From 625060d503a1b7eb081c175122c6a73c1f7b2404 Mon Sep 17 00:00:00 2001
From: Nathan Gass
Date: Mon, 22 Jan 2007 13:30:10 +0000
Subject: added and documented regex functions from search_regex.class

---
 it.class | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/it.class b/it.class
index 149ec04..f865858 100644
--- a/it.class
+++ b/it.class
@@ -163,6 +163,105 @@ function toascii($text)
 		array('ä' => 'ae', 'ö' => 'oe', 'ü' => 'ue', 'Ä' => 'Ae', 'Ö' => 'Oe', 'Ü' => 'Ue', 'æ' => 'ae', 'Æ' => 'Ae', 'ß' => 'ss'));
 }
 
+
+/**
+ * Convert regex for preg (redefines \w,\W,\b,\B, adds and escapes delimiter, adds modifiers)
+ * @param $pattern Regex to convert
+ * @param named parameter casesensitive Regex is case sensitive (omit modifier i)
+ * @param named parameter multiline add modifier m
+ * @param named parameter singleline add modifier s
+ * @param named parameter utf8 add modifier u
+ * @param named parameter extended add modifier x
+ * @return converted regex to use with preg
+ */
+function convertregex( $pattern, $p = array() )
+{
+	$wordchar = 'a-zA-Z0-9_\xa0-\xff';
+	$nonwordchar = '\x00-\x2f\x3a-\x40\x5B-\x60\x7b-\x9f';
+	
+	#matches only even number of backslashes (double escaped for php and preg)
+	$nonesc = '(?<!\\\\)(?:\\\\\\\\)*';
+	
+	#matches unescaped '[' until unescaped and not starting ']', starting ] as in []gna] or [^]gna]
+	$incharclass = "$nonesc\\[\\^?\\]?(?:[^]]|$nonesc\\\\])*";
+	
+	$pattern = preg_replace( "|/|", '\/', $pattern ); 
+	$replaces = array( 
+		# \w in character class
+		"/($incharclass$nonesc)\\\\w/" => "\$1$wordchar",
+		# \W in character class
+		"/($incharclass$nonesc)\\\\W/" => "\$1$nonwordchar",
+		# normal \w
+		"/($nonesc)\\\\w/" => "\$1[$wordchar]",
+		# normal \W
+		"/($nonesc)\\\\W/" => "\$1[$nonwordchar]",
+		# \b (use negative assertions to match at end of string)
+		"/($nonesc)\\\\b/" => "\$1(?:(?<![$wordchar])(?![$nonwordchar])|(?<![$nonwordchar])(?![$wordchar]))",
+		# \B (use positive assertions to not match at end of string)
+		"/($nonesc)\\\\B/" => "\$1(?:(?<=[$wordchar])(?=[$wordchar])|(?<=[$nonwordchar])(?=[$nonwordchar]))",
+		);
+	$pattern = preg_replace( array_keys( $replaces ), array_values( $replaces ), $pattern );
+	if( ! $p['casesensitive'] )
+		$modifiers .= 'i';
+	foreach( array(
+		'multiline'  => 'm',
+		'singleline' => 's',
+		'utf8'       => 'u',
+		'extended'   => 'x',
+		) as $key => $mod )
+		if( $p[$key] )
+			$moifiers .= $mod;
+	return  "/" . $pattern . "/" . $modifiers;
+}
+
+/**
+ * Try to match string against regex. See convertregex for additional named parameters.
+ * @param $pattern Regex to match against
+ * @param $string String to match
+ * @param named parameter offset_capture Set flag preg_offset_capture (returns offsets with the matches).
+ * @param named parameter all Return every match as array instead of first match.
+ * @return Matched string or false 
+ */
+function match( $pattern, $string, $p = array() )
+{
+	$flags = 0;
+	if( $p['offset_capture'] )
+		$flags |= PREG_OFFSET_CAPTURE;
+	if( $p['all'] )
+		$r = preg_match_all( it::convertregex( $pattern, $p ), $string, $m, $flags | PREG_PATTERN_ORDER, $p['offset'] );
+	else
+		$r = preg_match( it::convertregex( $pattern, $p ), $string, $m, $flags, $p['offset'] );
+	# no match
+	if( !$r )
+		return false;
+	# no capture
+	else if( count( $m ) == 1 )
+		return $m[0];
+	# one capture
+	else if( count( $m ) == 2 )
+		return $m[1];
+	# captures, reorder pattern_order to set_order but without first element
+	else if( $p['all'] && !$p['pattern_order'] )
+		return call_user_func_array( 'array_map', array_merge( array( null ), array_slice( $m, 1 ) ) );
+	# captures, don't return first element (matched string)
+	else 
+		return array_slice( $m, 1 );
+}
+
+/**
+ * Replace parts of a string matched by a pattern with according replacement string. See convertregex for named parameters.
+ * @param $replacementes Array with patterns as keys and replacement strings as values.
+ * @param $string String to change.
+ * @return New string.
+ */
+function replace( $replacements, $string, $p = array() )
+{
+	$patterns = array();
+	foreach( array_keys( $replacements ) as $pat ) 
+		$patterns[] = it::convertregex( $pat, $p );
+	return preg_replace( $patterns, array_values( $replacements ), $string, isset( $p['limit'] ) ? $p['limit'] : -1 );
+}
+
 }
 
 ?>
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