Resolved issue 48.  Removed unneeded array copy.
diff --git a/system/libraries/Cache/drivers/Cache_file.php b/system/libraries/Cache/drivers/Cache_file.php
index edb48ac..6c37e70 100644
--- a/system/libraries/Cache/drivers/Cache_file.php
+++ b/system/libraries/Cache/drivers/Cache_file.php
@@ -165,8 +165,8 @@
 			}
 
 			return array(
-				'expire' 	=> $mtime + $data['data']['ttl'],
-				'mtime'		=> $mtime
+				'expire' => $mtime + $data['data']['ttl'],
+				'mtime'	 => $mtime
 			);
 		}