Cleanups: Follow Standard order for byteswap in <bit> (#3543)

microsoft · Mar 7, 2023 · 1ab51c6 · 1ab51c6
1 parent 0c16581
commit 1ab51c6
Showing 1 changed file with 43 additions and 45 deletions.
diff --git a/stl/inc/bit b/stl/inc/bit
@@ -34,6 +34,49 @@ _NODISCARD constexpr _To bit_cast(const _From& _Val) noexcept {
     return __builtin_bit_cast(_To, _Val);
 }
 
+#if _HAS_CXX23
+_NODISCARD constexpr unsigned short _Byteswap_ushort(const unsigned short _Val) noexcept {
+    if (_STD is_constant_evaluated()) {
+        return static_cast<unsigned short>((_Val << 8) | (_Val >> 8));
+    } else {
+        return _byteswap_ushort(_Val);
+    }
+}
+
+_NODISCARD constexpr unsigned long _Byteswap_ulong(const unsigned long _Val) noexcept {
+    if (_STD is_constant_evaluated()) {
+        return (_Val << 24) | ((_Val << 8) & 0x00FF'0000) | ((_Val >> 8) & 0x0000'FF00) | (_Val >> 24);
+    } else {
+        return _byteswap_ulong(_Val);
+    }
+}
+
+_NODISCARD constexpr unsigned long long _Byteswap_uint64(const unsigned long long _Val) noexcept {
+    if (_STD is_constant_evaluated()) {
+        return (_Val << 56) | ((_Val << 40) & 0x00FF'0000'0000'0000) | ((_Val << 24) & 0x0000'FF00'0000'0000)
+             | ((_Val << 8) & 0x0000'00FF'0000'0000) | ((_Val >> 8) & 0x0000'0000'FF00'0000)
+             | ((_Val >> 24) & 0x0000'0000'00FF'0000) | ((_Val >> 40) & 0x0000'0000'0000'FF00) | (_Val >> 56);
+    } else {
+        return _byteswap_uint64(_Val);
+    }
+}
+
+_EXPORT_STD template <class _Ty, enable_if_t<is_integral_v<_Ty>, int> = 0>
+_NODISCARD constexpr _Ty byteswap(const _Ty _Val) noexcept {
+    if constexpr (sizeof(_Ty) == 1) {
+        return _Val;
+    } else if constexpr (sizeof(_Ty) == 2) {
+        return static_cast<_Ty>(_Byteswap_ushort(static_cast<unsigned short>(_Val)));
+    } else if constexpr (sizeof(_Ty) == 4) {
+        return static_cast<_Ty>(_Byteswap_ulong(static_cast<unsigned long>(_Val)));
+    } else if constexpr (sizeof(_Ty) == 8) {
+        return static_cast<_Ty>(_Byteswap_uint64(static_cast<unsigned long long>(_Val)));
+    } else {
+        static_assert(_Always_false<_Ty>, "Unexpected integer size");
+    }
+}
+#endif // _HAS_CXX23
+
 _EXPORT_STD template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
 _NODISCARD constexpr int countl_zero(_Ty _Val) noexcept;
 
@@ -261,34 +304,6 @@ _NODISCARD int _Checked_arm_arm64_countl_zero(const _Ty _Val) noexcept {
 }
 #endif // defined(_M_ARM) || defined(_M_ARM64)
 
-#if _HAS_CXX23
-_NODISCARD constexpr unsigned short _Byteswap_ushort(const unsigned short _Val) noexcept {
-    if (_STD is_constant_evaluated()) {
-        return static_cast<unsigned short>((_Val << 8) | (_Val >> 8));
-    } else {
-        return _byteswap_ushort(_Val);
-    }
-}
-
-_NODISCARD constexpr unsigned long _Byteswap_ulong(const unsigned long _Val) noexcept {
-    if (_STD is_constant_evaluated()) {
-        return (_Val << 24) | ((_Val << 8) & 0x00FF'0000) | ((_Val >> 8) & 0x0000'FF00) | (_Val >> 24);
-    } else {
-        return _byteswap_ulong(_Val);
-    }
-}
-
-_NODISCARD constexpr unsigned long long _Byteswap_uint64(const unsigned long long _Val) noexcept {
-    if (_STD is_constant_evaluated()) {
-        return (_Val << 56) | ((_Val << 40) & 0x00FF'0000'0000'0000) | ((_Val << 24) & 0x0000'FF00'0000'0000)
-             | ((_Val << 8) & 0x0000'00FF'0000'0000) | ((_Val >> 8) & 0x0000'0000'FF00'0000)
-             | ((_Val >> 24) & 0x0000'0000'00FF'0000) | ((_Val >> 40) & 0x0000'0000'0000'FF00) | (_Val >> 56);
-    } else {
-        return _byteswap_uint64(_Val);
-    }
-}
-#endif // _HAS_CXX23
-
 _EXPORT_STD template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> /* = 0 */>
 _NODISCARD constexpr int countl_zero(const _Ty _Val) noexcept {
 #if defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
@@ -324,23 +339,6 @@ _NODISCARD constexpr int popcount(const _Ty _Val) noexcept {
     return _Popcount(_Val);
 }
 
-#if _HAS_CXX23
-_EXPORT_STD template <class _Ty, enable_if_t<is_integral_v<_Ty>, int> = 0>
-_NODISCARD constexpr _Ty byteswap(const _Ty _Val) noexcept {
-    if constexpr (sizeof(_Ty) == 1) {
-        return _Val;
-    } else if constexpr (sizeof(_Ty) == 2) {
-        return static_cast<_Ty>(_Byteswap_ushort(static_cast<unsigned short>(_Val)));
-    } else if constexpr (sizeof(_Ty) == 4) {
-        return static_cast<_Ty>(_Byteswap_ulong(static_cast<unsigned long>(_Val)));
-    } else if constexpr (sizeof(_Ty) == 8) {
-        return static_cast<_Ty>(_Byteswap_uint64(static_cast<unsigned long long>(_Val)));
-    } else {
-        static_assert(_Always_false<_Ty>, "Unexpected integer size");
-    }
-}
-#endif // _HAS_CXX23
-
 _EXPORT_STD enum class endian { little = 0, big = 1, native = little };
 
 _STD_END