<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML> <HEAD> <TITLE>Class Template symmetric_filter</TITLE> <LINK REL="stylesheet" HREF="../../../../boost.css"> <LINK REL="stylesheet" HREF="../theme/iostreams.css"> </HEAD> <BODY> <!-- Begin Banner --> <H1 CLASS="title">Class Template <CODE>symmetric_filter</CODE></H1> <HR CLASS="banner"> <!-- End Banner --> <DL class="page-index"> <DT><A href="#description">Description</A></DT> <DT><A href="#headers">Headers</A></DT> <DT><A href="#reference">Reference</A></DT> <DT><A href="#examples">Examples</A></DT> </DL> <HR> <A NAME="description"></A> <H2>Description</H2> <P> The class template <CODE>symmetric_filter</CODE> is tool for generating models of <A HREF="../concepts/dual_use_filter.html">DualUseFilter</A> from models of <A HREF="../concepts/symmetric_filter.html">SymmetricFilter</A>. It is useful for defining filters based on C language APIs. </P> <P> The Iostreams library uses <CODE>symmetric_filter</CODE> to implement the <A HREF="zlib.html">Zlib</A> and <A HREF="bzip2.html">Bzip2</A> Filters. </P> <A NAME="headers"></A> <H2>Headers</H2> <DL class="page-index"> <DT><A CLASS="header" HREF="../../../../boost/iostreams/filter/symmetric.hpp"><CODE><boost/iostreams/filter/symmetric.hpp></CODE></A></DT> </DL> <A NAME="reference"></A> <H2>Reference</H2> <H4>Synopsis</H4> <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams { <SPAN CLASS="keyword">template</SPAN>< <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">SymmetricFilter</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Alloc</A> = std::allocator<...> > <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">symmetric_filter</A> { <SPAN CLASS="keyword">public</SPAN>: <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="../guide/traits.html">char_type_of</A><SymmetricFilter>::type char_type; <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="omitted">implementation-defined</SPAN> category; <SPAN CLASS="keyword">explicit</SPAN> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size); <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size, <SPAN CLASS="keyword">const</SPAN> T0& t0); <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0, <SPAN CLASS="keyword">typename</SPAN> T1> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size, <SPAN CLASS="keyword">const</SPAN> T0& t0, <SPAN CLASS="keyword">const</SPAN> T1& t1); <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0, ..., <SPAN CLASS="keyword">typename</SPAN> TN> symmetric_filter( <SPAN CLASS="keyword">int</SPAN> buffer_size, const T0& t0, <SPAN CLASS="keyword">const</SPAN> T1& t1, ..., <SPAN CLASS="keyword">const</SPAN> TN& tN ); <SPAN CLASS="omitted">...</SPAN> <SPAN CLASS="keyword">protected</SPAN>: SymmetricFilter& <A CLASS="documented" HREF="#filter">filter</A>(); std::basic_string<char_type, Alloc> <A CLASS="documented" HREF="#unconsumed_input">unconsumed_input</A>() <SPAN CLASS="keyword">const</SPAN>; }; } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE> <A NAME="template_params"></A> <H4>Template parameters</H4> <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2> <TR> <TR> <TD VALIGN="top"><I>SymmetricFilter</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> <TD>A model of <A HREF="../concepts/symmetric_filter.html">SymmetricFilter</A></TD> </TR> <TR> <TD VALIGN="top"><I>Alloc</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> <TD>A standard library allocator type (<A CLASS="bib_ref" HREF="../bibliography.html#iso">[ISO]</A>, 20.1.5), used to allocate a character buffer</TD> </TR> </TABLE> <A NAME="first_ctor"></A> <H4><CODE>symmetric_filter::symmetric_filter</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">explicit</SPAN> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size);</PRE> <P>Constructs an instance of <CODE>symmetric_filter</CODE> based on a default-constructed instance of the template parameter <A HREF="#template_params"><CODE>SymmetricFilter</CODE></A> and having an internal buffer of size <CODE>buffer_size</CODE>.</P> <A NAME="forwarding_ctors"></A> <H4><CODE>symmetric_filter::symmetric_filter</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size, <SPAN CLASS="keyword">const</SPAN> T0& t0); <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0, <SPAN CLASS="keyword">typename</SPAN> T1> symmetric_filter(<SPAN CLASS="keyword">int</SPAN> buffer_size, <SPAN CLASS="keyword">const</SPAN> T0& t0, <SPAN CLASS="keyword">const</SPAN> T1& t1); <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> T0, ..., <SPAN CLASS="keyword">typename</SPAN> TN> symmetric_filter( <SPAN CLASS="keyword">int</SPAN> buffer_size, <SPAN CLASS="keyword">const</SPAN> T0& t0, <SPAN CLASS="keyword">const</SPAN> T1& t1, ..., <SPAN CLASS="keyword">const</SPAN> TN& tN );</PRE> <P>Each member constructs an instance of <CODE>symmetric_filter</CODE> based on an instance of the template parameter <A HREF="#template_params"><CODE>SymmetricFilter</CODE></A> constructed with the given sequence of arguments and having an internal buffer of size <CODE>buffer_size</CODE>.</P> <A NAME="filter"></A> <H4><CODE>symmetric_filter::filter</CODE></H4> <PRE CLASS="broken_ie"> SymmetricFilter& <A CLASS="documented" HREF="#filter">filter</A>();</PRE> <P>Returns a reference to the underlying instance of <CODE>SymmetricFilter</CODE>.</P> <A NAME="unconsumed_input"></A> <H4><CODE>symmetric_filter::unconsumed_input</CODE></H4> <PRE CLASS="broken_ie"> std::basic_string<char_type, Alloc> <A CLASS="documented" HREF="#unconsumed_input">unconsumed_input</A>() <SPAN CLASS="keyword">const</SPAN>;</PRE> <P>Returns any uncomsumed data remaining in the internal buffer as a standard string. Valid from the time the end of a stream is reached — that is, from the time <CODE><A HREF="../concepts/symmetric_filter.html">SymmetricFilter::filter</A></CODE> returns <CODE>false</CODE> — until <CODE>filter</CODE> is invoked to begin processing a new sequence of data.</P> <A NAME="examples"></A> <H2>Examples</H2> <P>For example uses of <CODE>symmetric_filter</CODE>, see the headers <A CLASS="header" HREF="../../../../boost/iostreams/filter/zlib.hpp"><CODE><boost/iostreams/filter/zlib.hpp></CODE></A> and <A CLASS="header" HREF="../../../../boost/iostreams/filter/bzip2.hpp"><CODE><boost/iostreams/filter/bzip2.hpp></CODE></A> and the corresponding implementation files <A CLASS="header" HREF="../../src/zlib.cpp"><CODE><libs/iostreams/src/zlib.cpp></CODE></A> and <A CLASS="header" HREF="../../src/bzip2.cpp"><CODE><libs/iostreams/src/bzip2.cpp></CODE></A>.</P> <!-- Begin Footer --> <HR> <P CLASS="copyright">Revised 02 Feb 2008</P> <P CLASS="copyright">© Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</a><br/>© Copyright 2004-2007 <a href="http://www.coderage.com/turkanis/" target="_top">Jonathan Turkanis</a></P> <P CLASS="copyright"> Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <A HREF="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>) </P> <!-- End Footer --> </BODY>