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// 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.
// part of "core_patch.dart";
// 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.microsecondsPerMillisecond,
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);
}
@patch
bool operator ==(dynamic other) =>
other is DateTime &&
_value == other.microsecondsSinceEpoch &&
isUtc == other.isUtc;
@patch
bool isBefore(DateTime other) => _value < other.microsecondsSinceEpoch;
@patch
bool isAfter(DateTime other) => _value > other.microsecondsSinceEpoch;
@patch
bool isAtSameMomentAs(DateTime other) =>
_value == other.microsecondsSinceEpoch;
@patch
int compareTo(DateTime other) =>
_value.compareTo(other.microsecondsSinceEpoch);
/** 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.microsecondsPerDay);
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.microsecondsPerMillisecond;
int resultMillisecond =
_flooredDivision(localMicros, Duration.microsecondsPerMillisecond) %
Duration.millisecondsPerSecond;
int resultSecond =
_flooredDivision(localMicros, Duration.microsecondsPerSecond) %
Duration.secondsPerMinute;
int resultMinute =
_flooredDivision(localMicros, Duration.microsecondsPerMinute);
resultMinute %= Duration.minutesPerHour;
int resultHour =
_flooredDivision(localMicros, Duration.microsecondsPerHour);
resultHour %= Duration.hoursPerDay;
// 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.daysPerWeek) +
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 {
__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.microsecondsPerMillisecond;
@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.microsecondsPerSecond;
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.microsecondsPerDay +
hour * Duration.microsecondsPerHour +
minute * Duration.microsecondsPerMinute +
second * Duration.microsecondsPerSecond +
millisecond * Duration.microsecondsPerMillisecond +
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() >
_maxMillisecondsSinceEpoch * 1000 + Duration.microsecondsPerDay) {
return null;
}
if (!isUtc) {
// Note that we can't literally follow the ECMAScript spec (which this
// code is based on), because it leads to incorrect computations at
// the DST transition points.
//
// See V8's comment here:
// https://github.com/v8/v8/blob/089dd7d2447d6eaf57c8ba6d8f37957f3a269777/src/date.h#L118
// We need to remove the local timezone adjustment before asking for the
// correct zone offset.
int adjustment =
_localTimeZoneAdjustmentInSeconds() * Duration.microsecondsPerSecond;
// 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.
// We remove one hour to ensure that we have the correct offset at
// DST transitioning points. This is a temporary solution and only
// correct in timezones that shift for exactly one hour.
adjustment += Duration.microsecondsPerHour;
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.microsecondsPerSecond;
// 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() >
_maxMillisecondsSinceEpoch * Duration.microsecondsPerMillisecond) {
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.secondsPerDay;
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.microsecondsPerSecond;
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.microsecondsPerSecond);
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.secondsPerDay;
}
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);
}
}