Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
branch: trunk
Fetching contributors…

Cannot retrieve contributors at this time

1164 lines (1030 sloc) 31.5 kB
/* -*- c-file-style: "linux" -*- */
/*
* strftime.c
*
* Public-domain implementation of ANSI C library routine.
*
* It's written in old-style C for maximal portability.
* However, since I'm used to prototypes, I've included them too.
*
* If you want stuff in the System V ascftime routine, add the SYSV_EXT define.
* For extensions from SunOS, add SUNOS_EXT.
* For stuff needed to implement the P1003.2 date command, add POSIX2_DATE.
* For VMS dates, add VMS_EXT.
* For a an RFC822 time format, add MAILHEADER_EXT.
* For ISO week years, add ISO_DATE_EXT.
* For complete POSIX semantics, add POSIX_SEMANTICS.
*
* The code for %c, %x, and %X now follows the 1003.2 specification for
* the POSIX locale.
* This version ignores LOCALE information.
* It also doesn't worry about multi-byte characters.
* So there.
*
* This file is also shipped with GAWK (GNU Awk), gawk specific bits of
* code are included if GAWK is defined.
*
* Arnold Robbins
* January, February, March, 1991
* Updated March, April 1992
* Updated April, 1993
* Updated February, 1994
* Updated May, 1994
* Updated January, 1995
* Updated September, 1995
* Updated January, 1996
*
* Fixes from ado@elsie.nci.nih.gov
* February 1991, May 1992
* Fixes from Tor Lillqvist tml@tik.vtt.fi
* May, 1993
* Further fixes from ado@elsie.nci.nih.gov
* February 1994
* %z code from chip@chinacat.unicom.com
* Applied September 1995
* %V code fixed (again) and %G, %g added,
* January 1996
*/
#include "ruby/ruby.h"
#include "ruby/encoding.h"
#include "timev.h"
#ifndef GAWK
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <errno.h>
#endif
#if defined(TM_IN_SYS_TIME) || !defined(GAWK)
#include <sys/types.h>
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#endif
#include <math.h>
/* defaults: season to taste */
#define SYSV_EXT 1 /* stuff in System V ascftime routine */
#define SUNOS_EXT 1 /* stuff in SunOS strftime routine */
#define POSIX2_DATE 1 /* stuff in Posix 1003.2 date command */
#define VMS_EXT 1 /* include %v for VMS date format */
#define MAILHEADER_EXT 1 /* add %z for HHMM format */
#define ISO_DATE_EXT 1 /* %G and %g for year of ISO week */
#if defined(ISO_DATE_EXT)
#if ! defined(POSIX2_DATE)
#define POSIX2_DATE 1
#endif
#endif
#if defined(POSIX2_DATE)
#if ! defined(SYSV_EXT)
#define SYSV_EXT 1
#endif
#if ! defined(SUNOS_EXT)
#define SUNOS_EXT 1
#endif
#endif
#if defined(POSIX2_DATE)
#define adddecl(stuff) stuff
#else
#define adddecl(stuff)
#endif
#undef strchr /* avoid AIX weirdness */
#if !defined __STDC__ && !defined _WIN32
#define const /**/
static int weeknumber();
adddecl(static int iso8601wknum();)
static int weeknumber_v();
adddecl(static int iso8601wknum_v();)
#else
static int weeknumber(const struct tm *timeptr, int firstweekday);
adddecl(static int iso8601wknum(const struct tm *timeptr);)
static int weeknumber_v(const struct vtm *vtm, int firstweekday);
adddecl(static int iso8601wknum_v(const struct vtm *vtm);)
#endif
#ifdef STDC_HEADERS
#include <stdlib.h>
#include <string.h>
#else
extern void *malloc();
extern void *realloc();
extern char *getenv();
extern char *strchr();
#endif
#define range(low, item, hi) max((low), min((item), (hi)))
#undef min /* just in case */
/* min --- return minimum of two numbers */
static inline int
min(int a, int b)
{
return (a < b ? a : b);
}
#undef max /* also, just in case */
/* max --- return maximum of two numbers */
static inline int
max(int a, int b)
{
return (a > b ? a : b);
}
#ifdef NO_STRING_LITERAL_CONCATENATION
#error No string literal concatenation
#endif
#define add(x,y) (rb_funcall((x), '+', 1, (y)))
#define sub(x,y) (rb_funcall((x), '-', 1, (y)))
#define mul(x,y) (rb_funcall((x), '*', 1, (y)))
#define quo(x,y) (rb_funcall((x), rb_intern("quo"), 1, (y)))
#define div(x,y) (rb_funcall((x), rb_intern("div"), 1, (y)))
#define mod(x,y) (rb_funcall((x), '%', 1, (y)))
/* strftime --- produce formatted time */
/*
* enc is the encoding of the format. It is used as the encoding of resulted
* string, but the name of the month and weekday are always US-ASCII. So it
* is only used for the timezone name on Windows.
*/
static size_t
rb_strftime_with_timespec(char *s, size_t maxsize, const char *format, rb_encoding *enc, const struct vtm *vtm, VALUE timev, struct timespec *ts, int gmt)
{
const char *const endp = s + maxsize;
const char *const start = s;
const char *sp, *tp;
#define TBUFSIZE 100
auto char tbuf[TBUFSIZE];
long off;
ptrdiff_t i;
int w;
long y;
int precision, flags, colons;
char padding;
enum {LEFT, CHCASE, LOWER, UPPER};
#define BIT_OF(n) (1U<<(n))
#ifdef MAILHEADER_EXT
int sign;
#endif
/* various tables, useful in North America */
static const char days_l[][10] = {
"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday",
};
static const char months_l[][10] = {
"January", "February", "March", "April",
"May", "June", "July", "August", "September",
"October", "November", "December",
};
static const char ampm[][3] = { "AM", "PM", };
if (s == NULL || format == NULL || vtm == NULL || maxsize == 0)
return 0;
/* quick check if we even need to bother */
if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize) {
err:
errno = ERANGE;
return 0;
}
if (enc && (enc == rb_usascii_encoding() ||
enc == rb_ascii8bit_encoding() || enc == rb_locale_encoding())) {
enc = NULL;
}
for (; *format && s < endp - 1; format++) {
#define FLAG_FOUND() do { \
if (precision > 0) \
goto unknown; \
} while (0)
#define NEEDS(n) do if (s >= endp || (n) >= endp - s - 1) goto err; while (0)
#define FILL_PADDING(i) do { \
if (!(flags & BIT_OF(LEFT)) && precision > (i)) { \
NEEDS(precision); \
memset(s, padding ? padding : ' ', precision - (i)); \
s += precision - (i); \
} \
else { \
NEEDS(i); \
} \
} while (0);
#define FMT(def_pad, def_prec, fmt, val) \
do { \
int l; \
if (precision <= 0) precision = (def_prec); \
if (flags & BIT_OF(LEFT)) precision = 1; \
l = snprintf(s, endp - s, \
((padding == '0' || (!padding && (def_pad) == '0')) ? "%0*"fmt : "%*"fmt), \
precision, (val)); \
if (l < 0) goto err; \
s += l; \
} while (0)
#define STRFTIME(fmt) \
do { \
i = rb_strftime_with_timespec(s, endp - s, (fmt), enc, vtm, timev, ts, gmt); \
if (!i) return 0; \
if (precision > i) {\
NEEDS(precision); \
memmove(s + precision - i, s, i);\
memset(s, padding ? padding : ' ', precision - i); \
s += precision; \
}\
else s += i; \
} while (0)
#define FMTV(def_pad, def_prec, fmt, val) \
do { \
VALUE tmp = (val); \
if (FIXNUM_P(tmp)) { \
FMT((def_pad), (def_prec), "l"fmt, FIX2LONG(tmp)); \
} \
else { \
VALUE args[2], result; \
size_t l; \
if (precision <= 0) precision = (def_prec); \
if (flags & BIT_OF(LEFT)) precision = 1; \
args[0] = INT2FIX(precision); \
args[1] = (val); \
if (padding == '0' || (!padding && (def_pad) == '0')) \
result = rb_str_format(2, args, rb_str_new2("%0*"fmt)); \
else \
result = rb_str_format(2, args, rb_str_new2("%*"fmt)); \
l = strlcpy(s, StringValueCStr(result), endp-s); \
if ((size_t)(endp-s) <= l) \
goto err; \
s += l; \
} \
} while (0)
if (*format != '%') {
*s++ = *format;
continue;
}
tp = tbuf;
sp = format;
precision = -1;
flags = 0;
padding = 0;
colons = 0;
again:
switch (*++format) {
case '\0':
format--;
goto unknown;
case '%':
FILL_PADDING(1);
*s++ = '%';
continue;
case 'a': /* abbreviated weekday name */
if (flags & BIT_OF(CHCASE)) {
flags &= ~(BIT_OF(LOWER)|BIT_OF(CHCASE));
flags |= BIT_OF(UPPER);
}
if (vtm->wday < 0 || vtm->wday > 6)
i = 1, tp = "?";
else
i = 3, tp = days_l[vtm->wday];
break;
case 'A': /* full weekday name */
if (flags & BIT_OF(CHCASE)) {
flags &= ~(BIT_OF(LOWER)|BIT_OF(CHCASE));
flags |= BIT_OF(UPPER);
}
if (vtm->wday < 0 || vtm->wday > 6)
i = 1, tp = "?";
else
i = strlen(tp = days_l[vtm->wday]);
break;
#ifdef SYSV_EXT
case 'h': /* abbreviated month name */
#endif
case 'b': /* abbreviated month name */
if (flags & BIT_OF(CHCASE)) {
flags &= ~(BIT_OF(LOWER)|BIT_OF(CHCASE));
flags |= BIT_OF(UPPER);
}
if (vtm->mon < 1 || vtm->mon > 12)
i = 1, tp = "?";
else
i = 3, tp = months_l[vtm->mon-1];
break;
case 'B': /* full month name */
if (flags & BIT_OF(CHCASE)) {
flags &= ~(BIT_OF(LOWER)|BIT_OF(CHCASE));
flags |= BIT_OF(UPPER);
}
if (vtm->mon < 1 || vtm->mon > 12)
i = 1, tp = "?";
else
i = strlen(tp = months_l[vtm->mon-1]);
break;
case 'c': /* appropriate date and time representation */
STRFTIME("%a %b %e %H:%M:%S %Y");
continue;
case 'd': /* day of the month, 01 - 31 */
i = range(1, vtm->mday, 31);
FMT('0', 2, "d", (int)i);
continue;
case 'H': /* hour, 24-hour clock, 00 - 23 */
i = range(0, vtm->hour, 23);
FMT('0', 2, "d", (int)i);
continue;
case 'I': /* hour, 12-hour clock, 01 - 12 */
i = range(0, vtm->hour, 23);
if (i == 0)
i = 12;
else if (i > 12)
i -= 12;
FMT('0', 2, "d", (int)i);
continue;
case 'j': /* day of the year, 001 - 366 */
i = range(1, vtm->yday, 366);
FMT('0', 3, "d", (int)i);
continue;
case 'm': /* month, 01 - 12 */
i = range(1, vtm->mon, 12);
FMT('0', 2, "d", (int)i);
continue;
case 'M': /* minute, 00 - 59 */
i = range(0, vtm->min, 59);
FMT('0', 2, "d", (int)i);
continue;
case 'p': /* AM or PM based on 12-hour clock */
case 'P': /* am or pm based on 12-hour clock */
if ((*format == 'p' && (flags & BIT_OF(CHCASE))) ||
(*format == 'P' && !(flags & (BIT_OF(CHCASE)|BIT_OF(UPPER))))) {
flags &= ~(BIT_OF(UPPER)|BIT_OF(CHCASE));
flags |= BIT_OF(LOWER);
}
i = range(0, vtm->hour, 23);
if (i < 12)
tp = ampm[0];
else
tp = ampm[1];
i = 2;
break;
case 's':
if (ts) {
time_t sec = ts->tv_sec;
if (~(time_t)0 <= 0)
FMT('0', 1, PRI_TIMET_PREFIX"d", sec);
else
FMT('0', 1, PRI_TIMET_PREFIX"u", sec);
}
else {
VALUE sec = div(timev, INT2FIX(1));
FMTV('0', 1, "d", sec);
}
continue;
case 'S': /* second, 00 - 60 */
i = range(0, vtm->sec, 60);
FMT('0', 2, "d", (int)i);
continue;
case 'U': /* week of year, Sunday is first day of week */
FMT('0', 2, "d", weeknumber_v(vtm, 0));
continue;
case 'w': /* weekday, Sunday == 0, 0 - 6 */
i = range(0, vtm->wday, 6);
FMT('0', 1, "d", (int)i);
continue;
case 'W': /* week of year, Monday is first day of week */
FMT('0', 2, "d", weeknumber_v(vtm, 1));
continue;
case 'x': /* appropriate date representation */
STRFTIME("%m/%d/%y");
continue;
case 'X': /* appropriate time representation */
STRFTIME("%H:%M:%S");
continue;
case 'y': /* year without a century, 00 - 99 */
i = NUM2INT(mod(vtm->year, INT2FIX(100)));
FMT('0', 2, "d", (int)i);
continue;
case 'Y': /* year with century */
if (FIXNUM_P(vtm->year)) {
long y = FIX2LONG(vtm->year);
FMT('0', 0 <= y ? 4 : 5, "ld", y);
}
else {
FMTV('0', 4, "d", vtm->year);
}
continue;
#ifdef MAILHEADER_EXT
case 'z': /* time zone offset east of GMT e.g. -0600 */
if (gmt) {
off = 0;
}
else {
off = NUM2LONG(rb_funcall(vtm->utc_offset, rb_intern("round"), 0));
}
if (off < 0) {
off = -off;
sign = -1;
} else {
sign = +1;
}
switch (colons) {
case 0: /* %z -> +hhmm */
precision = precision <= 5 ? 2 : precision-3;
NEEDS(precision + 3);
break;
case 1: /* %:z -> +hh:mm */
precision = precision <= 6 ? 2 : precision-4;
NEEDS(precision + 4);
break;
case 2: /* %::z -> +hh:mm:ss */
precision = precision <= 9 ? 2 : precision-7;
NEEDS(precision + 7);
break;
case 3: /* %:::z -> +hh[:mm[:ss]] */
if (off % 3600 == 0) {
precision = precision <= 3 ? 2 : precision-1;
NEEDS(precision + 3);
}
else if (off % 60 == 0) {
precision = precision <= 6 ? 2 : precision-4;
NEEDS(precision + 4);
}
else {
precision = precision <= 9 ? 2 : precision-7;
NEEDS(precision + 9);
}
break;
default:
format--;
goto unknown;
}
i = snprintf(s, endp - s, (padding == ' ' ? "%+*ld" : "%+.*ld"),
precision + 1, sign * (off / 3600));
if (i < 0) goto err;
if (sign < 0 && off < 3600) {
*(padding == ' ' ? s + i - 2 : s) = '-';
}
s += i;
off = off % 3600;
if (colons == 3 && off == 0)
continue;
if (1 <= colons)
*s++ = ':';
i = snprintf(s, endp - s, "%02d", (int)(off / 60));
if (i < 0) goto err;
s += i;
off = off % 60;
if (colons == 3 && off == 0)
continue;
if (2 <= colons) {
*s++ = ':';
i = snprintf(s, endp - s, "%02d", (int)off);
if (i < 0) goto err;
s += i;
}
continue;
#endif /* MAILHEADER_EXT */
case 'Z': /* time zone name or abbreviation */
if (flags & BIT_OF(CHCASE)) {
flags &= ~(BIT_OF(UPPER)|BIT_OF(CHCASE));
flags |= BIT_OF(LOWER);
}
if (gmt) {
i = 3;
tp = "UTC";
break;
}
if (vtm->zone == NULL) {
i = 0;
}
else {
tp = vtm->zone;
if (enc) {
for (i = 0; i < TBUFSIZE && tp[i]; i++) {
if ((unsigned char)tp[i] > 0x7F) {
VALUE str = rb_str_conv_enc_opts(rb_str_new_cstr(tp), rb_locale_encoding(), enc, ECONV_UNDEF_REPLACE|ECONV_INVALID_REPLACE, Qnil);
i = strlcpy(tbuf, RSTRING_PTR(str), TBUFSIZE);
tp = tbuf;
break;
}
}
}
else
i = strlen(tp);
}
break;
#ifdef SYSV_EXT
case 'n': /* same as \n */
FILL_PADDING(1);
*s++ = '\n';
continue;
case 't': /* same as \t */
FILL_PADDING(1);
*s++ = '\t';
continue;
case 'D': /* date as %m/%d/%y */
STRFTIME("%m/%d/%y");
continue;
case 'e': /* day of month, blank padded */
FMT(' ', 2, "d", range(1, vtm->mday, 31));
continue;
case 'r': /* time as %I:%M:%S %p */
STRFTIME("%I:%M:%S %p");
continue;
case 'R': /* time as %H:%M */
STRFTIME("%H:%M");
continue;
case 'T': /* time as %H:%M:%S */
STRFTIME("%H:%M:%S");
continue;
#endif
#ifdef SUNOS_EXT
case 'k': /* hour, 24-hour clock, blank pad */
i = range(0, vtm->hour, 23);
FMT(' ', 2, "d", (int)i);
continue;
case 'l': /* hour, 12-hour clock, 1 - 12, blank pad */
i = range(0, vtm->hour, 23);
if (i == 0)
i = 12;
else if (i > 12)
i -= 12;
FMT(' ', 2, "d", (int)i);
continue;
#endif
#ifdef VMS_EXT
case 'v': /* date as dd-bbb-YYYY */
STRFTIME("%e-%^b-%4Y");
continue;
#endif
#ifdef POSIX2_DATE
case 'C':
FMTV('0', 2, "d", div(vtm->year, INT2FIX(100)));
continue;
case 'E':
/* POSIX locale extensions, ignored for now */
if (!format[1] || !strchr("cCxXyY", format[1]))
goto unknown;
goto again;
case 'O':
/* POSIX locale extensions, ignored for now */
if (!format[1] || !strchr("deHkIlmMSuUVwWy", format[1]))
goto unknown;
goto again;
case 'V': /* week of year according ISO 8601 */
FMT('0', 2, "d", iso8601wknum_v(vtm));
continue;
case 'u':
/* ISO 8601: Weekday as a decimal number [1 (Monday) - 7] */
FMT('0', 1, "d", vtm->wday == 0 ? 7 : vtm->wday);
continue;
#endif /* POSIX2_DATE */
#ifdef ISO_DATE_EXT
case 'G':
case 'g':
/*
* Year of ISO week.
*
* If it's December but the ISO week number is one,
* that week is in next year.
* If it's January but the ISO week number is 52 or
* 53, that week is in last year.
* Otherwise, it's this year.
*/
{
VALUE yv = vtm->year;
w = iso8601wknum_v(vtm);
if (vtm->mon == 12 && w == 1)
yv = add(yv, INT2FIX(1));
else if (vtm->mon == 1 && w >= 52)
yv = sub(yv, INT2FIX(1));
if (*format == 'G') {
if (FIXNUM_P(yv)) {
const long y = FIX2LONG(yv);
FMT('0', 0 <= y ? 4 : 5, "ld", y);
}
else {
FMTV('0', 4, "d", yv);
}
}
else {
yv = mod(yv, INT2FIX(100));
y = FIX2LONG(yv);
FMT('0', 2, "ld", y);
}
continue;
}
#endif /* ISO_DATE_EXT */
case 'L':
w = 3;
goto subsec;
case 'N':
/*
* fractional second digits. default is 9 digits
* (nanosecond).
*
* %3N millisecond (3 digits)
* %6N microsecond (6 digits)
* %9N nanosecond (9 digits)
*/
w = 9;
subsec:
if (precision <= 0) {
precision = w;
}
NEEDS(precision);
if (ts) {
long subsec = ts->tv_nsec;
if (9 < precision) {
snprintf(s, endp - s, "%09ld", subsec);
memset(s+9, '0', precision-9);
s += precision;
}
else {
int i;
for (i = 0; i < 9-precision; i++)
subsec /= 10;
snprintf(s, endp - s, "%0*ld", precision, subsec);
s += precision;
}
}
else {
VALUE subsec = mod(timev, INT2FIX(1));
int ww;
long n;
ww = precision;
while (9 <= ww) {
subsec = mul(subsec, INT2FIX(1000000000));
ww -= 9;
}
n = 1;
for (; 0 < ww; ww--)
n *= 10;
if (n != 1)
subsec = mul(subsec, INT2FIX(n));
subsec = div(subsec, INT2FIX(1));
if (FIXNUM_P(subsec)) {
(void)snprintf(s, endp - s, "%0*ld", precision, FIX2LONG(subsec));
s += precision;
}
else {
VALUE args[2], result;
args[0] = INT2FIX(precision);
args[1] = subsec;
result = rb_str_format(2, args, rb_str_new2("%0*d"));
(void)strlcpy(s, StringValueCStr(result), endp-s);
s += precision;
}
}
continue;
case 'F': /* Equivalent to %Y-%m-%d */
STRFTIME("%Y-%m-%d");
continue;
case '-':
FLAG_FOUND();
flags |= BIT_OF(LEFT);
padding = precision = 0;
goto again;
case '^':
FLAG_FOUND();
flags |= BIT_OF(UPPER);
goto again;
case '#':
FLAG_FOUND();
flags |= BIT_OF(CHCASE);
goto again;
case '_':
FLAG_FOUND();
padding = ' ';
goto again;
case ':':
{
size_t l = strspn(format, ":");
if (l > 3 || format[l] != 'z') goto unknown;
colons = (int)l;
format += l - 1;
}
goto again;
case '0':
padding = '0';
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
{
char *e;
precision = (int)strtoul(format, &e, 10);
format = e - 1;
goto again;
}
default:
unknown:
i = format - sp + 1;
tp = sp;
precision = -1;
flags = 0;
padding = 0;
colons = 0;
break;
}
if (i) {
FILL_PADDING(i);
memcpy(s, tp, i);
switch (flags & (BIT_OF(UPPER)|BIT_OF(LOWER))) {
case BIT_OF(UPPER):
do {
if (ISLOWER(*s)) *s = TOUPPER(*s);
} while (s++, --i);
break;
case BIT_OF(LOWER):
do {
if (ISUPPER(*s)) *s = TOLOWER(*s);
} while (s++, --i);
break;
default:
s += i;
break;
}
}
}
if (s >= endp) {
goto err;
}
if (*format == '\0') {
*s = '\0';
return (s - start);
} else
return 0;
}
size_t
rb_strftime(char *s, size_t maxsize, const char *format, rb_encoding *enc, const struct vtm *vtm, VALUE timev, int gmt)
{
return rb_strftime_with_timespec(s, maxsize, format, enc, vtm, timev, NULL, gmt);
}
size_t
rb_strftime_timespec(char *s, size_t maxsize, const char *format, rb_encoding *enc, const struct vtm *vtm, struct timespec *ts, int gmt)
{
return rb_strftime_with_timespec(s, maxsize, format, enc, vtm, Qnil, ts, gmt);
}
/* isleap --- is a year a leap year? */
static int
isleap(long year)
{
return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
}
static void
vtm2tm_noyear(const struct vtm *vtm, struct tm *result)
{
struct tm tm;
/* for isleap() in iso8601wknum. +100 is -1900 (mod 400). */
tm.tm_year = FIX2INT(mod(vtm->year, INT2FIX(400))) + 100;
tm.tm_mon = vtm->mon-1;
tm.tm_mday = vtm->mday;
tm.tm_hour = vtm->hour;
tm.tm_min = vtm->min;
tm.tm_sec = vtm->sec;
tm.tm_wday = vtm->wday;
tm.tm_yday = vtm->yday-1;
tm.tm_isdst = vtm->isdst;
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
tm.tm_gmtoff = NUM2LONG(vtm->utc_offset);
#endif
#if defined(HAVE_TM_ZONE)
tm.tm_zone = (char *)vtm->zone;
#endif
*result = tm;
}
#ifdef POSIX2_DATE
/* iso8601wknum --- compute week number according to ISO 8601 */
static int
iso8601wknum(const struct tm *timeptr)
{
/*
* From 1003.2:
* If the week (Monday to Sunday) containing January 1
* has four or more days in the new year, then it is week 1;
* otherwise it is the highest numbered week of the previous
* year (52 or 53), and the next week is week 1.
*
* ADR: This means if Jan 1 was Monday through Thursday,
* it was week 1, otherwise week 52 or 53.
*
* XPG4 erroneously included POSIX.2 rationale text in the
* main body of the standard. Thus it requires week 53.
*/
int weeknum, jan1day;
/* get week number, Monday as first day of the week */
weeknum = weeknumber(timeptr, 1);
/*
* With thanks and tip of the hatlo to tml@tik.vtt.fi
*
* What day of the week does January 1 fall on?
* We know that
* (timeptr->tm_yday - jan1.tm_yday) MOD 7 ==
* (timeptr->tm_wday - jan1.tm_wday) MOD 7
* and that
* jan1.tm_yday == 0
* and that
* timeptr->tm_wday MOD 7 == timeptr->tm_wday
* from which it follows that. . .
*/
jan1day = timeptr->tm_wday - (timeptr->tm_yday % 7);
if (jan1day < 0)
jan1day += 7;
/*
* If Jan 1 was a Monday through Thursday, it was in
* week 1. Otherwise it was last year's highest week, which is
* this year's week 0.
*
* What does that mean?
* If Jan 1 was Monday, the week number is exactly right, it can
* never be 0.
* If it was Tuesday through Thursday, the weeknumber is one
* less than it should be, so we add one.
* Otherwise, Friday, Saturday or Sunday, the week number is
* OK, but if it is 0, it needs to be 52 or 53.
*/
switch (jan1day) {
case 1: /* Monday */
break;
case 2: /* Tuesday */
case 3: /* Wednesday */
case 4: /* Thursday */
weeknum++;
break;
case 5: /* Friday */
case 6: /* Saturday */
case 0: /* Sunday */
if (weeknum == 0) {
#ifdef USE_BROKEN_XPG4
/* XPG4 (as of March 1994) says 53 unconditionally */
weeknum = 53;
#else
/* get week number of last week of last year */
struct tm dec31ly; /* 12/31 last year */
dec31ly = *timeptr;
dec31ly.tm_year--;
dec31ly.tm_mon = 11;
dec31ly.tm_mday = 31;
dec31ly.tm_wday = (jan1day == 0) ? 6 : jan1day - 1;
dec31ly.tm_yday = 364 + isleap(dec31ly.tm_year + 1900L);
weeknum = iso8601wknum(& dec31ly);
#endif
}
break;
}
if (timeptr->tm_mon == 11) {
/*
* The last week of the year
* can be in week 1 of next year.
* Sigh.
*
* This can only happen if
* M T W
* 29 30 31
* 30 31
* 31
*/
int wday, mday;
wday = timeptr->tm_wday;
mday = timeptr->tm_mday;
if ( (wday == 1 && (mday >= 29 && mday <= 31))
|| (wday == 2 && (mday == 30 || mday == 31))
|| (wday == 3 && mday == 31))
weeknum = 1;
}
return weeknum;
}
static int
iso8601wknum_v(const struct vtm *vtm)
{
struct tm tm;
vtm2tm_noyear(vtm, &tm);
return iso8601wknum(&tm);
}
#endif
/* weeknumber --- figure how many weeks into the year */
/* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov */
static int
weeknumber(const struct tm *timeptr, int firstweekday)
{
int wday = timeptr->tm_wday;
int ret;
if (firstweekday == 1) {
if (wday == 0) /* sunday */
wday = 6;
else
wday--;
}
ret = ((timeptr->tm_yday + 7 - wday) / 7);
if (ret < 0)
ret = 0;
return ret;
}
static int
weeknumber_v(const struct vtm *vtm, int firstweekday)
{
struct tm tm;
vtm2tm_noyear(vtm, &tm);
return weeknumber(&tm, firstweekday);
}
#if 0
/* ADR --- I'm loathe to mess with ado's code ... */
Date: Wed, 24 Apr 91 20:54:08 MDT
From: Michal Jaegermann <audfax!emory!vm.ucs.UAlberta.CA!NTOMCZAK>
To: arnold@audiofax.com
Hi Arnold,
in a process of fixing of strftime() in libraries on Atari ST I grabbed
some pieces of code from your own strftime. When doing that it came
to mind that your weeknumber() function compiles a little bit nicer
in the following form:
/*
* firstweekday is 0 if starting in Sunday, non-zero if in Monday
*/
{
return (timeptr->tm_yday - timeptr->tm_wday +
(firstweekday ? (timeptr->tm_wday ? 8 : 1) : 7)) / 7;
}
How nicer it depends on a compiler, of course, but always a tiny bit.
Cheers,
Michal
ntomczak@vm.ucs.ualberta.ca
#endif
#ifdef TEST_STRFTIME
/*
* NAME:
* tst
*
* SYNOPSIS:
* tst
*
* DESCRIPTION:
* "tst" is a test driver for the function "strftime".
*
* OPTIONS:
* None.
*
* AUTHOR:
* Karl Vogel
* Control Data Systems, Inc.
* vogelke@c-17igp.wpafb.af.mil
*
* BUGS:
* None noticed yet.
*
* COMPILE:
* cc -o tst -DTEST_STRFTIME strftime.c
*/
/* ADR: I reformatted this to my liking, and deleted some unneeded code. */
#ifndef NULL
#include <stdio.h>
#endif
#include <sys/time.h>
#include <string.h>
#define MAXTIME 132
/*
* Array of time formats.
*/
static char *array[] =
{
"(%%A) full weekday name, var length (Sunday..Saturday) %A",
"(%%B) full month name, var length (January..December) %B",
"(%%C) Century %C",
"(%%D) date (%%m/%%d/%%y) %D",
"(%%E) Locale extensions (ignored) %E",
"(%%H) hour (24-hour clock, 00..23) %H",
"(%%I) hour (12-hour clock, 01..12) %I",
"(%%M) minute (00..59) %M",
"(%%O) Locale extensions (ignored) %O",
"(%%R) time, 24-hour (%%H:%%M) %R",
"(%%S) second (00..60) %S",
"(%%T) time, 24-hour (%%H:%%M:%%S) %T",
"(%%U) week of year, Sunday as first day of week (00..53) %U",
"(%%V) week of year according to ISO 8601 %V",
"(%%W) week of year, Monday as first day of week (00..53) %W",
"(%%X) appropriate locale time representation (%H:%M:%S) %X",
"(%%Y) year with century (1970...) %Y",
"(%%Z) timezone (EDT), or blank if timezone not determinable %Z",
"(%%a) locale's abbreviated weekday name (Sun..Sat) %a",
"(%%b) locale's abbreviated month name (Jan..Dec) %b",
"(%%c) full date (Sat Nov 4 12:02:33 1989)%n%t%t%t %c",
"(%%d) day of the month (01..31) %d",
"(%%e) day of the month, blank-padded ( 1..31) %e",
"(%%h) should be same as (%%b) %h",
"(%%j) day of the year (001..366) %j",
"(%%k) hour, 24-hour clock, blank pad ( 0..23) %k",
"(%%l) hour, 12-hour clock, blank pad ( 1..12) %l",
"(%%m) month (01..12) %m",
"(%%p) locale's AM or PM based on 12-hour clock %p",
"(%%r) time, 12-hour (same as %%I:%%M:%%S %%p) %r",
"(%%u) ISO 8601: Weekday as decimal number [1 (Monday) - 7] %u",
"(%%v) VMS date (dd-bbb-YYYY) %v",
"(%%w) day of week (0..6, Sunday == 0) %w",
"(%%x) appropriate locale date representation %x",
"(%%y) last two digits of year (00..99) %y",
"(%%z) timezone offset east of GMT as HHMM (e.g. -0500) %z",
(char *) NULL
};
/* main routine. */
int
main(int argc, char **argv)
{
long time();
char *next;
char string[MAXTIME];
int k;
int length;
struct tm *tm;
long clock;
/* Call the function. */
clock = time((long *) 0);
tm = localtime(&clock);
for (k = 0; next = array[k]; k++) {
length = strftime(string, MAXTIME, next, tm);
printf("%s\n", string);
}
exit(0);
}
#endif /* TEST_STRFTIME */
Jump to Line
Something went wrong with that request. Please try again.