Uint8List convert()

in lib/src/codepage.dart [412:443]
31 lines of code
8 McCabe index (conditional complexity)

  Uint8List convert(String input, {int? invalidCharacter}) {
    if (invalidCharacter != null) {
      RangeError.checkValueInInterval(
          invalidCharacter, 0, 255, "invalidCharacter");
    }
    var count = input.length;
    var result = Uint8List(count);
    var j = 0;
    for (var i = 0; i < count; i++) {
      var char = input.codeUnitAt(i);
      var byte = _encoding[char];
      nullCheck:
      if (byte == null) {
        // Check for surrogate.
        var offset = i;
        if (char & 0xFC00 == 0xD800 && i + 1 < count) {
          var next = input.codeUnitAt(i + 1);
          if ((next & 0xFC00) == 0xDC00) {
            i = i + 1;
            char = 0x10000 + ((char & 0x3ff) << 10) + (next & 0x3ff);
            byte = _encoding[char];
            if (byte != null) break nullCheck;
          }
        }
        byte = invalidCharacter ??
            (throw FormatException(
                "Not a character in this code page", input, offset));
      }
      result[j++] = byte;
    }
    return Uint8List.sublistView(result, 0, j);
  }