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/***
*mktime.c - Convert struct tm value to __time32_t value.
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines _mktime32() and _mkgmtime32(), routines to converts a time value
* in a tm structure (possibly incomplete) into a __time32_t value, then
* update (all) the structure fields with "normalized" values.
*
*******************************************************************************/#include
#include
#include
#include
#include/*
* ChkAdd evaluates to TRUE if dest = src1 + src2 has overflowed
*/
#define ChkAdd(dest, src1, src2) ( ((src1 >= 0L) && (src2 >= 0L) \
&& (dest < 0L)) || ((src1 < 0L) && (src2 < 0L) && (dest >= 0L)) )/*
* ChkMul evaluates to TRUE if dest = src1 * src2 has overflowed
*/
#define ChkMul(dest, src1, src2) ( src1 ? (dest/src1 != src2) : 0 )
/*
* Core function for both _mktime32() and _mkgmtime32()
*/
static __time32_t __cdecl _make__time32_t( struct tm *, int);
/***
*__time32_t _mktime32(tb) - Normalize user time block structure
*
*Purpose:
* _mktime32 converts a time structure, passed in as an argument, into a
* calendar time value in internal format (__time32_t). It also completes
* and updates the fields the of the passed in structure with 'normalized'
* values. There are three practical uses for this routine:
*
* (1) Convert broken-down time to internal time format (__time32_t).
* (2) To have _mktime32 fill in the tm_wday, tm_yday, or tm_isdst fields.
* (3) To pass in a time structure with 'out of range' values for some
* fields and have _mktime32 "normalize" them (e.g., pass in 1/35/87 and
* get back 2/4/87).
*Entry:
* struct tm *tb - pointer to a tm time structure to convert and
* normalize
*
*Exit:
* If successful, _mktime32 returns the specified calender time encoded as
* a __time32_t value. Otherwise, (__time32_t)(-1) is returned to indicate an
* error.
*
*Exceptions:
* None.
*
*******************************************************************************/_CRTIMP __time32_t __cdecl _mktime32 (
struct tm *tb
)
{
return( _make__time32_t(tb, 1) );
}
/***
*__time32_t _mkgmtime32(tb) - Convert broken down UTC time to __time32_t
*
*Purpose:
* Convert a tm structure, passed in as an argument, containing a UTC
* time value to internal format (__time32_t). It also completes and updates
* the fields the of the passed in structure with 'normalized' values.*Entry:
* struct tm *tb - pointer to a tm time structure to convert and
* normalize
*
*Exit:
* If successful, _mkgmtime returns the calender time encoded as __time32_t
* Otherwise, (__time32_t)(-1) is returned to indicate an error.
*
*Exceptions:
* None.
*
*******************************************************************************/_CRTIMP __time32_t __cdecl _mkgmtime32 (
struct tm *tb
)
{
return( _make__time32_t(tb, 0) );
}
/***
*static __time32_t _make__time32_t(tb, ultflag) -
*
*Purpose:
* Converts a struct tm value to a __time32_t value, then updates the struct
* tm value. Either local time or UTC is supported, based on ultflag.
* This is the routine that actually does the work for both _mktime32() and
* _mkgmtime32().
*
*Entry:
* struct tm *tb - pointer to a tm time structure to convert and
* normalize
* int ultflag - use local time flag. the tb structure is assumed
* to represent a local date/time if ultflag > 0.
* otherwise, UTC is assumed.
*
*Exit:
* If successful, _mktime32 returns the specified calender time encoded as
* a __time32_t value. Otherwise, (__time32_t)(-1) is returned to
* indicate an error.
*
*Exceptions:
* None.
*
*******************************************************************************/static __time32_t __cdecl _make__time32_t (
struct tm *tb,
int ultflag
)
{
__time32_t tmptm1, tmptm2, tmptm3;
struct tm tbtemp;
long dstbias = 0;
long timezone = 0;_VALIDATE_RETURN( ( tb != NULL ), EINVAL, ( ( __time32_t )( -1 ) ) )
/*
* First, make sure tm_year is reasonably close to being in range.
*/
if ( ((tmptm1 = tb->tm_year) < _BASE_YEAR - 1) || (tmptm1 > _MAX_YEAR
+ 1) )
goto err_mktime;
/*
* Adjust month value so it is in the range 0 - 11. This is because
* we don't know how many days are in months 12, 13, 14, etc.
*/if ( (tb->tm_mon < 0) || (tb->tm_mon > 11) ) {
/*
* no danger of overflow because the range check above.
*/
tmptm1 += (tb->tm_mon / 12);if ( (tb->tm_mon %= 12) < 0 ) {
tb->tm_mon += 12;
tmptm1--;
}/*
* Make sure year count is still in range.
*/
if ( (tmptm1 < _BASE_YEAR - 1) || (tmptm1 > _MAX_YEAR + 1) )
goto err_mktime;
}/***** HERE: tmptm1 holds number of elapsed years *****/
/*
* Calculate days elapsed minus one, in the given year, to the given
* month. Check for leap year and adjust if necessary.
*/
tmptm2 = _days[tb->tm_mon];
if ( !(tmptm1 & 3) && (tb->tm_mon > 1) )
tmptm2++;/*
* Calculate elapsed days since base date (midnight, 1/1/70, UTC)
*
*
* 365 days for each elapsed year since 1970, plus one more day for
* each elapsed leap year. no danger of overflow because of the range
* check (above) on tmptm1.
*/
tmptm3 = (tmptm1 - _BASE_YEAR) * 365L + ((tmptm1 - 1L) >> 2)
- _LEAP_YEAR_ADJUST;/*
* elapsed days to current month (still no possible overflow)
*/
tmptm3 += tmptm2;/*
* elapsed days to current date. overflow is now possible.
*/
tmptm1 = tmptm3 + (tmptm2 = (__time32_t)(tb->tm_mday));
if ( ChkAdd(tmptm1, tmptm3, tmptm2) )
goto err_mktime;/***** HERE: tmptm1 holds number of elapsed days *****/
/*
* Calculate elapsed hours since base date
*/
tmptm2 = tmptm1 * 24L;
if ( ChkMul(tmptm2, tmptm1, 24L) )
goto err_mktime;tmptm1 = tmptm2 + (tmptm3 = (__time32_t)tb->tm_hour);
if ( ChkAdd(tmptm1, tmptm2, tmptm3) )
goto err_mktime;/***** HERE: tmptm1 holds number of elapsed hours *****/
/*
* Calculate elapsed minutes since base date
*/tmptm2 = tmptm1 * 60L;
if ( ChkMul(tmptm2, tmptm1, 60L) )
goto err_mktime;tmptm1 = tmptm2 + (tmptm3 = (__time32_t)tb->tm_min);
if ( ChkAdd(tmptm1, tmptm2, tmptm3) )
goto err_mktime;/***** HERE: tmptm1 holds number of elapsed minutes *****/
/*
* Calculate elapsed seconds since base date
*/tmptm2 = tmptm1 * 60L;
if ( ChkMul(tmptm2, tmptm1, 60L) )
goto err_mktime;tmptm1 = tmptm2 + (tmptm3 = (__time32_t)tb->tm_sec);
if ( ChkAdd(tmptm1, tmptm2, tmptm3) )
goto err_mktime;/***** HERE: tmptm1 holds number of elapsed seconds *****/
if ( ultflag ) {
/*
* Adjust for timezone. No need to check for overflow since
* localtime() will check its arg value
*/__tzset();
_ERRCHECK(_get_dstbias(&dstbias));
_ERRCHECK(_get_timezone(&timezone));tmptm1 += timezone;
/*
* Convert this second count back into a time block structure.
* If localtime returns NULL, return an error.
*/
if ( _localtime32_s(&tbtemp, &tmptm1) != 0 )
goto err_mktime;/*
* Now must compensate for DST. The ANSI rules are to use the
* passed-in tm_isdst flag if it is non-negative. Otherwise,
* compute if DST applies. Recall that tbtemp has the time without
* DST compensation, but has set tm_isdst correctly.
*/
if ( (tb->tm_isdst > 0) || ((tb->tm_isdst < 0) &&
(tbtemp.tm_isdst > 0)) ) {
tmptm1 += dstbias;
if ( _localtime32_s(&tbtemp, &tmptm1) != 0 )
goto err_mktime;
}}
else {
if ( _gmtime32_s(&tbtemp, &tmptm1) != 0 )
goto err_mktime;
}/***** HERE: tmptm1 holds number of elapsed seconds, adjusted *****/
/***** for local time if requested *****/*tb = tbtemp;
return (__time32_t)tmptm1;err_mktime:
/*
* All errors come to here
*/errno = EINVAL;
return (__time32_t)(-1);
}
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