memory_pool.h

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/*
**  ClanLib SDK
**  Copyright (c) 1997-2009 The ClanLib Team
**
**  This software is provided 'as-is', without any express or implied
**  warranty.  In no event will the authors be held liable for any damages
**  arising from the use of this software.
**
**  Permission is granted to anyone to use this software for any purpose,
**  including commercial applications, and to alter it and redistribute it
**  freely, subject to the following restrictions:
**
**  1. The origin of this software must not be misrepresented; you must not
**     claim that you wrote the original software. If you use this software
**     in a product, an acknowledgment in the product documentation would be
**     appreciated but is not required.
**  2. Altered source versions must be plainly marked as such, and must not be
**     misrepresented as being the original software.
**  3. This notice may not be removed or altered from any source distribution.
**
**  Note: Some of the libraries ClanLib may link to may have additional
**  requirements or restrictions.
**
**  File Author(s):
**
**    Magnus Norddahl
*/



#pragma once


#include "../api_core.h"
#include <new>
#include <memory>

class CL_API_CORE CL_MemoryPool
{

public:
        virtual ~CL_MemoryPool()
        {
        }



public:

        virtual void *alloc(size_t size) = 0;


        virtual void free(void *data) = 0;

        static CL_MemoryPool *get_temp_pool();
};

template<typename _Type>
class CL_MemoryPoolAllocator
{
public:
        typedef _Type value_type;
        typedef value_type* pointer;
        typedef const value_type* const_pointer;
        typedef value_type& reference;
        typedef const value_type& const_reference;
        typedef std::size_t size_type;
        typedef std::ptrdiff_t difference_type;

        CL_MemoryPoolAllocator()
        : _memory_pool(0)
        {
        }

        CL_MemoryPoolAllocator(const CL_MemoryPoolAllocator<_Type> &_src)
        : _memory_pool(_src._memory_pool)
        {
        }

        template<typename _Other>
        CL_MemoryPoolAllocator(const CL_MemoryPoolAllocator<_Other> &_src)
        : _memory_pool(_src._memory_pool)
        {
        }

        CL_MemoryPoolAllocator(CL_MemoryPool *_memory_pool)
        : _memory_pool(_memory_pool)
        {
        }

        pointer address(reference _x) const
        {
                return &_x;
        }

        const_pointer address(const_reference _x) const
        {
                return &_x;
        }

        template<typename _Other>
        pointer allocate(size_type _count, const _Other *_Hint = 0)
        {
                if (_memory_pool)
                        return (pointer) _memory_pool->alloc(_count * sizeof(value_type));
                else
                        _fallback_alloc.allocate(_count, _Hint);
        }

        void destroy(pointer _ptr, size_type _count)
        {
                if (_memory_pool)
                        _memory_pool->free(_ptr);
                else
                        _fallback_alloc.destroy(_ptr);
        }

        size_type max_size() const
        {
                return (size_type) -1;
        }

        template<typename _Other>
        struct rebind
        {
                typedef CL_MemoryPoolAllocator<_Other> other;
        };

        void construct(pointer _ptr, const _Type &_value)
        {
                if (_memory_pool)
                        new((void *) _ptr) _Type(_value);
                else
                        _fallback_alloc.construct(_ptr, _value);
        }

        void deallocate(pointer _ptr)
        {
                if (_memory_pool)
                        _ptr->_Type::~_Type();
                else
                        _fallback_alloc.destroy(_ptr);
        }

private:
        CL_MemoryPool *_memory_pool;
        std::allocator<_Type> _fallback_alloc;
};

inline void *operator new(size_t size, CL_MemoryPool *pool)
{
        if (pool)
                return pool->alloc(size);
        else
                return ::operator new(size);
}

inline void operator delete(void *data, CL_MemoryPool *pool)
{
        if (pool)
                pool->free(data);
        else
		::operator delete(data);
}

inline void *operator new[](size_t size, CL_MemoryPool *pool)
{
        if (pool)
                return pool->alloc(size);
        else
                return ::operator new[](size);
}

inline void operator delete[](void *data, CL_MemoryPool *pool)
{
        if (pool)
                pool->free(data);
        else
		::operator delete[](data);
}

#define cl_new new

template <typename Type>
void cl_delete(CL_MemoryPool *pool, Type *obj)
{
        if (obj)
                obj->~Type();
        operator delete(obj, pool);
}

template <typename Type>
void cl_delete(CL_MemoryPool *pool, Type *obj, size_t array_size)
{
        if (obj)
                for (size_t pos = 0; pos < array_size; pos++)
                        obj[pos].~Type();
#ifdef __GNUC__

        void *data = obj;
        if (pool)
                pool->free(data);
        else
		::operator delete[](data);
#else
        operator delete[](obj, pool);
#endif
}

---