windows-nt/Source/XPSP1/NT/base/crts/crtw32/time/dtoxtime.c
2020-09-26 16:20:57 +08:00

236 lines
7.6 KiB
C

/***
*dtoxtime.c - convert OS local time to time_t
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines __loctotime_t() - convert OS local time to internal format
* (time_t).
*
*Revision History:
* 03-??-84 RLB written
* 11-18-87 SKS change tzset() to __tzset(), change source file name
* make _dtoxtime a near procedure
* 01-26-88 SKS _dtoxtime is no longer a near procedure (for QC)
* 03-20-90 GJF Made calling type _CALLTYPE1, added #include
* <cruntime.h>, removed #include <register.h> and
* fixed the copyright. Also, cleaned up the formatting
* a bit.
* 10-04-90 GJF New-style function declarator.
* 01-21-91 GJF ANSI naming.
* 05-19-92 DJM ifndef for POSIX build.
* 03-30-93 GJF Revised. Old _dtoxtime is replaced by __gmtotime_t,
* which is more useful on Win32.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 04-06-93 GJF Rewrote computation to avoid compiler warnings.
* 07-20-93 GJF Replaced __gmtotime_t with function very similar to
* _dostotime_t() in 16-bit C 8.00. The reason for the
* change is that only local time values can be trusted
* on a Win32 platform. System time may be UTC (as
* documented), and is on NT, or may be the same as
* local time, as on Win32S and Win32C
* 02-10-95 GJF Appended Mac version of source file (somewhat cleaned
* up), with appropriate #ifdef-s.
* 09-25-95 GJF Added DST flag to __loctotime_t's arguments. Also,
* use _dstbias instead of assuming a DST bias of -3600.
* 02-07-98 GJF Changes for Win64: replaced long type with time_t
* 10-19-98 GJF Fill in tm_min and tm_sec before calling _isindst
* 05-17-99 PML Remove all Macintosh support.
* 12-10-99 GB Added support for years beyond 2099.
*
*******************************************************************************/
#ifndef _POSIX_
#include <cruntime.h>
#include <time.h>
#include <ctime.h>
#include <internal.h>
/***
*time_t __loctotime_t(yr, mo, dy, hr, mn, sc, dstflag) - converts OS local
* time to internal time format (i.e., a time_t value)
*
*Purpose:
* Converts a local time value, obtained in a broken down format from
* the host OS, to time_t format (i.e., the number elapsed seconds since
* 01-01-70, 00:00:00, UTC).
*
*Entry:
* int yr, mo, dy - date
* int hr, mn, sc - time
* int dstflag - 1 if Daylight Time, 0 if Standard Time, -1 if
* not specified.
*
*Exit:
* Returns calendar time value.
*
*Exceptions:
*
*******************************************************************************/
time_t __cdecl __loctotime_t (
int yr, /* 0 based */
int mo, /* 1 based */
int dy, /* 1 based */
int hr,
int mn,
int sc,
int dstflag )
{
int tmpdays;
time_t tmptim;
struct tm tb;
/*
* Do a quick range check on the year and convert it to a delta
* off of 1900.
*/
if ( ((yr -= 1900) < _BASE_YEAR) || (yr > _MAX_YEAR) )
return (time_t)(-1);
/*
* Compute the number of elapsed days in the current year. Note the
* test for a leap year would fail in the year 2100, if this was in
* range (which it isn't).
*/
tmpdays = dy + _days[mo - 1];
if ( _IS_LEAP_YEAR(yr) && (mo > 2) )
tmpdays++;
/*
* Compute the number of elapsed seconds since the Epoch. Note the
* computation of elapsed leap years would break down after 2100
* if such values were in range (fortunately, they aren't).
*/
tmptim = /* 365 days for each year */
(((time_t)yr - _BASE_YEAR) * 365
/* one day for each elapsed leap year */
+ (time_t)_ELAPSED_LEAP_YEARS(yr)
/* number of elapsed days in yr */
+ tmpdays)
/* convert to hours and add in hr */
* 24 + hr;
tmptim = /* convert to minutes and add in mn */
(tmptim * 60 + mn)
/* convert to seconds and add in sec */
* 60 + sc;
/*
* Account for time zone.
*/
__tzset();
tmptim += _timezone;
/*
* Fill in enough fields of tb for _isindst(), then call it to
* determine DST.
*/
tb.tm_yday = tmpdays;
tb.tm_year = yr;
tb.tm_mon = mo - 1;
tb.tm_hour = hr;
tb.tm_min = mn;
tb.tm_sec = sc;
if ( (dstflag == 1) || ((dstflag == -1) && _daylight &&
_isindst(&tb)) )
tmptim += _dstbias;
return(tmptim);
}
#if 0
/*
* THE FOLLOWING FUNCTION WAS DEFINED AND USED (IN PLACE OF THE ONE ABOVE)
* FOR THE CUDA PRODUCT AND THE NT 1.0 SDK. IT WAS REPLACED (BY THE ONE
* ABOVE) BECAUSE NON-NT WIN32 PLATFORMS MAY USE LOCAL TIME FOR SYSTEM TIME,
* RATHER THAN UTC.
*/
/***
*time_t __gmtotime_t(yr, mo, dy, hr, mn, sc) - convert broken down time (UTC)
* to time_t
*
*Purpose:
* Converts a broken down UTC (GMT) time to time_t. This is similar to
* _mkgmtime() except there is minimal overflow checking and no updating
* of the input values (i.e., the fields of tm structure).
*
*Entry:
* int yr, mo, dy - date
* int hr, mn, sc - time
*
*Exit:
* returns time_t value
*
*Exceptions:
*
*******************************************************************************/
time_t __cdecl __gmtotime_t (
int yr, /* 0 based */
int mo, /* 1 based */
int dy, /* 1 based */
int hr,
int mn,
int sc
)
{
int tmpdays;
long tmptim;
/*
* Do a quick range check on the year and convert it to a delta
* off of 1900.
*/
if ( ((long)(yr -= 1900) < _BASE_YEAR) || ((long)yr > _MAX_YEAR) )
return (time_t)(-1);
/*
* Compute the number of elapsed days in the current year minus
* one. Note the test for leap year and the would fail in the year 2100
* if this was in range (which it isn't).
*/
tmpdays = dy + _days[mo - 1];
if ( !(yr & 3) && (mo > 2) )
/*
* in a leap year, after Feb. add one day for elapsed
* Feb 29.
*/
tmpdays++;
/*
* Compute the number of elapsed seconds since the Epoch. Note the
* computation of elapsed leap years would break down after 2100
* if such values were in range (fortunately, they aren't).
*/
tmptim = /* 365 days for each year */
(((long)yr - _BASE_YEAR) * 365L
/* one day for each elapsed leap year */
+ (long)((yr - 1) >> 2) - _LEAP_YEAR_ADJUST
/* number of elapsed days in yr */
+ tmpdays)
/* convert to hours and add in hr */
* 24L + hr;
tmptim = /* convert to minutes and add in mn */
(tmptim * 60L + mn)
/* convert to seconds and add in sec */
* 60L + sc;
return (tmptim >= 0) ? (time_t)tmptim : (time_t)(-1);
}
#endif
#endif /* _POSIX_ */