//===----------------------------------------------------------------------===//
//
// 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: !stdlib=libc++ && (c++03 || c++11 || c++14)

// <functional>

// template <class T>
// struct hash
// {
//     size_t operator()(T val) const;
// };

// Not very portable

#include <string_view>
#include <string>
#include <cassert>
#include <type_traits>

#include "test_macros.h"

using std::string_view;

template <class SV>
void test() {
  typedef std::hash<SV> H;
#if TEST_STD_VER <= 14
  static_assert((std::is_same<typename H::argument_type, SV>::value), "");
  static_assert((std::is_same<typename H::result_type, std::size_t>::value), "");
#endif

  typedef typename SV::value_type char_type;
  typedef std::basic_string<char_type> String;
  typedef std::hash<String> SH;
  ASSERT_NOEXCEPT(H()(SV()));

  char_type g1[10];
  char_type g2[10];
  for (int i = 0; i < 10; ++i)
    g1[i] = g2[9 - i] = static_cast<char_type>('0' + i);
  H h;
  SH sh;
  SV s1(g1, 10);
  String ss1(s1);
  SV s2(g2, 10);
  String ss2(s2);
  assert(h(s1) == h(s1));
  assert(h(s1) != h(s2));
  assert(sh(ss1) == h(s1));
  assert(sh(ss2) == h(s2));
}

int main(int, char**) {
  test<std::string_view>();
#ifndef TEST_HAS_NO_CHAR8_T
  test<std::u8string_view>();
#endif
  test<std::u16string_view>();
  test<std::u32string_view>();
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
  test<std::wstring_view>();
#endif

  return 0;
}