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[datetime]: Remove the definition of EPOCH

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flysand7
2025-03-06 20:20:05 +11:00
parent 7d26edb83c
commit 47eefb3f21
2 changed files with 9 additions and 12 deletions
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6
core/time/datetime/constants.odin
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@@ -5,13 +5,11 @@ Type representing a mononotic day number corresponding to a date.
Ordinal 1 = Midnight Monday, January 1, 1 A.D. (Gregorian)
| Midnight Monday, January 3, 1 A.D. (Julian)
Every other ordinal counts days forwards, starting from the above date.
*/
Ordinal :: i64
/*
*/
EPOCH :: Ordinal(1)
/*
Minimum valid value for date.

15
core/time/datetime/datetime.odin
View File

@@ -98,7 +98,7 @@ This procedure takes the value of an ordinal and returns the day of week for
that ordinal.
*/
day_of_week :: proc "contextless" (ordinal: Ordinal) -> (day: Weekday) {
return Weekday((ordinal - EPOCH + 1) %% 7)
return Weekday(ordinal %% 7)
}
/*
@@ -349,8 +349,7 @@ the result is unspecified.
unsafe_date_to_ordinal :: proc "contextless" (date: Date) -> (ordinal: Ordinal) {
year_minus_one := date.year - 1
// Day before epoch
ordinal = EPOCH - 1
ordinal = 0
// Add non-leap days
ordinal += 365 * year_minus_one
@@ -382,17 +381,17 @@ This procedure returns the year and the day of the year of a given ordinal.
Of the ordinal is outside of its valid range, the result is unspecified.
*/
unsafe_ordinal_to_year :: proc "contextless" (ordinal: Ordinal) -> (year: i64, day_ordinal: i64) {
// Days after epoch
d0 := ordinal - EPOCH
// Correct for leap year cycle starting at day 1.
d0 := ordinal - 1
// Number of 400-year cycles and remainder
n400, d1 := divmod(d0, 146097)
n400, d1 := divmod(d0, 365*400 + 100 - 3)
// Number of 100-year cycles and remainder
n100, d2 := divmod(d1, 36524)
n100, d2 := divmod(d1, 365*100 + 25 - 1)
// Number of 4-year cycles and remainder
n4, d3 := divmod(d2, 1461)
n4, d3 := divmod(d2, 365*4 + 1)
// Number of remaining days
n1, d4 := divmod(d3, 365)