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// 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 <stddef.h>
#include <stdint.h>
#include "base/rand_util.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
namespace base {
namespace {
bool IsLowerHexDigit(char c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f');
}
bool IsValidGUIDInternal(const base::StringPiece& guid, bool strict) {
const size_t kGUIDLength = 36U;
if (guid.length() != kGUIDLength)
return false;
for (size_t i = 0; i < guid.length(); ++i) {
char current = guid[i];
if (i == 8 || i == 13 || i == 18 || i == 23) {
if (current != '-')
return false;
} else {
if ((strict && !IsLowerHexDigit(current)) || !IsHexDigit(current))
return false;
}
}
return true;
}
} // namespace
std::string GenerateGUID() {
uint64_t sixteen_bytes[2];
// Use base::RandBytes instead of crypto::RandBytes, because crypto calls the
// base version directly, and to prevent the dependency from base/ to crypto/.
base::RandBytes(&sixteen_bytes, sizeof(sixteen_bytes));
// 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] &= 0xffffffff'ffff0fffULL;
sixteen_bytes[0] |= 0x00000000'00004000ULL;
// 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] &= 0x3fffffff'ffffffffULL;
sixteen_bytes[1] |= 0x80000000'00000000ULL;
return RandomDataToGUIDString(sixteen_bytes);
}
bool IsValidGUID(const base::StringPiece& guid) {
return IsValidGUIDInternal(guid, false /* strict */);
}
bool IsValidGUIDOutputString(const base::StringPiece& guid) {
return IsValidGUIDInternal(guid, true /* strict */);
}
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] & 0x0000ffff'ffffffffULL);
}
} // namespace base