dtoxtime.c

C标准库源代码

/***
*dtoxtime.c - convert OS local time to time_t
*
*       Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines __loctotime_t() - convert OS local time to internal format
*       (time_t).
*
*******************************************************************************/

#ifdef _WIN32



#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;
        long tmptim;
        struct tm tb;

        /*
         * 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. 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 ( !(yr & 3) && (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 */
                 (((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;
        /*
         * 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;
        if ( (dstflag == 1) || ((dstflag == -1) && _daylight &&
                                _isindst(&tb)) )
                tmptim += _dstbias;
        return(tmptim);
}





#else  /* _WIN32 */

#if defined (_M_MPPC) || defined (_M_M68K)


#include <cruntime.h>
#include <time.h>
#include <ctime.h>
#include <internal.h>

/***
*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;
        struct tm tb;

        /*
         * 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 = (long)yr - _BASE_YEAR;

        tmptim = /* 365 days for each year */
                 ( ( ( ( tmptim ) * 365L

                 /* one day for each elapsed leap year */
                 + ((long)(yr - 1) >> 2) - (long)_LEAP_YEAR_ADJUST

                 /* number of elapsed days in yr */
                 + (long)tmpdays )

                 /* convert to hours and add in hr */
                 * 24L + (long)hr )

                 /* convert to minutes and add in mn */
                 * 60L + (long)mn )

                 /* convert to seconds and add in sec */
                 * 60L + (long)sc;

        _tzset();

        tmptim += _timezone;        //timezone adjustment


        /*
         * Fill in enough fields of tb struct 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;
        if (_daylight && _isindst(&tb))
                tmptim -= 3600L;

        return (tmptim >= 0) ? (time_t)tmptim : (time_t)(-1);
}


#endif  /* defined (_M_MPPC) || defined (_M_M68K) */

#endif  /* _WIN32 */