1*eea3d90aSKonstantin Varlamov //===----------------------------------------------------------------------===// 2*eea3d90aSKonstantin Varlamov // 3*eea3d90aSKonstantin Varlamov // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*eea3d90aSKonstantin Varlamov // See https://llvm.org/LICENSE.txt for license information. 5*eea3d90aSKonstantin Varlamov // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*eea3d90aSKonstantin Varlamov // 7*eea3d90aSKonstantin Varlamov //===----------------------------------------------------------------------===// 8*eea3d90aSKonstantin Varlamov 9*eea3d90aSKonstantin Varlamov // UNSUPPORTED: c++03, c++11, c++14, c++17 10*eea3d90aSKonstantin Varlamov 11*eea3d90aSKonstantin Varlamov // template<class I1, class I2, class Out, 12*eea3d90aSKonstantin Varlamov // class R = ranges::less, class P1 = identity, class P2 = identity> 13*eea3d90aSKonstantin Varlamov // concept mergeable = see below; // since C++20 14*eea3d90aSKonstantin Varlamov 15*eea3d90aSKonstantin Varlamov #include <iterator> 16*eea3d90aSKonstantin Varlamov 17*eea3d90aSKonstantin Varlamov #include <functional> 18*eea3d90aSKonstantin Varlamov 19*eea3d90aSKonstantin Varlamov #include "test_iterators.h" 20*eea3d90aSKonstantin Varlamov #include "test_macros.h" 21*eea3d90aSKonstantin Varlamov 22*eea3d90aSKonstantin Varlamov using CompDefault = std::ranges::less; 23*eea3d90aSKonstantin Varlamov using CompInt = bool(*)(int, int); 24*eea3d90aSKonstantin Varlamov using ProjDefault = std::identity; 25*eea3d90aSKonstantin Varlamov 26*eea3d90aSKonstantin Varlamov using Input = cpp20_input_iterator<int*>; 27*eea3d90aSKonstantin Varlamov static_assert( std::input_iterator<Input>); 28*eea3d90aSKonstantin Varlamov using InputLong = cpp20_input_iterator<long*>; 29*eea3d90aSKonstantin Varlamov static_assert( std::input_iterator<InputLong>); 30*eea3d90aSKonstantin Varlamov 31*eea3d90aSKonstantin Varlamov using Output = cpp17_output_iterator<int*>; 32*eea3d90aSKonstantin Varlamov static_assert( std::weakly_incrementable<Output>); 33*eea3d90aSKonstantin Varlamov 34*eea3d90aSKonstantin Varlamov static_assert( std::indirectly_copyable<Input, Output>); 35*eea3d90aSKonstantin Varlamov static_assert( std::indirectly_copyable<InputLong, Output>); 36*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompDefault, Input, Input>); 37*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompInt, Input, Input>); 38*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompDefault, Input, InputLong>); 39*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompInt, Input, InputLong>); 40*eea3d90aSKonstantin Varlamov 41*eea3d90aSKonstantin Varlamov // All requirements satisfied. 42*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output>); 43*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, CompInt>); 44*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, CompInt, ProjDefault>); 45*eea3d90aSKonstantin Varlamov 46*eea3d90aSKonstantin Varlamov // Non-default projections. 47*eea3d90aSKonstantin Varlamov struct Foo {}; 48*eea3d90aSKonstantin Varlamov using ProjFooToInt = int(*)(Foo); 49*eea3d90aSKonstantin Varlamov using ProjFooToLong = long(*)(Foo); 50*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompDefault, 51*eea3d90aSKonstantin Varlamov std::projected<Foo*, ProjFooToInt>, std::projected<Foo*, ProjFooToLong>>); 52*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Foo*, Foo*, Foo*, CompDefault, ProjFooToInt, ProjFooToLong>); 53*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompInt, 54*eea3d90aSKonstantin Varlamov std::projected<Foo*, ProjFooToInt>, std::projected<Foo*, ProjFooToLong>>); 55*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Foo*, Foo*, Foo*, CompInt, ProjFooToInt, ProjFooToLong>); 56*eea3d90aSKonstantin Varlamov 57*eea3d90aSKonstantin Varlamov // I1 or I2 is not an input iterator. 58*eea3d90aSKonstantin Varlamov static_assert(!std::input_iterator<Output>); 59*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Output, Input, Output>); 60*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Output, Output>); 61*eea3d90aSKonstantin Varlamov 62*eea3d90aSKonstantin Varlamov // O is not weakly incrementable. 63*eea3d90aSKonstantin Varlamov struct NotWeaklyIncrementable { 64*eea3d90aSKonstantin Varlamov int& operator*() const; 65*eea3d90aSKonstantin Varlamov }; 66*eea3d90aSKonstantin Varlamov 67*eea3d90aSKonstantin Varlamov static_assert(!std::weakly_incrementable<NotWeaklyIncrementable>); 68*eea3d90aSKonstantin Varlamov static_assert( std::indirectly_copyable<Input, NotWeaklyIncrementable>); 69*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompDefault, Input, Input>); 70*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, NotWeaklyIncrementable>); 71*eea3d90aSKonstantin Varlamov 72*eea3d90aSKonstantin Varlamov // I1 or I2 is not indirectly copyable into O. 73*eea3d90aSKonstantin Varlamov struct AssignableOnlyFromInt { 74*eea3d90aSKonstantin Varlamov AssignableOnlyFromInt& operator=(int); 75*eea3d90aSKonstantin Varlamov template <class T> 76*eea3d90aSKonstantin Varlamov AssignableOnlyFromInt& operator=(T) = delete; 77*eea3d90aSKonstantin Varlamov }; 78*eea3d90aSKonstantin Varlamov using OutputOnlyInt = cpp17_output_iterator<AssignableOnlyFromInt*>; 79*eea3d90aSKonstantin Varlamov static_assert( std::weakly_incrementable<OutputOnlyInt>); 80*eea3d90aSKonstantin Varlamov 81*eea3d90aSKonstantin Varlamov static_assert( std::indirectly_copyable<Input, OutputOnlyInt>); 82*eea3d90aSKonstantin Varlamov static_assert(!std::indirectly_copyable<InputLong, OutputOnlyInt>); 83*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<CompDefault, Input, InputLong>); 84*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, OutputOnlyInt>); 85*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, InputLong, OutputOnlyInt>); 86*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<InputLong, Input, OutputOnlyInt>); 87*eea3d90aSKonstantin Varlamov 88*eea3d90aSKonstantin Varlamov // No indirect strict weak order between I1 and I2 (bad comparison functor). 89*eea3d90aSKonstantin Varlamov using GoodComp = bool(*)(int, int); 90*eea3d90aSKonstantin Varlamov static_assert( std::indirect_strict_weak_order<GoodComp, Input, Input>); 91*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, GoodComp>); 92*eea3d90aSKonstantin Varlamov using BadComp = bool(*)(int*, int*); 93*eea3d90aSKonstantin Varlamov static_assert(!std::indirect_strict_weak_order<BadComp, Input, Input>); 94*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, Output, BadComp>); 95*eea3d90aSKonstantin Varlamov 96*eea3d90aSKonstantin Varlamov // No indirect strict weak order between I1 and I2 (bad projection). 97*eea3d90aSKonstantin Varlamov using ToInt = int(*)(int); 98*eea3d90aSKonstantin Varlamov using ToPtr = int*(*)(int); 99*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, GoodComp, std::identity, std::identity>); 100*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, GoodComp, ToInt, ToInt>); 101*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, Output, GoodComp, ToPtr, ToInt>); 102*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, Output, GoodComp, ToInt, ToPtr>); 103*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, Output, bool(*)(int*, int), ToPtr, ToInt>); 104*eea3d90aSKonstantin Varlamov static_assert(!std::mergeable<Input, Input, Output, bool(*)(int, int*), ToInt, ToPtr>); 105*eea3d90aSKonstantin Varlamov 106*eea3d90aSKonstantin Varlamov // A projection that only supports non-const references and has a non-const `operator()` still has to work. 107*eea3d90aSKonstantin Varlamov struct ProjectionOnlyMutable { 108*eea3d90aSKonstantin Varlamov int operator()(int&); 109*eea3d90aSKonstantin Varlamov int operator()(int&&) const = delete; 110*eea3d90aSKonstantin Varlamov }; 111*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, Output, CompDefault, ProjectionOnlyMutable, ProjectionOnlyMutable>); 112*eea3d90aSKonstantin Varlamov 113*eea3d90aSKonstantin Varlamov // The output is weakly incrementable but not an output iterator. 114*eea3d90aSKonstantin Varlamov struct WeaklyIncrementable { 115*eea3d90aSKonstantin Varlamov using value_type = int; 116*eea3d90aSKonstantin Varlamov using difference_type = int; 117*eea3d90aSKonstantin Varlamov 118*eea3d90aSKonstantin Varlamov int& operator*() const; 119*eea3d90aSKonstantin Varlamov WeaklyIncrementable& operator++(); 120*eea3d90aSKonstantin Varlamov // `output_iterator` requires `i++` to return an iterator, 121*eea3d90aSKonstantin Varlamov // while `weakly_incrementable` requires only that `i++` be well-formed. 122*eea3d90aSKonstantin Varlamov void operator++(int); 123*eea3d90aSKonstantin Varlamov }; 124*eea3d90aSKonstantin Varlamov static_assert( std::weakly_incrementable<WeaklyIncrementable>); 125*eea3d90aSKonstantin Varlamov static_assert( std::indirectly_copyable<int*, WeaklyIncrementable>); 126*eea3d90aSKonstantin Varlamov static_assert(!std::output_iterator<WeaklyIncrementable, int>); 127*eea3d90aSKonstantin Varlamov static_assert( std::mergeable<Input, Input, WeaklyIncrementable>); 128