Why ByteList.fromList need minLength and maxLength?

[anggaaryas]

ByteList constructor:

   ByteList.fromList(Uint8List list,
      [int minLength = _minLength, int maxLength = _maxLength])
      : _u8l = _constructList(list, minLength, maxLength);

_constructList method:

 static Uint8List _constructList(
      Iterable<int> list, int minLength, int maxLength) {
    if (list.length < minLength || list.length > maxLength) {
      throw Exception(
          'The list length (${list.length}) is invalid (min: $minLength, max: $maxLength)');
    }
    return UnmodifiableUint8ListView(Uint8List.fromList(list.toList()));
  }

[ilap]

Hi,

There can be different scenarios, so we want to be sure that the constructed class inherits ByteList can have some constraints (min and max size limit). For example classes:

• ScriptHash, which can only be 28-byte not less and not more or a strictly 32-byte length PublicKey etc.
• Signed message, which cannot be smaller than 24-byte long but can be as long as the current max length (16K) or
• Some, array whcih can be from 0 length to some specified one.

The current naming of the constructors are misleading and I am going to release a new version the v0.5.0 with API breaks which makes more sense. Also, we do not need .fromList constructor as the main creational one use Iterable.

[ilap]

Released v0.5.0 check the differences.

[muhammadsaddamnur]

Hi @ilap i have issue when using EncryptedMessage.fromList(...) error like this:

Exception: The list length (44719) is invalid (min: 24, max: 16384)

That function have limitation with _maxLength, but i can't modify value from EncryptedMessage.fromList(...) Why doesn't add maxLength params in function? do you have any concern about that?

so, currently what i did was like this :

    Uint8List encryptedMessage = encrypted.asTypedList;
    var bytelistencryptedMessage = ByteList(
      encryptedMessage,
    );
    final takenonce =
        bytelistencryptedMessage.take(EncryptedMessage.nonceLength);
    final chipherTextnonce =
        bytelistencryptedMessage.skip(EncryptedMessage.nonceLength);
    ByteList nonce = ByteList.withConstraint(takenonce,
        constraintLength: EncryptedMessage.nonceLength);
    ByteList chipherText = ByteList.withConstraint(chipherTextnonce,
        constraintLength:
            bytelistencryptedMessage.length - EncryptedMessage.nonceLength);
    final decrypted = box.decrypt(
      EncryptedMessage(
        nonce: nonce.asTypedList,
        cipherText: chipherText.asTypedList,
      ),
    );```

[ilap]

Hi,

I have set it to 16K for performance reasons, but will consider some bigger size based on the benchmark, as this is not for stream en/decryption. I will create some benchmark.

[ilap]

I have increased it to 1MB.

[ilap]

so, currently what i did was like this :

Why do you do a lot of conversions? As EncryptedMessage is a ByteList and behaves like an Uint8List. The library created for the sake of simplicity where the ByteList and the extended/inherited classes behave like an Uint8List. That is why ByteList use ListMixin<int> and an internal Uint8List.

You could just simply do the following:

// encrypted can be any Iterable<int> e.g., List<int> etc.
final encryptedMessage = EncryptedMessage.fromList(encrypted.asTypedList);
final decrypted = box.decrypt(encryptedMessage);