time: Time.add (#7262)

vlib/time/time.v

@@ -171,15 +171,22 @@ pub fn (t Time) unix_time_milli() u64 {
 	return t.unix * 1000 + u64(t.microsecond / 1000)
 }
 
+// add returns a new time that duration is added
+pub fn (t Time) add(d Duration) Time {
+	microseconds := i64(t.unix) * 1000 * 1000 + t.microsecond + d.microseconds()
+	unix := microseconds / (1000 * 1000)
+	micro := microseconds % (1000 * 1000)
+	return unix2(int(unix), int(micro))
+}
+
 // add_seconds returns a new time struct with an added number of seconds.
 pub fn (t Time) add_seconds(seconds int) Time {
-	// TODO Add(d time.Duration)
-	return unix(int(t.unix + u64(seconds)))
+	return t.add(seconds * second)
 }
 
 // add_days returns a new time struct with an added number of days.
 pub fn (t Time) add_days(days int) Time {
-	return unix(int(t.unix + u64(i64(days) * 3600 * 24)))
+	return t.add(days * 24 * hour)
 }
 
 // since returns a number of seconds elapsed since a given time.

vlib/time/time_test.v

@@ -153,6 +153,21 @@ fn test_weekday_str() {
 	}
 }
 
+fn test_add() {
+	d_seconds := 3
+	d_microseconds := 13
+	duration := time.Duration(d_seconds * time.second + d_microseconds * time.microsecond)
+	t1 := time_to_test
+	t2 := time_to_test.add(duration)
+	assert t2.second == t1.second + d_seconds
+	assert t2.microsecond == t1.microsecond + d_microseconds
+	assert t2.unix == t1.unix + u64(d_seconds)
+	t3 := time_to_test.add(-duration)
+	assert t3.second == t1.second - d_seconds
+	assert t3.microsecond == t1.microsecond - d_microseconds
+	assert t3.unix == t1.unix - u64(d_seconds)
+}
+
 fn test_add_days() {
 	num_of_days := 3
 	t := time_to_test.add_days(num_of_days)