test/std/strings/string.view/string.view.modifiers/clear.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//


// <string_view>

// void clear() noexcept

#include <string_view>
#include <cassert>

#include "test_macros.h"

template<typename CharT>
void test ( const CharT *s, size_t len ) {
    typedef std::basic_string_view<CharT> SV;
    {
    SV sv1 ( s );
    assert ( sv1.size() == len );
    assert ( sv1.data() == s );

    sv1.clear ();
    assert ( sv1.data() == nullptr );
    assert ( sv1.size() == 0 );
    assert ( sv1 == SV());
    }
}

#if _LIBCPP_STD_VER > 11
constexpr size_t test_ce ( size_t n ) {
    typedef std::basic_string_view<char> SV;
    SV sv1{ "ABCDEFGHIJKL", n };
    sv1.clear();
    return sv1.size();
}
#endif

int main () {
    test ( "ABCDE", 5 );
    test ( "a", 1 );
    test ( "", 0 );

    test ( L"ABCDE", 5 );
    test ( L"a", 1 );
    test ( L"", 0 );

#if TEST_STD_VER >= 11
    test ( u"ABCDE", 5 );
    test ( u"a", 1 );
    test ( u"", 0 );

    test ( U"ABCDE", 5 );
    test ( U"a", 1 );
    test ( U"", 0 );
#endif

#if _LIBCPP_STD_VER > 11
    static_assert ( test_ce (5) == 0, "" );
#endif

}