[ceph.git] / ceph / src / boost / libs / iterator / doc / function_output_iterator.html

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<title>Function Output Iterator</title>
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
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<div class="document" id="function-output-iterator">
<h1 class="title">Function Output Iterator</h1>
<table class="docinfo" frame="void" rules="none">
<col class="docinfo-name" />
<col class="docinfo-content" />
<tbody valign="top">
<tr><th class="docinfo-name">Author:</th>
<td>David Abrahams, Jeremy Siek, Thomas Witt</td></tr>
<tr><th class="docinfo-name">Contact:</th>
<td><a class="first reference external" href="mailto:dave&#64;boost-consulting.com">dave&#64;boost-consulting.com</a>, <a class="reference external" href="mailto:jsiek&#64;osl.iu.edu">jsiek&#64;osl.iu.edu</a>, <a class="last reference external" href="mailto:witt&#64;ive.uni-hannover.de">witt&#64;ive.uni-hannover.de</a></td></tr>
<tr><th class="docinfo-name">Organization:</th>
<td><a class="first reference external" href="http://www.boost-consulting.com">Boost Consulting</a>, Indiana University <a class="reference external" href="http://www.osl.iu.edu">Open Systems
Lab</a>, University of Hanover <a class="last reference external" href="http://www.ive.uni-hannover.de">Institute for Transport
Railway Operation and Construction</a></td></tr>
<tr><th class="docinfo-name">Date:</th>
<td>2006-09-11</td></tr>
<tr><th class="docinfo-name">Copyright:</th>
<td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003.</td></tr>
</tbody>
</table>
<!-- Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">abstract:</th><td class="field-body"><!-- Copyright David Abrahams 2006. Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
The function output iterator adaptor makes it easier to create custom
output iterators. The adaptor takes a unary function and creates a
model of Output Iterator. Each item assigned to the output iterator is
passed as an argument to the unary function.  The motivation for this
iterator is that creating a conforming output iterator is non-trivial,
particularly because the proper implementation usually requires a
proxy object.</td>
</tr>
</tbody>
</table>
<div class="contents topic" id="table-of-contents">
<p class="topic-title first">Table of Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#header" id="id1">Header</a></li>
<li><a class="reference internal" href="#function-output-iterator-requirements" id="id2"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> requirements</a></li>
<li><a class="reference internal" href="#function-output-iterator-models" id="id3"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> models</a></li>
<li><a class="reference internal" href="#function-output-iterator-operations" id="id4"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> operations</a></li>
<li><a class="reference internal" href="#example" id="id5">Example</a></li>
</ul>
</div>
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
<div class="section" id="header">
<h1><a class="toc-backref" href="#id1">Header</a></h1>
<pre class="literal-block">
#include &lt;boost/function_output_iterator.hpp&gt;
</pre>
<pre class="literal-block">
template &lt;class UnaryFunction&gt;
class function_output_iterator {
public:
  typedef std::output_iterator_tag iterator_category;
  typedef void                     value_type;
  typedef void                     difference_type;
  typedef void                     pointer;
  typedef void                     reference;

  explicit function_output_iterator();

  explicit function_output_iterator(const UnaryFunction&amp; f);

  /* see below */ operator*();
  function_output_iterator&amp; operator++();
  function_output_iterator&amp; operator++(int);
private:
  UnaryFunction m_f;     // exposition only
};
</pre>
</div>
<div class="section" id="function-output-iterator-requirements">
<h1><a class="toc-backref" href="#id2"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> requirements</a></h1>
<p><tt class="docutils literal"><span class="pre">UnaryFunction</span></tt> must be Assignable and Copy Constructible.</p>
</div>
<div class="section" id="function-output-iterator-models">
<h1><a class="toc-backref" href="#id3"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> models</a></h1>
<p><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> is a model of the Writable and
Incrementable Iterator concepts.</p>
</div>
<div class="section" id="function-output-iterator-operations">
<h1><a class="toc-backref" href="#id4"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> operations</a></h1>
<p><tt class="docutils literal"><span class="pre">explicit</span> <span class="pre">function_output_iterator(const</span> <span class="pre">UnaryFunction&amp;</span> <span class="pre">f</span> <span class="pre">=</span> <span class="pre">UnaryFunction());</span></tt></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Effects:</th><td class="field-body">Constructs an instance of <tt class="docutils literal"><span class="pre">function_output_iterator</span></tt>
with <tt class="docutils literal"><span class="pre">m_f</span></tt> constructed from <tt class="docutils literal"><span class="pre">f</span></tt>.</td>
</tr>
</tbody>
</table>
<p><tt class="docutils literal"><span class="pre">operator*();</span></tt></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An object <tt class="docutils literal"><span class="pre">r</span></tt> of unspecified type such that <tt class="docutils literal"><span class="pre">r</span> <span class="pre">=</span> <span class="pre">t</span></tt>
is equivalent to <tt class="docutils literal"><span class="pre">m_f(t)</span></tt> for all <tt class="docutils literal"><span class="pre">t</span></tt>.</td>
</tr>
</tbody>
</table>
<p><tt class="docutils literal"><span class="pre">function_output_iterator&amp;</span> <span class="pre">operator++();</span></tt></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
</tr>
</tbody>
</table>
<p><tt class="docutils literal"><span class="pre">function_output_iterator&amp;</span> <span class="pre">operator++(int);</span></tt></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
</tr>
</tbody>
</table>
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
</div>
<div class="section" id="example">
<h1><a class="toc-backref" href="#id5">Example</a></h1>
<pre class="literal-block">
struct string_appender
{
    string_appender(std::string&amp; s)
        : m_str(&amp;s)
    {}

    void operator()(const std::string&amp; x) const
    {
        *m_str += x;
    }

    std::string* m_str;
};

int main(int, char*[])
{
  std::vector&lt;std::string&gt; x;
  x.push_back(&quot;hello&quot;);
  x.push_back(&quot; &quot;);
  x.push_back(&quot;world&quot;);
  x.push_back(&quot;!&quot;);

  std::string s = &quot;&quot;;
  std::copy(x.begin(), x.end(),
            boost::make_function_output_iterator(string_appender(s)));

  std::cout &lt;&lt; s &lt;&lt; std::endl;

  return 0;
}
</pre>
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Commit	Line	Data
7c673cae FG	1	<?xml version="1.0" encoding="utf-8" ?>
	2	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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	4	<head>
	5	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	6	<meta name="generator" content="Docutils 0.5: http://docutils.sourceforge.net/" />
	7	<title>Function Output Iterator</title>
	8	<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
	9	<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
	10	<meta name="date" content="2006-09-11" />
	11	<meta name="copyright" content="Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003." />
	12	<link rel="stylesheet" href="../../../rst.css" type="text/css" />
	13	</head>
	14	<body>
	15	<div class="document" id="function-output-iterator">
	16	<h1 class="title">Function Output Iterator</h1>
	17	<table class="docinfo" frame="void" rules="none">
	18	<col class="docinfo-name" />
	19	<col class="docinfo-content" />
	20	<tbody valign="top">
	21	<tr><th class="docinfo-name">Author:</th>
	22	<td>David Abrahams, Jeremy Siek, Thomas Witt</td></tr>
	23	<tr><th class="docinfo-name">Contact:</th>
	24	<td><a class="first reference external" href="mailto:dave@boost-consulting.com">dave@boost-consulting.com</a>, <a class="reference external" href="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</a>, <a class="last reference external" href="mailto:witt@ive.uni-hannover.de">witt@ive.uni-hannover.de</a></td></tr>
	25	<tr><th class="docinfo-name">Organization:</th>
	26	<td><a class="first reference external" href="http://www.boost-consulting.com">Boost Consulting</a>, Indiana University <a class="reference external" href="http://www.osl.iu.edu">Open Systems
	27	Lab</a>, University of Hanover <a class="last reference external" href="http://www.ive.uni-hannover.de">Institute for Transport
	28	Railway Operation and Construction</a></td></tr>
	29	<tr><th class="docinfo-name">Date:</th>
	30	<td>2006-09-11</td></tr>
	31	<tr><th class="docinfo-name">Copyright:</th>
	32	<td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003.</td></tr>
	33	</tbody>
	34	</table>
	35	<!-- Distributed under the Boost -->
	36	<!-- Software License, Version 1.0. (See accompanying -->
	37	<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
	38	<table class="docutils field-list" frame="void" rules="none">
	39	<col class="field-name" />
	40	<col class="field-body" />
	41	<tbody valign="top">
	42	<tr class="field"><th class="field-name">abstract:</th><td class="field-body"><!-- Copyright David Abrahams 2006. Distributed under the Boost -->
	43	<!-- Software License, Version 1.0. (See accompanying -->
	44	<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
	45	The function output iterator adaptor makes it easier to create custom
	46	output iterators. The adaptor takes a unary function and creates a
	47	model of Output Iterator. Each item assigned to the output iterator is
	48	passed as an argument to the unary function. The motivation for this
	49	iterator is that creating a conforming output iterator is non-trivial,
	50	particularly because the proper implementation usually requires a
	51	proxy object.</td>
	52	</tr>
	53	</tbody>
	54	</table>
	55	<div class="contents topic" id="table-of-contents">
	56	<p class="topic-title first">Table of Contents</p>
	57	<ul class="simple">
	58	<li><a class="reference internal" href="#header" id="id1">Header</a></li>
	59	<li><a class="reference internal" href="#function-output-iterator-requirements" id="id2"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> requirements</a></li>
	60	<li><a class="reference internal" href="#function-output-iterator-models" id="id3"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> models</a></li>
	61	<li><a class="reference internal" href="#function-output-iterator-operations" id="id4"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> operations</a></li>
	62	<li><a class="reference internal" href="#example" id="id5">Example</a></li>
	63	</ul>
	64	</div>
65	<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
66	<!-- Software License, Version 1.0. (See accompanying -->
67	<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
68	<div class="section" id="header">
69	<h1><a class="toc-backref" href="#id1">Header</a></h1>
70	<pre class="literal-block">
71	#include <boost/function_output_iterator.hpp>
72	</pre>
73	<pre class="literal-block">
74	template <class UnaryFunction>
75	class function_output_iterator {
76	public:
77	typedef std::output_iterator_tag iterator_category;
78	typedef void value_type;
79	typedef void difference_type;
80	typedef void pointer;
81	typedef void reference;
82
83	explicit function_output_iterator();
84
85	explicit function_output_iterator(const UnaryFunction& f);
86
87	/* see below / operator();
88	function_output_iterator& operator++();
89	function_output_iterator& operator++(int);
90	private:
91	UnaryFunction m_f; // exposition only
92	};
93	</pre>
94	</div>
95	<div class="section" id="function-output-iterator-requirements">
96	<h1><a class="toc-backref" href="#id2"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> requirements</a></h1>
97	<p><tt class="docutils literal"><span class="pre">UnaryFunction</span></tt> must be Assignable and Copy Constructible.</p>
98	</div>
99	<div class="section" id="function-output-iterator-models">
100	<h1><a class="toc-backref" href="#id3"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> models</a></h1>
101	<p><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> is a model of the Writable and
102	Incrementable Iterator concepts.</p>
103	</div>
104	<div class="section" id="function-output-iterator-operations">
105	<h1><a class="toc-backref" href="#id4"><tt class="docutils literal"><span class="pre">function_output_iterator</span></tt> operations</a></h1>
106	<p><tt class="docutils literal"><span class="pre">explicit</span> <span class="pre">function_output_iterator(const</span> <span class="pre">UnaryFunction&</span> <span class="pre">f</span> <span class="pre">=</span> <span class="pre">UnaryFunction());</span></tt></p>
107	<table class="docutils field-list" frame="void" rules="none">
108	<col class="field-name" />
109	<col class="field-body" />
110	<tbody valign="top">
111	<tr class="field"><th class="field-name">Effects:</th><td class="field-body">Constructs an instance of <tt class="docutils literal"><span class="pre">function_output_iterator</span></tt>
112	with <tt class="docutils literal"><span class="pre">m_f</span></tt> constructed from <tt class="docutils literal"><span class="pre">f</span></tt>.</td>
113	</tr>
114	</tbody>
115	</table>
116	<p><tt class="docutils literal"><span class="pre">operator*();</span></tt></p>
117	<table class="docutils field-list" frame="void" rules="none">
118	<col class="field-name" />
119	<col class="field-body" />
120	<tbody valign="top">
121	<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An object <tt class="docutils literal"><span class="pre">r</span></tt> of unspecified type such that <tt class="docutils literal"><span class="pre">r</span> <span class="pre">=</span> <span class="pre">t</span></tt>
122	is equivalent to <tt class="docutils literal"><span class="pre">m_f(t)</span></tt> for all <tt class="docutils literal"><span class="pre">t</span></tt>.</td>
123	</tr>
124	</tbody>
125	</table>
126	<p><tt class="docutils literal"><span class="pre">function_output_iterator&</span> <span class="pre">operator++();</span></tt></p>
127	<table class="docutils field-list" frame="void" rules="none">
128	<col class="field-name" />
129	<col class="field-body" />
130	<tbody valign="top">
131	<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
132	</tr>
133	</tbody>
134	</table>
135	<p><tt class="docutils literal"><span class="pre">function_output_iterator&</span> <span class="pre">operator++(int);</span></tt></p>
136	<table class="docutils field-list" frame="void" rules="none">
137	<col class="field-name" />
138	<col class="field-body" />
139	<tbody valign="top">
140	<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
141	</tr>
142	</tbody>
143	</table>
144	<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
145	<!-- Software License, Version 1.0. (See accompanying -->
146	<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
147	</div>
148	<div class="section" id="example">
149	<h1><a class="toc-backref" href="#id5">Example</a></h1>
150	<pre class="literal-block">
151	struct string_appender
152	{
153	string_appender(std::string& s)
154	: m_str(&s)
155	{}
156
157	void operator()(const std::string& x) const
158	{
159	*m_str += x;
160	}
161
162	std::string* m_str;
163	};
164
165	int main(int, char*[])
166	{
167	std::vector<std::string> x;
168	x.push_back("hello");
169	x.push_back(" ");
170	x.push_back("world");
171	x.push_back("!");
172
173	std::string s = "";
174	std::copy(x.begin(), x.end(),
175	boost::make_function_output_iterator(string_appender(s)));
176
177	std::cout << s << std::endl;
178
179	return 0;
180	}
181	</pre>
182	</div>
183	</div>
184	<div class="footer">
185	<hr class="footer" />
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187	Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
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