1 files changed, 124 insertions, 0 deletions
diff --git a/third_party/libwebrtc/system_wrappers/include/ntp_time.h b/third_party/libwebrtc/system_wrappers/include/ntp_time.h
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index 0000000000..b912bc8a0c
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+++ b/third_party/libwebrtc/system_wrappers/include/ntp_time.h
@@ -0,0 +1,124 @@
+/*
+ *  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 SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_
+#define SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_
+
+#include <cmath>
+#include <cstdint>
+#include <limits>
+
+#include "rtc_base/numerics/safe_conversions.h"
+
+namespace webrtc {
+
+class NtpTime {
+ public:
+  static constexpr uint64_t kFractionsPerSecond = 0x100000000;
+  NtpTime() : value_(0) {}
+  explicit NtpTime(uint64_t value) : value_(value) {}
+  NtpTime(uint32_t seconds, uint32_t fractions)
+      : value_(seconds * kFractionsPerSecond + fractions) {}
+
+  NtpTime(const NtpTime&) = default;
+  NtpTime& operator=(const NtpTime&) = default;
+  explicit operator uint64_t() const { return value_; }
+
+  void Set(uint32_t seconds, uint32_t fractions) {
+    value_ = seconds * kFractionsPerSecond + fractions;
+  }
+  void Reset() { value_ = 0; }
+
+  int64_t ToMs() const {
+    static constexpr double kNtpFracPerMs = 4.294967296E6;  // 2^32 / 1000.
+    const double frac_ms = static_cast<double>(fractions()) / kNtpFracPerMs;
+    return 1000 * static_cast<int64_t>(seconds()) +
+           static_cast<int64_t>(frac_ms + 0.5);
+  }
+  // NTP standard (RFC1305, section 3.1) explicitly state value 0 is invalid.
+  bool Valid() const { return value_ != 0; }
+
+  uint32_t seconds() const {
+    return rtc::dchecked_cast<uint32_t>(value_ / kFractionsPerSecond);
+  }
+  uint32_t fractions() const {
+    return rtc::dchecked_cast<uint32_t>(value_ % kFractionsPerSecond);
+  }
+
+ private:
+  uint64_t value_;
+};
+
+inline bool operator==(const NtpTime& n1, const NtpTime& n2) {
+  return static_cast<uint64_t>(n1) == static_cast<uint64_t>(n2);
+}
+inline bool operator!=(const NtpTime& n1, const NtpTime& n2) {
+  return !(n1 == n2);
+}
+
+// Converts `int64_t` milliseconds to Q32.32-formatted fixed-point seconds.
+// Performs clamping if the result overflows or underflows.
+inline int64_t Int64MsToQ32x32(int64_t milliseconds) {
+  // TODO(bugs.webrtc.org/10893): Change to use `rtc::saturated_cast` once the
+  // bug has been fixed.
+  double result =
+      std::round(milliseconds * (NtpTime::kFractionsPerSecond / 1000.0));
+
+  // Explicitly cast values to double to avoid implicit conversion warnings
+  // The conversion of the std::numeric_limits<int64_t>::max() triggers
+  // -Wimplicit-int-float-conversion warning in clang 10.0.0 without explicit
+  // cast
+  if (result <= static_cast<double>(std::numeric_limits<int64_t>::min())) {
+    return std::numeric_limits<int64_t>::min();
+  }
+
+  if (result >= static_cast<double>(std::numeric_limits<int64_t>::max())) {
+    return std::numeric_limits<int64_t>::max();
+  }
+
+  return rtc::dchecked_cast<int64_t>(result);
+}
+
+// Converts `int64_t` milliseconds to UQ32.32-formatted fixed-point seconds.
+// Performs clamping if the result overflows or underflows.
+inline uint64_t Int64MsToUQ32x32(int64_t milliseconds) {
+  // TODO(bugs.webrtc.org/10893): Change to use `rtc::saturated_cast` once the
+  // bug has been fixed.
+  double result =
+      std::round(milliseconds * (NtpTime::kFractionsPerSecond / 1000.0));
+
+  // Explicitly cast values to double to avoid implicit conversion warnings
+  // The conversion of the std::numeric_limits<int64_t>::max() triggers
+  // -Wimplicit-int-float-conversion warning in clang 10.0.0 without explicit
+  // cast
+  if (result <= static_cast<double>(std::numeric_limits<uint64_t>::min())) {
+    return std::numeric_limits<uint64_t>::min();
+  }
+
+  if (result >= static_cast<double>(std::numeric_limits<uint64_t>::max())) {
+    return std::numeric_limits<uint64_t>::max();
+  }
+
+  return rtc::dchecked_cast<uint64_t>(result);
+}
+
+// Converts Q32.32-formatted fixed-point seconds to `int64_t` milliseconds.
+inline int64_t Q32x32ToInt64Ms(int64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+// Converts UQ32.32-formatted fixed-point seconds to `int64_t` milliseconds.
+inline int64_t UQ32x32ToInt64Ms(uint64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+}  // namespace webrtc
+#endif  // SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_