kcontainerallocators.h

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#ifndef FBXFILESDK_COMPONENTS_KBASELIB_KLIB_KCONTAINERALLOCATORS_H
#define FBXFILESDK_COMPONENTS_KBASELIB_KLIB_KCONTAINERALLOCATORS_H

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

 Copyright (C) 2001 - 2009 Autodesk, Inc. and/or its licensors.
 All Rights Reserved.

 The coded instructions, statements, computer programs, and/or related material 
 (collectively the "Data") in these files contain unpublished information 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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 THE DATA IS PROVIDED "AS IS" AND WITHOUT WARRANTY.
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 OF THE DATA WILL BE UNINTERRUPTED OR ERROR FREE. 
 
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**************************************************************************************/

#include <fbxfilesdk/components/kbaselib/kbaselib_h.h>

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

#include <stdlib.h>

#include <fbxfilesdk/fbxfilesdk_nsbegin.h>

class KFBX_DLL KBaseAllocator
{
public:
    KBaseAllocator(size_t const pRecordSize)
        : mRecordSize(pRecordSize)
    {
    }

    void Reserve(size_t const pRecordCount)
    {
    }

    void* AllocateRecords(size_t const pRecordCount = 1)
    {
        return malloc(pRecordCount * mRecordSize);
    }

    void FreeMemory(void* pRecord)
    {
        free(pRecord);
    }

    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;
};

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)
        {
            delete lCurrent;
            lCurrent = lNext;
            lNext = lCurrent ? lCurrent->mNextBlock : 0;
        }
    }

    void Reserve(size_t const pRecordCount)
    {
        MemoryBlock* lMem = new 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)
    {
    }

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

        ~MemoryBlock()
        {
            free(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