encodeBigInt function Null safety

Uint8List encodeBigInt(
  1. BigInt input,
  2. {Endian endian = Endian.be,
  3. int length = 0}
)

Implementation

Uint8List encodeBigInt(BigInt input,
    {Endian endian = Endian.be, int length = 0}) {
  int byteLength = (input.bitLength + 7) >> 3;
  int reqLength = length > 0 ? length : max(1, byteLength);
  assert(byteLength <= reqLength, 'byte array longer than desired length');
  assert(reqLength > 0, 'Requested array length <= 0');

  var res = Uint8List(reqLength);
  res.fillRange(0, reqLength - byteLength, 0);

  var q = input;
  if (endian == Endian.be) {
    for (int i = 0; i < byteLength; i++) {
      res[reqLength - i - 1] = (q & _byteMask).toInt();
      q = q >> 8;
    }
    return res;
  } else {
    // FIXME: le
    throw UnimplementedError('little-endian is not supported');
  }
}