ceph/src/boost/boost/algorithm/cxx17/transform_inclusive_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  transform_reduce.hpp
   9 /// \brief Combine the (transformed) elements of a sequence (or two) into a single value.
  10 /// \author Marshall Clow
  11
  12 #ifndef BOOST_ALGORITHM_TRANSFORM_REDUCE_HPP
  13 #define BOOST_ALGORITHM_TRANSFORM_REDUCE_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,
  26          class BinaryOperation, class UnaryOperation, class T>
  27 OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
  28                                         OutputIterator result,
  29                                         BinaryOperation bOp, UnaryOperation uOp,
  30                                         T init)
  31 {
  32     for (; first != last; ++first, (void) ++result) {
  33         init = bOp(init, uOp(*first));
  34         *result = init;
  35         }
  36
  37     return result;
  38 }
  39
  40 template<class InputIterator, class OutputIterator,
  41          class BinaryOperation, class UnaryOperation>
  42 OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
  43                                         OutputIterator result,
  44                                         BinaryOperation bOp, UnaryOperation uOp)
  45 {
  46     if (first != last) {
  47         typename std::iterator_traits<InputIterator>::value_type init = uOp(*first);
  48         *result++ = init;
  49         if (++first != last)
  50             return boost::algorithm::transform_inclusive_scan
  51                                               (first, last, result, bOp, uOp, init);
  52         }
  53
  54     return result;
  55 }
  56
  57
  58 }} // namespace boost and algorithm
  59
  60 #endif // BOOST_ALGORITHM_TRANSFORM_REDUCE_HPP