vendor_libs/test_vendor_lib/model/devices/hci_packetizer.h

//
// Copyright 2017 The Android Open Source Project
//
// 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
//
// http://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.
//

#pragma once

#include <functional>
#include <vector>

#include "include/hci.h"

namespace test_vendor_lib {
namespace hci {

using HciPacketReadyCallback = std::function<void(void)>;

class HciPacketizer {
 public:
  HciPacketizer(HciPacketReadyCallback packet_cb) : packet_ready_cb_(packet_cb){};
  void OnDataReady(int fd, hci::PacketType packet_type);
  const std::vector<uint8_t>& GetPacket() const;

 private:
  // 2 bytes for opcode, 1 byte for parameter length (Volume 2, Part E, 5.4.1)
  static constexpr size_t COMMAND_PREAMBLE_SIZE = 3;
  static constexpr size_t COMMAND_LENGTH_OFFSET = 2;

  // 2 bytes for handle, 2 bytes for data length (Volume 2, Part E, 5.4.2)
  static constexpr size_t ACL_PREAMBLE_SIZE = 4;
  static constexpr size_t ACL_LENGTH_OFFSET = 2;

  // 2 bytes for handle, 1 byte for data length (Volume 2, Part E, 5.4.3)
  static constexpr size_t SCO_PREAMBLE_SIZE = 3;
  static constexpr size_t SCO_LENGTH_OFFSET = 2;

  // 1 byte for event code, 1 byte for parameter length (Volume 2, Part
  // E, 5.4.4)
  static constexpr size_t EVENT_PREAMBLE_SIZE = 2;
  static constexpr size_t EVENT_LENGTH_OFFSET = 1;

  static constexpr size_t PREAMBLE_SIZE_MAX = ACL_PREAMBLE_SIZE;

  size_t HciGetPacketLengthForType(hci::PacketType type, const uint8_t* preamble);

 protected:
  enum State { HCI_PREAMBLE, HCI_PAYLOAD };
  State state_{HCI_PREAMBLE};
  uint8_t preamble_[PREAMBLE_SIZE_MAX];
  std::vector<uint8_t> packet_;
  size_t bytes_remaining_{0};
  size_t bytes_read_{0};
  HciPacketReadyCallback packet_ready_cb_;
};

}  // namespace hci
}  // namespace test_vendor_lib