105 lines
3.5 KiB
C++
105 lines
3.5 KiB
C++
// Copyright (c) 2006, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "common/linux/guid_creator.h"
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#include <assert.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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//
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// GUIDGenerator
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//
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// This class is used to generate random GUID.
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// Currently use random number to generate a GUID since Linux has
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// no native GUID generator. This should be OK since we don't expect
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// crash to happen very offen.
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//
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class GUIDGenerator {
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public:
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static uint32_t BytesToUInt32(const uint8_t bytes[]) {
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return ((uint32_t) bytes[0]
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| ((uint32_t) bytes[1] << 8)
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| ((uint32_t) bytes[2] << 16)
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| ((uint32_t) bytes[3] << 24));
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}
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static void UInt32ToBytes(uint8_t bytes[], uint32_t n) {
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bytes[0] = n & 0xff;
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bytes[1] = (n >> 8) & 0xff;
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bytes[2] = (n >> 16) & 0xff;
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bytes[3] = (n >> 24) & 0xff;
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}
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static bool CreateGUID(GUID *guid) {
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InitOnce();
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guid->data1 = random();
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guid->data2 = (uint16_t)(random());
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guid->data3 = (uint16_t)(random());
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UInt32ToBytes(&guid->data4[0], random());
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UInt32ToBytes(&guid->data4[4], random());
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return true;
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}
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private:
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static void InitOnce() {
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pthread_once(&once_control, &InitOnceImpl);
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}
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static void InitOnceImpl() {
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srandom(time(NULL));
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}
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static pthread_once_t once_control;
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};
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pthread_once_t GUIDGenerator::once_control = PTHREAD_ONCE_INIT;
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bool CreateGUID(GUID *guid) {
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return GUIDGenerator::CreateGUID(guid);
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}
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// Parse guid to string.
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bool GUIDToString(const GUID *guid, char *buf, int buf_len) {
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// Should allow more space the the max length of GUID.
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assert(buf_len > kGUIDStringLength);
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int num = snprintf(buf, buf_len, kGUIDFormatString,
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guid->data1, guid->data2, guid->data3,
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GUIDGenerator::BytesToUInt32(&(guid->data4[0])),
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GUIDGenerator::BytesToUInt32(&(guid->data4[4])));
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if (num != kGUIDStringLength)
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return false;
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buf[num] = '\0';
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return true;
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}
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