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Applied use of iterator-category to specialized adapters

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[SVN r21745]
This commit is contained in:
Dave Abrahams
2004-01-15 00:01:33 +00:00
parent 33f630beca
commit c3fd7076c1
11 changed files with 290 additions and 253 deletions
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32
doc/counting_iterator.html
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@ -89,21 +89,25 @@ class counting_iterator
Incrementable m_inc; // exposition
};
</pre>
<p>If the <tt class="literal"><span class="pre">Difference</span></tt> argument is <tt class="literal"><span class="pre">use_default</span></tt> then the
<tt class="literal"><span class="pre">difference_type</span></tt> member is an unspecified signed integral
<p>If the <tt class="literal"><span class="pre">Difference</span></tt> argument is <tt class="literal"><span class="pre">use_default</span></tt> then
<tt class="literal"><span class="pre">difference_type</span></tt> is an unspecified signed integral
type. Otherwise <tt class="literal"><span class="pre">difference_type</span></tt> is <tt class="literal"><span class="pre">Difference</span></tt>.</p>
<p>If <tt class="literal"><span class="pre">CategoryOrTraversal</span></tt> is not <tt class="literal"><span class="pre">use_default</span></tt> then the member
<tt class="literal"><span class="pre">iterator_category</span></tt> is <tt class="literal"><span class="pre">CategoryOrTraversal</span></tt>. Otherwise, if
<tt class="literal"><span class="pre">numeric_limits&lt;Incrementable&gt;::is_specialized</span></tt>, then
<tt class="literal"><span class="pre">iterator_category</span></tt> is a
<tt class="literal"><span class="pre">facade_iterator_category(random_access_traversal_tag,</span> <span class="pre">Incrementable,</span> <span class="pre">const</span> <span class="pre">Incrementable&amp;)</span></tt>.
Otherwise, <tt class="literal"><span class="pre">iterator_category</span></tt> is
<tt class="literal"><span class="pre">facade_iterator_category(iterator_traversal&lt;Incrementable&gt;::type,</span> <span class="pre">Incrementable,</span> <span class="pre">const</span> <span class="pre">Incrementable&amp;)</span></tt>.</p>
<dl>
<dt>[<em>Note:</em> implementers are encouraged to provide an implementation of</dt>
<dd><tt class="literal"><span class="pre">operator-</span></tt> and the default <tt class="literal"><span class="pre">difference_type</span></tt> that avoids overflows in
the cases when the <tt class="literal"><span class="pre">Incrementable</span></tt> type is a numeric type.]</dd>
</dl>
<p><tt class="literal"><span class="pre">iterator_category</span></tt> is determined according to the following
algorithm:</p>
<pre class="literal-block">
if (CategoryOrTraversal is not use_default)
return CategoryOrTraversal
else if (numeric_limits&lt;Incrementable&gt;::is_specialized)
return <a class="reference" href="iterator_facade.html#iterator-category"><em>iterator-category</em></a>(
random_access_traversal_tag, Incrementable, const Incrementable&amp;)
else
return <a class="reference" href="iterator_facade.html#iterator-category"><em>iterator-category</em></a>(
iterator_traversal&lt;Incrementable&gt;::type,
Incrementable, const Incrementable&amp;)
</pre>
<p>[<em>Note:</em> implementers are encouraged to provide an implementation
of <tt class="literal"><span class="pre">operator-</span></tt> and a default <tt class="literal"><span class="pre">difference_type</span></tt> that avoid
overflows when <tt class="literal"><span class="pre">Incrementable</span></tt> is a numeric type.]</p>
</div>
<div class="section" id="counting-iterator-requirements">
<h1><a class="toc-backref" href="#id3" name="counting-iterator-requirements"><tt class="literal"><span class="pre">counting_iterator</span></tt> requirements</a></h1>