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quuid.cpp

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#include "quuid.h"

#include "qdatastream.h"

/*!
    \class QUuid
    \brief The QUuid class stores a Universally Unique Identifier (UUID).

    \reentrant
    \ingroup misc

    For objects or declarations that must be uniquely identified,
    UUIDs (also known as GUIDs) are widely used in order to assign a
    fixed and easy to compare value to the object or declaration. The
    128-bit value of a UUID is generated by an algorithm that
    guarantees that the value is unique.

    In Qt, UUIDs are wrapped by the QUuid struct which provides
    convenience functions for handling UUIDs. Most platforms provide
    a tool to generate new UUIDs, for example, \c uuidgen and \c
    guidgen.

    UUIDs generated by QUuid, are based on the \c Random version of the
    \c DCE (Distributed Computing Environment) standard.

    UUIDs can be constructed from numeric values or from strings, or
    using the static createUuid() function. They can be converted to a
    string with toString(). UUIDs have a variant() and a version(),
    and null UUIDs return true from isNull().
*/

/*!
    \fn QUuid::QUuid(const GUID &guid)

    Casts a Windows \a guid to a Qt QUuid.

    \warning This function is only for Windows platforms.
*/

/*!
    \fn QUuid &QUuid::operator=(const GUID &guid)

    Assigns a Windows \a guid to a Qt QUuid.

    \warning This function is only for Windows platforms.
*/

/*!
    \fn QUuid::operator GUID() const

    Returns a Windows GUID from a QUuid.

    \warning This function is only for Windows platforms.
*/

/*!
    \fn QUuid::QUuid()

    Creates the null UUID {00000000-0000-0000-0000-000000000000}.
*/

/*!
    \fn QUuid::QUuid(uint l, ushort w1, ushort w2, uchar b1, uchar b2, uchar b3, uchar b4, uchar b5, uchar b6, uchar b7, uchar b8)

    Creates a UUID with the value specified by the parameters, \a l,
    \a w1, \a w2, \a b1, \a b2, \a b3, \a b4, \a b5, \a b6, \a b7, \a
    b8.

    Example:
    \code
    // {67C8770B-44F1-410A-AB9A-F9B5446F13EE}
    QUuid IID_MyInterface(0x67c8770b, 0x44f1, 0x410a, 0xab, 0x9a, 0xf9, 0xb5, 0x44, 0x6f, 0x13, 0xee)
    \endcode
*/

#ifndef QT_NO_QUUID_STRING
/*!
    Creates a QUuid object from the string \a text. The function can
    only convert a string in the format
    {HHHHHHHH-HHHH-HHHH-HHHH-HHHHHHHHHHHH} (where 'H' stands for a hex
    digit). If the conversion fails a null UUID is created.
*/
00126 QUuid::QUuid(const QString &text)
{
    bool ok;
    if (text.isEmpty()) {
        *this = QUuid();
        return;
    }
    QString temp = text.toUpper();
    if (temp[0] != QLatin1Char('{'))
        temp = QLatin1Char('{') + text;
    if (text[(int)text.length()-1] != QLatin1Char('}'))
        temp += QLatin1Char('}');

    data1 = temp.mid(1, 8).toULongLong(&ok, 16);
    if (!ok) {
        *this = QUuid();
        return;
    }

    data2 = temp.mid(10, 4).toUInt(&ok, 16);
    if (!ok) {
        *this = QUuid();
        return;
    }
    data3 = temp.mid(15, 4).toUInt(&ok, 16);
    if (!ok) {
        *this = QUuid();
        return;
    }
    data4[0] = temp.mid(20, 2).toUInt(&ok, 16);
    if (!ok) {
        *this = QUuid();
        return;
    }
    data4[1] = temp.mid(22, 2).toUInt(&ok, 16);
    if (!ok) {
        *this = QUuid();
        return;
    }
    for (int i = 2; i<8; i++) {
        data4[i] = temp.mid(25 + (i-2)*2, 2).toUShort(&ok, 16);
        if (!ok) {
            *this = QUuid();
            return;
        }
    }
}

/*!
    \internal
*/
00177 QUuid::QUuid(const char *text)
{
    *this = QUuid(QString::fromLatin1(text));
}
#endif

/*!
    \fn bool QUuid::operator==(const QUuid &other) const

    Returns true if this QUuid and the \a other QUuid are identical;
    otherwise returns false.
*/

/*!
    \fn bool QUuid::operator!=(const QUuid &other) const

    Returns true if this QUuid and the \a other QUuid are different;
    otherwise returns false.
*/
#ifndef QT_NO_QUUID_STRING
/*!
    \fn QUuid::operator QString() const

    Returns the string representation of the uuid.

    \sa toString()
*/

static QString uuidhex(uint data, int digits)
{
    return QString::number(data, 16).rightJustified(digits, QLatin1Char('0'));
}

/*!
    Returns the string representation of the uuid.
*/
00213 QString QUuid::toString() const
{
    QString result;

    QChar dash = QLatin1Char('-');
    result = QLatin1Char('{') + uuidhex(data1,8);
    result += dash;
    result += uuidhex(data2,4);
    result += dash;
    result += uuidhex(data3,4);
    result += dash;
    result += uuidhex(data4[0],2);
    result += uuidhex(data4[1],2);
    result += dash;
    for (int i = 2; i < 8; i++)
        result += uuidhex(data4[i],2);

    return result + QLatin1Char('}');
}
#endif

#ifndef QT_NO_DATASTREAM
/*!
    \relates QUuid
    Writes the uuid \a id to the datastream \a s.
*/
00239 QDataStream &operator<<(QDataStream &s, const QUuid &id)
{
    s << (quint32)id.data1;
    s << (quint16)id.data2;
    s << (quint16)id.data3;
    for (int i = 0; i < 8; i++)
        s << (quint8)id.data4[i];
    return s;
}

/*!
    \relates QUuid
    Reads uuid from from the stream \a s into \a id.
*/
00253 QDataStream &operator>>(QDataStream &s, QUuid &id)
{
    quint32 u32;
    quint16 u16;
    quint8 u8;
    s >> u32;
    id.data1 = u32;
    s >> u16;
    id.data2 = u16;
    s >> u16;
    id.data3 = u16;
    for (int i = 0; i < 8; i++) {
        s >> u8;
        id.data4[i] = u8;
    }
    return s;
}
#endif

/*!
    Returns true if this is the null UUID
    {00000000-0000-0000-0000-000000000000}; otherwise returns false.
*/
00276 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;
}

/*!
    \enum QUuid::Variant

    This enum defines the variant of the UUID, which is the scheme
    which defines the layout of the 128-bits value.

    \value VarUnknown Variant is unknown
    \value NCS Reserved for NCS (Network Computing System) backward compatibility
    \value DCE Distributed Computing Environment, the scheme used by QUuid
    \value Microsoft Reserved for Microsoft backward compatibility (GUID)
    \value Reserved Reserved for future definition
*/

/*!
    \enum QUuid::Version

    This enum defines the version of the UUID.

    \value VerUnknown Version is unknown
    \value Time Time-based, by using timestamp, clock sequence, and
    MAC network card address (if available) for the node sections
    \value EmbeddedPOSIX DCE Security version, with embedded POSIX UUIDs
    \value Name Name-based, by using values from a name for all sections
    \value Random Random-based, by using random numbers for all sections
*/

/*!
    \fn QUuid::Variant QUuid::variant() const

    Returns the variant of the UUID.
    The null UUID is considered to be of an unknown variant.

    \sa version()
*/
00317 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;
}

/*!
    \fn QUuid::Version QUuid::version() const

    Returns the version of the UUID, if the UUID is of the DCE
    variant; otherwise returns VerUnknown.

    \sa variant()
*/
00337 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;
}

/*!
    \fn bool QUuid::operator<(const QUuid &other) const

    Returns true if this QUuid is of the same variant,
    and lexicographically before the \a other QUuid;
    otherwise returns false.

    \sa variant()
*/
#define ISLESS(f1, f2) if (f1!=f2) return (f1<f2);
00359 bool QUuid::operator<(const QUuid &other) const
{
    if (variant() != other.variant())
        return false;

    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;
}

/*!
    \fn bool QUuid::operator>(const QUuid &other) const

    Returns true if this QUuid is of the same variant,
    and lexicographically after the \a other QUuid;
    otherwise returns false.

    \sa variant()
*/
#define ISMORE(f1, f2) if (f1!=f2) return (f1>f2);
00383 bool QUuid::operator>(const QUuid &other) const
{
    if (variant() != other.variant())
        return false;

    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;
}

/*!
    \fn QUuid QUuid::createUuid()

    Returns a new UUID of \c DCE variant, and \c Random type. The
    UUIDs generated are based on the platform specific pseudo-random
    generator, which is usually not a cryptographic-quality random
    number generator. Therefore, a UUID is not guaranteed to be unique
    cross application instances.

    On Windows, the new UUID is extremely likely to be unique on the
    same or any other system, networked or not.

    \sa variant(), version()
*/
#if defined(Q_OS_WIN32)
#include <objbase.h> // For CoCreateGuid
QUuid QUuid::createUuid()
{
    GUID guid;
    CoCreateGuid(&guid);
    QUuid result = guid;
    return result;
}
#else // !Q_OS_WIN32
#include "qdatetime.h"
#include "stdlib.h" // For srand/rand
00423 QUuid QUuid::createUuid()
{
    static const int intbits = sizeof(int)*8;
    static int randbits = 0;
    if (!randbits) {
        int max = RAND_MAX;
        do { ++randbits; } while ((max=max>>1));
        qsrand((uint)QDateTime::currentDateTime().toTime_t());
        qrand(); // Skip first
    }

    QUuid result;
    uint *data = &(result.data1);
    int chunks = 16 / sizeof(uint);
    while (chunks--) {
        uint randNumber = 0;
        for (int filled = 0; filled < intbits; filled += randbits)
            randNumber |= qrand()<<filled;
         *(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

/*!
    \fn bool QUuid::operator==(const GUID &guid) const

    Returns true if this UUID is equal to the Windows GUID \a guid;
    otherwise returns false.
*/

/*!
    \fn bool QUuid::operator!=(const GUID &guid) const

    Returns true if this UUID is not equal to the Windows GUID \a
    guid; otherwise returns false.
*/

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