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qwt_date.cpp
/******************************************************************************
* Qwt Widget Library
* Copyright (C) 1997 Josef Wilgen
* Copyright (C) 2002 Uwe Rathmann
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the Qwt License, Version 1.0
*****************************************************************************/
#include "qwt_date.h"
#include "qwt_math.h"
#include <qdebug.h>
#include <qlocale.h>
#include <limits>
#if QT_VERSION >= 0x050000
typedef qint64 QwtJulianDay;
static const QwtJulianDay minJulianDayD = Q_INT64_C( -784350574879 );
static const QwtJulianDay maxJulianDayD = Q_INT64_C( 784354017364 );
#else
// QDate stores the Julian day as unsigned int, but
// there is QDate::fromJulianDay( int ). That's why
// we have the range [ 1, INT_MAX ]
typedef int QwtJulianDay;
static const QwtJulianDay minJulianDayD = 1;
static const QwtJulianDay maxJulianDayD = std::numeric_limits< int >::max();
#endif
static QString qwtExpandedFormat( const QString& format,
const QDateTime& dateTime, QwtDate::Week0Type week0Type )
{
const int week = QwtDate::weekNumber( dateTime.date(), week0Type );
QString weekNo;
weekNo.setNum( week );
QString weekNoWW;
if ( weekNo.length() == 1 )
weekNoWW += QLatin1Char( '0' );
weekNoWW += weekNo;
QString fmt = format;
fmt.replace( QLatin1String( "ww" ), weekNoWW );
fmt.replace( QLatin1Char( 'w' ), weekNo );
if ( week == 1 && dateTime.date().month() != 1 )
{
// in case of week 1, we might need to increment the year
QLatin1String s_yyyy( "yyyy" );
QLatin1String s_yy( "yy" );
// week 1 might start in the previous year
bool doReplaceYear = fmt.contains( s_yy );
if ( doReplaceYear )
{
if ( fmt.contains( 'M' ) )
{
// in case of also having 'M' we have a conflict about
// which year to show
doReplaceYear = false;
}
else
{
// in case of also having 'd' or 'dd' we have a conflict about
// which year to show
int numD = 0;
for ( int i = 0; i < fmt.size(); i++ )
{
if ( fmt[i] == 'd' )
{
numD++;
}
else
{
if ( numD > 0 && numD <= 2 )
break;
numD = 0;
}
}
if ( numD > 0 && numD <= 2 )
doReplaceYear = false;
}
}
if ( doReplaceYear )
{
const QDate dt( dateTime.date().year() + 1, 1, 1 );
const QString dtString = QLocale().toString( dt, s_yyyy );
if ( fmt.contains( s_yyyy ) )
{
fmt.replace( s_yyyy, dtString );
}
else
{
fmt.replace( s_yy, dtString );
}
}
}
return fmt;
}
static inline Qt::DayOfWeek qwtFirstDayOfWeek()
{
return QLocale().firstDayOfWeek();
}
static inline void qwtFloorTime(
QwtDate::IntervalType intervalType, QDateTime& dt )
{
// when dt is inside the special hour where DST is ending
// an hour is no unique. Therefore we have to
// use UTC time.
const Qt::TimeSpec timeSpec = dt.timeSpec();
if ( timeSpec == Qt::LocalTime )
dt = dt.toTimeSpec( Qt::UTC );
const QTime t = dt.time();
switch( intervalType )
{
case QwtDate::Second:
{
dt.setTime( QTime( t.hour(), t.minute(), t.second() ) );
break;
}
case QwtDate::Minute:
{
dt.setTime( QTime( t.hour(), t.minute(), 0 ) );
break;
}
case QwtDate::Hour:
{
dt.setTime( QTime( t.hour(), 0, 0 ) );
break;
}
default:
break;
}
if ( timeSpec == Qt::LocalTime )
dt = dt.toTimeSpec( Qt::LocalTime );
}
static inline QDateTime qwtToTimeSpec(
const QDateTime& dt, Qt::TimeSpec spec )
{
if ( dt.timeSpec() == spec )
return dt;
const qint64 jd = dt.date().toJulianDay();
if ( jd < 0 || jd >= std::numeric_limits< int >::max() )
{
// the conversion between local time and UTC
// is internally limited. To avoid
// overflows we simply ignore the difference
// for those dates
QDateTime dt2 = dt;
dt2.setTimeSpec( spec );
return dt2;
}
return dt.toTimeSpec( spec );
}
#if 0
static inline double qwtToJulianDay( int year, int month, int day )
{
// code from QDate but using doubles to avoid overflows
// for large values
const int m1 = ( month - 14 ) / 12;
const int m2 = ( 367 * ( month - 2 - 12 * m1 ) ) / 12;
const double y1 = std::floor( ( 4900.0 + year + m1 ) / 100 );
return std::floor( ( 1461.0 * ( year + 4800 + m1 ) ) / 4 ) + m2
- std::floor( ( 3 * y1 ) / 4 ) + day - 32075;
}
static inline qint64 qwtFloorDiv64( qint64 a, int b )
{
if ( a < 0 )
a -= b - 1;
return a / b;
}
static inline qint64 qwtFloorDiv( int a, int b )
{
if ( a < 0 )
a -= b - 1;
return a / b;
}
#endif
static inline QDate qwtToDate( int year, int month = 1, int day = 1 )
{
#if QT_VERSION >= 0x050000
return QDate( year, month, day );
#else
if ( year > 100000 )
{
// code from QDate but using doubles to avoid overflows
// for large values
const int m1 = ( month - 14 ) / 12;
const int m2 = ( 367 * ( month - 2 - 12 * m1 ) ) / 12;
const double y1 = std::floor( ( 4900.0 + year + m1 ) / 100 );
const double jd = std::floor( ( 1461.0 * ( year + 4800 + m1 ) ) / 4 ) + m2
- std::floor( ( 3 * y1 ) / 4 ) + day - 32075;
if ( jd > maxJulianDayD )
{
qWarning() << "qwtToDate: overflow";
return QDate();
}
return QDate::fromJulianDay( static_cast< QwtJulianDay >( jd ) );
}
else
{
return QDate( year, month, day );
}
#endif
}
QDateTime QwtDate::toDateTime( double value, Qt::TimeSpec timeSpec )
{
const int msecsPerDay = 86400000;
const double days = static_cast< qint64 >( std::floor( value / msecsPerDay ) );
const double jd = QwtDate::JulianDayForEpoch + days;
if ( ( jd > maxJulianDayD ) || ( jd < minJulianDayD ) )
{
qWarning() << "QwtDate::toDateTime: overflow";
return QDateTime();
}
const QDate d = QDate::fromJulianDay( static_cast< QwtJulianDay >( jd ) );
const int msecs = static_cast< int >( value - days * msecsPerDay );
static const QTime timeNull( 0, 0, 0, 0 );
QDateTime dt( d, timeNull.addMSecs( msecs ), Qt::UTC );
if ( timeSpec == Qt::LocalTime )
dt = qwtToTimeSpec( dt, timeSpec );
return dt;
}
double QwtDate::toDouble( const QDateTime& dateTime )
{
const int msecsPerDay = 86400000;
const QDateTime dt = qwtToTimeSpec( dateTime, Qt::UTC );
const double days = dt.date().toJulianDay() - QwtDate::JulianDayForEpoch;
const QTime time = dt.time();
const double secs = 3600.0 * time.hour() +
60.0 * time.minute() + time.second();
return days * msecsPerDay + time.msec() + 1000.0 * secs;
}
QDateTime QwtDate::ceil( const QDateTime& dateTime, IntervalType intervalType )
{
if ( dateTime.date() >= QwtDate::maxDate() )
return dateTime;
QDateTime dt = dateTime;
switch ( intervalType )
{
case QwtDate::Millisecond:
{
break;
}
case QwtDate::Second:
{
qwtFloorTime( QwtDate::Second, dt );
if ( dt < dateTime )
dt = dt.addSecs( 1 );
break;
}
case QwtDate::Minute:
{
qwtFloorTime( QwtDate::Minute, dt );
if ( dt < dateTime )
dt = dt.addSecs( 60 );
break;
}
case QwtDate::Hour:
{
qwtFloorTime( QwtDate::Hour, dt );
if ( dt < dateTime )
dt = dt.addSecs( 3600 );
break;
}
case QwtDate::Day:
{
dt.setTime( QTime( 0, 0 ) );
if ( dt < dateTime )
dt = dt.addDays( 1 );
break;
}
case QwtDate::Week:
{
dt.setTime( QTime( 0, 0 ) );
if ( dt < dateTime )
dt = dt.addDays( 1 );
int days = qwtFirstDayOfWeek() - dt.date().dayOfWeek();
if ( days < 0 )
days += 7;
dt = dt.addDays( days );
break;
}
case QwtDate::Month:
{
dt.setTime( QTime( 0, 0 ) );
dt.setDate( qwtToDate( dateTime.date().year(),
dateTime.date().month() ) );
if ( dt < dateTime )
dt = dt.addMonths( 1 );
break;
}
case QwtDate::Year:
{
dt.setTime( QTime( 0, 0 ) );
const QDate d = dateTime.date();
int year = d.year();
if ( d.month() > 1 || d.day() > 1 || !dateTime.time().isNull() )
year++;
if ( year == 0 )
year++; // there is no year 0
dt.setDate( qwtToDate( year ) );
break;
}
}
return dt;
}
QDateTime QwtDate::floor( const QDateTime& dateTime,
IntervalType intervalType )
{
if ( dateTime.date() <= QwtDate::minDate() )
return dateTime;
QDateTime dt = dateTime;
switch ( intervalType )
{
case QwtDate::Millisecond:
{
break;
}
case QwtDate::Second:
case QwtDate::Minute:
case QwtDate::Hour:
{
qwtFloorTime( intervalType, dt );
break;
}
case QwtDate::Day:
{
dt.setTime( QTime( 0, 0 ) );
break;
}
case QwtDate::Week:
{
dt.setTime( QTime( 0, 0 ) );
int days = dt.date().dayOfWeek() - qwtFirstDayOfWeek();
if ( days < 0 )
days += 7;
dt = dt.addDays( -days );
break;
}
case QwtDate::Month:
{
dt.setTime( QTime( 0, 0 ) );
const QDate date = qwtToDate( dt.date().year(),
dt.date().month() );
dt.setDate( date );
break;
}
case QwtDate::Year:
{
dt.setTime( QTime( 0, 0 ) );
const QDate date = qwtToDate( dt.date().year() );
dt.setDate( date );
break;
}
}
return dt;
}
QDate QwtDate::minDate()
{
static QDate date;
if ( !date.isValid() )
date = QDate::fromJulianDay( minJulianDayD );
return date;
}
QDate QwtDate::maxDate()
{
static QDate date;
if ( !date.isValid() )
date = QDate::fromJulianDay( maxJulianDayD );
return date;
}
QDate QwtDate::dateOfWeek0( int year, Week0Type type )
{
const Qt::DayOfWeek firstDayOfWeek = qwtFirstDayOfWeek();
QDate dt0( year, 1, 1 );
// floor to the first day of the week
int days = dt0.dayOfWeek() - firstDayOfWeek;
if ( days < 0 )
days += 7;
dt0 = dt0.addDays( -days );
if ( type == QwtDate::FirstThursday )
{
// according to ISO 8601 the first week is defined
// by the first Thursday.
int d = Qt::Thursday - firstDayOfWeek;
if ( d < 0 )
d += 7;
if ( dt0.addDays( d ).year() < year )
dt0 = dt0.addDays( 7 );
}
return dt0;
}
int QwtDate::weekNumber( const QDate& date, Week0Type type )
{
int weekNo;
if ( type == QwtDate::FirstDay )
{
QDate day0;
if ( date.month() == 12 && date.day() >= 24 )
{
// week 1 usually starts in the previous years.
// and we have to check if we are already there
day0 = dateOfWeek0( date.year() + 1, type );
if ( day0.daysTo( date ) < 0 )
day0 = dateOfWeek0( date.year(), type );
}
else
{
day0 = dateOfWeek0( date.year(), type );
}
weekNo = day0.daysTo( date ) / 7 + 1;
}
else
{
weekNo = date.weekNumber();
}
return weekNo;
}
int QwtDate::utcOffset( const QDateTime& dateTime )
{
int seconds = 0;
switch( dateTime.timeSpec() )
{
case Qt::UTC:
{
break;
}
case Qt::OffsetFromUTC:
{
#if QT_VERSION >= 0x050200
seconds = dateTime.offsetFromUtc();
#else
seconds = dateTime.utcOffset();
#endif
break;
}
default:
{
const QDateTime dt1( dateTime.date(), dateTime.time(), Qt::UTC );
seconds = dateTime.secsTo( dt1 );
}
}
return seconds;
}
QString QwtDate::toString( const QDateTime& dateTime,
const QString& format, Week0Type week0Type )
{
QString fmt = format;
if ( fmt.contains( 'w' ) )
{
fmt = qwtExpandedFormat( fmt, dateTime, week0Type );
}
return QLocale().toString( dateTime, fmt );
}
QwtDate::floor
static QDateTime floor(const QDateTime &, IntervalType)
Definition qwt_date.cpp:425
QwtDate::toString
static QString toString(const QDateTime &, const QString &format, Week0Type)
Definition qwt_date.cpp:686
QwtDate::JulianDayForEpoch
@ JulianDayForEpoch
The Julian day of "The Epoch".
Definition qwt_date.h:105
QwtDate::toDateTime
static QDateTime toDateTime(double value, Qt::TimeSpec=Qt::UTC)
Definition qwt_date.cpp:261
QwtDate::weekNumber
static int weekNumber(const QDate &, Week0Type)
Definition qwt_date.cpp:585
QwtDate::minDate
static QDate minDate()
Definition qwt_date.cpp:499
QwtDate::ceil
static QDateTime ceil(const QDateTime &, IntervalType)
Definition qwt_date.cpp:323
QwtDate::Week0Type
Week0Type
Definition qwt_date.h:50
QwtDate::FirstThursday
@ FirstThursday
Definition qwt_date.h:58
QwtDate::FirstDay
@ FirstDay
Definition qwt_date.h:66
QwtDate::dateOfWeek0
static QDate dateOfWeek0(int year, Week0Type)
Date of the first day of the first week for a year.
Definition qwt_date.cpp:542
QwtDate::IntervalType
IntervalType
Definition qwt_date.h:76
QwtDate::Month
@ Month
The interval is related to months.
Definition qwt_date.h:96
QwtDate::Day
@ Day
The interval is related to days.
Definition qwt_date.h:90
QwtDate::Millisecond
@ Millisecond
The interval is related to milliseconds.
Definition qwt_date.h:78
QwtDate::Minute
@ Minute
The interval is related to minutes.
Definition qwt_date.h:84
QwtDate::Hour
@ Hour
The interval is related to hours.
Definition qwt_date.h:87
QwtDate::Second
@ Second
The interval is related to seconds.
Definition qwt_date.h:81
QwtDate::Week
@ Week
The interval is related to weeks.
Definition qwt_date.h:93
QwtDate::Year
@ Year
The interval is related to years.
Definition qwt_date.h:99
QwtDate::utcOffset
static int utcOffset(const QDateTime &)
Definition qwt_date.cpp:635
QwtDate::maxDate
static QDate maxDate()
Definition qwt_date.cpp:521
QwtDate::toDouble
static double toDouble(const QDateTime &)
Definition qwt_date.cpp:298