From abfdd38e59458d871f466952776675238f3179fb Mon Sep 17 00:00:00 2001
From: Michael Foster <savetheinternet@tinyboard.org>
Date: Mon, 19 Aug 2013 23:47:56 +1000
Subject: Unicode bi-directional text: Finally a working fix

---
 inc/display.php | 45 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

(limited to 'inc/display.php')

diff --git a/inc/display.php b/inc/display.php
index 6fa97f4f..81f8c53d 100644
--- a/inc/display.php
+++ b/inc/display.php
@@ -218,11 +218,50 @@ function truncate($body, $url, $max_lines = false, $max_chars = false) {
 	return $body;
 }
 
-function bidi_cleanup($str) {
-	// Removes all embedded RTL and LTR unicode formatting blocks in a string so that
+function bidi_cleanup($data) {
+	// Closes all embedded RTL and LTR unicode formatting blocks in a string so that
 	// it can be used inside another without controlling its direction.
 
-	return "<bdi>$str</bdi>";
+	$explicits	= '\xE2\x80\xAA|\xE2\x80\xAB|\xE2\x80\xAD|\xE2\x80\xAE';
+	$pdf		= '\xE2\x80\xAC';
+	
+	preg_match_all("!$explicits!",	$data, $m1, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
+	preg_match_all("!$pdf!", 	$data, $m2, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
+	
+	if (count($m1) || count($m2)){
+	
+		$p = array();
+		foreach ($m1 as $m){ $p[$m[0][1]] = 'push'; }
+		foreach ($m2 as $m){ $p[$m[0][1]] = 'pop'; }
+		ksort($p);
+	
+		$offset = 0;
+		$stack = 0;
+		foreach ($p as $pos => $type){
+	
+			if ($type == 'push'){
+				$stack++;
+			}else{
+				if ($stack){
+					$stack--;
+				}else{
+					# we have a pop without a push - remove it
+					$data = substr($data, 0, $pos-$offset)
+						.substr($data, $pos+3-$offset);
+					$offset += 3;
+				}
+			}
+		}
+	
+		# now add some pops if your stack is bigger than 0
+		for ($i=0; $i<$stack; $i++){
+			$data .= "\xE2\x80\xAC";
+		}
+	
+		return $data;
+	}
+	
+	return $data;
 }
 
 function secure_link_confirm($text, $title, $confirm_message, $href) {
-- 
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