Subversion Repositories Kolibri OS

/*

 * 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

 *                      Fixed bug in mday computations - 08/12/04, Alex Mogilnikov 

 *                      Fixed bug in __tzcalc_limits - 08/12/04, Alex Mogilnikov 

 *

 * 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 

#include 

#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 y;

  int yleap;

  _CONST int *ip;

   __tzinfo_type *tz = __gettzinfo ();

  /* 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)

    {

      long offset;

      int hours, mins, secs;

      TZ_LOCK;

      if (_daylight)

	{

	  if (y == tz->__tzyear || __tzcalc_limits (y))

	    res->tm_isdst = (tz->__tznorth

			     ? (*tim_p >= tz->__tzrule[0].change

				&& *tim_p < tz->__tzrule[1].change)

			     : (*tim_p >= tz->__tzrule[0].change

				|| *tim_p < tz->__tzrule[1].change));

	  else

	    res->tm_isdst = -1;

	}

      else

	res->tm_isdst = 0;

      offset = (res->tm_isdst == 1

		  ? tz->__tzrule[1].offset

		  : tz->__tzrule[0].offset);

      hours = (int) (offset / SECSPERHOUR);

      offset = offset % SECSPERHOUR;

      mins = (int) (offset / SECSPERMIN);

      secs = (int) (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];

	      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 = 364 + isleap(res->tm_year + 1900);

		}

	      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;

  __tzinfo_type *tz = __gettzinfo ();

  if (year < EPOCH_YEAR)

    return 0;

  tz->__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 (tz->__tzrule[i].ch == 'J') {

        /* The Julian day n (1 <= n <= 365). */

	days = year_days + tz->__tzrule[i].d +

		(isleap(year) && tz->__tzrule[i].d >= 60);

        /* Convert to yday */

        --days;

	} else if (tz->__tzrule[i].ch == 'D')

	days = year_days + tz->__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 < tz->__tzrule[i].m; ++j)

	    days += ip[j-1];

	  m_wday = (EPOCH_WDAY + days) % DAYSPERWEEK;

	  wday_diff = tz->__tzrule[i].d - m_wday;

	  if (wday_diff < 0)

	    wday_diff += DAYSPERWEEK;

	  m_day = (tz->__tzrule[i].n - 1) * DAYSPERWEEK + wday_diff;

	  while (m_day >= ip[j-1])

	    m_day -= DAYSPERWEEK;

	  days += m_day;

	}

      /* store the change-over time in GMT form by adding offset */

      tz->__tzrule[i].change = days * SECSPERDAY +

	      			tz->__tzrule[i].s + tz->__tzrule[i].offset;

    }

  tz->__tznorth = (tz->__tzrule[0].change < tz->__tzrule[1].change);

  return 1;

}