ceph/src/boost/boost/algorithm/cxx17/exclusive_scan.hpp

   1 /*
   2    Copyright (c) Marshall Clow 2017.
   3
   4    Distributed under the Boost Software License, Version 1.0. (See accompanying
   5    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 */
   7
   8 /// \file  exclusive_scan.hpp
   9 /// \brief ???
  10 /// \author Marshall Clow
  11
  12 #ifndef BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP
  13 #define BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP
  14
  15 #include <functional>     // for std::plus
  16 #include <iterator>       // for std::iterator_traits
  17
  18 #include <boost/config.hpp>
  19 #include <boost/range/begin.hpp>
  20 #include <boost/range/end.hpp>
  21 #include <boost/range/value_type.hpp>
  22
  23 namespace boost { namespace algorithm {
  24
  25 template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
  26 OutputIterator exclusive_scan(InputIterator first, InputIterator last,
  27                               OutputIterator result, T init, BinaryOperation bOp)
  28 {
  29     if (first != last)
  30     {
  31         T saved = init;
  32         do
  33         {
  34             init = bOp(init, *first);
  35             *result = saved;
  36             saved = init;
  37             ++result;
  38         } while (++first != last);
  39     }
  40     return result;
  41 }
  42
  43 template<class InputIterator, class OutputIterator, class T>
  44 OutputIterator exclusive_scan(InputIterator first, InputIterator last,
  45                               OutputIterator result, T init)
  46 {
  47         typedef typename std::iterator_traits<InputIterator>::value_type VT;
  48     return boost::algorithm::exclusive_scan(first, last, result, init, std::plus<VT>());
  49 }
  50
  51 }} // namespace boost and algorithm
  52
  53 #endif // BOOST_ALGORITHM_EXCLUSIVE_SCAN_HPP