1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Rationale</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../circular_buffer.html" title="Chapter 8. Boost.Circular Buffer"> 10<link rel="prev" href="example.html" title="Circular_buffer example"> 11<link rel="next" href="implementation.html" title="Implementation"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> 16<td align="center"><a href="../../../index.html">Home</a></td> 17<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="example.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../circular_buffer.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="implementation.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="section"> 27<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 28<a name="circular_buffer.rationale"></a><a class="link" href="rationale.html" title="Rationale">Rationale</a> 29</h2></div></div></div> 30<p> 31 The basic motivation behind the <code class="computeroutput"><a class="link" href="../boost/circular_buffer.html" title="Class template circular_buffer">circular_buffer</a></code> 32 was to create a container which would <span class="bold"><strong>work seamlessly 33 with STL</strong></span>. 34 </p> 35<p> 36 Additionally, the design of the <code class="computeroutput"><a class="link" href="../boost/circular_buffer.html" title="Class template circular_buffer">circular_buffer</a></code> 37 was guided by the following principles: 38 </p> 39<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 40<li class="listitem"> 41 Maximum <span class="emphasis"><em>efficiency</em></span> for envisaged applications. 42 </li> 43<li class="listitem"> 44 Suitable for <span class="emphasis"><em>general purpose use</em></span>. 45 </li> 46<li class="listitem"> 47 The behaviour of the buffer as <span class="emphasis"><em>intuitive</em></span> as possible. 48 </li> 49<li class="listitem"> 50 Suitable for <span class="emphasis"><em>specialization</em></span> by means of adaptors. 51 (The <code class="computeroutput"><a class="link" href="../boost/circular_idm45227212366288.html" title="Class template circular_buffer_space_optimized">circular_buffer_space_optimized</a></code> 52 is such an example of the adaptor.) 53 </li> 54<li class="listitem"> 55 Easy to <span class="emphasis"><em>debug</em></span>. (See Debug Support for details.) 56 </li> 57</ul></div> 58<p> 59 In order to achieve maximum efficiency, the <code class="computeroutput"><a class="link" href="../boost/circular_buffer.html" title="Class template circular_buffer">circular_buffer</a></code> 60 and <code class="computeroutput"><a class="link" href="../boost/circular_idm45227212366288.html" title="Class template circular_buffer_space_optimized">circular_buffer_space_optimized</a></code> 61 store their elements in a <span class="bold"><strong>contiguous region of memory</strong></span>, 62 which then enables: 63 </p> 64<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 65<li class="listitem"> 66 Use of fixed memory and no implicit or unexpected memory allocation. 67 </li> 68<li class="listitem"> 69 Fast constant-time insertion and removal of elements from the front and 70 back. 71 </li> 72<li class="listitem"> 73 Fast constant-time random access of elements. 74 </li> 75<li class="listitem"> 76 Suitability for real-time and performance critical applications. 77 </li> 78</ul></div> 79<p> 80 Possible applications of the circular buffer include: 81 </p> 82<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 83<li class="listitem"> 84 Storage of the <span class="emphasis"><em>most recently received samples</em></span>, overwriting 85 the oldest as new samples arrive. 86 </li> 87<li class="listitem"> 88 As an underlying container for a <span class="emphasis"><em>bounded buffer</em></span> (see 89 the Bounded Buffer example, code at <a href="../../../libs/circular_buffer/example/circular_buffer_bound_example.cpp" target="_top">circular_buffer_bound_example.cpp</a>). 90 </li> 91<li class="listitem"> 92 A kind of <span class="emphasis"><em>cache</em></span> storing a specified number of last 93 inserted elements. 94 </li> 95<li class="listitem"> 96 Efficient fixed capacity <span class="emphasis"><em>FIFO (First In, First Out)</em></span>, 97 </li> 98<li class="listitem"> 99 Efficient fixed capacity <span class="emphasis"><em>LIFO (Last In, First Out)</em></span> 100 queue which removes the oldest (inserted as first) elements when full. 101 </li> 102</ul></div> 103</div> 104<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 105<td align="left"></td> 106<td align="right"><div class="copyright-footer">Copyright © 2003-2013 Jan Gaspar<p> 107 Distributed under the Boost Software License, Version 1.0. (See accompanying 108 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 109 </p> 110</div></td> 111</tr></table> 112<hr> 113<div class="spirit-nav"> 114<a accesskey="p" href="example.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../circular_buffer.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="implementation.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 115</div> 116</body> 117</html> 118
