Using `TcpSocketBuilder` and then the created `ByteReadChannel`, how do I read a `UInt`?

# ktor

[Edoardo Luppi]

Using TcpSocketBuilder and then the created ByteReadChannel, how do I read a UInt?

[Adam S]

so ByteReadChannel has a readInt() member function https://api.ktor.io/ktor-io/io.ktor.utils.io/-byte-read-channel/index.html#598794336%2FFunctions%2F599479352, but no readUInt() member or extension function

And so, at a guess, you could try reading the number of bytes required UInt.SIZE_BYTES and then convert them into a UInt

[Aleksei Tirman [JB]]

channel.readInt().toUInt()

[Edoardo Luppi]

Thanks! I guess the second solution would be simpler, I just don't want to mess with the binary representation

[Edoardo Luppi]

I need those unsigned ints to extract flags, bit by bit

[Adam S]

channel.readInt().toUInt()

ahh yeah, if that works 👍. I assumed it wouldn’t because UInt.MAX_VALUE is of course larger than Int.MAX_VALUE - but I guess the byte representation is the same

[Edoardo Luppi]

Follow up question: there doesn't seem to be an easy to use method to read an arbitrary amount of bytes into a byte array or buffer. Or maybe I can't find it

[Adam S]

another option for UInt, you could do readPacket(UInt.SIZE_BYTES) https://api.ktor.io/ktor-io/io.ktor.utils.io/-byte-read-channel/read-packet.html which returns a ByteReadPacket, which has a readUInt() extension

[Edoardo Luppi]

Is readPacket the most generic function to read n bytes?

[Edoardo Luppi]

There is also readFully which accepts a buffer/byte array.
Not sure what's the difference

[Edoardo Luppi]

I made it work correctly with readPacket. Thanks both!

Now I'd like to perform a write. Is there a way to concatenate two ByteReadPacket into a single ByteReadPacket? I need to perform an "atomic" write

[Edoardo Luppi]

Solved with the following code, which uses another builder

sendChannel.writePacket {
  if (serializable.autosize()) {
    writeUInt(outputStream.getWrittenBytes().toUInt())
  }

  writePacket(payloadBuilder.build())
}