[libc++] Remove cycle between <type_traits> and <cstddef>

This was caused by byte depending on traits. This patch moves
the minimal amount of meta-programming into <cstddef> to break the cycle.
This commit is contained in:
Eric Fiselier 2020-02-14 17:34:46 +01:00
parent 0d2ba6577d
commit cccf1ef0c8
2 changed files with 54 additions and 50 deletions

View File

@ -57,6 +57,32 @@ using ::max_align_t;
typedef long double max_align_t;
#endif
template <class _Tp> struct __libcpp_is_integral { enum { value = 0 }; };
template <> struct __libcpp_is_integral<bool> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<char> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<signed char> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<unsigned char> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<wchar_t> { enum { value = 1 }; };
#ifndef _LIBCPP_NO_HAS_CHAR8_T
template <> struct __libcpp_is_integral<char8_t> { enum { value = 1 }; };
#endif
#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
template <> struct __libcpp_is_integral<char16_t> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<char32_t> { enum { value = 1 }; };
#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
template <> struct __libcpp_is_integral<short> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<unsigned short> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<int> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<unsigned int> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<long> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<unsigned long> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<long long> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<unsigned long long> { enum { value = 1 }; };
#ifndef _LIBCPP_HAS_NO_INT128
template <> struct __libcpp_is_integral<__int128_t> { enum { value = 1 }; };
template <> struct __libcpp_is_integral<__uint128_t> { enum { value = 1 }; };
#endif
_LIBCPP_END_NAMESPACE_STD
#if _LIBCPP_STD_VER > 14
@ -64,6 +90,11 @@ namespace std // purposefully not versioned
{
enum class byte : unsigned char {};
template <bool> struct __enable_if_integral_imp {};
template <> struct __enable_if_integral_imp<true> { using type = byte; };
template <class _Tp> using _EnableByteOverload = typename __enable_if_integral_imp<__libcpp_is_integral<_Tp>::value>::type;
constexpr byte operator| (byte __lhs, byte __rhs) noexcept
{
return static_cast<byte>(
@ -104,10 +135,31 @@ constexpr byte operator~ (byte __b) noexcept
~static_cast<unsigned int>(__b)
));
}
template <class _Integer>
constexpr _EnableByteOverload<_Integer> &
operator<<=(byte& __lhs, _Integer __shift) noexcept
{ return __lhs = __lhs << __shift; }
template <class _Integer>
constexpr _EnableByteOverload<_Integer>
operator<< (byte __lhs, _Integer __shift) noexcept
{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) << __shift)); }
template <class _Integer>
constexpr _EnableByteOverload<_Integer> &
operator>>=(byte& __lhs, _Integer __shift) noexcept
{ return __lhs = __lhs >> __shift; }
template <class _Integer>
constexpr _EnableByteOverload<_Integer>
operator>> (byte __lhs, _Integer __shift) noexcept
{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) >> __shift)); }
template <class _Integer, class = _EnableByteOverload<_Integer> >
constexpr _Integer
to_integer(byte __b) noexcept { return static_cast<_Integer>(__b); }
}
#include <type_traits> // rest of byte
#endif
#endif // _LIBCPP_CSTDDEF

View File

@ -735,34 +735,8 @@ _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_null_pointer_v
// is_integral
template <class _Tp> struct __libcpp_is_integral : public false_type {};
template <> struct __libcpp_is_integral<bool> : public true_type {};
template <> struct __libcpp_is_integral<char> : public true_type {};
template <> struct __libcpp_is_integral<signed char> : public true_type {};
template <> struct __libcpp_is_integral<unsigned char> : public true_type {};
template <> struct __libcpp_is_integral<wchar_t> : public true_type {};
#ifndef _LIBCPP_NO_HAS_CHAR8_T
template <> struct __libcpp_is_integral<char8_t> : public true_type {};
#endif
#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
template <> struct __libcpp_is_integral<char16_t> : public true_type {};
template <> struct __libcpp_is_integral<char32_t> : public true_type {};
#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
template <> struct __libcpp_is_integral<short> : public true_type {};
template <> struct __libcpp_is_integral<unsigned short> : public true_type {};
template <> struct __libcpp_is_integral<int> : public true_type {};
template <> struct __libcpp_is_integral<unsigned int> : public true_type {};
template <> struct __libcpp_is_integral<long> : public true_type {};
template <> struct __libcpp_is_integral<unsigned long> : public true_type {};
template <> struct __libcpp_is_integral<long long> : public true_type {};
template <> struct __libcpp_is_integral<unsigned long long> : public true_type {};
#ifndef _LIBCPP_HAS_NO_INT128
template <> struct __libcpp_is_integral<__int128_t> : public true_type {};
template <> struct __libcpp_is_integral<__uint128_t> : public true_type {};
#endif
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
: public __libcpp_is_integral<typename remove_cv<_Tp>::type> {};
: public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
template <class _Tp>
@ -4046,29 +4020,7 @@ _LIBCPP_END_NAMESPACE_STD
// std::byte
namespace std // purposefully not versioned
{
template <class _Integer>
constexpr typename enable_if<is_integral_v<_Integer>, byte>::type &
operator<<=(byte& __lhs, _Integer __shift) noexcept
{ return __lhs = __lhs << __shift; }
template <class _Integer>
constexpr typename enable_if<is_integral_v<_Integer>, byte>::type
operator<< (byte __lhs, _Integer __shift) noexcept
{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) << __shift)); }
template <class _Integer>
constexpr typename enable_if<is_integral_v<_Integer>, byte>::type &
operator>>=(byte& __lhs, _Integer __shift) noexcept
{ return __lhs = __lhs >> __shift; }
template <class _Integer>
constexpr typename enable_if<is_integral_v<_Integer>, byte>::type
operator>> (byte __lhs, _Integer __shift) noexcept
{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) >> __shift)); }
template <class _Integer>
constexpr typename enable_if<is_integral_v<_Integer>, _Integer>::type
to_integer(byte __b) noexcept { return static_cast<_Integer>(__b); }
}
#endif