X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=simgear%2Fstructure%2FSGAtomic.hxx;h=a7977fc31408483332cb004c026a59bd6cbb2d3c;hb=7e7d877874fcd67cad0152bd1a2a073e0337235f;hp=4029f3527fb91938f0871ee8670e454118faf93e;hpb=0c8358ae67e218b3cd3a0332bd9d8c7be0521af3;p=simgear.git

diff --git a/simgear/structure/SGAtomic.hxx b/simgear/structure/SGAtomic.hxx
index 4029f352..a7977fc3 100644
--- a/simgear/structure/SGAtomic.hxx
+++ b/simgear/structure/SGAtomic.hxx
@@ -1,6 +1,6 @@
 /* -*-c++-*-
  *
- * Copyright (C) 2005-2006 Mathias Froehlich 
+ * Copyright (C) 2005-2009 Mathias Froehlich 
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -81,7 +81,25 @@ public:
     SGGuard<SGMutex> lock(mMutex);
     return mValue;
 #endif
- }
+  }
+
+  bool compareAndExchange(unsigned oldValue, unsigned newValue)
+  {
+#if defined(SGATOMIC_USE_GCC4_BUILTINS)
+    return __sync_bool_compare_and_swap(&mValue, oldValue, newValue);
+#elif defined(SGATOMIC_USE_MIPOSPRO_BUILTINS)
+    return __compare_and_swap(&mValue, oldValue, newValue);
+#elif defined(SGATOMIC_USE_WIN32_INTERLOCKED)
+    long volatile* lvPtr = reinterpret_cast<long volatile*>(&mValue);
+    return oldValue == InterlockedCompareExchange(lvPtr, newValue, oldValue);
+#else
+    SGGuard<SGMutex> lock(mMutex);
+    if (mValue != oldValue)
+      return false;
+    mValue = newValue;
+    return true;
+#endif
+  }
 
 private:
   SGAtomic(const SGAtomic&);
@@ -91,11 +109,37 @@ private:
   && !defined(SGATOMIC_USE_MIPOSPRO_BUILTINS) \
   && !defined(SGATOMIC_USE_WIN32_INTERLOCKED)
   mutable SGMutex mMutex;
-#endif
-#ifdef SGATOMIC_USE_WIN32_INTERLOCKED
-  __declspec(align(32))
 #endif
   unsigned mValue;
 };
 
+namespace simgear
+{
+// Typesafe wrapper around SGSwappable
+template <typename T>
+class Swappable : private SGAtomic
+{
+public:
+    Swappable(const T& value) : SGAtomic(static_cast<unsigned>(value))
+    {
+    }
+    T operator() () const
+    {
+        return static_cast<T>(SGAtomic::operator unsigned ());
+    }
+    Swappable& operator=(const Swappable& rhs)
+    {
+        for (unsigned oldval = unsigned(*this);
+             !compareAndExchange(oldval, unsigned(rhs));
+             oldval = unsigned(*this))
+            ;
+        return *this;
+    }
+    bool compareAndSwap(const T& oldVal, const T& newVal)
+    {
+        return SGAtomic::compareAndExchange(static_cast<unsigned>(oldVal),
+                                           static_cast<unsigned>(newVal));
+    }
+};
+}
 #endif