From 1d2dc36ac1baca6ff63f2a082cc7d4c6439fc1de Mon Sep 17 00:00:00 2001
From: Tim Starling <tstarling@users.mediawiki.org>
Date: Tue, 21 Nov 2006 10:38:07 +0000
Subject: [PATCH] Collection of generic string functions and classes

---
 includes/StringUtils.php | 263 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 263 insertions(+)
 create mode 100644 includes/StringUtils.php

diff --git a/includes/StringUtils.php b/includes/StringUtils.php
new file mode 100644
index 0000000000..8a0e478c81
--- /dev/null
+++ b/includes/StringUtils.php
@@ -0,0 +1,263 @@
+<?php
+
+class StringUtils {
+	/**
+	 * 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.
+	 */
+	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 staticDelimiterReplace but uses far less
+	 * memory and allows regular expression delimiters.
+	 *
+	 * @param string $flags Regular expression flags
+	 */
+	static function delimiterReplaceCallback( $startDelim, $endDelim, $callback, $subject, $flags = '' ) {
+		$inputPos = 0;
+		$outputPos = 0;
+		$output = '';
+		$foundStart = false;
+
+		while ( $inputPos < strlen( $subject ) && 
+		  preg_match( "!($startDelim)|($endDelim)!$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) ) 
+		{
+			if ( $m[1][0] != '' ) {
+				# Found start
+				# Write out the non-matching section
+				$output .= substr( $subject, $outputPos, $m[1][1] - $outputPos );
+				$foundStart = true;
+				$inputPos = $contentPos = $m[1][1] + strlen( $m[1][0] );
+				$outputPos = $m[1][1];
+			} elseif ( $m[2][0] != '' ) {
+				# Found end
+				if ( $foundStart ) {
+					# Found match
+					$output .= call_user_func( $callback, array(
+						substr( $subject, $outputPos, $m[2][1] + strlen( $m[2][0] ) - $outputPos ),
+						substr( $subject, $contentPos, $m[2][1] - $contentPos )
+					));
+					$foundStart = false;
+				} else {
+					# Non-matching end, write it out
+					$output .= substr( $subject, $inputPos, $m[2][1] + strlen( $m[2][0] ) - $outputPos );
+				}
+				$inputPos = $outputPos = $m[2][1] + strlen( $m[2][0] );
+			} 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
+	 * @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 $string;
+	}
+}
+
+/**
+ * Base class for "replacers", objects used in preg_replace_callback() and 
+ * StringUtils::delimiterReplaceCallback()
+ */
+class Replacer {
+	function cb() {
+		return array( &$this, 'replace' );
+	}
+}
+
+/**
+ * Class to replace regex matches with a string similar to that used in preg_replace()
+ */
+class RegexlikeReplacer extends Replacer {
+	var $r;
+	function __construct( $r ) {
+		$this->r = $r;
+	}
+
+	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 {
+	function __construct( $from, $to, $index = 0 ) {
+		$this->from = $from;
+		$this->to = $to;
+		$this->index = $index;
+	}
+	
+	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 {
+	var $table, $index;
+
+	function __construct( $table, $index = 0 ) {
+		$this->table = $table;
+		$this->index = $index;
+	}
+
+	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 {
+	/*mostly private*/ var $data = false;
+	/*mostly private*/ var $fss = false;
+
+	/**
+	 * Create an object with the specified replacement array
+	 * The array should have the same form as the replacement array for strtr()
+	 */
+	function __construct( $data = array() ) {
+		$this->data = $data;
+	}
+
+	function __sleep() {
+		return array( 'data' );
+	}
+
+	function __wakeup() {
+		$this->fss = false;
+	}
+
+	/**
+	 * Set the whole replacement array at once
+	 */
+	function setArray( $data ) {
+		$this->data = $data;
+		$this->fss = false;
+	}
+
+	function getArray() {
+		return $this->data;
+	}
+
+	/**
+	 * Set an element of the replacement array
+	 */
+	function setPair( $from, $to ) {
+		$this->data[$from] = $to;
+		$this->fss = false;
+	}
+
+	function mergeArray( $data ) {
+		$this->data = array_merge( $this->data, $data );
+		$this->fss = false;
+	}
+
+	function merge( $other ) {
+		$this->data = array_merge( $this->data, $other->data );
+		$this->fss = false;
+	}
+
+	function replace( $subject ) {
+		if ( function_exists( 'fss_prep_replace' ) ) {
+			if ( $this->fss === false ) {
+				$this->fss = fss_prep_replace( $this->data );
+			}
+			return fss_exec_replace( $this->fss, $subject );
+		} else {
+			return strtr( $subject, $this->data );
+		}
+	}
+}
+
+?>
-- 
2.20.1