92 lines
3.1 KiB
C
92 lines
3.1 KiB
C
/***
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*ctime.h - constant for dates and times
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*
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* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* Include file used by the c time routines containing definitions of
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* various constants and macros used in determining dates and times.
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*
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* [Internal]
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*
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*Revision History:
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* 03-??-84 RLB written
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* 05-??-84 DFW split out the constant from each routine into this file
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* 07-27-89 GJF Fixed copyright
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* 10-30-89 GJF Fixed copyright (again)
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* 02-28-90 GJF Added #ifndef _INC_CTIME stuff.
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* 03-29-93 GJF Revised constants.
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* 02-14-95 CFW Clean up Mac merge.
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* 03-29-95 CFW Add error message to internal headers.
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* 12-14-95 JWM Add "#pragma once".
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* 02-24-97 GJF Detab-ed.
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* 05-07-97 GJF Added _MAX_YEAR64 and _MAX_TIME64_T constants. Added
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* _IS_LEAP_YEAR() and _ELAPSED_LEAP_YEAR macros. Took
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* out unnecessary casts.
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* 02-09-98 GJF Changes for Win64: removed unnecessary typing of
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* constants as long, also put in larger value for
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* _MAX_YEAR.
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* 12-10-99 GB _MAX_YEAR for Win64 be equal to _MAX_YEAR64
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*
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****/
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#if _MSC_VER > 1000 /*IFSTRIP=IGN*/
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#pragma once
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#endif
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#ifndef _INC_CTIME
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#define _INC_CTIME
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#ifndef _CRTBLD
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/*
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* This is an internal C runtime header file. It is used when building
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* the C runtimes only. It is not to be used as a public header file.
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*/
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#error ERROR: Use of C runtime library internal header file.
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#endif /* _CRTBLD */
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/*
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* Constants
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*/
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#define _DAY_SEC (24 * 60 * 60) /* secs in a day */
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#define _YEAR_SEC (365 * _DAY_SEC) /* secs in a year */
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#define _FOUR_YEAR_SEC (1461 * _DAY_SEC) /* secs in a 4 year interval */
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#define _DEC_SEC 315532800 /* secs in 1970-1979 */
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#define _BASE_YEAR 70 /* 1970 is the base year */
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#define _BASE_DOW 4 /* 01-01-70 was a Thursday */
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#define _LEAP_YEAR_ADJUST 17 /* Leap years 1900 - 1970 */
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#ifdef _WIN64
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#define _MAX_YEAR 1099 /* 2999 is the max year */
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#else
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#define _MAX_YEAR 138 /* 2038 is the max year */
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#endif
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#define _MAX_YEAR64 1099 /* 2999 is the max year */
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#define _MAX__TIME64_T 0x100000000000i64 /* number of seconds from
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00:00:00, 01/01/1970 UTC to
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23:59:59. 12/31/2999 UTC */
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/*
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* Macro to determine if a given year, expressed as the number of years since
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* 1900, is a leap year.
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*/
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#define _IS_LEAP_YEAR(y) (((y % 4 == 0) && (y % 100 != 0)) || \
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((y + 1900) % 400 == 0))
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/*
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* Number of leap years from 1970 up to, but not including, the specified year
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* (expressed as the number of years since 1900).
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*/
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#define _ELAPSED_LEAP_YEARS(y) (((y - 1)/4) - ((y - 1)/100) + ((y + 299)/400) \
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- _LEAP_YEAR_ADJUST)
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#endif /* _INC_CTIME */
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