test/std/strings/string.view/string.view.template/starts_with.ptr.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 svNot{"def", 3};

    LIBCPP_ASSERT_NOEXCEPT(sv0.starts_with(""));

    assert(sv0.starts_with(""));
    assert(!sv0.starts_with("a"));

    assert(sv1.starts_with(""));
    assert(sv1.starts_with("a"));
    assert(!sv1.starts_with("ab"));
    assert(!sv1.starts_with("abc"));
    assert(!sv1.starts_with("abcd"));
    assert(!sv1.starts_with("abcde"));
    assert(!sv1.starts_with("def"));

    assert(sv2.starts_with(s + 5));
    assert(sv2.starts_with("a"));
    assert(sv2.starts_with("ab"));
    assert(!sv2.starts_with("abc"));
    assert(!sv2.starts_with("abcd"));
    assert(!sv2.starts_with("abcde"));
    assert(!sv2.starts_with("def"));

    assert(svNot.starts_with(""));
    assert(!svNot.starts_with("a"));
    assert(!svNot.starts_with("ab"));
    assert(!svNot.starts_with("abc"));
    assert(!svNot.starts_with("abcd"));
    assert(!svNot.starts_with("abcde"));
    assert(svNot.starts_with("def"));
  }

#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 svNot{"def", 3};

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

    static_assert(sv1.starts_with(""), "");
    static_assert(sv1.starts_with("a"), "");
    static_assert(!sv1.starts_with("ab"), "");
    static_assert(!sv1.starts_with("abc"), "");
    static_assert(!sv1.starts_with("abcd"), "");
    static_assert(!sv1.starts_with("abcde"), "");
    static_assert(!sv1.starts_with("def"), "");

    static_assert(sv2.starts_with(s + 5), "");
    static_assert(sv2.starts_with("a"), "");
    static_assert(sv2.starts_with("ab"), "");
    static_assert(!sv2.starts_with("abc"), "");
    static_assert(!sv2.starts_with("abcd"), "");
    static_assert(!sv2.starts_with("abcde"), "");
    static_assert(!sv2.starts_with("def"), "");

    static_assert(svNot.starts_with(""), "");
    static_assert(!svNot.starts_with("a"), "");
    static_assert(!svNot.starts_with("ab"), "");
    static_assert(!svNot.starts_with("abc"), "");
    static_assert(!svNot.starts_with("abcd"), "");
    static_assert(!svNot.starts_with("abcde"), "");
    static_assert(svNot.starts_with("def"), "");
  }
#endif

  return 0;
}