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      1 /*
      2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_HEADER_EXTENSION_H_
     12 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_HEADER_EXTENSION_H_
     13 
     14 #include <map>
     15 
     16 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
     17 #include "webrtc/typedefs.h"
     18 
     19 namespace webrtc {
     20 
     21 const uint16_t kRtpOneByteHeaderExtensionId = 0xBEDE;
     22 
     23 const size_t kRtpOneByteHeaderLength = 4;
     24 const size_t kTransmissionTimeOffsetLength = 4;
     25 const size_t kAudioLevelLength = 2;
     26 const size_t kAbsoluteSendTimeLength = 4;
     27 const size_t kVideoRotationLength = 2;
     28 const size_t kTransportSequenceNumberLength = 3;
     29 
     30 struct HeaderExtension {
     31   explicit HeaderExtension(RTPExtensionType extension_type)
     32       : type(extension_type), length(0), active(true) {
     33     Init();
     34   }
     35 
     36   HeaderExtension(RTPExtensionType extension_type, bool active)
     37       : type(extension_type), length(0), active(active) {
     38     Init();
     39   }
     40 
     41   void Init() {
     42     // TODO(solenberg): Create handler classes for header extensions so we can
     43     // get rid of switches like these as well as handling code spread out all
     44     // over.
     45     switch (type) {
     46       case kRtpExtensionTransmissionTimeOffset:
     47         length = kTransmissionTimeOffsetLength;
     48         break;
     49       case kRtpExtensionAudioLevel:
     50         length = kAudioLevelLength;
     51         break;
     52       case kRtpExtensionAbsoluteSendTime:
     53         length = kAbsoluteSendTimeLength;
     54         break;
     55       case kRtpExtensionVideoRotation:
     56         length = kVideoRotationLength;
     57         break;
     58       case kRtpExtensionTransportSequenceNumber:
     59         length = kTransportSequenceNumberLength;
     60         break;
     61       default:
     62         assert(false);
     63     }
     64   }
     65 
     66   const RTPExtensionType type;
     67   uint8_t length;
     68   bool active;
     69 };
     70 
     71 class RtpHeaderExtensionMap {
     72  public:
     73   RtpHeaderExtensionMap();
     74   ~RtpHeaderExtensionMap();
     75 
     76   void Erase();
     77 
     78   int32_t Register(const RTPExtensionType type, const uint8_t id);
     79 
     80   // Active is a concept for a registered rtp header extension which doesn't
     81   // take effect yet until being activated. Inactive RTP header extensions do
     82   // not take effect and should not be included in size calculations until they
     83   // are activated.
     84   int32_t RegisterInactive(const RTPExtensionType type, const uint8_t id);
     85   bool SetActive(const RTPExtensionType type, bool active);
     86 
     87   int32_t Deregister(const RTPExtensionType type);
     88 
     89   bool IsRegistered(RTPExtensionType type) const;
     90 
     91   int32_t GetType(const uint8_t id, RTPExtensionType* type) const;
     92 
     93   int32_t GetId(const RTPExtensionType type, uint8_t* id) const;
     94 
     95   //
     96   // Methods below ignore any inactive rtp header extensions.
     97   //
     98 
     99   size_t GetTotalLengthInBytes() const;
    100 
    101   int32_t GetLengthUntilBlockStartInBytes(const RTPExtensionType type) const;
    102 
    103   void GetCopy(RtpHeaderExtensionMap* map) const;
    104 
    105   int32_t Size() const;
    106 
    107   RTPExtensionType First() const;
    108 
    109   RTPExtensionType Next(RTPExtensionType type) const;
    110 
    111  private:
    112   int32_t Register(const RTPExtensionType type, const uint8_t id, bool active);
    113   std::map<uint8_t, HeaderExtension*> extensionMap_;
    114 };
    115 }  // namespace webrtc
    116 
    117 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_HEADER_EXTENSION_H_
    118 
    119