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deps/g3dlite/include/G3D/AreaMemoryManager.h

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+/**
+ \file AreaMemoryManager.h
+  
+ \maintainer Morgan McGuire, http://graphics.cs.williams.edu
+
+ \created 2009-01-20
+ \edited  2010-10-29
+
+ Copyright 2000-2012, Morgan McGuire.
+ All rights reserved.
+ */
+
+
+#ifndef G3D_AreaMemoryManager_h
+#define G3D_AreaMemoryManager_h
+
+#include "G3D/platform.h"
+#include "G3D/g3dmath.h"
+#include "G3D/Array.h"
+#include "G3D/MemoryManager.h"
+
+namespace G3D {
+
+/** 
+  \brief Allocates memory in large blocks and then frees it as an area.
+
+  Useful for ensuring cache coherence and for reducing the time cost of 
+  multiple allocations and deallocations.
+
+  <b>Not threadsafe</b>
+ */
+class AreaMemoryManager : public MemoryManager {
+private:
+
+    class Buffer {
+    private:
+        uint8*              m_first;
+        size_t              m_size;
+        size_t              m_used;
+
+    public:
+
+        Buffer(size_t size);
+
+        ~Buffer();
+
+        /** Returns NULL if out of space */
+        void* alloc(size_t s);
+    };
+    
+    size_t                  m_sizeHint;
+
+    /** The underlying array is stored in regular MemoryManager heap memory */
+    Array<Buffer*>          m_bufferArray;
+
+    AreaMemoryManager(size_t sizeHint);
+
+public:
+
+    typedef shared_ptr<AreaMemoryManager> Ref;
+
+    /** 
+        \param sizeHint Total amount of memory expected to be allocated.
+        The allocator will allocate memory from the system in increments
+        of this size.
+    */
+    static AreaMemoryManager::Ref create(size_t sizeHint = 10 * 1024 * 1024);
+
+    /** Invokes deallocateAll. */
+    ~AreaMemoryManager();
+
+    size_t bytesAllocated() const;
+
+    /** Allocates memory out of the buffer pool. 
+        @param s must be no larger than sizeHint */
+    virtual void* alloc(size_t s);
+
+    /** Ignored. */
+    virtual void free(void* x);
+
+    virtual bool isThreadsafe() const;
+
+    /** Deletes all previously allocated memory. Because delete is not
+        invoked on objects in this memory, it is not safe to simply
+        free memory containing C++ objects that expect their destructors
+        to be called. */
+    void deallocateAll();
+};
+
+typedef AreaMemoryManager CoherentAllocator;
+}
+
+#endif