decodeData method

@override Uint8List decodeData(String part)

Decodes quoted-printable content to its raw bytes.

Unlike decodeText this applies no charset: an attachment's bytes are the message's payload, not text. Returning the undecoded source here, which is what this used to do, hands the caller =25PDF=2D1=2E7 where it asked for %PDF-1.7, so every quoted-printable attachment saved or previewed came out corrupt.

Implementation

@override
Uint8List decodeData(String part) {
  // Soft line breaks carry no data.
  final cleaned = part.replaceAll('=\r\n', '').replaceAll('=\n', '');
  final out = Uint8List(cleaned.length);
  var length = 0;
  for (var i = 0; i < cleaned.length; i++) {
    final codeUnit = cleaned.codeUnitAt(i);
    if (codeUnit == AsciiRunes.runeEquals && i + 2 < cleaned.length) {
      final byte = int.tryParse(cleaned.substring(i + 1, i + 3), radix: 16);
      if (byte != null) {
        out[length++] = byte;
        i += 2;
        continue;
      }
    }
    out[length++] = codeUnit & 0xFF;
  }

  return Uint8List.sublistView(out, 0, length);
}