/*
* tclWinTime.c --
*
* Contains Windows specific versions of Tcl functions that
* obtain time values from the operating system.
*
* Copyright 1995-1998 by Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tclWinTime.c,v 1.1.2.2 1998/09/24 23:59:54 stanton Exp $
*/
#include "tclWinInt.h"
#define SECSPERDAY (60L * 60L * 24L)
#define SECSPERYEAR (SECSPERDAY * 365L)
#define SECSPER4YEAR (SECSPERYEAR * 4L + SECSPERDAY)
/*
* The following arrays contain the day of year for the last day of
* each month, where index 1 is January.
*/
static int normalDays[] = {
-1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364
};
static int leapDays[] = {
-1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
};
typedef struct ThreadSpecificData {
char tzName[64]; /* Time zone name */
struct tm tm; /* time information */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;
/*
* Declarations for functions defined later in this file.
*/
static struct tm * ComputeGMT _ANSI_ARGS_((const time_t *tp));
/*
*----------------------------------------------------------------------
*
* TclpGetSeconds --
*
* This procedure returns the number of seconds from the epoch.
* On most Unix systems the epoch is Midnight Jan 1, 1970 GMT.
*
* Results:
* Number of seconds from the epoch.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
unsigned long
TclpGetSeconds()
{
return (unsigned long) time((time_t *) NULL);
}
/*
*----------------------------------------------------------------------
*
* TclpGetClicks --
*
* This procedure returns a value that represents the highest
* resolution clock available on the system. There are no
* guarantees on what the resolution will be. In Tcl we will
* call this value a "click". The start time is also system
* dependant.
*
* Results:
* Number of clicks from some start time.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
unsigned long
TclpGetClicks()
{
return GetTickCount();
}
/*
*----------------------------------------------------------------------
*
* TclpGetTimeZone --
*
* Determines the current timezone. The method varies wildly
* between different Platform implementations, so its hidden in
* this function.
*
* Results:
* Minutes west of GMT.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int
TclpGetTimeZone (currentTime)
unsigned long currentTime;
{
int timeZone;
tzset();
timeZone = _timezone / 60;
return timeZone;
}
/*
*----------------------------------------------------------------------
*
* TclpGetTime --
*
* Gets the current system time in seconds and microseconds
* since the beginning of the epoch: 00:00 UCT, January 1, 1970.
*
* Results:
* Returns the current time in timePtr.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TclpGetTime(timePtr)
Tcl_Time *timePtr; /* Location to store time information. */
{
struct timeb t;
ftime(&t);
timePtr->sec = t.time;
timePtr->usec = t.millitm * 1000;
}
/*
*----------------------------------------------------------------------
*
* TclpGetTZName --
*
* Gets the current timezone string.
*
* Results:
* Returns a pointer to a static string, or NULL on failure.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
char *
TclpGetTZName(int dst)
{
int len;
char *zone, *p;
TIME_ZONE_INFORMATION tz;
Tcl_Encoding encoding;
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
char *name = tsdPtr->tzName;
/*
* tzset() under Borland doesn't seem to set up tzname[] at all.
* tzset() under MSVC has the following weird observed behavior:
* First time we call "clock format [clock seconds] -format %Z -gmt 1"
* we get "GMT", but on all subsequent calls we get the current time
* zone string, even though env(TZ) is GMT and the variable _timezone
* is 0.
*/
name[0] = '\0';
zone = getenv("TZ");
if (zone != NULL) {
/*
* TZ is of form "NST-4:30NDT", where "NST" would be the
* name of the standard time zone for this area, "-4:30" is
* the offset from GMT in hours, and "NDT is the name of
* the daylight savings time zone in this area. The offset
* and DST strings are optional.
*/
len = strlen(zone);
if (len > 3) {
len = 3;
}
if (dst != 0) {
/*
* Skip the offset string and get the DST string.
*/
p = zone + len;
p += strspn(p, "+-:0123456789");
if (*p != '\0') {
zone = p;
len = strlen(zone);
if (len > 3) {
len = 3;
}
}
}
Tcl_ExternalToUtf(NULL, NULL, zone, len, 0, NULL, name,
sizeof(tsdPtr->tzName), NULL, NULL, NULL);
}
if ((name[0] == '\0')
&& (GetTimeZoneInformation(&tz) != TIME_ZONE_ID_UNKNOWN)) {
encoding = Tcl_GetEncoding(NULL, "unicode");
Tcl_ExternalToUtf(NULL, encoding,
(char *) ((dst) ? tz.DaylightName : tz.StandardName), -1,
0, NULL, name, sizeof(tsdPtr->tzName), NULL, NULL, NULL);
Tcl_FreeEncoding(encoding);
}
if (name[0] == '\0') {
return "%Z";
}
return name;
}
/*
*----------------------------------------------------------------------
*
* TclpGetDate --
*
* This function converts between seconds and struct tm. If
* useGMT is true, then the returned date will be in Greenwich
* Mean Time (GMT). Otherwise, it will be in the local time zone.
*
* Results:
* Returns a static tm structure.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
struct tm *
TclpGetDate(tp, useGMT)
const time_t *tp;
int useGMT;
{
struct tm *tmPtr;
long time;
if (!useGMT) {
tzset();
/*
* If we are in the valid range, let the C run-time library
* handle it. Otherwise we need to fake it. Note that this
* algorithm ignores daylight savings time before the epoch.
*/
time = *tp - _timezone;
if (time >= 0) {
return localtime(tp);
}
/*
* If we aren't near to overflowing the long, just add the bias and
* use the normal calculation. Otherwise we will need to adjust
* the result at the end.
*/
if (*tp < (LONG_MAX - 2 * SECSPERDAY)
&& *tp > (LONG_MIN + 2 * SECSPERDAY)) {
tmPtr = ComputeGMT(&time);
} else {
tmPtr = ComputeGMT(tp);
tzset();
/*
* Add the bias directly to the tm structure to avoid overflow.
* Propagate seconds overflow into minutes, hours and days.
*/
time = tmPtr->tm_sec - _timezone;
tmPtr->tm_sec = (int)(time % 60);
if (tmPtr->tm_sec < 0) {
tmPtr->tm_sec += 60;
time -= 60;
}
time = tmPtr->tm_min + time/60;
tmPtr->tm_min = (int)(time % 60);
if (tmPtr->tm_min < 0) {
tmPtr->tm_min += 60;
time -= 60;
}
time = tmPtr->tm_hour + time/60;
tmPtr->tm_hour = (int)(time % 24);
if (tmPtr->tm_hour < 0) {
tmPtr->tm_hour += 24;
time -= 24;
}
time /= 24;
tmPtr->tm_mday += time;
tmPtr->tm_yday += time;
tmPtr->tm_wday = (tmPtr->tm_wday + time) % 7;
}
} else {
tmPtr = ComputeGMT(tp);
}
return tmPtr;
}
/*
*----------------------------------------------------------------------
*
* ComputeGMT --
*
* This function computes GMT given the number of seconds since
* the epoch (midnight Jan 1 1970).
*
* Results:
* Returns a (per thread) statically allocated struct tm.
*
* Side effects:
* Updates the values of the static struct tm.
*
*----------------------------------------------------------------------
*/
static struct tm *
ComputeGMT(tp)
const time_t *tp;
{
struct tm *tmPtr;
long tmp, rem;
int isLeap;
int *days;
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
tmPtr = &tsdPtr->tm;
/*
* Compute the 4 year span containing the specified time.
*/
tmp = *tp / SECSPER4YEAR;
rem = *tp % SECSPER4YEAR;
/*
* Correct for weird mod semantics so the remainder is always positive.
*/
if (rem < 0) {
tmp--;
rem += SECSPER4YEAR;
}
/*
* Compute the year after 1900 by taking the 4 year span and adjusting
* for the remainder. This works because 2000 is a leap year, and
* 1900/2100 are out of the range.
*/
tmp = (tmp * 4) + 70;
isLeap = 0;
if (rem >= SECSPERYEAR) { /* 1971, etc. */
tmp++;
rem -= SECSPERYEAR;
if (rem >= SECSPERYEAR) { /* 1972, etc. */
tmp++;
rem -= SECSPERYEAR;
if (rem >= SECSPERYEAR + SECSPERDAY) { /* 1973, etc. */
tmp++;
rem -= SECSPERYEAR + SECSPERDAY;
} else {
isLeap = 1;
}
}
}
tmPtr->tm_year = tmp;
/*
* Compute the day of year and leave the seconds in the current day in
* the remainder.
*/
tmPtr->tm_yday = rem / SECSPERDAY;
rem %= SECSPERDAY;
/*
* Compute the time of day.
*/
tmPtr->tm_hour = rem / 3600;
rem %= 3600;
tmPtr->tm_min = rem / 60;
tmPtr->tm_sec = rem % 60;
/*
* Compute the month and day of month.
*/
days = (isLeap) ? leapDays : normalDays;
for (tmp = 1; days[tmp] < tmPtr->tm_yday; tmp++) {
}
tmPtr->tm_mon = --tmp;
tmPtr->tm_mday = tmPtr->tm_yday - days[tmp];
/*
* Compute day of week. Epoch started on a Thursday.
*/
tmPtr->tm_wday = (*tp / SECSPERDAY) + 4;
if ((*tp % SECSPERDAY) < 0) {
tmPtr->tm_wday--;
}
tmPtr->tm_wday %= 7;
if (tmPtr->tm_wday < 0) {
tmPtr->tm_wday += 7;
}
return tmPtr;
}