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postgres/src/timezone/strftime.c
Tom Lane 19d477aa68 Sync back-branch copies of the timezone code with IANA release tzcode2016c. 
Back-patch commit 1c1a7cbd6a, along with subsequent portability
fixes, into all active branches.  Also, back-patch commits 696027727 and
596857043 (addition of zic -P option) into 9.1 and 9.2, just to reduce
differences between the branches.  src/timezone/ is now largely identical
in all active branches, except that in 9.1, pgtz.c retains the
initial-timezone-selection code that was moved over to initdb in 9.2.

Ordinarily we wouldn't risk this much code churn in back branches, but it
seems necessary in this case, because among the changes are two feature
additions in the "zic" zone data file compiler (a larger limit on the
number of allowed DST transitions, and addition of a "%z" escape in zone
abbreviations).  IANA have not yet started to use those features in their
tzdata files, but presumably they will before too long.  If we don't update
then we'll be unable to adopt new timezone data.  Also, installations built
with --with-system-tzdata (which includes most distro-supplied builds, I
believe) might fail even if we don't update our copies of the data files.
There are assorted bug fixes too, mostly affecting obscure timezones or
post-2037 dates.

Discussion: <13601.1468868947@sss.pgh.pa.us>
2016-07-19 15:59:36 -04:00

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/* Convert a broken-down time stamp to a string. */
/*
* Copyright 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Based on the UCB version with the copyright notice appearing above.
*
* This is ANSIish only when "multibyte character == plain character".
*
* IDENTIFICATION
* src/timezone/strftime.c
*/
#include "postgres.h"
#include <fcntl.h>
#include <locale.h>
#include "private.h"
#include "tzfile.h"
struct lc_time_T
{
const char *mon[MONSPERYEAR];
const char *month[MONSPERYEAR];
const char *wday[DAYSPERWEEK];
const char *weekday[DAYSPERWEEK];
const char *X_fmt;
const char *x_fmt;
const char *c_fmt;
const char *am;
const char *pm;
const char *date_fmt;
};
#define Locale (&C_time_locale)
static const struct lc_time_T C_time_locale = {
{
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
}, {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
}, {
"Sun", "Mon", "Tue", "Wed",
"Thu", "Fri", "Sat"
}, {
"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday"
},
/* X_fmt */
"%H:%M:%S",
/*
* x_fmt
*
* C99 requires this format. Using just numbers (as here) makes Quakers
* happier; it's also compatible with SVR4.
*/
"%m/%d/%y",
/*
* c_fmt
*
* C99 requires this format. Previously this code used "%D %X", but we now
* conform to C99. Note that "%a %b %d %H:%M:%S %Y" is used by Solaris
* 2.3.
*/
"%a %b %e %T %Y",
/* am */
"AM",
/* pm */
"PM",
/* date_fmt */
"%a %b %e %H:%M:%S %Z %Y"
};
static char *_add(const char *, char *, const char *);
static char *_conv(int, const char *, char *, const char *);
static char *_fmt(const char *, const struct pg_tm *, char *,
const char *, int *);
static char *_yconv(int, int, bool, bool, char *, const char *);
#define IN_NONE 0
#define IN_SOME 1
#define IN_THIS 2
#define IN_ALL 3
size_t
pg_strftime(char *s, size_t maxsize, const char *format,
const struct pg_tm * t)
{
char *p;
int warn;
warn = IN_NONE;
p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
if (p == s + maxsize)
return 0;
*p = '\0';
return p - s;
}
static char *
_fmt(const char *format, const struct pg_tm * t, char *pt, const char *ptlim,
int *warnp)
{
for (; *format; ++format)
{
if (*format == '%')
{
label:
switch (*++format)
{
case '\0':
--format;
break;
case 'A':
pt = _add((t->tm_wday < 0 ||
t->tm_wday >= DAYSPERWEEK) ?
"?" : Locale->weekday[t->tm_wday],
pt, ptlim);
continue;
case 'a':
pt = _add((t->tm_wday < 0 ||
t->tm_wday >= DAYSPERWEEK) ?
"?" : Locale->wday[t->tm_wday],
pt, ptlim);
continue;
case 'B':
pt = _add((t->tm_mon < 0 ||
t->tm_mon >= MONSPERYEAR) ?
"?" : Locale->month[t->tm_mon],
pt, ptlim);
continue;
case 'b':
case 'h':
pt = _add((t->tm_mon < 0 ||
t->tm_mon >= MONSPERYEAR) ?
"?" : Locale->mon[t->tm_mon],
pt, ptlim);
continue;
case 'C':
/*
* %C used to do a... _fmt("%a %b %e %X %Y", t);
* ...whereas now POSIX 1003.2 calls for something
* completely different. (ado, 1993-05-24)
*/
pt = _yconv(t->tm_year, TM_YEAR_BASE,
true, false, pt, ptlim);
continue;
case 'c':
{
int warn2 = IN_SOME;
pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
if (warn2 == IN_ALL)
warn2 = IN_THIS;
if (warn2 > *warnp)
*warnp = warn2;
}
continue;
case 'D':
pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
continue;
case 'd':
pt = _conv(t->tm_mday, "%02d", pt, ptlim);
continue;
case 'E':
case 'O':
/*
* C99 locale modifiers. The sequences %Ec %EC %Ex %EX
* %Ey %EY %Od %oe %OH %OI %Om %OM %OS %Ou %OU %OV %Ow
* %OW %Oy are supposed to provide alternate
* representations.
*/
goto label;
case 'e':
pt = _conv(t->tm_mday, "%2d", pt, ptlim);
continue;
case 'F':
pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
continue;
case 'H':
pt = _conv(t->tm_hour, "%02d", pt, ptlim);
continue;
case 'I':
pt = _conv((t->tm_hour % 12) ?
(t->tm_hour % 12) : 12,
"%02d", pt, ptlim);
continue;
case 'j':
pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
continue;
case 'k':
/*
* This used to be... _conv(t->tm_hour % 12 ? t->tm_hour
* % 12 : 12, 2, ' '); ...and has been changed to the
* below to match SunOS 4.1.1 and Arnold Robbins' strftime
* version 3.0. That is, "%k" and "%l" have been swapped.
* (ado, 1993-05-24)
*/
pt = _conv(t->tm_hour, "%2d", pt, ptlim);
continue;
#ifdef KITCHEN_SINK
case 'K':
/*
* After all this time, still unclaimed!
*/
pt = _add("kitchen sink", pt, ptlim);
continue;
#endif /* defined KITCHEN_SINK */
case 'l':
/*
* This used to be... _conv(t->tm_hour, 2, ' '); ...and
* has been changed to the below to match SunOS 4.1.1 and
* Arnold Robbin's strftime version 3.0. That is, "%k" and
* "%l" have been swapped. (ado, 1993-05-24)
*/
pt = _conv((t->tm_hour % 12) ?
(t->tm_hour % 12) : 12,
"%2d", pt, ptlim);
continue;
case 'M':
pt = _conv(t->tm_min, "%02d", pt, ptlim);
continue;
case 'm':
pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
continue;
case 'n':
pt = _add("\n", pt, ptlim);
continue;
case 'p':
pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
Locale->pm :
Locale->am,
pt, ptlim);
continue;
case 'R':
pt = _fmt("%H:%M", t, pt, ptlim, warnp);
continue;
case 'r':
pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
continue;
case 'S':
pt = _conv(t->tm_sec, "%02d", pt, ptlim);
continue;
case 'T':
pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
continue;
case 't':
pt = _add("\t", pt, ptlim);
continue;
case 'U':
pt = _conv((t->tm_yday + DAYSPERWEEK -
t->tm_wday) / DAYSPERWEEK,
"%02d", pt, ptlim);
continue;
case 'u':
/*
* From Arnold Robbins' strftime version 3.0: "ISO 8601:
* Weekday as a decimal number [1 (Monday) - 7]" (ado,
* 1993-05-24)
*/
pt = _conv((t->tm_wday == 0) ?
DAYSPERWEEK : t->tm_wday,
"%d", pt, ptlim);
continue;
case 'V': /* ISO 8601 week number */
case 'G': /* ISO 8601 year (four digits) */
case 'g': /* ISO 8601 year (two digits) */
/*
* From Arnold Robbins' strftime version 3.0: "the week number of the
* year (the first Monday as the first day of week 1) as a decimal number
* (01-53)."
* (ado, 1993-05-24)
*
* From <http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html> by Markus Kuhn:
* "Week 01 of a year is per definition the first week which has the
* Thursday in this year, which is equivalent to the week which contains
* the fourth day of January. In other words, the first week of a new year
* is the week which has the majority of its days in the new year. Week 01
* might also contain days from the previous year and the week before week
* 01 of a year is the last week (52 or 53) of the previous year even if
* it contains days from the new year. A week starts with Monday (day 1)
* and ends with Sunday (day 7). For example, the first week of the year
* 1997 lasts from 1996-12-30 to 1997-01-05..."
* (ado, 1996-01-02)
*/
{
int year;
int base;
int yday;
int wday;
int w;
year = t->tm_year;
base = TM_YEAR_BASE;
yday = t->tm_yday;
wday = t->tm_wday;
for (;;)
{
int len;
int bot;
int top;
len = isleap_sum(year, base) ?
DAYSPERLYEAR :
DAYSPERNYEAR;
/*
* What yday (-3 ... 3) does the ISO year begin
* on?
*/
bot = ((yday + 11 - wday) %
DAYSPERWEEK) - 3;
/*
* What yday does the NEXT ISO year begin on?
*/
top = bot -
(len % DAYSPERWEEK);
if (top < -3)
top += DAYSPERWEEK;
top += len;
if (yday >= top)
{
++base;
w = 1;
break;
}
if (yday >= bot)
{
w = 1 + ((yday - bot) /
DAYSPERWEEK);
break;
}
--base;
yday += isleap_sum(year, base) ?
DAYSPERLYEAR :
DAYSPERNYEAR;
}
if (*format == 'V')
pt = _conv(w, "%02d",
pt, ptlim);
else if (*format == 'g')
{
*warnp = IN_ALL;
pt = _yconv(year, base,
false, true,
pt, ptlim);
}
else
pt = _yconv(year, base,
true, true,
pt, ptlim);
}
continue;
case 'v':
/*
* From Arnold Robbins' strftime version 3.0: "date as
* dd-bbb-YYYY" (ado, 1993-05-24)
*/
pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
continue;
case 'W':
pt = _conv((t->tm_yday + DAYSPERWEEK -
(t->tm_wday ?
(t->tm_wday - 1) :
(DAYSPERWEEK - 1))) / DAYSPERWEEK,
"%02d", pt, ptlim);
continue;
case 'w':
pt = _conv(t->tm_wday, "%d", pt, ptlim);
continue;
case 'X':
pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
continue;
case 'x':
{
int warn2 = IN_SOME;
pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
if (warn2 == IN_ALL)
warn2 = IN_THIS;
if (warn2 > *warnp)
*warnp = warn2;
}
continue;
case 'y':
*warnp = IN_ALL;
pt = _yconv(t->tm_year, TM_YEAR_BASE,
false, true,
pt, ptlim);
continue;
case 'Y':
pt = _yconv(t->tm_year, TM_YEAR_BASE,
true, true,
pt, ptlim);
continue;
case 'Z':
if (t->tm_zone != NULL)
pt = _add(t->tm_zone, pt, ptlim);
/*
* C99 says that %Z must be replaced by the empty string
* if the time zone is not determinable.
*/
continue;
case 'z':
{
long diff;
char const *sign;
if (t->tm_isdst < 0)
continue;
diff = t->tm_gmtoff;
if (diff < 0)
{
sign = "-";
diff = -diff;
}
else
sign = "+";
pt = _add(sign, pt, ptlim);
diff /= SECSPERMIN;
diff = (diff / MINSPERHOUR) * 100 +
(diff % MINSPERHOUR);
pt = _conv(diff, "%04d", pt, ptlim);
}
continue;
case '+':
pt = _fmt(Locale->date_fmt, t, pt, ptlim,
warnp);
continue;
case '%':
/*
* X311J/88-090 (4.12.3.5): if conversion char is
* undefined, behavior is undefined. Print out the
* character itself as printf(3) also does.
*/
default:
break;
}
}
if (pt == ptlim)
break;
*pt++ = *format;
}
return pt;
}
static char *
_conv(int n, const char *format, char *pt, const char *ptlim)
{
char buf[INT_STRLEN_MAXIMUM(int) +1];
sprintf(buf, format, n);
return _add(buf, pt, ptlim);
}
static char *
_add(const char *str, char *pt, const char *ptlim)
{
while (pt < ptlim && (*pt = *str++) != '\0')
++pt;
return pt;
}
/*
* POSIX and the C Standard are unclear or inconsistent about
* what %C and %y do if the year is negative or exceeds 9999.
* Use the convention that %C concatenated with %y yields the
* same output as %Y, and that %Y contains at least 4 bytes,
* with more only if necessary.
*/
static char *
_yconv(int a, int b, bool convert_top, bool convert_yy,
char *pt, const char *ptlim)
{
int lead;
int trail;
#define DIVISOR 100
trail = a % DIVISOR + b % DIVISOR;
lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
trail %= DIVISOR;
if (trail < 0 && lead > 0)
{
trail += DIVISOR;
--lead;
}
else if (lead < 0 && trail > 0)
{
trail -= DIVISOR;
++lead;
}
if (convert_top)
{
if (lead == 0 && trail < 0)
pt = _add("-0", pt, ptlim);
else
pt = _conv(lead, "%02d", pt, ptlim);
}
if (convert_yy)
pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
return pt;
}
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