third_party/WebKit/Source/platform/UUID.cpp

   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
  38 namespace blink {
  39
  40 String 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 static bool isLowercaseHex(char c)
  63 {
  64     return (('0' <= c && c <= '9') || ('a' <= c && c <= 'f'));
  65 }
  66
  67 bool isValidUUID(const String& uuid)
  68 {
  69     // 32 digits + 4 hyphens = 36 characters.
  70     if (uuid.length() != 36)
  71         return false;
  72
  73     for (size_t i = 0; i < uuid.length(); i++) {
  74         if (i == 8 || i == 13 || i == 18 || i == 23) {
  75             if (uuid[i] != '-')
  76                 return false;
  77         } else {
  78             if (!isLowercaseHex(uuid[i]))
  79                 return false;
  80         }
  81     }
  82
  83     return true;
  84 }
  85
  86 }