ceph/src/boost/libs/iostreams/doc/classes/filter.html

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  12     <H1 CLASS="title">Class Template <CODE>filter</CODE></H1>
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  17 <DL class="page-index">
  18   <DT><A href="#description">Description</A></DT>
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  20   <DT><A href="#reference">Reference</A></DT>
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  24
  25 <A NAME="description"></A>
  26 <H2>Description</H2>
  27
  28 <P>
  29     The class templates <CODE>filter</CODE>, <CODE>wfilter</CODE>, <CODE>multichar_filter</CODE>, <CODE>multichar_wfilter</CODE> and their specializations are provided by the Iostreams library for use as base classes for user-defined <A HREF="../concepts/filter.html">Filters</A>. These base classes supply the member types <CODE>char_type</CODE> and <CODE>category</CODE> used internally by the Iostreams library to classify filters.
  30 </P>
  31 <P>
  32     The supplied <CODE>category</CODE> member is convertible to <A HREF="../guide/traits.html#category_tags"><CODE>closable_tag</CODE></A> and to <A HREF="../guide/traits.html#category_tags"><CODE>localizable_tag</CODE></A>. This allows users to define models of the concepts <A HREF="../concepts/closable.html">Closable</A> and <A HREF="../concepts/closable.html">Localizable</A> simply by providing definitions of member functions <CODE>close</CODE> and <CODE>imbue</CODE>.
  33 </P>
  34
  35 <A NAME="headers"></A>
  36 <H2>Headers</H2>
  37
  38 <DL class="page-index">
  39   <DT><A CLASS="header" HREF="../../../../boost/iostreams/concepts.hpp"><CODE>&lt;boost/iostreams/concepts.hpp&gt;</CODE></A></DT>
  40 </DL>
  41
  42 <A NAME="reference"></A>
  43 <H2>Reference</H2>
  44
  45 <A NAME="synopsis"></A>
  46 <H3>Synopsis</H3>
  47
  48 <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost{ <SPAN CLASS="keyword">namespace</SPAN> iostreams {
  49
  50 <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Mode, <SPAN CLASS="keyword">typename</SPAN> Ch = <SPAN CLASS="keyword">char</SPAN>&gt;
  51 <SPAN CLASS="keyword">struct</SPAN> <A CLASS="documented" HREF="#description">filter</A>;
  52
  53 <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Mode, <SPAN CLASS="keyword">typename</SPAN> Ch = <SPAN CLASS="keyword">wchar_t</SPAN>&gt;
  54 <SPAN CLASS="keyword">struct</SPAN> <SPAN CLASS="defined">wfilter</SPAN> : filter&lt;Mode, Ch&gt; { };
  55
  56 <SPAN CLASS="keyword">typedef</SPAN> filter&lt;input&gt;      input_filter;
  57 <SPAN CLASS="keyword">typedef</SPAN> wfilter&lt;input&gt;     input_wfilter;
  58 <SPAN CLASS="keyword">typedef</SPAN> filter&lt;output&gt;     output_filter;
  59 <SPAN CLASS="keyword">typedef</SPAN> wfilter&lt;output&gt;    output_wfilter;
  60 <SPAN CLASS="keyword">typedef</SPAN> filter&lt;seekable&gt;   seekable_filter;
  61 <SPAN CLASS="keyword">typedef</SPAN> wfilter&lt;seekable&gt;  seekable_wfilter;
  62 <SPAN CLASS="keyword">typedef</SPAN> filter&lt;dual_use&gt;   dual_use_filter;
  63 <SPAN CLASS="keyword">typedef</SPAN> wfilter&lt;dual_use&gt;  dual_use_wfilter;
  64
  65 <SPAN CLASS="keyword"><SPAN CLASS="keyword">template</SPAN></SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Mode, <SPAN CLASS="keyword">typename</SPAN> Ch = <SPAN CLASS="keyword">char</SPAN>&gt;
  66 <SPAN CLASS="keyword">struct</SPAN> <A CLASS="documented" HREF="#multichar_filter">multichar_filter</A> : filter&lt;Mode, Ch&gt; {
  67     <SPAN CLASS="keyword">typedef</SPAN> <A STYLE="text-decoration:none" HREF="#category"><SPAN CLASS="omitted">see below</SPAN></A>  category;
  68 };
  69
  70 <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Mode, <SPAN CLASS="keyword">typename</SPAN> Ch = <SPAN CLASS="keyword">wchar_t</SPAN>&gt;
  71 <SPAN CLASS="keyword">struct</SPAN> <SPAN CLASS="defined">multichar_wfilter</SPAN> : multichar_filter&lt;Mode, Ch&gt; { };
  72
  73 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;input&gt;     multichar_input_filter;
  74 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;input&gt;     multichar_input_wfilter;
  75 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;output&gt;    multichar_output_filter;
  76 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;output&gt;    multichar_output_wfilter;
  77 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;dual_use&gt;  multichar_dual_use_filter;
  78 <SPAN CLASS="keyword">typedef</SPAN> multichar_filter&lt;dual_use&gt;  multichar_dual_use_wfilter;
  79
  80 <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#filter_template_params">Mode</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#filter_template_params">Ch</A> = <SPAN CLASS="keyword">char</SPAN>&gt;
  81 <SPAN CLASS="keyword">struct</SPAN> <A CLASS="documented" HREF="#filter">filter</A> {
  82     <SPAN CLASS="keyword">typedef</SPAN> Ch         char_type;
  83     <SPAN CLASS="keyword">typedef</SPAN> <A STYLE="text-decoration:none" HREF="#category"><SPAN CLASS="omitted">see below</SPAN></A>  category;
  84
  85     <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Device&gt;
  86     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>(Device&amp;);
  87
  88     <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Device&gt;
  89     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>(Device&amp;, std::ios_base::openmode);
  90
  91     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#imbue">imbue</A>(<SPAN CLASS="keyword">const</SPAN> std::locale&amp;);
  92 };
  93
  94 } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE>
  95
  96 <A NAME="filter"></A>
  97 <H3>Class Template <CODE>filter</CODE></H3>
  98
  99 <H4>Description</H4>
 100
 101 <P>Convenience base class for defining <A HREF="../concepts/filter.html">Filters</A></P>
 102
 103 <A NAME="filter_template_params"></A>
 104 <H4>Template parameters</H4>
 105
 106 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
 107     <TR>
 108         <TD VALIGN="top"><I>Mode</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
 109         <TD>A <A HREF="../guide/modes.html#mode_tags">mode tag</A>.</TD>
 110     </TR>
 111     <TR>
 112         <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
 113         <TD>The character type</TD>
 114     </TR>
 115 </TABLE>
 116
 117 <A NAME="category"></A>
 118 <H4><CODE>filter::category</CODE></H4>
 119
 120 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="omitted">see below</SPAN> category;</PRE>
 121
 122 <P>
 123     A category tag convertible to <A HREF="#filter_template_params"><CODE>Mode</CODE></A>, <A HREF="../guide/traits.html#category_tags"><CODE>filter_tag</CODE></A>, <A HREF="../guide/traits.html#category_tags"><CODE>closable_tag</CODE></A> and <A HREF="../guide/traits.html#category_tags"><CODE>localizable_tag</CODE></A>.
 124 </P>
 125
 126 <A NAME="close"></A>
 127 <H4><CODE>filter::close</CODE></H4>
 128
 129 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Device&gt;
 130     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>(Device&amp;);
 131
 132     <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> Device&gt;
 133     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>(Device&amp;, std::ios_base::openmode);</PRE>
 134
 135 <P>
 136     Both overloads are implemented as no-ops. The second is available only if <A HREF="#filter_template_params">Mode</A> is convertible to <A HREF="../guide/modes.html#mode_tags"><CODE>bidirectional</CODE></A>. The first is available only if Mode is <I>not</I> convertible to <A HREF="../guide/modes.html#mode_tags"><CODE>bidirectional</CODE></A>.
 137 </P>
 138 <P>
 139     Required by <A HREF="../concepts/closable.html">Closable</A>.
 140 </P>
 141
 142 <A NAME="imbue"></A>
 143 <H4><CODE>filter::imbue</CODE></H4>
 144 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#imbue">imbue</A>(<SPAN CLASS="keyword">const</SPAN> std::locale&amp;);</PRE>
 145
 146 <P>
 147     Implemented as a no-op. Required by <A HREF="../concepts/localizable.html">Localizable</A>.
 148 </P>
 149
 150 <A NAME="multichar_filter"></A>
 151 <H3>Class Template <CODE>multichar_filter</CODE></H3>
 152
 153 <H4>Description</H4>
 154
 155 <P>Convenience base class for defining <A HREF="../concepts/multi_character.html">Multi-Character Filters</A>. Derived class of <A HREF="#filter"><CODE>filter</CODE></A> whose member type <CODE>category</CODE> is convertible to the template parameter Mode and to <A HREF="../guide/traits.html#category_tags"><CODE>multichar_filter_tag</CODE></A>, <A HREF="../guide/traits.html#category_tags"><CODE>closable_tag</CODE></A> and <A HREF="../guide/traits.html#category_tags"><CODE>localizable_tag</CODE></A>.</P>
 156
 157 <A NAME="multichar_filter_template_params"></A>
 158 <H4>Template parameters</H4>
 159
 160 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
 161     <TR>
 162         <TD VALIGN="top"><I>Mode</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
 163         <TD>A <A HREF="../guide/modes.html#mode_tags">mode tag</A>.</TD>
 164     </TR>
 165     <TR>
 166         <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
 167         <TD>The character type</TD>
 168     </TR>
 169 </TABLE>
 170
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 175 <P CLASS="copyright">&copy; Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</a><br/>&copy; Copyright 2004-2007 <a href="http://www.coderage.com/turkanis/" target="_top">Jonathan Turkanis</a></P>
 176 <P CLASS="copyright">
 177     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>)
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