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/*
* 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_
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