Do not divide then multiply as it may result in incorrect result (#37)

For example, DurationValue("4236579305ms", ...) will return 4236579304, because
the result of diving 4236579305 by 1000 and then multiplying the result by 1000
will be 4.2365793049999995e+09, which when converted to int64 will result in
incorrect value.

Signed-off-by: Artem Fetishev <[email protected]>

lexer.go

@@ -575,25 +575,25 @@ func parseSingleDuration(s string, step int64) (float64, error) {
 	var mp float64
 	switch s[len(numPart):] {
 	case "ms":
-		mp = 1e-3
-	case "s":
 		mp = 1
+	case "s":
+		mp = 1000
 	case "m":
-		mp = 60
+		mp = 60 * 1000
 	case "h":
-		mp = 60 * 60
+		mp = 60 * 60 * 1000
 	case "d":
-		mp = 24 * 60 * 60
+		mp = 24 * 60 * 60 * 1000
 	case "w":
-		mp = 7 * 24 * 60 * 60
+		mp = 7 * 24 * 60 * 60 * 1000
 	case "y":
-		mp = 365 * 24 * 60 * 60
+		mp = 365 * 24 * 60 * 60 * 1000
 	case "i":
-		mp = float64(step) / 1e3
+		mp = float64(step)
 	default:
 		return 0, fmt.Errorf("invalid duration suffix in %q", s)
 	}
-	return mp * f * 1e3, nil
+	return mp * f, nil
 }
 
 // scanDuration scans duration, which must start with positive num.

lexer_test.go

@@ -595,6 +595,7 @@ func TestDurationSuccess(t *testing.T) {
 	// Integer durations
 	f("123ms", 42, 123)
 	f("-123ms", 42, -123)
+	f("4236579305ms", 42, 4236579305)
 	f("123s", 42, 123*1000)
 	f("-123s", 42, -123*1000)
 	f("123m", 42, 123*60*1000)