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// Boost.Range library
//
// Copyright Thorsten Ottosen 2003-2008. Use, modification and
// distribution is subject to 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)
//
// For more information, see http://www.boost.org/libs/range/
//
#include <boost/range.hpp>
#include <iterator> // for std::iterator_traits, std::distance()
namespace Foo
{
//
// Our sample UDT. A 'Pair'
// will work as a range when the stored
// elements are iterators.
//
template< class T >
struct Pair
{
T first, last;
};
} // namespace 'Foo'
namespace boost
{
//
// Specialize metafunctions. We must include the range.hpp header.
// We must open the 'boost' namespace.
//
/*
template< class T >
struct range_value< Foo::Pair<T> >
{
typedef typename std::iterator_traits<T>::value_type type;
};
*/
template< class T >
struct range_iterator< Foo::Pair<T> >
{
typedef T type;
};
template< class T >
struct range_const_iterator< Foo::Pair<T> >
{
//
// Remark: this is defined similar to 'range_iterator'
// because the 'Pair' type does not distinguish
// between an iterator and a const_iterator.
//
typedef T type;
};
/*
template< class T >
struct range_difference< Foo::Pair<T> >
{
typedef typename std::iterator_traits<T>::difference_type type;
};
*/
template< class T >
struct range_size< Foo::Pair<T> >
{
int static_assertion[ sizeof( std::size_t ) >=
sizeof( typename range_difference< Foo::Pair<T> >::type ) ];
typedef std::size_t type;
};
} // namespace 'boost'
namespace Foo
{
//
// The required functions. These should be defined in
// the same namespace as 'Pair', in this case
// in namespace 'Foo'.
//
template< class T >
inline T boost_range_begin( Pair<T>& x )
{
return x.first;
}
template< class T >
inline T boost_range_begin( const Pair<T>& x )
{
return x.first;
}
template< class T >
inline T boost_range_end( Pair<T>& x )
{
return x.last;
}
template< class T >
inline T boost_range_end( const Pair<T>& x )
{
return x.last;
}
template< class T >
inline typename boost::range_size< Pair<T> >::type
boost_range_size( const Pair<T>& x )
{
return std::distance(x.first,x.last);
}
} // namespace 'Foo'
#include <vector>
int main()
{
typedef std::vector<int>::iterator iter;
std::vector<int> vec;
vec.push_back( 42 );
Foo::Pair<iter> pair = { vec.begin(), vec.end() };
const Foo::Pair<iter>& cpair = pair;
//
// Notice that we call 'begin' etc with qualification.
//
iter i = boost::begin( pair );
iter e = boost::end( pair );
i = boost::begin( cpair );
e = boost::end( cpair );
boost::range_size< Foo::Pair<iter> >::type s = boost::size( pair );
s = boost::size( cpair );
boost::range_const_reverse_iterator< Foo::Pair<iter> >::type
ri = boost::rbegin( cpair ),
re = boost::rend( cpair );
//
// Test metafunctions
//
boost::range_value< Foo::Pair<iter> >::type
v = *boost::begin(pair);
boost::range_difference< Foo::Pair<iter> >::type
d = boost::end(pair) - boost::begin(pair);
}
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