llvm/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/find.pass.cpp

//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

// <string>

// template<> struct char_traits<char16_t>

// static const char_type* find(const char_type* s, size_t n, const char_type& a);
// constexpr in C++17

#include <string>
#include <cassert>

#include "test_macros.h"

#if TEST_STD_VER > 14
constexpr bool test_constexpr() {
  constexpr const char16_t* p = u"123";
  return std::char_traits<char16_t>::find(p, 3, u'1') == p && std::char_traits<char16_t>::find(p, 3, u'2') == p + 1 &&
         std::char_traits<char16_t>::find(p, 3, u'3') == p + 2 &&
         std::char_traits<char16_t>::find(p, 3, u'4') == nullptr;
}
#endif

int main(int, char**) {
  char16_t s1[] = {1, 2, 3};
  assert(std::char_traits<char16_t>::find(s1, 3, char16_t(1)) == s1);
  assert(std::char_traits<char16_t>::find(s1, 3, char16_t(2)) == s1 + 1);
  assert(std::char_traits<char16_t>::find(s1, 3, char16_t(3)) == s1 + 2);
  assert(std::char_traits<char16_t>::find(s1, 3, char16_t(4)) == 0);
  assert(std::char_traits<char16_t>::find(s1, 3, char16_t(0)) == 0);
  assert(std::char_traits<char16_t>::find(NULL, 0, char16_t(0)) == 0);

#if TEST_STD_VER > 14
  static_assert(test_constexpr(), "");
#endif

  return 0;
}