<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML> <HEAD> <TITLE>Newline Filters</TITLE> <LINK REL="stylesheet" HREF="../../../../boost.css"> <LINK REL="stylesheet" HREF="../theme/iostreams.css"> </HEAD> <BODY> <!-- Begin Banner --> <H1 CLASS="title">Newline Filters</H1> <HR CLASS="banner"> <!-- End Banner --> <DL class="page-index"> <DT><A href="#overview">Overview</A></DT> <DT><A href="#headers">Headers</A></DT> <DT><A href="#synopsis">Synopsis</A></DT> <DT><A HREF="#reference">Reference</A> <DL class="page-index"> <DT>1. <A HREF="#constants">namespace <CODE>boost::iostreams::newline</CODE></A></DT> <DT>2. <A HREF="#newline_filter">Class <CODE>newline_filter</CODE></A></DT> <DT>3. <A HREF="#newline_checker">Class <CODE>newline_checker</CODE></A></DT> <DT>4. <A HREF="#newline_error">Class <CODE>newline_error</CODE></A></DT> </DL> </DT> </DL> <A NAME="overview"></A> <H2>Overview</H2> <P> Boost.Iostreams provides two components for working with line-ending conventions: the class template <A HREF="#newline_filter"><CODE>newline_filter</CODE></A> translates between line-ending conventions, and the class template <A HREF="#newline_checker"><CODE>newline_checker</CODE></A> verifies that a character sequence conforms to a given line-ending convention. </P> <A NAME="headers"></A> <H2>Headers</H2> <DL> <DT><A CLASS="header" HREF="../../../../boost/iostreams/filter/newline.hpp"><CODE><boost/iostreams/filter/newline.hpp></CODE></A></DT> </DL> <A name="synopsis"></A> <H2>Synopsis</H2> <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams { <SPAN CLASS="keyword">namespace</SPAN> <A CLASS="documented" HREF="#constants">newline</A> { <SPAN CLASS='keyword'>const</SPAN> <SPAN CLASS='keyword'>int</SPAN> <A CLASS='documented' HREF='#posix'>posix</A> = 1; <SPAN CLASS='comment'>// Use CR as line separator.</SPAN> <SPAN CLASS='keyword'>const</SPAN> <SPAN CLASS='keyword'>int</SPAN> <A CLASS="documented" HREF="#mac">mac</A> = 2; <SPAN CLASS='comment'>// Use LF as line separator.</SPAN> <SPAN CLASS='keyword'>const</SPAN> <SPAN CLASS='keyword'>int</SPAN> <A CLASS="documented" HREF="#dos">dos</A> = 4; <SPAN CLASS='comment'>// Use CRLF as line separator.</SPAN> <SPAN CLASS='keyword'>const</SPAN> <SPAN CLASS='keyword'>int</SPAN> <A CLASS="documented" HREF="#mixed">mixed</A> = 8; <SPAN CLASS='comment'>// Mixed line endings.</SPAN> <SPAN CLASS='keyword'>const</SPAN> <SPAN CLASS='keyword'>int</SPAN> <A CLASS="documented" HREF="#final_newline">final_newline</A> = 16; } <SPAN CLASS="comment">// End namespace boost::iostreams::newline</SPAN> <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#newline_filter">newline_filter</A>; <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#newline_checker">newline_checker</A>; <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#newline_error">newline_error</A>; } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE> <A name="reference"></A> <H2>Reference</H2> <A name="constants"></A> <H3>1. Namespace <CODE>boost::iostreams::newline</CODE></H3> <P>The namespace <CODE>boost::iostreams::newline</CODE> contains integral constants used to configure <CODE>newline_filter</CODE>, <CODE>newline_checker</CODE> and to report errors. The constants have the following interpretations.</P> <TABLE STYLE="margin-left:2em; margin-bottom:2em" BORDER=1 CELLPADDING=4> <TR><TH>Constant</TH><TH>Interpretation</TH></TR> <TR> <TD VALIGN="top"><A NAME="posix"></A><CODE>posix</CODE></TD> <TD> Used to indicate POSIX line-ending conventions. </TD> </TR> <TR> <TD VALIGN="top"><A NAME="dos"></A><CODE>dos</CODE></TD> <TD> Used to indicate DOS line-ending conventions. </TD> </TR> <TR> <TD VALIGN="top"><A NAME="mac"></A><CODE>mac</CODE></TD> <TD> Used to indicate classic Mac line-ending conventions. </TD> </TR> <TR> <TD VALIGN="top"><A NAME="mixed"></A><CODE>mixed</CODE></TD> <TD> Used to describe a document with mixed line endings. </TD> </TR> <TR> <TD VALIGN="top"><A NAME="final_newline"></A><CODE>final_newline</CODE></TD> <TD> Used to indicate that a document ends in a newline sequence. </TD> </TR> </TABLE> <A name="newline_filter"></A> <H3>2. Class <CODE>newline_filter</CODE></H3> <H4>Description</H4> <P> <A HREF="../concepts/dual_use_filter.html">DualUseFilter</A> which converts between the line-ending conventions used by various operating systems. Its sole constructor takes an integral parameter used to specify the target format. </P> <H4>Synopsis</H4> <PRE CLASS="broken_ie"><SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">newline_filter</SPAN> { <SPAN CLASS='keyword'>public:</SPAN> <SPAN CLASS='keyword'>typedef</SPAN> char char_type; <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>[implementation-defined]</SPAN> category; <SPAN CLASS='keyword'>explicit</SPAN> <A CLASS="documented" HREF="#newline_filter_ctor">newline_filter</A>(<SPAN CLASS='keyword'>int</SPAN> target); };</PRE> <A name="newline_filter_ctor"></A> <H4><CODE>newline_filter::newline_filter</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>explicit</SPAN> newline_filter(<SPAN CLASS='keyword'>int</SPAN> target);</PRE> <P>Constructs a newline_filter for converting to the specified format. The parameter target must be <A HREF='#posix'><CODE>newline::posix</CODE></A>, <A HREF='#dos'><CODE>newline::dos</CODE></A> or <A HREF='#mac'><CODE>newline::mac</CODE></A>.</P> <A name="newline_checker"></A> <H3>3. Class <CODE>newline_checker</CODE></H3> <H4>Description</H4> <P> <A HREF="../concepts/dual_use_filter.html">DualUseFilter</A> used to verify that a character sequence conforms to a given line-ending convention. </P> <H4>Synopsis</H4> <PRE CLASS="broken_ie"><SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">newline_checker</SPAN> { <SPAN CLASS='keyword'>public:</SPAN> <SPAN CLASS='keyword'>typedef</SPAN> char char_type; <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>[implementation-defined]</SPAN> category; <SPAN CLASS='keyword'>explicit</SPAN> <A CLASS="documented" HREF="#newline_filter_ctor">newline_checker</A>(<SPAN CLASS='keyword'>int</SPAN> target = <SPAN CLASS='omitted'>default_value</SPAN> ); <SPAN CLASS='keyword'>bool</SPAN> <A CLASS='documented' HREF='#newline_checker_is_posix'>is_posix</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_dos">is_dos</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_mac">is_mac</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_mixed_posix">is_mixed_posix</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_mixed_dos">is_mixed_dos</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_mixed_mac">is_mixed_mac</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_is_mixed">is_mixed</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_checker_has_final_newline">has_final_newline</A>() <SPAN CLASS='keyword'>const</SPAN>; };</PRE> <A name="newline_checker::newline_checker_ctor"></A> <H4><CODE>newline_checker::newline_checker</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>explicit</SPAN> newline_checker(<SPAN CLASS='keyword'>int</SPAN> target = <SPAN CLASS='omitted'>default_value</SPAN> );</PRE> <P>Constructs a newline_checker. If a target is specified, a newline_error will be thrown as soon as a line-ending sequence is encountered which does not conform to the target. The value target must be be <A HREF='#posix'><CODE>newline::posix</CODE></A>, <A HREF='#dos'><CODE>newline::dos</CODE></A> or <A HREF='#mac'><CODE>newline::mac</CODE></A> or the bitwise OR of one of these values with <A HREF='#mac'><CODE>newline::final_newline</CODE></A>.</P> <P><B>Note:</B> If a <CODE>newline_checker</CODE> is being used to perform output, the failure of a character sequence to end with a newline sequence may be discovered only when the newline_checker is <A HREF='../functions/close.html'>closed</A>. There are certain circumstances in which exceptions thrown by <A HREF='../functions/close.html'><CODE>close</CODE></A> are caught and ignored by the Iostreams library. Consequently, when performing output specifying <CODE>newline::final_newline</CODE> as part of <CODE>target</CODE> may have no effect. To check whether a character sequence ends with a newline sequence, call <A HREF='#newline_checker_has_final_newline'><CODE>has_final_newline</CODE></A> after the <CODE>newline_checker</CODE> has been closed. <A name="newline_checker_is_posix"></A> <H4><CODE>newline_checker::is_posix</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_posix() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one POSIX line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_checker_is_dos"></A> <H4><CODE>newline_checker::is_dos</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_dos() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one DOS line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_checker_is_mac"></A> <H4><CODE>newline_checker::is_mac</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mac() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one classic Mac line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_checker_is_mixed_posix"></A> <H4><CODE>newline_checker::is_mixed_posix</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_posix() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one POSIX line-ending sequence.</P> <A name="newline_checker_is_mixed_dos"></A> <H4><CODE>newline_checker::is_mixed_dos</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_dos() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one DOS line-ending sequence.</P> <A name="newline_checker_is_mixed_mac"></A> <H4><CODE>newline_checker::is_mixed_mac</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_mac() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained at least one classic Mac line-ending sequence.</P> <A name="newline_checker_is_mixed"></A> <H4><CODE>newline_checker::is_mixed</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined so far contained line-ending sequences of more than one type.</P> <A name="newline_checker_has_final_newline"></A> <H4><CODE>newline_checker::has_final_newline</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> has_final_newline() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns <CODE>true</CODE> if this <CODE>newline_checker</CODE> has either been closed or has reached end-of-stream, and if the examined character sequence ended with a newline sequence.</P> <A name="newline_error"></A> <H3>4. Class template <CODE>newline_error</CODE></H3> <H4>Description</H4> <P>Used by <A HREF='#newline_checker'><CODE>newline_checker</CODE></A> to report errors.</P> <H4>Synopsis</H4> <PRE CLASS="broken_ie"><SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">newline_error</SPAN> : <SPAN CLASS="keyword">public</SPAN> std::ios_base::failure { <SPAN CLASS='keyword'>public:</SPAN> <SPAN CLASS='keyword'>bool</SPAN> <A CLASS='documented' HREF='#newline_error_is_posix'>is_posix</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_dos">is_dos</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_mac">is_mac</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_mixed_posix">is_mixed_posix</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_mixed_dos">is_mixed_dos</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_mixed_mac">is_mixed_mac</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_is_mixed">is_mixed</A>() <SPAN CLASS='keyword'>const</SPAN>; <SPAN CLASS='keyword'>bool</SPAN> <A CLASS="documented" HREF="#newline_error_has_final_newline">has_final_newline</A>() <SPAN CLASS='keyword'>const</SPAN>; };</PRE> <A name="newline_error_is_posix"></A> <H4><CODE>newline_error::is_posix</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_posix() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one POSIX line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_error_is_dos"></A> <H4><CODE>newline_error::is_dos</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_dos() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one DOS line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_error_is_mac"></A> <H4><CODE>newline_error::is_mac</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mac() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one classic Mac line-ending sequence and no line-ending sequences of any other type.</P> <A name="newline_error_is_mixed_posix"></A> <H4><CODE>newline_error::is_mixed_posix</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_posix() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one POSIX line-ending sequence.</P> <A name="newline_error_is_mixed_dos"></A> <H4><CODE>newline_error::is_mixed_dos</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_dos() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one DOS line-ending sequence.</P> <A name="newline_error_is_mixed_mac"></A> <H4><CODE>newline_error::is_mixed_mac</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed_mac() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained at least one classic Mac line-ending sequence.</P> <A name="newline_error_is_mixed"></A> <H4><CODE>newline_error::is_mixed</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> is_mixed() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns true if the characters examined by the <CODE>newline_checker</CODE> which threw this exception contained line-ending sequences of more than one type.</P> <A name="newline_error_has_final_newline"></A> <H4><CODE>newline_error::has_final_newline</CODE></H4> <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>bool</SPAN> has_final_newline() <SPAN CLASS='keyword'>const</SPAN>;</PRE> <P>Returns <CODE>true</CODE> if the <CODE>newline_checker</CODE> which threw this exception was either closed or had reached end-of-stream and if the examined character sequence ended with a newline sequence.</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. 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