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// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.github.google.bumble.btbench
import android.bluetooth.BluetoothSocket
import java.io.IOException
import java.nio.ByteBuffer
import java.util.logging.Logger
import kotlin.math.min
private val Log = Logger.getLogger("btbench.packet")
fun ByteArray.toHex(): String = joinToString(separator = "") { eachByte -> "%02x".format(eachByte) }
abstract class Packet(val type: Int, val payload: ByteArray = ByteArray(0)) {
companion object {
const val RESET = 0
const val SEQUENCE = 1
const val ACK = 2
const val LAST_FLAG = 1
fun from(data: ByteArray): Packet {
return when (data[0].toInt()) {
RESET -> ResetPacket()
SEQUENCE -> SequencePacket(
data[1].toInt(),
ByteBuffer.wrap(data, 2, 4).getInt(),
data.sliceArray(6..<data.size)
)
ACK -> AckPacket(data[1].toInt(), ByteBuffer.wrap(data, 2, 4).getInt())
else -> GenericPacket(data[0].toInt(), data.sliceArray(1..<data.size))
}
}
}
open fun toBytes(): ByteArray {
return ByteBuffer.allocate(1 + payload.size).put(type.toByte()).put(payload).array()
}
}
class GenericPacket(type: Int, payload: ByteArray) : Packet(type, payload)
class ResetPacket : Packet(RESET)
class AckPacket(val flags: Int, val sequenceNumber: Int) : Packet(ACK) {
override fun toBytes(): ByteArray {
return ByteBuffer.allocate(1 + 1 + 4).put(type.toByte()).put(flags.toByte())
.putInt(sequenceNumber).array()
}
}
class SequencePacket(val flags: Int, val sequenceNumber: Int, payload: ByteArray) :
Packet(SEQUENCE, payload) {
override fun toBytes(): ByteArray {
return ByteBuffer.allocate(1 + 1 + 4 + payload.size).put(type.toByte()).put(flags.toByte())
.putInt(sequenceNumber).put(payload).array()
}
}
abstract class PacketSink {
fun onPacket(packet: Packet) {
when (packet) {
is ResetPacket -> onResetPacket()
is AckPacket -> onAckPacket()
is SequencePacket -> onSequencePacket(packet)
}
}
abstract fun onResetPacket()
abstract fun onAckPacket()
abstract fun onSequencePacket(packet: SequencePacket)
}
interface DataSink {
fun onData(data: ByteArray)
}
interface PacketIO {
var packetSink: PacketSink?
fun sendPacket(packet: Packet)
}
class StreamedPacketIO(private val dataSink: DataSink) : PacketIO {
private var bytesNeeded: Int = 0
private var rxPacket: ByteBuffer? = null
private var rxHeader = ByteBuffer.allocate(2)
override var packetSink: PacketSink? = null
fun onData(data: ByteArray) {
var current = data
while (current.isNotEmpty()) {
if (bytesNeeded > 0) {
val chunk = current.sliceArray(0..<min(bytesNeeded, current.size))
rxPacket!!.put(chunk)
current = current.sliceArray(chunk.size..<current.size)
bytesNeeded -= chunk.size
if (bytesNeeded == 0) {
// Packet completed.
//Log.fine("packet complete: ${current.toHex()}")
packetSink?.onPacket(Packet.from(rxPacket!!.array()))
// Reset.
reset()
}
} else {
val headerBytesNeeded = 2 - rxHeader.position()
val headerBytes = current.sliceArray(0..<min(headerBytesNeeded, current.size))
current = current.sliceArray(headerBytes.size..<current.size)
rxHeader.put(headerBytes)
if (rxHeader.position() != 2) {
return
}
bytesNeeded = rxHeader.getShort(0).toInt()
if (bytesNeeded == 0) {
Log.warning("found 0 size packet!")
reset()
return
}
rxPacket = ByteBuffer.allocate(bytesNeeded)
}
}
}
private fun reset() {
rxPacket = null
rxHeader.position(0)
}
override fun sendPacket(packet: Packet) {
val packetBytes = packet.toBytes()
val packetData =
ByteBuffer.allocate(2 + packetBytes.size).putShort(packetBytes.size.toShort())
.put(packetBytes).array()
dataSink.onData(packetData)
}
}
class SocketDataSink(private val socket: BluetoothSocket) : DataSink {
override fun onData(data: ByteArray) {
socket.outputStream.write(data)
}
}
class SocketDataSource(
private val socket: BluetoothSocket,
private val onData: (data: ByteArray) -> Unit
) {
fun receive() {
val buffer = ByteArray(4096)
do {
try {
val bytesRead = socket.inputStream.read(buffer)
if (bytesRead <= 0) {
break
}
onData(buffer.sliceArray(0..<bytesRead))
} catch (error: IOException) {
Log.warning("IO Exception: $error")
break
}
} while (true)
Log.info("end of stream")
}
}
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