ntp.h

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/*
 * Copyright (c) 2022 Roc Streaming authors
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
//! @file roc_packet/ntp.h
//! @brief Utitilies for NTP timestamp.
 
#ifndef ROC_PACKET_NTP_H_
#define ROC_PACKET_NTP_H_
 
#include "roc_core/time.h"
 
namespace roc {
namespace packet {
 
//! NTP timestamp.
//!
//! Format:
//!  - highest 32 bits - seconds since NTP epoch
//!  - lowest 32 bits - fractions of a second
//!
//! Epoch:
//!  - for dates in years 1968-2036, epoch starts from 1 Jan 1900 00:00:00
//!  - for dates in years 2036-2104, epoch starts from 7 Feb 2036 06:28:16
//!
//! See RFC 5905 and RFC 2030.
//!
//! See also:
//!  - https://tickelton.gitlab.io/articles/ntp-timestamps/
//!  - https://www.eecis.udel.edu/~mills/y2k.html
typedef uint64_t ntp_timestamp_t;
 
//! Convert Unix absolute time to NTP absolute time.
//! @remarks
//!  @p unix_time defines nanoseconds since Unix epoch (should belong to years 1968-2104).
ntp_timestamp_t unix_2_ntp(core::nanoseconds_t unix_time);
 
//! Convert NTP absolute time to Unix absolute time.
core::nanoseconds_t ntp_2_unix(ntp_timestamp_t ntp_time);
 
//! Convert nanoseconds delta to NTP delta.
//! @remarks
//!  @p ns_delta defines nanoseconds delta (should be positive)
ntp_timestamp_t nanoseconds_2_ntp(core::nanoseconds_t ns_delta);
 
//! Converts NTP delta to nanoseconds delta.
core::nanoseconds_t ntp_2_nanoseconds(ntp_timestamp_t ntp_delta);
 
} // namespace packet
} // namespace roc
 
#endif // ROC_PACKET_NTP_H_