cxx/test/utilities/function.objects/unord.hash/enum.pass.cpp

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//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
// <functional>
// make sure that we can hash enumeration values
// Not very portable
#include <__config>
#if _LIBCPP_STD_VER > 11
#include <functional>
#include <cassert>
#include <type_traits>
#include <limits>
enum class Colors { red, orange, yellow, green, blue, indigo, violet };
enum class Cardinals { zero, one, two, three, five=5 };
enum class LongColors : short { red, orange, yellow, green, blue, indigo, violet };
enum class ShortColors : long { red, orange, yellow, green, blue, indigo, violet };
enum class EightBitColors : uint8_t { red, orange, yellow, green, blue, indigo, violet };
enum Fruits { apple, pear, grape, mango, cantaloupe };
template <class T>
void
test()
{
static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
std::hash<T> >::value), "");
typedef typename std::underlying_type<T>::type under_type;
std::hash<T> h1;
std::hash<under_type> h2;
for (int i = 0; i <= 5; ++i)
{
T t(static_cast<T> (i));
if (sizeof(T) <= sizeof(std::size_t))
assert(h1(t) == h2(static_cast<under_type>(i)));
}
}
int main()
{
test<Cardinals>();
test<Colors>();
test<ShortColors>();
test<LongColors>();
test<EightBitColors>();
test<Fruits>();
}
#else
int main () {}
#endif