libcxx/test/std/strings/basic.string.hash/strings.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <functional>
  10
  11 // template <class T>
  12 // struct hash
  13 //     : public unary_function<T, size_t>
  14 // {
  15 //     size_t operator()(T val) const;
  16 // };
  17
  18 // Not very portable
  19
  20 #include <string>
  21 #include <cassert>
  22 #include <type_traits>
  23
  24 #include "test_macros.h"
  25
  26 template <class T>
  27 void
  28 test()
  29 {
  30     typedef std::hash<T> H;
  31     static_assert((std::is_same<typename H::argument_type, T>::value), "" );
  32     static_assert((std::is_same<typename H::result_type, std::size_t>::value), "" );
  33     ASSERT_NOEXCEPT(H()(T()));
  34
  35     H h;
  36     std::string g1 = "1234567890";
  37     std::string g2 = "1234567891";
  38     T s1(g1.begin(), g1.end());
  39     T s2(g2.begin(), g2.end());
  40     assert(h(s1) != h(s2));
  41 }
  42
  43 int main(int, char**)
  44 {
  45     test<std::string>();
  46 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
  47     test<std::u8string>();
  48 #endif
  49 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
  50     test<std::u16string>();
  51     test<std::u32string>();
  52 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
  53     test<std::wstring>();
  54
  55   return 0;
  56 }