| // Copyright (C) 2019-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING3. If not see |
| // <http://www.gnu.org/licenses/>. |
| |
| // { dg-options "-std=gnu++2a" } |
| // { dg-do run { target c++2a } } |
| |
| #include <ranges> |
| #include <utility> // as_const |
| #include <testsuite_hooks.h> |
| #include <testsuite_iterators.h> |
| |
| static_assert(__gnu_test::is_customization_point_object(std::ranges::cbegin)); |
| |
| using std::same_as; |
| |
| void |
| test01() |
| { |
| int a[2] = {}; |
| |
| static_assert(same_as<decltype(std::ranges::cbegin(a)), const int*>); |
| static_assert(noexcept(std::ranges::cbegin(a))); |
| VERIFY( std::ranges::cbegin(a) == (a + 0) ); |
| |
| constexpr long b[2] = {}; |
| static_assert( std::ranges::cbegin(b) == (b + 0) ); |
| } |
| |
| struct R |
| { |
| int a[4] = { 0, 1, 2, 3 }; |
| |
| friend int* begin(R& r) { return r.a + 0; } |
| friend int* begin(R&&); // this function is not defined |
| friend const int* begin(const R& r) noexcept { return r.a + 2; } |
| friend const int* begin(const R&&); // this function is not defined |
| }; |
| |
| struct RV // view on an R |
| { |
| R& r; |
| |
| friend int* begin(RV&); // this function is not defined |
| friend const int* begin(const RV& rv) noexcept { return begin(std::as_const(rv.r)); } |
| }; |
| |
| // Allow ranges::begin to work with RV&& |
| template<> constexpr bool std::ranges::enable_borrowed_range<RV> = true; |
| |
| void |
| test03() |
| { |
| R r; |
| const R& c = r; |
| VERIFY(std::ranges::cbegin(r) == std::ranges::begin(c)); |
| VERIFY(std::ranges::cbegin(c) == std::ranges::begin(c)); |
| |
| RV v{r}; |
| VERIFY(std::ranges::cbegin(std::move(v)) == std::ranges::begin(c)); |
| const RV cv{r}; |
| VERIFY(std::ranges::cbegin(std::move(cv)) == std::ranges::begin(c)); |
| } |
| |
| struct RR |
| { |
| short s = 0; |
| long l = 0; |
| int a[4] = { 0, 1, 2, 3 }; |
| |
| short* begin() noexcept { return &s; } |
| const long* begin() const { return &l; } |
| |
| friend int* begin(RR& r) { return r.a + 0; } |
| friend int* begin(RR&& r) { return r.a + 1; } |
| friend const int* begin(const RR& r) { return r.a + 2; } |
| friend const int* begin(const RR&& r) noexcept { return r.a + 3; } |
| }; |
| |
| // N.B. this is a lie, cbegin on an RR rvalue will return a dangling pointer. |
| template<> constexpr bool std::ranges::enable_borrowed_range<RR> = true; |
| |
| void |
| test04() |
| { |
| RR r; |
| const RR& c = r; |
| VERIFY(std::ranges::cbegin(r) == std::ranges::begin(c)); |
| VERIFY(std::ranges::cbegin(std::move(r)) == std::ranges::begin(c)); |
| VERIFY(std::ranges::cbegin(c) == std::ranges::begin(c)); |
| VERIFY(std::ranges::cbegin(std::move(c)) == std::ranges::begin(c)); |
| } |
| |
| int |
| main() |
| { |
| test01(); |
| test03(); |
| test04(); |
| } |