MemoryPool.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
// This software owned by Onix Solutions Limited [OnixS] and is
// protected by copyright law and international copyright treaties.
//
// Access to and use of the software is governed by the terms of the applicable
// OnixS Software Services Agreement (the Agreement) and Customer end user license
// agreements granting a non-assignable, non-transferable and non-exclusive license
// to use the software for it's own data processing purposes under the terms defined
// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or
// reproduction of any part of this source code or associated reference material
// to any other location for further reproduction or redistribution, and any
// amendments to this copyright notice, are expressly prohibited.
//
// Any reproduction or redistribution for sale or hiring of the Software not in
// accordance with the terms of the Agreement is a violation of copyright law.
//
 
#pragma once
 
#if defined(ONIXS_CMEMDH_ENABLE_TRACING)
#  include <ostream>
#endif
 
#include <OnixS/CME/MDH/Bootstrap.h>
 
ONIXS_CMEMDH_NAMESPACE_BEGIN

class ONIXS_CMEMDH_EXPORTED MemoryPool
{
public:
    virtual void release() = 0;

    virtual void* allocate(size_t) = 0;

    virtual void deallocate(void*) = 0;
 
#if defined(ONIXS_CMEMDH_ENABLE_TRACING)
    virtual void trace(std::ostream&) = 0;
#endif
 
protected:
    MemoryPool() {}

    virtual ~MemoryPool() {}
 
private:
    // Copies are disallowed.
    MemoryPool(const MemoryPool&) {}
 
    // Assignment is disallowed.
    MemoryPool& operator=(const MemoryPool&)
    {
        return *this;
    }
};
 
// Implements STL allocator over MemoryPool.
template <class Object>
class MemoryPoolAllocator
{
public:
    typedef Object value_type;
    typedef Object* pointer;
    typedef const Object* const_pointer;
 
    typedef Object& reference;
    typedef const Object& const_reference;
 
    typedef std::size_t size_type;
    typedef std::ptrdiff_t difference_type;
 
    template <class Other>
    struct rebind
    {
        typedef MemoryPoolAllocator<Other> other;
    };
 
    MemoryPoolAllocator()
        : pool_(ONIXS_CMEMDH_NULLPTR)
    {
    }
 
    MemoryPoolAllocator(MemoryPool& memoryPool)
        : pool_(&memoryPool)
    {
    }
 
    MemoryPoolAllocator(const MemoryPoolAllocator& other)
        : pool_(other.pool_)
    {
    }
 
    template <class Other>
    MemoryPoolAllocator(const MemoryPoolAllocator<Other>& other)
        : pool_(&other.memoryPool())
    {
    }
 
    ~MemoryPoolAllocator() {}
 
    MemoryPool& memoryPool() const
    {
        return *pool_;
    }
 
    pointer address(reference obj) const
    {
        return &obj;
    }
 
    const_pointer address(const_reference x) const
    {
        return &x;
    }
 
    pointer allocate(size_type qty)
    {
        assert(ONIXS_CMEMDH_NULLPTR != pool_);
 
        return static_cast<pointer>(pool_->allocate(qty * sizeof(value_type)));
    }
 
    void deallocate(pointer block, size_type)
    {
        assert(ONIXS_CMEMDH_NULLPTR != pool_);
 
        pool_->deallocate(block);
    }
 
    void construct(pointer block, const value_type& obj)
    {
        new (block) value_type(obj);
    }
 
    void destroy(pointer obj)
    {
        obj->~value_type();
        (void) obj;
    }
 
    size_type max_size() const
    {
        return static_cast<size_type>(-1) / sizeof(value_type);
    }
 
    MemoryPoolAllocator& operator=(const MemoryPoolAllocator& other)
    {
        pool_ = other.pool_;
 
        return *this;
    }
 
    template <class Other>
    MemoryPoolAllocator& operator=(const MemoryPoolAllocator<Other>& other)
    {
        pool_ = &other.memoryPool();
 
        return *this;
    }
 
private:
    MemoryPool* pool_;
};
 
template <class Object, class OtherObject>
inline bool operator==(const MemoryPoolAllocator<Object>& left, const MemoryPoolAllocator<OtherObject>& right)
{
    return (&left.memoryPool() == &right.memoryPool());
}
 
template <class Object, class OtherObject>
inline bool operator!=(const MemoryPoolAllocator<Object>& left, const MemoryPoolAllocator<OtherObject>& right)
{
    return (&left.memoryPool() != &right.memoryPool());
}

ONIXS_CMEMDH_EXPORTED
MemoryPool* makeMemoryPool(size_t, size_t, size_t, size_t);
 
ONIXS_CMEMDH_NAMESPACE_END