@HiveDecimalVersionV2
  public boolean isByte() {
    return fastIsByte();
  }
Is the decimal value a byte? Range -128            to      127.
                                   Byte.MIN_VALUE          Byte.MAX_VALUE
<p>
Emulates testing for no value corruption:
     bigDecimalValue().setScale(0).equals(BigDecimal.valueOf(bigDecimalValue().byteValue()))
<p>
NOTE: Fractional digits are ignored in the test since byteValue() will
      remove them (round down).
<p>
@return True when byteValue() will return a correct byte.
storage-api/src/java/org/apache/hadoop/hive/common/type/HiveDecimal.java