116 lines
4.5 KiB
C++
116 lines
4.5 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <string>
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// UNSUPPORTED: c++03, c++11, c++14
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// template<class InputIterator,
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// class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
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// basic_string(InputIterator, InputIterator, Allocator = Allocator())
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// -> basic_string<typename iterator_traits<InputIterator>::value_type,
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// char_traits<typename iterator_traits<InputIterator>::value_type>,
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// Allocator>; // constexpr since C++20
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//
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// The deduction guide shall not participate in overload resolution if InputIterator
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// is a type that does not qualify as an input iterator, or if Allocator is a type
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// that does not qualify as an allocator.
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#include <cassert>
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#include <cstddef>
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#include <iterator>
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#include <string>
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#include <type_traits>
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#include "test_macros.h"
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#include "test_allocator.h"
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#include "min_allocator.h"
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class NotAnIterator {};
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using NotAnInputIterator = std::back_insert_iterator<std::basic_string<char16_t>>;
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template <typename T>
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struct NotAnAllocator { typedef T value_type; };
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template <class Iter, class Alloc, class = void>
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struct CanDeduce : std::false_type { };
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template <class Iter, class Alloc>
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struct CanDeduce<Iter, Alloc, decltype((void)
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std::basic_string{std::declval<Iter>(), std::declval<Iter>(), std::declval<Alloc>()}
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)> : std::true_type { };
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static_assert( CanDeduce<int*, std::allocator<int>>::value);
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static_assert(!CanDeduce<NotAnIterator, std::allocator<char>>::value);
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static_assert(!CanDeduce<NotAnInputIterator, std::allocator<char16_t>>::value);
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static_assert(!CanDeduce<wchar_t const*, NotAnAllocator<wchar_t>>::value);
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TEST_CONSTEXPR_CXX20 bool test() {
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{
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const char* s = "12345678901234";
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std::basic_string s1(s, s+10); // Can't use {} here
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using S = decltype(s1); // what type did we get?
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static_assert(std::is_same_v<S::value_type, char>, "");
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static_assert(std::is_same_v<S::traits_type, std::char_traits<char>>, "");
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static_assert(std::is_same_v<S::allocator_type, std::allocator<char>>, "");
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assert(s1.size() == 10);
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assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
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}
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{
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const char* s = "12345678901234";
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std::basic_string s1{s, s+10, std::allocator<char>{}};
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using S = decltype(s1); // what type did we get?
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static_assert(std::is_same_v<S::value_type, char>, "");
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static_assert(std::is_same_v<S::traits_type, std::char_traits<char>>, "");
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static_assert(std::is_same_v<S::allocator_type, std::allocator<char>>, "");
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assert(s1.size() == 10);
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assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
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}
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{
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const wchar_t* s = L"12345678901234";
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std::basic_string s1{s, s+10, test_allocator<wchar_t>{}};
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using S = decltype(s1); // what type did we get?
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static_assert(std::is_same_v<S::value_type, wchar_t>, "");
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static_assert(std::is_same_v<S::traits_type, std::char_traits<wchar_t>>, "");
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static_assert(std::is_same_v<S::allocator_type, test_allocator<wchar_t>>, "");
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assert(s1.size() == 10);
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assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
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}
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{
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const char16_t* s = u"12345678901234";
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std::basic_string s1{s, s+10, min_allocator<char16_t>{}};
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using S = decltype(s1); // what type did we get?
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static_assert(std::is_same_v<S::value_type, char16_t>, "");
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static_assert(std::is_same_v<S::traits_type, std::char_traits<char16_t>>, "");
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static_assert(std::is_same_v<S::allocator_type, min_allocator<char16_t>>, "");
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assert(s1.size() == 10);
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assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
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}
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{
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const char32_t* s = U"12345678901234";
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std::basic_string s1{s, s+10, explicit_allocator<char32_t>{}};
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using S = decltype(s1); // what type did we get?
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static_assert(std::is_same_v<S::value_type, char32_t>, "");
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static_assert(std::is_same_v<S::traits_type, std::char_traits<char32_t>>, "");
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static_assert(std::is_same_v<S::allocator_type, explicit_allocator<char32_t>>, "");
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assert(s1.size() == 10);
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assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
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}
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return true;
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}
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int main(int, char**)
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{
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test();
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#if TEST_STD_VER > 17
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static_assert(test());
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#endif
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return 0;
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}
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