ADD day of year

Author: FatulM

lib/src/date.dart

@@ -52,6 +52,11 @@ abstract class Date implements Comparable<Date> {
   /// Milliseconds [0..999]
   int get millisecond;
 
+  /// day of year.
+  ///
+  /// calculated, not stored.
+  int get dayOfYear;
+
   /// Returns the time part as [Duration].
   Duration get time {
     return Duration(

lib/src/gregorian/gregorian_calculation.dart

@@ -172,4 +172,17 @@ class _Algo {
       millisecond,
     );
   }
+
+  /// get day of year
+  static int getDayOfYear(bool isLeap, int month, int day) {
+    // day accumulation in regular years:
+    const r = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365];
+    // day accumulation in leap years:
+    const l = [0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366];
+    if (isLeap) {
+      return l[month - 1] + day;
+    } else {
+      return r[month - 1] + day;
+    }
+  }
 }

lib/src/gregorian/gregorian_date.dart

@@ -75,6 +75,11 @@ class Gregorian extends Date {
   @override
   final int millisecond;
 
+  @override
+  int get dayOfYear {
+    return _Algo.getDayOfYear(isLeapYear(), month, day);
+  }
+
   /// Week day number
   /// [monday] = 1
   /// [sunday] = 7

lib/src/jalali/jalali_calculation.dart

@@ -268,6 +268,16 @@ class _Algo {
       isLeap,
     );
   }
+
+  /// get day of year
+  static int getDayOfYear(bool isLeap, int month, int day) {
+    // day accumulation in regular years:
+    const r = [0, 31, 62, 93, 124, 155, 186, 216, 246, 276, 306, 336, 365];
+    // day accumulation in leap years:
+    // no need, since the last day is the leap day.
+    // const l = [0, 31, 62, 93, 124, 155, 186, 216, 246, 276, 306, 336, 366];
+    return r[month - 1] + day;
+  }
 }
 
 /// Internal used for Jalali calculation

lib/src/jalali/jalali_date.dart

@@ -76,6 +76,11 @@ class Jalali extends Date {
   @override
   final int millisecond;
 
+  @override
+  int get dayOfYear {
+    return _Algo.getDayOfYear(isLeapYear(), month, day);
+  }
+
   /// Whether is leap year.
   ///
   /// It is cached since we always calculate it

test/shamsi_date_test.dart

@@ -1696,6 +1696,34 @@ void main() {
     expect(gdt.millisecond, 219);
   });
 
+  test('Jalali.dayOfYear', () {
+    expect(Jalali(1404).isLeapYear(), false);
+    expect(Jalali(1404, 1, 1).dayOfYear, 1);
+    expect(Jalali(1404, 12, 29).dayOfYear, 365);
+
+    expect(Jalali(1403).isLeapYear(), true);
+    expect(Jalali(1403, 1, 1).dayOfYear, 1);
+    expect(Jalali(1403, 12, 30).dayOfYear, 366);
+
+    expect(Jalali(1404, 2, 2).dayOfYear, 33);
+    expect(Jalali(1404, 4, 16).dayOfYear, 109);
+    expect(Jalali(1404, 12, 25).dayOfYear, 361);
+  });
+
+  test('Gregorian.dayOfYear', () {
+    expect(Gregorian(2025).isLeapYear(), false);
+    expect(Gregorian(2025, 1, 1).dayOfYear, 1);
+    expect(Gregorian(2025, 12, 31).dayOfYear, 365);
+
+    expect(Gregorian(2028).isLeapYear(), true);
+    expect(Gregorian(2028, 1, 1).dayOfYear, 1);
+    expect(Gregorian(2028, 12, 31).dayOfYear, 366);
+
+    expect(Gregorian(2025, 10, 31).dayOfYear, 304);
+    expect(Gregorian(2025, 4, 22).dayOfYear, 112);
+    expect(Gregorian(2028, 4, 22).dayOfYear, 113);
+  });
+
   test('Iranian Calendar Authority Test Cases', () {
     // Persian leap year data provided by the Iranian calendar authority at:
     // https://calendar.ut.ac.ir/Fa/News/Data/Doc/KabiseShamsi1206-1498-new.pdf