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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <memory>
// unique_ptr
// T& unique_ptr::operator[](size_t) const
#include <memory>
#include <cassert>
#include <type_traits>
#include <array>
#include "test_macros.h"
#include "type_algorithms.h"
static int next = 0;
struct EnumeratedDefaultCtor {
EnumeratedDefaultCtor() : value(0) { value = ++next; }
int value;
};
template <std::size_t Size>
struct WithTrivialDtor {
std::array<char, Size> padding = {'x'};
TEST_CONSTEXPR_CXX23 friend bool operator==(WithTrivialDtor const& x, WithTrivialDtor const& y) {
return x.padding == y.padding;
}
};
template <std::size_t Size>
struct WithNonTrivialDtor {
std::array<char, Size> padding = {'x'};
TEST_CONSTEXPR_CXX23 friend bool operator==(WithNonTrivialDtor const& x, WithNonTrivialDtor const& y) {
return x.padding == y.padding;
}
TEST_CONSTEXPR_CXX23 ~WithNonTrivialDtor() {}
};
template <class T>
struct CustomDeleter : std::default_delete<T> {};
struct NoopDeleter {
template <class T>
TEST_CONSTEXPR_CXX23 void operator()(T*) const {}
};
TEST_CONSTEXPR_CXX23 bool test() {
// Basic test
{
std::unique_ptr<int[]> p(new int[3]);
{
int& result = p[0];
result = 0;
}
{
int& result = p[1];
result = 1;
}
{
int& result = p[2];
result = 2;
}
assert(p[0] == 0);
assert(p[1] == 1);
assert(p[2] == 2);
}
// Ensure that the order of access is correct after initializing a unique_ptr but
// before actually modifying any of its elements. The implementation would have to
// really try for this not to be the case, but we still check it.
//
// This requires assigning known values to the elements when they are first constructed,
// which requires global state.
{
if (!TEST_IS_CONSTANT_EVALUATED) {
std::unique_ptr<EnumeratedDefaultCtor[]> p(new EnumeratedDefaultCtor[3]);
assert(p[0].value == 1);
assert(p[1].value == 2);
assert(p[2].value == 3);
}
}
// Make sure operator[] is const-qualified
{
std::unique_ptr<int[]> const p(new int[3]);
p[0] = 42;
assert(p[0] == 42);
}
// Make sure we properly handle types with trivial and non-trivial destructors of different
// sizes. This is relevant because some implementations may want to use properties of the
// ABI like array cookies and these properties often depend on e.g. the triviality of T's
// destructor, T's size and so on.
#if TEST_STD_VER >= 20 // this test is too painful to write before C++20
{
using TrickyCookieTypes = types::type_list<
WithTrivialDtor<1>,
WithTrivialDtor<2>,
WithTrivialDtor<3>,
WithTrivialDtor<4>,
WithTrivialDtor<8>,
WithTrivialDtor<16>,
WithTrivialDtor<256>,
WithNonTrivialDtor<1>,
WithNonTrivialDtor<2>,
WithNonTrivialDtor<3>,
WithNonTrivialDtor<4>,
WithNonTrivialDtor<8>,
WithNonTrivialDtor<16>,
WithNonTrivialDtor<256>>;
types::for_each(TrickyCookieTypes(), []<class T> {
// Array allocated with `new T[n]`, default deleter
{
std::unique_ptr<T[], std::default_delete<T[]>> p(new T[3]);
assert(p[0] == T());
assert(p[1] == T());
assert(p[2] == T());
}
// Array allocated with `new T[n]`, custom deleter
{
std::unique_ptr<T[], CustomDeleter<T[]>> p(new T[3]);
assert(p[0] == T());
assert(p[1] == T());
assert(p[2] == T());
}
// Array not allocated with `new T[n]`, custom deleter
//
// This test aims to ensure that the implementation doesn't try to use an array cookie
// when there is none.
{
T array[50] = {};
std::unique_ptr<T[], NoopDeleter> p(&array[0]);
assert(p[0] == T());
assert(p[1] == T());
assert(p[2] == T());
}
});
}
#endif // C++20
return true;
}
int main(int, char**) {
test();
#if TEST_STD_VER >= 23
static_assert(test());
#endif
return 0;
}
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