2004-07-30 01:30:27 +00:00
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>Boost.Range Utility Classes </title>
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<link rel="stylesheet" href="style.css" type="text/css">
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</head>
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<body>
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<table border="0" >
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<tr>
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<td ><img src="cboost.gif" border="0" ></td>
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<td >
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<h1 align="center">Boost.Range utility classes</h1>
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</td>
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</tr>
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</table>
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<p> Having an abstraction that encapsulates a pair of iterators is very
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useful. The standard library uses <code>std::pair</code> in some
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cercumstances, but that class is cumbersome to use because we need to
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specify two template arguments, and for all range algorithm purposes,
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we must enforce the two template arguments to be the same. Moreover,
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<code>std::pair<iterator,iterator></code> is hardly self-documenting
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whereas more domain specific class names are. Therefore these two
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classes are provided:
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<ul>
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2004-07-30 02:56:01 +00:00
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<li>Class <a href=#iter_range><code>iterator_range</code></a>
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<li>Class <a href=#sub_range><code>sub_range</code></a> </ul>
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2004-07-30 01:30:27 +00:00
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</ul>
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The <code>iterator_range</code> class is templated on an iterator and should be
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used whenever super general code is needed. The <code>sub_range</code> class
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is templated on an <a href=range.html#external_range>ExternalRange</a>
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and it is less general, but a bit easier to use since its template argument
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is easier to specify.
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</p>
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2004-07-30 02:56:01 +00:00
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<hr> <a name=iter_range></a> <h1>Class <code>iterator_range</code></h1>
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2004-07-30 01:30:27 +00:00
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The intention of the
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<code>iterator_range</code> class is to encapsulate
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two iterators so they fulfill the <a href=range.html#range>Range</a> concept.
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A few other functions are also provided for convinience.
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<h3>Synopsis</h3>
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<pre>
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namespace boost
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{
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template< class Iterator >
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class iterator_range
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{
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iterator_range(); // not implemented
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public: // Range types
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typedef ... value_type;
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typedef ... difference_type;
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typedef ... size_type;
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typedef Iterator iterator;
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typedef Iterator const_iterator;
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public: // construction, assignment
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template< class Iterator >
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iterator_range( Iterator Begin, Iterator End );
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template< class XRange >
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iterator_range( XRange& r );
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template< class XRange >
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iterator_range( const XRange& r );
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template< class XRange >
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iterator_range& operator=( XRange& r );
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template< class XRange >
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iterator_range& operator=( const XRange& r );
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public: // Range functions
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iterator begin() const;
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iterator end() const;
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size_type size() const;
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bool empty() const;
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public: // convenience
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operator unspecified_bool_type() const;
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void swap( iterator_range& r );
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};
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// stream output
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template< class Iterator, class T, class Traits >
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std::basic_ostream<T,Traits>& operator<<( std::basic_ostream<T,Traits>& Os,
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const iterator_range<Iterator>& r );
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// comparison
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template< class Iterator >
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bool operator==( const iterator_range<Iterator>& l, const iterator_range<Iterator>& r );
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template< class Iterator >
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bool operator!=( const iterator_range<Iterator>& l, const iterator_range<Iterator>& r );
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// external construction
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template< class Iterator >
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iterator_range< Iterator >
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make_iterator_range( Iterator Begin, Iterator End );
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template< class XRange >
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iterator_range< typename iterator_of<XRange>::type >
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make_iterator_range( XRange& r );
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template< class XRange >
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iterator_range< typename const_iterator_of<XRange>::type >
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make_iterator_range( const XRange& r );
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// convenience
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template< class Sequence, class XRange >
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Sequence copy_range( const XRange& r )
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template< class Sequence, class XRange, class Func >
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Sequence transform_range( const XRange& r, Func func );
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} // namespace 'boost'
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</pre>
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<p>
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It is worth noticing that the templated constructors and assignment operators
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allow conversion from <code>iterator_range<iterator></code> to
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<code>iterator_range<const_iterator></code>. If an instance of
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<code>iterator_range</code> is constructed by a client with two iterators, the
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client must ensure that the two iterators delimit a valid closed-open range
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<code>[begin,end)</code>.
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</p>
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<hr> <a name=sub_range></a>
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2004-07-30 02:56:01 +00:00
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<h1>Class <code>sub_range</code></h1>
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2004-07-30 01:30:27 +00:00
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The <code>sub_range</code> class inherits all its functionality
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from the <a href="#iter_range"><code>iterator_range</code></a> class.
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The <code>sub_range</code> class is often easier to use because
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one must specify the <a href="range.html#external_range">ExternalRange</a>
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template argument instead of an iterator.
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<h3>Synopsis</h3>
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<pre>
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namespace boost
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{
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template< class XRange >
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class sub_range : public iterator_range< typename result_iterator_of<XRange>::type >
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{
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public: // construction, assignment
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template< class Iterator >
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sub_range( Iterator Begin, Iterator End );
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template< class XRange2 >
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sub_range( XRange2& r );
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template< class XRange2 >
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sub_range( const Range2& r );
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template< class XRange2 >
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sub_range& operator=( XRange2& r );
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template< class XRange2 >
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sub_range& operator=( const XRange2& r );
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public:
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// rest of interface inherited from iterator_range
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};
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} // namespace 'boost'
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</pre>
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<hr>
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<p>
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(C) Copyright Thorsten Ottosen 2003-2004
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</p>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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</body>
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</html>
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