Symbian3/SDK/Source/GUID-7DDEE87B-7056-5AAA-91A1-33D3D0D50041.dita
author Dominic Pinkman <Dominic.Pinkman@Nokia.com>
Wed, 31 Mar 2010 11:11:55 +0100
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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-7DDEE87B-7056-5AAA-91A1-33D3D0D50041" xml:lang="en"><title>Array
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of packed elements, flat array</title><shortdesc>Describes arrays of packed elements in a flat.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
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<p>This is a <codeph>CArrayPakFlat&lt;class T&gt;</codeph> object whose
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elements can have different lengths but are physically contiguous within a
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flat array buffer. Each element is preceded by a <codeph>TInt</codeph> value
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to record the length of that element.</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-C36AFFF1-3BE7-5AF3-B852-B1AB3BBA257D">
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<image href="GUID-2472E5E0-C33A-51B4-8210-89D7DEFA87C8_d0e219549_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 objects or for a moderately
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large but fixed maximum number of objects. It is not suitable for large arrays
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with a high turnover of elements. </p>
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<p>A packed array has the advantage over a variable flat array in having a
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smaller memory overhead for each element. The disadvantage is that the elements
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and their preceding <codeph>TInt</codeph> values occupy a single cell which
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has a higher risk of reallocation failure in times of low memory availability.</p>
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<p>This class is immediately derived from the abstract template
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base class <codeph>CArrayPak&lt;class T&gt;</codeph> which is itself derived
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from the abstract non-templated base class <codeph>CArrayPakBase</codeph>.</p>
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<section id="GUID-0758EE5B-5846-4ABD-B2E5-DA2C0AD57032"><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>