Fix panic in New() with large value and negative exp (#8)

decimal.go

@@ -124,9 +124,7 @@ func New(value int64, exp int32) Decimal {
 			if value >= minInt*s && value <= maxInt*s {
 				return Decimal{fixed: value * pow10Table[precision+exp]}
 			}
-		}
-		// when exp > 7, it would be greater than maxInt
-		if exp <= 6 {
+		} else if exp <= 6 { // when exp > 6, it would be greater than maxInt
 			s := pow10Table[exp]
 			if value >= minInt/s && value <= maxInt/s {
 				return Decimal{fixed: value * pow10Table[precision+exp]}
@@ -1081,7 +1079,6 @@ func (d *NullDecimal) UnmarshalText(text []byte) error {
 
 	d.Valid = true
 	return nil
-
 }
 
 func (d NullDecimal) Value() (driver.Value, error) {

decimal_test.go

@@ -138,6 +138,18 @@ func TestDecimal(t *testing.T) {
 			shouldEqual(t, x, alpacadecimal.RequireFromString("10000000"))
 			require.False(t, x.IsOptimized())
 		}
+
+		{
+			x := alpacadecimal.New(10_000_000, 0)
+			shouldEqual(t, x, alpacadecimal.RequireFromString("10000000"))
+			require.False(t, x.IsOptimized())
+		}
+
+		{
+			x := alpacadecimal.New(1_000_000_000, -2)
+			shouldEqual(t, x, alpacadecimal.RequireFromString("10000000"))
+			require.False(t, x.IsOptimized())
+		}
 	})
 
 	t.Run("NewFromBigInt", func(t *testing.T) {
@@ -184,7 +196,6 @@ func TestDecimal(t *testing.T) {
 		require.NoError(t, err)
 
 		require.Equal(t, x.String(), y.String())
-
 	})
 
 	t.Run("NewFromInt", func(t *testing.T) {