marja@chromium.org | 9158ee0 | 2012-06-14 23:22:07 +0900 | [diff] [blame] | 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "base/guid.h" |
| 6 | |
| 7 | #include "base/rand_util.h" |
avi@chromium.org | 94bd573 | 2013-06-11 22:36:37 +0900 | [diff] [blame] | 8 | #include "base/strings/stringprintf.h" |
marja@chromium.org | 9158ee0 | 2012-06-14 23:22:07 +0900 | [diff] [blame] | 9 | |
| 10 | namespace base { |
| 11 | |
| 12 | std::string GenerateGUID() { |
| 13 | uint64 sixteen_bytes[2] = { base::RandUint64(), base::RandUint64() }; |
benchan | 89412aa | 2014-09-05 23:19:39 +0900 | [diff] [blame] | 14 | |
| 15 | // Set the GUID to version 4 as described in RFC 4122, section 4.4. |
| 16 | // The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, |
| 17 | // where y is one of [8, 9, A, B]. |
| 18 | |
| 19 | // Clear the version bits and set the version to 4: |
| 20 | sixteen_bytes[0] &= 0xffffffffffff0fffULL; |
| 21 | sixteen_bytes[0] |= 0x0000000000004000ULL; |
| 22 | |
| 23 | // Set the two most significant bits (bits 6 and 7) of the |
| 24 | // clock_seq_hi_and_reserved to zero and one, respectively: |
| 25 | sixteen_bytes[1] &= 0x3fffffffffffffffULL; |
| 26 | sixteen_bytes[1] |= 0x8000000000000000ULL; |
| 27 | |
marja@chromium.org | 9158ee0 | 2012-06-14 23:22:07 +0900 | [diff] [blame] | 28 | return RandomDataToGUIDString(sixteen_bytes); |
| 29 | } |
| 30 | |
| 31 | // TODO(cmasone): Once we're comfortable this works, migrate Windows code to |
| 32 | // use this as well. |
| 33 | std::string RandomDataToGUIDString(const uint64 bytes[2]) { |
| 34 | return StringPrintf("%08X-%04X-%04X-%04X-%012llX", |
| 35 | static_cast<unsigned int>(bytes[0] >> 32), |
| 36 | static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff), |
| 37 | static_cast<unsigned int>(bytes[0] & 0x0000ffff), |
| 38 | static_cast<unsigned int>(bytes[1] >> 48), |
| 39 | bytes[1] & 0x0000ffffffffffffULL); |
| 40 | } |
| 41 | |
danakj | 651c3e2 | 2015-03-07 10:51:42 +0900 | [diff] [blame^] | 42 | } // namespace base |