williamr@2: // Boost next_prior.hpp header file ---------------------------------------// williamr@2: williamr@2: // (C) Copyright Dave Abrahams and Daniel Walker 1999-2003. Distributed under the Boost williamr@2: // Software License, Version 1.0. (See accompanying file williamr@2: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) williamr@2: williamr@2: // See http://www.boost.org/libs/utility for documentation. williamr@2: williamr@2: // Revision History williamr@2: // 13 Dec 2003 Added next(x, n) and prior(x, n) (Daniel Walker) williamr@2: williamr@2: #ifndef BOOST_NEXT_PRIOR_HPP_INCLUDED williamr@2: #define BOOST_NEXT_PRIOR_HPP_INCLUDED williamr@2: williamr@2: #include williamr@2: williamr@2: namespace boost { williamr@2: williamr@2: // Helper functions for classes like bidirectional iterators not supporting williamr@2: // operator+ and operator- williamr@2: // williamr@2: // Usage: williamr@2: // const std::list::iterator p = get_some_iterator(); williamr@2: // const std::list::iterator prev = boost::prior(p); williamr@2: // const std::list::iterator next = boost::next(prev, 2); williamr@2: williamr@2: // Contributed by Dave Abrahams williamr@2: williamr@2: template williamr@2: inline T next(T x) { return ++x; } williamr@2: williamr@2: template williamr@2: inline T next(T x, Distance n) williamr@2: { williamr@2: std::advance(x, n); williamr@2: return x; williamr@2: } williamr@2: williamr@2: template williamr@2: inline T prior(T x) { return --x; } williamr@2: williamr@2: template williamr@2: inline T prior(T x, Distance n) williamr@2: { williamr@2: std::advance(x, -n); williamr@2: return x; williamr@2: } williamr@2: williamr@2: } // namespace boost williamr@2: williamr@2: #endif // BOOST_NEXT_PRIOR_HPP_INCLUDED