blob: 1ecf8129949739a0477559b80a3b75530fde585a [file] [log] [blame]
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// Dart core library.
// VM implementation of DateTime.
patch class DateTime {
// Natives.
// The natives have been moved up here to work around Issue 10401.
static int _getCurrentMicros() native "DateTime_currentTimeMicros";
static String _timeZoneNameForClampedSeconds(int secondsSinceEpoch)
native "DateTime_timeZoneName";
static int _timeZoneOffsetInSecondsForClampedSeconds(int secondsSinceEpoch)
native "DateTime_timeZoneOffsetInSeconds";
static int _localTimeZoneAdjustmentInSeconds()
native "DateTime_localTimeZoneAdjustmentInSeconds";
static const _MICROSECOND_INDEX = 0;
static const _MILLISECOND_INDEX = 1;
static const _SECOND_INDEX = 2;
static const _MINUTE_INDEX = 3;
static const _HOUR_INDEX = 4;
static const _DAY_INDEX = 5;
static const _WEEKDAY_INDEX = 6;
static const _MONTH_INDEX = 7;
static const _YEAR_INDEX = 8;
List __parts;
/* patch */ DateTime.fromMillisecondsSinceEpoch(int millisecondsSinceEpoch,
{bool isUtc: false})
: this._withValue(
millisecondsSinceEpoch * Duration.MICROSECONDS_PER_MILLISECOND,
isUtc: isUtc);
/* patch */ DateTime.fromMicrosecondsSinceEpoch(int microsecondsSinceEpoch,
{bool isUtc: false})
: this._withValue(microsecondsSinceEpoch, isUtc: isUtc);
/* patch */ DateTime._internal(int year,
int month,
int day,
int hour,
int minute,
int second,
int millisecond,
int microsecond,
bool isUtc)
: this.isUtc = isUtc,
this._value = _brokenDownDateToValue(
year, month, day, hour, minute, second, millisecond, microsecond,
isUtc) {
if (_value == null) throw new ArgumentError();
if (isUtc == null) throw new ArgumentError();
}
/* patch */ DateTime._now()
: isUtc = false,
_value = _getCurrentMicros() {
}
/* patch */ String get timeZoneName {
if (isUtc) return "UTC";
return _timeZoneName(microsecondsSinceEpoch);
}
/* patch */ Duration get timeZoneOffset {
if (isUtc) return new Duration();
int offsetInSeconds = _timeZoneOffsetInSeconds(microsecondsSinceEpoch);
return new Duration(seconds: offsetInSeconds);
}
/** The first list contains the days until each month in non-leap years. The
* second list contains the days in leap years. */
static const List<List<int>> _DAYS_UNTIL_MONTH =
const [const [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334],
const [0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335]];
static List _computeUpperPart(int localMicros) {
const int DAYS_IN_4_YEARS = 4 * 365 + 1;
const int DAYS_IN_100_YEARS = 25 * DAYS_IN_4_YEARS - 1;
const int DAYS_IN_400_YEARS = 4 * DAYS_IN_100_YEARS + 1;
const int DAYS_1970_TO_2000 = 30 * 365 + 7;
const int DAYS_OFFSET = 1000 * DAYS_IN_400_YEARS + 5 * DAYS_IN_400_YEARS -
DAYS_1970_TO_2000;
const int YEARS_OFFSET = 400000;
int resultYear = 0;
int resultMonth = 0;
int resultDay = 0;
// Always round down.
final int daysSince1970 = _flooredDivision(localMicros,
Duration.MICROSECONDS_PER_DAY);
int days = daysSince1970;
days += DAYS_OFFSET;
resultYear = 400 * (days ~/ DAYS_IN_400_YEARS) - YEARS_OFFSET;
days = days.remainder(DAYS_IN_400_YEARS);
days--;
int yd1 = days ~/ DAYS_IN_100_YEARS;
days = days.remainder(DAYS_IN_100_YEARS);
resultYear += 100 * yd1;
days++;
int yd2 = days ~/ DAYS_IN_4_YEARS;
days = days.remainder(DAYS_IN_4_YEARS);
resultYear += 4 * yd2;
days--;
int yd3 = days ~/ 365;
days = days.remainder(365);
resultYear += yd3;
bool isLeap = (yd1 == 0 || yd2 != 0) && yd3 == 0;
if (isLeap) days++;
List<int> daysUntilMonth = _DAYS_UNTIL_MONTH[isLeap ? 1 : 0];
for (resultMonth = 12;
daysUntilMonth[resultMonth - 1] > days;
resultMonth--) {
// Do nothing.
}
resultDay = days - daysUntilMonth[resultMonth - 1] + 1;
int resultMicrosecond = localMicros % Duration.MICROSECONDS_PER_MILLISECOND;
int resultMillisecond =
_flooredDivision(localMicros, Duration.MICROSECONDS_PER_MILLISECOND) %
Duration.MILLISECONDS_PER_SECOND;
int resultSecond =
_flooredDivision(localMicros, Duration.MICROSECONDS_PER_SECOND) %
Duration.SECONDS_PER_MINUTE;
int resultMinute = _flooredDivision(localMicros,
Duration.MICROSECONDS_PER_MINUTE);
resultMinute %= Duration.MINUTES_PER_HOUR;
int resultHour =
_flooredDivision(localMicros, Duration.MICROSECONDS_PER_HOUR);
resultHour %= Duration.HOURS_PER_DAY;
// In accordance with ISO 8601 a week
// starts with Monday. Monday has the value 1 up to Sunday with 7.
// 1970-1-1 was a Thursday.
int resultWeekday = ((daysSince1970 + DateTime.THURSDAY - DateTime.MONDAY) %
DateTime.DAYS_PER_WEEK) + DateTime.MONDAY;
List list = new List(_YEAR_INDEX + 1);
list[_MICROSECOND_INDEX] = resultMicrosecond;
list[_MILLISECOND_INDEX] = resultMillisecond;
list[_SECOND_INDEX] = resultSecond;
list[_MINUTE_INDEX] = resultMinute;
list[_HOUR_INDEX] = resultHour;
list[_DAY_INDEX] = resultDay;
list[_WEEKDAY_INDEX] = resultWeekday;
list[_MONTH_INDEX] = resultMonth;
list[_YEAR_INDEX] = resultYear;
return list;
}
get _parts {
if (__parts == null) {
__parts = _computeUpperPart(_localDateInUtcMicros);
}
return __parts;
}
/* patch */ DateTime add(Duration duration) {
return new DateTime._withValue(
_value + duration.inMicroseconds, isUtc: isUtc);
}
/* patch */ DateTime subtract(Duration duration) {
return new DateTime._withValue(
_value - duration.inMicroseconds, isUtc: isUtc);
}
/* patch */ Duration difference(DateTime other) {
return new Duration(microseconds: _value - other._value);
}
/* patch */ int get millisecondsSinceEpoch =>
_value ~/ Duration.MICROSECONDS_PER_MILLISECOND;
/* patch */ int get microsecondsSinceEpoch => _value;
/* patch */ int get microsecond => _parts[_MICROSECOND_INDEX];
/* patch */ int get millisecond => _parts[_MILLISECOND_INDEX];
/* patch */ int get second => _parts[_SECOND_INDEX];
/* patch */ int get minute => _parts[_MINUTE_INDEX];
/* patch */ int get hour => _parts[_HOUR_INDEX];
/* patch */ int get day => _parts[_DAY_INDEX];
/* patch */ int get weekday => _parts[_WEEKDAY_INDEX];
/* patch */ int get month => _parts[_MONTH_INDEX];
/* patch */ int get year => _parts[_YEAR_INDEX];
/**
* Returns the amount of microseconds in UTC that represent the same values
* as [this].
*
* Say `t` is the result of this function, then
* * `this.year == new DateTime.fromMicrosecondsSinceEpoch(t, true).year`,
* * `this.month == new DateTime.fromMicrosecondsSinceEpoch(t, true).month`,
* * `this.day == new DateTime.fromMicrosecondsSinceEpoch(t, true).day`,
* * `this.hour == new DateTime.fromMicrosecondsSinceEpoch(t, true).hour`,
* * ...
*
* Daylight savings is computed as if the date was computed in [1970..2037].
* If [this] lies outside this range then it is a year with similar
* properties (leap year, weekdays) is used instead.
*/
int get _localDateInUtcMicros {
int micros = _value;
if (isUtc) return micros;
int offset =
_timeZoneOffsetInSeconds(micros) * Duration.MICROSECONDS_PER_SECOND;
return micros + offset;
}
static int _flooredDivision(int a, int b) {
return (a - (a < 0 ? b - 1 : 0)) ~/ b;
}
// Returns the days since 1970 for the start of the given [year].
// [year] may be before epoch.
static int _dayFromYear(int year) {
return 365 * (year - 1970)
+ _flooredDivision(year - 1969, 4)
- _flooredDivision(year - 1901, 100)
+ _flooredDivision(year - 1601, 400);
}
static bool _isLeapYear(y) {
// (y % 16 == 0) matches multiples of 400, and is faster than % 400.
return (y % 4 == 0) && ((y % 16 == 0) || (y % 100 != 0));
}
/// Converts the given broken down date to microseconds.
/* patch */ static int _brokenDownDateToValue(
int year, int month, int day,
int hour, int minute, int second, int millisecond, int microsecond,
bool isUtc) {
// Simplify calculations by working with zero-based month.
--month;
// Deal with under and overflow.
if (month >= 12) {
year += month ~/ 12;
month = month % 12;
} else if (month < 0) {
int realMonth = month % 12;
year += (month - realMonth) ~/ 12;
month = realMonth;
}
// First compute the seconds in UTC, independent of the [isUtc] flag. If
// necessary we will add the time-zone offset later on.
int days = day - 1;
days += _DAYS_UNTIL_MONTH[_isLeapYear(year) ? 1 : 0][month];
days += _dayFromYear(year);
int microsecondsSinceEpoch =
days * Duration.MICROSECONDS_PER_DAY +
hour * Duration.MICROSECONDS_PER_HOUR +
minute * Duration.MICROSECONDS_PER_MINUTE +
second * Duration.MICROSECONDS_PER_SECOND +
millisecond * Duration.MICROSECONDS_PER_MILLISECOND +
microsecond;
// Since [_timeZoneOffsetInSeconds] will crash if the input is far out of
// the valid range we do a preliminary test that weeds out values that can
// not become valid even with timezone adjustments.
// The timezone adjustment is always less than a day, so adding a security
// margin of one day should be enough.
if (microsecondsSinceEpoch.abs() >
_MAX_MILLISECONDS_SINCE_EPOCH * 1000 + Duration.MICROSECONDS_PER_DAY) {
return null;
}
if (!isUtc) {
// Note that we need to remove the local timezone adjustment before
// asking for the correct zone offset.
int adjustment = _localTimeZoneAdjustmentInSeconds() *
Duration.MICROSECONDS_PER_SECOND;
// The adjustment is independent of the actual date and of the daylight
// saving time. It is positive east of the Prime Meridian and negative
// west of it, e.g. -28800 sec for America/Los_Angeles timezone.
int zoneOffset =
_timeZoneOffsetInSeconds(microsecondsSinceEpoch - adjustment);
// The zoneOffset depends on the actual date and reflects any daylight
// saving time and/or historical deviation relative to UTC time.
// It is positive east of the Prime Meridian and negative west of it,
// e.g. -25200 sec for America/Los_Angeles timezone during DST.
microsecondsSinceEpoch -= zoneOffset * Duration.MICROSECONDS_PER_SECOND;
// The resulting microsecondsSinceEpoch value is therefore the calculated
// UTC value decreased by a (positive if east of GMT) timezone adjustment
// and decreased by typically one hour if DST is in effect.
}
if (microsecondsSinceEpoch.abs() >
_MAX_MILLISECONDS_SINCE_EPOCH * Duration.MICROSECONDS_PER_MILLISECOND) {
return null;
}
return microsecondsSinceEpoch;
}
static int _weekDay(y) {
// 1/1/1970 was a Thursday.
return (_dayFromYear(y) + 4) % 7;
}
/**
* Returns a year in the range 2008-2035 matching
* * leap year, and
* * week day of first day.
*
* Leap seconds are ignored.
* Adapted from V8's date implementation. See ECMA 262 - 15.9.1.9.
*/
static int _equivalentYear(int year) {
// Returns year y so that _weekDay(y) == _weekDay(year).
// _weekDay returns the week day (in range 0 - 6).
// 1/1/1956 was a Sunday (i.e. weekday 0). 1956 was a leap-year.
// 1/1/1967 was a Sunday (i.e. weekday 0).
// Without leap years a subsequent year has a week day + 1 (for example
// 1/1/1968 was a Monday). With leap-years it jumps over one week day
// (e.g. 1/1/1957 was a Tuesday).
// After 12 years the weekdays have advanced by 12 days + 3 leap days =
// 15 days. 15 % 7 = 1. So after 12 years the week day has always
// (now independently of leap-years) advanced by one.
// weekDay * 12 gives thus a year starting with the wanted weekDay.
int recentYear = (_isLeapYear(year) ? 1956 : 1967) + (_weekDay(year) * 12);
// Close to the year 2008 the calendar cycles every 4 * 7 years (4 for the
// leap years, 7 for the weekdays).
// Find the year in the range 2008..2037 that is equivalent mod 28.
return 2008 + (recentYear - 2008) % 28;
}
/**
* Returns the UTC year for the corresponding [secondsSinceEpoch].
* It is relatively fast for values in the range 0 to year 2098.
*
* Code is adapted from V8.
*/
static int _yearsFromSecondsSinceEpoch(int secondsSinceEpoch) {
const int DAYS_IN_4_YEARS = 4 * 365 + 1;
const int DAYS_IN_100_YEARS = 25 * DAYS_IN_4_YEARS - 1;
const int DAYS_YEAR_2098 = DAYS_IN_100_YEARS + 6 * DAYS_IN_4_YEARS;
int days = secondsSinceEpoch ~/ Duration.SECONDS_PER_DAY;
if (days > 0 && days < DAYS_YEAR_2098) {
// According to V8 this fast case works for dates from 1970 to 2099.
return 1970 + (4 * days + 2) ~/ DAYS_IN_4_YEARS;
}
int micros = secondsSinceEpoch * Duration.MICROSECONDS_PER_SECOND;
return _computeUpperPart(micros)[_YEAR_INDEX];
}
/**
* Returns a date in seconds that is equivalent to the given
* date in microseconds [microsecondsSinceEpoch]. An equivalent
* date has the same fields (`month`, `day`, etc.) as the given
* date, but the `year` is in the range [1901..2038].
*
* * The time since the beginning of the year is the same.
* * If the given date is in a leap year then the returned
* seconds are in a leap year, too.
* * The week day of given date is the same as the one for the
* returned date.
*/
static int _equivalentSeconds(int microsecondsSinceEpoch) {
const int CUT_OFF_SECONDS = 0x7FFFFFFF;
int secondsSinceEpoch = _flooredDivision(microsecondsSinceEpoch,
Duration.MICROSECONDS_PER_SECOND);
if (secondsSinceEpoch.abs() > CUT_OFF_SECONDS) {
int year = _yearsFromSecondsSinceEpoch(secondsSinceEpoch);
int days = _dayFromYear(year);
int equivalentYear = _equivalentYear(year);
int equivalentDays = _dayFromYear(equivalentYear);
int diffDays = equivalentDays - days;
secondsSinceEpoch += diffDays * Duration.SECONDS_PER_DAY;
}
return secondsSinceEpoch;
}
static int _timeZoneOffsetInSeconds(int microsecondsSinceEpoch) {
int equivalentSeconds = _equivalentSeconds(microsecondsSinceEpoch);
return _timeZoneOffsetInSecondsForClampedSeconds(equivalentSeconds);
}
static String _timeZoneName(int microsecondsSinceEpoch) {
int equivalentSeconds = _equivalentSeconds(microsecondsSinceEpoch);
return _timeZoneNameForClampedSeconds(equivalentSeconds);
}
}