91 lines
2.7 KiB
C++
91 lines
2.7 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/guid.h"
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#include <stddef.h>
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#include <stdint.h>
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#include "base/rand_util.h"
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#include "base/strings/string_util.h"
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#include "base/strings/stringprintf.h"
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namespace base {
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namespace {
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template <typename Char>
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bool IsLowerHexDigit(Char c) {
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return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f');
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}
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template <typename StringPieceType>
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bool IsValidGUIDInternal(StringPieceType guid, bool strict) {
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using CharType = typename StringPieceType::value_type;
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const size_t kGUIDLength = 36U;
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if (guid.length() != kGUIDLength)
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return false;
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for (size_t i = 0; i < guid.length(); ++i) {
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CharType current = guid[i];
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if (i == 8 || i == 13 || i == 18 || i == 23) {
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if (current != '-')
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return false;
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} else {
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if (strict ? !IsLowerHexDigit(current) : !IsHexDigit(current))
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return false;
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}
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}
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return true;
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}
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} // namespace
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std::string GenerateGUID() {
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uint64_t sixteen_bytes[2];
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// Use base::RandBytes instead of crypto::RandBytes, because crypto calls the
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// base version directly, and to prevent the dependency from base/ to crypto/.
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base::RandBytes(&sixteen_bytes, sizeof(sixteen_bytes));
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// Set the GUID to version 4 as described in RFC 4122, section 4.4.
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// The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx,
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// where y is one of [8, 9, A, B].
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// Clear the version bits and set the version to 4:
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sixteen_bytes[0] &= 0xffffffff'ffff0fffULL;
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sixteen_bytes[0] |= 0x00000000'00004000ULL;
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// Set the two most significant bits (bits 6 and 7) of the
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// clock_seq_hi_and_reserved to zero and one, respectively:
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sixteen_bytes[1] &= 0x3fffffff'ffffffffULL;
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sixteen_bytes[1] |= 0x80000000'00000000ULL;
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return RandomDataToGUIDString(sixteen_bytes);
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}
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bool IsValidGUID(base::StringPiece guid) {
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return IsValidGUIDInternal(guid, false /* strict */);
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}
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bool IsValidGUID(base::StringPiece16 guid) {
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return IsValidGUIDInternal(guid, false /* strict */);
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}
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bool IsValidGUIDOutputString(base::StringPiece guid) {
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return IsValidGUIDInternal(guid, true /* strict */);
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}
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std::string RandomDataToGUIDString(const uint64_t bytes[2]) {
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return StringPrintf("%08x-%04x-%04x-%04x-%012llx",
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static_cast<unsigned int>(bytes[0] >> 32),
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static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff),
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static_cast<unsigned int>(bytes[0] & 0x0000ffff),
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static_cast<unsigned int>(bytes[1] >> 48),
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bytes[1] & 0x0000ffff'ffffffffULL);
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}
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} // namespace base
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