Dynamic +Arrays Overview

Description

A large number of concrete classes +provide dynamic arrays that are suitable for different circumstances. Unlike +standard C++ arrays or the Symbian platform Fixed Size Arrays, the number +of elements in a dynamic array can be altered at run-time.

The arrays +are divided into two families:

the simple dynamic array +family is for use in most cases
the extended dynamic +array family allows advanced properties, such as the organisation of the array +storage in memory, to be specified

The array classes are all templated. The template parameter defines +the type of object which is to form an array element.

Simple +dynamic array family

The simple dynamic array family offers arrays +of objects, integers, and pointers. The array is always stored in a single +memory area.

Object arrays are provided by RArray.

Integer +arrays are provided by RArray<TInt> and RArray<TUint>.

Pointer +arrays are provided by RPointerArray.

Extended dynamic array family

The extended dynamic array family, +derived from CBase, allows the client to specify explicitly +combinations of element properties and storage type. These terms are explained +below.

Element +properties

Options for element properties are:

Fixed length

All elements are of the same size (CArrayFixBase).

Variable length

Elements can be of different sizes (CArrayVarBase).

Pointer

Elements are pointers to CBase -derived +objects.

Untyped

Elements are TAny objects.

Storage type

Options for storage type are:

Flat buffer

The elements are stored in a single memory area, +and are of fixed length.

Segmented

The elements are stored in multiple memory areas.

Packed

The elements are stored in a single memory area, but +can be of variable length.

Different storage types present trade-offs +between efficiency of memory usage and speed.

Class summary

The following matrix demonstrates the concrete +classes that are available. Storage type is shown horizontally, element properties +vertically.

+ + + +Flat + Segmented + Packed + + + Fixed-length element + + + Variable-length element + + + CBase -pointer elements + + + Untyped elements (fixed length) + + + Untyped elements (variable length) + + + + + + + +

CArrayFixFlat

CArrayFixSeg

+ + + +

CArrayVarFlat

CArrayVarSeg

CArrayPakFlat

+ + +

CArrayPtrFlat

CArrayPtrSeg

+ + + +

CArrayFixFlat<TAny>

CArrayFixSeg<TAny>

+ + + +

CArrayVar<TAny>

+ +

CArrayPak<TAny>

+ + + +

Base classes are not shown on the above table. The inheritance +hierarchies are based on the flat, segmented, packed divisions.