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postgresql/src/timezone/strftime.c

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/* Convert a broken-down timestamp 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 "private.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 and later require this format. Using just numbers (as here) makes
* Quakers happier; it's also compatible with SVR4.
*/
"%m/%d/%y",
/*
* c_fmt
*
* C99 and later require 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"
};
enum warn
{
IN_NONE, IN_SOME, IN_THIS, IN_ALL
};
static char *_add(const char *str, char *pt, const char *ptlim);
static char *_conv(int n, const char *format, char *pt, const char *ptlim);
static char *_fmt(const char *format, const struct pg_tm *t, char *pt, const char *ptlim,
enum warn *warnp);
static char *_yconv(int a, int b, bool convert_top, bool convert_yy, char *pt, char const *ptlim);
/*
* Convert timestamp t to string s, a caller-allocated buffer of size maxsize,
* using the given format pattern.
*
* See also timestamptz_to_str.
*/
size_t
pg_strftime(char *s, size_t maxsize, const char *format, const struct pg_tm *t)
{
char *p;
int saved_errno = errno;
enum warn warn = IN_NONE;
p = _fmt(format, t, s, s + maxsize, &warn);
if (!p)
{
errno = EOVERFLOW;
return 0;
}
if (p == s + maxsize)
{
errno = ERANGE;
return 0;
}
*p = '\0';
errno = saved_errno;
return p - s;
}
static char *
_fmt(const char *format, const struct pg_tm *t, char *pt,
const char *ptlim, enum warn *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':
{
enum warn 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':
/*
* Locale modifiers of C99 and later. 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 alternative
* 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 <https://www.cl.cam.ac.uk/~mgk25/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':
{
enum warn 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 and later say that %Z must be replaced by the empty
* string if the time zone abbreviation is not
* determinable.
*/
continue;
case 'z':
{
long diff;
char const *sign;
bool negative;
if (t->tm_isdst < 0)
continue;
diff = t->tm_gmtoff;
negative = diff < 0;
if (diff == 0)
{
if (t->tm_zone != NULL)
negative = t->tm_zone[0] == '-';
}
if (negative)
{
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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