BUG: ISstream: only check character if reading succeeded

src/OpenFOAM/db/IOstreams/Sstreams/ISstreamI.H

@@ -2,8 +2,8 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
-     \\/     M anipulation  |
+    \\  /    A nd           | Copyright (C) 2011-2014 OpenFOAM Foundation
+     \\/     M anipulation  | Copyright (C) 2015 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -59,7 +59,7 @@ inline Foam::ISstream& Foam::ISstream::get(char& c)
     is_.get(c);
     setState(is_.rdstate());
 
-    if (c == '\n')
+    if (good() && c == '\n')
     {
         lineNumber_++;
     }