/*-*- mode:c; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright (c) 1989 The Regents of the University of California. │
│ All rights reserved. │
│ │
│ Redistribution and use in source and binary forms are permitted │
│ provided that the above copyright notice and this paragraph are │
│ duplicated in all such forms and that any documentation, │
│ advertising materials, and other materials related to such │
│ distribution and use acknowledge that the software was developed │
│ by the University of California, Berkeley. The name of the │
│ University may not be used to endorse or promote products derived │
│ from this software without specific prior written permission. │
│ THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR │
│ IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/fmt/fmt.h"
#include "libc/inttypes.h"
#include "libc/stdio/stdio.h"
#include "libc/time/time.h"
#include "libc/time/tz.internal.h"
#include "libc/unicode/locale.h"
// clang-format off
// converts broken-down timestamp to string
#define DIVISOR 100
asm(".ident\t\"\\n\\n\
strftime (BSD-3)\\n\
Copyright 1989 The Regents of the University of California\"");
asm(".include \"libc/disclaimer.inc\"");
/*
** Based on the UCB version with the copyright notice appearing above.
**
** This is ANSIish only when "multibyte character == plain character".
*/
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 };
#ifndef YEAR_2000_NAME
#define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
#endif /* !defined YEAR_2000_NAME */
static char *
strftime_add(const char *str, char *pt, const char *ptlim)
{
while (pt < ptlim && (*pt = *str++) != '\0')
++pt;
return pt;
}
static char *
strftime_conv(int n, const char *format, char *pt, const char *ptlim)
{
char buf[INT_STRLEN_MAXIMUM(int) + 1];
(sprintf)(buf, format, n);
return strftime_add(buf, pt, ptlim);
}
/*
** 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 *
strftime_yconv(
int a,
int b,
bool convert_top,
bool convert_yy,
char *pt,
const char *ptlim)
{
register int lead;
register int trail;
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 = strftime_add("-0", pt, ptlim);
else pt = strftime_conv(lead, "%02d", pt, ptlim);
}
if (convert_yy)
pt = strftime_conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
return pt;
}
static char *
strftime_fmt(const char *format, const struct 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 = strftime_add(
(t->tm_wday < 0 ||
t->tm_wday >= DAYSPERWEEK) ?
"?" : Locale->weekday[t->tm_wday],
pt, ptlim);
continue;
case 'a':
pt = strftime_add(
(t->tm_wday < 0 ||
t->tm_wday >= DAYSPERWEEK) ?
"?" : Locale->wday[t->tm_wday],
pt, ptlim);
continue;
case 'B':
pt = strftime_add(
(t->tm_mon < 0 ||
t->tm_mon >= MONSPERYEAR) ?
"?" : Locale->month[t->tm_mon],
pt, ptlim);
continue;
case 'b':
case 'h':
pt = strftime_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 = strftime_yconv(t->tm_year, TM_YEAR_BASE,
true, false, pt, ptlim);
continue;
case 'c':
{
enum warn warn2 = IN_SOME;
pt = strftime_fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
if (warn2 == IN_ALL)
warn2 = IN_THIS;
if (warn2 > *warnp)
*warnp = warn2;
}
continue;
case 'D':
pt = strftime_fmt("%m/%d/%y", t, pt, ptlim, warnp);
continue;
case 'd':
pt = strftime_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 = strftime_conv(t->tm_mday, "%2d", pt, ptlim);
continue;
case 'F':
pt = strftime_fmt("%Y-%m-%d", t, pt, ptlim, warnp);
continue;
case 'H':
pt = strftime_conv(t->tm_hour, "%02d", pt, ptlim);
continue;
case 'I':
pt = strftime_conv((t->tm_hour % 12) ?
(t->tm_hour % 12) : 12,
"%02d", pt, ptlim);
continue;
case 'j':
pt = strftime_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 = strftime_conv(t->tm_hour, "%2d",
pt, ptlim);
continue;
#ifdef KITCHEN_SINK
case 'K':
/*
** After all this time, still unclaimed!
*/
pt = strftime_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 = strftime_conv((t->tm_hour % 12) ?
(t->tm_hour % 12) : 12,
"%2d", pt, ptlim);
continue;
case 'M':
pt = strftime_conv(t->tm_min, "%02d",
pt, ptlim);
continue;
case 'm':
pt = strftime_conv(t->tm_mon + 1, "%02d",
pt, ptlim);
continue;
case 'n':
pt = strftime_add("\n", pt, ptlim);
continue;
case 'p':
pt = strftime_add(
(t->tm_hour >= (HOURSPERDAY / 2)) ?
Locale->pm :
Locale->am,
pt, ptlim);
continue;
case 'R':
pt = strftime_fmt("%H:%M", t, pt, ptlim, warnp);
continue;
case 'r':
pt = strftime_fmt("%I:%M:%S %p", t, pt,
ptlim, warnp);
continue;
case 'S':
pt = strftime_conv(t->tm_sec, "%02d", pt,
ptlim);
continue;
case 's':
{
struct tm tm;
char buf[INT_STRLEN_MAXIMUM(
time_t) + 1];
time_t mkt;
tm = *t;
tm.tm_yday = -1;
mkt = mktime(&tm);
if (mkt == (time_t) -1) {
/* Fail unless this -1 represents
a valid time. */
struct tm tm_1;
if (!localtime_r(&mkt, &tm_1))
return NULL;
if (!(tm.tm_year == tm_1.tm_year
&& tm.tm_yday == tm_1.tm_yday
&& tm.tm_hour == tm_1.tm_hour
&& tm.tm_min == tm_1.tm_min
&& tm.tm_sec == tm_1.tm_sec))
return NULL;
}
if (TYPE_SIGNED(time_t)) {
intmax_t n = mkt;
(sprintf)(buf, "%"PRIdMAX, n);
} else {
uintmax_t n = mkt;
(sprintf)(buf, "%"PRIuMAX, n);
}
pt = strftime_add(buf, pt, ptlim);
}
continue;
case 'T':
pt = strftime_fmt("%H:%M:%S", t, pt, ptlim, warnp);
continue;
case 't':
pt = strftime_add("\t", pt, ptlim);
continue;
case 'U':
pt = strftime_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 = strftime_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 = strftime_conv(w, "%02d",
pt, ptlim);
else if (*format == 'g') {
*warnp = IN_ALL;
pt = strftime_yconv(year, base,
false, true,
pt, ptlim);
} else pt = strftime_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 = strftime_fmt("%e-%b-%Y", t, pt, ptlim, warnp);
continue;
case 'W':
pt = strftime_conv(
(t->tm_yday + DAYSPERWEEK -
(t->tm_wday ?
(t->tm_wday - 1) :
(DAYSPERWEEK - 1))) / DAYSPERWEEK,
"%02d", pt, ptlim);
continue;
case 'w':
pt = strftime_conv(t->tm_wday, "%d", pt, ptlim);
continue;
case 'X':
pt = strftime_fmt(Locale->X_fmt, t, pt, ptlim, warnp);
continue;
case 'x':
{
enum warn warn2 = IN_SOME;
pt = strftime_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 = strftime_yconv(t->tm_year, TM_YEAR_BASE,
false, true,
pt, ptlim);
continue;
case 'Y':
pt = strftime_yconv(t->tm_year, TM_YEAR_BASE,
true, true,
pt, ptlim);
continue;
case 'Z':
pt = strftime_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;
diff = t->tm_gmtoff;
negative = diff < 0;
if (diff == 0) {
negative = t->tm_zone[0] == '-';
}
if (negative) {
sign = "-";
diff = -diff;
} else sign = "+";
pt = strftime_add(sign, pt, ptlim);
diff /= SECSPERMIN;
diff = (diff / MINSPERHOUR) * 100 +
(diff % MINSPERHOUR);
pt = strftime_conv(diff, "%04d", pt, ptlim);
}
continue;
case '+':
pt = strftime_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;
}
/**
* Converts time to string, e.g.
*
* char b[64];
* int64_t sec;
* struct tm tm;
* time(&sec);
* localtime_r(&sec, &tm);
* strftime(b, sizeof(b), "%Y-%m-%dT%H:%M:%S%z", &tm); // ISO8601
* strftime(b, sizeof(b), "%a, %d %b %Y %H:%M:%S %Z", &tm); // RFC1123
*
* @return bytes copied excluding nul, or 0 on error
* @see FormatHttpDateTime()
*/
size_t
strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
{
char * p;
int saved_errno = errno;
enum warn warn = IN_NONE;
tzset();
p = strftime_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;
}
size_t
strftime_l(char *s, size_t maxsize, char const *format, struct tm const *t,
locale_t locale)
{
/* Just call strftime, as only the C locale is supported. */
return strftime(s, maxsize, format, t);
}