Symbian3/SDK/Source/GUID-D37E0579-0F3B-5EE4-8264-1358E493672B.dita
author Dominic Pinkman <Dominic.Pinkman@Nokia.com>
Wed, 31 Mar 2010 11:11:55 +0100
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Week 12 contribution of API Specs and fix SDK submission
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<?xml version="1.0" encoding="utf-8"?>
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<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
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<!-- This component and the accompanying materials are made available under the terms of the License 
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"Eclipse Public License v1.0" which accompanies this distribution, 
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and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
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<!-- Initial Contributors:
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    Nokia Corporation - initial contribution.
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Contributors: 
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-->
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<!DOCTYPE concept
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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<concept id="GUID-D37E0579-0F3B-5EE4-8264-1358E493672B" xml:lang="en"><title>Array
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of variable length elements, flat buffer</title><shortdesc>Describes how elements of varying length are organised in the array
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buffer.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
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<p>This is a <codeph>CArrayVarFlat&lt;class T&gt;</codeph> object whose
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elements can have different lengths. Although each element is a <codeph>class T</codeph> object,
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the length of that object can vary.</p>
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<p>In this type of array, each element occupies its own individual cell allocated
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from the heap. The array buffer contains fixed length data structures, one
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for each element, which are physically contiguous within the flat array buffer.
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Each fixed length data structure contains the length of an element (a <codeph>TInt</codeph> value)
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and a pointer to it. The structure itself is part of the implementation but
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occupies no more than eight bytes on 32-bit machines.</p>
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<p>A flat buffer always occupies a single cell allocated from the heap and
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is always extended by the process of reallocation. A flat array buffer is
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implemented using a <codeph>CBufFlat</codeph> object.</p>
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<p>The following diagram illustrates how elements are organised within the
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array buffer:</p>
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<fig id="GUID-2A857FBF-943D-5665-9999-BC27EA321F73">
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<image href="GUID-924E26D6-8B9D-5C76-AF61-7C5514BB3D78_d0e219442_href.png" placement="inline"/>
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</fig>
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<p>This kind of array is suitable for a small number of elements or for a
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moderately large but fixed maximum number of elements. It is not suitable
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for large arrays with a high turnover of elements. </p>
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<p>This class is immediately derived from the abstract templated base class <codeph>CArrayVar&lt;class T&gt;</codeph> which
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is itself derived from the abstract non-templated base class <codeph>CArrayVarBase</codeph>.</p>
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<section id="GUID-59ADA2D7-56B2-44C3-8E7C-A5DE5F0BBDBA"><title>See also</title> <p><xref href="GUID-112AAFA5-B4C9-5B62-A106-FB5097C13A0E.dita">Using
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Dynamic Buffers</xref>.</p> </section>
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</conbody></concept>