| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/guid.h" |
| |
| #include <stdint.h> |
| |
| #include "base/rand_util.h" |
| #include "base/strings/stringprintf.h" |
| |
| namespace base { |
| |
| std::string GenerateGUID() { |
| uint64_t sixteen_bytes[2] = {base::RandUint64(), base::RandUint64()}; |
| |
| // Set the GUID to version 4 as described in RFC 4122, section 4.4. |
| // The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, |
| // where y is one of [8, 9, A, B]. |
| |
| // Clear the version bits and set the version to 4: |
| sixteen_bytes[0] &= 0xffffffffffff0fffULL; |
| sixteen_bytes[0] |= 0x0000000000004000ULL; |
| |
| // Set the two most significant bits (bits 6 and 7) of the |
| // clock_seq_hi_and_reserved to zero and one, respectively: |
| sixteen_bytes[1] &= 0x3fffffffffffffffULL; |
| sixteen_bytes[1] |= 0x8000000000000000ULL; |
| |
| return RandomDataToGUIDString(sixteen_bytes); |
| } |
| |
| // TODO(cmasone): Once we're comfortable this works, migrate Windows code to |
| // use this as well. |
| std::string RandomDataToGUIDString(const uint64_t bytes[2]) { |
| return StringPrintf("%08X-%04X-%04X-%04X-%012llX", |
| static_cast<unsigned int>(bytes[0] >> 32), |
| static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff), |
| static_cast<unsigned int>(bytes[0] & 0x0000ffff), |
| static_cast<unsigned int>(bytes[1] >> 48), |
| bytes[1] & 0x0000ffffffffffffULL); |
| } |
| |
| } // namespace base |