/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

#include "hgbuffermanager.h"

#include <hgwidgets/hgcacheproxymodel.h>

HgBufferManager::HgBufferManager(

    HgBufferManagerObserver* aObserver,

	int aBufferSize,

	int aBufferTreshold,

	int aInitialPosition,

:

mObserver(aObserver),

mDiff(0),

mResetOrdered(false),

mRequestStart(0),

mRequestCount(0),

mReleaseStart(0),

mReleaseCount(0)

{

        mBufferPosition = (mTotalCount - 1) - mBufferSize;

    }

        mBufferPosition = 0;

    }

    mDiff = 0;

	//request Initial Buffer

	mRequestStart = mBufferPosition;

	mRequestCount = mBufferSize;

	calculate();

}

HgBufferManager::~HgBufferManager()

{

}

void HgBufferManager::resizeCache(int newSize, int newTreshold)

{

    if (newTreshold != mBufferTreshold){

        mBufferTreshold = newTreshold;

    }

        int a = Max(0, mBufferPosition + mBufferSize/2 - newSize/2);

        int b = Min(a + newSize, mTotalCount);

            a = mTotalCount - newSize;

        }

        int c = Max(0, mBufferPosition);

        int d = Min(c + mBufferSize, mTotalCount);

            c = mTotalCount - mBufferSize;

        }

            mObserver->request(a, c-1, HgCacheProxyModel::HgRequestOrderAscending);

            mObserver->request(d, b-1, HgCacheProxyModel::HgRequestOrderAscending);

            mObserver->release(c, a-1);

            mObserver->release(b, d);

        }

        mBufferPosition = a;

        mBufferSize = newSize;

    }

}

void HgBufferManager::calculate()

{  

    HgCacheProxyModel::HgRequestOrder direction = HgCacheProxyModel::HgRequestOrderAscending;

        mResetOrdered = false;

    } else {

            mReleaseStart = mBufferPosition;

            mRequestStart = mBufferPosition + mBufferSize;

            direction = HgCacheProxyModel::HgRequestOrderAscending; 

        } else if( mDiff > 0) {

            mReleaseStart = mBufferPosition + mBufferSize - mDiff;

            mRequestStart = mBufferPosition - mDiff;

            direction = HgCacheProxyModel::HgRequestOrderDescending;

        }

    }

    // Release 

    end--;

        mObserver->release(mReleaseStart, end);

    }

    mReleaseCount = 0;

    // Request

    end--;

        mObserver->request(mRequestStart, end, direction);

	}

    mRequestCount = 0;

    // Move Buffer

    mBufferPosition -= mDiff;

    // Reset Diff

    mDiff = 0;

}

// -----------------------------------------------------------------------------

// BufferManager::SetPosition()

// -----------------------------------------------------------------------------

//

void HgBufferManager::setPosition( int aIndex )

{

    // If all the items fit in the buffer no need to move the buffer

        return;

	bool forceUpdate = false;

        forceUpdate = true;

        forceUpdate = true;

    }

    // Too large change reset whole buffer

        mRequestCount = mDiff;

        mReleaseCount = mDiff;

        calculate();

        mRequestCount = -mDiff;

        mReleaseCount = -mDiff;

        calculate();

        int diff = mDiff < 0 ? -mDiff : mDiff;

        mRequestCount = diff;

        mReleaseCount = diff;

        calculate();

    }

}

// -----------------------------------------------------------------------------

// BufferManager::ResetBuffer()

// -----------------------------------------------------------------------------

//

{

        // release Old buffer

        mReleaseStart = mBufferPosition;

        mReleaseCount = mBufferSize;

    }

    mTotalCount = aTotalCount;

    mDiff = 0;

        mBufferPosition = mTotalCount - mBufferSize;

    }

        mBufferPosition = 0;

    }

    }

    mDiff = 0;

    mResetOrdered = false;

    mRequestStart = 0;

    mRequestCount = 0;

    mReleaseStart = 0;

    mReleaseCount = 0;

}

void HgBufferManager::aboutToRemoveItem(int pos)

{

        return;

    }

        mObserver->release(pos, pos);

    }

}

void HgBufferManager::removedItem(int pos)

{

        return;

    }

    mTotalCount--;

            mBufferPosition--;

                // Requested from the end

                // Move buffer and request from the beginning 

                mBufferPosition--;

            }

        }

    }

}

void HgBufferManager::aboutToInsertItem(int pos)

{

        return;

    }

            // Release from the end of the buffer

            mObserver->release(mBufferPosition + mBufferSize - 1, mBufferPosition + mBufferSize - 1);

        }

    }

}

void HgBufferManager::insertedItem(int pos)

{

        return;

    }

    mTotalCount++;

        mObserver->request(pos, pos);

        mBufferPosition++;

    }

}

//eof