path: root/src/corelib/plugin/quuid_p.h

// Copyright (C) 2020 The Qt Company Ltd.// Copyright (C) 2021 Intel Corporation.// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only#ifndef QUUID_P_H#define QUUID_P_H//// W A R N I N G// -------------//// This file is not part of the Qt API. It exists for the convenience// of the QLibrary class. This header file may change from// version to version without notice, or even be removed.//// We mean it.//#include"quuid.h"#include <QtCore/qrandom.h>#include <chrono> QT_BEGIN_NAMESPACE #ifndef QT_BOOTSTRAPPEDstaticinline QUuid createUuidV7_internal(std::chrono::time_point<std::chrono::system_clock,std::chrono::nanoseconds> tp){ QUuid result;using namespacestd::chrono;const nanoseconds nsecSinceEpoch = tp.time_since_epoch();constauto msecSinceEpoch = floor<milliseconds>(nsecSinceEpoch);const quint64 frac = (nsecSinceEpoch - msecSinceEpoch).count();// Lower 48 bits of the timestampconst quint64 msecs =quint64(msecSinceEpoch.count()) &0xffffffffffff; result.data1 =uint(msecs >>16); result.data2 =ushort(msecs);// rand_a: use a 12-bit sub-millisecond timestamp for additional monotonicity// https://datatracker.ietf.org/doc/html/rfc9562#monotonicity_counters (Method 3)// "frac" is a number between 0 and 999,999, so the lowest 20 bits// should be roughly random. Use the high 12 of those for additional// monotonicity. result.data3 = frac >>8; result.data3 &=0x0FFF; result.data3 |=ushort(7) <<12;// rand_b: 62 bits of random data (64 - 2 bits for the variant)const quint64 random =QRandomGenerator::system()->generate64();memcpy(result.data4, &random,sizeof(quint64)); result.data4[0] = (result.data4[0] &0x3F) |0x80;// UV_DCEreturn result;}#endif QT_END_NAMESPACE #endif// QUUID_P_H