//===----------------------------------------------------------------------===//
//
// 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>

// size_type copy(charT* s, size_type n, size_type pos = 0) const; // constexpr since C++20

#include <string>
#include <stdexcept>
#include <algorithm>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

template <class S>
TEST_CONSTEXPR_CXX20 void
test(S str, typename S::value_type* s, typename S::size_type n,
     typename S::size_type pos)
{
    const S& cs = str;
    if (pos <= cs.size())
    {
        typename S::size_type r = cs.copy(s, n, pos);
        typename S::size_type rlen = std::min(n, cs.size() - pos);
        assert(r == rlen);
        for (r = 0; r < rlen; ++r)
            assert(S::traits_type::eq(cs[pos+r], s[r]));
    }
#ifndef TEST_HAS_NO_EXCEPTIONS
    else if (!TEST_IS_CONSTANT_EVALUATED)
    {
        try
        {
            typename S::size_type r = cs.copy(s, n, pos);
            ((void)r); // Prevent unused warning
            assert(false);
        }
        catch (std::out_of_range&)
        {
            assert(pos > str.size());
        }
    }
#endif
}

template <class S>
TEST_CONSTEXPR_CXX20 void test_string() {
  char s[50];
  test(S(""), s, 0, 0);
  test(S(""), s, 0, 1);
  test(S(""), s, 1, 0);
  test(S("abcde"), s, 0, 0);
  test(S("abcde"), s, 0, 1);
  test(S("abcde"), s, 0, 2);
  test(S("abcde"), s, 0, 4);
  test(S("abcde"), s, 0, 5);
  test(S("abcde"), s, 0, 6);
  test(S("abcde"), s, 1, 0);
  test(S("abcde"), s, 1, 1);
  test(S("abcde"), s, 1, 2);
  test(S("abcde"), s, 1, 4);
  test(S("abcde"), s, 1, 5);
  test(S("abcde"), s, 2, 0);
  test(S("abcde"), s, 2, 1);
  test(S("abcde"), s, 2, 2);
  test(S("abcde"), s, 2, 4);
  test(S("abcde"), s, 4, 0);
  test(S("abcde"), s, 4, 1);
  test(S("abcde"), s, 4, 2);
  test(S("abcde"), s, 5, 0);
  test(S("abcde"), s, 5, 1);
  test(S("abcde"), s, 6, 0);
  test(S("abcdefghijklmnopqrst"), s, 0, 0);
  test(S("abcdefghijklmnopqrst"), s, 0, 1);
  test(S("abcdefghijklmnopqrst"), s, 0, 2);
  test(S("abcdefghijklmnopqrst"), s, 0, 10);
  test(S("abcdefghijklmnopqrst"), s, 0, 19);
  test(S("abcdefghijklmnopqrst"), s, 0, 20);
  test(S("abcdefghijklmnopqrst"), s, 0, 21);
  test(S("abcdefghijklmnopqrst"), s, 1, 0);
  test(S("abcdefghijklmnopqrst"), s, 1, 1);
  test(S("abcdefghijklmnopqrst"), s, 1, 2);
  test(S("abcdefghijklmnopqrst"), s, 1, 9);
  test(S("abcdefghijklmnopqrst"), s, 1, 18);
  test(S("abcdefghijklmnopqrst"), s, 1, 19);
  test(S("abcdefghijklmnopqrst"), s, 1, 20);
  test(S("abcdefghijklmnopqrst"), s, 2, 0);
  test(S("abcdefghijklmnopqrst"), s, 2, 1);
  test(S("abcdefghijklmnopqrst"), s, 2, 2);
  test(S("abcdefghijklmnopqrst"), s, 2, 9);
  test(S("abcdefghijklmnopqrst"), s, 2, 17);
  test(S("abcdefghijklmnopqrst"), s, 2, 18);
  test(S("abcdefghijklmnopqrst"), s, 2, 19);
  test(S("abcdefghijklmnopqrst"), s, 10, 0);
  test(S("abcdefghijklmnopqrst"), s, 10, 1);
  test(S("abcdefghijklmnopqrst"), s, 10, 2);
  test(S("abcdefghijklmnopqrst"), s, 10, 5);
  test(S("abcdefghijklmnopqrst"), s, 10, 9);
  test(S("abcdefghijklmnopqrst"), s, 10, 10);
  test(S("abcdefghijklmnopqrst"), s, 10, 11);
  test(S("abcdefghijklmnopqrst"), s, 19, 0);
  test(S("abcdefghijklmnopqrst"), s, 19, 1);
  test(S("abcdefghijklmnopqrst"), s, 19, 2);
  test(S("abcdefghijklmnopqrst"), s, 20, 0);
  test(S("abcdefghijklmnopqrst"), s, 20, 1);
  test(S("abcdefghijklmnopqrst"), s, 21, 0);
}

TEST_CONSTEXPR_CXX20 bool test() {
  test_string<std::string>();
#if TEST_STD_VER >= 11
  test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();
#endif

  return true;
}

int main(int, char**)
{
  test();
#if TEST_STD_VER > 17
  static_assert(test());
#endif

  return 0;
}