public static int fastBigIntegerBytes(
      final int fastSignum, long fast0, long fast1, long fast2,
      int fastIntegerDigitCount, int fastScale,
      int fastSerializeScale,
      long[] scratchLongs, byte[] buffer) {
    if (fastSerializeScale != -1) {
      return
          fastBigIntegerBytesScaled(
              fastSignum, fast0, fast1, fast2,
              fastIntegerDigitCount, fastScale,
              fastSerializeScale,
              scratchLongs, buffer);
    } else {
      return
          fastBigIntegerBytesUnscaled(
              fastSignum, fast0, fast1, fast2,
              scratchLongs, buffer);
    }
  }
When fastSetFromBigIntegerBytesAndScale can handle the input because it is too large,
we fall back to this.
storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java