Array -Keys Overview

Purpose

Defines a property of an array element -by which a heap based array can sorted and searched.

Architectural relationships

Keys are declared by -client programs, and used in conjunction with the heap based array classes -defined by the Dynamic Arrays API.

Keys are also used by the low-level -sorting functions supplied by the System Static Functions API.

Description

The API has four key concepts: abstract -key base, fixed-length element array key, variable-length element array key, -packed array key, and array element swap operation base.

General -properties

A key specifies a data member within a type. It allows -the caller to manipulate an array of elements of this type. The Symbian platform -array classes have member functions for sorting, finding, and inserting elements -by key.

Concrete classes are defined for each of the basic Symbian -platform array types, fixed length, variable length, and packed.

Abstract key base

The abstract key base defines the characteristics -of a key and defines the basic behaviour of keys. The most important properties -of a key are:

location: defines which -data member of the array element type should be used for sorting, etc.
type: whether the data -member is a descriptor, text (NULL terminated string), or a number.

The abstract key base interface is provided by TKey.

Fixed-length array key

The fixed-length element array key -specifies the key to be used with fixed-length element (CArrayFix -based) -arrays.

The abstract key base interface is provided by TKeyArrayFix.

Variable-length array key

The variable-length element array -key specifies the key to be used with variable-length element (CArrayVar -based) -arrays, and for sorting packed (CArrayPakFlat -based) arrays.

The -variable length array key interface is provided by TKeyArrayVar.

Packed array key

The packed array key specifies the key to -be used for searching and inserting elements by key with packed (CArrayPakFlat -based) -arrays.

The packed array key interface is provided by TKeyArrayPak.

Array element swap operation base

If a client uses the sort -function provided by the System Static Functions API, instead of sorting through -the Symbian platform array classes, it must define a class able to swap elements.

The -array element swap operation base interface is provided by TSwap.

See also

Dynamic -Arrays Overview

System -Static Functions Overview

+ + + + + +Array +Keys OverviewThe document provides an overview of array keys. +

Purpose

Defines a property of an array element +by which a heap based array can sorted and searched.

Architectural relationships

Keys are declared by +client programs, and used in conjunction with the heap based array classes +defined by the Dynamic Arrays API.

Keys are also used by the low-level +sorting functions supplied by the System Static Functions API.

Description

The API has four key concepts: abstract +key base, fixed-length element array key, variable-length element array key, +packed array key, and array element swap operation base.

General +properties

A key specifies a data member within a type. It allows +the caller to manipulate an array of elements of this type. The Symbian platform +array classes have member functions for sorting, finding, and inserting elements +by key.

Concrete classes are defined for each of the basic Symbian +platform array types, fixed length, variable length, and packed.

Abstract key base

The abstract key base defines the characteristics +of a key and defines the basic behaviour of keys. The most important properties +of a key are:

location: defines which +data member of the array element type should be used for sorting, etc.
type: whether the data +member is a descriptor, text (NULL terminated string), or a number.

The abstract key base interface is provided by TKey.

Fixed-length array key

The fixed-length element array key +specifies the key to be used with fixed-length element (CArrayFix -based) +arrays.

The abstract key base interface is provided by TKeyArrayFix.

Variable-length array key

The variable-length element array +key specifies the key to be used with variable-length element (CArrayVar -based) +arrays, and for sorting packed (CArrayPakFlat -based) arrays.

The +variable length array key interface is provided by TKeyArrayVar.

Packed array key

The packed array key specifies the key to +be used for searching and inserting elements by key with packed (CArrayPakFlat -based) +arrays.

The packed array key interface is provided by TKeyArrayPak.

Array element swap operation base

If a client uses the sort +function provided by the System Static Functions API, instead of sorting through +the Symbian platform array classes, it must define a class able to swap elements.

The +array element swap operation base interface is provided by TSwap.