summaryrefslogtreecommitdiffstats
path: root/win/tclWinTime.c
blob: de0e3dd42810e131f8c9455e3c0024b374a57365 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
/* 
 * 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 1.4 1999/04/16 00:48:10 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(t, useGMT)
    TclpTime_t t;
    int useGMT;
{
    const time_t *tp = (const time_t *) t;
    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.
	 */

	if (*tp >= 0) {
	    return localtime(tp);
	}

	time = *tp - _timezone;
	
	/*
	 * 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;
}