/* ------------------------------------------------------------------
 * Copyright (C) 1998-2009 PacketVideo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 * -------------------------------------------------------------------
 */
#include "oscl_mem_mempool.h"
#include <utils/Log.h>


/**
 *  OsclMemPoolFixedChunkAllocator section
 **/

OSCL_EXPORT_REF OsclMemPoolFixedChunkAllocator::OsclMemPoolFixedChunkAllocator(const uint32 numchunk, const uint32 chunksize, Oscl_DefAlloc* gen_alloc) :
        iNumChunk(1), iChunkSize(0), iChunkSizeMemAligned(0),
        iMemPoolAllocator(gen_alloc), iMemPool(NULL),
        iCheckNextAvailableFreeChunk(false), iObserver(NULL),
        iNextAvailableContextData(NULL),
        iRefCount(1),
        iEnableNullPtrReturn(false)
{
    iNumChunk = numchunk;
    iChunkSize = chunksize;

    if (iNumChunk == 0)
    {
        iNumChunk = 1;
    }

    if (iChunkSize > 0)
    {
        createmempool();
    }
}

OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::enablenullpointerreturn()
{
    iEnableNullPtrReturn = true;
}

OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::addRef()
{
    // Just increment the ref count
    ++iRefCount;
}

OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::removeRef()
{
    // Decrement the ref count
    --iRefCount;

    // If ref count reaches 0 then destroy this object automatically
    if (iRefCount <= 0)
    {
        OSCL_DELETE(this);
    }
}


OSCL_EXPORT_REF OsclMemPoolFixedChunkAllocator::~OsclMemPoolFixedChunkAllocator()
{
    // Decrement the ref count
    --iRefCount;

    // If ref count reaches 0 then destroy this object
    if (iRefCount <= 0)
    {
        destroymempool();
    }
}


OSCL_EXPORT_REF OsclAny* OsclMemPoolFixedChunkAllocator::allocate(const uint32 n)
{
    // Create the memory pool if it hasn't been created yet.
    // Use the allocation size, n, as the chunk size for memory pool
    if (iChunkSize == 0)
    {
        iChunkSize = n;
        createmempool();
    }
    else if (n > iChunkSize)
    {
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(NULL);    This statement was removed to avoid compiler warning for Unreachable Code

    }

    if (iFreeMemChunkList.empty())
    {
        // No free chunk is available
        if (iEnableNullPtrReturn)
        {
            return NULL;
        }
        else
        {
            OSCL_LEAVE(OsclErrNoResources);
        }
    }

    // Return the next available chunk from the pool
    OsclAny* freechunk = iFreeMemChunkList.back();
    // Remove the chunk from the free list
    iFreeMemChunkList.pop_back();
    addRef();
    return freechunk;
}


OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::deallocate(OsclAny* p)
{
    if (iMemPool == NULL)
    {
        // Memory pool hasn't been allocated yet so error
        OSCL_LEAVE(OsclErrNotReady);
    }

    uint8* ptmp = (uint8*)p;
    uint8* mptmp = (uint8*)iMemPool;

    if ((ptmp < mptmp) || ptmp >= (mptmp + iNumChunk*iChunkSizeMemAligned))
    {
        // Returned memory is not part of this memory pool
        OSCL_LEAVE(OsclErrArgument);
    }

    if (((ptmp - mptmp) % iChunkSizeMemAligned) != 0)
    {
        // Returned memory is not aligned to the chunk.
        OSCL_LEAVE(OsclErrArgument);
    }

    // Put the returned chunk in the free pool
    iFreeMemChunkList.push_back(p);

    // Notify the observer about free chunk available if waiting for such callback
    if (iCheckNextAvailableFreeChunk)
    {
        iCheckNextAvailableFreeChunk = false;
        if (iObserver)
        {
            iObserver->freechunkavailable(iNextAvailableContextData);
        }
    }
    else if (iObserver && iCheckNextAvailableFreeChunk)
    {
        LOGW("We may have lost some free chunk %p available notification for memory pool %p with chunk size %d", ptmp, mptmp, iChunkSizeMemAligned);
    }

    // Decrement the refcount since deallocating succeeded
    removeRef();
}


OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::notifyfreechunkavailable(OsclMemPoolFixedChunkAllocatorObserver& obs, OsclAny* aContextData)
{
    iCheckNextAvailableFreeChunk = true;
    iObserver = &obs;
    iNextAvailableContextData = aContextData;
}

OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::CancelFreeChunkAvailableCallback()
{
    iCheckNextAvailableFreeChunk = false;
    iObserver = NULL;
    iNextAvailableContextData = NULL;
}

OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::createmempool()
{
    if (iChunkSize == 0 || iNumChunk == 0)
    {
        OSCL_LEAVE(OsclErrArgument);
    }

    // Create one block of memory for the memory pool
    iChunkSizeMemAligned = oscl_mem_aligned_size(iChunkSize);
    int32 leavecode = 0;
    if (iMemPoolAllocator)
    {
        OSCL_TRY(leavecode, iMemPool = iMemPoolAllocator->ALLOCATE(iNumChunk * iChunkSizeMemAligned));
    }
    else
    {
        iMemPool = OSCL_MALLOC(iNumChunk * iChunkSizeMemAligned);
    }

    if (leavecode || iMemPool == NULL)
    {
        OSCL_LEAVE(OsclErrNoMemory);
    }

#if OSCL_MEM_FILL_WITH_PATTERN
    oscl_memset(iMemPool, 0x55, iNumChunk*iChunkSizeMemAligned);
#endif

    // Set up the free mem chunk list vector
    iFreeMemChunkList.reserve(iNumChunk);
    uint8* chunkptr = (uint8*)iMemPool;

    for (uint32 i = 0; i < iNumChunk; ++i)
    {
        iFreeMemChunkList.push_back((OsclAny*)chunkptr);
        chunkptr += iChunkSizeMemAligned;
    }
}


OSCL_EXPORT_REF void OsclMemPoolFixedChunkAllocator::destroymempool()
{
    // If ref count reaches 0 then destroy this object
    if (iRefCount <= 0)
    {
#if OSCL_MEM_CHECK_ALL_MEMPOOL_CHUNKS_ARE_RETURNED
        // Assert if all of the chunks were not returned
        OSCL_ASSERT(iFreeMemChunkList.size() == iNumChunk);
#endif

        iFreeMemChunkList.clear();

        if (iMemPool)
        {
            if (iMemPoolAllocator)
            {
                iMemPoolAllocator->deallocate(iMemPool);
            }
            else
            {
                OSCL_FREE(iMemPool);
            }

            iMemPool = NULL;
        }
    }
}


/**
 *  OsclMemPoolResizableAllocator section
 **/

#define OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER 10
#define OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN 0x55
#define OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN 0xAA
#define OSCLMEMPOOLRESIZABLEALLOCATOR_MIN_BUFFERSIZE 8

OSCL_EXPORT_REF OsclMemPoolResizableAllocator::OsclMemPoolResizableAllocator(uint32 aMemPoolBufferSize, uint32 aMemPoolBufferNumLimit, uint32 aExpectedNumBlocksPerBuffer, Oscl_DefAlloc* gen_alloc) :
        iMemPoolBufferSize(aMemPoolBufferSize),
        iMemPoolBufferNumLimit(aMemPoolBufferNumLimit),
        iExpectedNumBlocksPerBuffer(aExpectedNumBlocksPerBuffer),
        iMemPoolBufferAllocator(gen_alloc),
        iCheckNextAvailable(false),
        iRequestedNextAvailableSize(0),
        iNextAvailableContextData(NULL),
        iObserver(NULL),
        iCheckFreeMemoryAvailable(false),
        iRequestedAvailableFreeMemSize(0),
        iFreeMemContextData(NULL),
        iFreeMemPoolObserver(NULL),
        iRefCount(1),
        iEnableNullPtrReturn(false)
{
    OSCL_ASSERT(aMemPoolBufferSize > OSCLMEMPOOLRESIZABLEALLOCATOR_MIN_BUFFERSIZE);

    iMaxNewMemPoolBufferSz = 0;
    // Calculate and save the mem aligned size of buffer and block info header structures
    iBufferInfoAlignedSize = oscl_mem_aligned_size(sizeof(MemPoolBufferInfo));
    iBlockInfoAlignedSize = oscl_mem_aligned_size(sizeof(MemPoolBlockInfo));

    // Pre-allocate memory for vector
    if (iMemPoolBufferNumLimit > 0)
    {
        iMemPoolBufferList.reserve(iMemPoolBufferNumLimit);
    }
    else
    {
        iMemPoolBufferList.reserve(2);
    }

    // Determine the size of memory pool buffer and create one
    uint32 buffersize = oscl_mem_aligned_size(iMemPoolBufferSize) + iBufferInfoAlignedSize;
    if (iExpectedNumBlocksPerBuffer > 0)
    {
        buffersize += (iExpectedNumBlocksPerBuffer * iBlockInfoAlignedSize);
    }
    else
    {
        buffersize += (OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER * iBlockInfoAlignedSize);
    }

    addnewmempoolbuffer(buffersize);
}

OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::enablenullpointerreturn()
{
    iEnableNullPtrReturn = true;
}

OSCL_EXPORT_REF OsclAny* OsclMemPoolResizableAllocator::allocate(const uint32 aNumBytes)
{
    MemPoolBlockInfo* freeblock = NULL;
    uint32 alignednumbytes = oscl_mem_aligned_size(aNumBytes);

    if (aNumBytes == 0)
    {
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(NULL);    This statement was removed to avoid compiler warning for Unreachable Code
    }

    // Find a free block that would accomodate the requested size with a block info header
    freeblock = findfreeblock(alignednumbytes + iBlockInfoAlignedSize);
    if (freeblock == NULL)
    {
        //We could not find the new buffer, the only way we can allocate the chunk is by allocating newmempool buffer
        //Validate is size is less than the regrow size.
        if (iMemPoolBufferNumLimit > 0 && iMaxNewMemPoolBufferSz > 0 && iMaxNewMemPoolBufferSz < alignednumbytes)
        {
            //cannot create the new buffer
            if (iEnableNullPtrReturn)
            {
                return NULL;
            }
            else
            {
                // Leave with resource limitation
                OSCL_LEAVE(OsclErrNoResources);
            }

        }
        // Check if the requested size is bigger than the specified buffer size
        if (alignednumbytes > iMemPoolBufferSize)
        {
            // Would need to create a new buffer to accomodate this request

            // Check if another buffer can be created
            if (iMemPoolBufferNumLimit > 0 && iMemPoolBufferList.size() >= iMemPoolBufferNumLimit)
            {
                // Check if there is a memory pool buffer that has no outstanding buffers
                // If present then remove it so a new one can be added
                bool emptybufferfound = false;
                for (uint32 j = 0; j < iMemPoolBufferList.size(); ++j)
                {
                    if (iMemPoolBufferList[j]->iNumOutstanding == 0)
                    {
                        // Free the memory
                        if (iMemPoolBufferAllocator)
                        {
                            iMemPoolBufferAllocator->deallocate((OsclAny*)iMemPoolBufferList[j]);
                        }
                        else
                        {
                            OSCL_FREE((OsclAny*)iMemPoolBufferList[j]);
                        }

                        // Remove the mempool buffer from the list
                        iMemPoolBufferList.erase(iMemPoolBufferList.begin() + j);
                        emptybufferfound = true;
                        break;
                    }
                }

                // Need to leave and return if empty buffer not found
                if (!emptybufferfound)
                {
                    if (iEnableNullPtrReturn)
                    {
                        return NULL;
                    }
                    else
                    {
                        // Leave with resource limitation
                        OSCL_LEAVE(OsclErrNoResources);
                    }
                }

                // Continue on to create a new buffer
                OSCL_ASSERT(iMemPoolBufferList.size() < iMemPoolBufferNumLimit);
            }

            // Determine the size of memory pool buffer and create one
            uint32 buffersize = alignednumbytes + iBufferInfoAlignedSize;
            if (iExpectedNumBlocksPerBuffer > 0)
            {
                buffersize += (iExpectedNumBlocksPerBuffer * iBlockInfoAlignedSize);
            }
            else
            {
                buffersize += (OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER * iBlockInfoAlignedSize);
            }

            MemPoolBufferInfo* newbuffer = addnewmempoolbuffer(buffersize);
            OSCL_ASSERT(newbuffer != NULL);
            OSCL_ASSERT(newbuffer->iNextFreeBlock != NULL);
            freeblock = (MemPoolBlockInfo*)(newbuffer->iNextFreeBlock);
            OSCL_ASSERT(freeblock != NULL);
            OSCL_ASSERT(freeblock->iBlockSize >= alignednumbytes);
        }
        else
        {
            // Check if another buffer can be created
            if (iMemPoolBufferNumLimit > 0 && iMemPoolBufferList.size() >= iMemPoolBufferNumLimit)
            {
                if (iEnableNullPtrReturn)
                {
                    return NULL;
                }
                else
                {
                    // Leave with resource limitation
                    OSCL_LEAVE(OsclErrNoResources);
                }
            }

            // Determine the size of memory pool buffer and create one
            uint32 buffersize = oscl_mem_aligned_size(iMemPoolBufferSize) + iBufferInfoAlignedSize;
            if (iExpectedNumBlocksPerBuffer > 0)
            {
                buffersize += (iExpectedNumBlocksPerBuffer * iBlockInfoAlignedSize);
            }
            else
            {
                buffersize += (OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER * iBlockInfoAlignedSize);
            }

            MemPoolBufferInfo* newbuffer = addnewmempoolbuffer(buffersize);
            OSCL_ASSERT(newbuffer != NULL);
            OSCL_ASSERT(newbuffer->iNextFreeBlock != NULL);
            freeblock = (MemPoolBlockInfo*)(newbuffer->iNextFreeBlock);
            OSCL_ASSERT(freeblock != NULL);
            OSCL_ASSERT(freeblock->iBlockSize >= alignednumbytes);
        }

    }

    // Use the free block and return the buffer pointer
    OsclAny* bufptr = allocateblock(*freeblock, alignednumbytes);
    if (bufptr)
    {
        addRef();
        ++(freeblock->iParentBuffer->iNumOutstanding);
    }
    return bufptr;
}


OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::deallocate(OsclAny* aPtr)
{
    // Check that the returned pointer is from the memory pool
    if (validateblock(aPtr) == false)
    {
        OSCL_LEAVE(OsclErrArgument);
    }

    // Retrieve the block info header and validate the info
    uint8* byteptr = (uint8*)aPtr;
    MemPoolBlockInfo* retblock = (MemPoolBlockInfo*)(byteptr - iBlockInfoAlignedSize);
    OSCL_ASSERT(retblock != NULL);
    OSCL_ASSERT(retblock->iBlockPreFence == OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN);
    OSCL_ASSERT(retblock->iBlockPostFence == OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN);

    // Return the block to the memory pool buffer
    deallocateblock(*retblock);
    --(retblock->iParentBuffer->iNumOutstanding);

    // Check if user needs to be notified when block becomes available
    if (iCheckNextAvailable)
    {
        // Check if user is waiting for certain size
        if (iRequestedNextAvailableSize == 0)
        {
            // No so just make the callback
            iCheckNextAvailable = false;
            if (iObserver)
            {
                iObserver->freeblockavailable(iNextAvailableContextData);
            }
        }
        else
        {
            // Check if the requested size is available now
            if (findfreeblock(iRequestedNextAvailableSize + iBlockInfoAlignedSize) != NULL)
            {
                iCheckNextAvailable = false;
                if (iObserver)
                {
                    iObserver->freeblockavailable(iNextAvailableContextData);
                }
            }
            else if (iRequestedNextAvailableSize > iMemPoolBufferSize)
            {
                // The requested size is bigger than the set buffer size

                // Check if there is space to grow the buffer,
                if (iMemPoolBufferNumLimit == 0 || iMemPoolBufferList.size() < iMemPoolBufferNumLimit)
                {
                    // Available
                    iCheckNextAvailable = false;
                    if (iObserver)
                    {
                        iObserver->freeblockavailable(iNextAvailableContextData);
                    }
                }
                else
                {
                    // Not available so see if there is a buffer with
                    // no outstanding buffers which can be destroyed
                    // in the next allocate() call.
                    bool emptybufferfound = false;
                    for (uint32 j = 0; j < iMemPoolBufferList.size(); ++j)
                    {
                        if (iMemPoolBufferList[j]->iNumOutstanding == 0)
                        {
                            emptybufferfound = true;
                            break;
                        }
                    }

                    if (emptybufferfound)
                    {
                        iCheckNextAvailable = false;
                        if (iObserver)
                        {
                            iObserver->freeblockavailable(iNextAvailableContextData);
                        }
                    }
                }
            }
        }
    }
    if (iCheckFreeMemoryAvailable)
    {
        if (iRequestedAvailableFreeMemSize == 0)
        {
            // No so just make the callback
            iCheckFreeMemoryAvailable = false;
            if (iFreeMemPoolObserver)
            {
                iFreeMemPoolObserver->freememoryavailable(iFreeMemContextData);
            }
        }
        else
        {
            // Check if the requested size is available now
            if (getAvailableSize() >= iRequestedAvailableFreeMemSize)
            {
                iCheckFreeMemoryAvailable = false;
                if (iFreeMemPoolObserver)
                {
                    iFreeMemPoolObserver->freememoryavailable(iFreeMemContextData);
                }
            }
        }
    }

    // Decrement the refcount since deallocating succeeded
    removeRef();
}


OSCL_EXPORT_REF bool OsclMemPoolResizableAllocator::trim(OsclAny* aPtr, uint32 aBytesToFree)
{
    // Amount to free has to be aligned
    uint32 alignedbytestofree = oscl_mem_aligned_size(aBytesToFree);
    if (alignedbytestofree > aBytesToFree)
    {
        // Not aligned so decrease amount to free by one alignment size
        alignedbytestofree -= 8;
    }
    OSCL_ASSERT(alignedbytestofree <= aBytesToFree);

    // Check that the returned pointer is from the memory pool
    if (validateblock(aPtr) == false)
    {
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(false);   This statement was removed to avoid compiler warning for Unreachable Code
    }

    // Retrieve the block info header and validate the info
    uint8* byteptr = (uint8*)aPtr;
    MemPoolBlockInfo* resizeblock = (MemPoolBlockInfo*)(byteptr - iBlockInfoAlignedSize);
    OSCL_ASSERT(resizeblock != NULL);
    OSCL_ASSERT(resizeblock->iBlockPreFence == OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN);
    OSCL_ASSERT(resizeblock->iBlockPostFence == OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN);

    if ((resizeblock->iBlockSize - iBlockInfoAlignedSize) < alignedbytestofree)
    {
        // The bytes to free in the resize is bigger than the original buffer size
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(false);   This statement was removed to avoid compiler warning for Unreachable Code
    }

    if (alignedbytestofree < (iBlockInfoAlignedSize + OSCLMEMPOOLRESIZABLEALLOCATOR_MIN_BUFFERSIZE))
    {
        // The resizing cannot be done since the amount to free doesn't have
        // enough space to put in a block info header plus the minimum buffer for the new free block
        // So don't do anything and return
        return false;
    }

    // Create and fill in a block info header for the memory being freed back to memory pool
    MemPoolBlockInfo* freeblock = (MemPoolBlockInfo*)((uint8*)resizeblock + resizeblock->iBlockSize - alignedbytestofree);
    freeblock->iBlockPreFence = OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN;
    freeblock->iNextFreeBlock = NULL;
    freeblock->iPrevFreeBlock = NULL;
    freeblock->iBlockSize = alignedbytestofree;
    freeblock->iBlockBuffer = (uint8*)freeblock + iBlockInfoAlignedSize;
    freeblock->iParentBuffer = resizeblock->iParentBuffer;
    freeblock->iBlockPostFence = OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN;

    // Return the free block to the memory pool buffer
    deallocateblock(*freeblock);

    // Adjust the block info for the block being resized
    resizeblock->iBlockSize -= alignedbytestofree;
    return true;
}


OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::notifyfreeblockavailable(OsclMemPoolResizableAllocatorObserver& aObserver, uint32 aRequestedSize, OsclAny* aContextData)
{
    // Save the parameters for the next deallocate() call
    iCheckNextAvailable = true;
    iObserver = &aObserver;
    iRequestedNextAvailableSize = oscl_mem_aligned_size(aRequestedSize);
    iNextAvailableContextData = aContextData;
}

OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::CancelFreeChunkAvailableCallback()
{
    iCheckNextAvailable = false;
    iObserver = NULL;
    iRequestedNextAvailableSize = 0;
    iNextAvailableContextData = NULL;
}

OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::notifyfreememoryavailable(OsclMemPoolResizableAllocatorMemoryObserver& aObserver, uint32 aRequestedSize, OsclAny* aContextData)
{
    // Save the parameters for the next deallocate() call
    iCheckFreeMemoryAvailable = true;
    iFreeMemPoolObserver = &aObserver;
    iRequestedAvailableFreeMemSize = oscl_mem_aligned_size(aRequestedSize);
    iFreeMemContextData = aContextData;
}

OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::CancelFreeMemoryAvailableCallback()
{
    iCheckFreeMemoryAvailable = false;
    iFreeMemPoolObserver = NULL;
    iRequestedAvailableFreeMemSize = 0;
    iFreeMemContextData = NULL;
}

OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::addRef()
{
    // Just increment the ref count
    ++iRefCount;
}


OSCL_EXPORT_REF void OsclMemPoolResizableAllocator::removeRef()
{
    // Decrement the ref count
    --iRefCount;

    // If ref count reaches 0 then destroy this object automatically
    if (iRefCount <= 0)
    {
        OSCL_DELETE(this);
    }
}


OSCL_EXPORT_REF OsclMemPoolResizableAllocator::~OsclMemPoolResizableAllocator()
{
    destroyallmempoolbuffers();
}


OsclMemPoolResizableAllocator::MemPoolBufferInfo* OsclMemPoolResizableAllocator::addnewmempoolbuffer(uint32 aBufferAlignedSize)
{
    OSCL_ASSERT(aBufferAlignedSize > 0);
    OSCL_ASSERT(aBufferAlignedSize == oscl_mem_aligned_size(aBufferAlignedSize));

    // Allocate memory for one buffer
    uint8* newbuffer = NULL;
    if (iMemPoolBufferAllocator)
    {
        // Use the outside allocator
        newbuffer = (uint8*)iMemPoolBufferAllocator->ALLOCATE(aBufferAlignedSize);
    }
    else
    {
        // Allocate directly from heap
        newbuffer = (uint8*)OSCL_MALLOC(aBufferAlignedSize);
    }

    if (newbuffer == NULL)
    {
        OSCL_LEAVE(OsclErrNoMemory);
        // OSCL_UNUSED_RETURN(NULL);    This statement was removed to avoid compiler warning for Unreachable Code
    }

#if OSCL_MEM_FILL_WITH_PATTERN
    oscl_memset(newbuffer, 0x55, aBufferAlignedSize);
#endif

    // Fill in the buffer info header
    MemPoolBufferInfo* newbufferinfo = (MemPoolBufferInfo*)newbuffer;
    newbufferinfo->iBufferPreFence = OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN;
    newbufferinfo->iStartAddr = (OsclAny*)(newbuffer + iBufferInfoAlignedSize);
    newbufferinfo->iEndAddr = (OsclAny*)(newbuffer + aBufferAlignedSize - 1);
    newbufferinfo->iBufferSize = aBufferAlignedSize;
    newbufferinfo->iNumOutstanding = 0;
    newbufferinfo->iNextFreeBlock = (MemPoolBlockInfo*)(newbufferinfo->iStartAddr);
    newbufferinfo->iAllocatedSz = 0;
    newbufferinfo->iBufferPostFence = OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN;

    // Put in one free block in the new buffer
    MemPoolBlockInfo* freeblockinfo = (MemPoolBlockInfo*)(newbufferinfo->iStartAddr);
    freeblockinfo->iBlockPreFence = OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN;
    freeblockinfo->iNextFreeBlock = NULL;
    freeblockinfo->iPrevFreeBlock = NULL;
    freeblockinfo->iBlockSize = aBufferAlignedSize - iBufferInfoAlignedSize;
    freeblockinfo->iBlockBuffer = (uint8*)freeblockinfo + iBlockInfoAlignedSize;
    freeblockinfo->iParentBuffer = newbufferinfo;
    freeblockinfo->iBlockPostFence = OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN;

    // Add the new buffer to the list
    iMemPoolBufferList.push_front(newbufferinfo);

    return newbufferinfo;
}


void OsclMemPoolResizableAllocator::destroyallmempoolbuffers()
{
    while (iMemPoolBufferList.empty() == false)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[0];
        // Check the buffer
        OSCL_ASSERT(bufferinfo != NULL);
        OSCL_ASSERT(bufferinfo->iBufferPreFence == OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN);
        OSCL_ASSERT(bufferinfo->iBufferPostFence == OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN);
        OSCL_ASSERT(bufferinfo->iNumOutstanding == 0);

        // Free the memory
        if (iMemPoolBufferAllocator)
        {
            iMemPoolBufferAllocator->deallocate((OsclAny*)bufferinfo);
        }
        else
        {
            OSCL_FREE((OsclAny*)bufferinfo);
        }

        iMemPoolBufferList.erase(iMemPoolBufferList.begin());
    }
}


OsclMemPoolResizableAllocator::MemPoolBlockInfo* OsclMemPoolResizableAllocator::findfreeblock(uint32 aBlockAlignedSize)
{
    OSCL_ASSERT(aBlockAlignedSize > 0);
    OSCL_ASSERT(aBlockAlignedSize == oscl_mem_aligned_size(aBlockAlignedSize));

    // Go through each mempool buffer and return the first free block that
    // is bigger than the specified size

    if (aBlockAlignedSize == 0)
    {
        // Request should be non-zero
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(NULL);    This statement was removed to avoid compiler warning for Unreachable Code
    }

    for (uint32 i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
        MemPoolBlockInfo* blockinfo = bufferinfo->iNextFreeBlock;
        while (blockinfo != NULL)
        {
            if ((blockinfo->iBlockSize/* - iBlockInfoAlignedSize*/) >= aBlockAlignedSize)
            {
                // This free block fits the request
                return blockinfo;
            }

            // Go to the next free block
            blockinfo = blockinfo->iNextFreeBlock;
        }
    }

    return NULL;
}


OsclAny* OsclMemPoolResizableAllocator::allocateblock(MemPoolBlockInfo& aBlockPtr, uint32 aNumAlignedBytes)
{
    OSCL_ASSERT(aNumAlignedBytes > 0);
    OSCL_ASSERT(aNumAlignedBytes == oscl_mem_aligned_size(aNumAlignedBytes));

    if (aNumAlignedBytes == 0)
    {
        OSCL_LEAVE(OsclErrArgument);
        // OSCL_UNUSED_RETURN(NULL);    This statement was removed to avoid compiler warning for Unreachable Code
    }

    // Remove the free block from the double linked list
    if (aBlockPtr.iPrevFreeBlock == NULL && aBlockPtr.iNextFreeBlock != NULL)
    {
        // Removing from the beginning of the free list
        aBlockPtr.iNextFreeBlock->iPrevFreeBlock = NULL;
        aBlockPtr.iParentBuffer->iNextFreeBlock = aBlockPtr.iNextFreeBlock;
    }
    else if (aBlockPtr.iPrevFreeBlock != NULL && aBlockPtr.iNextFreeBlock == NULL)
    {
        // Removing from the end of the free list
        aBlockPtr.iPrevFreeBlock->iNextFreeBlock = NULL;
    }
    else if (aBlockPtr.iPrevFreeBlock == NULL && aBlockPtr.iNextFreeBlock == NULL)
    {
        // Free list becomes empty so update the parent buffer's link
        aBlockPtr.iParentBuffer->iNextFreeBlock = NULL;
    }
    else
    {
        // Removing from middle of the free list
        aBlockPtr.iPrevFreeBlock->iNextFreeBlock = aBlockPtr.iNextFreeBlock;
        aBlockPtr.iNextFreeBlock->iPrevFreeBlock = aBlockPtr.iPrevFreeBlock;
    }

    aBlockPtr.iNextFreeBlock = NULL;
    aBlockPtr.iPrevFreeBlock = NULL;

    aBlockPtr.iParentBuffer->iAllocatedSz += aBlockPtr.iBlockSize;

    // Resize the block if too large
    uint32 extraspace = aBlockPtr.iBlockSize - iBlockInfoAlignedSize - aNumAlignedBytes;
    if (extraspace > (iBlockInfoAlignedSize + OSCLMEMPOOLRESIZABLEALLOCATOR_MIN_BUFFERSIZE))
    {
        trim(aBlockPtr.iBlockBuffer, extraspace);
    }

#if OSCL_MEM_FILL_WITH_PATTERN
    oscl_memset(aBlockPtr.iBlockBuffer, 0x55, (aBlockPtr.iBlockSize - iBlockInfoAlignedSize));
#endif
    return aBlockPtr.iBlockBuffer;
}


void OsclMemPoolResizableAllocator::deallocateblock(MemPoolBlockInfo& aBlockPtr)
{
    OSCL_ASSERT(aBlockPtr.iParentBuffer);

    MemPoolBufferInfo* bufferinfo = aBlockPtr.iParentBuffer;
    MemPoolBlockInfo* rightblockinfo = bufferinfo->iNextFreeBlock;
    MemPoolBlockInfo* leftblockinfo = NULL;

    // Go through the free block list and find the free block which would
    // become the right neighbor of the block being freed
    while (rightblockinfo != NULL)
    {
        if (&aBlockPtr < rightblockinfo)
        {
            break;
        }
        leftblockinfo = rightblockinfo;
        rightblockinfo = rightblockinfo->iNextFreeBlock;
    }

    // Check where the newly freed block is in the list
    if (leftblockinfo == NULL && rightblockinfo == NULL)
    {
        // The free block list is empty.
        // Trivial case so add to list and return to list without merge
        bufferinfo->iNextFreeBlock = &aBlockPtr;
        aBlockPtr.iNextFreeBlock = NULL;
        aBlockPtr.iPrevFreeBlock = NULL;
        aBlockPtr.iParentBuffer->iAllocatedSz -= aBlockPtr.iBlockSize;
        return;
    }
    else if (leftblockinfo != NULL && rightblockinfo == NULL)
    {
        // Adding to the end of the list
        OSCL_ASSERT(leftblockinfo->iNextFreeBlock == NULL);

        // Check that the newly freed block doesn't overlap with an existing free block
        if (((uint8*)leftblockinfo + leftblockinfo->iBlockSize) > (uint8*)&aBlockPtr)
        {
            OSCL_LEAVE(OsclErrArgument);
        }

        leftblockinfo->iNextFreeBlock = &aBlockPtr;
        aBlockPtr.iPrevFreeBlock = leftblockinfo;
        aBlockPtr.iNextFreeBlock = NULL;
    }
    else if (leftblockinfo == NULL && rightblockinfo != NULL)
    {
        // Adding to the beginning of the list
        OSCL_ASSERT(rightblockinfo->iPrevFreeBlock == NULL);

        // Check that the newly freed block doesn't overlap with an existing free block
        if (((uint8*)&aBlockPtr + aBlockPtr.iBlockSize) > (uint8*)rightblockinfo)
        {
            OSCL_LEAVE(OsclErrArgument);
        }

        bufferinfo->iNextFreeBlock = &aBlockPtr;
        rightblockinfo->iPrevFreeBlock = &aBlockPtr;
        aBlockPtr.iPrevFreeBlock = NULL;
        aBlockPtr.iNextFreeBlock = rightblockinfo;
    }
    else
    {
        // Adding to the middle of the list
        OSCL_ASSERT(leftblockinfo->iNextFreeBlock == rightblockinfo);
        OSCL_ASSERT(rightblockinfo->iPrevFreeBlock == leftblockinfo);

        // Check that the newly freed block doesn't overlap with the existing free blocks
        if (((uint8*)&aBlockPtr + aBlockPtr.iBlockSize) > (uint8*)rightblockinfo ||
                ((uint8*)leftblockinfo + leftblockinfo->iBlockSize) > (uint8*)&aBlockPtr)
        {
            OSCL_LEAVE(OsclErrArgument);
        }

        leftblockinfo->iNextFreeBlock = &aBlockPtr;
        rightblockinfo->iPrevFreeBlock = &aBlockPtr;
        aBlockPtr.iPrevFreeBlock = leftblockinfo;
        aBlockPtr.iNextFreeBlock = rightblockinfo;
    }
    aBlockPtr.iParentBuffer->iAllocatedSz -= aBlockPtr.iBlockSize;

    // Merge the newly freed block with neighbors if contiguous
    // Check which neighbors are contiguous in memory space
    bool rightadj = false;
    bool leftadj = false;
    if (aBlockPtr.iPrevFreeBlock)
    {
        MemPoolBlockInfo* leftnb = aBlockPtr.iPrevFreeBlock;
        if (((uint8*)leftnb + leftnb->iBlockSize) == (uint8*)&aBlockPtr)
        {
            leftadj = true;
        }
    }
    if (aBlockPtr.iNextFreeBlock)
    {
        MemPoolBlockInfo* rightnb = aBlockPtr.iNextFreeBlock;
        if (((uint8*)&aBlockPtr + aBlockPtr.iBlockSize) == (uint8*)rightnb)
        {
            rightadj = true;
        }
    }

    // Do the merge based on the check
    if (leftadj == false && rightadj == true)
    {
        // Merge the right neighbor with the newly freed block
        // Update newly freed block's size and remove the right neighbor from the list
        MemPoolBlockInfo* midblock = &aBlockPtr;
        MemPoolBlockInfo* rightblock = aBlockPtr.iNextFreeBlock;
        // Size update
        midblock->iBlockSize += rightblock->iBlockSize;
        // Right neighbor removal
        if (rightblock->iNextFreeBlock)
        {
            rightblock->iNextFreeBlock->iPrevFreeBlock = midblock;
        }
        midblock->iNextFreeBlock = rightblock->iNextFreeBlock;
    }
    else if (leftadj == true && rightadj == false)
    {
        // Merge the newly freed block with the left neighbor
        // Update the left neighbor's block size to include the newly freed block and
        // remove the newly freed block from the list
        MemPoolBlockInfo* midblock = &aBlockPtr;
        MemPoolBlockInfo* leftblock = aBlockPtr.iPrevFreeBlock;
        // Size update
        leftblock->iBlockSize += midblock->iBlockSize;
        // Newly freed block removal
        if (midblock->iNextFreeBlock)
        {
            midblock->iNextFreeBlock->iPrevFreeBlock = leftblock;
        }
        leftblock->iNextFreeBlock = midblock->iNextFreeBlock;
    }
    else if (leftadj == true && rightadj == true)
    {
        // Merge the newly freed block and right neighbor with the left neighbor
        // and remove the newly freed block and right neighbor from the list
        MemPoolBlockInfo* midblock = &aBlockPtr;
        MemPoolBlockInfo* leftblock = aBlockPtr.iPrevFreeBlock;
        MemPoolBlockInfo* rightblock = aBlockPtr.iNextFreeBlock;
        // Size update
        leftblock->iBlockSize += (midblock->iBlockSize + rightblock->iBlockSize);
        // Newly freed and right neighbor block removal
        if (rightblock->iNextFreeBlock)
        {
            rightblock->iNextFreeBlock->iPrevFreeBlock = leftblock;
        }
        leftblock->iNextFreeBlock = rightblock->iNextFreeBlock;
    }
}


bool OsclMemPoolResizableAllocator::validateblock(OsclAny* aBlockBufPtr)
{
    uint32 i = 0;

    if (aBlockBufPtr == NULL)
    {
        // Invalid pointer
        return false;
    }

    // Check if the pointer falls within one of the memory pool buffer's memory address
    for (i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
        if (aBlockBufPtr > bufferinfo->iStartAddr && aBlockBufPtr < bufferinfo->iEndAddr)
        {
            break;
        }
    }
    if (i >= iMemPoolBufferList.size())
    {
        // Parent buffer is not part of this memory pool instance
        return false;
    }

    // Retrieve the block info header
    MemPoolBlockInfo* chkblock = (MemPoolBlockInfo*)((uint8*)aBlockBufPtr - iBlockInfoAlignedSize);

    if (chkblock->iBlockPreFence != OSCLMEMPOOLRESIZABLEALLOCATOR_PREFENCE_PATTERN ||
            chkblock->iBlockPostFence != OSCLMEMPOOLRESIZABLEALLOCATOR_POSTFENCE_PATTERN)
    {
        // Memory fence checking failed
        return false;
    }

    // Check the parent buffer is one in the list
    MemPoolBufferInfo* parentbuffer = chkblock->iParentBuffer;
    if (parentbuffer == NULL)
    {
        return false;
    }
    for (i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        if (parentbuffer == iMemPoolBufferList[i])
        {
            break;
        }
    }
    if (i >= iMemPoolBufferList.size())
    {
        // Parent buffer is not part of this memory pool instance
        return false;
    }

    if (aBlockBufPtr < parentbuffer->iStartAddr || aBlockBufPtr > parentbuffer->iEndAddr)
    {
        // The address of the buffer is not part of the parent buffer
        return false;
    }

    if ((OsclAny*)((uint8*)chkblock + chkblock->iBlockSize - 1) > (parentbuffer->iEndAddr))
    {
        // The block size is too big
        return false;
    }

    return true;
}


OSCL_EXPORT_REF uint32 OsclMemPoolResizableAllocator::getBufferSize() const
{
    if (iMemPoolBufferNumLimit == 0)
        OSCL_LEAVE(OsclErrNotSupported);

    uint32 bufferSize = 0;
    for (uint32 i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
        bufferSize += getMemPoolBufferSize(bufferinfo);
    }

    return bufferSize;
}

OSCL_EXPORT_REF uint32 OsclMemPoolResizableAllocator::getAllocatedSize() const
{
    //const uint32 expectedNumBlocksPerBuffer = iExpectedNumBlocksPerBuffer > 0 ? iExpectedNumBlocksPerBuffer : OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER;
    uint32 allocatedSz = 0;
    for (uint32 i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
        allocatedSz += getMemPoolBufferAllocatedSize(bufferinfo);
    }
    return allocatedSz;
}

OSCL_EXPORT_REF uint32 OsclMemPoolResizableAllocator::getAvailableSize() const
{
    if (iMemPoolBufferNumLimit == 0)
        OSCL_LEAVE(OsclErrNotSupported);

    uint32 availableSize = 0;
    for (uint32 i = 0; i < iMemPoolBufferList.size(); ++i)
    {
        MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
        uint32 memPoolBufferAvailableSz = 0;
        memPoolBufferAvailableSz = (getMemPoolBufferSize(bufferinfo) - getMemPoolBufferAllocatedSize(bufferinfo));
        availableSize += memPoolBufferAvailableSz;
    }

    return availableSize;
}

OSCL_EXPORT_REF uint32 OsclMemPoolResizableAllocator::getLargestContiguousFreeBlockSize() const
{
    uint32 blockSz = 0;

    if (iMemPoolBufferNumLimit > 0)
    {
        for (uint32 i = 0; i < iMemPoolBufferList.size(); ++i)
        {
            MemPoolBufferInfo* bufferinfo = iMemPoolBufferList[i];
            if (bufferinfo)
            {
                MemPoolBlockInfo* blockinfo = bufferinfo->iNextFreeBlock;
                while (blockinfo != NULL)
                {
                    if (blockinfo->iBlockSize > blockSz) blockSz = blockinfo->iBlockSize;
                    blockinfo = blockinfo->iNextFreeBlock;
                }
            }
        }
    }
    else
        OSCL_LEAVE(OsclErrNotSupported);

    if (blockSz > iBlockInfoAlignedSize) blockSz -= iBlockInfoAlignedSize;
    else blockSz = 0;

    return blockSz;
}

OSCL_EXPORT_REF bool OsclMemPoolResizableAllocator::setMaxSzForNewMemPoolBuffer(uint32 aMaxNewMemPoolBufferSz)
{
    bool retval = true;
    if (iMemPoolBufferNumLimit > 0)
        iMaxNewMemPoolBufferSz = aMaxNewMemPoolBufferSz;
    else
        retval = false;
    return retval;
}

uint32 OsclMemPoolResizableAllocator::getMemPoolBufferSize(MemPoolBufferInfo* aBufferInfo) const
{
    uint32 memPoolBufferSz = 0;

    if (aBufferInfo)
        memPoolBufferSz = aBufferInfo->iBufferSize;

    return memPoolBufferSz;
}

uint32 OsclMemPoolResizableAllocator::getMemPoolBufferAllocatedSize(MemPoolBufferInfo* aBufferInfo) const
{
    return aBufferInfo->iAllocatedSz;
    /*
    uint32 allocatedSz = 0;
    const uint32 expectedNumBlocksPerBuffer = iExpectedNumBlocksPerBuffer > 0 ? iExpectedNumBlocksPerBuffer : OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER;

    if (aBufferInfo)
    {
        if (aBufferInfo->iNumOutstanding > expectedNumBlocksPerBuffer)
        {
            allocatedSz = (aBufferInfo->iAllocatedSz - (expectedNumBlocksPerBuffer * iBlockInfoAlignedSize));
        }
        else
        {
            allocatedSz = (aBufferInfo->iAllocatedSz - (aBufferInfo->iNumOutstanding * iBlockInfoAlignedSize));
        }
    }
    return allocatedSz;
    */
}

uint32 OsclMemPoolResizableAllocator::memoryPoolBufferMgmtOverhead() const
{
    uint32 overheadBytes = iBufferInfoAlignedSize;
    if (iExpectedNumBlocksPerBuffer > 0)
    {
        overheadBytes += (iExpectedNumBlocksPerBuffer * iBlockInfoAlignedSize);
    }
    else
    {
        overheadBytes += (OSCLMEMPOOLRESIZABLEALLOCATOR_DEFAULT_NUMBLOCKPERBUFFER * iBlockInfoAlignedSize);
    }
    return overheadBytes;
}