| // 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 <testsuite_hooks.h> |
| #include <testsuite_iterators.h> |
| |
| static_assert(__gnu_test::is_customization_point_object(std::ranges::begin)); |
| |
| using std::same_as; |
| |
| void |
| test01() |
| { |
| int a[2] = {}; |
| |
| static_assert(same_as<decltype(std::ranges::begin(a)), decltype(a + 0)>); |
| static_assert(noexcept(std::ranges::begin(a))); |
| VERIFY( std::ranges::begin(a) == (a + 0) ); |
| |
| constexpr long b[2] = { }; |
| static_assert( std::ranges::begin(b) == (b + 0) ); |
| |
| struct X { }; |
| using A = X[]; // unbounded array |
| extern A& f(); |
| static_assert( same_as<decltype(std::ranges::begin(f())), X*> ); |
| } |
| |
| void |
| test02() |
| { |
| using __gnu_test::test_range; |
| using __gnu_test::random_access_iterator_wrapper; |
| using __gnu_test::input_iterator_wrapper; |
| using __gnu_test::output_iterator_wrapper; |
| |
| int a[] = { 0, 1 }; |
| |
| test_range<int, random_access_iterator_wrapper> r(a); |
| static_assert(same_as<decltype(std::ranges::begin(r)), decltype(r.begin())>); |
| VERIFY( std::ranges::begin(r) == r.begin() ); |
| |
| test_range<int, input_iterator_wrapper> i(a); |
| static_assert(same_as<decltype(std::ranges::begin(i)), decltype(i.begin())>); |
| VERIFY( std::ranges::begin(i) == i.begin() ); |
| |
| test_range<int, output_iterator_wrapper> o(a); |
| static_assert(same_as<decltype(std::ranges::begin(o)), decltype(o.begin())>); |
| *std::ranges::begin(o) = 99; |
| VERIFY( a[0] == 99 ); |
| } |
| |
| struct R |
| { |
| int a[4] = { 0, 1, 2, 3 }; |
| |
| friend int* begin(R& r) { return r.a + 0; } |
| friend int* begin(R&& r); // this overload is not defined |
| friend const int* begin(const R& r) noexcept { return r.a + 2; } |
| friend const int* begin(const R&& r) noexcept; // not defined |
| }; |
| |
| struct RV // view on an R |
| { |
| R& r; |
| |
| friend int* begin(RV& rv) { return begin(rv.r); } |
| friend const int* begin(const RV& rv) noexcept { return begin(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; |
| |
| static_assert(same_as<decltype(std::ranges::begin(r)), decltype(begin(r))>); |
| static_assert(!noexcept(std::ranges::begin(r))); |
| VERIFY( std::ranges::begin(r) == begin(r) ); |
| |
| static_assert(same_as<decltype(std::ranges::begin(c)), decltype(begin(c))>); |
| static_assert(noexcept(std::ranges::begin(c))); |
| VERIFY( std::ranges::begin(c) == begin(c) ); |
| |
| RV v{r}; |
| // enable_borrowed_range<RV> allows ranges::begin to work for rvalues, |
| // but it will call v.begin() or begin(v) on an lvalue: |
| static_assert(same_as<decltype(std::ranges::begin(std::move(v))), |
| decltype(begin(v))>); |
| static_assert(!noexcept(std::ranges::begin(std::move(v)))); |
| VERIFY( std::ranges::begin(std::move(v)) == begin(v) ); |
| |
| const RV cv{r}; |
| static_assert(same_as<decltype(std::ranges::begin(std::move(cv))), |
| decltype(begin(cv))>); |
| static_assert(noexcept(std::ranges::begin(std::move(cv)))); |
| VERIFY( std::ranges::begin(std::move(cv)) == begin(cv) ); |
| } |
| |
| 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) noexcept { return r.a + 0; } |
| friend int* begin(RR&& r); // not defined |
| friend const int* begin(const RR& r) { return r.a + 2; } |
| friend const int* begin(const RR&& r) noexcept; // not defined |
| }; |
| |
| // N.B. this is a lie, begin 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::begin(r) == &r.s ); |
| static_assert(noexcept(std::ranges::begin(r))); |
| |
| // calls r.begin() on an lvalue, not rvalue |
| VERIFY( std::ranges::begin(std::move(r)) == std::ranges::begin(r) ); |
| static_assert(noexcept(std::ranges::begin(std::move(r)))); |
| |
| VERIFY( std::ranges::begin(c) == &r.l ); |
| static_assert(!noexcept(std::ranges::begin(c))); |
| |
| // calls r.begin() on a const lvalue, not rvalue |
| VERIFY( std::ranges::begin(std::move(c)) == std::ranges::begin(c) ); |
| static_assert(!noexcept(std::ranges::begin(std::move(c)))); |
| } |
| |
| int |
| main() |
| { |
| test01(); |
| test02(); |
| test03(); |
| test04(); |
| } |