text: /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  #ifndef MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_COMMON_HEADER_H_
  #define MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_COMMON_HEADER_H_
  
  #include "rtc_base/basictypes.h"
  
  namespace webrtc {
  namespace rtcp {
  class CommonHeader {
   public:
    static constexpr size_t kHeaderSizeBytes = 4;
  
    CommonHeader() {}
    CommonHeader(const CommonHeader&) = default;
    CommonHeader& operator =(const CommonHeader&) = default;
  
    bool Parse(const uint8_t* buffer, size_t size_bytes);
  
    uint8_t type() const { return packet_type_; }
    // Depending on packet type same header field can be used either as count or
    // as feedback message type (fmt). Caller expected to know how it is used.
    uint8_t fmt() const { return count_or_format_; }
    uint8_t count() const { return count_or_format_; }
    size_t payload_size_bytes() const { return payload_size_; }
    const uint8_t* payload() const { return payload_; }
    size_t packet_size() const {
      return kHeaderSizeBytes + payload_size_ + padding_size_;
    }
    // Returns pointer to the next RTCP packet in compound packet.
    const uint8_t* NextPacket() const {
      return payload_ + payload_size_ + padding_size_;
    }
  
   private:
    uint8_t packet_type_ = 0;
    uint8_t count_or_format_ = 0;
    uint8_t padding_size_ = 0;
    uint32_t payload_size_ = 0;
    const uint8_t* payload_ = nullptr;
  };
  }  // namespace rtcp
  }  // namespace webrtc
  #endif  // MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_COMMON_HEADER_H_
  