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// -*- C++ -*-
//===------------------------------ span ---------------------------------===//
//
// 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
//
//===---------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <span>
// template<class OtherElementType, ptrdiff_t OtherExtent>
// constexpr span(const span<OtherElementType, OtherExtent>& s) noexcept;
//
// Remarks: This constructor shall not participate in overload resolution unless:
// Extent == dynamic_extent || Extent == OtherExtent is true, and
// OtherElementType(*)[] is convertible to ElementType(*)[].
#include <span>
#include <cassert>
#include <string>
#include "test_macros.h"
void checkCV()
{
std::span< int> sp;
// std::span<const int> csp;
std::span< volatile int> vsp;
// std::span<const volatile int> cvsp;
std::span< int, 0> sp0;
// std::span<const int, 0> csp0;
std::span< volatile int, 0> vsp0;
// std::span<const volatile int, 0> cvsp0;
// dynamic -> dynamic
{
std::span<const int> s1{ sp}; // a span<const int> pointing at int.
std::span< volatile int> s2{ sp}; // a span< volatile int> pointing at int.
std::span<const volatile int> s3{ sp}; // a span<const volatile int> pointing at int.
std::span<const volatile int> s4{ vsp}; // a span<const volatile int> pointing at volatile int.
assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
}
// static -> static
{
std::span<const int, 0> s1{ sp0}; // a span<const int> pointing at int.
std::span< volatile int, 0> s2{ sp0}; // a span< volatile int> pointing at int.
std::span<const volatile int, 0> s3{ sp0}; // a span<const volatile int> pointing at int.
std::span<const volatile int, 0> s4{ vsp0}; // a span<const volatile int> pointing at volatile int.
assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
}
// static -> dynamic
{
std::span<const int> s1{ sp0}; // a span<const int> pointing at int.
std::span< volatile int> s2{ sp0}; // a span< volatile int> pointing at int.
std::span<const volatile int> s3{ sp0}; // a span<const volatile int> pointing at int.
std::span<const volatile int> s4{ vsp0}; // a span<const volatile int> pointing at volatile int.
assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
}
// dynamic -> static
{
std::span<const int, 0> s1{ sp}; // a span<const int> pointing at int.
std::span< volatile int, 0> s2{ sp}; // a span< volatile int> pointing at int.
std::span<const volatile int, 0> s3{ sp}; // a span<const volatile int> pointing at int.
std::span<const volatile int, 0> s4{ vsp}; // a span<const volatile int> pointing at volatile int.
assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
}
}
template <typename T>
constexpr bool testConstexprSpan()
{
std::span<T> s0{};
std::span<T, 0> s1(s0); // dynamic -> static
std::span<T> s2(s1); // static -> dynamic
ASSERT_NOEXCEPT(std::span<T> {s0});
ASSERT_NOEXCEPT(std::span<T, 0>{s1});
ASSERT_NOEXCEPT(std::span<T> {s1});
ASSERT_NOEXCEPT(std::span<T, 0>{s0});
return
s1.data() == nullptr && s1.size() == 0
&& s2.data() == nullptr && s2.size() == 0;
}
template <typename T>
void testRuntimeSpan()
{
std::span<T> s0{};
std::span<T, 0> s1(s0); // dynamic -> static
std::span<T> s2(s1); // static -> dynamic
ASSERT_NOEXCEPT(std::span<T> {s0});
ASSERT_NOEXCEPT(std::span<T, 0>{s1});
ASSERT_NOEXCEPT(std::span<T> {s1});
ASSERT_NOEXCEPT(std::span<T, 0>{s0});
assert(s1.data() == nullptr && s1.size() == 0);
assert(s2.data() == nullptr && s2.size() == 0);
}
template <typename Dest, typename Src>
bool testConversionSpan()
{
static_assert(std::is_convertible_v<Src(*)[], Dest(*)[]>, "Bad input types to 'testConversionSpan");
std::span<Src> s0d{};
std::span<Src> s0s{};
std::span<Dest, 0> s1(s0d); // dynamic -> static
std::span<Dest> s2(s0s); // static -> dynamic
s1.data() == nullptr && s1.size() == 0
&& s2.data() == nullptr && s2.size() == 0;
}
struct A{};
int main ()
{
static_assert(testConstexprSpan<int>(), "");
static_assert(testConstexprSpan<long>(), "");
static_assert(testConstexprSpan<double>(), "");
static_assert(testConstexprSpan<A>(), "");
testRuntimeSpan<int>();
testRuntimeSpan<long>();
testRuntimeSpan<double>();
testRuntimeSpan<std::string>();
testRuntimeSpan<A>();
// TODO: Add some conversion tests here that aren't "X --> const X"
// assert((testConversionSpan<unsigned char, char>()));
checkCV();
}
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