1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03, c++11, c++14, c++17 10 // UNSUPPORTED: libcpp-no-concepts 11 // UNSUPPORTED: libcpp-has-no-incomplete-ranges 12 13 // take_view() requires default_initializable<V> = default; 14 15 #include <ranges> 16 #include <cassert> 17 18 int buff[8] = {1, 2, 3, 4, 5, 6, 7, 8}; 19 20 struct DefaultConstructible : std::ranges::view_base { 21 constexpr DefaultConstructible() : begin_(buff), end_(buff + 8) { } 22 constexpr int const* begin() const { return begin_; } 23 constexpr int const* end() const { return end_; } 24 private: 25 int const* begin_; 26 int const* end_; 27 }; 28 29 struct NonDefaultConstructible : std::ranges::view_base { 30 NonDefaultConstructible() = delete; 31 int* begin() const; 32 int* end() const; 33 }; 34 35 constexpr bool test() { 36 { 37 std::ranges::take_view<DefaultConstructible> tv; 38 assert(tv.begin() == buff); 39 assert(tv.size() == 0); 40 } 41 42 // Test SFINAE-friendliness 43 { 44 static_assert( std::is_default_constructible_v<std::ranges::take_view<DefaultConstructible>>); 45 static_assert(!std::is_default_constructible_v<std::ranges::take_view<NonDefaultConstructible>>); 46 } 47 48 return true; 49 } 50 51 int main(int, char**) { 52 test(); 53 static_assert(test()); 54 55 return 0; 56 } 57