<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Function Template restrict</TITLE>
<LINK REL="stylesheet" HREF="../../../../boost.css">
<LINK REL="stylesheet" HREF="../theme/iostreams.css">
</HEAD>
<BODY>
<!-- Begin Banner -->
<H1 CLASS="title">Function Template <CODE>restrict</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>
</DL>
<HR>
<A NAME="description"></A>
<H2>Description</H2>
<P>
Given a Filter or Device that provides access to a single character sequence, we can construct a second Filter or Device which provides access to contiguous subsequence of the the original sequence. This second Filter or Device is called a <I>restriction</I> of the original device. Restrictions are represented by instances of the class template <CODE>restriction</CODE>. The function template <CODE>resrict</CODE> is an <A HREF='http://www.boost.org/more/generic_programming.html#object_generator' TARGET='_top'>object generator</A> which returns an appropriate instance of <CODE>resriction</CODE> when passed a Filter or Device and a pair of values indicating the endpoints of the restricted subsequence.
</P>
<P>
The <A HREF='../guide/modes.html'>mode</A> of a <CODE>resriction</CODE> is the same as that of the underlying component. A <CODE>resriction</CODE> is <A HREF='../concepts/closable.html'>Closable</A>, <A HREF='../concepts/flushable.html'>Flushable</A>, <A HREF='../concepts/localizable.html'>Localizable</A> and <A HREF='../concepts/optimally_buffered.html'>OptimallyBuffered</A>.
</P>
<P>
The function template <a href="slice.html"><code>slice</code></a> is available as an alias of <code>restrict</code>, for platforms that treat <code>restrict</code> as a keyword.
</P>
<A NAME="headers"></A>
<H2>Headers</H2>
<DL class="page-index">
<DT><A CLASS="header" HREF="../../../../boost/iostreams/restrict.hpp"><CODE><boost/iostreams/restrict.hpp></CODE></A></DT>
</DL>
<A NAME="reference"></A>
<H2>Reference</H2>
<A NAME="synopsis"></A>
<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="#restriction_template_params">Component</A>>
<SPAN CLASS='keyword'>class</SPAN> <A CLASS='documented' HREF='#restriction'>restriction</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_ref'>char_type_of</A><Component>::type char_type;
<SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>implementation-defined</SPAN> mode;
<A CLASS='documented' HREF='#restriction_ctor'>restriction</A>( [<SPAN CLASS='keyword'>const</SPAN>] Component& component,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> off,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> len = <SPAN CLASS='literal'>-1</SPAN> );
<SPAN CLASS='comment'>// Filter or Device member functions</SPAN>
};
<SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#restrict_template_params">Component</A>>
<A CLASS='documented' HREF='#restriction'>restriction</A><Component>
<A CLASS='documented' HREF='#restrict'>restrict</A>( [<SPAN CLASS='keyword'>const</SPAN>] Component& component,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> off,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> len = <SPAN CLASS='literal'>-1</SPAN> );
} } // End namespace boost::io</PRE>
<A NAME="restriction"></A>
<H2>Class Template <CODE>restriction</CODE></H2>
<A NAME="restriction_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
<TR>
<TD VALIGN="top"><I>Component</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A> or <A HREF='../concepts/device.html'>Device</A></TD>
</TR>
</TABLE>
<A NAME="restriction_ctor"></A>
<H4><CODE>restriction::restriction</CODE></H4>
<PRE CLASS="broken_ie"> restriction( [<SPAN CLASS='keyword'>const</SPAN>] Component& component,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> off,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> len = <SPAN CLASS='literal'>-1</SPAN> );</PRE>
<P>
Constructs an instance of <CODE>restriction</CODE> based on the given component and offsets. The parameters have the following interpretation:
</P>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
<TR>
<TD VALIGN="top"><I>component</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The Filter or Device to be restricted. If <CODE>Component</CODE> is a stream or stream buffer type, the function parameter is a non-<CODE>const</CODE> reference; otherwise it is a <CODE>const</CODE> reference.</TD>
</TR>
<TR>
<TD VALIGN="top"><I>off</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The offset of the beginning of the restricted character sequence.</TD>
</TR>
<TR>
<TD VALIGN="top"><I>len</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The length of the restricted character sequence. A value of <CODE>-1</CODE> indicates that the end of the restricted sequence should be the same as that of the unrestricted sequence.</TD>
</TR>
</TABLE>
<A NAME="restrict"></A>
<H2>Function Template <CODE>restrict</CODE></H2>
<PRE CLASS="broken_ie"><SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> Component>
restriction<Component>
restrict( [<SPAN CLASS='keyword'>const</SPAN>] Component& component,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> off,
<A CLASS='documented' HREF='positioning.html#synopsis'>stream_offset</A> len = <SPAN CLASS='literal'>-1</SPAN> );</PRE>
<A NAME="restrict_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
<TR>
<TD VALIGN="top"><I>Component</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A> or <A HREF='../concepts/device.html'>Device</A></TD>
</TR>
</TABLE>
<P>
Constructs an instance of an appropriate specialization of <CODE>restriction</CODE> based on the given component and offsets. The parameters have the following interpretation:
</P>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
<TR>
<TD VALIGN="top"><I>component</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The Filter or Device to be restricted. If <CODE>Component</CODE> is a stream or stream buffer type, the function parameter is a non-<CODE>const</CODE> reference; otherwise it is a <CODE>const</CODE> reference.</TD>
</TR>
<TR>
<TD VALIGN="top"><I>off</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The offset of the beginning of the restricted character sequence.</TD>
</TR>
<TR>
<TD VALIGN="top"><I>len</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>The length of the restricted character sequence. A value of <CODE>-1</CODE> indicates that the end of the restricted sequence should be the same as that of the unrestricted sequence.</TD>
</TR>
</TABLE>
<!-- 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>
