Class hash

tests/ordered_map_tests.cpp:1480–1488

Use a KeyEqual and Hash where any odd unsigned number 'x' is equal to 'x-1'. Make sure that KeyEqual is called (and not ==).

  // Use a KeyEqual and Hash where any odd unsigned number 'x' is equal to
  // 'x-1'. Make sure that KeyEqual is called (and not ==).
  struct hash {
    std::size_t operator()(std::uint64_t v) const {
      if (v % 2u == 1u) {
        return std::hash<std::uint64_t>()(v - 1);
      } else {
        return std::hash<std::uint64_t>()(v);
      }
    }
  };

  struct key_equal {
    bool operator()(std::uint64_t lhs, std::uint64_t rhs) const {