diff -r 43e37759235e -r 51a74ef9ed63 Symbian3/SDK/Source/GUID-5127C80E-EACE-5524-9A75-A0EFB41C2226.dita
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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-5127C80E-EACE-5524-9A75-A0EFB41C2226" xml:lang="en"><title>Circular
+Buffer structure</title><shortdesc>This document describes the structure of circular buffers.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>"Circular Buffers" is a sub-API of the "Buffers and strings" API.</p>
+<p>A circular buffer provides a simple way of implementing a fixed length
+queue of fixed size objects where objects are added to the head of the queue
+while items are removed from the tail of the queue.</p>
+<p>Logically, the buffer is circular with no defined start or end. Objects
+are always added to the buffer head and are always removed from the buffer
+tail. The buffer head is always the next vacant slot into which an object
+is added. The buffer tail is always the slot from which the next object is
+removed. The tail always logically follows the head and the implementation
+ensures that the tail never overtakes the head.</p>
+<fig id="GUID-18737BF9-5382-5431-8B3E-68C7CCD3DF86">
+<image href="GUID-F057FFF8-EA6A-5719-BE6B-B37950A07A7B_d0e223645_href.png" placement="inline"/>
+</fig>
+<p>Physically, the buffer is a contiguous block of memory. The implementation
+provides the appearance of circularity.</p>
+<p>A circular buffer has a maximum capacity which must be set before the circular
+buffer can be used. The maximum capacity can be changed at any time but any
+existing data within the buffer is lost.</p>
+<p>The sub-API consists of three classes, two of which can be instantiated:</p>
+<ul>
+<li id="GUID-42FC2894-0995-578C-AE0D-0670CC63B242"><p>the templated class <codeph>CCirBuf&lt;class
+T&gt;</codeph> builds a circular buffer of general objects.</p> </li>
+<li id="GUID-C98B7B84-67D4-5616-A042-CFF16B26422F"><p>the <codeph>CCirBuffer</codeph> class
+builds a circular buffer of unsigned integers with values ranging from -128
+to +128.</p> </li>
+</ul>
+</conbody></concept>
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