Commit e3120ab5 authored by Jim Blandy's avatar Jim Blandy

Some time-handling patches from Paul Eggert:

	* editfns.c (Fcurrent_time_zone): Take an optional argument specifying
	what (absolute) time should be used to determine the current time zone.
	Yield just offset and name of time zone, including DST correction.
	Yield time zone offset in seconds, not minutes.
	(lisp_time_argument, difftm): New functions.
	(Fcurrent_time_string): Use lisp_time_argument.
	* systime.h (EMACS_CURRENT_TIME_ZONE, EMACS_GET_TZ_OFFSET,
	EMACS_GET_TZ_NAMES): Remove.
	* config.h.in: Add HAVE_TM_ZONE.
parent facb137b
......@@ -86,6 +86,7 @@ and this notice must be preserved on all copies. */
#undef HAVE_GETTIMEOFDAY
#undef HAVE_GETHOSTNAME
#undef HAVE_DUP2
#undef HAVE_TM_ZONE
#undef TM_IN_SYS_TIME
#undef STDC_HEADERS
#undef TIME_WITH_SYS_TIME
......
......@@ -541,6 +541,27 @@ resolution finer than a second.")
}
static int
lisp_time_argument (specified_time, result)
Lisp_Object specified_time;
time_t *result;
{
if (NILP (specified_time))
return time (result) != -1;
else
{
Lisp_Object high, low;
high = Fcar (specified_time);
CHECK_NUMBER (high, 0);
low = Fcdr (specified_time);
if (XTYPE (low) == Lisp_Cons)
low = Fcar (low);
CHECK_NUMBER (low, 0);
*result = (XINT (high) << 16) + (XINT (low) & 0xffff);
return *result >> 16 == XINT (high);
}
}
DEFUN ("current-time-string", Fcurrent_time_string, Scurrent_time_string, 0, 1, 0,
"Return the current time, as a human-readable string.\n\
Programs can use this function to decode a time,\n\
......@@ -556,24 +577,12 @@ and from `file-attributes'.")
(specified_time)
Lisp_Object specified_time;
{
long value;
time_t value;
char buf[30];
register char *tem;
if (NILP (specified_time))
value = time ((long *) 0);
else
{
Lisp_Object high, low;
high = Fcar (specified_time);
CHECK_NUMBER (high, 0);
low = Fcdr (specified_time);
if (XTYPE (low) == Lisp_Cons)
low = Fcar (low);
CHECK_NUMBER (low, 0);
value = ((XINT (high) << 16) + (XINT (low) & 0xffff));
}
if (! lisp_time_argument (specified_time, &value))
value = -1;
tem = (char *) ctime (&value);
strncpy (buf, tem, 24);
......@@ -582,42 +591,79 @@ and from `file-attributes'.")
return build_string (buf);
}
DEFUN ("current-time-zone", Fcurrent_time_zone, Scurrent_time_zone, 0, 0, 0,
"Return the offset, savings state, and names for the current time zone.\n\
This returns a list of the form (OFFSET SAVINGS-FLAG STANDARD SAVINGS).\n\
OFFSET is an integer specifying how many minutes east of Greenwich the\n\
current time zone is located. A negative value means west of\n\
Greenwich. Note that this describes the standard time; if daylight\n\
savings time is in effect, it does not affect this value.\n\
SAVINGS-FLAG is non-nil iff daylight savings time or some other sort\n\
of seasonal time adjustment is in effect.\n\
STANDARD is a string giving the name of the time zone when no seasonal\n\
time adjustment is in effect.\n\
SAVINGS is a string giving the name of the time zone when there is a\n\
seasonal time adjustment in effect.\n\
If the local area does not use a seasonal time adjustment,\n\
SAVINGS-FLAG is always nil, and STANDARD and SAVINGS are equal.\n\
#define TM_YEAR_ORIGIN 1900
/* Yield A - B, measured in seconds. */
static long
difftm(a, b)
struct tm *a, *b;
{
int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
return
(
(
(
/* difference in day of year */
a->tm_yday - b->tm_yday
/* + intervening leap days */
+ ((ay >> 2) - (by >> 2))
- (ay/100 - by/100)
+ ((ay/100 >> 2) - (by/100 >> 2))
/* + difference in years * 365 */
+ (long)(ay-by) * 365
)*24 + (a->tm_hour - b->tm_hour)
)*60 + (a->tm_min - b->tm_min)
)*60 + (a->tm_sec - b->tm_sec);
}
DEFUN ("current-time-zone", Fcurrent_time_zone, Scurrent_time_zone, 0, 1, 0,
"Return the offset and name for the local time zone.\n\
This returns a list of the form (OFFSET NAME).\n\
OFFSET is an integer number of seconds ahead of UTC (east of Greenwich).\n\
A negative value means west of Greenwich.\n\
NAME is a string giving the name of the time zone.\n\
If an argument is given, it specifies when the time zone offset is determined\n\
instead of using the current time. The argument should have the form:\n\
(HIGH . LOW)\n\
or the form:\n\
(HIGH LOW . IGNORED).\n\
Thus, you can use times obtained from `current-time'\n\
and from `file-attributes'.\n\
\n\
Some operating systems cannot provide all this information to Emacs;\n\
in this case, current-time-zone will return a list containing nil for\n\
the data it can't find.")
()
(specified_time)
Lisp_Object specified_time;
{
#ifdef EMACS_CURRENT_TIME_ZONE
int offset, savings_flag;
char standard[11];
char savings[11];
EMACS_CURRENT_TIME_ZONE (&offset, &savings_flag, standard, savings);
return Fcons (make_number (offset),
Fcons ((savings_flag ? Qt : Qnil),
Fcons (build_string (standard),
Fcons (build_string (savings),
Qnil))));
#else
return Fmake_list (4, Qnil);
time_t value;
struct tm *t;
if (lisp_time_argument (specified_time, &value)
&& (t = gmtime(&value)) != 0)
{
struct tm gmt = *t; /* Make a copy, in case localtime modifies *t. */
long offset;
char *s, buf[6];
t = localtime(&value);
offset = difftm(t, &gmt);
s = 0;
#ifdef HAVE_TM_ZONE
if (t->tm_zone)
s = t->tm_zone;
#endif
if (!s)
{
/* No local time zone name is available; use "+-NNNN" instead. */
long am = (offset < 0 ? -offset : offset) / 60;
sprintf (buf, "%c%02d%02d", (offset < 0 ? '-' : '+'), am/60, am%60);
s = buf;
}
return Fcons (make_number (offset), Fcons (build_string (s), Qnil));
}
else
return Fmake_list (2, Qnil);
}
......
......@@ -146,114 +146,3 @@ extern long timezone;
}
#endif /* ! defined (USE_UTIME) */
/* EMACS_CURRENT_TIME_ZONE (int *OFFSET, int *SAVINGS_FLAG,
char *STANDARD_ABBR, char *SAVINGS_ABBR);
expands to a statement which stores information about the current
time zone in its arguments.
*OFFSET is set to the number of minutes EAST of Greenwich at which
the site's time zone is located. This should describe the offset
to standard time only; if some sort of daylight savings time is in
effect, that should not affect this value. Note that the tm_gmtoff
member of the struct tm returned by localtime is adjusted for
daylight savings, so you don't want to use localtime to set
*OFFSET; gettimeofday does the right thing.
*SAVINGS_FLAG is set to 1 if some sort of daylight savings time is
currently in effect, or 0 if no seasonal adjustment is currently
active.
*STANDARD_ABBR points to an array of at least 10 characters, which
should be set to the standard abbreviation for the time zone name
when daylight savings time is not active. For example, EDT would
be appropriate for the Eastern time zone of the USA.
*SAVINGS_ABBR points to an array of at least 10 characters, which
should be set to the standard abbreviation for the time zone name
when daylight savings time is active. For example, EST would be
appropriate for the Eastern time zone of the USA.
If the operating system cannot provide all this information, then
this macro will not be defined. */
/* The operating system configuration file can define
EMACS_CURRENT_TIME_ZONE. If not, we'll take a shot at it here. */
#ifndef EMACS_CURRENT_TIME_ZONE
/* System V derivatives have a timezone global variable. */
#if defined(USG) || defined(VMS)
#define EMACS_GET_TZ_OFFSET(offset) \
do { \
tzset (); \
*(offset) = timezone; \
} while (0)
#endif
/* If we have timeval, then we have gettimeofday; that's half the battle. */
#if defined (HAVE_TIMEVAL) && !defined (EMACS_GET_TZ_OFFSET)
#define EMACS_GET_TZ_OFFSET(offset) \
do { \
struct timeval dummy; \
struct timezone zoneinfo; \
\
gettimeofday (&dummy, &zoneinfo); \
*(offset) = -zoneinfo.tz_minuteswest; \
} while (0)
#endif /* ! defined (HAVE_TIMEVAL) */
/* The following sane systems have a tzname array. The timezone function
is a stupid idea; timezone names can only be determined geographically,
not by Greenwich offset. */
#if defined (ultrix) || defined (hpux) || defined (_AIX) || defined (USG) || defined(VMS)
#define EMACS_GET_TZ_NAMES(standard, savings) \
do { \
extern char *tzname[2]; \
strcpy ((standard), tzname[0]); \
strcpy ((savings), tzname[1]); \
} while (0)
#else /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
/* If we are running SunOS, Mt. Xinu BSD, or MACH 2.5, these systems have a
timezone function. */
#if (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun) || defined (NeXT)
#define EMACS_GET_TZ_NAMES(standard, savings) \
do { \
struct timeval dummy; \
struct timezone zoneinfo; \
extern char *timezone (); \
\
gettimeofday (&dummy, &zoneinfo); \
strcpy ((standard), timezone (zoneinfo.tz_minuteswest, 0)); \
strcpy ((savings), timezone (zoneinfo.tz_minuteswest, 1)); \
} while (0)
#endif /* ! (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun) */
#endif /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
/* If we can get all the information we need, let's define the macro! */
#if defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES)
#define EMACS_CURRENT_TIME_ZONE(offset, savings_flag, standard, savings)\
do { \
EMACS_TIME t; \
long secs; \
struct tm *tmp; \
\
EMACS_GET_TIME (t); \
secs = EMACS_SECS (t); \
tmp = localtime (&secs); \
*(savings_flag) = tmp->tm_isdst; \
\
EMACS_GET_TZ_OFFSET (offset); \
EMACS_GET_TZ_NAMES (standard, savings); \
} while (0)
#endif /* ! defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES) */
#endif /* EMACS_CURRENT_TIME_ZONE */
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