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public/vallocator.h

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//
+//=============================================================================//
+
+// These classes let you write your own allocators to be used with new and delete.
+// If you have an allocator: VAllocator *pAlloc, you can call new and delete like this:
+//
+// ptr = VNew(pAlloc) ClassName;
+// VDelete(pAlloc, ptr);
+//
+// Note: allocating and freeing arrays of objects will not work using VAllocators.
+
+
+
+#ifndef VALLOCATOR_H
+#define VALLOCATOR_H
+
+
+class VAllocator
+{
+public:
+	virtual void*	Alloc(unsigned long size)=0;
+	virtual void	Free(void *ptr)=0;
+};
+
+
+// This allocator just uses malloc and free.
+class VStdAllocator : public VAllocator
+{
+public:
+	virtual void*	Alloc(unsigned long size);
+	virtual void	Free(void *ptr);
+};
+extern VStdAllocator g_StdAllocator;
+
+
+
+// Use these to allocate classes through VAllocator.
+// Allocating arrays of classes is not supported.
+#define VNew(pAlloc)				new 
+#define VDelete(pAlloc, ptr)		delete ptr
+
+// Used internally.. just makes sure we call the right operator new.
+class DummyAllocatorHelper
+{
+public:
+	int x;
+};
+
+inline void* operator new(size_t size, void *ptr, DummyAllocatorHelper *asdf)
+{
+	(void)asdf;	// Suppress unused-variable compiler warnings.
+	(void)size;
+	return ptr;
+}
+
+inline void operator delete(void *ptrToDelete, void *ptr, DummyAllocatorHelper *asdf)
+{
+	(void)asdf;	// Suppress unused-variable compiler warnings.
+	(void)ptr;
+	(void)ptrToDelete;
+}
+
+// Use these to manually construct and destruct lists of objects.
+template<class T>
+inline void VAllocator_CallConstructors(T *pObjects, int count=1)
+{
+	for(int i=0; i < count; i++)
+		new(&pObjects[i], (DummyAllocatorHelper*)0) T;
+}
+
+template<class T>
+inline void VAllocator_CallDestructors(T *pObjects, int count)
+{
+	for(int i=0; i < count; i++)
+		pObjects[i].~T();
+}
+
+#endif
+