1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___TYPE_TRAITS_IS_UNSIGNED_H
10 #define _LIBCPP___TYPE_TRAITS_IS_UNSIGNED_H
11 
12 #include <__config>
13 #include <__type_traits/integral_constant.h>
14 #include <__type_traits/is_arithmetic.h>
15 #include <__type_traits/is_integral.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_BEGIN_NAMESPACE_STD
22 
23 // Before AppleClang 14, __is_unsigned returned true for enums with signed underlying type.
24 #if __has_builtin(__is_unsigned) && !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1400)
25 
26 template<class _Tp>
27 struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
28 
29 #if _LIBCPP_STD_VER > 14
30 template <class _Tp>
31 inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
32 #endif
33 
34 #else // __has_builtin(__is_unsigned)
35 
36 template <class _Tp, bool = is_integral<_Tp>::value>
37 struct __libcpp_is_unsigned_impl : public _BoolConstant<(_Tp(0) < _Tp(-1))> {};
38 
39 template <class _Tp>
40 struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
41 
42 template <class _Tp, bool = is_arithmetic<_Tp>::value>
43 struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
44 
45 template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
46 
47 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
48 
49 #if _LIBCPP_STD_VER > 14
50 template <class _Tp>
51 inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
52 #endif
53 
54 #endif // __has_builtin(__is_unsigned)
55 
56 _LIBCPP_END_NAMESPACE_STD
57 
58 #endif // _LIBCPP___TYPE_TRAITS_IS_UNSIGNED_H
59