From 56f1db6dfa30ede8462ba61edb1ded2590d069d4 Mon Sep 17 00:00:00 2001
From: Jacob Pratt <jacob@jhpratt.dev>
Date: Fri, 25 Oct 2024 06:17:44 -0400
Subject: [PATCH] Add `Month::length`, `days_in_month`

---
 time/src/date.rs             | 10 +++++-----
 time/src/month.rs            | 17 ++++++++++++++++-
 time/src/offset_date_time.rs |  2 +-
 time/src/util.rs             | 22 +++++++++++++++-------
 4 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/time/src/date.rs b/time/src/date.rs
index 92c28114b..56253d9b6 100644
--- a/time/src/date.rs
+++ b/time/src/date.rs
@@ -24,7 +24,7 @@ use crate::internal_macros::{
 };
 #[cfg(feature = "parsing")]
 use crate::parsing::Parsable;
-use crate::util::{days_in_year, days_in_year_month, is_leap_year, weeks_in_year};
+use crate::util::{days_in_year, is_leap_year, weeks_in_year};
 use crate::{error, Duration, Month, PrimitiveDateTime, Time, Weekday};
 
 type Year = RangedI32<MIN_YEAR, MAX_YEAR>;
@@ -120,12 +120,12 @@ impl Date {
         ensure_ranged!(Year: year);
         match day {
             1..=28 => {}
-            29..=31 if day <= days_in_year_month(year, month) => {}
+            29..=31 if day <= month.length(year) => {}
             _ => {
                 return Err(error::ComponentRange {
                     name: "day",
                     minimum: 1,
-                    maximum: days_in_year_month(year, month) as _,
+                    maximum: month.length(year) as _,
                     value: day as _,
                     conditional_range: true,
                 });
@@ -1103,12 +1103,12 @@ impl Date {
     pub const fn replace_day(self, day: u8) -> Result<Self, error::ComponentRange> {
         match day {
             1..=28 => {}
-            29..=31 if day <= days_in_year_month(self.year(), self.month()) => {}
+            29..=31 if day <= self.month().length(self.year()) => {}
             _ => {
                 return Err(error::ComponentRange {
                     name: "day",
                     minimum: 1,
-                    maximum: days_in_year_month(self.year(), self.month()) as _,
+                    maximum: self.month().length(self.year()) as _,
                     value: day as _,
                     conditional_range: true,
                 });
diff --git a/time/src/month.rs b/time/src/month.rs
index 55e53b4b8..6a3d2fa14 100644
--- a/time/src/month.rs
+++ b/time/src/month.rs
@@ -7,7 +7,7 @@ use core::str::FromStr;
 use powerfmt::smart_display::{FormatterOptions, Metadata, SmartDisplay};
 
 use self::Month::*;
-use crate::error;
+use crate::{error, util};
 
 /// Months of the year.
 #[repr(u8)]
@@ -65,6 +65,21 @@ impl Month {
         }
     }
 
+    /// Get the number of days in the month of a given year.
+    ///
+    /// ```rust
+    /// # use time::Month;
+    /// assert_eq!(Month::February.length(2020), 29);
+    /// ```
+    pub const fn length(self, year: i32) -> u8 {
+        match self {
+            January | March | May | July | August | October | December => 31,
+            April | June | September | November => 30,
+            February if util::is_leap_year(year) => 29,
+            February => 28,
+        }
+    }
+
     /// Get the previous month.
     ///
     /// ```rust
diff --git a/time/src/offset_date_time.rs b/time/src/offset_date_time.rs
index 9b478a79c..3ae82cea7 100644
--- a/time/src/offset_date_time.rs
+++ b/time/src/offset_date_time.rs
@@ -1317,7 +1317,7 @@ impl OffsetDateTime {
         time.hour() == 23
             && time.minute() == 59
             && time.second() == 59
-            && date.day() == util::days_in_year_month(year, date.month())
+            && date.day() == date.month().length(year)
     }
 }
 
diff --git a/time/src/util.rs b/time/src/util.rs
index 622a23aac..6a0e9e430 100644
--- a/time/src/util.rs
+++ b/time/src/util.rs
@@ -14,20 +14,28 @@ pub(crate) enum DateAdjustment {
     None,
 }
 
+/// Get the number of days in the month of a given year.
+///
+/// ```rust
+/// # use time::{Month, util};
+/// assert_eq!(util::days_in_month(Month::February, 2020), 29);
+/// ```
+pub const fn days_in_month(month: Month, year: i32) -> u8 {
+    month.length(year)
+}
+
 /// Get the number of days in the month of a given year.
 ///
 /// ```rust
 /// # use time::{Month, util};
 /// assert_eq!(util::days_in_year_month(2020, Month::February), 29);
 /// ```
+#[deprecated(
+    since = "0.3.37",
+    note = "use `days_in_month` or `Month::length` instead"
+)]
 pub const fn days_in_year_month(year: i32, month: Month) -> u8 {
-    use Month::*;
-    match month {
-        January | March | May | July | August | October | December => 31,
-        April | June | September | November => 30,
-        February if is_leap_year(year) => 29,
-        February => 28,
-    }
+    month.length(year)
 }
 
 /// Update time zone information from the system.