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4 | <TITLE>Class Template aggregate_filter</TITLE> |
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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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