iterator/doc/iterator_adaptor_ref.html
Jeremy Siek 506517191c new files for iterator concepts
[SVN r22004]
2004-01-27 17:03:46 +00:00

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<!-- Version 1.4 of this ReStructuredText document corresponds to
n1530_, the paper accepted by the LWG for TR1. -->
<!-- Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All
rights reserved. -->
<pre class="literal-block">
template &lt;
class Derived
, class Base
, class Value = use_default
, class CategoryOrTraversal = use_default
, class Reference = use_default
, class Difference = use_default
&gt;
class iterator_adaptor
: public iterator_facade&lt;Derived, <em>V</em>, <em>C</em>, <em>R</em>, <em>D</em>&gt; // see <a class="reference" href="#base-parameters">details</a>
{
friend class iterator_core_access;
public:
iterator_adaptor();
explicit iterator_adaptor(Base iter);
Base base() const;
protected:
Base const&amp; base_reference() const;
Base&amp; base_reference();
private: // Core iterator interface for iterator_facade.
typename iterator_adaptor::reference dereference() const;
template &lt;
class OtherDerived, class OtherIterator, class V, class C, class R, class D
&gt;
bool equal(iterator_adaptor&lt;OtherDerived, OtherIterator, V, C, R, D&gt; const&amp; x) const;
void advance(typename iterator_adaptor::difference_type n);
void increment();
void decrement();
template &lt;
class OtherDerived, class OtherIterator, class V, class C, class R, class D
&gt;
typename iterator_adaptor::difference_type distance_to(
iterator_adaptor&lt;OtherDerived, OtherIterator, V, C, R, D&gt; const&amp; y) const;
private:
Base m_iterator; // exposition only
};
</pre>
<a class="target" id="base-parameters" name="base-parameters"></a><div class="section" id="iterator-adaptor-base-class-parameters">
<h1><a name="iterator-adaptor-base-class-parameters"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> base class parameters</a></h1>
<p>The <em>V</em>, <em>C</em>, <em>R</em>, and <em>D</em> parameters of the <tt class="literal"><span class="pre">iterator_facade</span></tt>
used as a base class in the summary of <tt class="literal"><span class="pre">iterator_adaptor</span></tt>
above are defined as follows:</p>
<pre class="literal-block">
<em>V</em> = if (Value is use_default)
return iterator_traits&lt;Base&gt;::value_type
else
return Value
<em>C</em> = if (CategoryOrTraversal is use_default)
return iterator_traversal&lt;Base&gt;::type
else
return CategoryOrTraversal
<em>R</em> = if (Reference is use_default)
if (Value is use_default)
return iterator_traits&lt;Base&gt;::reference
else
return Value&amp;
else
return Reference
<em>D</em> = if (Difference is use_default)
return iterator_traits&lt;Base&gt;::difference_type
else
return Difference
</pre>
</div>
<div class="section" id="iterator-adaptor-usage">
<h1><a name="iterator-adaptor-usage"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> usage</a></h1>
<p>The <tt class="literal"><span class="pre">Derived</span></tt> template parameter must be a publicly derived from
<tt class="literal"><span class="pre">iterator_adaptor</span></tt>. In order for <tt class="literal"><span class="pre">Derived</span></tt> to model the
iterator concepts corresponding to
<tt class="literal"><span class="pre">iterator_traits&lt;Derived&gt;::iterator_category</span></tt>, the expressions
involving <tt class="literal"><span class="pre">m_iterator</span></tt> in the specifications of those private
member functions of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> that may be called by
<tt class="literal"><span class="pre">iterator_facade&lt;Derived,</span> <span class="pre">V,</span> <span class="pre">C,</span> <span class="pre">R,</span> <span class="pre">D&gt;</span></tt>
in evaluating any valid expression involving <tt class="literal"><span class="pre">Derived</span></tt>
in those concepts' requirements.</p>
</div>
<div class="section" id="iterator-adaptor-public-operations">
<h1><a name="iterator-adaptor-public-operations"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> public operations</a></h1>
<p><tt class="literal"><span class="pre">iterator_adaptor();</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body">The <tt class="literal"><span class="pre">Base</span></tt> type must be Default Constructible.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> with
<tt class="literal"><span class="pre">m_iterator</span></tt> default constructed.</td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">explicit</span> <span class="pre">iterator_adaptor(Base</span> <span class="pre">iter);</span></tt></p>
<table class="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 instance of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> with
<tt class="literal"><span class="pre">m_iterator</span></tt> copy constructed from <tt class="literal"><span class="pre">iter</span></tt>.</td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">Base</span> <span class="pre">base()</span> <span class="pre">const;</span></tt></p>
<table class="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="literal"><span class="pre">m_iterator</span></tt></td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="iterator-adaptor-protected-member-functions">
<h1><a name="iterator-adaptor-protected-member-functions"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> protected member functions</a></h1>
<p><tt class="literal"><span class="pre">Base</span> <span class="pre">const&amp;</span> <span class="pre">base_reference()</span> <span class="pre">const;</span></tt></p>
<table class="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">A const reference to <tt class="literal"><span class="pre">m_iterator</span></tt>.</td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">Base&amp;</span> <span class="pre">base_reference();</span></tt></p>
<table class="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">A non-const reference to <tt class="literal"><span class="pre">m_iterator</span></tt>.</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="iterator-adaptor-private-member-functions">
<h1><a name="iterator-adaptor-private-member-functions"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> private member functions</a></h1>
<p><tt class="literal"><span class="pre">typename</span> <span class="pre">iterator_adaptor::reference</span> <span class="pre">dereference()</span> <span class="pre">const;</span></tt></p>
<table class="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="literal"><span class="pre">*m_iterator</span></tt></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template &lt;
class OtherDerived, class OtherIterator, class V, class C, class R, class D
&gt;
bool equal(iterator_adaptor&lt;OtherDerived, OtherIterator, V, C, R, D&gt; const&amp; x) const;
</pre>
<table class="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="literal"><span class="pre">m_iterator</span> <span class="pre">==</span> <span class="pre">x.base()</span></tt></td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">void</span> <span class="pre">advance(typename</span> <span class="pre">iterator_adaptor::difference_type</span> <span class="pre">n);</span></tt></p>
<table class="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"><tt class="literal"><span class="pre">m_iterator</span> <span class="pre">+=</span> <span class="pre">n;</span></tt></td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">void</span> <span class="pre">increment();</span></tt></p>
<table class="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"><tt class="literal"><span class="pre">++m_iterator;</span></tt></td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">void</span> <span class="pre">decrement();</span></tt></p>
<table class="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"><tt class="literal"><span class="pre">--m_iterator;</span></tt></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template &lt;
class OtherDerived, class OtherIterator, class V, class C, class R, class D
&gt;
typename iterator_adaptor::difference_type distance_to(
iterator_adaptor&lt;OtherDerived, OtherIterator, V, C, R, D&gt; const&amp; y) const;
</pre>
<table class="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="literal"><span class="pre">y.base()</span> <span class="pre">-</span> <span class="pre">m_iterator</span></tt></td>
</tr>
</tbody>
</table>
</div>
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