qdatetime.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

    false.
*/

/*!
    \fn bool QDate::operator<=(const QDate &d) const

    Returns true if this date is earlier than or equal to \a d;
    otherwise returns false.
*/

/*!
    \fn bool QDate::operator>(const QDate &d) const

    Returns true if this date is later than \a d; otherwise returns
    false.
*/

/*!
    \fn bool QDate::operator>=(const QDate &d) const

    Returns true if this date is later than or equal to \a d;
    otherwise returns false.
*/

/*!
    \overload
    Returns the current date, as reported by the system clock.

    \sa QTime::currentTime(), QDateTime::currentDateTime()
*/

QDate QDate::currentDate()
{
    QDate d;
#if defined(Q_OS_WIN32)
    SYSTEMTIME st;
    memset(&st, 0, sizeof(SYSTEMTIME));
    GetLocalTime(&st);
    d.jd = QDate::gregorianToJulian(st.wYear, st.wMonth, st.wDay);
#else
    // posix compliant system
    time_t ltime;
    time(&ltime);
    tm *t;

#if !defined(QT_NO_THREAD) && defined(_POSIX_THREAD_SAFE_FUNCTIONS)
    // use the reentrant version of localtime() where available
    tm res;
    t = localtime_r(&ltime, &res);
#else
    t = localtime(&ltime);
#endif // !QT_NO_THREAD && _POSIX_THREAD_SAFE_FUNCTIONS

    d.jd = gregorianToJulian(t->tm_year + 1900, t->tm_mon + 1, t->tm_mday);
#endif
    return d;
}

#ifndef QT_NO_DATESTRING
/*!
    \fn QDate QDate::fromString(const QString &string, Qt::DateFormat format)

    Returns the QDate represented by the \a string, using the
    \a format given, or an invalid date if the string cannot be
    parsed.

    Note for Qt::TextDate: It is recommended that you use the
    English short month names (e.g. "Jan"). Although localized month
    names can also be used, they depend on the user's locale settings.

    \warning Qt::LocalDate cannot be used here.
*/
QDate QDate::fromString(const QString& s, Qt::DateFormat f)
{
    if ((s.isEmpty()) || (f == Qt::LocalDate)) {
        QDate d;
        d.jd = 0;
        return d;
    }
    switch (f) {
    case Qt::ISODate:
        {
            int year(s.mid(0, 4).toInt());
            int month(s.mid(5, 2).toInt());
            int day(s.mid(8, 2).toInt());
            if (year && month && day)
                return QDate(year, month, day);
        }
        break;
    default:
#ifndef QT_NO_TEXTDATE
    case Qt::TextDate:
        {
            /*
              This will fail gracefully if the input string doesn't
              contain any space.
            */
            int monthPos = s.indexOf(QLatin1Char(' ')) + 1;
            int dayPos = s.indexOf(QLatin1Char(' '), monthPos) + 1;

            QString monthName(s.mid(monthPos, dayPos - monthPos - 1));
            int month = -1;

            // try English names first
            for (int i = 0; i < 12; i++) {
                if (monthName == QLatin1String(qt_shortMonthNames[i])) {
                    month = i + 1;
                    break;
                }
            }

            // try the localized names
            if (month == -1) {
                for (int i = 0; i < 12; i++) {
                    if (monthName == shortMonthName(i + 1)) {
                        month = i + 1;
                        break;
                    }
                }
            }
            if (month < 1 || month > 12) {
                QDate d;
                d.jd = 0;
                return d;
            }
            int day = s.mid(dayPos, 2).trimmed().toInt();
            int year = s.right(4).toInt();
            return QDate(year, month, day);
        }
#else
        break;
#endif
    }
    return QDate();
}

/*!
    \fn QDate::fromString(const QString &string, const QString &format)

    Returns the QDate represented by the \a string, using the \a
    format given, or an invalid date if the string cannot be parsed.

    These expressions may be used for the format:

    \table
    \header \i Expression \i Output
    \row \i d \i The day as a number without a leading zero (1 to 31)
    \row \i dd \i The day as a number with a leading zero (01 to 31)
    \row \i ddd
         \i The abbreviated localized day name (e.g. 'Mon' to 'Sun').
            Uses QDate::shortDayName().
    \row \i dddd
         \i The long localized day name (e.g. 'Monday' to 'Sunday').
            Uses QDate::longDayName().
    \row \i M \i The month as a number without a leading zero (1 to 12)
    \row \i MM \i The month as a number with a leading zero (01 to 12)
    \row \i MMM
         \i The abbreviated localized month name (e.g. 'Jan' to 'Dec').
            Uses QDate::shortMonthName().
    \row \i MMMM
         \i The long localized month name (e.g. 'January' to 'December').
            Uses QDate::longMonthName().
    \row \i yy \i The year as two digit number (00 to 99)
    \row \i yyyy \i The year as four digit number (1752 to 8000)
    \endtable

    All other input characters will be treated as text. Any sequence
    of characters that are enclosed in single quotes will also be
    treated as text and will not be used as an expression. For example:

    \code
        QDate date = QDate::fromString("1MM12car2003", "d'MM'MMcaryyyy");
        // date is 1 December 2003
    \endcode

    If the format is not satisfied, an invalid QDate is returned. The
    expressions that don't expect leading zeroes (d, M) will be
    greedy. This means that they will use two digits even if this
    will put them outside the accepted range of values and leaves too
    few digits for other sections. For example, the following format
    string could have meant January 30 but the M will grab two
    digits, resulting in an invalid date:

    \code
        QDate date = QDate::fromString("130", "Md"); // invalid
    \endcode

    For any field that is not represented in the format the following
    defaults are used:

    \table
    \header \i Field  \i Default value
    \row    \i Year   \i 1900
    \row    \i Month  \i 1
    \row    \i Day    \i 1
    \endtable

    The following examples demonstrate the default values:

    \code
        QDate::fromString("1.30", "M.d");           // January 30 1900
        QDate::fromString("20000110", "yyyyMMdd");  // January 10, 2000
        QDate::fromString("20000110", "yyyyMd");    // January 10, 2000
    \endcode

    \sa QDateTime::fromString(), QTime::fromString(), QDate::toString(),
        QDateTime::toString(), QTime::toString()
*/

QDate QDate::fromString(const QString &string, const QString &format)
{
    QDate date;
#ifndef QT_BOOTSTRAPPED
    QDateTimeParser dt(QVariant::Date);
    if (dt.parseFormat(format))
        dt.fromString(string, &date, 0);
#else
    Q_UNUSED(string);
    Q_UNUSED(format);
#endif
    return date;
}
#endif // QT_NO_DATESTRING

/*!
    \overload

    Returns true if the specified date (year \a y, month \a m, and day
    \a d) is valid; otherwise returns false.

    Example:
    \code
        QDate::isValid(2002, 5, 17);  // true
        QDate::isValid(2002, 2, 30);  // false (Feb 30 does not exist)
        QDate::isValid(2004, 2, 29);  // true (2004 is a leap year)
        QDate::isValid(1202, 6, 6);   // false (1202 is pre-Gregorian)
    \endcode

    \warning A \a y value in the range 00 to 99 is interpreted as
    1900 to 1999.

    \sa isNull(), setYMD()
*/

bool QDate::isValid(int y, int m, int d)
{
    if (y >= 0 && y <= 99)
        y += 1900;
    else if (y < FIRST_YEAR || (y == FIRST_YEAR && (m < 9 || (m == 9 && d < 14))))
        return false;
    return (d > 0 && m > 0 && m <= 12) &&
           (d <= monthDays[m] || (d == 29 && m == 2 && isLeapYear(y)));
}

/*!
    \fn bool QDate::isLeapYear(int year)

    Returns true if the specified \a year is a leap year; otherwise
    returns false.
*/

bool QDate::isLeapYear(int y)
{
    return y % 4 == 0 && y % 100 != 0 || y % 400 == 0;
}

/*!
  \internal
  Converts a Gregorian date to a Julian day.
  This algorithm is taken from Communications of the ACM, Vol 6, No 8.
  \sa julianToGregorian()
*/

uint QDate::gregorianToJulian(int y, int m, int d)
{
    uint c, ya;
    if (y <= 99)
        y += 1900;
    if (m > 2) {
        m -= 3;
    } else {
        m += 9;
        y--;
    }
    c = y;                                        // NOTE: Sym C++ 6.0 bug
    c /= 100;
    ya = y - 100*c;
    return 1721119 + d + (146097*c)/4 + (1461*ya)/4 + (153*m+2)/5;
}

/*!
  \internal
  Converts a Julian day to a Gregorian date.
  This algorithm is taken from Communications of the ACM, Vol 6, No 8.
  \sa gregorianToJulian()
*/

void QDate::julianToGregorian(uint jd, int &y, int &m, int &d)
{
    uint x;
    uint j = jd - 1721119;
    y = (j*4 - 1)/146097;
    j = j*4 - 146097*y - 1;
    x = j/4;
    j = (x*4 + 3) / 1461;
    y = 100*y + j;
    x = (x*4) + 3 - 1461*j;
    x = (x + 4)/4;
    m = (5*x - 3)/153;
    x = 5*x - 3 - 153*m;
    d = (x + 5)/5;
    if (m < 10) {
        m += 3;
    } else {
        m -= 9;
        y++;
    }
}

/*! \fn static QDate QDate::fromJulianDay(int jd)

    Converts the Julian day \a jd to a QDate.

    \sa toJulianDay()
*/

/*! \fn int QDate::toJulianDay() const

    Converts the date to a Julian day.

    \sa fromJulianDay()
*/

/*****************************************************************************
  QTime member functions
 *****************************************************************************/

/*!
    \class QTime
    \reentrant

    \brief The QTime class provides clock time functions.

    \ingroup time
    \mainclass

    A QTime object contains a clock time, i.e. the number of hours,
    minutes, seconds, and milliseconds since midnight. It can read the
    current time from the system clock and measure a span of elapsed
    time. It provides functions for comparing times and for
    manipulating a time by adding a number of (milli)seconds.

    QTime uses the 24-hour clock format; it has no concept of AM/PM.
    It operates in local time; it knows nothing about time zones or
    daylight savings time.

    A QTime object is typically created either by giving the number of
    hours, minutes, seconds, and milliseconds explicitly, or by using
    the static function currentTime(), which creates a QTime object
    that contains the system's clock time. Note that the accuracy
    depends on the accuracy of the underlying operating system; not
    all systems provide 1-millisecond accuracy.

    The hour(), minute(), second(), and msec() functions provide
    access to the number of hours, minutes, seconds, and milliseconds
    of the time. The same information is provided in textual format by
    the toString() function.

    QTime provides a full set of operators to compare two QTime
    objects. One time is considered smaller than another if it is
    earlier than the other.

    The time a given number of seconds or milliseconds later than a
    given time can be found using the addSecs() or addMSecs()
    functions. Correspondingly, the number of (milli)seconds between
    two times can be found using the secsTo() or msecsTo() functions.

    QTime can be used to measure a span of elapsed time using the
    start(), restart(), and elapsed() functions.

    \sa QDate, QDateTime
*/

/*!
    \fn QTime::QTime()

    Constructs a null time object.

    \sa isValid()
*/

/*!
    Constructs a time with hour \a h, minute \a m, seconds \a s and
    milliseconds \a ms.

    \a h must be in the range 0 to 23, \a m and \a s must be in the
    range 0 to 59, and \a ms must be in the range 0 to 999.

    \sa isValid()
*/

QTime::QTime(int h, int m, int s, int ms)
{
    setHMS(h, m, s, ms);
}


/*!
    \fn bool QTime::isNull() const

    Returns true if the time is null; otherwise returns false. A null time
    is also an invalid time.

    \sa isValid()
*/

/*!
    Returns true if the time is valid; otherwise returns false. For example,
    the time 23:30:55.746 is valid, but 24:12:30 is invalid.

    \sa isNull()
*/

bool QTime::isValid() const
{
    return mds > NullTime && mds < MSECS_PER_DAY;
}


/*!
    Returns the hour part (0 to 23) of the time.

    \sa minute(), second(), msec()
*/

int QTime::hour() const
{
    return ds() / MSECS_PER_HOUR;
}

/*!
    Returns the minute part (0 to 59) of the time.

    \sa hour(), second(), msec()
*/

int QTime::minute() const
{
    return (ds() % MSECS_PER_HOUR)/MSECS_PER_MIN;
}

/*!
    Returns the second part (0 to 59) of the time.

    \sa hour(), minute(), msec()
*/

int QTime::second() const
{
    return (ds() / 1000)%SECS_PER_MIN;
}

/*!
    Returns the millisecond part (0 to 999) of the time.

    \sa hour(), minute(), second()