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strftime.c
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1/* Convert a broken-down timestamp to a string. */
2
3/*
4 * Copyright 1989 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32/*
33 * Based on the UCB version with the copyright notice appearing above.
34 *
35 * This is ANSIish only when "multibyte character == plain character".
36 *
37 * IDENTIFICATION
38 * src/timezone/strftime.c
39 */
40
41#include "postgres.h"
42
43#include <fcntl.h>
44
45#include "private.h"
46
47
49{
50 const char *mon[MONSPERYEAR];
51 const char *month[MONSPERYEAR];
52 const char *wday[DAYSPERWEEK];
53 const char *weekday[DAYSPERWEEK];
54 const char *X_fmt;
55 const char *x_fmt;
56 const char *c_fmt;
57 const char *am;
58 const char *pm;
59 const char *date_fmt;
60};
61
62#define Locale (&C_time_locale)
63
64static const struct lc_time_T C_time_locale = {
65 {
66 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
67 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
68 }, {
69 "January", "February", "March", "April", "May", "June",
70 "July", "August", "September", "October", "November", "December"
71 }, {
72 "Sun", "Mon", "Tue", "Wed",
73 "Thu", "Fri", "Sat"
74 }, {
75 "Sunday", "Monday", "Tuesday", "Wednesday",
76 "Thursday", "Friday", "Saturday"
77 },
78
79 /* X_fmt */
80 "%H:%M:%S",
81
82 /*
83 * x_fmt
84 *
85 * C99 and later require this format. Using just numbers (as here) makes
86 * Quakers happier; it's also compatible with SVR4.
87 */
88 "%m/%d/%y",
89
90 /*
91 * c_fmt
92 *
93 * C99 and later require this format. Previously this code used "%D %X",
94 * but we now conform to C99. Note that "%a %b %d %H:%M:%S %Y" is used by
95 * Solaris 2.3.
96 */
97 "%a %b %e %T %Y",
98
99 /* am */
100 "AM",
101
102 /* pm */
103 "PM",
104
105 /* date_fmt */
106 "%a %b %e %H:%M:%S %Z %Y"
107};
108
110{
113
114static char *_add(const char *str, char *pt, const char *ptlim);
115static char *_conv(int n, const char *format, char *pt, const char *ptlim);
116static char *_fmt(const char *format, const struct pg_tm *t, char *pt, const char *ptlim,
117 enum warn *warnp);
118static char *_yconv(int a, int b, bool convert_top, bool convert_yy, char *pt, char const *ptlim);
119
120
121/*
122 * Convert timestamp t to string s, a caller-allocated buffer of size maxsize,
123 * using the given format pattern.
124 *
125 * See also timestamptz_to_str.
126 */
127size_t
128pg_strftime(char *s, size_t maxsize, const char *format, const struct pg_tm *t)
129{
130 char *p;
131 int saved_errno = errno;
132 enum warn warn = IN_NONE;
133
134 p = _fmt(format, t, s, s + maxsize, &warn);
135 if (!p)
136 {
137 errno = EOVERFLOW;
138 return 0;
139 }
140 if (p == s + maxsize)
141 {
142 errno = ERANGE;
143 return 0;
144 }
145 *p = '\0';
146 errno = saved_errno;
147 return p - s;
148}
149
150static char *
151_fmt(const char *format, const struct pg_tm *t, char *pt,
152 const char *ptlim, enum warn *warnp)
153{
154 for (; *format; ++format)
155 {
156 if (*format == '%')
157 {
158 label:
159 switch (*++format)
160 {
161 case '\0':
162 --format;
163 break;
164 case 'A':
165 pt = _add((t->tm_wday < 0 ||
166 t->tm_wday >= DAYSPERWEEK) ?
167 "?" : Locale->weekday[t->tm_wday],
168 pt, ptlim);
169 continue;
170 case 'a':
171 pt = _add((t->tm_wday < 0 ||
172 t->tm_wday >= DAYSPERWEEK) ?
173 "?" : Locale->wday[t->tm_wday],
174 pt, ptlim);
175 continue;
176 case 'B':
177 pt = _add((t->tm_mon < 0 ||
178 t->tm_mon >= MONSPERYEAR) ?
179 "?" : Locale->month[t->tm_mon],
180 pt, ptlim);
181 continue;
182 case 'b':
183 case 'h':
184 pt = _add((t->tm_mon < 0 ||
185 t->tm_mon >= MONSPERYEAR) ?
186 "?" : Locale->mon[t->tm_mon],
187 pt, ptlim);
188 continue;
189 case 'C':
190
191 /*
192 * %C used to do a... _fmt("%a %b %e %X %Y", t);
193 * ...whereas now POSIX 1003.2 calls for something
194 * completely different. (ado, 1993-05-24)
195 */
196 pt = _yconv(t->tm_year, TM_YEAR_BASE,
197 true, false, pt, ptlim);
198 continue;
199 case 'c':
200 {
201 enum warn warn2 = IN_SOME;
202
203 pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
204 if (warn2 == IN_ALL)
205 warn2 = IN_THIS;
206 if (warn2 > *warnp)
207 *warnp = warn2;
208 }
209 continue;
210 case 'D':
211 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
212 continue;
213 case 'd':
214 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
215 continue;
216 case 'E':
217 case 'O':
218
219 /*
220 * Locale modifiers of C99 and later. The sequences %Ec
221 * %EC %Ex %EX %Ey %EY %Od %oe %OH %OI %Om %OM %OS %Ou %OU
222 * %OV %Ow %OW %Oy are supposed to provide alternative
223 * representations.
224 */
225 goto label;
226 case 'e':
227 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
228 continue;
229 case 'F':
230 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
231 continue;
232 case 'H':
233 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
234 continue;
235 case 'I':
236 pt = _conv((t->tm_hour % 12) ?
237 (t->tm_hour % 12) : 12,
238 "%02d", pt, ptlim);
239 continue;
240 case 'j':
241 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
242 continue;
243 case 'k':
244
245 /*
246 * This used to be... _conv(t->tm_hour % 12 ? t->tm_hour %
247 * 12 : 12, 2, ' '); ...and has been changed to the below
248 * to match SunOS 4.1.1 and Arnold Robbins' strftime
249 * version 3.0. That is, "%k" and "%l" have been swapped.
250 * (ado, 1993-05-24)
251 */
252 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
253 continue;
254#ifdef KITCHEN_SINK
255 case 'K':
256
257 /*
258 * After all this time, still unclaimed!
259 */
260 pt = _add("kitchen sink", pt, ptlim);
261 continue;
262#endif /* defined KITCHEN_SINK */
263 case 'l':
264
265 /*
266 * This used to be... _conv(t->tm_hour, 2, ' '); ...and
267 * has been changed to the below to match SunOS 4.1.1 and
268 * Arnold Robbin's strftime version 3.0. That is, "%k" and
269 * "%l" have been swapped. (ado, 1993-05-24)
270 */
271 pt = _conv((t->tm_hour % 12) ?
272 (t->tm_hour % 12) : 12,
273 "%2d", pt, ptlim);
274 continue;
275 case 'M':
276 pt = _conv(t->tm_min, "%02d", pt, ptlim);
277 continue;
278 case 'm':
279 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
280 continue;
281 case 'n':
282 pt = _add("\n", pt, ptlim);
283 continue;
284 case 'p':
285 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
286 Locale->pm :
287 Locale->am,
288 pt, ptlim);
289 continue;
290 case 'R':
291 pt = _fmt("%H:%M", t, pt, ptlim, warnp);
292 continue;
293 case 'r':
294 pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
295 continue;
296 case 'S':
297 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
298 continue;
299 case 'T':
300 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
301 continue;
302 case 't':
303 pt = _add("\t", pt, ptlim);
304 continue;
305 case 'U':
306 pt = _conv((t->tm_yday + DAYSPERWEEK -
307 t->tm_wday) / DAYSPERWEEK,
308 "%02d", pt, ptlim);
309 continue;
310 case 'u':
311
312 /*
313 * From Arnold Robbins' strftime version 3.0: "ISO 8601:
314 * Weekday as a decimal number [1 (Monday) - 7]" (ado,
315 * 1993-05-24)
316 */
317 pt = _conv((t->tm_wday == 0) ?
318 DAYSPERWEEK : t->tm_wday,
319 "%d", pt, ptlim);
320 continue;
321 case 'V': /* ISO 8601 week number */
322 case 'G': /* ISO 8601 year (four digits) */
323 case 'g': /* ISO 8601 year (two digits) */
324/*
325 * From Arnold Robbins' strftime version 3.0: "the week number of the
326 * year (the first Monday as the first day of week 1) as a decimal number
327 * (01-53)."
328 * (ado, 1993-05-24)
329 *
330 * From <https://www.cl.cam.ac.uk/~mgk25/iso-time.html> by Markus Kuhn:
331 * "Week 01 of a year is per definition the first week which has the
332 * Thursday in this year, which is equivalent to the week which contains
333 * the fourth day of January. In other words, the first week of a new year
334 * is the week which has the majority of its days in the new year. Week 01
335 * might also contain days from the previous year and the week before week
336 * 01 of a year is the last week (52 or 53) of the previous year even if
337 * it contains days from the new year. A week starts with Monday (day 1)
338 * and ends with Sunday (day 7). For example, the first week of the year
339 * 1997 lasts from 1996-12-30 to 1997-01-05..."
340 * (ado, 1996-01-02)
341 */
342 {
343 int year;
344 int base;
345 int yday;
346 int wday;
347 int w;
348
349 year = t->tm_year;
350 base = TM_YEAR_BASE;
351 yday = t->tm_yday;
352 wday = t->tm_wday;
353 for (;;)
354 {
355 int len;
356 int bot;
357 int top;
358
359 len = isleap_sum(year, base) ?
362
363 /*
364 * What yday (-3 ... 3) does the ISO year begin
365 * on?
366 */
367 bot = ((yday + 11 - wday) %
368 DAYSPERWEEK) - 3;
369
370 /*
371 * What yday does the NEXT ISO year begin on?
372 */
373 top = bot -
374 (len % DAYSPERWEEK);
375 if (top < -3)
376 top += DAYSPERWEEK;
377 top += len;
378 if (yday >= top)
379 {
380 ++base;
381 w = 1;
382 break;
383 }
384 if (yday >= bot)
385 {
386 w = 1 + ((yday - bot) /
388 break;
389 }
390 --base;
391 yday += isleap_sum(year, base) ?
394 }
395 if (*format == 'V')
396 pt = _conv(w, "%02d",
397 pt, ptlim);
398 else if (*format == 'g')
399 {
400 *warnp = IN_ALL;
401 pt = _yconv(year, base,
402 false, true,
403 pt, ptlim);
404 }
405 else
406 pt = _yconv(year, base,
407 true, true,
408 pt, ptlim);
409 }
410 continue;
411 case 'v':
412
413 /*
414 * From Arnold Robbins' strftime version 3.0: "date as
415 * dd-bbb-YYYY" (ado, 1993-05-24)
416 */
417 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
418 continue;
419 case 'W':
420 pt = _conv((t->tm_yday + DAYSPERWEEK -
421 (t->tm_wday ?
422 (t->tm_wday - 1) :
423 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
424 "%02d", pt, ptlim);
425 continue;
426 case 'w':
427 pt = _conv(t->tm_wday, "%d", pt, ptlim);
428 continue;
429 case 'X':
430 pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
431 continue;
432 case 'x':
433 {
434 enum warn warn2 = IN_SOME;
435
436 pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
437 if (warn2 == IN_ALL)
438 warn2 = IN_THIS;
439 if (warn2 > *warnp)
440 *warnp = warn2;
441 }
442 continue;
443 case 'y':
444 *warnp = IN_ALL;
445 pt = _yconv(t->tm_year, TM_YEAR_BASE,
446 false, true,
447 pt, ptlim);
448 continue;
449 case 'Y':
450 pt = _yconv(t->tm_year, TM_YEAR_BASE,
451 true, true,
452 pt, ptlim);
453 continue;
454 case 'Z':
455 if (t->tm_zone != NULL)
456 pt = _add(t->tm_zone, pt, ptlim);
457
458 /*
459 * C99 and later say that %Z must be replaced by the empty
460 * string if the time zone abbreviation is not
461 * determinable.
462 */
463 continue;
464 case 'z':
465 {
466 long diff;
467 char const *sign;
468 bool negative;
469
470 if (t->tm_isdst < 0)
471 continue;
472 diff = t->tm_gmtoff;
473 negative = diff < 0;
474 if (diff == 0)
475 {
476 if (t->tm_zone != NULL)
477 negative = t->tm_zone[0] == '-';
478 }
479 if (negative)
480 {
481 sign = "-";
482 diff = -diff;
483 }
484 else
485 sign = "+";
486 pt = _add(sign, pt, ptlim);
487 diff /= SECSPERMIN;
488 diff = (diff / MINSPERHOUR) * 100 +
489 (diff % MINSPERHOUR);
490 pt = _conv(diff, "%04d", pt, ptlim);
491 }
492 continue;
493 case '+':
494 pt = _fmt(Locale->date_fmt, t, pt, ptlim,
495 warnp);
496 continue;
497 case '%':
498
499 /*
500 * X311J/88-090 (4.12.3.5): if conversion char is
501 * undefined, behavior is undefined. Print out the
502 * character itself as printf(3) also does.
503 */
504 default:
505 break;
506 }
507 }
508 if (pt == ptlim)
509 break;
510 *pt++ = *format;
511 }
512 return pt;
513}
514
515static char *
516_conv(int n, const char *format, char *pt, const char *ptlim)
517{
518 char buf[INT_STRLEN_MAXIMUM(int) + 1];
519
520 sprintf(buf, format, n);
521 return _add(buf, pt, ptlim);
522}
523
524static char *
525_add(const char *str, char *pt, const char *ptlim)
526{
527 while (pt < ptlim && (*pt = *str++) != '\0')
528 ++pt;
529 return pt;
530}
531
532/*
533 * POSIX and the C Standard are unclear or inconsistent about
534 * what %C and %y do if the year is negative or exceeds 9999.
535 * Use the convention that %C concatenated with %y yields the
536 * same output as %Y, and that %Y contains at least 4 bytes,
537 * with more only if necessary.
538 */
539
540static char *
541_yconv(int a, int b, bool convert_top, bool convert_yy,
542 char *pt, const char *ptlim)
543{
544 int lead;
545 int trail;
546
547#define DIVISOR 100
548 trail = a % DIVISOR + b % DIVISOR;
549 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
550 trail %= DIVISOR;
551 if (trail < 0 && lead > 0)
552 {
553 trail += DIVISOR;
554 --lead;
555 }
556 else if (lead < 0 && trail > 0)
557 {
558 trail -= DIVISOR;
559 ++lead;
560 }
561 if (convert_top)
562 {
563 if (lead == 0 && trail < 0)
564 pt = _add("-0", pt, ptlim);
565 else
566 pt = _conv(lead, "%02d", pt, ptlim);
567 }
568 if (convert_yy)
569 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
570 return pt;
571}
const char * str
char sign
Definition: informix.c:693
int b
Definition: isn.c:69
int a
Definition: isn.c:68
static char format
static char * label
const void size_t len
static char * buf
Definition: pg_test_fsync.c:72
#define sprintf
Definition: port.h:240
#define TM_YEAR_BASE
Definition: private.h:128
#define INT_STRLEN_MAXIMUM(type)
Definition: private.h:81
#define DAYSPERNYEAR
Definition: private.h:101
#define SECSPERMIN
Definition: private.h:97
#define MONSPERYEAR
Definition: private.h:105
#define HOURSPERDAY
Definition: private.h:99
#define EOVERFLOW
Definition: private.h:41
#define DAYSPERWEEK
Definition: private.h:100
#define isleap_sum(a, b)
Definition: private.h:147
#define MINSPERHOUR
Definition: private.h:98
#define DAYSPERLYEAR
Definition: private.h:102
warn
Definition: strftime.c:110
@ IN_ALL
Definition: strftime.c:111
@ IN_NONE
Definition: strftime.c:111
@ IN_SOME
Definition: strftime.c:111
@ IN_THIS
Definition: strftime.c:111
static char * _add(const char *str, char *pt, const char *ptlim)
Definition: strftime.c:525
#define DIVISOR
static char * _fmt(const char *format, const struct pg_tm *t, char *pt, const char *ptlim, enum warn *warnp)
Definition: strftime.c:151
static char * _yconv(int a, int b, bool convert_top, bool convert_yy, char *pt, char const *ptlim)
Definition: strftime.c:541
static char * _conv(int n, const char *format, char *pt, const char *ptlim)
Definition: strftime.c:516
size_t pg_strftime(char *s, size_t maxsize, const char *format, const struct pg_tm *t)
Definition: strftime.c:128
#define Locale
Definition: strftime.c:62
static const struct lc_time_T C_time_locale
Definition: strftime.c:64
const char * am
Definition: strftime.c:57
const char * X_fmt
Definition: strftime.c:54
const char * mon[MONSPERYEAR]
Definition: strftime.c:50
const char * weekday[DAYSPERWEEK]
Definition: strftime.c:53
const char * wday[DAYSPERWEEK]
Definition: strftime.c:52
const char * month[MONSPERYEAR]
Definition: strftime.c:51
const char * x_fmt
Definition: strftime.c:55
const char * pm
Definition: strftime.c:58
const char * date_fmt
Definition: strftime.c:59
const char * c_fmt
Definition: strftime.c:56
Definition: pgtime.h:35
int tm_hour
Definition: pgtime.h:38
int tm_mday
Definition: pgtime.h:39
int tm_mon
Definition: pgtime.h:40
int tm_min
Definition: pgtime.h:37
const char * tm_zone
Definition: pgtime.h:46
int tm_yday
Definition: pgtime.h:43
int tm_wday
Definition: pgtime.h:42
int tm_sec
Definition: pgtime.h:36
int tm_isdst
Definition: pgtime.h:44
long int tm_gmtoff
Definition: pgtime.h:45
int tm_year
Definition: pgtime.h:41