encode method

@override Uint8List encode(dynamic value)

ABI-encode value as a 32-byte-aligned Uint8List. For dynamic types, returns the tail; the caller places the offset in the head.

Implementation

@override
Uint8List encode(dynamic value) {
  final BigInt v;
  if (value is BigInt) {
    v = value;
  } else if (value is int) {
    v = BigInt.from(value);
  } else {
    throw ArgumentError('Expected int or BigInt, got ${value.runtimeType}');
  }

  final minVal = -(BigInt.one << (bits - 1));
  final maxVal = (BigInt.one << (bits - 1)) - BigInt.one;
  if (v < minVal || v > maxVal) {
    throw ArgumentError('Value $v out of int$bits range [$minVal..$maxVal]');
  }

  // Two's complement into 256-bit slot.
  final encoded = v < BigInt.zero ? (BigInt.one << 256) + v : v;
  return _bigIntToBytes32(encoded);
}