//===----------------------------------------------------------------------===//
//
// 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<class InputIterator>
//   basic_string& append(InputIterator first, InputIterator last); // constexpr since C++20

#include <string>
#include <cassert>

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

template <class S, class It>
TEST_CONSTEXPR_CXX20 void
test(S s, It first, It last, S expected)
{
    s.append(first, last);
    LIBCPP_ASSERT(s.__invariants());
    assert(s == expected);
}

#ifndef TEST_HAS_NO_EXCEPTIONS
struct Widget { operator char() const { throw 42; } };

template <class S, class It>
TEST_CONSTEXPR_CXX20 void
test_exceptions(S s, It first, It last)
{
    S original = s;
    typename S::iterator begin = s.begin();
    typename S::iterator end = s.end();

    try {
        s.append(first, last);
        assert(false);
    } catch (...) {}

    // Part of "no effects" is that iterators and pointers
    // into the string must not have been invalidated.
    LIBCPP_ASSERT(s.__invariants());
    assert(s == original);
    assert(s.begin() == begin);
    assert(s.end() == end);
}
#endif

template <class S>
TEST_CONSTEXPR_CXX20 void test_string() {
  const char* s = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  test(S(), s, s, S());
  test(S(), s, s+1, S("A"));
  test(S(), s, s+10, S("ABCDEFGHIJ"));
  test(S(), s, s+52, S("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("12345"), s, s, S("12345"));
  test(S("12345"), s, s+1, S("12345A"));
  test(S("12345"), s, s+10, S("12345ABCDEFGHIJ"));
  test(S("12345"), s, s+52, S("12345ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("1234567890"), s, s, S("1234567890"));
  test(S("1234567890"), s, s+1, S("1234567890A"));
  test(S("1234567890"), s, s+10, S("1234567890ABCDEFGHIJ"));
  test(S("1234567890"), s, s+52, S("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("12345678901234567890"), s, s, S("12345678901234567890"));
  test(S("12345678901234567890"), s, s+1, S("12345678901234567890""A"));
  test(S("12345678901234567890"), s, s+10, S("12345678901234567890""ABCDEFGHIJ"));
  test(S("12345678901234567890"), s, s+52,
      S("12345678901234567890""ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S(), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s), S());
  test(S(), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+1), S("A"));
  test(S(), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+10),
      S("ABCDEFGHIJ"));
  test(S(), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+52),
      S("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("12345"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s),
      S("12345"));
  test(S("12345"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+1),
      S("12345A"));
  test(S("12345"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+10),
      S("12345ABCDEFGHIJ"));
  test(S("12345"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+52),
      S("12345ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("1234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s),
      S("1234567890"));
  test(S("1234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+1),
      S("1234567890A"));
  test(S("1234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+10),
      S("1234567890ABCDEFGHIJ"));
  test(S("1234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+52),
      S("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));

  test(S("12345678901234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s),
      S("12345678901234567890"));
  test(S("12345678901234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+1),
      S("12345678901234567890""A"));
  test(S("12345678901234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+10),
      S("12345678901234567890""ABCDEFGHIJ"));
  test(S("12345678901234567890"), cpp17_input_iterator<const char*>(s), cpp17_input_iterator<const char*>(s+52),
      S("12345678901234567890""ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"));
}

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

#ifndef TEST_HAS_NO_EXCEPTIONS
  if (!TEST_IS_CONSTANT_EVALUATED) { // test iterator operations that throw
    typedef std::string S;
    typedef ThrowingIterator<char> TIter;
    typedef cpp17_input_iterator<TIter> IIter;
    const char* s = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    test_exceptions(S(), IIter(TIter(s, s+10, 4, TIter::TAIncrement)), IIter(TIter()));
    test_exceptions(S(), IIter(TIter(s, s+10, 5, TIter::TADereference)), IIter(TIter()));
    test_exceptions(S(), IIter(TIter(s, s+10, 6, TIter::TAComparison)), IIter(TIter()));

    test_exceptions(S(), TIter(s, s+10, 4, TIter::TAIncrement), TIter());
    test_exceptions(S(), TIter(s, s+10, 5, TIter::TADereference), TIter());
    test_exceptions(S(), TIter(s, s+10, 6, TIter::TAComparison), TIter());

    Widget w[100];
    test_exceptions(S(), w, w+100);
  }
#endif

  { // test appending to self
    typedef std::string S;
    S s_short = "123/";
    S s_long  = "Lorem ipsum dolor sit amet, consectetur/";

    s_short.append(s_short.begin(), s_short.end());
    assert(s_short == "123/123/");
    s_short.append(s_short.begin(), s_short.end());
    assert(s_short == "123/123/123/123/");
    s_short.append(s_short.begin(), s_short.end());
    assert(s_short == "123/123/123/123/123/123/123/123/");

    s_long.append(s_long.begin(), s_long.end());
    assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
  }

  { // test appending a different type
    typedef std::string S;
    const std::uint8_t p[] = "ABCD";

    S s;
    s.append(p, p + 4);
    assert(s == "ABCD");
  }

  { // regression-test appending to self in sneaky ways
    std::string s_short = "hello";
    std::string s_long = "Lorem ipsum dolor sit amet, consectetur/";
    std::string s_othertype = "hello";
    std::string s_sneaky = "hello";

    test(s_short, s_short.data() + s_short.size(), s_short.data() + s_short.size() + 1,
         std::string("hello\0", 6));
    test(s_long, s_long.data() + s_long.size(), s_long.data() + s_long.size() + 1,
         std::string("Lorem ipsum dolor sit amet, consectetur/\0", 41));

    s_sneaky.reserve(12);
    test(s_sneaky, s_sneaky.data(), s_sneaky.data() + 6, std::string("hellohello\0", 11));

     if (!TEST_IS_CONSTANT_EVALUATED) {
       const unsigned char *first = reinterpret_cast<const unsigned char*>(s_othertype.data());
       test(s_othertype, first + 2, first + 5, std::string("hellollo"));
     }
  }

  { // test with a move iterator that returns char&&
    typedef forward_iterator<const char*> It;
    typedef std::move_iterator<It> MoveIt;
    const char p[] = "ABCD";
    std::string s;
    s.append(MoveIt(It(std::begin(p))), MoveIt(It(std::end(p) - 1)));
    assert(s == "ABCD");
  }
  { // test with a move iterator that returns char&&
    typedef const char* It;
    typedef std::move_iterator<It> MoveIt;
    const char p[] = "ABCD";
    std::string s;
    s.append(MoveIt(It(std::begin(p))), MoveIt(It(std::end(p) - 1)));
    assert(s == "ABCD");
  }

  return true;
}

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

  return 0;
}