// ** comes before *, etc. They are sorted to make it easy to spot
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// such errors.
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public const OPERATORS = [
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// Inequality
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'!==', '!=', '!',
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// Multiplication/exponentiation
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'**', '*',
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// Other arithmetic
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'/', '+', '-', '%',
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// Logic
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'&', '|', '^',
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// Setting
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':=',
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// Ternary
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'?', ':',
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// Less than
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'<=', '<',
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// Greater than
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'>=', '>',
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// Equality
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'===', '==', '=',
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];
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public const PUNCTUATION = [
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',' => AFPToken::TCOMMA,
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'(' => AFPToken::TBRACE,
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')' => AFPToken::TBRACE,
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'[' => AFPToken::TSQUAREBRACKET,
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']' => AFPToken::TSQUAREBRACKET,
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';' => AFPToken::TSTATEMENTSEPARATOR,
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];
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public const BASES = [
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'b' => 2,
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'x' => 16,
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'o' => 8
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];
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public const BASE_CHARS_RES = [
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2 => '/^[01]+$/',
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8 => '/^[0-7]+$/',
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16 => '/^[0-9A-Fa-f]+$/',
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10 => '/^[0-9.]+$/',
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];
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public const KEYWORDS = [
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'in', 'like', 'true', 'false', 'null', 'contains', 'matches',
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'rlike', 'irlike', 'regex', 'if', 'then', 'else', 'end',
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];
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/**
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* @var BagOStuff
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*/
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private $cache;
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/**
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* @param BagOStuff $cache
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*/
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public function __construct( BagOStuff $cache ) {
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$this->cache = $cache;
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}
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/**
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* Get a cache key used to store the tokenized code
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*
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* @param string $code Not yet tokenized
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* @return string
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* @internal
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*/
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public function getCacheKey( $code ) {
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return $this->cache->makeGlobalKey( __CLASS__, self::CACHE_VERSION, crc32( $code ) );
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}
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/**
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* Get the tokens for the given code.
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*
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* @param string $code
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* @return array[]
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* @phan-return array<int,array{0:AFPToken,1:int}>
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*/
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public function getTokens( string $code ): array {
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return $this->cache->getWithSetCallback(
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$this->getCacheKey( $code ),
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BagOStuff::TTL_DAY,
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function () use ( $code ) {
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return $this->tokenize( $code );
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}
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);
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}
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/**
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* @param string $code
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* @return array[]
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* @phan-return array<int,array{0:AFPToken,1:int}>
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*/
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private function tokenize( string $code ): array {
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$tokens = [];
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$curPos = 0;
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do {
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$prevPos = $curPos;
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$token = $this->nextToken( $code, $curPos );
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$tokens[ $token->pos ] = [ $token, $curPos ];
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} while ( $curPos !== $prevPos );
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return $tokens;
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}
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/**
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* @param string $code
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* @param int &$offset
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* @return AFPToken
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* @throws UserVisibleException
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*/
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private function nextToken( $code, &$offset ) {
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$matches = [];
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$start = $offset;
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// Read past comments
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while ( preg_match( self::COMMENT_START_RE, $code, $matches, 0, $offset ) ) {
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if ( strpos( $code, '*/', $offset ) === false ) {
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throw new UserVisibleException(
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'unclosedcomment', $offset, [] );
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}
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$offset = strpos( $code, '*/', $offset ) + 2;
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}
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// Spaces
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$offset += strspn( $code, self::WHITESPACE, $offset );
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if ( $offset >= strlen( $code ) ) {
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return new AFPToken( AFPToken::TNONE, '', $start );
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}
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$chr = $code[$offset];
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// Punctuation
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if ( isset( self::PUNCTUATION[$chr] ) ) {
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$offset++;
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return new AFPToken( self::PUNCTUATION[$chr], $chr, $start );
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}
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// String literal
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if ( $chr === '"' || $chr === "'" ) {
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return self::readStringLiteral( $code, $offset, $start );
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}
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$matches = [];
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// Operators
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if ( preg_match( self::OPERATOR_RE, $code, $matches, 0, $offset ) ) {
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$token = $matches[0];
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$offset += strlen( $token );
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return new AFPToken( AFPToken::TOP, $token, $start );
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}
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// Numbers
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$matchesv2 = [];
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if ( preg_match( self::RADIX_RE, $code, $matchesv2, 0, $offset ) ) {
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$token = $matchesv2[0];
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$baseChar = $matchesv2['base'];
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$input = $matchesv2['input'];
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$base = $baseChar ? self::BASES[$baseChar] : 10;
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if ( preg_match( self::BASE_CHARS_RES[$base], $input ) ) {
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$num = $base !== 10 ? base_convert( $input, $base, 10 ) : $input;
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$offset += strlen( $token );
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return ( strpos( $input, '.' ) !== false )
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? new AFPToken( AFPToken::TFLOAT, floatval( $num ), $start )
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: new AFPToken( AFPToken::TINT, intval( $num ), $start );
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}
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}
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// IDs / Keywords
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if ( preg_match( self::ID_SYMBOL_RE, $code, $matches, 0, $offset ) ) {
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$token = $matches[0];
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$offset += strlen( $token );
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$type = in_array( $token, self::KEYWORDS )
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? AFPToken::TKEYWORD
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: AFPToken::TID;
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return new AFPToken( $type, $token, $start );
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}
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throw new UserVisibleException(
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'unrecognisedtoken', $start, [ substr( $code, $start ) ] );
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}
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/**
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* @param string $code
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* @param int &$offset
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* @param int $start
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* @return AFPToken
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* @throws UserVisibleException
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*/
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private static function readStringLiteral( $code, &$offset, $start ) {
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$type = $code[$offset];
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$offset++;
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$length = strlen( $code );
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$token = '';
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while ( $offset < $length ) {
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if ( $code[$offset] === $type ) {
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$offset++;
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return new AFPToken( AFPToken::TSTRING, $token, $start );
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}
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// Performance: Use a PHP function (implemented in C)
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// to scan ahead.
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$addLength = strcspn( $code, $type . "\\", $offset );
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if ( $addLength ) {
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$token .= substr( $code, $offset, $addLength );
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$offset += $addLength;
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} elseif ( $code[$offset] === '\\' ) {
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switch ( $code[$offset + 1] ) {
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case '\\':
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$token .= '\\';
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break;
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case $type:
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$token .= $type;
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break;
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case 'n':
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$token .= "\n";
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break;
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case 'r':
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$token .= "\r";
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break;
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case 't':
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$token .= "\t";
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break;
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case 'x':
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$chr = substr( $code, $offset + 2, 2 );
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if ( preg_match( '/^[0-9A-Fa-f]{2}$/', $chr ) ) {
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$token .= chr( hexdec( $chr ) );
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// \xXX -- 2 done later
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$offset += 2;
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} else {
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$token .= '\\x';
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}
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break;
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default:
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$token .= "\\" . $code[$offset + 1];
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}
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$offset += 2;
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} else {
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// Should never happen
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// @codeCoverageIgnoreStart
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$token .= $code[$offset];
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$offset++;
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// @codeCoverageIgnoreEnd
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}
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}
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throw new UserVisibleException( 'unclosedstring', $offset, [] );
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}
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}
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