77 lines
1.5 KiB
C++
77 lines
1.5 KiB
C++
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#pragma once
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#include <memory>
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template<class T, size_t NumElementsInReserve>
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class cAllocationPool {
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public:
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class cStarvationCallbacks
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{
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public:
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virtual ~cStarvationCallbacks() {}
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virtual void OnStartingUsingBuffer() = 0;
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virtual void OnStopUsingBuffer() = 0;
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virtual void OnBufferEmpty() = 0;
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};
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cAllocationPool(std::auto_ptr<cStarvationCallbacks> a_Callbacks) :
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m_Callbacks(a_Callbacks)
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{
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}
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~cAllocationPool()
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{
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while (!m_FreeList.empty())
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{
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free (m_FreeList.front());
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m_FreeList.pop_front();
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}
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}
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T* Allocate()
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{
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if (m_FreeList.size() <= NumElementsInReserve)
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{
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void * space = malloc(sizeof(T));
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if (space != NULL)
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{
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return new(space) T;
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}
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else if (m_FreeList.size() == NumElementsInReserve)
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{
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m_Callbacks->OnStartingUsingBuffer();
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}
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else if (m_FreeList.empty())
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{
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m_Callbacks->OnBufferEmpty();
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// Try again until the memory is avalable
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return Allocate();
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}
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}
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// placement new, used to initalize the object
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T* ret = new (m_FreeList.front()) T;
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m_FreeList.pop_front();
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return ret;
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}
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void Free(T* ptr)
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{
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if (ptr == NULL)
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{
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return;
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}
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// placement destruct.
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ptr->~T();
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m_FreeList.push_front(ptr);
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if (m_FreeList.size() == NumElementsInReserve)
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{
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m_Callbacks->OnStopUsingBuffer();
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}
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}
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private:
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std::list<void *> m_FreeList;
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std::auto_ptr<cStarvationCallbacks> m_Callbacks;
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};
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