/* * Copyright (c) 2024, Tim Flynn * * SPDX-License-Identifier: BSD-2-Clause */ #include #include #include namespace JS::Temporal { // https://tc39.es/proposal-temporal/#eqn-mathematicaldaysinyear u16 mathematical_days_in_year(i32 year) { // MathematicalDaysInYear(y) // = 365 if ((y) modulo 4) ≠ 0 // = 366 if ((y) modulo 4) = 0 and ((y) modulo 100) ≠ 0 // = 365 if ((y) modulo 100) = 0 and ((y) modulo 400) ≠ 0 // = 366 if ((y) modulo 400) = 0 if (modulo(year, 4) != 0) return 365; if (modulo(year, 4) == 0 && modulo(year, 100) != 0) return 366; if (modulo(year, 100) == 0 && modulo(year, 400) != 0) return 365; if (modulo(year, 400) == 0) return 366; VERIFY_NOT_REACHED(); } // https://tc39.es/proposal-temporal/#eqn-mathematicalinleapyear u8 mathematical_in_leap_year(double time) { // MathematicalInLeapYear(t) // = 0 if MathematicalDaysInYear(EpochTimeToEpochYear(t)) = 365 // = 1 if MathematicalDaysInYear(EpochTimeToEpochYear(t)) = 366 auto days_in_year = mathematical_days_in_year(epoch_time_to_epoch_year(time)); if (days_in_year == 365) return 0; if (days_in_year == 366) return 1; VERIFY_NOT_REACHED(); } // https://tc39.es/proposal-temporal/#eqn-EpochTimeToDayNumber double epoch_time_to_day_number(double time) { // EpochTimeToDayNumber(t) = floor(t / ℝ(msPerDay)) return floor(time / JS::ms_per_day); } // https://tc39.es/proposal-temporal/#eqn-epochdaynumberforyear double epoch_day_number_for_year(double year) { // EpochDayNumberForYear(y) = 365 × (y - 1970) + floor((y - 1969) / 4) - floor((y - 1901) / 100) + floor((y - 1601) / 400) return 365.0 * (year - 1970.0) + floor((year - 1969.0) / 4.0) - floor((year - 1901.0) / 100.0) + floor((year - 1601.0) / 400.0); } // https://tc39.es/proposal-temporal/#eqn-epochtimeforyear double epoch_time_for_year(double year) { // EpochTimeForYear(y) = ℝ(msPerDay) × EpochDayNumberForYear(y) return ms_per_day * epoch_day_number_for_year(year); } // https://tc39.es/proposal-temporal/#eqn-epochtimetoepochyear i32 epoch_time_to_epoch_year(double time) { // EpochTimeToEpochYear(t) = the largest integral Number y (closest to +∞) such that EpochTimeForYear(y) ≤ t return JS::year_from_time(time); } // https://tc39.es/proposal-temporal/#eqn-epochtimetodayinyear u16 epoch_time_to_day_in_year(double time) { // EpochTimeToDayInYear(t) = EpochTimeToDayNumber(t) - EpochDayNumberForYear(EpochTimeToEpochYear(t)) return static_cast(epoch_time_to_day_number(time) - epoch_day_number_for_year(epoch_time_to_epoch_year(time))); } // https://tc39.es/proposal-temporal/#eqn-epochtimetomonthinyear u8 epoch_time_to_month_in_year(double time) { auto day_in_year = epoch_time_to_day_in_year(time); auto in_leap_year = mathematical_in_leap_year(time); // EpochTimeToMonthInYear(t) // = 0 if 0 ≤ EpochTimeToDayInYear(t) < 31 // = 1 if 31 ≤ EpochTimeToDayInYear(t) < 59 + MathematicalInLeapYear(t) // = 2 if 59 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 90 + MathematicalInLeapYear(t) // = 3 if 90 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 120 + MathematicalInLeapYear(t) // = 4 if 120 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 151 + MathematicalInLeapYear(t) // = 5 if 151 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 181 + MathematicalInLeapYear(t) // = 6 if 181 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 212 + MathematicalInLeapYear(t) // = 7 if 212 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 243 + MathematicalInLeapYear(t) // = 8 if 243 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 273 + MathematicalInLeapYear(t) // = 9 if 273 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 304 + MathematicalInLeapYear(t) // = 10 if 304 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 334 + MathematicalInLeapYear(t) // = 11 if 334 + MathematicalInLeapYear(t) ≤ EpochTimeToDayInYear(t) < 365 + MathematicalInLeapYear(t) if (day_in_year < 31) return 0; if (day_in_year >= 31 && day_in_year < 59 + in_leap_year) return 1; if (day_in_year >= 59 + in_leap_year && day_in_year < 90 + in_leap_year) return 2; if (day_in_year >= 90 + in_leap_year && day_in_year < 120 + in_leap_year) return 3; if (day_in_year >= 120 + in_leap_year && day_in_year < 151 + in_leap_year) return 4; if (day_in_year >= 151 + in_leap_year && day_in_year < 181 + in_leap_year) return 5; if (day_in_year >= 181 + in_leap_year && day_in_year < 212 + in_leap_year) return 6; if (day_in_year >= 212 + in_leap_year && day_in_year < 243 + in_leap_year) return 7; if (day_in_year >= 243 + in_leap_year && day_in_year < 273 + in_leap_year) return 8; if (day_in_year >= 273 + in_leap_year && day_in_year < 304 + in_leap_year) return 9; if (day_in_year >= 304 + in_leap_year && day_in_year < 334 + in_leap_year) return 10; if (day_in_year >= 334 + in_leap_year && day_in_year < 365 + in_leap_year) return 11; VERIFY_NOT_REACHED(); } // https://tc39.es/proposal-temporal/#eqn-epochtimetoweekday u8 epoch_time_to_week_day(double time) { // EpochTimeToWeekDay(t) = (EpochTimeToDayNumber(t) + 4) modulo 7 return static_cast(modulo(epoch_time_to_day_number(time) + 4, 7.0)); } // https://tc39.es/proposal-temporal/#eqn-epochtimetodate u8 epoch_time_to_date(double time) { auto day_in_year = epoch_time_to_day_in_year(time); auto month_in_year = epoch_time_to_month_in_year(time); auto in_leap_year = mathematical_in_leap_year(time); // EpochTimeToDate(t) // = EpochTimeToDayInYear(t) + 1 if EpochTimeToMonthInYear(t) = 0 // = EpochTimeToDayInYear(t) - 30 if EpochTimeToMonthInYear(t) = 1 // = EpochTimeToDayInYear(t) - 58 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 2 // = EpochTimeToDayInYear(t) - 89 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 3 // = EpochTimeToDayInYear(t) - 119 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 4 // = EpochTimeToDayInYear(t) - 150 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 5 // = EpochTimeToDayInYear(t) - 180 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 6 // = EpochTimeToDayInYear(t) - 211 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 7 // = EpochTimeToDayInYear(t) - 242 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 8 // = EpochTimeToDayInYear(t) - 272 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 9 // = EpochTimeToDayInYear(t) - 303 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 10 // = EpochTimeToDayInYear(t) - 333 - MathematicalInLeapYear(t) if EpochTimeToMonthInYear(t) = 11 if (month_in_year == 0) return day_in_year + 1; if (month_in_year == 1) return day_in_year - 30; if (month_in_year == 2) return day_in_year - 58 - in_leap_year; if (month_in_year == 3) return day_in_year - 89 - in_leap_year; if (month_in_year == 4) return day_in_year - 119 - in_leap_year; if (month_in_year == 5) return day_in_year - 150 - in_leap_year; if (month_in_year == 6) return day_in_year - 180 - in_leap_year; if (month_in_year == 7) return day_in_year - 211 - in_leap_year; if (month_in_year == 8) return day_in_year - 242 - in_leap_year; if (month_in_year == 9) return day_in_year - 272 - in_leap_year; if (month_in_year == 10) return day_in_year - 303 - in_leap_year; if (month_in_year == 11) return day_in_year - 333 - in_leap_year; VERIFY_NOT_REACHED(); } }