From c6011941511e706c3a3d44151eccda7d0b472007 Mon Sep 17 00:00:00 2001
From: Andrey Andreev <narf@devilix.net>
Date: Thu, 11 Feb 2016 23:49:37 +0200
Subject: Fix #4449

---
 system/database/DB_query_builder.php | 60 ++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 26 deletions(-)

(limited to 'system/database')

diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index d6f35e0df..6bf039ead 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -531,38 +531,46 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 
 		is_bool($escape) OR $escape = $this->_protect_identifiers;
 
-		// Split multiple conditions
-		if ($escape === TRUE && preg_match_all('/\sAND\s|\sOR\s/i', $cond, $m, PREG_OFFSET_CAPTURE))
+		if ( ! $this->_has_operator($cond))
 		{
-			$newcond = '';
-			$m[0][] = array('', strlen($cond));
-
-			for ($i = 0, $c = count($m[0]), $s = 0;
-				$i < $c;
-				$s = $m[0][$i][1] + strlen($m[0][$i][0]), $i++)
-			{
-				$temp = substr($cond, $s, ($m[0][$i][1] - $s));
-				$newcond .= preg_match("/(\(*)?([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $temp, $match)
-						? $match[1].$this->protect_identifiers($match[2]).$match[3].$this->protect_identifiers($match[4])
-						: $temp;
-
-				$newcond .= $m[0][$i][0];
-			}
-
-			$cond = ' ON '.$newcond;
-		}
-		// Split apart the condition and protect the identifiers
-		elseif ($escape === TRUE && preg_match("/(\(*)?([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $cond, $match))
-		{
-			$cond = ' ON '.$match[1].$this->protect_identifiers($match[2]).$match[3].$this->protect_identifiers($match[4]);
+			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
 		}
-		elseif ( ! $this->_has_operator($cond))
+		elseif ($escape === FALSE)
 		{
-			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
+			$cond = ' ON '.$cond;
 		}
 		else
 		{
-			$cond = ' ON '.$cond;
+			// Split multiple conditions
+			if (preg_match_all('/\sAND\s|\sOR\s/i', $cond, $joints, PREG_OFFSET_CAPTURE))
+			{
+				$conditions = array();
+				$joints = $joints[0];
+				array_unshift($joints, array('', 0));
+
+				for ($i = count($joints) - 1, $pos = strlen($cond); $i >= 0; $i--)
+				{
+					$joints[$i][1] += strlen($joints[$i][0]); // offset
+					$conditions[$i] = substr($cond, $joints[$i][1], $pos - $joints[$i][1]);
+					$pos = $joints[$i][1] - strlen($joints[$i][0]);
+					$joints[$i] = $joints[$i][0];
+				}
+			}
+			else
+			{
+				$conditions = array($cond);
+				$joints = array('');
+			}
+
+			$cond = ' ON ';
+			for ($i = 0, $c = count($conditions); $i < $c; $i++)
+			{
+				$operator = $this->_get_operator($conditions[$i]);
+				$cond .= $joints[$i];
+				$cond .= preg_match("/(\(*)?([\[\]\w\.'-]+)".preg_quote($operator)."(.*)/i", $conditions[$i], $match)
+					? $match[1].$this->protect_identifiers($match[2]).$operator.$this->protect_identifiers($match[3])
+					: $conditions[$i];
+			}
 		}
 
 		// Do we want to escape the table name?
-- 
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