comm-central/third_party/rust/calendrical_calculations/src/hebrew.rs

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// This file is part of ICU4X.
//
// The contents of this file implement algorithms from Calendrical Calculations
// by Reingold & Dershowitz, Cambridge University Press, 4th edition (2018),
// which have been released as Lisp code at <https://github.com/EdReingold/calendar-code2/>
// under the Apache-2.0 license. Accordingly, this file is released under
// the Apache License, Version 2.0 which can be found at the calendrical_calculations
use crate::helpers::{final_func, i64_to_i32, next_u8};
use crate::rata_die::{Moment, RataDie};
#[allow(unused_imports)]
use core_maths::*;
pub(crate) const FIXED_HEBREW_EPOCH: RataDie =
crate::julian::fixed_from_julian_book_version(-3761, 10, 7);
/// Biblical Hebrew dates. The months are reckoned a bit strangely, with the new year occurring on
/// Tishri (as in the civil calendar) but the months being numbered in a different order
#[derive(Copy, Clone, Debug, Default, Hash, Eq, PartialEq, PartialOrd, Ord)]
#[allow(clippy::exhaustive_structs)]
pub struct BookHebrew {
/// The year
pub year: i32,
/// The month
pub month: u8,
/// The day
pub day: u8,
}
// The BookHebrew Months
/// The biblical month number used for the month of Nisan
pub const NISAN: u8 = 1;
/// The biblical month number used for the month of Iyyar
pub const IYYAR: u8 = 2;
/// The biblical month number used for the month of Sivan
pub const SIVAN: u8 = 3;
/// The biblical month number used for the month of Tammuz
pub const TAMMUZ: u8 = 4;
/// The biblical month number used for the month of Av
pub const AV: u8 = 5;
/// The biblical month number used for the month of Elul
pub const ELUL: u8 = 6;
/// The biblical month number used for the month of Tishri
pub const TISHRI: u8 = 7;
/// The biblical month number used for the month of Marheshvan
pub const MARHESHVAN: u8 = 8;
/// The biblical month number used for the month of Kislev
pub const KISLEV: u8 = 9;
/// The biblical month number used for the month of Tevet
pub const TEVET: u8 = 10;
/// The biblical month number used for the month of Shevat
pub const SHEVAT: u8 = 11;
/// The biblical month number used for the month of Adar (and Adar I)
pub const ADAR: u8 = 12;
/// The biblical month number used for the month of Adar II
pub const ADARII: u8 = 13;
// BIBLICAL HEBREW CALENDAR FUNCTIONS
impl BookHebrew {
/// The civil calendar has the same year and day numbering as the book one, but the months are numbered
/// differently
pub fn to_civil_date(self) -> (i32, u8, u8) {
let biblical_month = self.month;
let biblical_year = self.year;
let mut civil_month;
civil_month = (biblical_month + 6) % 12;
if civil_month == 0 {
civil_month = 12;
}
if Self::is_hebrew_leap_year(biblical_year) && biblical_month < TISHRI {
civil_month += 1;
}
(biblical_year, civil_month, self.day)
}
/// The civil calendar has the same year and day numbering as the book one, but the months are numbered
/// differently
pub fn from_civil_date(civil_year: i32, civil_month: u8, civil_day: u8) -> Self {
let mut biblical_month;
if civil_month <= 6 {
biblical_month = civil_month + 6; // months 1-6 correspond to biblical months 7-12
} else {
biblical_month = civil_month - 6; // months 7-12 correspond to biblical months 1-6
if Self::is_hebrew_leap_year(civil_year) {
biblical_month -= 1
}
if biblical_month == 0 {
// Special case for Adar II in a leap year
biblical_month = 13;
}
}
BookHebrew {
year: civil_year,
month: biblical_month,
day: civil_day,
}
}
// Moment of mean conjunction (New Moon) of h_month in BookHebrew
#[allow(dead_code)]
pub(crate) fn molad(book_year: i32, book_month: u8) -> Moment {
let y = if book_month < TISHRI {
book_year + 1
} else {
book_year
}; // Treat Nisan as start of year
let months_elapsed = (book_month as f64 - TISHRI as f64) // Months this year
+ ((235.0 * y as f64 - 234.0) / 19.0).floor(); // Months until New Year.
Moment::new(
FIXED_HEBREW_EPOCH.to_f64_date() - (876.0 / 25920.0)
+ months_elapsed * (29.0 + (1.0 / 2.0) + (793.0 / 25920.0)),
)
}
// ADAR = 12, ADARII = 13
#[allow(dead_code)]
fn last_month_of_book_hebrew_year(book_year: i32) -> u8 {
if Self::is_hebrew_leap_year(book_year) {
ADARII
} else {
ADAR
}
}
// Number of days elapsed from the (Sunday) noon prior to the epoch of the BookHebrew Calendar to the molad of Tishri of BookHebrew year (h_year) or one day later
fn book_hebrew_calendar_elapsed_days(book_year: i32) -> i32 {
let months_elapsed = ((235.0 * book_year as f64 - 234.0) / 19.0).floor() as i64;
let parts_elapsed = 12084 + 13753 * months_elapsed;
let days = 29 * months_elapsed + (parts_elapsed as f64 / 25920.0).floor() as i64;
if (3 * (days + 1)).rem_euclid(7) < 3 {
days as i32 + 1
} else {
days as i32
}
}
// Delays to start of BookHebrew year to keep ordinary year in range 353-356 and leap year in range 383-386
fn book_hebrew_year_length_correction(book_year: i32) -> u8 {
let ny0 = Self::book_hebrew_calendar_elapsed_days(book_year - 1);
let ny1 = Self::book_hebrew_calendar_elapsed_days(book_year);
let ny2 = Self::book_hebrew_calendar_elapsed_days(book_year + 1);
if (ny2 - ny1) == 356 {
2
} else if (ny1 - ny0) == 382 {
1
} else {
0
}
}
// Fixed date of BookHebrew new year
pub fn book_hebrew_new_year(book_year: i32) -> RataDie {
RataDie::new(
FIXED_HEBREW_EPOCH.to_i64_date()
+ Self::book_hebrew_calendar_elapsed_days(book_year) as i64
+ Self::book_hebrew_year_length_correction(book_year) as i64,
)
}
pub fn days_in_book_hebrew_year(book_year: i32) -> u16 {
(Self::book_hebrew_new_year(1 + book_year) - Self::book_hebrew_new_year(book_year)) as u16
}
pub fn is_hebrew_leap_year(book_year: i32) -> bool {
(7 * book_year + 1).rem_euclid(19) < 7
}
// True if the month Marheshvan is going to be long in given BookHebrew year
#[allow(dead_code)]
fn is_long_marheshvan(book_year: i32) -> bool {
let long_marheshavan_year_lengths = [355, 385];
long_marheshavan_year_lengths.contains(&Self::days_in_book_hebrew_year(book_year))
}
// True if the month Kislve is going to be short in given BookHebrew year
#[allow(dead_code)]
fn is_short_kislev(book_year: i32) -> bool {
let short_kislev_year_lengths = [353, 383];
short_kislev_year_lengths.contains(&Self::days_in_book_hebrew_year(book_year))
}
// Last day of month (h_month) in BookHebrew year (book_year)
pub fn last_day_of_book_hebrew_month(book_year: i32, book_month: u8) -> u8 {
match book_month {
IYYAR | TAMMUZ | ELUL | TEVET | ADARII => 29,
ADAR => {
if !Self::is_hebrew_leap_year(book_year) {
29
} else {
30
}
}
MARHESHVAN => {
if !Self::is_long_marheshvan(book_year) {
29
} else {
30
}
}
KISLEV => {
if Self::is_short_kislev(book_year) {
29
} else {
30
}
}
_ => 30,
}
}
pub fn fixed_from_book_hebrew(date: BookHebrew) -> RataDie {
let book_year = date.year;
let book_month = date.month;
let book_day = date.day;
let mut total_days = Self::book_hebrew_new_year(book_year) + book_day.into() - 1; // (day - 1) Days so far this month.
if book_month < TISHRI {
// Then add days in prior months this year before
for m in
(TISHRI..=Self::last_month_of_book_hebrew_year(book_year)).chain(NISAN..book_month)
{
total_days += Self::last_day_of_book_hebrew_month(book_year, m).into();
}
} else {
// Else add days in prior months this year
for m in TISHRI..book_month {
total_days += Self::last_day_of_book_hebrew_month(book_year, m).into();
}
}
total_days
}
pub fn book_hebrew_from_fixed(date: RataDie) -> BookHebrew {
let approx = i64_to_i32(
1 + ((date - FIXED_HEBREW_EPOCH) as f64).div_euclid(35975351.0 / 98496.0) as i64, // The value 35975351/98496, the average length of a BookHebrew year, can be approximated by 365.25
)
.unwrap_or_else(|e| e.saturate());
// Search forward for the year
let year_condition = |year: i32| Self::book_hebrew_new_year(year) <= date;
let year = final_func(approx - 1, year_condition);
// Starting month for search for month.
let start = if date
< Self::fixed_from_book_hebrew(BookHebrew {
year,
month: NISAN,
day: 1,
}) {
TISHRI
} else {
NISAN
};
let month_condition = |m: u8| {
date <= Self::fixed_from_book_hebrew(BookHebrew {
year,
month: m,
day: Self::last_day_of_book_hebrew_month(year, m),
})
};
// Search forward from either Tishri or Nisan.
let month = next_u8(start, month_condition);
// Calculate the day by subtraction.
let day = (date
- Self::fixed_from_book_hebrew(BookHebrew {
year,
month,
day: 1,
}))
+ 1;
BookHebrew {
year,
month,
day: day as u8,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[derive(Debug)]
struct DateCase {
year: i32,
month: u8,
day: u8,
}
static TEST_FIXED_DATE: [i64; 33] = [
-214193, -61387, 25469, 49217, 171307, 210155, 253427, 369740, 400085, 434355, 452605,
470160, 473837, 507850, 524156, 544676, 567118, 569477, 601716, 613424, 626596, 645554,
664224, 671401, 694799, 704424, 708842, 709409, 709580, 727274, 728714, 744313, 764652,
];
static HEBREW_DATES: [DateCase; 33] = [
DateCase {
year: 3174,
month: 5,
day: 10,
},
DateCase {
year: 3593,
month: 9,
day: 25,
},
DateCase {
year: 3831,
month: 7,
day: 3,
},
DateCase {
year: 3896,
month: 7,
day: 9,
},
DateCase {
year: 4230,
month: 10,
day: 18,
},
DateCase {
year: 4336,
month: 3,
day: 4,
},
DateCase {
year: 4455,
month: 8,
day: 13,
},
DateCase {
year: 4773,
month: 2,
day: 6,
},
DateCase {
year: 4856,
month: 2,
day: 23,
},
DateCase {
year: 4950,
month: 1,
day: 7,
},
DateCase {
year: 5000,
month: 13,
day: 8,
},
DateCase {
year: 5048,
month: 1,
day: 21,
},
DateCase {
year: 5058,
month: 2,
day: 7,
},
DateCase {
year: 5151,
month: 4,
day: 1,
},
DateCase {
year: 5196,
month: 11,
day: 7,
},
DateCase {
year: 5252,
month: 1,
day: 3,
},
DateCase {
year: 5314,
month: 7,
day: 1,
},
DateCase {
year: 5320,
month: 12,
day: 27,
},
DateCase {
year: 5408,
month: 3,
day: 20,
},
DateCase {
year: 5440,
month: 4,
day: 3,
},
DateCase {
year: 5476,
month: 5,
day: 5,
},
DateCase {
year: 5528,
month: 4,
day: 4,
},
DateCase {
year: 5579,
month: 5,
day: 11,
},
DateCase {
year: 5599,
month: 1,
day: 12,
},
DateCase {
year: 5663,
month: 1,
day: 22,
},
DateCase {
year: 5689,
month: 5,
day: 19,
},
DateCase {
year: 5702,
month: 7,
day: 8,
},
DateCase {
year: 5703,
month: 1,
day: 14,
},
DateCase {
year: 5704,
month: 7,
day: 8,
},
DateCase {
year: 5752,
month: 13,
day: 12,
},
DateCase {
year: 5756,
month: 12,
day: 5,
},
DateCase {
year: 5799,
month: 8,
day: 12,
},
DateCase {
year: 5854,
month: 5,
day: 5,
},
];
static EXPECTED_MOLAD_DATES: [f64; 33] = [
-1850718767f64 / 8640f64,
-1591805959f64 / 25920f64,
660097927f64 / 25920f64,
1275506059f64 / 25920f64,
4439806081f64 / 25920f64,
605235101f64 / 2880f64,
3284237627f64 / 12960f64,
9583515841f64 / 25920f64,
2592403883f64 / 6480f64,
2251656649f64 / 5184f64,
11731320839f64 / 25920f64,
12185988041f64 / 25920f64,
6140833583f64 / 12960f64,
6581722991f64 / 12960f64,
6792982499f64 / 12960f64,
4705980311f64 / 8640f64,
14699670013f64 / 25920f64,
738006961f64 / 1296f64,
1949499007f64 / 3240f64,
5299956319f64 / 8640f64,
3248250415f64 / 5184f64,
16732660061f64 / 25920f64,
17216413717f64 / 25920f64,
1087650871f64 / 1620f64,
2251079609f64 / 3240f64,
608605601f64 / 864f64,
306216383f64 / 432f64,
18387526207f64 / 25920f64,
3678423761f64 / 5184f64,
1570884431f64 / 2160f64,
18888119389f64 / 25920f64,
19292268013f64 / 25920f64,
660655045f64 / 864f64,
];
static EXPECTED_LAST_HEBREW_MONTH: [u8; 33] = [
12, 12, 12, 12, 12, 12, 12, 12, 13, 12, 13, 12, 12, 12, 12, 13, 12, 13, 12, 13, 12, 12, 12,
12, 12, 13, 12, 13, 12, 13, 12, 12, 12,
];
static EXPECTED_HEBREW_ELASPED_CALENDAR_DAYS: [i32; 33] = [
1158928, 1311957, 1398894, 1422636, 1544627, 1583342, 1626812, 1742956, 1773254, 1807597,
1825848, 1843388, 1847051, 1881010, 1897460, 1917895, 1940545, 1942729, 1974889, 1986554,
1999723, 2018712, 2037346, 2044640, 2068027, 2077507, 2082262, 2082617, 2083000, 2100511,
2101988, 2117699, 2137779,
];
static EXPECTED_FIXED_HEBREW_NEW_YEAR: [i64; 33] = [
-214497, -61470, 25467, 49209, 171200, 209915, 253385, 369529, 399827, 434172, 452421,
469963, 473624, 507583, 524033, 544468, 567118, 569302, 601462, 613127, 626296, 645285,
663919, 671213, 694600, 704080, 708835, 709190, 709573, 727084, 728561, 744272, 764352,
];
static EXPECTED_DAYS_IN_HEBREW_YEAR: [u16; 33] = [
354, 354, 355, 355, 355, 355, 355, 353, 383, 354, 383, 354, 354, 355, 353, 383, 353, 385,
353, 383, 355, 354, 354, 354, 355, 385, 355, 383, 354, 385, 355, 354, 355,
];
static EXPECTED_MARHESHVAN_VALUES: [bool; 33] = [
false, false, true, true, true, true, true, false, false, false, false, false, false, true,
false, false, false, true, false, false, true, false, false, false, true, true, true,
false, false, true, true, false, true,
];
static EXPECTED_KISLEV_VALUES: [bool; 33] = [
false, false, false, false, false, false, false, true, true, false, true, false, false,
false, true, true, true, false, true, true, false, false, false, false, false, false,
false, true, false, false, false, false, false,
];
static EXPECTED_DAY_IN_MONTH: [u8; 33] = [
30, 30, 30, 30, 29, 30, 30, 29, 29, 30, 29, 30, 29, 29, 30, 30, 30, 30, 30, 29, 30, 29, 30,
30, 30, 30, 30, 30, 30, 29, 29, 29, 30,
];
#[allow(dead_code)]
static CIVIL_EXPECTED_DAY_IN_MONTH: [u8; 33] = [
30, 30, 30, 30, 29, 30, 29, 29, 29, 30, 30, 30, 29, 29, 30, 29, 30, 29, 29, 30, 30, 29, 30,
30, 30, 30, 30, 29, 30, 30, 29, 29, 30,
];
#[test]
fn test_hebrew_epoch() {
// page 119 of the Calendrical Calculations book
let fixed_hebrew_date = -1373427.0;
assert_eq!(FIXED_HEBREW_EPOCH.to_f64_date(), fixed_hebrew_date);
}
#[test]
fn test_hebrew_molad() {
let precision = 1_00000f64;
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_MOLAD_DATES.iter()) {
let molad =
(BookHebrew::molad(case.year, case.month).inner() * precision).round() / precision;
let final_expected = (expected * precision).round() / precision;
assert_eq!(molad, final_expected, "{case:?}");
}
}
#[test]
fn test_last_book_hebrew_month() {
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_LAST_HEBREW_MONTH.iter()) {
let last_month = BookHebrew::last_month_of_book_hebrew_year(case.year);
assert_eq!(last_month, *expected);
}
}
#[test]
fn test_book_hebrew_calendar_elapsed_days() {
for (case, expected) in HEBREW_DATES
.iter()
.zip(EXPECTED_HEBREW_ELASPED_CALENDAR_DAYS.iter())
{
let elapsed_days = BookHebrew::book_hebrew_calendar_elapsed_days(case.year);
assert_eq!(elapsed_days, *expected);
}
}
#[test]
fn test_book_hebrew_year_length_correction() {
let year_length_correction: [u8; 33] = [
2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0,
];
for (case, expected) in HEBREW_DATES.iter().zip(year_length_correction.iter()) {
let correction = BookHebrew::book_hebrew_year_length_correction(case.year);
assert_eq!(correction, *expected);
}
}
#[test]
fn test_book_hebrew_new_year() {
for (case, expected) in HEBREW_DATES
.iter()
.zip(EXPECTED_FIXED_HEBREW_NEW_YEAR.iter())
{
let f_date = BookHebrew::book_hebrew_new_year(case.year);
assert_eq!(f_date.to_i64_date(), *expected);
}
}
#[test]
fn test_days_in_book_hebrew_year() {
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_DAYS_IN_HEBREW_YEAR.iter()) {
let days_in_year = BookHebrew::days_in_book_hebrew_year(case.year);
assert_eq!(days_in_year, *expected);
}
}
#[test]
fn test_long_marheshvan() {
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_MARHESHVAN_VALUES.iter()) {
let marsheshvan = BookHebrew::is_long_marheshvan(case.year);
assert_eq!(marsheshvan, *expected);
}
}
#[test]
fn test_short_kislev() {
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_KISLEV_VALUES.iter()) {
let kislev = BookHebrew::is_short_kislev(case.year);
assert_eq!(kislev, *expected);
}
}
#[test]
fn test_last_day_in_book_hebrew_month() {
for (case, expected) in HEBREW_DATES.iter().zip(EXPECTED_DAY_IN_MONTH.iter()) {
let days_in_month = BookHebrew::last_day_of_book_hebrew_month(case.year, case.month);
assert_eq!(days_in_month, *expected);
}
}
#[test]
fn test_fixed_from_book_hebrew() {
for (case, f_date) in HEBREW_DATES.iter().zip(TEST_FIXED_DATE.iter()) {
assert_eq!(
BookHebrew::fixed_from_book_hebrew(BookHebrew {
year: case.year,
month: case.month,
day: case.day
}),
RataDie::new(*f_date),
"{case:?}"
);
}
}
#[test]
fn test_book_hebrew_from_fixed() {
for (case, f_date) in HEBREW_DATES.iter().zip(TEST_FIXED_DATE.iter()) {
assert_eq!(
BookHebrew::book_hebrew_from_fixed(RataDie::new(*f_date)),
BookHebrew {
year: case.year,
month: case.month,
day: case.day
},
"{case:?}"
);
}
}
#[test]
fn test_civil_to_book_conversion() {
for (f_date, case) in TEST_FIXED_DATE.iter().zip(HEBREW_DATES.iter()) {
let book_hebrew = BookHebrew::book_hebrew_from_fixed(RataDie::new(*f_date));
let (y, m, d) = book_hebrew.to_civil_date();
let book_hebrew = BookHebrew::from_civil_date(y, m, d);
assert_eq!(
(case.year, case.month),
(book_hebrew.year, book_hebrew.month)
)
}
}
}