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max.hpp
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1 // Range v3 library
3 //
4 // Copyright Eric Niebler 2014-present
5 // Copyright Casey Carter 2015
6 //
7 // Use, modification and distribution is subject to the
8 // Boost Software License, Version 1.0. (See accompanying
9 // file LICENSE_1_0.txt or copy at
10 // http://www.boost.org/LICENSE_1_0.txt)
11 //
12 // Project home: https://github.com/ericniebler/range-v3
13 //
14 #ifndef RANGES_V3_ALGORITHM_MAX_HPP
15 #define RANGES_V3_ALGORITHM_MAX_HPP
16 
17 #include <initializer_list>
18 
19 #include <range/v3/range_fwd.hpp>
20 
29 #include <range/v3/utility/static_const.hpp>
30 
31 #include <range/v3/detail/prologue.hpp>
32 
33 namespace ranges
34 {
37  RANGES_FUNC_BEGIN(max)
38 
39 
40  template(typename T, typename C = less, typename P = identity)(
41  requires indirect_strict_weak_order<C, projected<T const *, P>>)
42  constexpr T const & RANGES_FUNC(max)(
43  T const & a, T const & b, C pred = C{}, P proj = P{}) //
44  {
45  return invoke(pred, invoke(proj, b), invoke(proj, a)) ? a : b;
46  }
47 
49  template(typename Rng, typename C = less, typename P = identity)(
50  requires input_range<Rng> AND
51  indirect_strict_weak_order<C, projected<iterator_t<Rng>, P>> AND
52  indirectly_copyable_storable<iterator_t<Rng>, range_value_t<Rng> *>)
53  constexpr range_value_t<Rng> //
54  RANGES_FUNC(max)(Rng && rng, C pred = C{}, P proj = P{}) //
55  {
56  auto first = ranges::begin(rng);
57  auto last = ranges::end(rng);
58  RANGES_EXPECT(first != last);
59  range_value_t<Rng> result = *first;
60  while(++first != last)
61  {
62  auto && tmp = *first;
63  if(invoke(pred, invoke(proj, result), invoke(proj, tmp)))
64  result = (decltype(tmp) &&)tmp;
65  }
66  return result;
67  }
68 
70  template(typename T, typename C = less, typename P = identity)(
71  requires copyable<T> AND
72  indirect_strict_weak_order<C, projected<T const *, P>>)
73  constexpr T RANGES_FUNC(max)(
74  std::initializer_list<T> const && rng, C pred = C{}, P proj = P{}) //
75  {
76  return (*this)(rng, std::move(pred), std::move(proj));
77  }
78 
79  RANGES_FUNC_END(max)
80 
81  namespace cpp20
82  {
83  using ranges::max;
84  }
86 } // namespace ranges
87 
88 #include <range/v3/detail/epilogue.hpp>
89 
90 #endif
template(typename T, typename C=less, typename P=identity)(requires indirect_strict_weak_order< C
function template max
CPP_concept indirect_strict_weak_order
\concept indirect_strict_weak_order
Definition: concepts.hpp:689
CPP_concept indirectly_copyable_storable
\concept indirectly_copyable_storable
Definition: concepts.hpp:798
typename Fn::template invoke< Args... > invoke
Evaluate the invocable Fn with the arguments Args.
Definition: meta.hpp:541
front< Pair > first
Retrieve the first element of the pair Pair.
Definition: meta.hpp:2251
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