boost_1_45_0/libs/iostreams/doc/classes/grep_filter.html - nest-learning-thermostat/5.0/boost - Git at Google

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <HTML>
 <HEAD>
     <TITLE>Class Template basic_grep_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>basic_grep_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="#installation">Installation</A></DT>
   <DT><A href="#reference">Reference</A></DT>
 </DL>

 <HR>

 <A NAME="description"></A>
 <H2>Description</H2>

 <P>
     The class template <CODE>basic_grep_filter</CODE> filters a character sequence line by line using a regular expression provided at construction, in a manner similar to the command-line utility <i>grep</i> (<A CLASS="bib_ref" HREF="../bibliography.html#grep">[IEEE]</A>). The filter uses regular expressions from the <A HREF="http://www.boost.org/libs/regex" TARGET="_top">Boost Regular Expression Library</A> (<A CLASS="bib_ref" HREF="../bibliography.html#maddock">[Maddock]</A>).
 </P>
 <P>
     By default, the filtered character sequence consists of those lines of the unfilitered sequence that contain a subsequence matching the regular expression. By specifying appropriate options at construction, <CODE>basic_grep_filter</CODE> can be made to pass through only those lines which exactly match the regular expression (as if the option <i>-x</i> had been  passed to the command-line utility) or only those lines that <i>do not</i> contain a match (as if the option <i>-v</i> had been  passed to the command-line utility).
 </P>
 <P>
     A running count of the lines in the filtered character sequence is available via the member function <code><a href="#count">count</a></code>.
 </P>

 <A NAME="headers"></A>
 <H2>Headers</H2>

 <DL class="page-index">
   <DT><A CLASS="header" HREF="../../../../boost/iostreams/filter/grep.hpp"><CODE>&lt;boost/iostreams/filter/grep.hpp&gt;</CODE></A></DT>
 </DL>

 <A NAME="installation"></A>
 <H2>Installation</H2>

 <P>
     The template <CODE>basic_grep_filter</CODE> uses the <A HREF="http://www.boost.org/libs/regex" TARGET="_top">Boost Regular Expression Library</A>, which must be built separately. See <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/install.html" TARGET="_top">here</A> for details.
 </P>

 <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="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/function.hpp" TARGET="_top"><SPAN CLASS="literal">&lt;boost/function.hpp&gt;</SPAN></A>
 <SPAN CLASS="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/regex.hpp" TARGET="_top"><SPAN CLASS="literal">&lt;boost/regex.hpp&gt;</SPAN></A>

 <SPAN CLASS="keyword">namespace</SPAN> grep {

 <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> invert;
 <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> whole_line;

 }

 <SPAN CLASS="keyword">template</SPAN>&lt; <SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Ch</A>,
           <SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Tr</A> = regex_traits&lt;Ch&gt;,
           <SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Alloc</A> = std::allocator&lt;Ch&gt; &gt;
 <SPAN CLASS="keyword">class</SPAN> <A HREF="#template_params" CLASS="documented">basic_grep_filter</A> {
 <SPAN CLASS="keyword">public:</SPAN>
     <A CLASS="documented" HREF="#constructor">basic_grep_filter</A>( <SPAN CLASS="keyword">const</SPAN> basic_regex&lt;Ch, Tr, Alloc&gt;& pattern,
                        regex_constants::match_flag_type flags =
                            regex_constants::match_default,
                        <SPAN CLASS="keyword">int</SPAN> options = <SPAN CLASS="numeric_literal">0</SPAN> );
     <SPAN CLASS="keyword">int</SPAN> <A CLASS="documented" HREF="#count">count</A>() <SPAN CLASS="keyword">const</SPAN>;
 };

 <SPAN CLASS="keyword">typedef</SPAN> basic_grep_filter&lt;<SPAN CLASS="keyword">char</SPAN>&gt;     <SPAN CLASS="defined">grep_filter</SPAN>;
 <SPAN CLASS="keyword">typedef</SPAN> basic_grep_filter&lt;<SPAN CLASS="keyword">wchar_t</SPAN>&gt;  <SPAN CLASS="defined">wgrep_filter</SPAN>;

 } } // End namespace boost::io</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>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>The character type</TD>
     </TR>
     <TR>
         <TD VALIGN="top"><I>Tr</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>The <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_traits.html" TARGET="_top">regular expression traits</A> type</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 character buffers</TD>
     </TR>
 </TABLE>

 <A NAME="constructor"></A>
 <H4><CODE>basic_grep_filter::basic_grep_filter</CODE></H4>

 <PRE CLASS="broken_ie">    <B>basic_grep_filter</B>( <SPAN CLASS="keyword">const</SPAN> basic_regex&lt;Ch, Tr, Alloc&gt;& pattern,
                        regex_constants::match_flag_type flags =
                            regex_constants::match_default,
                        <SPAN CLASS="keyword">int</SPAN> options = <SPAN CLASS="numeric_literal">0</SPAN> );</PRE>

 <P>Constructs a <CODE>basic_grep_filter</CODE> from the given regular expression, match flags, and grep options. The parameters have the following interpretations:</P>

 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
 <TR>
     <TR>
         <TD VALIGN="top"><I>pattern</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>The regular expression to be matched against the stream of unfiltered data</TD>
     </TR>
     <TR>
         <TD VALIGN="top"><I>flags</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>The flags passed to <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_search.html" TARGET="_top">regex_search</A> or <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_match.html" TARGET="_top">regex_match</A> to specify regular expression matching behavior</TD>
     </TR>
     <TR>
         <TD VALIGN="top"><I>options</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>A bitwise OR of zero or more constants from the namespace <CODE>boost::iostreams::grep</CODE>. Currently two constants are recongnized: <CODE>grep::whole_line</CODE> causes the filter to pass through only those lines which exactly match the regular expression, and <CODE>grep::invert</CODE> causes the filter to pass through only those lines that <i>do not</i> contain a match.</TD>
     </TR>
 </TABLE>

 </P>

 <A NAME="count"></A>
 <H4><CODE>basic_grep_filter::count</CODE></H4>

 <A NAME="second_constructor"></A>

 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">int</SPAN> count() <SPAN CLASS="keyword">const</SPAN>;</PRE>

 <P>Returns a running count of the lines passed through from the unfiltered character sequence to the filtered character sequence. The count is reset to zero automatically when the filter begins processing a new character sequence.</P>

 <!-- Begin Footer -->

 <HR>
 <P CLASS="copyright">Revised 28 May 2008</P>

 <P CLASS="copyright">&copy; Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</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>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
	<HTML>
	<HEAD>
	<TITLE>Class Template basic_grep_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>basic_grep_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="#installation">Installation</A></DT>
	<DT><A href="#reference">Reference</A></DT>
	</DL>

	<HR>

	<A NAME="description"></A>
	<H2>Description</H2>

	<P>
	The class template <CODE>basic_grep_filter</CODE> filters a character sequence line by line using a regular expression provided at construction, in a manner similar to the command-line utility <i>grep</i> (<A CLASS="bib_ref" HREF="../bibliography.html#grep">[IEEE]</A>). The filter uses regular expressions from the <A HREF="http://www.boost.org/libs/regex" TARGET="_top">Boost Regular Expression Library</A> (<A CLASS="bib_ref" HREF="../bibliography.html#maddock">[Maddock]</A>).
	</P>
	<P>
	By default, the filtered character sequence consists of those lines of the unfilitered sequence that contain a subsequence matching the regular expression. By specifying appropriate options at construction, <CODE>basic_grep_filter</CODE> can be made to pass through only those lines which exactly match the regular expression (as if the option <i>-x</i> had been passed to the command-line utility) or only those lines that <i>do not</i> contain a match (as if the option <i>-v</i> had been passed to the command-line utility).
	</P>
	<P>
	A running count of the lines in the filtered character sequence is available via the member function <code><a href="#count">count</a></code>.
	</P>

	<A NAME="headers"></A>
	<H2>Headers</H2>

	<DL class="page-index">
	<DT><A CLASS="header" HREF="../../../../boost/iostreams/filter/grep.hpp"><CODE><boost/iostreams/filter/grep.hpp></CODE></A></DT>
	</DL>

	<A NAME="installation"></A>
	<H2>Installation</H2>

	<P>
	The template <CODE>basic_grep_filter</CODE> uses the <A HREF="http://www.boost.org/libs/regex" TARGET="_top">Boost Regular Expression Library</A>, which must be built separately. See <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/install.html" TARGET="_top">here</A> for details.
	</P>

	<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="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/function.hpp" TARGET="_top"><SPAN CLASS="literal"><boost/function.hpp></SPAN></A>
	<SPAN CLASS="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/regex.hpp" TARGET="_top"><SPAN CLASS="literal"><boost/regex.hpp></SPAN></A>

	<SPAN CLASS="keyword">namespace</SPAN> grep {

	<SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> invert;
	<SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> whole_line;

	}

	<SPAN CLASS="keyword">template</SPAN>< <SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Ch</A>,
	<SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Tr</A> = regex_traits<Ch>,
	<SPAN CLASS="keyword">typename</SPAN> <A HREF="#template_params" CLASS="documented">Alloc</A> = std::allocator<Ch> >
	<SPAN CLASS="keyword">class</SPAN> <A HREF="#template_params" CLASS="documented">basic_grep_filter</A> {
	<SPAN CLASS="keyword">public:</SPAN>
	<A CLASS="documented" HREF="#constructor">basic_grep_filter</A>( <SPAN CLASS="keyword">const</SPAN> basic_regex<Ch, Tr, Alloc>& pattern,
	regex_constants::match_flag_type flags =
	regex_constants::match_default,
	<SPAN CLASS="keyword">int</SPAN> options = <SPAN CLASS="numeric_literal">0</SPAN> );
	<SPAN CLASS="keyword">int</SPAN> <A CLASS="documented" HREF="#count">count</A>() <SPAN CLASS="keyword">const</SPAN>;
	};

	<SPAN CLASS="keyword">typedef</SPAN> basic_grep_filter<<SPAN CLASS="keyword">char</SPAN>> <SPAN CLASS="defined">grep_filter</SPAN>;
	<SPAN CLASS="keyword">typedef</SPAN> basic_grep_filter<<SPAN CLASS="keyword">wchar_t</SPAN>> <SPAN CLASS="defined">wgrep_filter</SPAN>;

	} } // End namespace boost::io</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>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>The character type</TD>
	</TR>
	<TR>
	<TD VALIGN="top"><I>Tr</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>The <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_traits.html" TARGET="_top">regular expression traits</A> type</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 character buffers</TD>
	</TR>
	</TABLE>

	<A NAME="constructor"></A>
	<H4><CODE>basic_grep_filter::basic_grep_filter</CODE></H4>

	<PRE CLASS="broken_ie"> <B>basic_grep_filter</B>( <SPAN CLASS="keyword">const</SPAN> basic_regex<Ch, Tr, Alloc>& pattern,
	regex_constants::match_flag_type flags =
	regex_constants::match_default,
	<SPAN CLASS="keyword">int</SPAN> options = <SPAN CLASS="numeric_literal">0</SPAN> );</PRE>

	<P>Constructs a <CODE>basic_grep_filter</CODE> from the given regular expression, match flags, and grep options. The parameters have the following interpretations:</P>

	<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
	<TR>
	<TR>
	<TD VALIGN="top"><I>pattern</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>The regular expression to be matched against the stream of unfiltered data</TD>
	</TR>
	<TR>
	<TD VALIGN="top"><I>flags</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>The flags passed to <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_search.html" TARGET="_top">regex_search</A> or <A HREF="http://www.boost.org/libs/regex/doc/html/boost_regex/ref/regex_match.html" TARGET="_top">regex_match</A> to specify regular expression matching behavior</TD>
	</TR>
	<TR>
	<TD VALIGN="top"><I>options</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>A bitwise OR of zero or more constants from the namespace <CODE>boost::iostreams::grep</CODE>. Currently two constants are recongnized: <CODE>grep::whole_line</CODE> causes the filter to pass through only those lines which exactly match the regular expression, and <CODE>grep::invert</CODE> causes the filter to pass through only those lines that <i>do not</i> contain a match.</TD>
	</TR>
	</TABLE>

	</P>

	<A NAME="count"></A>
	<H4><CODE>basic_grep_filter::count</CODE></H4>

	<A NAME="second_constructor"></A>

	<PRE CLASS="broken_ie"> <SPAN CLASS="keyword">int</SPAN> count() <SPAN CLASS="keyword">const</SPAN>;</PRE>

	<P>Returns a running count of the lines passed through from the unfiltered character sequence to the filtered character sequence. The count is reset to zero automatically when the filter begins processing a new character sequence.</P>

	<!-- Begin Footer -->

	<HR>
	<P CLASS="copyright">Revised 28 May 2008</P>

	<P CLASS="copyright">© Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</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>