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// -*- C++ -*-
//===------------------------------ span ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <span>
// template<class Container>
// constexpr span(Container& cont);
// template<class Container>
// constexpr span(const Container& cont);
//
// Remarks: These constructors shall not participate in overload resolution unless:
// — Container is not a specialization of span,
// — Container is not a specialization of array,
// — is_array_v<Container> is false,
// — data(cont) and size(cont) are both well-formed, and
// — remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[].
//
#include <span>
#include <cassert>
#include <string>
#include <vector>
#include "test_macros.h"
// Look ma - I'm a container!
template <typename T>
struct IsAContainer {
constexpr IsAContainer() : v_{} {}
constexpr size_t size() const {return 1;}
constexpr T *data() {return &v_;}
constexpr const T *data() const {return &v_;}
constexpr T const *getV() const {return &v_;} // for checking
T v_;
};
void checkCV()
{
std::vector<int> v = {1,2,3};
// Types the same (dynamic sized)
{
std::span< int> s1{v}; // a span< int> pointing at int.
}
// Types the same (static sized)
{
std::span< int,3> s1{v}; // a span< int> pointing at int.
}
// types different (dynamic sized)
{
std::span<const int> s1{v}; // a span<const int> pointing at int.
std::span< volatile int> s2{v}; // a span< volatile int> pointing at int.
std::span< volatile int> s3{v}; // a span< volatile int> pointing at const int.
std::span<const volatile int> s4{v}; // a span<const volatile int> pointing at int.
}
// types different (static sized)
{
std::span<const int,3> s1{v}; // a span<const int> pointing at int.
std::span< volatile int,3> s2{v}; // a span< volatile int> pointing at int.
std::span< volatile int,3> s3{v}; // a span< volatile int> pointing at const int.
std::span<const volatile int,3> s4{v}; // a span<const volatile int> pointing at int.
}
}
template <typename T>
constexpr bool testConstexprSpan()
{
constexpr IsAContainer<const T> val{};
std::span<const T> s1{val};
std::span<const T, 1> s2{val};
return
s1.data() == val.getV() && s1.size() == 1
&& s2.data() == val.getV() && s2.size() == 1;
}
template <typename T>
void testRuntimeSpan()
{
IsAContainer<T> val{};
std::span<const T> s1{val};
std::span<const T, 1> s2{val};
assert(s1.data() == val.getV() && s1.size() == 1);
assert(s2.data() == val.getV() && s2.size() == 1);
}
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>();
checkCV();
}