146 lines
3.9 KiB
C++
146 lines
3.9 KiB
C++
// natVMTimeZone.cc -- Native side of VMTimeZone class.
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/* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006
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Free Software Foundation
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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#include <config.h>
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#include <platform.h>
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#include <gcj/cni.h>
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#include <jvm.h>
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#include <java/util/VMTimeZone.h>
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#include <java/lang/Character.h>
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#include <java/lang/Integer.h>
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#include <stdio.h>
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#if TIME_WITH_SYS_TIME
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# include <sys/time.h>
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# include <time.h>
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#else
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# if HAVE_SYS_TIME_H
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# include <sys/time.h>
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# else
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# include <time.h>
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# endif
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#endif
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#include <string.h>
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/**
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* This method returns a time zone id string which is in the form
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* (standard zone name) or (standard zone name)(GMT offset) or
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* (standard zone name)(GMT offset)(daylight time zone name). The
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* GMT offset can be in seconds, or where it is evenly divisible by
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* 3600, then it can be in hours. The offset must be the time to
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* add to the local time to get GMT. If a offset is given and the
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* time zone observes daylight saving then the (daylight time zone
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* name) must also be given (otherwise it is assumed the time zone
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* does not observe any daylight savings).
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* <p>
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* The result of this method is given to getDefaultTimeZone(String)
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* which tries to map the time zone id to a known TimeZone. See
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* that method on how the returned String is mapped to a real
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* TimeZone object.
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*/
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jstring
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java::util::VMTimeZone::getSystemTimeZoneId()
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{
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struct tm tim;
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#if !defined(HAVE_LOCALTIME_R) || !defined(_POSIX_PTHREAD_SEMANTICS)
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struct tm *lt_tim;
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#endif
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#ifdef HAVE_TM_ZONE
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int month;
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#endif
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time_t current_time;
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long tzoffset;
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const char *tz1, *tz2;
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char *tzid;
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time(¤t_time);
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#if defined(HAVE_LOCALTIME_R) && defined(_POSIX_PTHREAD_SEMANTICS)
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localtime_r(¤t_time, &tim);
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#else
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/* Fall back on non-thread safe localtime. */
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lt_tim = localtime(¤t_time);
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memcpy(&tim, lt_tim, sizeof (struct tm));
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#endif
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mktime(&tim);
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#ifdef HAVE_TM_ZONE
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/* We will cycle through the months to make sure we hit dst. */
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month = tim.tm_mon;
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tz1 = tz2 = NULL;
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while (tz1 == NULL || tz2 == NULL)
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{
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if (tim.tm_isdst > 0)
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tz2 = tim.tm_zone;
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else if (tz1 == NULL)
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{
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tz1 = tim.tm_zone;
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month = tim.tm_mon;
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}
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if (tz1 == NULL || tz2 == NULL)
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{
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tim.tm_mon++;
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tim.tm_mon %= 12;
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}
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if (tim.tm_mon == month && tz2 == NULL)
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tz2 = "";
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else
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mktime(&tim);
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}
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/* We want to make sure the tm struct we use later on is not dst. */
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tim.tm_mon = month;
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mktime(&tim);
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#elif defined (HAVE_TZNAME)
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/* If dst is never used, tzname[1] is the empty string. */
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tzset();
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tz1 = tzname[0];
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tz2 = tzname[1];
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#else
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/* Some targets have no concept of timezones. Assume GMT without dst. */
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tz1 = "GMT";
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tz2 = "";
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#endif
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#ifdef STRUCT_TM_HAS_GMTOFF
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/* tm_gmtoff is the number of seconds that you must add to GMT to get
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local time, we need the number of seconds to add to the local time
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to get GMT. */
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tzoffset = -1L * tim.tm_gmtoff;
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#elif HAVE_UNDERSCORE_TIMEZONE
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tzoffset = _timezone;
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#elif HAVE_TIMEZONE
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/* timezone is secs WEST of UTC. */
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tzoffset = timezone;
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#else
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/* FIXME: there must be another global if neither tm_gmtoff nor timezone
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is available, esp. if tzname is valid.
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Richard Earnshaw <rearnsha@arm.com> has suggested using difftime to
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calculate between gmtime and localtime (and accounting for possible
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daylight savings time) as an alternative. */
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tzoffset = 0L;
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#endif
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if ((tzoffset % 3600) == 0)
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tzoffset = tzoffset / 3600;
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tzid = (char*) _Jv_Malloc (strlen(tz1) + strlen(tz2) + 6);
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sprintf(tzid, "%s%ld%s", tz1, tzoffset, tz2);
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jstring retval = JvNewStringUTF (tzid);
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_Jv_Free (tzid);
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return retval;
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}
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