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

// <codecvt>

// template <class Elem, unsigned long Maxcode = 0x10ffff,
//           codecvt_mode Mode = (codecvt_mode)0>
// class codecvt_utf8_utf16
//     : public codecvt<Elem, char, mbstate_t>
// {
//     // unspecified
// };

// result
//     in(stateT& state,
//        const externT* from, const externT* from_end, const externT*& from_next,
//        internT* to, internT* to_end, internT*& to_next) const;

#include <codecvt>
#include <cassert>

template <class CharT, size_t = sizeof(CharT)>
struct TestHelper;
template <class CharT>
struct TestHelper<CharT, 2> {
  static void test();
};
template <class CharT>
struct TestHelper<CharT, 4> {
  static void test();
};

template <class CharT>
void TestHelper<CharT, 2>::test() {
  {
    typedef std::codecvt_utf8_utf16<CharT, 0x1000> C;
    C c;
    CharT w[2] = {0};
    char n[4] = {char(0xF1), char(0x80), char(0x80), char(0x83)};
    CharT* wp = nullptr;
    std::mbstate_t m;
    const char* np = nullptr;
    std::codecvt_base::result r = c.in(m, n, n + 4, np, w, w + 2, wp);
    assert(r == std::codecvt_base::error);
    assert(wp == w);
    assert(np == n);

    n[0] = char(0xE1);
    n[1] = char(0x80);
    n[2] = char(0x85);
    r = c.in(m, n, n + 3, np, w, w + 2, wp);
    assert(r == std::codecvt_base::error);
    assert(wp == w);
    assert(np == n);

    n[0] = char(0xD1);
    n[1] = char(0x93);
    r = c.in(m, n, n + 2, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 2);
    assert(w[0] == 0x0453);

    n[0] = char(0x56);
    r = c.in(m, n, n + 1, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 1);
    assert(w[0] == 0x0056);
  }
  {
    typedef std::codecvt_utf8_utf16<CharT, 0x10ffff, std::consume_header> C;
    C c;
    CharT w[2] = {0};
    char n[7] = {char(0xEF), char(0xBB), char(0xBF), char(0xF1),
                 char(0x80), char(0x80), char(0x83)};
    CharT* wp = nullptr;
    std::mbstate_t m;
    const char* np = nullptr;
    std::codecvt_base::result r = c.in(m, n, n + 7, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 2);
    assert(np == n + 7);
    assert(w[0] == 0xD8C0);
    assert(w[1] == 0xDC03);

    n[0] = char(0xE1);
    n[1] = char(0x80);
    n[2] = char(0x85);
    r = c.in(m, n, n + 3, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 3);
    assert(w[0] == 0x1005);

    n[0] = char(0xD1);
    n[1] = char(0x93);
    r = c.in(m, n, n + 2, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 2);
    assert(w[0] == 0x0453);

    n[0] = char(0x56);
    r = c.in(m, n, n + 1, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 1);
    assert(w[0] == 0x0056);
  }
}

template <class CharT>
void TestHelper<CharT, 4>::test() {
  {
    typedef std::codecvt_utf8_utf16<CharT> C;
    C c;
    CharT w[2] = {0};
    char n[4] = {char(0xF1), char(0x80), char(0x80), char(0x83)};
    CharT* wp = nullptr;
    std::mbstate_t m;
    const char* np = nullptr;
    std::codecvt_base::result r = c.in(m, n, n + 4, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 2);
    assert(np == n + 4);
    assert(w[0] == 0xD8C0);
    assert(w[1] == 0xDC03);

    n[0] = char(0xE1);
    n[1] = char(0x80);
    n[2] = char(0x85);
    r = c.in(m, n, n + 3, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 3);
    assert(w[0] == 0x1005);

    n[0] = char(0xD1);
    n[1] = char(0x93);
    r = c.in(m, n, n + 2, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 2);
    assert(w[0] == 0x0453);

    n[0] = char(0x56);
    r = c.in(m, n, n + 1, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 1);
    assert(w[0] == 0x0056);
  }
  {
    typedef std::codecvt_utf8_utf16<CharT, 0x1000> C;
    C c;
    CharT w[2] = {0};
    char n[4] = {char(0xF1), char(0x80), char(0x80), char(0x83)};
    CharT* wp = nullptr;
    std::mbstate_t m;
    const char* np = nullptr;
    std::codecvt_base::result r = c.in(m, n, n + 4, np, w, w + 2, wp);
    assert(r == std::codecvt_base::error);
    assert(wp == w);
    assert(np == n);

    n[0] = char(0xE1);
    n[1] = char(0x80);
    n[2] = char(0x85);
    r = c.in(m, n, n + 3, np, w, w + 2, wp);
    assert(r == std::codecvt_base::error);
    assert(wp == w);
    assert(np == n);

    n[0] = char(0xD1);
    n[1] = char(0x93);
    r = c.in(m, n, n + 2, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 2);
    assert(w[0] == 0x0453);

    n[0] = char(0x56);
    r = c.in(m, n, n + 1, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 1);
    assert(w[0] == 0x0056);
  }
  {
    typedef std::codecvt_utf8_utf16<CharT, 0x10ffff, std::consume_header> C;
    C c;
    CharT w[2] = {0};
    char n[7] = {char(0xEF), char(0xBB), char(0xBF), char(0xF1),
                 char(0x80), char(0x80), char(0x83)};
    CharT* wp = nullptr;
    std::mbstate_t m;
    const char* np = nullptr;
    std::codecvt_base::result r = c.in(m, n, n + 7, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 2);
    assert(np == n + 7);
    assert(w[0] == 0xD8C0);
    assert(w[1] == 0xDC03);

    n[0] = char(0xE1);
    n[1] = char(0x80);
    n[2] = char(0x85);
    r = c.in(m, n, n + 3, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 3);
    assert(w[0] == 0x1005);

    n[0] = char(0xD1);
    n[1] = char(0x93);
    r = c.in(m, n, n + 2, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 2);
    assert(w[0] == 0x0453);

    n[0] = char(0x56);
    r = c.in(m, n, n + 1, np, w, w + 2, wp);
    assert(r == std::codecvt_base::ok);
    assert(wp == w + 1);
    assert(np == n + 1);
    assert(w[0] == 0x0056);
  }
}

int main(int, char**) {
#ifndef _WIN32
  TestHelper<wchar_t>::test();
#endif
  TestHelper<char32_t>::test();
  TestHelper<char16_t>::test();

  return 0;
}