Add write support for the RtpStreamId and RepairedRtpStreamId header extensions.

webrtc/modules/rtp_rtcp/source/rtp_header_extensions.cc

 /*
  *  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.
  */
 
@@ skipping 239 matching lines @@
 constexpr const char* RtpStreamId::kUri;
 
 bool RtpStreamId::Parse(rtc::ArrayView<const uint8_t> data, StreamId* rsid) {
   if (data.empty() || data[0] == 0)  // Valid rsid can't be empty.
     return false;
   rsid->Set(data);
   RTC_DCHECK(!rsid->empty());
   return true;
 }
 
+bool RtpStreamId::Write(uint8_t* data, const StreamId& rsid) {
+  if (rsid.empty() || rsid.size() > StreamId::kMaxSize)
+    return false;
+  memcpy(data, rsid.data(), rsid.size());
+  return true;
+}
+
 bool RtpStreamId::Parse(rtc::ArrayView<const uint8_t> data, std::string* rsid) {
   if (data.empty() || data[0] == 0)  // Valid rsid can't be empty.
     return false;
   const char* str = reinterpret_cast<const char*>(data.data());
   // If there is a \0 character in the middle of the |data|, treat it as end of
   // the string. Well-formed rsid shouldn't contain it.
   rsid->assign(str, strnlen(str, data.size()));
   RTC_DCHECK(!rsid->empty());
   return true;
 }
 
+bool RtpStreamId::Write(uint8_t* data, const std::string& rsid) {
+  if (rsid.empty() || rsid.size() > StreamId::kMaxSize)

[danilchap, 2017/05/10 11:25:18]

may be DCHECK here:
caller must ensure |data| has exact allocated size for the |rsid|

[erikvarga1, 2017/05/10 14:48:19]

Done.

+    return false;
+  memcpy(data, rsid.data(), rsid.size());
+  return true;
+}
+
 // RepairedRtpStreamId.
 constexpr RTPExtensionType RepairedRtpStreamId::kId;
 constexpr uint8_t RepairedRtpStreamId::kValueSizeBytes;
 constexpr const char* RepairedRtpStreamId::kUri;
 
 // RtpStreamId and RepairedRtpStreamId use the same format to store rsid.
 bool RepairedRtpStreamId::Parse(rtc::ArrayView<const uint8_t> data,
                                 StreamId* rsid) {
   return RtpStreamId::Parse(data, rsid);
 }
 
+size_t RepairedRtpStreamId::ValueSize(const StreamId& rsid) {
+  return RtpStreamId::ValueSize(rsid);
+}
+
+bool RepairedRtpStreamId::Write(uint8_t* data, const StreamId& rsid) {
+  return RtpStreamId::Write(data, rsid);
+}
+
 bool RepairedRtpStreamId::Parse(rtc::ArrayView<const uint8_t> data,
                                 std::string* rsid) {
   return RtpStreamId::Parse(data, rsid);
 }
 
+size_t RepairedRtpStreamId::ValueSize(const std::string& rsid) {
+  return RtpStreamId::ValueSize(rsid);
+}
+
+bool RepairedRtpStreamId::Write(uint8_t* data, const std::string& rsid) {
+  return RtpStreamId::Write(data, rsid);
+}
+
 }  // namespace webrtc