MUIAllocStructureMemory¶

MUIAllocStructureMemory, PtrStructMem:POINTER, TotalItems:MUIVALUE, ItemSize:MUIVALUE

Dynamically allocates (or reallocates) memory for a specified array of structures and auto increments the total items in the array, and returns a pointer to the new current item in the array of structures.

Parameters

[in|out] lpPtrStructMem - pointer to variable used to store the pointer to the allocated structure
[in] TotalItems - number of item elements currently in the structure
[in] ItemSize - size of an item element in bytes

Notes

lpPtrStructMem is an address to receive the pointer to memory location of the base structure in memory. lpPtrStructMem can be NULL if TotalItems is 0, otherwise it must contain the address of the base structure in memory if the memory is to be increased (TotalItems > 0)

ItemSize is typically the SIZEOF structure to be allocated. This function calculates for you: TotalItems * ItemSize

If lpPtrStructMem is NULL then memory object is initialized to the size of TotalItems * ItemSize and the pointer to the memory allocated is returned

Return

Returns the pointer to the new structure item or -1 if there was a problem allocating memory

Example

; Widget element
Widget     STRUCT
  dwPrice  DD ?
  dwHeight DD ?
  dwWidth  DD ?
Widge      ENDS

; pointers
pMyWidgetArray DD 0
pCurrentWidget DD 0

; Widget count
dwTotalWidgets DD 0

; Assume dwTotalWidgets was previously set to 10 beforehand

; Add a new Widget to array of Widgets
Invoke MUIAllocStructureMemory, Addr pMyWidgetArray, dwTotalWidgets, SIZEOF Widget
.IF eax == -1
    ; Error - tell user?
    ret
.ENDIF

; Save returned value as pointer to newly added element (Widget) in array
mov pCurrentWidget, eax
inc dwTotalWidgets ; update the total widgets count now

; total widgets will now be 11
; pCurrentWidget will point to this new 11th Widget