myvtm/Other/libvideoframework/rtp_header_extension/rtp_header_extension_parser.cpp

#include "../rtp_header_extension/rtp_header_extension_parser.h"

#include <string.h>

#include "../rtp_header_extension/rtp_header_extension_map.h"
#include "../rtp_header_extension/byte_io.h"
#include "../rtp_header_extension/rtp_header_extensions.h"


class RTPHeaderExtensionParserImpl : public RTPHeaderExtensionParser {
 public:

  bool Parse(const uint8_t* packet,
             size_t length,
             RTPHeaderExtension* header,
			 int *header_length);

  bool RegisterRtpHeaderExtension(RTPExtensionType type, uint8_t id);
  bool RegisterRtpHeaderExtension(RtpExtension extension) ;

  bool DeregisterRtpHeaderExtension(RTPExtensionType type) ;
  bool DeregisterRtpHeaderExtension(RtpExtension extension) ;

 private:
  RtpHeaderExtensionMap rtp_header_extension_map_;
};

RTPHeaderExtensionParser* RTPHeaderExtensionParser::Create() {
  return new RTPHeaderExtensionParserImpl();
}


bool RTPHeaderExtensionParserImpl::Parse(const uint8_t* packet,
                                size_t length,
                                RTPHeaderExtension* header,
								int *header_length) {
  RtpUtility::RTPHeaderExtensionParser rtp_parser(packet, length);
  *header = RTPHeaderExtension();

  RtpHeaderExtensionMap map;
  {
    map = rtp_header_extension_map_;
  }

  const bool valid_rtpheader = rtp_parser.Parse(header, &map, header_length);
  if (!valid_rtpheader) {
    return false;
  }
  return true;
}
bool RTPHeaderExtensionParserImpl::RegisterRtpHeaderExtension(RtpExtension extension) {
  return rtp_header_extension_map_.RegisterByUri(extension.id, extension.uri);
}

bool RTPHeaderExtensionParserImpl::RegisterRtpHeaderExtension(RTPExtensionType type,
                                                     uint8_t id) {
  return rtp_header_extension_map_.RegisterByType(id, type);
}

bool RTPHeaderExtensionParserImpl::DeregisterRtpHeaderExtension(RtpExtension extension) {
  return rtp_header_extension_map_.Deregister(
      rtp_header_extension_map_.GetType(extension.id));
}

bool RTPHeaderExtensionParserImpl::DeregisterRtpHeaderExtension(RTPExtensionType type) {
  return rtp_header_extension_map_.Deregister(type) == 0;
}


namespace RtpUtility {

RTPHeaderExtensionParser::RTPHeaderExtensionParser(const uint8_t* rtpData,
                                 const size_t rtpDataLength)
    : _ptrRTPDataBegin(rtpData),
      _ptrRTPDataEnd(rtpData ? (rtpData + rtpDataLength) : NULL) {}



bool RTPHeaderExtensionParser::Parse(RTPHeaderExtension* header,
                            const RtpHeaderExtensionMap* ptrExtensionMap,
                            int *header_length) {
  const int length = _ptrRTPDataEnd - _ptrRTPDataBegin;
  
  const uint8_t* ptr = &_ptrRTPDataBegin[0];

  // If in effect, MAY be omitted for those packets for which the offset
  // is zero.
  header->hasTransmissionTimeOffset = false;
  header->transmissionTimeOffset = 0;

  // May not be present in packet.
  header->hasAbsoluteSendTime = false;
  header->absoluteSendTime = 0;

  // May not be present in packet.
  header->hasAudioLevel = false;
  header->voiceActivity = false;
  header->audioLevel = 0;

  // May not be present in packet.
  header->hasVideoRotation = false;
  header->videoRotation = kVideoRotation_0;

  // May not be present in packet.
  header->playout_delay.min_ms = -1;
  header->playout_delay.max_ms = -1;

  // May not be present in packet.
  header->hasVideoContentType = false;
  header->videoContentType = VideoContentType::UNSPECIFIED;

  *header_length = 0;

    /* RTP header extension, RFC 3550.
     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |      defined by profile       |           length              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        header extension                       |
    |                             ....                              |
    */
    const int remain = _ptrRTPDataEnd - ptr;
    if (remain < 4) {
      return false;
    }

    *header_length += 4;

    uint16_t definedByProfile = ByteReader<uint16_t>::ReadBigEndian(ptr);
    ptr += 2;

    // in 32 bit words
    size_t XLen = ByteReader<uint16_t>::ReadBigEndian(ptr);
    ptr += 2;
    XLen *= 4;  // in bytes

    if (static_cast<size_t>(remain) < (4 + XLen)) {
      return false;
    }
    static const uint16_t kRtpOneByteHeaderExtensionId = 0xBEDE;
    if (definedByProfile == kRtpOneByteHeaderExtensionId) {
      const uint8_t* ptrRTPDataExtensionEnd = ptr + XLen;
      ParseOneByteExtensionHeader(header, ptrExtensionMap,
                                  ptrRTPDataExtensionEnd, ptr);
    }
    *header_length += XLen;


  if (*header_length > static_cast<size_t>(length))
    return false;
  
  return true;
}

void RTPHeaderExtensionParser::ParseOneByteExtensionHeader(
    RTPHeaderExtension* header,
    const RtpHeaderExtensionMap* ptrExtensionMap,
    const uint8_t* ptrRTPDataExtensionEnd,
    const uint8_t* ptr) const {
  if (!ptrExtensionMap) {
    return;
  }

  while (ptrRTPDataExtensionEnd - ptr > 0) {
    //  0
    //  0 1 2 3 4 5 6 7
    // +-+-+-+-+-+-+-+-+
    // |  ID   |  len  |
    // +-+-+-+-+-+-+-+-+

    // Note that 'len' is the header extension element length, which is the
    // number of bytes - 1.
    const int id = (*ptr & 0xf0) >> 4;
    const int len = (*ptr & 0x0f);
    ptr++;

    if (id == 0) {
      // Padding byte, skip ignoring len.
      continue;
    }

    if (id == 15) {
      return;
    }

    if (ptrRTPDataExtensionEnd - ptr < (len + 1)) {
      return;
    }

    RTPExtensionType type = ptrExtensionMap->GetType(id);
    if (type == RtpHeaderExtensionMap::kInvalidType) {
      // If we encounter an unknown extension, just skip over it.
    } else {
      switch (type) {
        case kRtpExtensionTransmissionTimeOffset: {
          if (len != 2) {
            return;
          }
          //  0                   1                   2                   3
          //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          // |  ID   | len=2 |              transmission offset              |
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          header->transmissionTimeOffset =
              ByteReader<int32_t, 3>::ReadBigEndian(ptr);
          header->hasTransmissionTimeOffset = true;
          break;
        }
        case kRtpExtensionAudioLevel: {
          if (len != 0) {
            return;
          }
          //  0                   1
          //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          // |  ID   | len=0 |V|   level     |
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          //
          header->audioLevel = ptr[0] & 0x7f;
          header->voiceActivity = (ptr[0] & 0x80) != 0;
          header->hasAudioLevel = true;
          break;
        }
        case kRtpExtensionAbsoluteSendTime: {
          if (len != 2) {
            return;
          }
          //  0                   1                   2                   3
          //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          // |  ID   | len=2 |              absolute send time               |
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          header->absoluteSendTime =
              ByteReader<uint32_t, 3>::ReadBigEndian(ptr);
          header->hasAbsoluteSendTime = true;
          break;
        }
        case kRtpExtensionVideoRotation: {
          if (len != 0) {
            return;
          }
          //  0                   1
          //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          // |  ID   | len=0 |0 0 0 0 C F R R|
          // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          header->hasVideoRotation = true;
          header->videoRotation =
              ConvertCVOByteToVideoRotation(ptr[0]);
          break;
        }
        case kRtpExtensionTransportSequenceNumber: {
          if (len != 1) {
            return;
          }
          //   0                   1                   2
          //   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
          //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          //  |  ID   | L=1   |transport wide sequence number |
          //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          uint16_t sequence_number = ptr[0] << 8;
          sequence_number += ptr[1];
          header->transportSequenceNumber = sequence_number;
          header->hasTransportSequenceNumber = true;
          break;
        }
        case kRtpExtensionPlayoutDelay: {
          if (len != 2) {
            return;
          }
          //   0                   1                   2                   3
          //   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
          //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          //  |  ID   | len=2 |   MIN delay           |   MAX delay           |
          //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          int min_playout_delay = (ptr[0] << 4) | ((ptr[1] >> 4) & 0xf);
          int max_playout_delay = ((ptr[1] & 0xf) << 8) | ptr[2];
          header->playout_delay.min_ms =
              min_playout_delay * PlayoutDelayLimits::kGranularityMs;
          header->playout_delay.max_ms =
              max_playout_delay * PlayoutDelayLimits::kGranularityMs;
          break;
        }
        case kRtpExtensionVideoContentType: {
          if (len != 0) {
            return;
          }
          //    0                   1
          //    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
          //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          //   |  ID   | len=0 | Content type  |
          //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          header->hasVideoContentType = true;
          header->videoContentType =
              static_cast<VideoContentType>(ptr[0]);
          
          break;
        }
        case kRtpExtensionRtpStreamId: {
          std::string name(reinterpret_cast<const char*>(ptr), len + 1);
          header->stream_id = name;
          break;
        }
        case kRtpExtensionRepairedRtpStreamId: {
          std::string name(reinterpret_cast<const char*>(ptr), len + 1);
          header->repaired_stream_id = name;
          break;
        }
        case kRtpExtensionMid: {
          std::string name(reinterpret_cast<const char*>(ptr), len + 1);
          header->mid = name;
          break;
        }
        case kRtpExtensionNone:
        case kRtpExtensionNumberOfExtensions: {
          return;
        }
      }
    }
    ptr += (len + 1);
  }
}

}