How -to remove elements

diff -r ebc84c812384 -r 46218c8b8afa Symbian3/PDK/Source/GUID-02E674F7-86F1-5A9C-8189-F4CEE80D9FBD.dita --- a/Symbian3/PDK/Source/GUID-02E674F7-86F1-5A9C-8189-F4CEE80D9FBD.dita Thu Mar 11 15:24:26 2010 +0000 +++ b/Symbian3/PDK/Source/GUID-02E674F7-86F1-5A9C-8189-F4CEE80D9FBD.dita Thu Mar 11 18:02:22 2010 +0000 @@ -1,78 +1,78 @@ - - - - - -How -to remove elementsIt is possible to remove one or several contiguous elements from -any array. Deleting elements from an array may not automatically free up memory. -

Elements can be removed from an array.

-

The following code fragment shows the deletion of the second TElement object -from a CArrayFixFlat<class T> array:

-class TElement - { -public : - TElement(); -public : - TBuf<4> iData; - }; -CArrayFixFlat<TElement>* fixflat; -fixflat = new (ELeave) CArrayFixFlat<TElement>(3); -... -... // elements added to the array at some point -... -fixflat->Delete(1); -

To delete what are now the third and fourth elements from the array, i.e. -the two contiguous elements starting at position two, use Delete() and -specify both the starting position and the number of elements:

-fixflat->Delete(2,2); -

Notes

Deleting elements from -an array does not automatically compress the array buffer; the space allocated -to the array buffer remains unchanged. This means that adding an element to -a same length type array after deleting an element is guaranteed not -to fail. However, this is not true for a variable length array and -is only true for a packed array if the size of the new element is less than -or equal to the size of the deleted element.
Excess space in the -array buffer can be removed using the Compress() member function. -This reduces the capacity of the array. For a same length flat array, an attempt -to add an element after compression causes re-allocation of the flat buffer. -To compress the array:

fixflat->Compress();

All elements within -an array can be deleted using the Reset() function. This -function also compresses the array. Compressing the array when it is empty -causes the memory allocated to the array buffer to be freed.
For an array of pointers -to CBase derived objects (i.e. a CArrayPtrFlat or -a CArrayPtrSeg type array), some care should be taken when -deleting elements from the array. The following code fragment deletes the -last two elements from ptrflat (a CArrayPtrFlat array) -and deletes the objects that those elements point to:

TInt index; -CElement* ptr; -... -index = ptrflat->Count(); -... -ptr = (*ptrflat)[--index]; -ptrflat->Delete(index); -delete ptr; -... -ptr = ptrflat->At(--index); -ptrflat->Delete(index); -delete ptr;

In general, before the -elements of this kind of array are deleted, the CBase derived -objects to which those elements point should be destroyed. If they are not -destroyed, then a separate copy of those elements (i.e. the pointers), must be -taken to avoid orphaning the CBase derived objects on the -heap.

+ + + + + +How +to remove elementsIt is possible to remove one or several contiguous elements from +any array. Deleting elements from an array may not automatically free up memory. +

Elements can be removed from an array.

+

The following code fragment shows the deletion of the second TElement object +from a CArrayFixFlat<class T> array:

+class TElement + { +public : + TElement(); +public : + TBuf<4> iData; + }; +CArrayFixFlat<TElement>* fixflat; +fixflat = new (ELeave) CArrayFixFlat<TElement>(3); +... +... // elements added to the array at some point +... +fixflat->Delete(1); +

To delete what are now the third and fourth elements from the array, i.e. +the two contiguous elements starting at position two, use Delete() and +specify both the starting position and the number of elements:

+fixflat->Delete(2,2); +

Notes

Deleting elements from +an array does not automatically compress the array buffer; the space allocated +to the array buffer remains unchanged. This means that adding an element to +a same length type array after deleting an element is guaranteed not +to fail. However, this is not true for a variable length array and +is only true for a packed array if the size of the new element is less than +or equal to the size of the deleted element.
Excess space in the +array buffer can be removed using the Compress() member function. +This reduces the capacity of the array. For a same length flat array, an attempt +to add an element after compression causes re-allocation of the flat buffer. +To compress the array:

fixflat->Compress();

All elements within +an array can be deleted using the Reset() function. This +function also compresses the array. Compressing the array when it is empty +causes the memory allocated to the array buffer to be freed.
For an array of pointers +to CBase derived objects (i.e. a CArrayPtrFlat or +a CArrayPtrSeg type array), some care should be taken when +deleting elements from the array. The following code fragment deletes the +last two elements from ptrflat (a CArrayPtrFlat array) +and deletes the objects that those elements point to:

TInt index; +CElement* ptr; +... +index = ptrflat->Count(); +... +ptr = (*ptrflat)[--index]; +ptrflat->Delete(index); +delete ptr; +... +ptr = ptrflat->At(--index); +ptrflat->Delete(index); +delete ptr;

In general, before the +elements of this kind of array are deleted, the CBase derived +objects to which those elements point should be destroyed. If they are not +destroyed, then a separate copy of those elements (i.e. the pointers), must be +taken to avoid orphaning the CBase derived objects on the +heap.

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