/****************************************************************************
*
* Open Watcom Project
*
* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
* ========================================================================
*
* This file contains Original Code and/or Modifications of Original
* Code as defined in and that are subject to the Sybase Open Watcom
* Public License version 1.0 (the 'License'). You may not use this file
* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
* provided with the Original Code and Modifications, and is also
* available at www.sybase.com/developer/opensource.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
* NON-INFRINGEMENT. Please see the License for the specific language
* governing rights and limitations under the License.
*
* ========================================================================
*
* Description: Platform independent tzset() implementation.
*
****************************************************************************/
#include "variety.h"
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <time.h>
#include "rtdata.h"
#include "timedata.h"
#include "exitwmsg.h"
#include "_time.h"
/*
* TZSET - sets the values of the variables 'timezone', 'daylight'
* and 'tzname' according to the setting of the environment
* variable "TZ". The "TZ" variable has the format
* :characters
* or
* <std><offset>[<dst>[<offset>]][,<start>[/<time>],<end>[/<time>]]]
*/
//#define TZNAME_MAX 128 /* defined in <limits.h> */
struct tm __start_dst = { /* start of daylight savings */
0, 0, 2, /* M4.1.0/02:00:00 default */
1, 3, 0, /* i.e., 1st Sunday of Apr */
0, 0, 0
};
struct tm __end_dst = { /* end of daylight savings */
0, 0, 1, /* M10.5.0/02:00:00 default */
5, 9, 0, /* i.e., last Sunday of Oct */
0, 0, 0 /* note that this is specified*/
}; /* in terms of EST */
/* i.e. 02:00 EDT == 01:00 EST*/
static char stzone[TZNAME_MAX + 1] = "EST"; /* place to store names */
static char dtzone[TZNAME_MAX + 1] = "EDT"; /* place to store names */
_WCRTLINKD char *tzname[2] = { stzone, dtzone };
_WCRTLINKD long timezone = 5L * 60L * 60L; /* seconds from GMT */
_WCRTLINKD int daylight = 1; /* d.s.t. indicator */
int __dst_adjust = 60 * 60; /* daylight adjustment */
static struct {
unsigned cache_OS_TZ : 1;
unsigned have_OS_TZ : 1;
} tzFlag = { 1, 0 };
int __DontCacheOSTZ( void )
/*************************/
{
int old_flag;
old_flag = tzFlag.cache_OS_TZ;
tzFlag.cache_OS_TZ = 0;
tzFlag.have_OS_TZ = 0;
return( old_flag );
}
int __CacheOSTZ( void )
/*********************/
{
int old_flag;
old_flag = tzFlag.cache_OS_TZ;
tzFlag.cache_OS_TZ = 1;
tzFlag.have_OS_TZ = 0;
return( old_flag );
}
static char *parse_time( char *tz, int *val )
/*******************************************/
{
int value;
value = 0;
while( *tz >= '0' && *tz <= '9' ) {
value = value * 10 + *tz - '0';
++tz;
}
*val = value;
return( tz );
}
static char *parse_offset( char *tz, char *name, long *offset )
/*************************************************************/
{
int hours;
int minutes;
int seconds;
int neg;
int len;
char ch;
char const *tzstart;
if( *tz == ':' )
tz++;
/* remember where time zone name string begins */
tzstart = tz;
/* parse time zone name (should be 3 or more characters) */
/* examples: PST8, EDT+6, Central Standard Time+7:00:00 */
for( ;; ) {
ch = *tz;
if( ch == '\0' )
break;
if( ch == ',' )
break;
if( ch == '-' )
break;
if( ch == '+' )
break;
if( ch >= '0' && ch <= '9' )
break;
++tz;
}
len = tz - tzstart;
if( len > TZNAME_MAX )
len = TZNAME_MAX;
memcpy( name
, tzstart
, ( size_t ) len
); name[len] = '\0';
neg = 0;
if( ch == '-' ) {
neg = 1;
++tz;
} else if( ch == '+' )
++tz;
ch = *tz;
if( ch >= '0' && ch <= '9' ) {
hours = minutes = seconds = 0;
tz = parse_time( tz, &hours );
if( *tz == ':' ) {
tz = parse_time( tz + 1, &minutes );
if( *tz == ':' )
tz = parse_time( tz + 1, &seconds );
}
*offset = seconds + ( ( minutes + ( hours * 60 ) ) * 60L );
if( neg )
*offset = -*offset;
}
return( tz );
}
static char *parse_rule( char *tz, struct tm *timeptr )
/*****************************************************/
{
int date_form;
int days;
int hours;
int minutes;
int seconds;
date_form = -1; /* n 0-365 */
if( *tz == 'J' ) { /* Jn 1-365 (no leap days) */
date_form = 1;
tz++;
}
if( *tz == 'M' ) { /* Mm.n.d n'th day of month */
date_form = 0;
tz++;
}
timeptr->tm_isdst = date_form;
tz = parse_time( tz, &days );
if( date_form != 0 )
timeptr->tm_yday = days;
else {
timeptr->tm_mon = days - 1; /* 1-12 for M form */
if( *tz == '.' ) {
tz = parse_time( tz + 1, &days ); /* 1-5 for M form */
timeptr->tm_mday = days;
if( *tz == '.' ) {
tz = parse_time( tz + 1, &days );/* 0-6 for M form */
timeptr->tm_wday = days;
}
}
timeptr->tm_yday = 0;
}
hours = 2;
minutes = seconds = 0;
if( *tz == '/' ) {
tz = parse_time( tz + 1, &hours );
if( *tz == ':' ) {
tz = parse_time( tz + 1, &minutes );
if( *tz == ':' )
tz = parse_time( tz + 1, &seconds );
}
}
timeptr->tm_sec = seconds;
timeptr->tm_min = minutes;
timeptr->tm_hour = hours;
return( tz );
}
void __parse_tz( char * tz )
/**************************/
{
long dayzone;
_RWD_daylight = 0;
tz = parse_offset( tz, stzone, &_RWD_timezone );
if( *tz == '\0' ) {
dtzone[0] = '\0';
return;
}
_RWD_daylight = 1;
dayzone = _RWD_timezone - ( 60*60 ); /* 16-aug-91 */
tz = parse_offset( tz, dtzone, &dayzone );
_RWD_dst_adjust = _RWD_timezone - dayzone;
/* parse daylight changing rules */
if( *tz == ',' )
tz = parse_rule( tz + 1, &__start_dst );
if( *tz == ',' ) {
tz = parse_rule( tz + 1, &__end_dst );
/* convert rule to be in terms of Standard Time */
/* rather than Daylight Time */
__end_dst.tm_hour -= _RWD_dst_adjust / 3600;
__end_dst.tm_min -= ( _RWD_dst_adjust / 60 ) % 60;
__end_dst.tm_sec -= _RWD_dst_adjust % 60;
}
}
static int tryOSTimeZone( const char *tz )
/****************************************/
{
if( tz == NULL ) {
/* calling OS can be expensive; many programs don't care */
if( tzFlag.cache_OS_TZ && tzFlag.have_OS_TZ )
return( 1 );
/* Assume that even if we end up not getting the TZ from OS,
we won't have any better luck if we try later. */
tzFlag.have_OS_TZ = 1;
} else {
tzFlag.have_OS_TZ = 0;
return( 0 );
}
// assume Eastern (North America) time zone
_RWD_timezone = 5L * 60L * 60L;
_RWD_dst_adjust = 60L * 60L;
return( 1 );
}
_WCRTLINK void tzset( void )
/**************************/
{
#ifndef __NETWARE__
char *tz;
if( !tryOSTimeZone( tz ) && tz != NULL )
__parse_tz( tz );
#endif
}