57 lines
2.2 KiB
C
57 lines
2.2 KiB
C
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/*
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* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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#define MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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#include <stdint.h>
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#include "system_wrappers/include/ntp_time.h"
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namespace webrtc {
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// Converts time obtained using rtc::TimeMicros to ntp format.
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// TimeMicrosToNtp guarantees difference of the returned values matches
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// difference of the passed values.
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// As a result TimeMicrosToNtp(rtc::TimeMicros()) doesn't guarantee to match
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// system time.
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// However, TimeMicrosToNtp Guarantees that returned NtpTime will be offsetted
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// from rtc::TimeMicros() by integral number of milliseconds.
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// Use NtpOffsetMs() to get that offset value.
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NtpTime TimeMicrosToNtp(int64_t time_us);
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// Difference between Ntp time and local relative time returned by
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// rtc::TimeMicros()
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int64_t NtpOffsetMs();
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// Helper function for compact ntp representation:
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// RFC 3550, Section 4. Time Format.
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// Wallclock time is represented using the timestamp format of
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// the Network Time Protocol (NTP).
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// ...
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// In some fields where a more compact representation is
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// appropriate, only the middle 32 bits are used; that is, the low 16
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// bits of the integer part and the high 16 bits of the fractional part.
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inline uint32_t CompactNtp(NtpTime ntp) {
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return (ntp.seconds() << 16) | (ntp.fractions() >> 16);
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}
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// Converts interval in microseconds to compact ntp (1/2^16 seconds) resolution.
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// Negative values converted to 0, Overlarge values converted to max uint32_t.
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uint32_t SaturatedUsToCompactNtp(int64_t us);
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// Converts interval between compact ntp timestamps to milliseconds.
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// This interval can be up to ~9.1 hours (2^15 seconds).
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// Values close to 2^16 seconds consider negative and result in minimum rtt = 1.
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int64_t CompactNtpRttToMs(uint32_t compact_ntp_interval);
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} // namespace webrtc
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#endif // MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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