// Boost next_prior.hpp header file ---------------------------------------//
-// (C) Copyright Boost.org 1999-2003. Permission to copy, use, modify, sell
-// and distribute this software is granted provided this copyright
-// notice appears in all copies. This software is provided "as is" without
-// express or implied warranty, and with no claim as to its suitability for
-// any purpose.
+// (C) Copyright Dave Abrahams and Daniel Walker 1999-2003. 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)
// See http://www.boost.org/libs/utility for documentation.
#define BOOST_NEXT_PRIOR_HPP_INCLUDED
#include <iterator>
+#if defined(_MSC_VER) && _MSC_VER <= 1310
+#include <boost/mpl/and.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#endif
+#include <boost/type_traits/is_unsigned.hpp>
+#include <boost/type_traits/integral_promotion.hpp>
+#include <boost/type_traits/make_signed.hpp>
+#include <boost/type_traits/has_plus.hpp>
+#include <boost/type_traits/has_plus_assign.hpp>
+#include <boost/type_traits/has_minus.hpp>
+#include <boost/type_traits/has_minus_assign.hpp>
namespace boost {
// Contributed by Dave Abrahams
+namespace next_prior_detail {
+
+template< typename T, typename Distance, bool HasPlus = has_plus< T, Distance >::value >
+struct next_impl2
+{
+ static T call(T x, Distance n)
+ {
+ std::advance(x, n);
+ return x;
+ }
+};
+
+template< typename T, typename Distance >
+struct next_impl2< T, Distance, true >
+{
+ static T call(T x, Distance n)
+ {
+ return x + n;
+ }
+};
+
+
+template< typename T, typename Distance, bool HasPlusAssign = has_plus_assign< T, Distance >::value >
+struct next_impl1 :
+ public next_impl2< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct next_impl1< T, Distance, true >
+{
+ static T call(T x, Distance n)
+ {
+ x += n;
+ return x;
+ }
+};
+
+
+template<
+ typename T,
+ typename Distance,
+ typename PromotedDistance = typename integral_promotion< Distance >::type,
+#if !defined(_MSC_VER) || _MSC_VER > 1310
+ bool IsUInt = is_unsigned< PromotedDistance >::value
+#else
+ // MSVC 7.1 has problems with applying is_unsigned to non-integral types
+ bool IsUInt = mpl::and_< is_integral< PromotedDistance >, is_unsigned< PromotedDistance > >::value
+#endif
+>
+struct prior_impl3
+{
+ static T call(T x, Distance n)
+ {
+ std::advance(x, -n);
+ return x;
+ }
+};
+
+template< typename T, typename Distance, typename PromotedDistance >
+struct prior_impl3< T, Distance, PromotedDistance, true >
+{
+ static T call(T x, Distance n)
+ {
+ typedef typename make_signed< PromotedDistance >::type signed_distance;
+ std::advance(x, -static_cast< signed_distance >(static_cast< PromotedDistance >(n)));
+ return x;
+ }
+};
+
+
+template< typename T, typename Distance, bool HasMinus = has_minus< T, Distance >::value >
+struct prior_impl2 :
+ public prior_impl3< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct prior_impl2< T, Distance, true >
+{
+ static T call(T x, Distance n)
+ {
+ return x - n;
+ }
+};
+
+
+template< typename T, typename Distance, bool HasMinusAssign = has_minus_assign< T, Distance >::value >
+struct prior_impl1 :
+ public prior_impl2< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct prior_impl1< T, Distance, true >
+{
+ static T call(T x, Distance n)
+ {
+ x -= n;
+ return x;
+ }
+};
+
+} // namespace next_prior_detail
+
template <class T>
inline T next(T x) { return ++x; }
template <class T, class Distance>
inline T next(T x, Distance n)
{
- std::advance(x, n);
- return x;
+ return next_prior_detail::next_impl1< T, Distance >::call(x, n);
}
template <class T>
template <class T, class Distance>
inline T prior(T x, Distance n)
{
- std::advance(x, -n);
- return x;
+ return next_prior_detail::prior_impl1< T, Distance >::call(x, n);
}
} // namespace boost