quuid.cpp

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#include "quuid.h"

#include "qdatastream.h"
#include "qendian.h"

QT_BEGIN_NAMESPACE

#ifndef QT_NO_QUUID_STRING
template <class Char, class Integral>
void _q_toHex(Char *&dst, Integral value)
{
    static const char digits[] = "0123456789abcdef";

    value = qToBigEndian(value);

    const char* p = reinterpret_cast<const char*>(&value);

    for (uint i = 0; i < sizeof(Integral); ++i, dst += 2) {
        uint j = (p[i] >> 4) & 0xf;
        dst[0] = Char(digits[j]);
        j = p[i] & 0xf;
        dst[1] = Char(digits[j]);
    }
}

template <class Char, class Integral>
bool _q_fromHex(const Char *&src, Integral &value)
{
    value = 0;

    for (uint i = 0; i < sizeof(Integral) * 2; ++i) {
        int ch = *src++;
        int tmp;
        if (ch >= '0' && ch <= '9')
            tmp = ch - '0';
        else if (ch >= 'a' && ch <= 'f')
            tmp = ch - 'a' + 10;
        else if (ch >= 'A' && ch <= 'F')
            tmp = ch - 'A' + 10;
        else
            return false;

        value = value * 16 + tmp;
    }

    return true;
}

template <class Char>
void _q_uuidToHex(Char *&dst, const uint &d1, const ushort &d2, const ushort &d3, const uchar (&d4)[8])
{
    *dst++ = Char('{');
    _q_toHex(dst, d1);
    *dst++ = Char('-');
    _q_toHex(dst, d2);
    *dst++ = Char('-');
    _q_toHex(dst, d3);
    *dst++ = Char('-');
    for (int i = 0; i < 2; i++)
        _q_toHex(dst, d4[i]);
    *dst++ = Char('-');
    for (int i = 2; i < 8; i++)
        _q_toHex(dst, d4[i]);
    *dst = Char('}');
}

template <class Char>
bool _q_uuidFromHex(const Char *&src, uint &d1, ushort &d2, ushort &d3, uchar (&d4)[8])
{
    if (*src == Char('{'))
        src++;
    if (!_q_fromHex(src, d1)
            || *src++ != Char('-')
            || !_q_fromHex(src, d2)
            || *src++ != Char('-')
            || !_q_fromHex(src, d3)
            || *src++ != Char('-')
            || !_q_fromHex(src, d4[0])
            || !_q_fromHex(src, d4[1])
            || *src++ != Char('-')
            || !_q_fromHex(src, d4[2])
            || !_q_fromHex(src, d4[3])
            || !_q_fromHex(src, d4[4])
            || !_q_fromHex(src, d4[5])
            || !_q_fromHex(src, d4[6])
            || !_q_fromHex(src, d4[7])) {
        return false;
    }

    return true;
}
#endif

#ifndef QT_NO_QUUID_STRING

QUuid::QUuid(const QString &text)
{
    if (text.length() < 36) {
        *this = QUuid();
        return;
    }

    const ushort *data = reinterpret_cast<const ushort *>(text.unicode());

    if (*data == '{' && text.length() < 37) {
        *this = QUuid();
        return;
    }

    if (!_q_uuidFromHex(data, data1, data2, data3, data4)) {
        *this = QUuid();
        return;
    }
}

QUuid::QUuid(const char *text)
{
    if (!text) {
        *this = QUuid();
        return;
    }

    if (!_q_uuidFromHex(text, data1, data2, data3, data4)) {
        *this = QUuid();
        return;
    }
}

QUuid::QUuid(const QByteArray &text)
{
    if (text.length() < 36) {
        *this = QUuid();
        return;
    }

    const char *data = text.constData();

    if (*data == '{' && text.length() < 37) {
        *this = QUuid();
        return;
    }

    if (!_q_uuidFromHex(data, data1, data2, data3, data4)) {
        *this = QUuid();
        return;
    }
}
#endif

QUuid QUuid::fromRfc4122(const QByteArray &bytes)
{
    if (bytes.isEmpty() || bytes.length() != 16)
        return QUuid();

    uint d1;
    ushort d2, d3;
    uchar d4[8];

    const uchar *data = reinterpret_cast<const uchar *>(bytes.constData());

    d1 = qFromBigEndian<quint32>(data);
    data += sizeof(quint32);
    d2 = qFromBigEndian<quint16>(data);
    data += sizeof(quint16);
    d3 = qFromBigEndian<quint16>(data);
    data += sizeof(quint16);

    for (int i = 0; i < 8; ++i) {
        d4[i] = *(data);
        data++;
    }

    return QUuid(d1, d2, d3, d4[0], d4[1], d4[2], d4[3], d4[4], d4[5], d4[6], d4[7]);
}

#ifndef QT_NO_QUUID_STRING

QString QUuid::toString() const
{
    QString result(38, Qt::Uninitialized);
    ushort *data = (ushort *)result.unicode();

    _q_uuidToHex(data, data1, data2, data3, data4);

    return result;
}

QByteArray QUuid::toByteArray() const
{
    QByteArray result(38, Qt::Uninitialized);
    char *data = result.data();

    _q_uuidToHex(data, data1, data2, data3, data4);

    return result;
}
#endif

QByteArray QUuid::toRfc4122() const
{
    // we know how many bytes a UUID has, I hope :)
    QByteArray bytes(16, Qt::Uninitialized);
    uchar *data = reinterpret_cast<uchar*>(bytes.data());

    qToBigEndian(data1, data);
    data += sizeof(quint32);
    qToBigEndian(data2, data);
    data += sizeof(quint16);
    qToBigEndian(data3, data);
    data += sizeof(quint16);

    for (int i = 0; i < 8; ++i) {
        *(data) = data4[i];
        data++;
    }

    return bytes;
}

#ifndef QT_NO_DATASTREAM

QDataStream &operator<<(QDataStream &s, const QUuid &id)
{
    QByteArray bytes;
    if (s.byteOrder() == QDataStream::BigEndian) {
        bytes = id.toRfc4122();
    } else {
        // we know how many bytes a UUID has, I hope :)
        bytes = QByteArray(16, Qt::Uninitialized);
        uchar *data = reinterpret_cast<uchar*>(bytes.data());

        qToLittleEndian(id.data1, data);
        data += sizeof(quint32);
        qToLittleEndian(id.data2, data);
        data += sizeof(quint16);
        qToLittleEndian(id.data3, data);
        data += sizeof(quint16);

        for (int i = 0; i < 8; ++i) {
            *(data) = id.data4[i];
            data++;
        }
    }

    if (s.writeRawData(bytes.data(), 16) != 16) {
        s.setStatus(QDataStream::WriteFailed);
    }
    return s;
}

QDataStream &operator>>(QDataStream &s, QUuid &id)
{
    QByteArray bytes(16, Qt::Uninitialized);
    if (s.readRawData(bytes.data(), 16) != 16) {
        s.setStatus(QDataStream::ReadPastEnd);
        return s;
    }

    if (s.byteOrder() == QDataStream::BigEndian) {
        id = QUuid::fromRfc4122(bytes);
    } else {
        const uchar *data = reinterpret_cast<const uchar *>(bytes.constData());

        id.data1 = qFromLittleEndian<quint32>(data);
        data += sizeof(quint32);
        id.data2 = qFromLittleEndian<quint16>(data);
        data += sizeof(quint16);
        id.data3 = qFromLittleEndian<quint16>(data);
        data += sizeof(quint16);

        for (int i = 0; i < 8; ++i) {
            id.data4[i] = *(data);
            data++;
        }
    }

    return s;
}
#endif // QT_NO_DATASTREAM

bool QUuid::isNull() const
{
    return data4[0] == 0 && data4[1] == 0 && data4[2] == 0 && data4[3] == 0 &&
           data4[4] == 0 && data4[5] == 0 && data4[6] == 0 && data4[7] == 0 &&
           data1 == 0 && data2 == 0 && data3 == 0;
}

QUuid::Variant QUuid::variant() const
{
    if (isNull())
        return VarUnknown;
    // Check the 3 MSB of data4[0]
    if ((data4[0] & 0x80) == 0x00) return NCS;
    else if ((data4[0] & 0xC0) == 0x80) return DCE;
    else if ((data4[0] & 0xE0) == 0xC0) return Microsoft;
    else if ((data4[0] & 0xE0) == 0xE0) return Reserved;
    return VarUnknown;
}

QUuid::Version QUuid::version() const
{
    // Check the 4 MSB of data3
    Version ver = (Version)(data3>>12);
    if (isNull()
         || (variant() != DCE)
         || ver < Time
         || ver > Random)
        return VerUnknown;
    return ver;
}

#define ISLESS(f1, f2) if (f1!=f2) return (f1<f2);
bool QUuid::operator<(const QUuid &other) const
{
    if (variant() != other.variant())
        return variant() < other.variant();

    ISLESS(data1, other.data1);
    ISLESS(data2, other.data2);
    ISLESS(data3, other.data3);
    for (int n = 0; n < 8; n++) {
        ISLESS(data4[n], other.data4[n]);
    }
    return false;
}

#define ISMORE(f1, f2) if (f1!=f2) return (f1>f2);
bool QUuid::operator>(const QUuid &other) const
{
    if (variant() != other.variant())
        return variant() > other.variant();

    ISMORE(data1, other.data1);
    ISMORE(data2, other.data2);
    ISMORE(data3, other.data3);
    for (int n = 0; n < 8; n++) {
        ISMORE(data4[n], other.data4[n]);
    }
    return false;
}

#if defined(Q_OS_WIN32) && ! defined(Q_CC_MWERKS)

QT_BEGIN_INCLUDE_NAMESPACE
#include <objbase.h> // For CoCreateGuid
QT_END_INCLUDE_NAMESPACE

QUuid QUuid::createUuid()
{
    GUID guid;
    CoCreateGuid(&guid);
    QUuid result = guid;
    return result;
}

#else // !Q_OS_WIN32

QT_BEGIN_INCLUDE_NAMESPACE
#include "qdatetime.h"
#include "qfile.h"
#include "qthreadstorage.h"
#include <stdlib.h> // for RAND_MAX
QT_END_INCLUDE_NAMESPACE

#if !defined(QT_BOOTSTRAPPED) && defined(Q_OS_UNIX)
Q_GLOBAL_STATIC(QThreadStorage<QFile *>, devUrandomStorage);
#endif

QUuid QUuid::createUuid()
{
    QUuid result;
    uint *data = &(result.data1);

#if defined(Q_OS_UNIX)
    QFile *devUrandom;
#  if !defined(QT_BOOTSTRAPPED)
    devUrandom = devUrandomStorage()->localData();
    if (!devUrandom) {
        devUrandom = new QFile(QLatin1String("/dev/urandom"));
        devUrandom->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
        devUrandomStorage()->setLocalData(devUrandom);
    }
# else
    QFile file(QLatin1String("/dev/urandom"));
    devUrandom = &file;
    devUrandom->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
# endif
    enum { AmountToRead = 4 * sizeof(uint) };
    if (devUrandom->isOpen()
        && devUrandom->read((char *) data, AmountToRead) == AmountToRead) {
        // we got what we wanted, nothing more to do
        ;
    } else
#endif
    {
        static const int intbits = sizeof(int)*8;
        static int randbits = 0;
        if (!randbits) {
            int r = 0;
            int max = RAND_MAX;
            do { ++r; } while ((max=max>>1));
            randbits = r;
        }

        // Seed the PRNG once per thread with a combination of current time, a
        // stack address and a serial counter (since thread stack addresses are
        // re-used).
#ifndef QT_BOOTSTRAPPED
        static QThreadStorage<int *> uuidseed;
        if (!uuidseed.hasLocalData())
        {
            int *pseed = new int;
            static QBasicAtomicInt serial = Q_BASIC_ATOMIC_INITIALIZER(2);
            qsrand(*pseed = QDateTime::currentDateTime().toTime_t()
                   + quintptr(&pseed)
                   + serial.fetchAndAddRelaxed(1));
            uuidseed.setLocalData(pseed);
        }
#else
        static bool seeded = false;
        if (!seeded)
            qsrand(QDateTime::currentDateTime().toTime_t()
                   + quintptr(&seeded));
#endif

        int chunks = 16 / sizeof(uint);
        while (chunks--) {
            uint randNumber = 0;
            for (int filled = 0; filled < intbits; filled += randbits)
                randNumber |= qrand()<<filled;
#if defined(Q_OS_SYMBIAN)
            // Symbian does not have /dev/urandom, so entropy is low.
            // Add more entropy from the kernel tick count (1ms resolution).
            // big multipler used to splatter the tick count bits over the whole 32 bits
            randNumber ^= User::NTickCount() * 0x3b9aca07;
#endif
            *(data+chunks) = randNumber;
        }
    }

    result.data4[0] = (result.data4[0] & 0x3F) | 0x80;        // UV_DCE
    result.data3 = (result.data3 & 0x0FFF) | 0x4000;        // UV_Random

    return result;
}
#endif // !Q_OS_WIN32

QT_END_NAMESPACE