[Draft] RtpPacket sketched.

webrtc/modules/rtp_rtcp/source/rtp_header_extensions_manager.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.
+ */
+
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions_manager.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h"
+
+namespace webrtc {
+
+RtpHeaderExtensionsManager::RtpHeaderExtensionsManager() {
+  for (ExtensionType& extension : id_to_type_) {
+    extension = kInvalidType;
+  }
+}
+
+bool RtpHeaderExtensionsManager::RegisterByName(const std::string& name,
+                                                MediaType type,
+                                                uint8_t id) {
+  return TryRegister<AbsoluteSendTime>(name, type, id) ||
+         TryRegister<AudioLevel>(name, type, id) ||
+         TryRegister<TransmissionOffset>(name, type, id) ||
+         TryRegister<TransportSequenceNumber>(name, type, id) ||
+         TryRegister<VideoOrientation>(name, type, id);
+}
+
+bool RtpHeaderExtensionsManager::Register(ExtensionType type, uint8_t id) {
+  RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
+  RTC_CHECK(kMinId <= id && id <= kMaxId);
+  if (id_to_type_[id - 1] != kInvalidType) {
+    LOG(LS_ERROR) << "Extension with id " << static_cast<int>(id)
+                  << " already registered";
+    return false;
+  }
+  id_to_type_[id - 1] = type;
+  return true;
+}
+
+uint8_t RtpHeaderExtensionsManager::GetId(ExtensionType type) const {
+  for (uint8_t i = kMinId; i <= kMaxId; ++i) {
+    if (id_to_type_[i - 1] == type) {
+      return i;
+    }
+  }
+  return kInvalidId;
+}
+}  // namespace webrtc