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Diffstat (limited to 'src/third_party/boost-1.60.0/boost/next_prior.hpp')
-rw-r--r-- | src/third_party/boost-1.60.0/boost/next_prior.hpp | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/third_party/boost-1.60.0/boost/next_prior.hpp b/src/third_party/boost-1.60.0/boost/next_prior.hpp new file mode 100644 index 00000000000..7854ec436a4 --- /dev/null +++ b/src/third_party/boost-1.60.0/boost/next_prior.hpp @@ -0,0 +1,165 @@ +// Boost next_prior.hpp header file ---------------------------------------// + +// (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. + +// Revision History +// 13 Dec 2003 Added next(x, n) and prior(x, n) (Daniel Walker) + +#ifndef BOOST_NEXT_PRIOR_HPP_INCLUDED +#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 { + +// Helper functions for classes like bidirectional iterators not supporting +// operator+ and operator- +// +// Usage: +// const std::list<T>::iterator p = get_some_iterator(); +// const std::list<T>::iterator prev = boost::prior(p); +// const std::list<T>::iterator next = boost::next(prev, 2); + +// 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) +{ + return next_prior_detail::next_impl1< T, Distance >::call(x, n); +} + +template <class T> +inline T prior(T x) { return --x; } + +template <class T, class Distance> +inline T prior(T x, Distance n) +{ + return next_prior_detail::prior_impl1< T, Distance >::call(x, n); +} + +} // namespace boost + +#endif // BOOST_NEXT_PRIOR_HPP_INCLUDED |