/*!  \file kcontainerallocators.h

 */



#ifndef FBXFILESDK_COMPONENTS_KBASELIB_KLIB_KCONTAINERALLOCATORS_H

#define FBXFILESDK_COMPONENTS_KBASELIB_KLIB_KCONTAINERALLOCATORS_H



/**************************************************************************************



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 All Rights Reserved.



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 (collectively the "Data") in these files contain unpublished information 

 proprietary to Autodesk, Inc. and/or its licensors, which is protected by 

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 treaties. 

 

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 part, without the prior written consent of Autodesk, Inc. ("Autodesk").



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 WARRANTY OF ANY KIND WITH RESPECT TO THE DATA, EXPRESS, IMPLIED OR ARISING

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**************************************************************************************/

#include <fbxfilesdk/fbxfilesdk_def.h>



#include <fbxfilesdk/components/kbaselib/klib/kdebug.h>



#include <fbxfilesdk/fbxfilesdk_nsbegin.h>



/**An allocator class for use as a template parameter to one of the

  *container class (KMap, KSet2, KDynamicArray...) must implement these.

  */



class KFBX_DLL KBaseAllocator

{

public:

    /** The class constructor.  

      * \param pRecordSize the size of one record held by the container. 

      * \remarks The parameter pRecordSize is not necessarily the same 

      *  size as of the value type, since the

      *  container may wrap the value into a private class.

      */

    KBaseAllocator(size_t const pRecordSize)

        : mRecordSize(pRecordSize)

    {

    }



    /** This tells the allocator that we are about to call AllocateRecords

      * one or many times to allocate pRecordCount records. 

      * \param pRecordCount

      * \remarks This gives the allocator a chance to do whatever it deems necessary

      * to optimize subsequent allocations, for example, by preallocating a

      * sufficiently large pool of memory.

      */

    void Reserve(size_t const pRecordCount)

    {

        // By default, ignore all preallocating requests.

    }



    /** Returns a pointer to a uninitialized continuous block of memory

      * able to hold pRecordCount * pRecordSize  bytes.  

      * \param pRecordCount

      * \remarks pRecordSize was defined in the Constructor description, above.

      */

    void* AllocateRecords(size_t const pRecordCount = 1)

    {

        return FbxSdkMalloc(pRecordCount * mRecordSize);

    }



    /** Frees a block of memory returned by AllocateRecords. 

      * \param pRecord

      */

    void FreeMemory(void* pRecord)

    {

        FbxSdkFree(pRecord);

    }



    /** \return the size of each record allocated. 

      */

    size_t GetRecordSize() const

    {

        return mRecordSize;

    }



    // Use default copy / assignment

    /*    operator=()

        *        The allocator must have appropriate copy semantics; does not need to

        *        copy its allocated blocks, but it should adjust its record size.

        */



private:

    size_t mRecordSize;

};



/**

  *This allocator only frees the allocated memory when it is deleted.

  *This is a good allocator for building dictionaries, where we only

  *add things to a container, but never remove them.

  */

class KHungryAllocator

{

public:

    KHungryAllocator(size_t pRecordSize)

        : mRecordSize(pRecordSize)

        , mData(NULL)

        , mRecordPoolSize(0)

    {

    }



    KHungryAllocator(const KHungryAllocator& pOther)

        : mRecordSize(pOther.mRecordSize)

        , mData(0)

        , mRecordPoolSize(pOther.mRecordPoolSize)

    {

    }



	~KHungryAllocator()

	{

		MemoryBlock* lCurrent = mData;

		MemoryBlock* lNext = lCurrent ? lCurrent->mNextBlock : 0;

		while (lCurrent)

		{

			FbxSdkDelete(lCurrent);

			lCurrent = lNext;

			lNext = lCurrent ? lCurrent->mNextBlock : 0;

		}

	}



    void Reserve(size_t const pRecordCount)

    {

        MemoryBlock* lMem = FbxSdkNew< MemoryBlock >(pRecordCount * mRecordSize);

        lMem->mNextBlock = mData;

        mData = lMem;

        mRecordPoolSize += pRecordCount;

    }



    void* AllocateRecords(size_t const pRecordCount = 1)

    {

        MemoryBlock* lBlock = mData;

        void* lRecord = NULL;



        while ((lBlock != NULL) &&

            ((lRecord = lBlock->GetChunk(pRecordCount * mRecordSize)) == NULL))

        {

            lBlock = lBlock->mNextBlock;

        }



        if (lRecord == NULL)

        {

            size_t lNumRecordToAllocate = mRecordPoolSize / 8 == 0 ? 2 : mRecordPoolSize / 8;

            if (lNumRecordToAllocate < pRecordCount)

            {

                lNumRecordToAllocate = pRecordCount;

            }

            Reserve(lNumRecordToAllocate);

            lRecord = AllocateRecords(pRecordCount);

        }



        return lRecord;

    }



    void FreeMemory(void* pRecord)

    {

        // "Hungry": release memory only when the allocator is destroyed.

    }



    size_t GetRecordSize() const

    {

        return mRecordSize;

    }



    KHungryAllocator& operator=(const KHungryAllocator& pOther)

    {

        if( this != &pOther )

        {

            // The next call to AllocateRecords() may skip over currently reserved

            // records if the size changes drastically, but otherwise GetChunk()

            // is size-oblivious.

            if( mRecordSize < pOther.mRecordSize )

            {

                mRecordPoolSize = 0;

            }



            mRecordSize = pOther.mRecordSize;

        }



        return(*this);

    }



private:

    class MemoryBlock

    {

    public:

        MemoryBlock(size_t pSize)

            : mNextBlock(NULL)

            , mData(NULL)

            , mFreeData(NULL)

            , mEnd(NULL)

        {

            mData = FbxSdkMalloc(pSize);

            mFreeData = mData;

            mEnd = reinterpret_cast<char*>(mData) + pSize;

        };



        ~MemoryBlock()

        {

            FbxSdkFree(mData);

        }



        void* GetChunk(size_t const pSize)

        {

            if (reinterpret_cast<char*>(mFreeData) + pSize < mEnd)

            {

                void* lChunk = mFreeData;

                mFreeData = reinterpret_cast<char*>(mFreeData) + pSize;

                return lChunk;

            }



            return NULL;

        }



        MemoryBlock* mNextBlock;

        void* mData;

        void* mFreeData;

        void* mEnd;

    };



	size_t mRecordSize;

    MemoryBlock* mData;

    size_t mRecordPoolSize;

};



#include <fbxfilesdk/fbxfilesdk_nsend.h>



#endif // FBXFILESDK_COMPONENTS_KBASELIB_KLIB_KCONTAINERALLOCATORS_H



