decode static method

List<int> decode(String input)

Decodes a base58 string into a byte-array

Implementation

static List<int> decode(String input) {
  if (input.isEmpty) {
    return Uint8List(0);
  }

  // generate base 58 index list from input string
  var input58 = List<int>.generate(input.length, (int index) => 0);
  for (var i = 0; i < input.length; i++) {
    var charint = ALPHABET.indexOf(input[i]);
    if (charint < 0) {
      throw FormatException('Invalid input formatting for Base58 decoding.');
    }
    input58[i] = charint;
  }

  // count leading zeroes
  var leadingZeroes = 0;
  while (leadingZeroes < input58.length && input58[leadingZeroes] == 0) {
    leadingZeroes++;
  }

  // decode
  var output = Uint8List(input.length);
  var j = output.length;
  var startAt = leadingZeroes;
  while (startAt < input58.length) {
    var mod = _divmod256(input58, startAt);
    if (input58[startAt] == 0) {
      startAt++;
    }
    output[--j] = mod;
  }

  // remove unnecessary leading zeroes
  while (j < output.length && output[j] == 0) {
    j++;
  }
  return output.sublist(j - leadingZeroes);
}