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/******************************** -*- C -*- ****************************
*
* System specific implementation module.
*
* This module contains implementations of various operating system
* specific routines. This module should encapsulate most (or all)
* of these calls so that the rest of the code is portable.
*
*
***********************************************************************/
/***********************************************************************
*
* Copyright 1988,89,90,91,92,94,95,99,2000,2001,2002,2003,2006,2007,2008,2009
* Free Software Foundation, Inc.
* Written by Steve Byrne.
*
* This file is part of GNU Smalltalk.
*
* GNU Smalltalk is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2, or (at your option) any later
* version.
*
* Linking GNU Smalltalk statically or dynamically with other modules is
* making a combined work based on GNU Smalltalk. Thus, the terms and
* conditions of the GNU General Public License cover the whole
* combination.
*
* In addition, as a special exception, the Free Software Foundation
* give you permission to combine GNU Smalltalk with free software
* programs or libraries that are released under the GNU LGPL and with
* independent programs running under the GNU Smalltalk virtual machine.
*
* You may copy and distribute such a system following the terms of the
* GNU GPL for GNU Smalltalk and the licenses of the other code
* concerned, provided that you include the source code of that other
* code when and as the GNU GPL requires distribution of source code.
*
* Note that people who make modified versions of GNU Smalltalk are not
* obligated to grant this special exception for their modified
* versions; it is their choice whether to do so. The GNU General
* Public License gives permission to release a modified version without
* this exception; this exception also makes it possible to release a
* modified version which carries forward this exception.
*
* GNU Smalltalk is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* GNU Smalltalk; see the file COPYING. If not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
***********************************************************************/
#include "gstpriv.h"
#ifdef HAVE_UTIME_H
# include <utime.h>
#endif
#ifdef HAVE_SYS_TIMES_H
# include <sys/times.h>
#endif
#ifdef HAVE_SYS_TIMEB_H
#include <sys/timeb.h>
#endif
#define TM_YEAR_BASE 1900
/* Yield A - B, measured in seconds.
This function is copied from the GNU C Library. */
static int
tm_diff (struct tm *a,
struct tm *b)
{
/* Compute intervening leap days correctly even if year is negative.
Take care to avoid int overflow in leap day calculations, but it's
OK to assume that A and B are close to each other. */
int a4 = (a->tm_year >> 2) + (TM_YEAR_BASE >> 2) - !(a->tm_year & 3);
int b4 = (b->tm_year >> 2) + (TM_YEAR_BASE >> 2) - !(b->tm_year & 3);
int a100 = a4 / 25 - (a4 % 25 < 0);
int b100 = b4 / 25 - (b4 % 25 < 0);
int a400 = a100 >> 2;
int b400 = b100 >> 2;
int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
int years = a->tm_year - b->tm_year;
int days = (365 * years + intervening_leap_days
+ (a->tm_yday - b->tm_yday));
return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
+ (a->tm_min - b->tm_min)) + (a->tm_sec - b->tm_sec));
}
time_t
_gst_adjust_time_zone (time_t t)
{
struct tm save_tm, *decoded_time;
time_t bias;
#ifdef LOCALTIME_CACHE
tzset ();
#endif
decoded_time = localtime (&t);
save_tm = *decoded_time;
decoded_time = gmtime (&t);
bias = tm_diff (&save_tm, decoded_time);
return (t + bias);
}
long
_gst_current_time_zone_bias (void)
{
time_t now;
long bias;
struct tm save_tm, *decoded_time;
time (&now);
#ifdef LOCALTIME_CACHE
tzset ();
#endif
decoded_time = localtime (&now);
save_tm = *decoded_time;
decoded_time = gmtime (&now);
bias = tm_diff (&save_tm, decoded_time);
return (bias);
}
time_t
_gst_get_time (void)
{
time_t now;
time (&now);
return (_gst_adjust_time_zone (now));
}
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