qdatetime.cpp

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

    Note that the time will wrap if it passes midnight. See addSecs()
    for an example.

    \sa addSecs(), msecsTo()
*/

QTime QTime::addMSecs( int ms ) const
{
    QTime t;
    if ( ms < 0 ) {
	// % not well-defined for -ve, but / is.
	int negdays = (MSECS_PER_DAY-ms) / MSECS_PER_DAY;
	t.ds = ((int)ds + ms + negdays*MSECS_PER_DAY)
		% MSECS_PER_DAY;
    } else {
	t.ds = ((int)ds + ms) % MSECS_PER_DAY;
    }
    return t;
}

/*!
    Returns the number of milliseconds from this time to \a t (which
    is negative if \a t is earlier than this time).

    Because QTime measures time within a day and there are 86400
    seconds in a day, the result is always between -86400 and 86400s.

    \sa secsTo()
*/

int QTime::msecsTo( const QTime &t ) const
{
    return (int)t.ds - (int)ds;
}


/*!
    \fn bool QTime::operator==( const QTime &t ) const

    Returns TRUE if this time is equal to \a t; otherwise returns FALSE.
*/

/*!
    \fn bool QTime::operator!=( const QTime &t ) const

    Returns TRUE if this time is different from \a t; otherwise returns FALSE.
*/

/*!
    \fn bool QTime::operator<( const QTime &t ) const

    Returns TRUE if this time is earlier than \a t; otherwise returns FALSE.
*/

/*!
    \fn bool QTime::operator<=( const QTime &t ) const

    Returns TRUE if this time is earlier than or equal to \a t;
    otherwise returns FALSE.
*/

/*!
    \fn bool QTime::operator>( const QTime &t ) const

    Returns TRUE if this time is later than \a t; otherwise returns FALSE.
*/

/*!
    \fn bool QTime::operator>=( const QTime &t ) const

    Returns TRUE if this time is later than or equal to \a t;
    otherwise returns FALSE.
*/



/*!
    \overload

    Returns the current time as reported by the system clock.

    Note that the accuracy depends on the accuracy of the underlying
    operating system; not all systems provide 1-millisecond accuracy.
*/

QTime QTime::currentTime()
{
    return currentTime( Qt::LocalTime );
}

/*!
  Returns the current time as reported by the system clock, for the
  TimeSpec \a ts. The default TimeSpec is LocalTime.

  Note that the accuracy depends on the accuracy of the underlying
  operating system; not all systems provide 1-millisecond accuracy.

  \sa Qt::TimeSpec
*/
QTime QTime::currentTime( Qt::TimeSpec ts )
{
    QTime t;
    currentTime( &t, ts );
    return t;
}

#ifndef QT_NO_DATESTRING
/*!
    Returns the representation \a s as a QTime using the format \a f,
    or an invalid time if this is not possible.

    \warning Note that \c Qt::LocalDate cannot be used here.
*/
QTime QTime::fromString( const QString& s, Qt::DateFormat f )
{
    if ( ( s.isEmpty() ) || ( f == Qt::LocalDate ) ) {
#if defined(QT_CHECK_RANGE)
	qWarning( "QTime::fromString: Parameter out of range" );
#endif
	QTime t;
	t.ds = MSECS_PER_DAY;
	return t;
    }

    int hour( s.mid( 0, 2 ).toInt() );
    int minute( s.mid( 3, 2 ).toInt() );
    int second( s.mid( 6, 2 ).toInt() );
    int msec( s.mid( 9, 3 ).toInt() );
    return QTime( hour, minute, second, msec );
}
#endif

/*!
  \internal
  \obsolete

  Fetches the current time and returns TRUE if the time is within one
  minute after midnight, otherwise FALSE. The return value is used by
  QDateTime::currentDateTime() to ensure that the date there is correct.
*/

bool QTime::currentTime( QTime *ct )
{
    return currentTime( ct, Qt::LocalTime );
}


/*!
  \internal

  Fetches the current time, for the TimeSpec \a ts, and returns TRUE
  if the time is within one minute after midnight, otherwise FALSE. The
  return value is used by QDateTime::currentDateTime() to ensure that
  the date there is correct. The default TimeSpec is LocalTime.

  \sa Qt::TimeSpec
*/
bool QTime::currentTime( QTime *ct, Qt::TimeSpec ts )
{
    if ( !ct ) {
#if defined(QT_CHECK_NULL)
	qWarning( "QTime::currentTime(QTime *): Null pointer not allowed" );
#endif
	return FALSE;
    }

#if defined(Q_OS_WIN32)
    SYSTEMTIME t;
    if ( ts == Qt::LocalTime ) {
	GetLocalTime( &t );
    } else {
	GetSystemTime( &t );
    }
    ct->ds = (uint)( MSECS_PER_HOUR*t.wHour + MSECS_PER_MIN*t.wMinute +
		     1000*t.wSecond + t.wMilliseconds );
#elif defined(Q_OS_UNIX)
    // posix compliant system
    struct timeval tv;
    gettimeofday( &tv, 0 );
    time_t ltime = tv.tv_sec;
    tm *t;

#  if defined(QT_THREAD_SUPPORT) && defined(_POSIX_THREAD_SAFE_FUNCTIONS)
    // use the reentrant versions of localtime() and gmtime() where available
    tm res;
    if ( ts == Qt::LocalTime )
	t = localtime_r( &ltime, &res );
    else
	t = gmtime_r( &ltime, &res );
#  else
    if ( ts == Qt::LocalTime )
	t = localtime( &ltime );
    else
	t = gmtime( &ltime );
#  endif // QT_THREAD_SUPPORT && _POSIX_THREAD_SAFE_FUNCTIONS

    ct->ds = (uint)( MSECS_PER_HOUR * t->tm_hour + MSECS_PER_MIN * t->tm_min +
		     1000 * t->tm_sec + tv.tv_usec / 1000 );
#else
    time_t ltime; // no millisecond resolution
    ::time( &ltime );
    tm *t;
    if ( ts == Qt::LocalTime )
	localtime( &ltime );
    else
	gmtime( &ltime );
    ct->ds = (uint) ( MSECS_PER_HOUR * t->tm_hour + MSECS_PER_MIN * t->tm_min +
		      1000 * t->tm_sec );
#endif
    // 00:00.00 to 00:00.59.999 is considered as "midnight or right after"
    return ct->ds < (uint) MSECS_PER_MIN;
}

/*!
    \overload

    Returns TRUE if the specified time is valid; otherwise returns
    FALSE.

    The time is valid if \a h is in the range 0..23, \a m and \a s are
    in the range 0..59, and \a ms is in the range 0..999.

    Example:
    \code
    QTime::isValid(21, 10, 30); // returns TRUE
    QTime::isValid(22, 5,  62); // returns FALSE
    \endcode
*/

bool QTime::isValid( int h, int m, int s, int ms )
{
    return (uint)h < 24 && (uint)m < 60 && (uint)s < 60 && (uint)ms < 1000;
}


/*!
    Sets this time to the current time. This is practical for timing:

    \code
    QTime t;
    t.start();
    some_lengthy_task();
    qDebug( "Time elapsed: %d ms", t.elapsed() );
    \endcode

    \sa restart(), elapsed(), currentTime()
*/

void QTime::start()
{
    *this = currentTime();
}

/*!
    Sets this time to the current time and returns the number of
    milliseconds that have elapsed since the last time start() or
    restart() was called.

    This function is guaranteed to be atomic and is thus very handy
    for repeated measurements. Call start() to start the first
    measurement and then restart() for each later measurement.

    Note that the counter wraps to zero 24 hours after the last call
    to start() or restart().

    \warning If the system's clock setting has been changed since the
    last time start() or restart() was called, the result is
    undefined. This can happen when daylight savings time is turned on
    or off.

    \sa start(), elapsed(), currentTime()
*/

int QTime::restart()
{
    QTime t = currentTime();
    int n = msecsTo( t );
    if ( n < 0 )				// passed midnight
	n += 86400*1000;
    *this = t;
    return n;
}

/*!
    Returns the number of milliseconds that have elapsed since the
    last time start() or restart() was called.

    Note that the counter wraps to zero 24 hours after the last call
    to start() or restart.

    Note that the accuracy depends on the accuracy of the underlying
    operating system; not all systems provide 1-millisecond accuracy.

    \warning If the system's clock setting has been changed since the
    last time start() or restart() was called, the result is
    undefined. This can happen when daylight savings time is turned on
    or off.

    \sa start(), restart()
*/

int QTime::elapsed() const
{
    int n = msecsTo( currentTime() );
    if ( n < 0 )				// passed midnight
	n += 86400*1000;
    return n;
}


/*****************************************************************************
  QDateTime member functions
 *****************************************************************************/

/*!
    \class QDateTime qdatetime.h
    \reentrant
    \brief The QDateTime class provides date and time functions.

    \ingroup time
    \mainclass

    A QDateTime object contains a calendar date and a clock time (a
    "datetime"). It is a combination of the QDate and QTime classes.
    It can read the current datetime from the system clock. It
    provides functions for comparing datetimes and for manipulating a
    datetime by adding a number of seconds, days, months or years.

    A QDateTime object is typically created either by giving a date
    and time explicitly in the constructor, or by using the static
    function currentDateTime(), which returns a QDateTime object set
    to the system clock's time. The date and time can be changed with
    setDate() and setTime(). A datetime can also be set using the
    setTime_t() function, which takes a POSIX-standard "number of
    seconds since 00:00:00 on January 1, 1970" value. The fromString()
    function returns a QDateTime given a string and a date format
    which is used to interpret the date within the string.

    The date() and time() functions provide access to the date and
    time parts of the datetime. The same information is provided in
    textual format by the toString() function.

    QDateTime provides a full set of operators to compare two
    QDateTime objects where smaller means earlier and larger means
    later.

    You can increment (or decrement) a datetime by a given number of
    seconds using addSecs() or days using addDays(). Similarly you can
    use addMonths() and addYears(). The daysTo() function returns the
    number of days between two datetimes, and secsTo() returns the
    number of seconds between two datetimes.

    The range of a datetime object is constrained to the ranges of the
    QDate and QTime objects which it embodies.

    \sa QDate QTime QDateTimeEdit
*/


/*!
    \fn QDateTime::QDateTime()

    Constructs a null datetime (i.e. null date and null time). A null
    datetime is invalid, since the date is invalid.

    \sa isValid()
*/


/*!
    Constructs a datetime with date \a date and null (but valid) time
    (00:00:00.000).
*/

QDateTime::QDateTime( const QDate &date )
    : d(date)
{
}

/*!
    Constructs a datetime with date \a date and time \a time.
*/

QDateTime::QDateTime( const QDate &date, const QTime &time )
    : d(date), t(time)
{
}


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

    Returns TRUE if both the date and the time are null; otherwise
    returns FALSE. A null datetime is invalid.

    \sa QDate::isNull(), QTime::isNull()
*/

/*!
    \fn bool QDateTime::isValid() const

    Returns TRUE if both the date and the time are valid; otherwise
    returns FALSE.

    \sa QDate::isValid(), QTime::isValid()
*/

/*!
    \fn QDate QDateTime::date() const

    Returns the date part of the datetime.

    \sa setDate(), time()
*/

/*!
    \fn QTime QDateTime::time() const

    Returns the time part of the datetime.

    \sa setTime(), date()
*/

/*!
    \fn void QDateTime::setDate( const QDate &date )

    Sets the date part of this datetime to \a date.

    \sa date(), setTime()
*/

/*!
    \fn void QDateTime::setTime( const QTime &time )

    Sets the time part of this datetime to \a time.

    \sa time(), setDate()
*/


/*!
    Returns the datetime as the number of seconds that have passed
    since 1970-01-01T00:00:00, Coordinated Universal Time (UTC).

    On systems that do not support timezones, this function will
    behave as if local time were UTC.

    \sa setTime_t()
*/

uint QDateTime::toTime_t() const
{
    tm brokenDown;
    brokenDown.tm_sec = t.second();
    brokenDown.tm_min = t.minute();
    brokenDown.tm_hour = t.hour();
    brokenDown.tm_mday = d.day();
    brokenDown.tm_mon = d.month() - 1;
    brokenDown.tm_year = d.year() - 1900;
    brokenDown.tm_isdst = -1;
    int secsSince1Jan1970UTC = (int) mktime( &brokenDown );
    if ( secsSince1Jan1970UTC < -1 )
	secsSince1Jan1970UTC = -1;
    return (uint) secsSince1Jan1970UTC;
}

/*!
    \overload

    Convenience function that sets the date and time to local time
    based on the given UTC time.
*/

void QDateTime::setTime_t( uint secsSince1Jan1970UTC )
{
    setTime_t( secsSince1Jan1970UTC, Qt::LocalTime );
}

/*!
    Sets the date and time to \a ts time (\c Qt::LocalTime or \c
    Qt::UTC) given the number of seconds that have passed since
    1970-01-01T00:00:00, Coordinated Universal Time (UTC). On systems
    that do not support timezones this function will behave as if
    local time were UTC.

    On Windows, only a subset of \a secsSince1Jan1970UTC values are
    supported, as Windows starts counting from 1980.

    \sa toTime_t()
*/
void QDateTime::setTime_t( uint secsSince1Jan1970UTC, Qt::TimeSpec ts )
{
    time_t tmp = (time_t) secsSince1Jan1970UTC;
    tm *brokenDown = 0;

#if defined(Q_OS_UNIX) && defined(QT_THREAD_SUPPORT) && defined(_POSIX_THREAD_SAFE_FUNCTIONS)
    // posix compliant system
    // use the reentrant versions of localtime() and gmtime() where available
    tm res;
    if ( ts == Qt::LocalTime )
	brokenDown = localtime_r( &tmp, &res );
    if ( !brokenDown ) {
	brokenDown = gmtime_r( &tmp, &res );
	if ( !brokenDown ) {
	    d.jd = QDate::gregorianToJulian( 1970, 1, 1 );
	    t.ds = 0;