119 lines
3.3 KiB
HTML
119 lines
3.3 KiB
HTML
<HTML>
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<!--
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Copyright (c) Jeremy Siek 2000
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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-->
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<Head>
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<Title>Buffer</Title>
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</HEAD>
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<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
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ALINK="#ff0000">
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<IMG SRC="../../../boost.png"
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ALT="C++ Boost" width="277" height="86">
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<BR Clear>
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<h3>Buffer Concept</h3>
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A Buffer is something in which items can be put and removed.
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The Buffer <i>concept</i> has very few requirements. It does
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not require any particular ordering of how the items are stored or in
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what order they will appear when removed, however, there is typically
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some sort of ordering policy.
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<h3>Notation</h3>
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<table>
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<tr> <td> <tt>B</tt> </td> <td> is a type that models Buffer. </td></tr>
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<tr> <td> <tt>T</tt> </td> <td> is the value type of <tt>B</tt>. </td></tr>
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<tr> <td> <tt>t</tt> </td> <td> is an object of type <tt>T</tt>. </td></tr>
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</table>
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<h3>Members</h3>
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For a type to model the Buffer concept it must have the following members.
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<p>
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<table border="1">
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<tr> <td><b>Member</b></td> <td><b>Description</b></td> </tr>
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<tr> <td> <tt>value_type</tt> </td>
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<td> The type of object stored in the Buffer. The value type
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must be <A href="http://www.boost.org/sgi/stl/Assignable.html">Assignable</a>.</td>
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</tr>
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<tr> <td> <tt>size_type</tt> </td>
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<td> An unsigned integral type for representing the number of
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objects in the Buffer.</td>
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</tr>
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<tr> <td> <tt>void push(const T& t)</tt> </td>
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<td> Inserts <tt>t</tt> into the Buffer. <tt>size()</tt> will be
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incremented by one.</td>
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</tr>
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<tr> <td> <tt>void pop()</tt> </td>
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<td> Removes an object from the Buffer. <tt>size()</tt> will be
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decremented by one. Precondition: <tt>empty()</tt>
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is <tt>false</tt>. </td>
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</tr>
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<tr> <td> <tt>T& top()</tt> </td>
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<td> Returns a mutable reference to some object in the Buffer.
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Precondition: <tt>empty()</tt> is <tt>false</tt>.</td>
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</tr>
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<tr> <td> <tt>const T& top() const</tt> </td>
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<td> Returns a const reference to some object in the Buffer.
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Precondition: <tt>empty()</tt> is <tt>false</tt>.</td>
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</tr>
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<tr> <td> <tt>size_type size() const</tt> </td>
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<td> Returns the number of objects in the Buffer.
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Invariant: <tt>size() >= 0</tt>. </td>
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</tr>
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<tr> <td> <tt>bool empty() const</tt> </td>
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<td> Equivalent to <tt>b.size() == 0</tt>.</td>
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</tr>
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</table>
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<h3>Complexity Guarantees</h3>
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<UL>
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<LI> <tt>push()</tt>, <tt>pop()</tt>, and <tt>size()</tt> must be at
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most linear time complexity in the size of the Generalized Queue.
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<LI> <tt>top()</tt> and <tt>empty()</tt> must be amortized constant time.
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</UL>
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<h3>Models</h3>
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<UL>
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<LI><a href="http://www.boost.org/sgi/stl/stack.html"><tt>std::stack</tt></a>
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<LI><a href="../../../boost/pending/mutable_queue.hpp"><tt>boost::mutable_queue</tt></a>
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</UL>
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<p>
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<br>
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<HR>
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<TABLE>
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<TR valign=top>
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<TD nowrap>Copyright © 2000-2001</TD><TD>
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<A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>, Indiana University and C++ Library & Compiler Group/SGI (<A HREF="mailto:jsiek@engr.sgi.com">jsiek@engr.sgi.com</A>)
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</TD></TR></TABLE>
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