1/*
2* Copyright (C) 2010 Google Inc. All rights reserved.
3*
4* Redistribution and use in source and binary forms, with or without
5* modification, are permitted provided that the following conditions are
6* met:
7*
8*     * Redistributions of source code must retain the above copyright
9* notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "platform/UUID.h"
33
34#include "wtf/CryptographicallyRandomNumber.h"
35#include "wtf/HexNumber.h"
36#include "wtf/text/StringBuilder.h"
37
38namespace blink {
39
40String createCanonicalUUIDString()
41{
42    unsigned randomData[4];
43    cryptographicallyRandomValues(reinterpret_cast<unsigned char*>(randomData), sizeof(randomData));
44
45    // Format as Version 4 UUID.
46    StringBuilder builder;
47    builder.reserveCapacity(36);
48    appendUnsignedAsHexFixedSize(randomData[0], builder, 8, Lowercase);
49    builder.append('-');
50    appendUnsignedAsHexFixedSize(randomData[1] >> 16, builder, 4, Lowercase);
51    builder.appendLiteral("-4");
52    appendUnsignedAsHexFixedSize(randomData[1] & 0x00000fff, builder, 3, Lowercase);
53    builder.append('-');
54    appendUnsignedAsHexFixedSize((randomData[2] >> 30) | 0x8, builder, 1, Lowercase);
55    appendUnsignedAsHexFixedSize((randomData[2] >> 16) & 0x00000fff, builder, 3, Lowercase);
56    builder.append('-');
57    appendUnsignedAsHexFixedSize(randomData[2] & 0x0000ffff, builder, 4, Lowercase);
58    appendUnsignedAsHexFixedSize(randomData[3], builder, 8, Lowercase);
59    return builder.toString();
60}
61
62}
63