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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 // Dart core library. | |
| 5 | |
| 6 // VM implementation of DateImplementation. | |
| 7 patch class DateImplementation { | |
| 8 /* patch */ DateImplementation(int years, | |
| 9 [int month = 1, | |
| 10 int day = 1, | |
| 11 int hour = 0, | |
| 12 int minute = 0, | |
| 13 int second = 0, | |
| 14 int millisecond = 0, | |
| 15 bool isUtc = false]) | |
| 16 : this.isUtc = isUtc, | |
| 17 this.millisecondsSinceEpoch = _brokenDownDateToMillisecondsSinceEpoch( | |
| 18 years, month, day, hour, minute, second, millisecond, isUtc) { | |
| 19 if (millisecondsSinceEpoch === null) throw new IllegalArgumentException(); | |
| 20 if (isUtc === null) throw new IllegalArgumentException(); | |
| 21 } | |
| 22 | |
| 23 /* patch */ DateImplementation.now() | |
| 24 : isUtc = false, | |
| 25 millisecondsSinceEpoch = _getCurrentMs() { | |
| 26 } | |
| 27 | |
| 28 /* patch */ String get timeZoneName() { | |
| 29 if (isUtc) return "UTC"; | |
| 30 return _timeZoneName(millisecondsSinceEpoch); | |
| 31 } | |
| 32 | |
| 33 /* patch */ Duration get timeZoneOffset() { | |
| 34 if (isUtc) return new Duration(0); | |
| 35 int offsetInSeconds = _timeZoneOffsetInSeconds(millisecondsSinceEpoch); | |
| 36 return new Duration(seconds: offsetInSeconds); | |
| 37 } | |
| 38 | |
| 39 /* patch */ int get year() => _decomposeIntoYearMonthDay(_localDateInUtcMs)[0]
; | |
| 40 | |
| 41 /* patch */ int get month() => _decomposeIntoYearMonthDay(_localDateInUtcMs)[1
]; | |
| 42 | |
| 43 /* patch */ int get day() => _decomposeIntoYearMonthDay(_localDateInUtcMs)[2]; | |
| 44 | |
| 45 /* patch */ int get hour() { | |
| 46 int valueInHours = _flooredDivision(_localDateInUtcMs, | |
| 47 Duration.MILLISECONDS_PER_HOUR); | |
| 48 return valueInHours % Duration.HOURS_PER_DAY; | |
| 49 } | |
| 50 | |
| 51 /* patch */ int get minute() { | |
| 52 int valueInMinutes = _flooredDivision(_localDateInUtcMs, | |
| 53 Duration.MILLISECONDS_PER_MINUTE); | |
| 54 return valueInMinutes % Duration.MINUTES_PER_HOUR; | |
| 55 } | |
| 56 | |
| 57 /* patch */ int get second() { | |
| 58 // Seconds are unaffected by the timezone the user is in. So we can | |
| 59 // directly use the millisecondsSinceEpoch and not [_localDateInUtcMs]. | |
| 60 int valueInSeconds = | |
| 61 _flooredDivision(millisecondsSinceEpoch, | |
| 62 Duration.MILLISECONDS_PER_SECOND); | |
| 63 return valueInSeconds % Duration.SECONDS_PER_MINUTE; | |
| 64 } | |
| 65 | |
| 66 /* patch */ int get millisecond() { | |
| 67 // Milliseconds are unaffected by the timezone the user is in. So we can | |
| 68 // directly use the value and not the [_localDateInUtcValue]. | |
| 69 return millisecondsSinceEpoch % Duration.MILLISECONDS_PER_SECOND; | |
| 70 } | |
| 71 | |
| 72 /** Returns the weekday of [this]. In accordance with ISO 8601 a week | |
| 73 * starts with Monday. Monday has the value 1 up to Sunday with 7. */ | |
| 74 /* patch */ int get weekday() { | |
| 75 int daysSince1970 = | |
| 76 _flooredDivision(_localDateInUtcMs, Duration.MILLISECONDS_PER_DAY); | |
| 77 // 1970-1-1 was a Thursday. | |
| 78 return ((daysSince1970 + Date.THU - Date.MON) % Date.DAYS_IN_WEEK) + | |
| 79 Date.MON; | |
| 80 } | |
| 81 | |
| 82 | |
| 83 /** The first list contains the days until each month in non-leap years. The | |
| 84 * second list contains the days in leap years. */ | |
| 85 static final List<List<int>> _DAYS_UNTIL_MONTH = | |
| 86 const [const [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334], | |
| 87 const [0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335]]; | |
| 88 | |
| 89 // Returns the UTC year, month and day for the corresponding | |
| 90 // [millisecondsSinceEpoch]. | |
| 91 // Code is adapted from V8. | |
| 92 static List<int> _decomposeIntoYearMonthDay(int millisecondsSinceEpoch) { | |
| 93 // TODO(floitsch): cache result. | |
| 94 final int DAYS_IN_4_YEARS = 4 * 365 + 1; | |
| 95 final int DAYS_IN_100_YEARS = 25 * DAYS_IN_4_YEARS - 1; | |
| 96 final int DAYS_IN_400_YEARS = 4 * DAYS_IN_100_YEARS + 1; | |
| 97 final int DAYS_1970_TO_2000 = 30 * 365 + 7; | |
| 98 final int DAYS_OFFSET = 1000 * DAYS_IN_400_YEARS + 5 * DAYS_IN_400_YEARS - | |
| 99 DAYS_1970_TO_2000; | |
| 100 final int YEARS_OFFSET = 400000; | |
| 101 | |
| 102 int resultYear = 0; | |
| 103 int resultMonth = 0; | |
| 104 int resultDay = 0; | |
| 105 | |
| 106 // Always round down. | |
| 107 int days = _flooredDivision(millisecondsSinceEpoch, | |
| 108 Duration.MILLISECONDS_PER_DAY); | |
| 109 days += DAYS_OFFSET; | |
| 110 resultYear = 400 * (days ~/ DAYS_IN_400_YEARS) - YEARS_OFFSET; | |
| 111 days = days.remainder(DAYS_IN_400_YEARS); | |
| 112 days--; | |
| 113 int yd1 = days ~/ DAYS_IN_100_YEARS; | |
| 114 days = days.remainder(DAYS_IN_100_YEARS); | |
| 115 resultYear += 100 * yd1; | |
| 116 days++; | |
| 117 int yd2 = days ~/ DAYS_IN_4_YEARS; | |
| 118 days = days.remainder(DAYS_IN_4_YEARS); | |
| 119 resultYear += 4 * yd2; | |
| 120 days--; | |
| 121 int yd3 = days ~/ 365; | |
| 122 days = days.remainder(365); | |
| 123 resultYear += yd3; | |
| 124 | |
| 125 bool isLeap = (yd1 == 0 || yd2 != 0) && yd3 == 0; | |
| 126 if (isLeap) days++; | |
| 127 | |
| 128 List<int> daysUntilMonth = _DAYS_UNTIL_MONTH[isLeap ? 1 : 0]; | |
| 129 for (resultMonth = 12; | |
| 130 daysUntilMonth[resultMonth - 1] > days; | |
| 131 resultMonth--) { | |
| 132 // Do nothing. | |
| 133 } | |
| 134 resultDay = days - daysUntilMonth[resultMonth - 1] + 1; | |
| 135 return <int>[resultYear, resultMonth, resultDay]; | |
| 136 } | |
| 137 | |
| 138 /** | |
| 139 * Returns the amount of milliseconds in UTC that represent the same values | |
| 140 * as [this]. | |
| 141 * | |
| 142 * Say [:t:] is the result of this function, then | |
| 143 * * [:this.year == new Date.fromMillisecondsSinceEpoch(t, true).year:], | |
| 144 * * [:this.month == new Date.fromMillisecondsSinceEpoch(t, true).month:], | |
| 145 * * [:this.day == new Date.fromMillisecondsSinceEpoch(t, true).day:], | |
| 146 * * [:this.hour == new Date.fromMillisecondsSinceEpoch(t, true).hour:], | |
| 147 * * ... | |
| 148 * | |
| 149 * Daylight savings is computed as if the date was computed in [1970..2037]. | |
| 150 * If [this] lies outside this range then it is a year with similar | |
| 151 * properties (leap year, weekdays) is used instead. | |
| 152 */ | |
| 153 int get _localDateInUtcMs() { | |
| 154 int ms = millisecondsSinceEpoch; | |
| 155 if (isUtc) return ms; | |
| 156 int offset = | |
| 157 _timeZoneOffsetInSeconds(ms) * Duration.MILLISECONDS_PER_SECOND; | |
| 158 return ms + offset; | |
| 159 } | |
| 160 | |
| 161 static int _flooredDivision(int a, int b) { | |
| 162 return (a - (a < 0 ? b - 1 : 0)) ~/ b; | |
| 163 } | |
| 164 | |
| 165 // Returns the days since 1970 for the start of the given [year]. | |
| 166 // [year] may be before epoch. | |
| 167 static int _dayFromYear(int year) { | |
| 168 return 365 * (year - 1970) | |
| 169 + _flooredDivision(year - 1969, 4) | |
| 170 - _flooredDivision(year - 1901, 100) | |
| 171 + _flooredDivision(year - 1601, 400); | |
| 172 } | |
| 173 | |
| 174 static bool _isLeapYear(y) { | |
| 175 return (y.remainder(4) == 0) && | |
| 176 ((y.remainder(100) != 0) || (y.remainder(400) == 0)); | |
| 177 } | |
| 178 | |
| 179 static _brokenDownDateToMillisecondsSinceEpoch( | |
| 180 int years, int month, int day, | |
| 181 int hour, int minute, int second, int millisecond, | |
| 182 bool isUtc) { | |
| 183 if ((month < 1) || (month > 12)) return null; | |
| 184 if ((day < 1) || (day > 31)) return null; | |
| 185 // Leap seconds can lead to hour == 24. | |
| 186 if ((hour < 0) || (hour > 24)) return null; | |
| 187 if ((hour == 24) && ((minute != 0) || (second != 0))) return null; | |
| 188 if ((minute < 0) || (minute > 59)) return null; | |
| 189 if ((second < 0) || (second > 59)) return null; | |
| 190 if ((millisecond < 0) || (millisecond > 999)) return null; | |
| 191 | |
| 192 // First compute the seconds in UTC, independent of the [isUtc] flag. If | |
| 193 // necessary we will add the time-zone offset later on. | |
| 194 int days = day - 1; | |
| 195 days += _DAYS_UNTIL_MONTH[_isLeapYear(years) ? 1 : 0][month - 1]; | |
| 196 days += _dayFromYear(years); | |
| 197 int millisecondsSinceEpoch = days * Duration.MILLISECONDS_PER_DAY + | |
| 198 hour * Duration.MILLISECONDS_PER_HOUR + | |
| 199 minute * Duration.MILLISECONDS_PER_MINUTE+ | |
| 200 second * Duration.MILLISECONDS_PER_SECOND + | |
| 201 millisecond; | |
| 202 | |
| 203 // Since [_timeZoneOffsetInSeconds] will crash if the input is far out of | |
| 204 // the valid range we do a preliminary test that weeds out values that can | |
| 205 // not become valid even with timezone adjustments. | |
| 206 // The timezone adjustment is always less than a day, so adding a security | |
| 207 // margin of one day should be enough. | |
| 208 if (millisecondsSinceEpoch.abs() > | |
| 209 (_MAX_MILLISECONDS_SINCE_EPOCH + Duration.MILLISECONDS_PER_DAY)) { | |
| 210 return null; | |
| 211 } | |
| 212 | |
| 213 if (!isUtc) { | |
| 214 // Note that we need to remove the local timezone adjustement before | |
| 215 // asking for the correct zone offset. | |
| 216 int adjustment = _localTimeZoneAdjustmentInSeconds() * | |
| 217 Duration.MILLISECONDS_PER_SECOND; | |
| 218 int zoneOffset = | |
| 219 _timeZoneOffsetInSeconds(millisecondsSinceEpoch - adjustment); | |
| 220 millisecondsSinceEpoch -= zoneOffset * Duration.MILLISECONDS_PER_SECOND; | |
| 221 } | |
| 222 if (millisecondsSinceEpoch.abs() > _MAX_MILLISECONDS_SINCE_EPOCH) { | |
| 223 return null; | |
| 224 } | |
| 225 return millisecondsSinceEpoch; | |
| 226 } | |
| 227 | |
| 228 static int _weekDay(y) { | |
| 229 // 1/1/1970 was a Thursday. | |
| 230 return (_dayFromYear(y) + 4) % 7; | |
| 231 } | |
| 232 | |
| 233 /** | |
| 234 * Returns a year in the range 2008-2035 matching | |
| 235 * * leap year, and | |
| 236 * * week day of first day. | |
| 237 * | |
| 238 * Leap seconds are ignored. | |
| 239 * Adapted from V8's date implementation. See ECMA 262 - 15.9.1.9. | |
| 240 */ | |
| 241 static _equivalentYear(int year) { | |
| 242 // Returns the week day (in range 0 - 6). | |
| 243 // 1/1/1956 was a Sunday (i.e. weekday 0). 1956 was a leap-year. | |
| 244 // 1/1/1967 was a Sunday (i.e. weekday 0). | |
| 245 // Without leap years a subsequent year has a week day + 1 (for example | |
| 246 // 1/1/1968 was a Monday). With leap-years it jumps over one week day | |
| 247 // (e.g. 1/1/1957 was a Tuesday). | |
| 248 // After 12 years the weekdays have advanced by 12 days + 3 leap days = | |
| 249 // 15 days. 15 % 7 = 1. So after 12 years the week day has always | |
| 250 // (now independently of leap-years) advanced by one. | |
| 251 // weekDay * 12 gives thus a year starting with the wanted weekDay. | |
| 252 int recentYear = (_isLeapYear(year) ? 1956 : 1967) + (_weekDay(year) * 12); | |
| 253 // Close to the year 2008 the calendar cycles every 4 * 7 years (4 for the | |
| 254 // leap years, 7 for the weekdays). | |
| 255 // Find the year in the range 2008..2037 that is equivalent mod 28. | |
| 256 return 2008 + (recentYear - 2008) % 28; | |
| 257 } | |
| 258 | |
| 259 /** | |
| 260 * Returns the UTC year for the corresponding [secondsSinceEpoch]. | |
| 261 * It is relatively fast for values in the range 0 to year 2098. | |
| 262 * | |
| 263 * Code is adapted from V8. | |
| 264 */ | |
| 265 static int _yearsFromSecondsSinceEpoch(int secondsSinceEpoch) { | |
| 266 final int DAYS_IN_4_YEARS = 4 * 365 + 1; | |
| 267 final int DAYS_IN_100_YEARS = 25 * DAYS_IN_4_YEARS - 1; | |
| 268 final int DAYS_YEAR_2098 = DAYS_IN_100_YEARS + 6 * DAYS_IN_4_YEARS; | |
| 269 | |
| 270 int days = secondsSinceEpoch ~/ Duration.SECONDS_PER_DAY; | |
| 271 if (days > 0 && days < DAYS_YEAR_2098) { | |
| 272 // According to V8 this fast case works for dates from 1970 to 2099. | |
| 273 return 1970 + (4 * days + 2) ~/ DAYS_IN_4_YEARS; | |
| 274 } | |
| 275 int ms = secondsSinceEpoch * Duration.MILLISECONDS_PER_SECOND; | |
| 276 return _decomposeIntoYearMonthDay(ms)[0]; | |
| 277 } | |
| 278 | |
| 279 /** | |
| 280 * Returns a date in seconds that is equivalent to the current date. An | |
| 281 * equivalent date has the same fields ([:month:], [:day:], etc.) as the | |
| 282 * [this], but the [:year:] is in the range [1970..2037]. | |
| 283 * | |
| 284 * * The time since the beginning of the year is the same. | |
| 285 * * If [this] is in a leap year then the returned seconds are in a leap | |
| 286 * year, too. | |
| 287 * * The week day of [this] is the same as the one for the returned date. | |
| 288 */ | |
| 289 static int _equivalentSeconds(int millisecondsSinceEpoch) { | |
| 290 final int CUT_OFF_SECONDS = 2100000000; | |
| 291 | |
| 292 int secondsSinceEpoch = _flooredDivision(millisecondsSinceEpoch, | |
| 293 Duration.MILLISECONDS_PER_SECOND); | |
| 294 | |
| 295 if (secondsSinceEpoch < 0 || secondsSinceEpoch >= CUT_OFF_SECONDS) { | |
| 296 int year = _yearsFromSecondsSinceEpoch(secondsSinceEpoch); | |
| 297 int days = _dayFromYear(year); | |
| 298 int equivalentYear = _equivalentYear(year); | |
| 299 int equivalentDays = _dayFromYear(equivalentYear); | |
| 300 int diffDays = equivalentDays - days; | |
| 301 secondsSinceEpoch += diffDays * Duration.SECONDS_PER_DAY; | |
| 302 } | |
| 303 return secondsSinceEpoch; | |
| 304 } | |
| 305 | |
| 306 static int _timeZoneOffsetInSeconds(int millisecondsSinceEpoch) { | |
| 307 int equivalentSeconds = _equivalentSeconds(millisecondsSinceEpoch); | |
| 308 return _timeZoneOffsetInSecondsForClampedSeconds(equivalentSeconds); | |
| 309 } | |
| 310 | |
| 311 static String _timeZoneName(int millisecondsSinceEpoch) { | |
| 312 int equivalentSeconds = _equivalentSeconds(millisecondsSinceEpoch); | |
| 313 return _timeZoneNameForClampedSeconds(equivalentSeconds); | |
| 314 } | |
| 315 | |
| 316 // Natives | |
| 317 static int _getCurrentMs() native "DateNatives_currentTimeMillis"; | |
| 318 | |
| 319 static String _timeZoneNameForClampedSeconds(int secondsSinceEpoch) | |
| 320 native "DateNatives_timeZoneName"; | |
| 321 | |
| 322 static int _timeZoneOffsetInSecondsForClampedSeconds(int secondsSinceEpoch) | |
| 323 native "DateNatives_timeZoneOffsetInSeconds"; | |
| 324 | |
| 325 static int _localTimeZoneAdjustmentInSeconds() | |
| 326 native "DateNatives_localTimeZoneAdjustmentInSeconds"; | |
| 327 } | |
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