int MainObjectArrayPtr::MainObjectArray::PutElement(
    ObjectNumber p_MainObjectNumber, ArrayIndex p_ElementIndex, 
    ModifiableElement p_Element)
{
    MainObjectEntry BPAQuantumNumber;
    BigPointerBlockPtr BigPointerBlock;
    LittlePointerBlockPtr LittlePointerBlock;
    LeafBlockPtr ElementBlock;
    ArrayIndex BigPointerIndex;
    ArrayIndex LittlePointerIndex;
    QuantumNumber LPAQuantumNumber;
    ItemReference ElementRef;
    ItemReference NewElementRef;
    ModifiableElement Element;
    QFreeSpaceEntry SpaceAvailable;
    QuantumNumber NewQuantum;
    QuantumNumber PossibleQuantum;
    LeafBlockPtr NewElementBlock;
    ArrayIndex FreeSpace;
    ArrayIndex ActualFreeSpace;
    ArrayIndex NewItemNumber;
    ObjectNumber LeafObjectNumber;

    qfassert (p_Element.GetSize() < MaxItemSize);

    BigPointerIndex = p_ElementIndex / ItemReferencesPerBlock;

    BPAQuantumNumber = Get(p_MainObjectNumber);

    BigPointerBlock = m_QuantumFile->MakeBigPointerBlockPtr(BPAQuantumNumber);

    LPAQuantumNumber = BigPointerBlock->GetBigArrayElement(BigPointerIndex);

    LittlePointerBlock = 
        m_QuantumFile->MakeLittlePointerBlockPtr(LPAQuantumNumber);

    LittlePointerIndex = p_ElementIndex % ItemReferencesPerBlock;
    ElementRef = LittlePointerBlock->GetLittleArrayElement(LittlePointerIndex);

    if (ElementRef.IsReference())
        {
        ElementBlock = 
            m_QuantumFile->MakeLeafBlockPtr(ElementRef.GetQuantumNumber());
        ElementBlock->DeleteItem(ElementRef.GetItemNumber());
        }

    if (p_Element.GetSize() == 0) // nothing to store
        {
        ElementRef.SetQuantumNumber(NoQuantum);
        ElementRef.SetItemNumber(NoItem);
        LittlePointerBlock->SetLittleArrayElement(LittlePointerIndex,ElementRef);
        return 0;
        }

    NewQuantum = NoQuantum;
    PossibleQuantum = BigPointerBlock->GetLastQuantumAddedTo();
    if (PossibleQuantum != NoQuantum)
       {
       SpaceAvailable = m_QuantumFile->QGetFreeSpace(PossibleQuantum);
       FreeSpace = SpaceAvailable.m_FreeSpaceCode * FreeSpaceConversion;
       if (SpaceAvailable.m_FreeSpaceCode != AvailableQuantum &&
         FreeSpace > p_Element.GetSize())
        {
        NewElementBlock = m_QuantumFile->MakeLeafBlockPtr(PossibleQuantum);
        ActualFreeSpace = NewElementBlock->CalculateFreeSpace();
        if (ActualFreeSpace > p_Element.GetSize())
            NewQuantum = PossibleQuantum;
        }
       }

    if (NewQuantum == NoQuantum)
        {
        NewQuantum = m_QuantumFile->FindSpaceForItem(p_MainObjectNumber, 
            p_Element.GetSize());
        NewElementBlock = m_QuantumFile->MakeLeafBlockPtr(NewQuantum);
        LeafObjectNumber = NewElementBlock->GetMainObjectNumber();
        qfassert(LeafObjectNumber == p_MainObjectNumber);
        }

    BigPointerBlock->SetLastQuantumAddedTo(NewQuantum);
    NewElementRef.SetQuantumNumber(NewQuantum);

    NewItemNumber = NewElementBlock->AddItem(p_Element, 
        VARIABLE_LENGTH_STRING, p_ElementIndex);
    NewElementRef.SetItemNumber(NewItemNumber);

    LeafObjectNumber = NewElementBlock->GetMainObjectNumber();
    qfassert(LeafObjectNumber == p_MainObjectNumber);

    NewElementBlock->UpdateFreeSpace();

    LittlePointerBlock->SetLittleArrayElement(LittlePointerIndex,NewElementRef);

    return 0;
}