algorithm/cxx17/exclusive_scan.hpp

0001 /*
0002    Copyright (c) Marshall Clow 2017.
0003
0004    Distributed under the Boost Software License, Version 1.0. (See accompanying
0005    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 */
0007
0008 /// \file  exclusive_scan.hpp
0009 /// \brief ???
0010 /// \author Marshall Clow
0011
0012 #ifndef BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP
0013 #define BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP
0014
0015 #include <functional>     // for std::plus
0016 #include <iterator>       // for std::iterator_traits
0017
0018 #include <boost/config.hpp>
0019 #include <boost/range/begin.hpp>
0020 #include <boost/range/end.hpp>
0021 #include <boost/range/value_type.hpp>
0022
0023 namespace boost { namespace algorithm {
0024
0025 template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
0026 OutputIterator exclusive_scan(InputIterator first, InputIterator last,
0027                               OutputIterator result, T init, BinaryOperation bOp)
0028 {
0029     if (first != last)
0030     {
0031         T saved = init;
0032         do
0033         {
0034             init = bOp(init, *first);
0035             *result = saved;
0036             saved = init;
0037             ++result;
0038         } while (++first != last);
0039     }
0040     return result;
0041 }
0042
0043 template<class InputIterator, class OutputIterator, class T>
0044 OutputIterator exclusive_scan(InputIterator first, InputIterator last,
0045                               OutputIterator result, T init)
0046 {
0047     typedef typename std::iterator_traits<InputIterator>::value_type VT;
0048     return boost::algorithm::exclusive_scan(first, last, result, init, std::plus<VT>());
0049 }
0050
0051 }} // namespace boost and algorithm
0052
0053 #endif // BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP