Do not divide then multiply as it may result in incorrect result

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]>

Author: rtm0

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)