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cde/src/lib/libast/tm/tminit.c

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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2012 AT&T Intellectual Property *
* Copyright (c) 2020-2021 Contributors to ksh 93u+m *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <glenn.s.fowler@gmail.com> *
* David Korn <dgkorn@gmail.com> *
* Phong Vo <phongvo@gmail.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* time conversion support
*/
#include <tm.h>
#include <ctype.h>
#include <namval.h>
#include "FEATURE/tmlib"
#ifndef tzname
# if defined(__DYNAMIC__)
# undef _dat_tzname
# define tzname __DYNAMIC__(tzname)
# else
# if !_dat_tzname
# if _dat__tzname
# undef _dat_tzname
# define _dat_tzname 1
# define tzname _tzname
# endif
# endif
# endif
# if _dat_tzname && !defined(tzname)
extern char* tzname[];
# endif
#endif
#define TM_type (-1)
static const Namval_t options[] =
{
"adjust", TM_ADJUST,
"format", TM_DEFAULT,
"leap", TM_LEAP,
"subsecond", TM_SUBSECOND,
"type", TM_type,
"utc", TM_UTC,
0, 0
};
/*
* 2007-03-19 move tm_info from _tm_info_ to (*_tm_infop_)
* to allow future Tm_info_t growth
* by 2009 _tm_info_ can be static
*/
#if _BLD_ast && defined(__EXPORT__)
#define extern extern __EXPORT__
#endif
extern Tm_info_t _tm_info_;
#undef extern
Tm_info_t _tm_info_ = { 0 };
__EXTERN__(Tm_info_t, _tm_info_);
__EXTERN__(Tm_info_t*, _tm_infop_);
Tm_info_t* _tm_infop_ = &_tm_info_;
#if _tzset_environ
static char TZ[256];
static char* TE[2];
struct tm*
_tm_localtime(const time_t* t)
{
struct tm* r;
char* e;
char** v = environ;
if (TZ[0])
{
if (!environ || !*environ)
environ = TE;
else
e = environ[0];
environ[0] = TZ;
}
r = localtime(t);
if (TZ[0])
{
if (environ != v)
environ = v;
else
environ[0] = e;
}
return r;
}
#endif
/*
* return minutes west of GMT for local time clock
*
* isdst will point to non-zero if DST is in effect
* this routine also kicks in the local initialization
*/
static int
tzwest(time_t* clock, int* isdst)
{
register struct tm* tp;
register int n;
register int m;
int h;
time_t epoch;
/*
* convert to GMT assuming local time
*/
if (!(tp = gmtime(clock)))
{
/*
* some systems return 0 for negative time_t
*/
epoch = 0;
clock = &epoch;
tp = gmtime(clock);
}
n = tp->tm_yday;
h = tp->tm_hour;
m = tp->tm_min;
/*
* tmlocaltime() handles DST and GMT offset
*/
tp = tmlocaltime(clock);
if (n = tp->tm_yday - n)
{
if (n > 1)
n = -1;
else if (n < -1)
n = 1;
}
*isdst = tp->tm_isdst;
return (h - tp->tm_hour - n * 24) * 60 + m - tp->tm_min;
}
/*
* stropt() option handler
*/
static int
tmopt(void* a, const void* p, int n, const char* v)
{
Tm_zone_t* zp;
NoP(a);
if (p)
switch (((Namval_t*)p)->value)
{
case TM_DEFAULT:
tm_info.deformat = (n && (n = strlen(v)) > 0 && (n < 2 || v[n-2] != '%' || v[n-1] != '?')) ? strdup(v) : tm_info.format[TM_DEFAULT];
break;
case TM_type:
tm_info.local->type = (n && *v) ? ((zp = tmtype(v, NiL)) ? zp->type : strdup(v)) : 0;
break;
default:
if (n)
tm_info.flags |= ((Namval_t*)p)->value;
else
tm_info.flags &= ~((Namval_t*)p)->value;
break;
}
return 0;
}
/*
* initialize the local timezone
*/
static void
tmlocal(void)
{
register Tm_zone_t* zp;
register int n;
register char* s;
register char* e;
int i;
int m;
int isdst;
char* t;
struct tm* tp;
time_t now;
char buf[16];
static Tm_zone_t local;
#if _tzset_environ
{
char** v = environ;
if (s = getenv("TZ"))
{
sfsprintf(TZ, sizeof(TZ), "TZ=%s", s);
if (!environ || !*environ)
environ = TE;
else
e = environ[0];
environ[0] = TZ;
}
else
{
TZ[0] = 0;
e = 0;
}
#endif
#if _lib_tzset
tzset();
#endif
#if _tzset_environ
if (environ != v)
environ = v;
else if (e)
environ[0] = e;
}
#endif
tmlocale();
/*
* tm_info.local
*/
tm_info.zone = tm_info.local = &local;
time(&now);
n = tzwest(&now, &isdst);
/*
* compute local DST offset by roaming
* through the last 12 months until tzwest() changes
*/
for (i = 0; i < 12; i++)
{
now -= 31 * 24 * 60 * 60;
if ((m = tzwest(&now, &isdst)) != n)
{
if (!isdst)
{
isdst = n;
n = m;
m = isdst;
}
m -= n;
break;
}
}
local.west = n;
local.dst = m;
/*
* now get the time zone names
*/
#if _dat_tzname
if (tzname[0])
{
/*
* POSIX
*/
local.standard = strdup(tzname[0]);
local.daylight = strdup(tzname[1]);
}
else
#endif
if ((s = getenv("TZNAME")) && *s && (s = strdup(s)))
{
/*
* BSD
*/
local.standard = s;
if (s = strchr(s, ','))
*s++ = 0;
else
s = "";
local.daylight = s;
}
else if ((s = getenv("TZ")) && *s && *s != ':' && (s = strdup(s)))
{
/*
* POSIX style but skipped by tmlocaltime()
*/
local.standard = s;
if (*++s && *++s && *++s)
{
*s++ = 0;
tmgoff(s, &t, 0);
for (s = t; isalpha(*t); t++);
*t = 0;
}
else
s = "";
local.daylight = s;
}
else
{
/*
* tm_data.zone table lookup
*/
t = 0;
for (zp = tm_data.zone; zp->standard; zp++)
{
if (zp->type)
t = zp->type;
if (zp->west == n && zp->dst == m)
{
local.type = t;
local.standard = zp->standard;
if (!(s = zp->daylight))
{
e = (s = buf) + sizeof(buf);
s = tmpoff(s, e - s, zp->standard, 0, 0);
if (s < e - 1)
{
*s++ = ' ';
tmpoff(s, e - s, tm_info.format[TM_DT], m, TM_DST);
}
s = strdup(buf);
}
local.daylight = s;
break;
}
}
if (!zp->standard)
{
/*
* not in the table
*/
e = (s = buf) + sizeof(buf);
s = tmpoff(s, e - s, tm_info.format[TM_UT], n, 0);
local.standard = strdup(buf);
if (s < e - 1)
{
*s++ = ' ';
tmpoff(s, e - s, tm_info.format[TM_UT], m, TM_DST);
local.daylight = strdup(buf);
}
}
}
if (!*local.standard && !local.west && !local.dst && (s = getenv("TZ")))
{
if ((zp = tmzone(s, &t, NiL, NiL)) && !*t)
{
local.standard = strdup(zp->standard);
if (zp->daylight)
local.daylight = strdup(zp->daylight);
local.west = zp->west;
local.dst = zp->dst;
}
else
local.standard = strdup(s);
if (!local.standard)
local.standard = "";
if (!local.daylight)
local.daylight = "";
}
/*
* set the options
*/
stropt(getenv("TM_OPTIONS"), options, sizeof(*options), tmopt, NiL);
/*
* the time zone type is probably related to the locale
*/
if (!local.type)
{
s = local.standard;
t = 0;
for (zp = tm_data.zone; zp->standard; zp++)
{
if (zp->type)
t = zp->type;
if (tmword(s, NiL, zp->standard, NiL, 0))
{
local.type = t;
break;
}
}
}
/*
* tm_info.flags
*/
if (!(tm_info.flags & TM_ADJUST))
{
now = (time_t)78811200; /* Jun 30 1972 23:59:60 */
tp = tmlocaltime(&now);
if (tp->tm_sec != 60)
tm_info.flags |= TM_ADJUST;
}
if (!(tm_info.flags & TM_UTC))
{
s = local.standard;
zp = tm_data.zone;
if (local.daylight)
zp++;
for (; !zp->type && zp->standard; zp++)
if (tmword(s, NiL, zp->standard, NiL, 0))
{
tm_info.flags |= TM_UTC;
break;
}
}
}
/*
* initialize tm data
*/
void
tminit(register Tm_zone_t* zp)
{
static uint32_t serial = ~(uint32_t)0;
if (serial != ast.env_serial)
{
serial = ast.env_serial;
if (tm_info.local)
{
memset(tm_info.local, 0, sizeof(*tm_info.local));
tm_info.local = 0;
}
}
if (!tm_info.local)
tmlocal();
if (!zp)
zp = tm_info.local;
tm_info.zone = zp;
}
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