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-<?php
-/**
- * Methods to play with strings.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- * http://www.gnu.org/copyleft/gpl.html
- *
- * @file
- */
-
-/**
- * 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 bool $disableMbstring Whether to use the pure PHP
- * implementation instead of trying mb_check_encoding. Intended for unit
- * testing. Default: false
- *
- * @return bool 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, $value ) !== 0 ) {
- return false;
- }
- }
-
- return true;
- }
-
- /**
- * Perform an operation equivalent to
- *
- * preg_replace( "!$startDelim(.*?)$endDelim!", $replace, $subject );
- *
- * except that it's worst-case O(N) instead of O(N^2)
- *
- * Compared to delimiterReplace(), this implementation is fast but memory-
- * hungry and inflexible. The memory requirements are such that I don't
- * recommend using it on anything but guaranteed small chunks of text.
- *
- * @param string $startDelim
- * @param string $endDelim
- * @param string $replace
- * @param string $subject
- *
- * @return string
- */
- static function hungryDelimiterReplace( $startDelim, $endDelim, $replace, $subject ) {
- $segments = explode( $startDelim, $subject );
- $output = array_shift( $segments );
- foreach ( $segments as $s ) {
- $endDelimPos = strpos( $s, $endDelim );
- if ( $endDelimPos === false ) {
- $output .= $startDelim . $s;
- } else {
- $output .= $replace . substr( $s, $endDelimPos + strlen( $endDelim ) );
- }
- }
-
- return $output;
- }
-
- /**
- * Perform an operation equivalent to
- *
- * preg_replace_callback( "!$startDelim(.*)$endDelim!s$flags", $callback, $subject )
- *
- * This implementation is slower than hungryDelimiterReplace but uses far less
- * 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 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 string $startDelim Start delimiter
- * @param string $endDelim End delimiter
- * @param callable $callback Function to call on each match
- * @param string $subject
- * @param string $flags Regular expression flags
- * @throws MWException
- * @return string
- */
- static function delimiterReplaceCallback( $startDelim, $endDelim, $callback,
- $subject, $flags = ''
- ) {
- $inputPos = 0;
- $outputPos = 0;
- $output = '';
- $foundStart = false;
- $encStart = preg_quote( $startDelim, '!' );
- $encEnd = preg_quote( $endDelim, '!' );
- $strcmp = strpos( $flags, 'i' ) === false ? 'strcmp' : 'strcasecmp';
- $endLength = strlen( $endDelim );
- $m = array();
-
- while ( $inputPos < strlen( $subject ) &&
- preg_match( "!($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
- ) {
- # An end match is present at the same location
- $tokenType = 'end';
- $tokenLength = $endLength;
- } else {
- $tokenType = 'start';
- $tokenLength = strlen( $m[0][0] );
- }
- } elseif ( $m[2][0] != '' ) {
- $tokenType = 'end';
- $tokenLength = strlen( $m[0][0] );
- } else {
- throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
- }
-
- if ( $tokenType == 'start' ) {
- # Only move the start position if we haven't already found a start
- # This means that START START END matches outer pair
- if ( !$foundStart ) {
- # Found start
- $inputPos = $tokenOffset + $tokenLength;
- # Write out the non-matching section
- $output .= substr( $subject, $outputPos, $tokenOffset - $outputPos );
- $outputPos = $tokenOffset;
- $contentPos = $inputPos;
- $foundStart = true;
- } else {
- # Move the input position past the *first character* of START,
- # to protect against missing END when it overlaps with START
- $inputPos = $tokenOffset + 1;
- }
- } elseif ( $tokenType == 'end' ) {
- if ( $foundStart ) {
- # Found match
- $output .= call_user_func( $callback, array(
- substr( $subject, $outputPos, $tokenOffset + $tokenLength - $outputPos ),
- substr( $subject, $contentPos, $tokenOffset - $contentPos )
- ) );
- $foundStart = false;
- } else {
- # Non-matching end, write it out
- $output .= substr( $subject, $inputPos, $tokenOffset + $tokenLength - $outputPos );
- }
- $inputPos = $outputPos = $tokenOffset + $tokenLength;
- } else {
- throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
- }
- }
- if ( $outputPos < strlen( $subject ) ) {
- $output .= substr( $subject, $outputPos );
- }
-
- return $output;
- }
-
- /**
- * Perform an operation equivalent to
- *
- * preg_replace( "!$startDelim(.*)$endDelim!$flags", $replace, $subject )
- *
- * @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 string $subject String to search
- * @param string $flags Regular expression flags
- * @return string The string with the matches replaced
- */
- static function delimiterReplace( $startDelim, $endDelim, $replace, $subject, $flags = '' ) {
- $replacer = new RegexlikeReplacer( $replace );
-
- return self::delimiterReplaceCallback( $startDelim, $endDelim,
- $replacer->cb(), $subject, $flags );
- }
-
- /**
- * More or less "markup-safe" explode()
- * Ignores any instances of the separator inside <...>
- * @param string $separator
- * @param string $text
- * @return array
- */
- static function explodeMarkup( $separator, $text ) {
- $placeholder = "\x00";
-
- // Remove placeholder instances
- $text = str_replace( $placeholder, '', $text );
-
- // Replace instances of the separator inside HTML-like tags with the placeholder
- $replacer = new DoubleReplacer( $separator, $placeholder );
- $cleaned = StringUtils::delimiterReplaceCallback( '<', '>', $replacer->cb(), $text );
-
- // Explode, then put the replaced separators back in
- $items = explode( $separator, $cleaned );
- foreach ( $items as $i => $str ) {
- $items[$i] = str_replace( $placeholder, $separator, $str );
- }
-
- return $items;
- }
-
- /**
- * Escape a string to make it suitable for inclusion in a preg_replace()
- * replacement parameter.
- *
- * @param string $string
- * @return string
- */
- static function escapeRegexReplacement( $string ) {
- $string = str_replace( '\\', '\\\\', $string );
- $string = str_replace( '$', '\\$', $string );
-
- return $string;
- }
-
- /**
- * Workalike for explode() with limited memory usage.
- * Returns an Iterator
- * @param string $separator
- * @param string $subject
- * @return ArrayIterator|ExplodeIterator
- */
- static function explode( $separator, $subject ) {
- if ( substr_count( $subject, $separator ) > 1000 ) {
- return new ExplodeIterator( $separator, $subject );
- } else {
- return new ArrayIterator( explode( $separator, $subject ) );
- }
- }
-}
-
-/**
- * Base class for "replacers", objects used in preg_replace_callback() and
- * StringUtils::delimiterReplaceCallback()
- */
-class Replacer {
- /**
- * @return array
- */
- function cb() {
- return array( &$this, 'replace' );
- }
-}
-
-/**
- * Class to replace regex matches with a string similar to that used in preg_replace()
- */
-class RegexlikeReplacer extends Replacer {
- private $r;
-
- /**
- * @param string $r
- */
- function __construct( $r ) {
- $this->r = $r;
- }
-
- /**
- * @param array $matches
- * @return string
- */
- function replace( $matches ) {
- $pairs = array();
- foreach ( $matches as $i => $match ) {
- $pairs["\$$i"] = $match;
- }
-
- return strtr( $this->r, $pairs );
- }
-}
-
-/**
- * Class to perform secondary replacement within each replacement string
- */
-class DoubleReplacer extends Replacer {
- /**
- * @param mixed $from
- * @param mixed $to
- * @param int $index
- */
- function __construct( $from, $to, $index = 0 ) {
- $this->from = $from;
- $this->to = $to;
- $this->index = $index;
- }
-
- /**
- * @param array $matches
- * @return mixed
- */
- function replace( $matches ) {
- return str_replace( $this->from, $this->to, $matches[$this->index] );
- }
-}
-
-/**
- * Class to perform replacement based on a simple hashtable lookup
- */
-class HashtableReplacer extends Replacer {
- private $table, $index;
-
- /**
- * @param array $table
- * @param int $index
- */
- function __construct( $table, $index = 0 ) {
- $this->table = $table;
- $this->index = $index;
- }
-
- /**
- * @param array $matches
- * @return mixed
- */
- function replace( $matches ) {
- return $this->table[$matches[$this->index]];
- }
-}
-
-/**
- * Replacement array for FSS with fallback to strtr()
- * Supports lazy initialisation of FSS resource
- */
-class ReplacementArray {
- private $data = false;
- private $fss = false;
-
- /**
- * Create an object with the specified replacement array
- * The array should have the same form as the replacement array for strtr()
- * @param array $data
- */
- function __construct( $data = array() ) {
- $this->data = $data;
- }
-
- /**
- * @return array
- */
- function __sleep() {
- return array( 'data' );
- }
-
- function __wakeup() {
- $this->fss = false;
- }
-
- /**
- * Set the whole replacement array at once
- * @param array $data
- */
- function setArray( $data ) {
- $this->data = $data;
- $this->fss = false;
- }
-
- /**
- * @return array|bool
- */
- function getArray() {
- return $this->data;
- }
-
- /**
- * Set an element of the replacement array
- * @param string $from
- * @param string $to
- */
- function setPair( $from, $to ) {
- $this->data[$from] = $to;
- $this->fss = false;
- }
-
- /**
- * @param array $data
- */
- function mergeArray( $data ) {
- $this->data = array_merge( $this->data, $data );
- $this->fss = false;
- }
-
- /**
- * @param ReplacementArray $other
- */
- function merge( $other ) {
- $this->data = array_merge( $this->data, $other->data );
- $this->fss = false;
- }
-
- /**
- * @param string $from
- */
- function removePair( $from ) {
- unset( $this->data[$from] );
- $this->fss = false;
- }
-
- /**
- * @param array $data
- */
- function removeArray( $data ) {
- foreach ( $data as $from => $to ) {
- $this->removePair( $from );
- }
- $this->fss = false;
- }
-
- /**
- * @param string $subject
- * @return string
- */
- function replace( $subject ) {
- if ( function_exists( 'fss_prep_replace' ) ) {
- wfProfileIn( __METHOD__ . '-fss' );
- if ( $this->fss === false ) {
- $this->fss = fss_prep_replace( $this->data );
- }
- $result = fss_exec_replace( $this->fss, $subject );
- wfProfileOut( __METHOD__ . '-fss' );
- } else {
- wfProfileIn( __METHOD__ . '-strtr' );
- $result = strtr( $subject, $this->data );
- wfProfileOut( __METHOD__ . '-strtr' );
- }
-
- return $result;
- }
-}
-
-/**
- * An iterator which works exactly like:
- *
- * foreach ( explode( $delim, $s ) as $element ) {
- * ...
- * }
- *
- * Except it doesn't use 193 byte per element
- */
-class ExplodeIterator implements Iterator {
- // The subject string
- private $subject, $subjectLength;
-
- // The delimiter
- private $delim, $delimLength;
-
- // The position of the start of the line
- private $curPos;
-
- // The position after the end of the next delimiter
- private $endPos;
-
- // The current token
- private $current;
-
- /**
- * Construct a DelimIterator
- * @param string $delim
- * @param string $subject
- */
- function __construct( $delim, $subject ) {
- $this->subject = $subject;
- $this->delim = $delim;
-
- // Micro-optimisation (theoretical)
- $this->subjectLength = strlen( $subject );
- $this->delimLength = strlen( $delim );
-
- $this->rewind();
- }
-
- function rewind() {
- $this->curPos = 0;
- $this->endPos = strpos( $this->subject, $this->delim );
- $this->refreshCurrent();
- }
-
- function refreshCurrent() {
- if ( $this->curPos === false ) {
- $this->current = false;
- } elseif ( $this->curPos >= $this->subjectLength ) {
- $this->current = '';
- } elseif ( $this->endPos === false ) {
- $this->current = substr( $this->subject, $this->curPos );
- } else {
- $this->current = substr( $this->subject, $this->curPos, $this->endPos - $this->curPos );
- }
- }
-
- function current() {
- return $this->current;
- }
-
- /**
- * @return int|bool Current position or boolean false if invalid
- */
- function key() {
- return $this->curPos;
- }
-
- /**
- * @return string
- */
- function next() {
- if ( $this->endPos === false ) {
- $this->curPos = false;
- } else {
- $this->curPos = $this->endPos + $this->delimLength;
- if ( $this->curPos >= $this->subjectLength ) {
- $this->endPos = false;
- } else {
- $this->endPos = strpos( $this->subject, $this->delim, $this->curPos );
- }
- }
- $this->refreshCurrent();
-
- return $this->current;
- }
-
- /**
- * @return bool
- */
- function valid() {
- return $this->curPos !== false;
- }
-}