The Golden Code

git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@31 7ec92016-0320-0410-acc4-a06ded1c099a

Reference/Singleton.cpp

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+////////////////////////////////////////////////////////////////////////////////
+// The Loki Library
+// Copyright (c) 2001 by Andrei Alexandrescu
+// This code accompanies the book:
+// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design 
+//     Patterns Applied". Copyright (c) 2001. Addison-Wesley.
+// Permission to use, copy, modify, distribute and sell this software for any 
+//     purpose is hereby granted without fee, provided that the above copyright 
+//     notice appear in all copies and that both that copyright notice and this 
+//     permission notice appear in supporting documentation.
+// The author or Addison-Wesley Longman make no representations about the 
+//     suitability of this software for any purpose. It is provided "as is" 
+//     without express or implied warranty.
+////////////////////////////////////////////////////////////////////////////////
+
+// Last update: June 20, 2001
+
+#include "Singleton.h"
+
+using namespace Loki::Private;
+
+Loki::Private::TrackerArray Loki::Private::pTrackerArray = 0;
+unsigned int Loki::Private::elements = 0;
+
+////////////////////////////////////////////////////////////////////////////////
+// function AtExitFn
+// Ensures proper destruction of objects with longevity
+////////////////////////////////////////////////////////////////////////////////
+
+void Loki::Private::AtExitFn()
+{
+    assert(elements > 0 && pTrackerArray != 0);
+    // Pick the element at the top of the stack
+    LifetimeTracker* pTop = pTrackerArray[elements - 1];
+    // Remove that object off the stack
+    // Don't check errors - realloc with less memory 
+    //     can't fail
+    pTrackerArray = static_cast<TrackerArray>(std::realloc(
+        pTrackerArray, sizeof(*pTrackerArray) * --elements));
+    // Destroy the element
+    delete pTop;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Change log:
+// June 20, 2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!!
+// January 10, 2002: Fixed bug in call to realloc - credit due to Nigel Gent and
+//      Eike Petersen
+// May 08, 2002: Refixed bug in call to realloc
+////////////////////////////////////////////////////////////////////////////////