374 lines
7.8 KiB
C
374 lines
7.8 KiB
C
/*
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* tclWinTime.c --
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*
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* Contains Windows specific versions of Tcl functions that
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* obtain time values from the operating system.
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*
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* Copyright 1995 by Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*
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* SCCS: @(#) tclWinTime.c 1.6 97/04/14 17:25:56
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*/
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#include "tclInt.h"
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#include "tclPort.h"
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#define SECSPERDAY (60L * 60L * 24L)
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#define SECSPERYEAR (SECSPERDAY * 365L)
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#define SECSPER4YEAR (SECSPERYEAR * 4L + SECSPERDAY)
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/*
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* The following arrays contain the day of year for the last day of
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* each month, where index 1 is January.
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*/
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static int normalDays[] = {
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-1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364
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};
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static int leapDays[] = {
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-1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
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};
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/*
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* Declarations for functions defined later in this file.
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*/
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static struct tm * ComputeGMT _ANSI_ARGS_((const time_t *tp));
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetSeconds --
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*
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* This procedure returns the number of seconds from the epoch.
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* On most Unix systems the epoch is Midnight Jan 1, 1970 GMT.
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*
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* Results:
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* Number of seconds from the epoch.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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unsigned long
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TclpGetSeconds()
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{
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return (unsigned long) time((time_t *) NULL);
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetClicks --
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*
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* This procedure returns a value that represents the highest
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* resolution clock available on the system. There are no
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* guarantees on what the resolution will be. In Tcl we will
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* call this value a "click". The start time is also system
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* dependant.
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*
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* Results:
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* Number of clicks from some start time.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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unsigned long
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TclpGetClicks()
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{
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return GetTickCount();
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetTimeZone --
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*
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* Determines the current timezone. The method varies wildly
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* between different Platform implementations, so its hidden in
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* this function.
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*
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* Results:
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* Minutes west of GMT.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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int
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TclpGetTimeZone (currentTime)
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unsigned long currentTime;
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{
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int timeZone;
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tzset();
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timeZone = _timezone / 60;
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return timeZone;
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetTime --
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*
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* Gets the current system time in seconds and microseconds
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* since the beginning of the epoch: 00:00 UCT, January 1, 1970.
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*
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* Results:
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* Returns the current time in timePtr.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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void
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TclpGetTime(timePtr)
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Tcl_Time *timePtr; /* Location to store time information. */
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{
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struct timeb t;
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ftime(&t);
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timePtr->sec = t.time;
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timePtr->usec = t.millitm * 1000;
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetTZName --
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*
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* Gets the current timezone string.
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*
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* Results:
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* Returns a pointer to a static string, or NULL on failure.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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char *
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TclpGetTZName()
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{
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tzset();
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if (_daylight && _tzname[1] != NULL) {
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return _tzname[1];
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} else {
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return _tzname[0];
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}
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclpGetDate --
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*
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* This function converts between seconds and struct tm. If
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* useGMT is true, then the returned date will be in Greenwich
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* Mean Time (GMT). Otherwise, it will be in the local time zone.
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*
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* Results:
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* Returns a static tm structure.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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struct tm *
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TclpGetDate(tp, useGMT)
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const time_t *tp;
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int useGMT;
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{
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struct tm *tmPtr;
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long time;
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if (!useGMT) {
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tzset();
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/*
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* If we are in the valid range, let the C run-time library
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* handle it. Otherwise we need to fake it. Note that this
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* algorithm ignores daylight savings time before the epoch.
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*/
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time = *tp - _timezone;
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if (time >= 0) {
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return localtime(tp);
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}
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/*
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* If we aren't near to overflowing the long, just add the bias and
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* use the normal calculation. Otherwise we will need to adjust
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* the result at the end.
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*/
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if (*tp < (LONG_MAX - 2 * SECSPERDAY)
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&& *tp > (LONG_MIN + 2 * SECSPERDAY)) {
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tmPtr = ComputeGMT(&time);
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} else {
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tmPtr = ComputeGMT(tp);
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tzset();
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/*
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* Add the bias directly to the tm structure to avoid overflow.
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* Propagate seconds overflow into minutes, hours and days.
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*/
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time = tmPtr->tm_sec - _timezone;
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tmPtr->tm_sec = (int)(time % 60);
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if (tmPtr->tm_sec < 0) {
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tmPtr->tm_sec += 60;
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time -= 60;
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}
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time = tmPtr->tm_min + time/60;
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tmPtr->tm_min = (int)(time % 60);
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if (tmPtr->tm_min < 0) {
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tmPtr->tm_min += 60;
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time -= 60;
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}
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time = tmPtr->tm_hour + time/60;
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tmPtr->tm_hour = (int)(time % 24);
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if (tmPtr->tm_hour < 0) {
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tmPtr->tm_hour += 24;
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time -= 24;
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}
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time /= 24;
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tmPtr->tm_mday += time;
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tmPtr->tm_yday += time;
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tmPtr->tm_wday = (tmPtr->tm_wday + time) % 7;
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}
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} else {
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tmPtr = ComputeGMT(tp);
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}
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return tmPtr;
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}
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/*
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*----------------------------------------------------------------------
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*
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* ComputeGMT --
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*
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* This function computes GMT given the number of seconds since
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* the epoch (midnight Jan 1 1970).
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*
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* Results:
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* Returns a statically allocated struct tm.
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*
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* Side effects:
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* Updates the values of the static struct tm.
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*
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*----------------------------------------------------------------------
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*/
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static struct tm *
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ComputeGMT(tp)
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const time_t *tp;
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{
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static struct tm tm; /* This should be allocated per thread.*/
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long tmp, rem;
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int isLeap;
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int *days;
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/*
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* Compute the 4 year span containing the specified time.
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*/
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tmp = *tp / SECSPER4YEAR;
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rem = *tp % SECSPER4YEAR;
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/*
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* Correct for weird mod semantics so the remainder is always positive.
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*/
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if (rem < 0) {
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tmp--;
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rem += SECSPER4YEAR;
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}
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/*
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* Compute the year after 1900 by taking the 4 year span and adjusting
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* for the remainder. This works because 2000 is a leap year, and
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* 1900/2100 are out of the range.
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*/
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tmp = (tmp * 4) + 70;
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isLeap = 0;
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if (rem >= SECSPERYEAR) { /* 1971, etc. */
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tmp++;
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rem -= SECSPERYEAR;
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if (rem >= SECSPERYEAR) { /* 1972, etc. */
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tmp++;
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rem -= SECSPERYEAR;
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if (rem >= SECSPERYEAR + SECSPERDAY) { /* 1973, etc. */
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tmp++;
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rem -= SECSPERYEAR + SECSPERDAY;
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} else {
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isLeap = 1;
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}
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}
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}
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tm.tm_year = tmp;
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/*
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* Compute the day of year and leave the seconds in the current day in
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* the remainder.
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*/
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tm.tm_yday = rem / SECSPERDAY;
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rem %= SECSPERDAY;
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/*
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* Compute the time of day.
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*/
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tm.tm_hour = rem / 3600;
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rem %= 3600;
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tm.tm_min = rem / 60;
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tm.tm_sec = rem % 60;
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/*
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* Compute the month and day of month.
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*/
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days = (isLeap) ? leapDays : normalDays;
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for (tmp = 1; days[tmp] < tm.tm_yday; tmp++) {
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}
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tm.tm_mon = --tmp;
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tm.tm_mday = tm.tm_yday - days[tmp];
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/*
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* Compute day of week. Epoch started on a Thursday.
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*/
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tm.tm_wday = (*tp / SECSPERDAY) + 4;
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if ((*tp % SECSPERDAY) < 0) {
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tm.tm_wday--;
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}
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tm.tm_wday %= 7;
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if (tm.tm_wday < 0) {
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tm.tm_wday += 7;
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}
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return &tm;
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}
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