[29] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
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| 2 | <HTML> |
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| 3 | <HEAD> |
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| 4 | <TITLE>Class Template aggregate_filter</TITLE> |
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| 5 | <LINK REL="stylesheet" HREF="../../../../boost.css"> |
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| 6 | <LINK REL="stylesheet" HREF="../theme/iostreams.css"> |
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| 7 | </HEAD> |
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| 8 | <BODY> |
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| 9 | |
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| 10 | <!-- Begin Banner --> |
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| 11 | |
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| 12 | <H1 CLASS="title">Class Template <CODE>aggregate_filter</CODE></H1> |
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| 13 | <HR CLASS="banner"> |
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| 14 | |
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| 15 | <!-- End Banner --> |
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| 16 | |
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| 17 | <DL class="page-index"> |
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| 18 | <DT><A href="#description">Description</A></DT> |
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| 19 | <DT><A href="#headers">Headers</A></DT> |
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| 20 | <DT><A href="#reference">Reference</A></DT> |
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| 21 | <DT><A href="#examples">Examples</A></DT> |
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| 22 | </DL> |
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| 23 | |
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| 24 | <HR> |
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| 25 | |
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| 26 | <A NAME="description"></A> |
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| 27 | <H2>Description</H2> |
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| 28 | |
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| 29 | <P> |
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| 30 | The class template <CODE>aggregate_filter</CODE> is a <A HREF='../concepts/dual_use_filter.html'>DualUseFilter</A> for use as a base class by Filters which filter an entire character sequence at once. Because a <CODE>aggregate_filter</CODE> must read an entire character sequence into memory before it begins to filter, it is not suitable in low-memory situations or for processing character sequences which have no natural end, such as stock tickers. Because of these limitations, <CODE>aggregate_filter</CODE> is best used as an aid to those learning to use the Iostreams library. |
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| 31 | </P> |
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| 32 | <P> |
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| 33 | When used as an <A HREF="../concepts/input_filter.html">InputFilter</A>, an instance of <CODE>aggregate_filter</CODE> reads to the end of the stream as soon as input is commenced. The entire contents of the stream are filtered using the <CODE>private virtual</CODE> function <A HREF="#do_filter"><CODE>do_filter</CODE></A>. The filtered data is stored and used to satisfy all future requests for input until the end of the filtered data is reached. |
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| 34 | </P> |
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| 35 | <P> |
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| 36 | When used as an <A HREF="../concepts/output_filter.html">OutputFilter</A>, an instance of <CODE>aggregate_filter</CODE> stores all data written to it without passing it downstream. When the stream is closed, the entire contents of the stream are filtered using <A HREF="#do_filter"><CODE>do_filter</CODE></A>. The filtered data is then written, all at once, to the next downstream Filter or Device. |
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| 37 | </P> |
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| 38 | |
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| 39 | <A NAME="headers"></A> |
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| 40 | <H2>Headers</H2> |
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| 41 | |
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| 42 | <DL class="page-index"> |
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| 43 | <DT><A CLASS="header" HREF="../../../../boost/iostreams/filter/aggregate.hpp"><CODE><boost/iostreams/filter/aggregate.hpp></CODE></A></DT> |
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| 44 | </DL> |
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| 45 | |
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| 46 | <A NAME="reference"></A> |
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| 47 | <H2>Reference</H2> |
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| 48 | |
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| 49 | <H4>Synopsis</H4> |
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| 50 | |
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| 51 | <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams { |
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| 52 | |
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| 53 | <SPAN CLASS="preprocessor">#include</SPAN> <SPAN CLASS="literal"><vector></SPAN> |
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| 54 | |
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| 55 | <SPAN CLASS="keyword"><SPAN CLASS="keyword">template</SPAN></SPAN>< <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Ch</A>, |
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| 56 | <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Tr</A> = std::char_traits<Ch>, |
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| 57 | <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Alloc</A> = std::allocator<Ch> > |
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| 58 | <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">aggregate_filter</A> { |
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| 59 | <SPAN CLASS="keyword">public</SPAN>: |
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| 60 | <SPAN CLASS="keyword">typedef</SPAN> Ch char_type; |
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| 61 | <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="omitted">implementation-defined</SPAN> category; |
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| 62 | <SPAN CLASS="keyword">typedef</SPAN> std::vector<Char, Alloc> vector_type; |
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| 63 | <SPAN CLASS="keyword">virtual</SPAN> ~aggregate_filter(); |
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| 64 | <SPAN CLASS="omitted">...</SPAN> |
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| 65 | <SPAN CLASS="keyword">private</SPAN>: |
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| 66 | <SPAN CLASS="keyword">virtual</SPAN> <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#do_filter">do_filter</A>(<SPAN CLASS="keyword">const</SPAN> vector_type& src, vector_type& dest) = 0; |
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| 67 | }; |
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| 68 | |
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| 69 | } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE> |
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| 70 | |
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| 71 | <A NAME="template_params"></A> |
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| 72 | <H4>Template parameters</H4> |
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| 73 | |
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| 74 | <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2> |
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| 75 | <TR> |
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| 76 | <TR> |
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| 77 | <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> |
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| 78 | <TD>The character type</TD> |
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| 79 | </TR> |
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| 80 | <TR> |
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| 81 | <TD VALIGN="top"><I>Tr</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> |
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| 82 | <TD>The traits type</TD> |
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| 83 | </TR> |
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| 84 | <TR> |
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| 85 | <TD VALIGN="top"><I>Alloc</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> |
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| 86 | <TD>A standard library allocator type (<A CLASS="bib_ref" HREF="../bibliography.html#iso">[ISO]</A>, 20.1.5), used to instantiate <CODE>std::vector</CODE></TD> |
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| 87 | </TR> |
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| 88 | </TABLE> |
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| 89 | |
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| 90 | <A NAME="do_filter"></A> |
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| 91 | <H4><CODE>aggregate_filter::do_filter</CODE></H4> |
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| 92 | |
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| 93 | <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">virtual</SPAN> <SPAN CLASS="keyword">void</SPAN> <B>do_filter</B>(<SPAN CLASS="keyword">const</SPAN> vector_type& src, vector_type& dest) = 0;</PRE> |
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| 94 | |
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| 95 | <P>Reads unflitered characters from <CODE>src</CODE> and appends filtered characters to <CODE>dest</CODE>, returning after all the characters in <CODE>src</CODE> have been consumed.</P> |
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| 96 | |
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| 97 | <A NAME="examples"></A> |
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| 98 | <H2>Examples</H2> |
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| 99 | |
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| 100 | <P>For example uses of <CODE>aggregate_filter</CODE>, see the headers <A CLASS="header" HREF="../../../../boost/iostreams/filter/regex.hpp"><CODE><boost/iostreams/filter/regex.hpp></CODE></A> and <A CLASS="header" HREF="../../../../boost/iostreams/filter/stdio.hpp"><CODE><boost/iostreams/filter/stdio.hpp></CODE></A>.</P> |
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| 101 | |
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| 102 | <!-- Begin Footer --> |
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| 103 | |
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| 104 | <HR> |
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| 105 | <P CLASS="copyright">Revised |
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| 106 | <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan --> |
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| 107 | 20 May, 2004 |
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| 108 | <!--webbot bot="Timestamp" endspan i-checksum="38504" --> |
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| 109 | </P> |
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| 110 | |
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| 111 | <P CLASS="copyright">© Copyright <A HREF="http://www.kangaroologic.com" TARGET="_top">Jonathan Turkanis</A>, 2004</P> |
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| 112 | <P CLASS="copyright"> |
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| 113 | 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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| 114 | </P> |
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| 115 | |
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| 116 | <!-- End Footer --> |
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| 117 | |
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| 118 | </BODY> |
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