diff --git a/inc/common.php b/inc/common.php
index ca05bd3e78f553236bb46a9a462d51707ac51e23..4d52c0ee69c747410213c906c62456e0875e3d1e 100644
--- a/inc/common.php
+++ b/inc/common.php
@@ -950,9 +950,10 @@ function getRevisionInfo($id,$rev){
   // one line with one same timestamp
   $loglines_matching = array();
   $loglines_matching[] =  $loglines[$index];
-  for ($i=$index-1;hasTimestamp($loglines[$i], $rev) == 0; $i--)
+  for ($i=$index-1;$i>=0 && hasTimestamp($loglines[$i], $rev) == 0; $i--)
     $loglines_matching[] = $loglines[$i];
-  for ($i=$index+1;hasTimestamp($loglines[$i], $rev) == 0; $i++)
+  $logsize = count($loglines);
+  for ($i=$index+1;$i<$logsize && hasTimestamp($loglines[$i], $rev) == 0; $i++)
     $loglines_matching[] = $loglines[$i];
 
   // Match only lines concerning the document $id