Add Match function

cronexpr.go

@@ -81,7 +81,7 @@ func Parse(cronLine string) (*Expression, error) {
 		fieldCount = 7
 	}
 
-	var expr = Expression{}
+	var expr = Expression{expression:cronLine}
 	var field = 0
 	var err error
 
@@ -264,3 +264,27 @@ func (expr *Expression) NextN(fromTime time.Time, n uint) []time.Time {
 	}
 	return nextTimes
 }
+
+func (expr *Expression) Matches(refTime time.Time) bool {
+	testSecondsAndYears := expr.testSeconds()
+	return (!testSecondsAndYears || containsVal(expr.secondList, refTime.Second())) &&
+		containsVal(expr.minuteList, refTime.Minute()) &&
+		containsVal(expr.hourList, refTime.Hour()) &&
+		expr.daysOfMonth[refTime.Day()] &&
+		containsVal(expr.monthList, int(refTime.Month())) &&
+		expr.daysOfWeek[int(refTime.Weekday())] &&
+		(!testSecondsAndYears || containsVal(expr.yearList, refTime.Year()))
+}
+
+func containsVal(sl []int, v int) bool {
+	for _, i := range sl {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+
+func (expr *Expression) testSeconds() bool {
+	return len(fieldFinder.FindAllStringIndex(expr.expression, -1)) > 6
+}

cronexpr_test.go

@@ -307,6 +307,44 @@ func TestInterval_Interval60Issue(t *testing.T){
 	}
 }
 
+func TestMatches(t *testing.T) {
+	var cases = []struct {
+		cronLine string
+		refTime string
+		shouldMatch bool
+	}{
+		// m h dom mon dow
+		{"5 * * * *", "2013-09-02 01:44:32", false}, // minutes
+		{"5 * * * *", "2013-09-02 01:05:32", true},
+		{"* 3 * * *", "2013-09-02 01:45:32", false}, // hours
+		{"* 3 * * *", "2013-09-02 03:45:32", true},
+		{"* * 2 * *", "2013-09-03 03:45:32", false}, // day of month
+		{"* * 2 * *", "2013-09-02 03:45:32", true},
+		{"* * * 8 *", "2013-09-03 03:45:32", false}, // month
+		{"* * * 9 *", "2013-09-03 03:45:32", true},
+		{"* * * * 5", "2018-03-01 03:45:32", false}, // day of week
+		{"* * * * 4", "2018-03-01 03:45:32", true},
+
+		// s m h dom mon dow year
+		{"0 * * * * * *", "2018-03-01 03:45:32", false}, // seconds
+		{"32 * * * * * *", "2018-03-01 03:45:32", true},
+		{"* * * * * * 2013", "2018-03-01 03:45:32", false}, // years
+		{"* * * * * * 2018", "2018-03-01 03:45:32", true},
+
+		{"32 */15 1/2 1 3 4 2018", "2018-03-01 03:45:32", true},
+	}
+
+	for i, c := range cases {
+		expression, _ := cronexpr.Parse(c.cronLine)
+		refTime, _ := time.Parse("2006-01-02 15:04:05", c.refTime)
+		matches := expression.Matches(refTime)
+		if matches != c.shouldMatch {
+			t.Errorf("Case %d: Parse(%q).Matches(T{%q}) returned '%t', expected '%t'", i+1, c.cronLine, c.refTime, matches, c.shouldMatch)
+		}
+	}
+}
+
+
 /******************************************************************************/
 
 var benchmarkExpressions = []string{