forked from osmocom/wireshark
58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/* epochs.h
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* Definitions of epoch values for various absolute time types.
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 2006 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#ifndef __EPOCHS_H__
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#define __EPOCHS_H__
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#include <glib.h>
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/*
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* Deltas between the epochs for various non-UN*X time stamp formats and
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* the January 1, 1970, 00:00:00 (proleptic?) UTC epoch for the UN*X time
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* stamp format.
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*/
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/*
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* 1900-01-01 00:00:00 (proleptic?) UTC.
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* Used by a number of time formats.
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*/
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#define EPOCH_DELTA_1900_01_01_00_00_00_UTC 2208988800U
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/*
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* 1904-01-01 00:00:00 (proleptic?) UTC.
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* Used in the classic Mac OS, and by formats, such as MPEG-4 Part 14 (MP4),
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* which is based on Apple's QuickTime format.
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*/
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#define EPOCH_DELTA_1904_01_01_00_00_00_UTC 2082844800U
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/*
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* 1601-01-01 (proleptic Gregorian) 00:00:00 (proleptic?) UTC.
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* The Windows NT epoch, used in a number of places.
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*
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* This is
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*
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* 369*365.25*24*60*60-(3*24*60*60+6*60*60)
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*
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* 1970-1601 is 369; 365.25 is the average length of a year in days,
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* including leap years.
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*
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* 3 days are subtracted because 1700, 1800, and 1900 were not leap
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* years, as, while they're all evenly divisible by 4, they're also
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* evently divisible by 100, but not evently divisible by 400, so
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* we need to compensate for using the average length of a year in
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* days, which assumes a leap year every 4 years, *including* every
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* 100 years.
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*
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* I'm not sure what the extra 6 hours are that are being subtracted.
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*/
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#define EPOCH_DELTA_1601_01_01_00_00_00_UTC G_GUINT64_CONSTANT(11644473600)
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#endif /* __EPOCHS_H__ */
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