Fix the UUID structure

util/misc/uuid.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_UTIL_MISC_UUID_H_
 #define CRASHPAD_UTIL_MISC_UUID_H_
 
 #include <stdint.h>
 
 #include <string>
 
 namespace crashpad {
 
 //! \brief A universally unique identifier (%UUID).
 //!
 //! An alternate term for %UUID is “globally unique identifier” (GUID), used
 //! primarily by Microsoft.
 //!
 //! A %UUID is a unique 128-bit number specified by RFC 4122.
-//!
-//! This is a standard-layout structure, and it is acceptable to use `memcpy()`
-//! to set its value.
 struct UUID {
   //! \brief Initializes the %UUID to zero.
   UUID();
 
+  //! \copydoc InitializeFromBytes()
+  explicit UUID(const uint8_t* bytes);
+
   //! \brief Initializes the %UUID from a sequence of bytes.
   //!
+  //! \a bytes is taken as a %UUID laid out in big-endian format in memory. On
+  //! little-endian machines, appropriate byte-swapping will be performed to
+  //! initialize an object’s data members.
+  //!
   //! \param[in] bytes A buffer of exactly 16 bytes that will be assigned to the
   //!     %UUID.
-  explicit UUID(const uint8_t* bytes);
+  void InitializeFromBytes(const uint8_t* bytes);
 
   //! \brief Formats the %UUID per RFC 4122 §3.
   //!
   //! \return A string of the form `"00112233-4455-6677-8899-aabbccddeeff"`.
   std::string ToString() const;
 
-  uint8_t data[16];
+  // These fields are laid out according to RFC 4122 §4.1.2.
+  uint32_t data_1;
+  uint16_t data_2;
+  uint16_t data_3;
+  uint8_t data_4[2];
+  uint8_t data_5[6];
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MISC_UUID_H_