--- /dev/null
+<?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.
+ *
+ * @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.
+ *
+ * @since 1.21
+ * @param string $value String to check
+ * @return bool Whether the given $value is a valid UTF-8 encoded string
+ */
+ static function isUtf8( $value ) {
+ $value = (string)$value;
+
+ // HHVM 3.4 and older come with an outdated version of libmbfl that
+ // incorrectly allows values above U+10FFFF, so we have to check
+ // for them separately. (This issue also exists in PHP 5.3 and
+ // older, which are no longer supported.)
+ 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 );
+ }
+
+ /**
+ * Explode a string, but ignore any instances of the separator inside
+ * the given start and end delimiters, which may optionally nest.
+ * The delimiters are literal strings, not regular expressions.
+ * @param string $startDelim Start delimiter
+ * @param string $endDelim End delimiter
+ * @param string $separator Separator string for the explode.
+ * @param string $subject Subject string to explode.
+ * @param bool $nested True iff the delimiters are allowed to nest.
+ * @return ArrayIterator
+ */
+ static function delimiterExplode( $startDelim, $endDelim, $separator,
+ $subject, $nested = false ) {
+ $inputPos = 0;
+ $lastPos = 0;
+ $depth = 0;
+ $encStart = preg_quote( $startDelim, '!' );
+ $encEnd = preg_quote( $endDelim, '!' );
+ $encSep = preg_quote( $separator, '!' );
+ $len = strlen( $subject );
+ $m = [];
+ $exploded = [];
+ while (
+ $inputPos < $len &&
+ preg_match(
+ "!$encStart|$encEnd|$encSep!S", $subject, $m,
+ PREG_OFFSET_CAPTURE, $inputPos
+ )
+ ) {
+ $match = $m[0][0];
+ $matchPos = $m[0][1];
+ $inputPos = $matchPos + strlen( $match );
+ if ( $match === $separator ) {
+ if ( $depth === 0 ) {
+ $exploded[] = substr(
+ $subject, $lastPos, $matchPos - $lastPos
+ );
+ $lastPos = $inputPos;
+ }
+ } elseif ( $match === $startDelim ) {
+ if ( $depth === 0 || $nested ) {
+ $depth++;
+ }
+ } else {
+ $depth--;
+ }
+ }
+ $exploded[] = substr( $subject, $lastPos );
+ // This method could be rewritten in the future to avoid creating an
+ // intermediate array, since the return type is just an iterator.
+ return new ArrayIterator( $exploded );
+ }
+
+ /**
+ * Perform an operation equivalent to `preg_replace()`
+ *
+ * Matches this code:
+ *
+ * preg_replace( "!$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 $output;
+ }
+
+ /**
+ * Perform an operation equivalent to `preg_replace_callback()`
+ *
+ * Matches this code:
+ *
+ * preg_replace_callback( "!$startDelim(.*)$endDelim!s$flags", $callback, $subject );
+ *
+ * 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/`.
+ *
+ * The implementation of delimiterReplaceCallback() is slower than hungryDelimiterReplace()
+ * but uses far less memory. The delimiters are literal strings, not regular expressions.
+ *
+ * @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 InvalidArgumentException
+ * @return string
+ */
+ static function delimiterReplaceCallback( $startDelim, $endDelim, $callback,
+ $subject, $flags = ''
+ ) {
+ $inputPos = 0;
+ $outputPos = 0;
+ $contentPos = 0;
+ $output = '';
+ $foundStart = false;
+ $encStart = preg_quote( $startDelim, '!' );
+ $encEnd = preg_quote( $endDelim, '!' );
+ $strcmp = strpos( $flags, 'i' ) === false ? 'strcmp' : 'strcasecmp';
+ $endLength = strlen( $endDelim );
+ $m = [];
+
+ 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 InvalidArgumentException( '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, [
+ 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 InvalidArgumentException( 'Invalid delimiter given to ' . __METHOD__ );
+ }
+ }
+ if ( $outputPos < strlen( $subject ) ) {
+ $output .= substr( $subject, $outputPos );
+ }
+
+ return $output;
+ }
+
+ /**
+ * Perform an operation equivalent to `preg_replace()` with flags.
+ *
+ * Matches this code:
+ *
+ * preg_replace( "!$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 = self::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;
+ }
+
+ /**
+ * More or less "markup-safe" str_replace()
+ * Ignores any instances of the separator inside `<...>`
+ * @param string $search
+ * @param string $replace
+ * @param string $text
+ * @return string
+ */
+ static function replaceMarkup( $search, $replace, $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( $search, $placeholder );
+ $cleaned = self::delimiterReplaceCallback( '<', '>', $replacer->cb(), $text );
+
+ // Explode, then put the replaced separators back in
+ $cleaned = str_replace( $search, $replace, $cleaned );
+ $text = str_replace( $placeholder, $search, $cleaned );
+
+ return $text;
+ }
+
+ /**
+ * 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.
+ *
+ * @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 ) );
+ }
+ }
+}
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