Introduce helper class NtpTime

webrtc/modules/rtp_rtcp/source/ntp_time.h

+/*
+*  Copyright (c) 2015 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 WEBRTC_MODULES_RTP_RTCP_SOURCE_NTP_TIME_H_
+#define WEBRTC_MODULES_RTP_RTCP_SOURCE_NTP_TIME_H_
+
+#include "webrtc/base/basictypes.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+namespace rtcp {
+
+class NtpTime {
+ public:
+  NtpTime() : seconds_(0), fractions_(0) {}
+  explicit NtpTime(const Clock& clock) {
+    clock.CurrentNtp(seconds_, fractions_);
+  }
+  NtpTime(uint32_t seconds, uint32_t fractions)
+      : seconds_(seconds), fractions_(fractions) {}
+
+  NtpTime(const NtpTime&) = default;
+  NtpTime& operator=(const NtpTime&) = default;
+
+  void SetCurrent(const Clock& clock) {
+    clock.CurrentNtp(seconds_, fractions_);
+  }
+  void Set(uint32_t seconds, uint32_t fractions) {
+    seconds_ = seconds;
+    fractions_ = fractions;
+  }
+  void Reset() {
+    seconds_ = 0;
+    fractions_ = 0;
+  }
+
+  int64_t ToMs() const { return Clock::NtpToMs(seconds_, fractions_); }
+  // RFC3611, section 4.5. DLRR Report Block.
+  // Used to calculate delays in 1/65536 seconds.
+  uint32_t MidNtp() const { return (seconds_ << 16) | (fractions_ >> 16); }
+
+  // NTP standard (RFC1305, section 3.1) explicitly state value 0/0 is invalid.
+  bool Valid() const { return !(seconds_ == 0 && fractions_ == 0); }
+
+  uint32_t seconds() const { return seconds_; }
+  uint32_t fractions() const { return fractions_; }
+
+ private:
+  uint32_t seconds_;
+  uint32_t fractions_;
+};
+
+inline bool operator==(const NtpTime& n1, const NtpTime& n2) {
+  return n1.seconds() == n2.seconds() && n1.fractions() == n2.fractions();
+}
+inline bool operator!=(const NtpTime& n1, const NtpTime& n2) {
+  return !(n1 == n2);
+}
+
+}  // namespace rtcp
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_NTP_TIME_H_