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
61