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/*
* mktm_r.c
* Original Author: Adapted from tzcode maintained by Arthur David Olson.
* Modifications: Changed to mktm_r and added __tzcalc_limits - 04/10/02, Jeff Johnston
*
* Converts the calendar time pointed to by tim_p into a broken-down time
* expressed as local time. Returns a pointer to a structure containing the
* broken-down time.
*/
#include <stdlib.h>
#include <time.h>
#include "local.h"
static _CONST int mon_lengths[2][MONSPERYEAR] = {
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
{31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
} ;
static _CONST int year_lengths[2] = {
365,
366
} ;
struct tm *
_DEFUN (_mktm_r, (tim_p, res, is_gmtime),
_CONST time_t * tim_p _AND
struct tm *res _AND
int is_gmtime)
{
long days, rem;
time_t lcltime;
int i;
int y;
int yleap;
_CONST int *ip;
/* base decision about std/dst time on current time */
lcltime = *tim_p;
days = ((long)lcltime) / SECSPERDAY;
rem = ((long)lcltime) % SECSPERDAY;
while (rem < 0)
{
rem += SECSPERDAY;
--days;
}
while (rem >= SECSPERDAY)
{
rem -= SECSPERDAY;
++days;
}
/* compute hour, min, and sec */
res->tm_hour = (int) (rem / SECSPERHOUR);
rem %= SECSPERHOUR;
res->tm_min = (int) (rem / SECSPERMIN);
res->tm_sec = (int) (rem % SECSPERMIN);
/* compute day of week */
if ((res->tm_wday = ((EPOCH_WDAY + days) % DAYSPERWEEK)) < 0)
res->tm_wday += DAYSPERWEEK;
/* compute year & day of year */
y = EPOCH_YEAR;
if (days >= 0)
{
for (;;)
{
yleap = isleap(y);
if (days < year_lengths[yleap])
break;
y++;
days -= year_lengths[yleap];
}
}
else
{
do
{
--y;
yleap = isleap(y);
days += year_lengths[yleap];
} while (days < 0);
}
res->tm_year = y - YEAR_BASE;
res->tm_yday = days;
ip = mon_lengths[yleap];
for (res->tm_mon = 0; days >= ip[res->tm_mon]; ++res->tm_mon)
days -= ip[res->tm_mon];
res->tm_mday = days + 1;
if (!is_gmtime)
{
int offset;
int hours, mins, secs;
TZ_LOCK;
if (_daylight)
{
if (y == __tzyear || __tzcalc_limits (y))
res->tm_isdst = (__tznorth
? (*tim_p >= __tzrule[0].change && *tim_p < __tzrule[1].change)
: (*tim_p >= __tzrule[0].change || *tim_p < __tzrule[1].change));
else
res->tm_isdst = -1;
}
else
res->tm_isdst = 0;
offset = (res->tm_isdst == 1 ? __tzrule[1].offset : __tzrule[0].offset);
hours = offset / SECSPERHOUR;
offset = offset % SECSPERHOUR;
mins = offset / SECSPERMIN;
secs = offset % SECSPERMIN;
res->tm_sec -= secs;
res->tm_min -= mins;
res->tm_hour -= hours;
if (res->tm_sec >= SECSPERMIN)
{
res->tm_min += 1;
res->tm_sec -= SECSPERMIN;
}
else if (res->tm_sec < 0)
{
res->tm_min -= 1;
res->tm_sec += SECSPERMIN;
}
if (res->tm_min >= MINSPERHOUR)
{
res->tm_hour += 1;
res->tm_min -= MINSPERHOUR;
}
else if (res->tm_min < 0)
{
res->tm_hour -= 1;
res->tm_min += MINSPERHOUR;
}
if (res->tm_hour >= HOURSPERDAY)
{
++res->tm_yday;
++res->tm_wday;
if (res->tm_wday > 6)
res->tm_wday = 0;
++res->tm_mday;
res->tm_hour -= HOURSPERDAY;
if (res->tm_mday >= ip[res->tm_mon])
{
res->tm_mday -= ip[res->tm_mon] - 1;
res->tm_mon += 1;
if (res->tm_mon == 12)
{
res->tm_mon = 0;
res->tm_year += 1;
res->tm_yday = 0;
}
}
}
else if (res->tm_hour < 0)
{
res->tm_yday -= 1;
res->tm_wday -= 1;
if (res->tm_wday < 0)
res->tm_wday = 6;
res->tm_mday -= 1;
res->tm_hour += 24;
if (res->tm_mday == 0)
{
res->tm_mon -= 1;
if (res->tm_mon < 0)
{
res->tm_mon = 11;
res->tm_year -= 1;
res->tm_yday = 365 + isleap(res->tm_year);
}
res->tm_mday = ip[res->tm_mon];
}
}
TZ_UNLOCK;
}
else
res->tm_isdst = 0;
return (res);
}
int
_DEFUN (__tzcalc_limits, (year),
int year)
{
int days, year_days, years;
int i, j;
if (year < EPOCH_YEAR)
return 0;
__tzyear = year;
years = (year - EPOCH_YEAR);
year_days = years * 365 +
(years - 1 + EPOCH_YEARS_SINCE_LEAP) / 4 - (years - 1 + EPOCH_YEARS_SINCE_CENTURY) / 100 +
(years - 1 + EPOCH_YEARS_SINCE_LEAP_CENTURY) / 400;
for (i = 0; i < 2; ++i)
{
if (__tzrule[i].ch == 'J')
days = year_days + __tzrule[i].d + (isleap(year) && __tzrule[i].d >= 60);
else if (__tzrule[i].ch == 'D')
days = year_days + __tzrule[i].d;
else
{
int yleap = isleap(year);
int m_day, m_wday, wday_diff;
_CONST int *ip = mon_lengths[yleap];
days = year_days;
for (j = 1; j < __tzrule[i].m; ++j)
days += ip[j-1];
m_wday = (EPOCH_WDAY + days) % DAYSPERWEEK;
wday_diff = __tzrule[i].d - m_wday;
if (wday_diff < 0)
wday_diff += DAYSPERWEEK;
m_day = (__tzrule[i].n - 1) * DAYSPERWEEK + wday_diff;
while (m_day >= ip[j])
m_day -= DAYSPERWEEK;
days += m_day;
}
/* store the change-over time in GMT form by adding offset */
__tzrule[i].change = days * SECSPERDAY + __tzrule[i].s + __tzrule[i].offset;
}
__tznorth = (__tzrule[0].change < __tzrule[1].change);
return 1;
}
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