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merge.hpp
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1 // Range v3 library
3 //
4 // Copyright Eric Niebler 2014-present
5 //
6 // Use, modification and distribution is subject to the
7 // Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10 //
11 // Project home: https://github.com/ericniebler/range-v3
12 //
13 // Copyright (c) 2009 Alexander Stepanov and Paul McJones
14 //
15 // Permission to use, copy, modify, distribute and sell this software
16 // and its documentation for any purpose is hereby granted without
17 // fee, provided that the above copyright notice appear in all copies
18 // and that both that copyright notice and this permission notice
19 // appear in supporting documentation. The authors make no
20 // representations about the suitability of this software for any
21 // purpose. It is provided "as is" without express or implied
22 // warranty.
23 //
24 // Algorithms from
25 // Elements of Programming
26 // by Alexander Stepanov and Paul McJones
27 // Addison-Wesley Professional, 2009
28 
29 #ifndef RANGES_V3_ALGORITHM_MERGE_HPP
30 #define RANGES_V3_ALGORITHM_MERGE_HPP
31 
32 #include <tuple>
33 
34 #include <range/v3/range_fwd.hpp>
35 
37 #include <range/v3/algorithm/result_types.hpp>
46 #include <range/v3/utility/static_const.hpp>
47 
48 #include <range/v3/detail/prologue.hpp>
49 
50 namespace ranges
51 {
54  template<typename I0, typename I1, typename O>
55  using merge_result = detail::in1_in2_out_result<I0, I1, O>;
56 
57  RANGES_FUNC_BEGIN(merge)
58 
59 
60  template(typename I0,
61  typename S0,
62  typename I1,
63  typename S1,
64  typename O,
65  typename C = less,
66  typename P0 = identity,
67  typename P1 = identity)(
68  requires sentinel_for<S0, I0> AND sentinel_for<S1, I1> AND
69  mergeable<I0, I1, O, C, P0, P1>)
70  constexpr merge_result<I0, I1, O> RANGES_FUNC(merge)(I0 begin0,
71  S0 end0,
72  I1 begin1,
73  S1 end1,
74  O out,
75  C pred = C{},
76  P0 proj0 = P0{},
77  P1 proj1 = P1{}) //
78  {
79  for(; begin0 != end0 && begin1 != end1; ++out)
80  {
81  if(invoke(pred, invoke(proj1, *begin1), invoke(proj0, *begin0)))
82  {
83  *out = *begin1;
84  ++begin1;
85  }
86  else
87  {
88  *out = *begin0;
89  ++begin0;
90  }
91  }
92  auto t0 = ranges::copy(begin0, end0, out);
93  auto t1 = ranges::copy(begin1, end1, t0.out);
94  return {t0.in, t1.in, t1.out};
95  }
96 
98  template(typename Rng0,
99  typename Rng1,
100  typename O,
101  typename C = less,
102  typename P0 = identity,
103  typename P1 = identity)(
104  requires range<Rng0> AND range<Rng1> AND
105  mergeable<iterator_t<Rng0>, iterator_t<Rng1>, O, C, P0, P1>)
106  constexpr merge_result<borrowed_iterator_t<Rng0>, borrowed_iterator_t<Rng1>, O>
107  RANGES_FUNC(merge)(Rng0 && rng0,
108  Rng1 && rng1,
109  O out,
110  C pred = C{},
111  P0 proj0 = P0{},
112  P1 proj1 = P1{})
113  {
114  return (*this)(begin(rng0),
115  end(rng0),
116  begin(rng1),
117  end(rng1),
118  std::move(out),
119  std::move(pred),
120  std::move(proj0),
121  std::move(proj1));
122  }
123 
124  RANGES_FUNC_END(merge)
125 
126  namespace cpp20
127  {
128  using ranges::merge;
129  using ranges::merge_result;
130  } // namespace cpp20
132 } // namespace ranges
133 
134 #include <range/v3/detail/epilogue.hpp>
135 
136 #endif
template(typename Rng0, typename Rng1, typename O, typename C=less, typename P0=identity, typename P1=identity)(requires range< Rng0 > AND range< Rng1 > AND mergeable< iterator_t< Rng0 >
This is an overloaded member function, provided for convenience. It differs from the above function o...
CPP_concept sentinel_for
\concept sentinel_for
Definition: concepts.hpp:306
decltype(begin(declval(Rng &))) iterator_t
Definition: access.hpp:698
typename Fn::template invoke< Args... > invoke
Evaluate the invocable Fn with the arguments Args.
Definition: meta.hpp:541
bool_<(T::type::value< U::type::value)> less
A Boolean integral constant wrapper around true if T::type::value is less than U::type::value; false,...
Definition: meta.hpp:255
Definition: identity.hpp:25
Definition: comparisons.hpp:50