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1/*
2** 2003 October 31
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This file contains the C functions that implement date and time
13** functions for SQLite.
14**
15** There is only one exported symbol in this file - the function
16** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
17** All other code has file scope.
18**
19** $Id: date.c,v 1.73 2007/09/12 17:01:45 danielk1977 Exp $
20**
21** SQLite processes all times and dates as Julian Day numbers. The
22** dates and times are stored as the number of days since noon
23** in Greenwich on November 24, 4714 B.C. according to the Gregorian
24** calendar system.
25**
26** 1970-01-01 00:00:00 is JD 2440587.5
27** 2000-01-01 00:00:00 is JD 2451544.5
28**
29** This implemention requires years to be expressed as a 4-digit number
30** which means that only dates between 0000-01-01 and 9999-12-31 can
31** be represented, even though julian day numbers allow a much wider
32** range of dates.
33**
34** The Gregorian calendar system is used for all dates and times,
35** even those that predate the Gregorian calendar. Historians usually
36** use the Julian calendar for dates prior to 1582-10-15 and for some
37** dates afterwards, depending on locale. Beware of this difference.
38**
39** The conversion algorithms are implemented based on descriptions
40** in the following text:
41**
42** Jean Meeus
43** Astronomical Algorithms, 2nd Edition, 1998
44** ISBM 0-943396-61-1
45** Willmann-Bell, Inc
46** Richmond, Virginia (USA)
47*/
48#include "sqliteInt.h"
49#include <ctype.h>
50#include <stdlib.h>
51#include <assert.h>
52#include <time.h>
53
54#ifndef SQLITE_OMIT_DATETIME_FUNCS
55
56/*
57** A structure for holding a single date and time.
58*/
59typedef struct DateTime DateTime;
60struct DateTime {
61 double rJD; /* The julian day number */
62 int Y, M, D; /* Year, month, and day */
63 int h, m; /* Hour and minutes */
64 int tz; /* Timezone offset in minutes */
65 double s; /* Seconds */
66 char validYMD; /* True if Y,M,D are valid */
67 char validHMS; /* True if h,m,s are valid */
68 char validJD; /* True if rJD is valid */
69 char validTZ; /* True if tz is valid */
70};
71
72
73/*
74** Convert zDate into one or more integers. Additional arguments
75** come in groups of 5 as follows:
76**
77** N number of digits in the integer
78** min minimum allowed value of the integer
79** max maximum allowed value of the integer
80** nextC first character after the integer
81** pVal where to write the integers value.
82**
83** Conversions continue until one with nextC==0 is encountered.
84** The function returns the number of successful conversions.
85*/
86static int getDigits(const char *zDate, ...){
87 va_list ap;
88 int val;
89 int N;
90 int min;
91 int max;
92 int nextC;
93 int *pVal;
94 int cnt = 0;
95 va_start(ap, zDate);
96 do{
97 N = va_arg(ap, int);
98 min = va_arg(ap, int);
99 max = va_arg(ap, int);
100 nextC = va_arg(ap, int);
101 pVal = va_arg(ap, int*);
102 val = 0;
103 while( N-- ){
104 if( !isdigit(*(u8*)zDate) ){
105 goto end_getDigits;
106 }
107 val = val*10 + *zDate - '0';
108 zDate++;
109 }
110 if( val<min || val>max || (nextC!=0 && nextC!=*zDate) ){
111 goto end_getDigits;
112 }
113 *pVal = val;
114 zDate++;
115 cnt++;
116 }while( nextC );
117end_getDigits:
118 va_end(ap);
119 return cnt;
120}
121
122/*
123** Read text from z[] and convert into a floating point number. Return
124** the number of digits converted.
125*/
126#define getValue sqlite3AtoF
127
128/*
129** Parse a timezone extension on the end of a date-time.
130** The extension is of the form:
131**
132** (+/-)HH:MM
133**
134** If the parse is successful, write the number of minutes
135** of change in *pnMin and return 0. If a parser error occurs,
136** return 0.
137**
138** A missing specifier is not considered an error.
139*/
140static int parseTimezone(const char *zDate, DateTime *p){
141 int sgn = 0;
142 int nHr, nMn;
143 while( isspace(*(u8*)zDate) ){ zDate++; }
144 p->tz = 0;
145 if( *zDate=='-' ){
146 sgn = -1;
147 }else if( *zDate=='+' ){
148 sgn = +1;
149 }else{
150 return *zDate!=0;
151 }
152 zDate++;
153 if( getDigits(zDate, 2, 0, 14, ':', &nHr, 2, 0, 59, 0, &nMn)!=2 ){
154 return 1;
155 }
156 zDate += 5;
157 p->tz = sgn*(nMn + nHr*60);
158 while( isspace(*(u8*)zDate) ){ zDate++; }
159 return *zDate!=0;
160}
161
162/*
163** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF.
164** The HH, MM, and SS must each be exactly 2 digits. The
165** fractional seconds FFFF can be one or more digits.
166**
167** Return 1 if there is a parsing error and 0 on success.
168*/
169static int parseHhMmSs(const char *zDate, DateTime *p){
170 int h, m, s;
171 double ms = 0.0;
172 if( getDigits(zDate, 2, 0, 24, ':', &h, 2, 0, 59, 0, &m)!=2 ){
173 return 1;
174 }
175 zDate += 5;
176 if( *zDate==':' ){
177 zDate++;
178 if( getDigits(zDate, 2, 0, 59, 0, &s)!=1 ){
179 return 1;
180 }
181 zDate += 2;
182 if( *zDate=='.' && isdigit((u8)zDate[1]) ){
183 double rScale = 1.0;
184 zDate++;
185 while( isdigit(*(u8*)zDate) ){
186 ms = ms*10.0 + *zDate - '0';
187 rScale *= 10.0;
188 zDate++;
189 }
190 ms /= rScale;
191 }
192 }else{
193 s = 0;
194 }
195 p->validJD = 0;
196 p->validHMS = 1;
197 p->h = h;
198 p->m = m;
199 p->s = s + ms;
200 if( parseTimezone(zDate, p) ) return 1;
201 p->validTZ = p->tz!=0;
202 return 0;
203}
204
205/*
206** Convert from YYYY-MM-DD HH:MM:SS to julian day. We always assume
207** that the YYYY-MM-DD is according to the Gregorian calendar.
208**
209** Reference: Meeus page 61
210*/
211static void computeJD(DateTime *p){
212 int Y, M, D, A, B, X1, X2;
213
214 if( p->validJD ) return;
215 if( p->validYMD ){
216 Y = p->Y;
217 M = p->M;
218 D = p->D;
219 }else{
220 Y = 2000; /* If no YMD specified, assume 2000-Jan-01 */
221 M = 1;
222 D = 1;
223 }
224 if( M<=2 ){
225 Y--;
226 M += 12;
227 }
228 A = Y/100;
229 B = 2 - A + (A/4);
230 X1 = 365.25*(Y+4716);
231 X2 = 30.6001*(M+1);
232 p->rJD = X1 + X2 + D + B - 1524.5;
233 p->validJD = 1;
234 if( p->validHMS ){
235 p->rJD += (p->h*3600.0 + p->m*60.0 + p->s)/86400.0;
236 if( p->validTZ ){
237 p->rJD -= p->tz*60/86400.0;
238 p->validYMD = 0;
239 p->validHMS = 0;
240 p->validTZ = 0;
241 }
242 }
243}
244
245/*
246** Parse dates of the form
247**
248** YYYY-MM-DD HH:MM:SS.FFF
249** YYYY-MM-DD HH:MM:SS
250** YYYY-MM-DD HH:MM
251** YYYY-MM-DD
252**
253** Write the result into the DateTime structure and return 0
254** on success and 1 if the input string is not a well-formed
255** date.
256*/
257static int parseYyyyMmDd(const char *zDate, DateTime *p){
258 int Y, M, D, neg;
259
260 if( zDate[0]=='-' ){
261 zDate++;
262 neg = 1;
263 }else{
264 neg = 0;
265 }
266 if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)!=3 ){
267 return 1;
268 }
269 zDate += 10;
270 while( isspace(*(u8*)zDate) || 'T'==*(u8*)zDate ){ zDate++; }
271 if( parseHhMmSs(zDate, p)==0 ){
272 /* We got the time */
273 }else if( *zDate==0 ){
274 p->validHMS = 0;
275 }else{
276 return 1;
277 }
278 p->validJD = 0;
279 p->validYMD = 1;
280 p->Y = neg ? -Y : Y;
281 p->M = M;
282 p->D = D;
283 if( p->validTZ ){
284 computeJD(p);
285 }
286 return 0;
287}
288
289/*
290** Attempt to parse the given string into a Julian Day Number. Return
291** the number of errors.
292**
293** The following are acceptable forms for the input string:
294**
295** YYYY-MM-DD HH:MM:SS.FFF +/-HH:MM
296** DDDD.DD
297** now
298**
299** In the first form, the +/-HH:MM is always optional. The fractional
300** seconds extension (the ".FFF") is optional. The seconds portion
301** (":SS.FFF") is option. The year and date can be omitted as long
302** as there is a time string. The time string can be omitted as long
303** as there is a year and date.
304*/
305static int parseDateOrTime(
306 sqlite3_context *context,
307 const char *zDate,
308 DateTime *p
309){
310 memset(p, 0, sizeof(*p));
311 if( parseYyyyMmDd(zDate,p)==0 ){
312 return 0;
313 }else if( parseHhMmSs(zDate, p)==0 ){
314 return 0;
315 }else if( sqlite3StrICmp(zDate,"now")==0){
316 double r;
317 sqlite3OsCurrentTime((sqlite3_vfs *)sqlite3_user_data(context), &r);
318 p->rJD = r;
319 p->validJD = 1;
320 return 0;
321 }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){
322 getValue(zDate, &p->rJD);
323 p->validJD = 1;
324 return 0;
325 }
326 return 1;
327}
328
329/*
330** Compute the Year, Month, and Day from the julian day number.
331*/
332static void computeYMD(DateTime *p){
333 int Z, A, B, C, D, E, X1;
334 if( p->validYMD ) return;
335 if( !p->validJD ){
336 p->Y = 2000;
337 p->M = 1;
338 p->D = 1;
339 }else{
340 Z = p->rJD + 0.5;
341 A = (Z - 1867216.25)/36524.25;
342 A = Z + 1 + A - (A/4);
343 B = A + 1524;
344 C = (B - 122.1)/365.25;
345 D = 365.25*C;
346 E = (B-D)/30.6001;
347 X1 = 30.6001*E;
348 p->D = B - D - X1;
349 p->M = E<14 ? E-1 : E-13;
350 p->Y = p->M>2 ? C - 4716 : C - 4715;
351 }
352 p->validYMD = 1;
353}
354
355/*
356** Compute the Hour, Minute, and Seconds from the julian day number.
357*/
358static void computeHMS(DateTime *p){
359 int Z, s;
360 if( p->validHMS ) return;
361 computeJD(p);
362 Z = p->rJD + 0.5;
363 s = (p->rJD + 0.5 - Z)*86400000.0 + 0.5;
364 p->s = 0.001*s;
365 s = p->s;
366 p->s -= s;
367 p->h = s/3600;
368 s -= p->h*3600;
369 p->m = s/60;
370 p->s += s - p->m*60;
371 p->validHMS = 1;
372}
373
374/*
375** Compute both YMD and HMS
376*/
377static void computeYMD_HMS(DateTime *p){
378 computeYMD(p);
379 computeHMS(p);
380}
381
382/*
383** Clear the YMD and HMS and the TZ
384*/
385static void clearYMD_HMS_TZ(DateTime *p){
386 p->validYMD = 0;
387 p->validHMS = 0;
388 p->validTZ = 0;
389}
390
391/*
392** Compute the difference (in days) between localtime and UTC (a.k.a. GMT)
393** for the time value p where p is in UTC.
394*/
395static double localtimeOffset(DateTime *p){
396 DateTime x, y;
397 time_t t;
398 x = *p;
399 computeYMD_HMS(&x);
400 if( x.Y<1971 || x.Y>=2038 ){
401 x.Y = 2000;
402 x.M = 1;
403 x.D = 1;
404 x.h = 0;
405 x.m = 0;
406 x.s = 0.0;
407 } else {
408 int s = x.s + 0.5;
409 x.s = s;
410 }
411 x.tz = 0;
412 x.validJD = 0;
413 computeJD(&x);
414 t = (x.rJD-2440587.5)*86400.0 + 0.5;
415#ifdef HAVE_LOCALTIME_R
416 {
417 struct tm sLocal;
418 localtime_r(&t, &sLocal);
419 y.Y = sLocal.tm_year + 1900;
420 y.M = sLocal.tm_mon + 1;
421 y.D = sLocal.tm_mday;
422 y.h = sLocal.tm_hour;
423 y.m = sLocal.tm_min;
424 y.s = sLocal.tm_sec;
425 }
426#else
427 {
428 struct tm *pTm;
429 sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
430 pTm = localtime(&t);
431 y.Y = pTm->tm_year + 1900;
432 y.M = pTm->tm_mon + 1;
433 y.D = pTm->tm_mday;
434 y.h = pTm->tm_hour;
435 y.m = pTm->tm_min;
436 y.s = pTm->tm_sec;
437 sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
438 }
439#endif
440 y.validYMD = 1;
441 y.validHMS = 1;
442 y.validJD = 0;
443 y.validTZ = 0;
444 computeJD(&y);
445 return y.rJD - x.rJD;
446}
447
448/*
449** Process a modifier to a date-time stamp. The modifiers are
450** as follows:
451**
452** NNN days
453** NNN hours
454** NNN minutes
455** NNN.NNNN seconds
456** NNN months
457** NNN years
458** start of month
459** start of year
460** start of week
461** start of day
462** weekday N
463** unixepoch
464** localtime
465** utc
466**
467** Return 0 on success and 1 if there is any kind of error.
468*/
469static int parseModifier(const char *zMod, DateTime *p){
470 int rc = 1;
471 int n;
472 double r;
473 char *z, zBuf[30];
474 z = zBuf;
475 for(n=0; n<sizeof(zBuf)-1 && zMod[n]; n++){
476 z[n] = tolower(zMod[n]);
477 }
478 z[n] = 0;
479 switch( z[0] ){
480 case 'l': {
481 /* localtime
482 **
483 ** Assuming the current time value is UTC (a.k.a. GMT), shift it to
484 ** show local time.
485 */
486 if( strcmp(z, "localtime")==0 ){
487 computeJD(p);
488 p->rJD += localtimeOffset(p);
489 clearYMD_HMS_TZ(p);
490 rc = 0;
491 }
492 break;
493 }
494 case 'u': {
495 /*
496 ** unixepoch
497 **
498 ** Treat the current value of p->rJD as the number of
499 ** seconds since 1970. Convert to a real julian day number.
500 */
501 if( strcmp(z, "unixepoch")==0 && p->validJD ){
502 p->rJD = p->rJD/86400.0 + 2440587.5;
503 clearYMD_HMS_TZ(p);
504 rc = 0;
505 }else if( strcmp(z, "utc")==0 ){
506 double c1;
507 computeJD(p);
508 c1 = localtimeOffset(p);
509 p->rJD -= c1;
510 clearYMD_HMS_TZ(p);
511 p->rJD += c1 - localtimeOffset(p);
512 rc = 0;
513 }
514 break;
515 }
516 case 'w': {
517 /*
518 ** weekday N
519 **
520 ** Move the date to the same time on the next occurrence of
521 ** weekday N where 0==Sunday, 1==Monday, and so forth. If the
522 ** date is already on the appropriate weekday, this is a no-op.
523 */
524 if( strncmp(z, "weekday ", 8)==0 && getValue(&z[8],&r)>0
525 && (n=r)==r && n>=0 && r<7 ){
526 int Z;
527 computeYMD_HMS(p);
528 p->validTZ = 0;
529 p->validJD = 0;
530 computeJD(p);
531 Z = p->rJD + 1.5;
532 Z %= 7;
533 if( Z>n ) Z -= 7;
534 p->rJD += n - Z;
535 clearYMD_HMS_TZ(p);
536 rc = 0;
537 }
538 break;
539 }
540 case 's': {
541 /*
542 ** start of TTTTT
543 **
544 ** Move the date backwards to the beginning of the current day,
545 ** or month or year.
546 */
547 if( strncmp(z, "start of ", 9)!=0 ) break;
548 z += 9;
549 computeYMD(p);
550 p->validHMS = 1;
551 p->h = p->m = 0;
552 p->s = 0.0;
553 p->validTZ = 0;
554 p->validJD = 0;
555 if( strcmp(z,"month")==0 ){
556 p->D = 1;
557 rc = 0;
558 }else if( strcmp(z,"year")==0 ){
559 computeYMD(p);
560 p->M = 1;
561 p->D = 1;
562 rc = 0;
563 }else if( strcmp(z,"day")==0 ){
564 rc = 0;
565 }
566 break;
567 }
568 case '+':
569 case '-':
570 case '0':
571 case '1':
572 case '2':
573 case '3':
574 case '4':
575 case '5':
576 case '6':
577 case '7':
578 case '8':
579 case '9': {
580 n = getValue(z, &r);
581 assert( n>=1 );
582 if( z[n]==':' ){
583 /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
584 ** specified number of hours, minutes, seconds, and fractional seconds
585 ** to the time. The ".FFF" may be omitted. The ":SS.FFF" may be
586 ** omitted.
587 */
588 const char *z2 = z;
589 DateTime tx;
590 int day;
591 if( !isdigit(*(u8*)z2) ) z2++;
592 memset(&tx, 0, sizeof(tx));
593 if( parseHhMmSs(z2, &tx) ) break;
594 computeJD(&tx);
595 tx.rJD -= 0.5;
596 day = (int)tx.rJD;
597 tx.rJD -= day;
598 if( z[0]=='-' ) tx.rJD = -tx.rJD;
599 computeJD(p);
600 clearYMD_HMS_TZ(p);
601 p->rJD += tx.rJD;
602 rc = 0;
603 break;
604 }
605 z += n;
606 while( isspace(*(u8*)z) ) z++;
607 n = strlen(z);
608 if( n>10 || n<3 ) break;
609 if( z[n-1]=='s' ){ z[n-1] = 0; n--; }
610 computeJD(p);
611 rc = 0;
612 if( n==3 && strcmp(z,"day")==0 ){
613 p->rJD += r;
614 }else if( n==4 && strcmp(z,"hour")==0 ){
615 p->rJD += r/24.0;
616 }else if( n==6 && strcmp(z,"minute")==0 ){
617 p->rJD += r/(24.0*60.0);
618 }else if( n==6 && strcmp(z,"second")==0 ){
619 p->rJD += r/(24.0*60.0*60.0);
620 }else if( n==5 && strcmp(z,"month")==0 ){
621 int x, y;
622 computeYMD_HMS(p);
623 p->M += r;
624 x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
625 p->Y += x;
626 p->M -= x*12;
627 p->validJD = 0;
628 computeJD(p);
629 y = r;
630 if( y!=r ){
631 p->rJD += (r - y)*30.0;
632 }
633 }else if( n==4 && strcmp(z,"year")==0 ){
634 computeYMD_HMS(p);
635 p->Y += r;
636 p->validJD = 0;
637 computeJD(p);
638 }else{
639 rc = 1;
640 }
641 clearYMD_HMS_TZ(p);
642 break;
643 }
644 default: {
645 break;
646 }
647 }
648 return rc;
649}
650
651/*
652** Process time function arguments. argv[0] is a date-time stamp.
653** argv[1] and following are modifiers. Parse them all and write
654** the resulting time into the DateTime structure p. Return 0
655** on success and 1 if there are any errors.
656*/
657static int isDate(
658 sqlite3_context *context,
659 int argc,
660 sqlite3_value **argv,
661 DateTime *p
662){
663 int i;
664 const unsigned char *z;
665 if( argc==0 ) return 1;
666 z = sqlite3_value_text(argv[0]);
667 if( !z || parseDateOrTime(context, (char*)z, p) ){
668 return 1;
669 }
670 for(i=1; i<argc; i++){
671 if( (z = sqlite3_value_text(argv[i]))==0 || parseModifier((char*)z, p) ){
672 return 1;
673 }
674 }
675 return 0;
676}
677
678
679/*
680** The following routines implement the various date and time functions
681** of SQLite.
682*/
683
684/*
685** julianday( TIMESTRING, MOD, MOD, ...)
686**
687** Return the julian day number of the date specified in the arguments
688*/
689static void juliandayFunc(
690 sqlite3_context *context,
691 int argc,
692 sqlite3_value **argv
693){
694 DateTime x;
695 if( isDate(context, argc, argv, &x)==0 ){
696 computeJD(&x);
697 sqlite3_result_double(context, x.rJD);
698 }
699}
700
701/*
702** datetime( TIMESTRING, MOD, MOD, ...)
703**
704** Return YYYY-MM-DD HH:MM:SS
705*/
706static void datetimeFunc(
707 sqlite3_context *context,
708 int argc,
709 sqlite3_value **argv
710){
711 DateTime x;
712 if( isDate(context, argc, argv, &x)==0 ){
713 char zBuf[100];
714 computeYMD_HMS(&x);
715 sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d %02d:%02d:%02d",
716 x.Y, x.M, x.D, x.h, x.m, (int)(x.s));
717 sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
718 }
719}
720
721/*
722** time( TIMESTRING, MOD, MOD, ...)
723**
724** Return HH:MM:SS
725*/
726static void timeFunc(
727 sqlite3_context *context,
728 int argc,
729 sqlite3_value **argv
730){
731 DateTime x;
732 if( isDate(context, argc, argv, &x)==0 ){
733 char zBuf[100];
734 computeHMS(&x);
735 sqlite3_snprintf(sizeof(zBuf), zBuf, "%02d:%02d:%02d", x.h, x.m, (int)x.s);
736 sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
737 }
738}
739
740/*
741** date( TIMESTRING, MOD, MOD, ...)
742**
743** Return YYYY-MM-DD
744*/
745static void dateFunc(
746 sqlite3_context *context,
747 int argc,
748 sqlite3_value **argv
749){
750 DateTime x;
751 if( isDate(context, argc, argv, &x)==0 ){
752 char zBuf[100];
753 computeYMD(&x);
754 sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d", x.Y, x.M, x.D);
755 sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
756 }
757}
758
759/*
760** strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
761**
762** Return a string described by FORMAT. Conversions as follows:
763**
764** %d day of month
765** %f ** fractional seconds SS.SSS
766** %H hour 00-24
767** %j day of year 000-366
768** %J ** Julian day number
769** %m month 01-12
770** %M minute 00-59
771** %s seconds since 1970-01-01
772** %S seconds 00-59
773** %w day of week 0-6 sunday==0
774** %W week of year 00-53
775** %Y year 0000-9999
776** %% %
777*/
778static void strftimeFunc(
779 sqlite3_context *context,
780 int argc,
781 sqlite3_value **argv
782){
783 DateTime x;
784 u64 n;
785 int i, j;
786 char *z;
787 const char *zFmt = (const char*)sqlite3_value_text(argv[0]);
788 char zBuf[100];
789 if( zFmt==0 || isDate(context, argc-1, argv+1, &x) ) return;
790 for(i=0, n=1; zFmt[i]; i++, n++){
791 if( zFmt[i]=='%' ){
792 switch( zFmt[i+1] ){
793 case 'd':
794 case 'H':
795 case 'm':
796 case 'M':
797 case 'S':
798 case 'W':
799 n++;
800 /* fall thru */
801 case 'w':
802 case '%':
803 break;
804 case 'f':
805 n += 8;
806 break;
807 case 'j':
808 n += 3;
809 break;
810 case 'Y':
811 n += 8;
812 break;
813 case 's':
814 case 'J':
815 n += 50;
816 break;
817 default:
818 return; /* ERROR. return a NULL */
819 }
820 i++;
821 }
822 }
823 if( n<sizeof(zBuf) ){
824 z = zBuf;
825 }else if( n>SQLITE_MAX_LENGTH ){
826 sqlite3_result_error_toobig(context);
827 return;
828 }else{
829 z = sqlite3_malloc( n );
830 if( z==0 ) return;
831 }
832 computeJD(&x);
833 computeYMD_HMS(&x);
834 for(i=j=0; zFmt[i]; i++){
835 if( zFmt[i]!='%' ){
836 z[j++] = zFmt[i];
837 }else{
838 i++;
839 switch( zFmt[i] ){
840 case 'd': sqlite3_snprintf(3, &z[j],"%02d",x.D); j+=2; break;
841 case 'f': {
842 double s = x.s;
843 if( s>59.999 ) s = 59.999;
844 sqlite3_snprintf(7, &z[j],"%06.3f", s);
845 j += strlen(&z[j]);
846 break;
847 }
848 case 'H': sqlite3_snprintf(3, &z[j],"%02d",x.h); j+=2; break;
849 case 'W': /* Fall thru */
850 case 'j': {
851 int nDay; /* Number of days since 1st day of year */
852 DateTime y = x;
853 y.validJD = 0;
854 y.M = 1;
855 y.D = 1;
856 computeJD(&y);
857 nDay = x.rJD - y.rJD + 0.5;
858 if( zFmt[i]=='W' ){
859 int wd; /* 0=Monday, 1=Tuesday, ... 6=Sunday */
860 wd = ((int)(x.rJD+0.5)) % 7;
861 sqlite3_snprintf(3, &z[j],"%02d",(nDay+7-wd)/7);
862 j += 2;
863 }else{
864 sqlite3_snprintf(4, &z[j],"%03d",nDay+1);
865 j += 3;
866 }
867 break;
868 }
869 case 'J': {
870 sqlite3_snprintf(20, &z[j],"%.16g",x.rJD);
871 j+=strlen(&z[j]);
872 break;
873 }
874 case 'm': sqlite3_snprintf(3, &z[j],"%02d",x.M); j+=2; break;
875 case 'M': sqlite3_snprintf(3, &z[j],"%02d",x.m); j+=2; break;
876 case 's': {
877 sqlite3_snprintf(30,&z[j],"%d",
878 (int)((x.rJD-2440587.5)*86400.0 + 0.5));
879 j += strlen(&z[j]);
880 break;
881 }
882 case 'S': sqlite3_snprintf(3,&z[j],"%02d",(int)x.s); j+=2; break;
883 case 'w': z[j++] = (((int)(x.rJD+1.5)) % 7) + '0'; break;
884 case 'Y': sqlite3_snprintf(5,&z[j],"%04d",x.Y); j+=strlen(&z[j]);break;
885 case '%': z[j++] = '%'; break;
886 }
887 }
888 }
889 z[j] = 0;
890 sqlite3_result_text(context, z, -1, SQLITE_TRANSIENT);
891 if( z!=zBuf ){
892 sqlite3_free(z);
893 }
894}
895
896/*
897** current_time()
898**
899** This function returns the same value as time('now').
900*/
901static void ctimeFunc(
902 sqlite3_context *context,
903 int argc,
904 sqlite3_value **argv
905){
906 sqlite3_value *pVal = sqlite3ValueNew(0);
907 if( pVal ){
908 sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
909 timeFunc(context, 1, &pVal);
910 sqlite3ValueFree(pVal);
911 }
912}
913
914/*
915** current_date()
916**
917** This function returns the same value as date('now').
918*/
919static void cdateFunc(
920 sqlite3_context *context,
921 int argc,
922 sqlite3_value **argv
923){
924 sqlite3_value *pVal = sqlite3ValueNew(0);
925 if( pVal ){
926 sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
927 dateFunc(context, 1, &pVal);
928 sqlite3ValueFree(pVal);
929 }
930}
931
932/*
933** current_timestamp()
934**
935** This function returns the same value as datetime('now').
936*/
937static void ctimestampFunc(
938 sqlite3_context *context,
939 int argc,
940 sqlite3_value **argv
941){
942 sqlite3_value *pVal = sqlite3ValueNew(0);
943 if( pVal ){
944 sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
945 datetimeFunc(context, 1, &pVal);
946 sqlite3ValueFree(pVal);
947 }
948}
949#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
950
951#ifdef SQLITE_OMIT_DATETIME_FUNCS
952/*
953** If the library is compiled to omit the full-scale date and time
954** handling (to get a smaller binary), the following minimal version
955** of the functions current_time(), current_date() and current_timestamp()
956** are included instead. This is to support column declarations that
957** include "DEFAULT CURRENT_TIME" etc.
958**
959** This function uses the C-library functions time(), gmtime()
960** and strftime(). The format string to pass to strftime() is supplied
961** as the user-data for the function.
962*/
963static void currentTimeFunc(
964 sqlite3_context *context,
965 int argc,
966 sqlite3_value **argv
967){
968 time_t t;
969 char *zFormat = (char *)sqlite3_user_data(context);
970 char zBuf[20];
971
972 time(&t);
973#ifdef SQLITE_TEST
974 {
975 extern int sqlite3_current_time; /* See os_XXX.c */
976 if( sqlite3_current_time ){
977 t = sqlite3_current_time;
978 }
979 }
980#endif
981
982#ifdef HAVE_GMTIME_R
983 {
984 struct tm sNow;
985 gmtime_r(&t, &sNow);
986 strftime(zBuf, 20, zFormat, &sNow);
987 }
988#else
989 {
990 struct tm *pTm;
991 sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
992 pTm = gmtime(&t);
993 strftime(zBuf, 20, zFormat, pTm);
994 sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
995 }
996#endif
997
998 sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
999}
1000#endif
1001
1002/*
1003** This function registered all of the above C functions as SQL
1004** functions. This should be the only routine in this file with
1005** external linkage.
1006*/
1007void sqlite3RegisterDateTimeFunctions(sqlite3 *db){
1008#ifndef SQLITE_OMIT_DATETIME_FUNCS
1009 static const struct {
1010 char *zName;
1011 int nArg;
1012 void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
1013 } aFuncs[] = {
1014 { "julianday", -1, juliandayFunc },
1015 { "date", -1, dateFunc },
1016 { "time", -1, timeFunc },
1017 { "datetime", -1, datetimeFunc },
1018 { "strftime", -1, strftimeFunc },
1019 { "current_time", 0, ctimeFunc },
1020 { "current_timestamp", 0, ctimestampFunc },
1021 { "current_date", 0, cdateFunc },
1022 };
1023 int i;
1024
1025 for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
1026 sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
1027 SQLITE_UTF8, (void *)(db->pVfs), aFuncs[i].xFunc, 0, 0);
1028 }
1029#else
1030 static const struct {
1031 char *zName;
1032 char *zFormat;
1033 } aFuncs[] = {
1034 { "current_time", "%H:%M:%S" },
1035 { "current_date", "%Y-%m-%d" },
1036 { "current_timestamp", "%Y-%m-%d %H:%M:%S" }
1037 };
1038 int i;
1039
1040 for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
1041 sqlite3CreateFunc(db, aFuncs[i].zName, 0, SQLITE_UTF8,
1042 aFuncs[i].zFormat, currentTimeFunc, 0, 0);
1043 }
1044#endif
1045}
generated by cgit v1.1 at 2024-12-24 07:00:41 +0000