AK+LibC+LibCore: Have fewer implementations of days_in_month

2 files changed, 13 insertions, 0 deletions

diff --git a/AK/Time.cpp b/AK/Time.cpp
index 63253f90b7..ea9e470dba 100644
--- a/AK/Time.cpp
+++ b/AK/Time.cpp
@@ -42,4 +42,13 @@ int day_of_year(int year, unsigned month, int day)
     return day_of_year;
 }
 
+int days_in_month(int year, unsigned month)
+{
+    ASSERT(month >= 1 && month <= 12);
+    if (month == 2)
+        return is_leap_year(year) ? 29 : 28;
+
+    bool is_long_month = (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12);
+    return is_long_month ? 31 : 30;
+}
 }
diff --git a/AK/Time.h b/AK/Time.h
index 612b92f691..9a87f3c389 100644
--- a/AK/Time.h
+++ b/AK/Time.h
@@ -35,6 +35,9 @@ namespace AK {
 // can be negative.
 int day_of_year(int year, unsigned month, int day);
 
+// Month starts at 1. Month must be >= 1 and <= 12.
+int days_in_month(int year, unsigned month);
+
 inline bool is_leap_year(int year)
 {
     return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
@@ -169,6 +172,7 @@ inline bool operator!=(const TimespecType& a, const TimespecType& b)
 }
 
 using AK::day_of_year;
+using AK::days_in_month;
 using AK::is_leap_year;
 using AK::timespec_add;
 using AK::timespec_add_timeval;