1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
/// \file
// Range v3 library
//
// Copyright Eric Niebler 2014-present
// Copyright Rostislav Khlebnikov 2017
//
// Use, modification and distribution is subject to the
// Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_V3_ALGORITHM_FOR_EACH_N_HPP
#define RANGES_V3_ALGORITHM_FOR_EACH_N_HPP
#include <functional>
#include <range/v3/range_fwd.hpp>
#include <range/v3/algorithm/result_types.hpp>
#include <range/v3/functional/identity.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/iterator/operations.hpp>
#include <range/v3/iterator/traits.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/dangling.hpp>
#include <range/v3/range/traits.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-algorithms
/// @{
RANGES_FUNC_BEGIN(for_each_n)
/// \brief function template \c for_each_n
template(typename I, typename F, typename P = identity)(
requires input_iterator<I> AND
indirectly_unary_invocable<F, projected<I, P>>)
constexpr I RANGES_FUNC(for_each_n)(I first, iter_difference_t<I> n, F fun, P proj = P{})
{
RANGES_EXPECT(0 <= n);
auto norig = n;
auto b = uncounted(first);
for(; 0 < n; ++b, --n)
invoke(fun, invoke(proj, *b));
return recounted(first, b, norig);
}
/// \overload
template(typename Rng, typename F, typename P = identity)(
requires input_range<Rng> AND
indirectly_unary_invocable<F, projected<iterator_t<Rng>, P>>)
constexpr borrowed_iterator_t<Rng> RANGES_FUNC(for_each_n)(
Rng && rng, range_difference_t<Rng> n, F fun, P proj = P{})
{
if(sized_range<Rng>)
RANGES_EXPECT(n <= distance(rng));
return (*this)(begin(rng), n, detail::move(fun), detail::move(proj));
}
RANGES_FUNC_END(for_each_n)
namespace cpp20
{
using ranges::for_each_n;
}
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
|
