fixed_allocator_eastl.h

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// EASTL/fixed_allocator.h
//
// Copyright (c) 2005, Electronic Arts. All rights reserved.
// Written and maintained by Paul Pedriana.

// This file implements the following
//     fixed_allocator
//     fixed_allocator_with_overflow


#ifndef EASTL_FIXED_ALLOCATOR_H
#define EASTL_FIXED_ALLOCATOR_H


#include <stk_util/util/config_eastl.h>
#include <stk_util/util/fixed_pool_eastl.h>
#include <stk_util/util/functional_eastl.h>
#include <stk_util/util/memory_eastl.h>
#include <stk_util/util/allocator_eastl.h>
#include <stk_util/util/type_traits_eastl.h>

#ifdef _MSC_VER
    #pragma warning(push, 0)
    #include <new>
    #pragma warning(pop)
#else
    #include <new>
#endif


namespace eastl
{

    // fixed_allocator

    class EASTL_API fixed_allocator : public fixed_pool_base
    {
    public:
        fixed_allocator(const char* /*pName*/ = EASTL_FIXED_POOL_DEFAULT_NAME)
            : fixed_pool_base(NULL)
        {
        }


        fixed_allocator(const fixed_allocator&)
            : fixed_pool_base(NULL)
        {
        }


        fixed_allocator& operator=(const fixed_allocator&)
        {
            return *this;
        }


        // init
        //
        // No init here, as the base class version is sufficient.
        //
        //void init(void* pMemory, size_t memorySize, size_t nodeSize,
        //            size_t alignment, size_t alignmentOffset = 0);


        void* allocate(size_t /*n*/, int /*flags*/ = 0)
        {
            // To consider: Verify that 'n' is what the user initialized us with.

            Link* pLink = mpHead;

            if(pLink) // If we have space...
            {
                #if EASTL_FIXED_SIZE_TRACKING_ENABLED
                    if(++mnCurrentSize > mnPeakSize)
                        mnPeakSize = mnCurrentSize;
                #endif

                mpHead = pLink->mpNext;
                return pLink;
            }
            else
            {
                // If there's no free node in the free list, just
                // allocate another from the reserved memory area

                if(mpNext != mpCapacity)
                {
                    pLink = mpNext;

                    mpNext = reinterpret_cast<Link*>(reinterpret_cast<char8_t*>(mpNext) + mnNodeSize);

                    #if EASTL_FIXED_SIZE_TRACKING_ENABLED
                        if(++mnCurrentSize > mnPeakSize)
                            mnPeakSize = mnCurrentSize;
                    #endif

                    return pLink;
                }

                // EASTL_ASSERT(false); To consider: enable this assert. However, we intentionally disable it because this isn't necessarily an assertable error.
                return NULL;
            }
        }


        void* allocate(size_t n, size_t /*alignment*/, size_t /*offset*/, int flags = 0)
        {
            return allocate(n, flags);
        }


        void deallocate(void* p, size_t)
        {
            #if EASTL_FIXED_SIZE_TRACKING_ENABLED
                --mnCurrentSize;
            #endif

            ((Link*)p)->mpNext = mpHead;
            mpHead = ((Link*)p);
        }


        using fixed_pool_base::can_allocate;


        const char* get_name() const
        {
            return EASTL_FIXED_POOL_DEFAULT_NAME;
        }


        void set_name(const char*)
        {
            // Nothing to do. We don't allocate memory.
        }

    }; // fixed_allocator

    bool operator==(const fixed_allocator& a, const fixed_allocator& b);
    bool operator!=(const fixed_allocator& a, const fixed_allocator& b);



    // fixed_allocator_with_overflow

    class EASTL_API fixed_allocator_with_overflow : public fixed_pool_base
    {
    public:
        fixed_allocator_with_overflow(const char* pName = EASTL_FIXED_POOL_DEFAULT_NAME)
            : fixed_pool_base(NULL),
              mOverflowAllocator(pName)
        {
        }


        fixed_allocator_with_overflow(const fixed_allocator_with_overflow&)
            : fixed_pool_base(NULL)
        {
        }


        fixed_allocator_with_overflow& operator=(const fixed_allocator_with_overflow& x)
        {
            #if EASTL_ALLOCATOR_COPY_ENABLED
                mOverflowAllocator = x.mOverflowAllocator;
            #else
                (void)x;
            #endif

            return *this;
        }


        void init(void* pMemory, size_t memorySize, size_t nodeSize,
                    size_t alignment, size_t alignmentOffset = 0)
        {
            fixed_pool_base::init(pMemory, memorySize, nodeSize, alignment, alignmentOffset);

            mpPoolBegin = pMemory;
            mpPoolEnd   = (void*)((uintptr_t)pMemory + memorySize);
            mnNodeSize  = (eastl_size_t)nodeSize;
        }


        void* allocate(size_t /*n*/, int /*flags*/ = 0)
        {
            // To consider: Verify that 'n' is what the user initialized us with.

            void* p;

            if(mpHead) // If we have space...
            {
                p      = mpHead;
                mpHead = mpHead->mpNext;
            }
            else
                p = mOverflowAllocator.allocate(mnNodeSize);

            #if EASTL_FIXED_SIZE_TRACKING_ENABLED
                if(p && (++mnCurrentSize > mnPeakSize))
                    mnPeakSize = mnCurrentSize;
            #endif

            return p;
        }


        void* allocate(size_t n, size_t /*alignment*/, size_t /*offset*/, int flags = 0)
        {
            return allocate(n, flags);
        }


        void deallocate(void* p, size_t)
        {
            #if EASTL_FIXED_SIZE_TRACKING_ENABLED
                --mnCurrentSize;
            #endif

            if((p >= mpPoolBegin) && (p < mpPoolEnd))
            {
                ((Link*)p)->mpNext = mpHead;
                mpHead = ((Link*)p);
            }
            else
                mOverflowAllocator.deallocate(p, (size_t)mnNodeSize);
        }


        using fixed_pool_base::can_allocate;


        const char* get_name() const
        {
            return mOverflowAllocator.get_name();
        }


        void set_name(const char* pName)
        {
            mOverflowAllocator.set_name(pName);
        }

    protected:
        EASTLAllocatorType mOverflowAllocator;  // To consider: Allow the user to define the type of this, presumably via a template parameter.
        void*              mpPoolBegin;         // To consider: We have these member variables and ideally we shouldn't need them. The problem is that
        void*              mpPoolEnd;           //              the information about the pool buffer and object size is stored in the owning container
        eastl_size_t       mnNodeSize;          //              and we can't have access to it without increasing the amount of code we need and by templating
                                                //              more code. It may turn out that simply storing data here is smaller in the end.
    }; // fixed_allocator_with_overflow         //              Granted, this class is usually used for debugging purposes, but perhaps there is an elegant solution.

    bool operator==(const fixed_allocator_with_overflow& a, const fixed_allocator_with_overflow& b);
    bool operator!=(const fixed_allocator_with_overflow& a, const fixed_allocator_with_overflow& b);






    // global operators

    inline bool operator==(const fixed_allocator&, const fixed_allocator&)
    {
        return false;
    }

    inline bool operator!=(const fixed_allocator&, const fixed_allocator&)
    {
        return false;
    }

    inline bool operator==(const fixed_allocator_with_overflow&, const fixed_allocator_with_overflow&)
    {
        return false;
    }

    inline bool operator!=(const fixed_allocator_with_overflow&, const fixed_allocator_with_overflow&)
    {
        return false;
    }


} // namespace eastl




#endif // Header include guard