test/std/strings/string.view/string.view.template/starts_with.string_view.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
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14, c++17

// <string_view>

//   constexpr bool starts_with(string_view x) const noexcept;

#include <string_view>
#include <cassert>

#include "test_macros.h"
#include "constexpr_char_traits.h"

int main(int, char**) {
  {
    typedef std::string_view SV;
    const char* s = "abcde";
    SV sv0{};
    SV sv1{s, 1};
    SV sv2{s, 2};
    SV sv3{s, 3};
    SV sv4{s, 4};
    SV sv5{s, 5};
    SV svNot{"def", 3};

    ASSERT_NOEXCEPT(sv0.starts_with(sv0));

    assert(sv0.starts_with(sv0));
    assert(!sv0.starts_with(sv1));

    assert(sv1.starts_with(sv0));
    assert(sv1.starts_with(sv1));
    assert(!sv1.starts_with(sv2));
    assert(!sv1.starts_with(sv3));
    assert(!sv1.starts_with(sv4));
    assert(!sv1.starts_with(sv5));
    assert(!sv1.starts_with(svNot));

    assert(sv2.starts_with(sv0));
    assert(sv2.starts_with(sv1));
    assert(sv2.starts_with(sv2));
    assert(!sv2.starts_with(sv3));
    assert(!sv2.starts_with(sv4));
    assert(!sv2.starts_with(sv5));
    assert(!sv2.starts_with(svNot));

    assert(svNot.starts_with(sv0));
    assert(!svNot.starts_with(sv1));
    assert(!svNot.starts_with(sv2));
    assert(!svNot.starts_with(sv3));
    assert(!svNot.starts_with(sv4));
    assert(!svNot.starts_with(sv5));
    assert(svNot.starts_with(svNot));
  }

#if TEST_STD_VER > 11
  {
    typedef std::basic_string_view<char, constexpr_char_traits<char>> SV;
    constexpr const char* s = "abcde";
    constexpr SV sv0{};
    constexpr SV sv1{s, 1};
    constexpr SV sv2{s, 2};
    constexpr SV sv3{s, 3};
    constexpr SV sv4{s, 4};
    constexpr SV sv5{s, 5};
    constexpr SV svNot{"def", 3};

    static_assert(sv0.starts_with(sv0), "");
    static_assert(!sv0.starts_with(sv1), "");

    static_assert(sv1.starts_with(sv0), "");
    static_assert(sv1.starts_with(sv1), "");
    static_assert(!sv1.starts_with(sv2), "");
    static_assert(!sv1.starts_with(sv3), "");
    static_assert(!sv1.starts_with(sv4), "");
    static_assert(!sv1.starts_with(sv5), "");
    static_assert(!sv1.starts_with(svNot), "");

    static_assert(sv2.starts_with(sv0), "");
    static_assert(sv2.starts_with(sv1), "");
    static_assert(sv2.starts_with(sv2), "");
    static_assert(!sv2.starts_with(sv3), "");
    static_assert(!sv2.starts_with(sv4), "");
    static_assert(!sv2.starts_with(sv5), "");
    static_assert(!sv2.starts_with(svNot), "");

    static_assert(svNot.starts_with(sv0), "");
    static_assert(!svNot.starts_with(sv1), "");
    static_assert(!svNot.starts_with(sv2), "");
    static_assert(!svNot.starts_with(sv3), "");
    static_assert(!svNot.starts_with(sv4), "");
    static_assert(!svNot.starts_with(sv5), "");
    static_assert(svNot.starts_with(svNot), "");
  }
#endif

  return 0;
}