overlist.cpp

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// $Id: overlist.cpp 1282 2006-06-09 09:46:49Z alex $
/* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
================================XARAHEADERSTART===========================
 
               Xara LX, a vector drawing and manipulation program.
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----------------------------------

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 */
// Imagemap class

#include "camtypes.h"
#include "overlist.h"
//#include "list.h" - in camtypes.h [AUTOMATICALLY REMOVED]



CC_IMPLEMENT_DYNAMIC(OverrideList, List)

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

    OverrideList::OverrideList()

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Purpose:    Default constructor
    
********************************************************************************************/

OverrideList::OverrideList() : List()
{
}

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

    virtual void OverrideList::AddHead( OverrideListItem* poliToAdd)

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                If this list item overrides any items already present
                in the list, the items in the list are deleted and this
                list item is added.

                If any item in the list overrides this list item,
                this list item is not added to the list.

                This function simply calls the InsertBefore function.

  SeeAlso:      OverrideList::InsertBefore()
    
********************************************************************************************/

void OverrideList::AddHead( OverrideListItem* poliToAdd)
{
    if (poliToAdd==NULL)
    {
        ERROR2RAW("OverrideList::AddHead - NULL parameter");
        return;
    }

    //Get the first item in the list
    OverrideListItem* pliFirst=(OverrideListItem*) GetHead();

    //Was there anything in the list?
    if (pliFirst!=NULL)              
    {
        //Yes. So call our InsertBefore function
        InsertBefore(pliFirst, poliToAdd);
    }
    else
    {
        //No. So we need do no special checking - simply insert
        //the list item
        List::AddHead(poliToAdd);
    }
    
}

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

    virtual void OverrideList::AddTail( OverrideListItem* poliToAdd)

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                If this list item overrides any items already present
                in the list, the items in the list are deleted and this
                list item is added.

                If any item in the list overrides this list item,
                this list item is not added to the list.

                This function simply calls the InsertAfter function.

  SeeAlso:      OverrideList::InsertAfter()
    
********************************************************************************************/

void OverrideList::AddTail( OverrideListItem* poliToAdd)
{
    if (poliToAdd==NULL)
    {
        ERROR2RAW("OverrideList::AddTail - NULL parameter");
        return;
    }

    //Get the last item in the list
    OverrideListItem* pliLast=(OverrideListItem*) GetTail();

    //Was there anything in the list?
    if (pliLast!=NULL)               
    {
        //Yes. So call our InsertAfter function
        InsertAfter(pliLast, poliToAdd);
    }
    else
    {
        //No. So we need do no special checking - simply insert
        //the list item
        List::AddTail(poliToAdd);
    }

    //And add our item after it
    InsertAfter(pliLast, poliToAdd);
    
}

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

    virtual ListItem* OverrideList::InsertBefore(OverrideListItem* here, OverrideListItem* item);

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                It does this by calling the function 
                OverrideListItem::OverrideFromBelow on all items
                below the insertion position, and MergeListItem::OverrideFromAbove
                on all items above the insertion position.

                If this list item overrides any items already present
                in the list, the items in the list are deleted and this
                list item is added.

                If any item in the list overrides this list item,
                this list item is not added to the list.

                This function simply calls the InsertBefore function.

  SeeAlso:      OverrideList::InsertBefore()
    
********************************************************************************************/

ListItem* OverrideList::InsertBefore(OverrideListItem* pliInsertPoint, OverrideListItem* pliToInsert)
{
    ERROR2IF(pliToInsert==NULL, NULL, "OverrideList::InsertBefore - NULL parameter");
        
    //This variable will tell us whether to insert pliToInsert
    //into the list
    BOOL fInsert=TRUE;

    //First compare pliToInsert with everything below pliInsertPoint in the list
    fInsert=CompareWithItemsBelow(pliInsertPoint, pliToInsert);

    //Now get the list item above pliInsertPoint
    OverrideListItem* pliTest=(OverrideListItem*) GetPrev(pliInsertPoint);

    //If there is anything above pliInsertPoint
    if (fInsert && pliTest!=NULL)
    {
        //Then test everything above pliInsertPoint
        fInsert=CompareWithItemsAbove(pliInsertPoint, pliToInsert);
    }

    //So, should we insert pliToInsert?
    if (fInsert)
        //Yes. So do it.
        return List::InsertBefore(pliInsertPoint, pliToInsert);
    else
        //No. So return an error value.
        return NULL;
    
}

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

    virtual ListItem* OverrideList::InsertBefore(OverrideListItem* here, OverrideListItem* item);

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                This function simply calls the other InsertBefore override.
                                
  SeeAlso:      OverrideList::InsertBefore()
    
********************************************************************************************/

LISTPOS OverrideList::InsertBefore(LISTPOS here, OverrideListItem* item)
{

    ERROR2IF(item==NULL, NULL, "OverrideList::InsertBefore - NULL parameter");
        

    //First find the list item at the position we have been given
    OverrideListItem* pliInsertionPoint=(OverrideListItem*) FindItem(here);

    //If we have not found it, return -1
    if (pliInsertionPoint==NULL)
        return -1;

    //Otherwise, call our other function to do the insertion
    OverrideListItem* pliResult=(OverrideListItem*) InsertBefore(pliInsertionPoint, item);

    //If we have been returned NULL, then return an error value
    if (pliResult==NULL)
        return -1;

    //Otherwise, find our newly returned list item in the list
    //and return it
    return FindPosition(pliResult);
    
}

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

    virtual ListItem* OverrideList::InsertAfter(OverrideListItem* here, OverrideListItem* item);

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                It does this by calling the function 
                MergeListItem::OverrideFromBelow on all items
                below the insertion position, and MergeListItem::OverrideFromAbove
                on all items above the insertion position.

                If this list item overrides any items already present
                in the list, the items in the list are deleted and this
                list item is added.

                If any item in the list overrides this list item,
                this list item is not added to the list.

                This function simply calls the InsertBefore function.

  SeeAlso:      OverrideList::InsertBefore()
    
********************************************************************************************/

ListItem* OverrideList::InsertAfter(OverrideListItem* pliInsertPoint, OverrideListItem* pliToInsert)
{
    ERROR2IF(pliToInsert==NULL, NULL, "OverrideList::InsertAfter - NULL parameter");

    //This variable will tell us whether to insert pliToInsert
    //into the list
    BOOL fInsert=TRUE;

    //First compare pliToInsert with everything above pliInsertPoint in the list
    fInsert=CompareWithItemsAbove(pliInsertPoint, pliToInsert);

    //Now get the list item after pliInsertPoint
    OverrideListItem* pliTest=(OverrideListItem*) GetNext(pliInsertPoint);

    //If there is anything before pliInsertPoint
    if (fInsert && pliTest!=NULL)
    {
        //Then test everything before pliInsertPoint
        fInsert=CompareWithItemsBelow(pliInsertPoint, pliToInsert);
    }

    //So, should we insert pliToInsert?
    if (fInsert)
        //Yes. So do it.
        return List::InsertAfter(pliInsertPoint, pliToInsert);
    else
        //No. So return an error value.
        return NULL;


    
}

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

    virtual ListItem* OverrideList::InsertAfter(OverrideListItem* here, OverrideListItem* item);

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     poliToAdd   The item to add
                
    Returns:    -

    Purpose:    Compares this list item with all the items in the list,
                to find out whether they override this list item or
                whether this list item overrides them.

                This function simply calls the other InsertAfter override.
                                
  SeeAlso:      OverrideList::InsertAfter()
    
********************************************************************************************/

LISTPOS OverrideList::InsertAfter(LISTPOS here, OverrideListItem* item)
{
    ERROR2IF(item==NULL, 0, "OverrideList::InsertAfter - NULL parameter");

    //First find the list item at the position we have been given
    OverrideListItem* pliInsertionPoint=(OverrideListItem*) FindItem(here);

    //If we have not found it, return -1
    if (pliInsertionPoint==NULL)
        return -1;

    //Otherwise, call our other function to do the insertion
    OverrideListItem* pliResult=(OverrideListItem*) InsertAfter(pliInsertionPoint, item);

    //If we have been returned NULL, then return an error value
    if (pliResult==NULL)
        return -1;

    //Otherwise, find our newly returned list item in the list
    //and return it
    return FindPosition(pliResult);
    
}

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

  Toolkit functions

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

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

    virtual BOOL OverrideList::CompareWithItemsAbove(OverrideListItem* pliStartPos, OverrideListItem* pliToInsert);

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     pliStartPos     The position to start searching from
                pliToAdd        The list items to add
                
    Returns:    FALSE   if pliToAdd was overridden by another
                        item in the list

                TRUE    if pliToAdd was not overridden

                Note that, if pliToAdd overrides another item in the list,
                this does not affect the result returned.

    Purpose:    Compares this list item with all the items 
                above pliStartPos, inclusive.
                
  SeeAlso:      OverrideList::InsertBefore(), OverrideList::After()
    
********************************************************************************************/

BOOL OverrideList::CompareWithItemsAbove(OverrideListItem* pliStartPos, OverrideListItem* pliToInsert)
{
    //This pointer will show the item we are looking at
    OverrideListItem* pliLook=pliStartPos;

    //While we are still looking at a valid item
    while (pliLook!=NULL)
    {
        //This will be the next item we look at
        //It's important to do this now - because we may delete pliLook in a moment
        OverrideListItem* pliNext=(OverrideListItem*) GetPrev(pliLook);

        //Does the item we are looking at override the item
        //we are about to insert?
        if (pliLook->OverrideFromAbove(pliToInsert))
        {
            //Yes. So return to say that we're not going to insert the
            //item
            return FALSE;
        }

        //Does the item we are about to insert override the item
        //we are looking at?
        if (pliToInsert->OverrideFromBelow(pliLook))
        {
            //Yes. So delete the item we are looking at.
            RemoveItem(pliLook);
            delete pliLook;
        }

        //And move on to the next item
        pliLook=pliNext;
    }

    //ANd return to say that pliToInsert has not been overridden
    return TRUE;
}

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

    virtual BOOL OverrideList::CompareWithItemsBelow(OverrideListItem* pliStartPos, OverrideListItem* pliToInsert)

    Author:     Graham_Walmsley (Xara Group Ltd) <camelotdev@xara.com>
    Created:    22/4/97
    Inputs:     pliStartPos     The position to start searching from
                pliToAdd        The list items to add
                
    Returns:    FALSE   if pliToAdd was overridden by another
                        item in the list

                TRUE    if pliToAdd was not overridden

                Note that, if pliToAdd overrides another item in the list,
                this does not affect the result returned.

    Purpose:    Compares this list item with all the items 
                below pliStartPos, inclusive.
                
  SeeAlso:      OverrideList::InsertBefore(), OverrideList::After()
    
********************************************************************************************/

BOOL OverrideList::CompareWithItemsBelow(OverrideListItem* pliStartPos, OverrideListItem* pliToInsert)
{
    //This pointer will show the item we are looking at
    OverrideListItem* pliLook=pliStartPos;

    //While we are still looking at a valid item
    while (pliLook!=NULL)
    {
        //This will be the next item we look at
        //It's important to do this now - because we may delete pliLook in a moment
        OverrideListItem* pliNext=(OverrideListItem*) GetNext(pliLook);

        //Does the item we are looking at override the item
        //we are about to insert?
        if (pliLook->OverrideFromBelow(pliToInsert))
        {
            //Yes. So return to say that we're not going to insert the
            //item
            return FALSE;
        }

        //Does the item we are about to insert override the item
        //we are looking at?
        if (pliToInsert->OverrideFromAbove(pliLook))
        {
            //Yes. So delete the item we are looking at.
            RemoveItem(pliLook);
            delete pliLook;
        }
                
        //And move on to the next item
        pliLook=pliNext;
    }

    //And return to say that pliToInsert has not been overridden
    return TRUE;
}



        

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