home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Windows Expert
/
Windows Expert.iso
/
windownt
/
awksrc.zip
/
MISSING
/
STRFTIME.C
< prev
next >
Wrap
C/C++ Source or Header
|
1992-09-09
|
14KB
|
567 lines
/*
* strftime.c
*
* Public-domain relatively quick-and-dirty implemenation of
* ANSI library routine for System V Unix systems.
*
* 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 stuff needed to implement the P1003.2 date command, add POSIX2_DATE.
* For complete POSIX semantics, add POSIX_SEMANTICS.
*
* The code for %c, %x, and %X is my best guess as to what's "appropriate".
* 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
*
* Fixes from ado@elsie.nci.nih.gov
* February 1991, May 1992
*/
#ifndef GAWK
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#endif
/* defaults: season to taste */
#define SYSV_EXT 1 /* stuff in System V ascftime routine */
#define POSIX2_DATE 1 /* stuff in Posix 1003.2 date command */
#define VMS_EXT 1 /* include %v for VMS date format */
#ifndef GAWK
#define POSIX_SEMANTICS 1 /* call tzset() if TZ changes */
#endif
#if defined(POSIX2_DATE) && ! defined(SYSV_EXT)
#define SYSV_EXT 1
#endif
#if defined(POSIX2_DATE)
#define adddecl(stuff) stuff
#else
#define adddecl(stuff)
#endif
#ifndef __STDC__
#define const /**/
extern void *malloc();
extern void *realloc();
extern void tzset();
extern char *strchr();
extern char *getenv();
static int weeknumber();
adddecl(static int iso8601wknum();)
#else
extern void *malloc(unsigned count);
extern void *realloc(void *ptr, unsigned count);
extern void tzset(void);
extern char *strchr(const char *str, int ch);
extern char *getenv(const char *v);
static int weeknumber(const struct tm *timeptr, int firstweekday);
adddecl(static int iso8601wknum(const struct tm *timeptr);)
#endif
#ifdef __GNUC__
#define inline __inline__
#else
#define inline /**/
#endif
#define range(low, item, hi) max(low, min(item, hi))
#if !defined(MSDOS) && !defined(TZNAME_MISSING)
extern char *tzname[2];
extern int daylight;
#endif
/* min --- return minimum of two numbers */
#ifndef __STDC__
static inline int
min(a, b)
int a, b;
#else
static inline int
min(int a, int b)
#endif
{
return (a < b ? a : b);
}
/* max --- return maximum of two numbers */
#ifndef __STDC__
static inline int
max(a, b)
int a, b;
#else
static inline int
max(int a, int b)
#endif
{
return (a > b ? a : b);
}
/* strftime --- produce formatted time */
#ifndef __STDC__
size_t
strftime(s, maxsize, format, timeptr)
char *s;
size_t maxsize;
const char *format;
const struct tm *timeptr;
#else
size_t
strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr)
#endif
{
char *endp = s + maxsize;
char *start = s;
char tbuf[100];
int i;
static short first = 1;
#ifdef POSIX_SEMANTICS
static char *savetz = NULL;
static int savetzlen = 0;
char *tz;
int tzlen;
#endif
/* various tables, useful in North America */
static char *days_a[] = {
"Sun", "Mon", "Tue", "Wed",
"Thu", "Fri", "Sat",
};
static char *days_l[] = {
"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday",
};
static char *months_a[] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
};
static char *months_l[] = {
"January", "February", "March", "April",
"May", "June", "July", "August", "September",
"October", "November", "December",
};
static char *ampm[] = { "AM", "PM", };
if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0)
return 0;
if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize)
return 0;
#ifndef POSIX_SEMANTICS
if (first) {
tzset();
first = 0;
}
#else /* POSIX_SEMANTICS */
tz = getenv("TZ");
tzlen = strlen(tz);
if (first) {
if (tz != NULL) {
savetz = (char *) malloc(tzlen + 1);
if (savetz != NULL) {
savetzlen = tzlen + 1;
strcpy(savetz, tz);
}
}
tzset();
first = 0;
}
/* if we have a saved TZ, and it is different, recapture and reset */
if (tz && savetz && (tz[0] != savetz[0] || strcmp(tz, savetz) != 0)) {
i = strlen(tz) + 1;
if (i > savetzlen) {
savetz = (char *) realloc(savetz, i);
if (savetz) {
savetzlen = i;
strcpy(savetz, tz);
}
} else
strcpy(savetz, tz);
tzset();
}
#endif /* POSIX_SEMANTICS */
for (; *format && s < endp - 1; format++) {
tbuf[0] = '\0';
if (*format != '%') {
*s++ = *format;
continue;
}
again:
switch (*++format) {
case '\0':
*s++ = '%';
goto out;
case '%':
*s++ = '%';
continue;
case 'a': /* abbreviated weekday name */
if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)
strcpy(tbuf, "?");
else
strcpy(tbuf, days_a[timeptr->tm_wday]);
break;
case 'A': /* full weekday name */
if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)
strcpy(tbuf, "?");
else
strcpy(tbuf, days_l[timeptr->tm_wday]);
break;
#ifdef SYSV_EXT
case 'h': /* abbreviated month name */
#endif
case 'b': /* abbreviated month name */
if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)
strcpy(tbuf, "?");
else
strcpy(tbuf, months_a[timeptr->tm_mon]);
break;
case 'B': /* full month name */
if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)
strcpy(tbuf, "?");
else
strcpy(tbuf, months_l[timeptr->tm_mon]);
break;
case 'c': /* appropriate date and time representation */
sprintf(tbuf, "%s %s %2d %02d:%02d:%02d %d",
days_a[range(0, timeptr->tm_wday, 6)],
months_a[range(0, timeptr->tm_mon, 11)],
range(1, timeptr->tm_mday, 31),
range(0, timeptr->tm_hour, 23),
range(0, timeptr->tm_min, 59),
range(0, timeptr->tm_sec, 61),
timeptr->tm_year + 1900);
break;
case 'd': /* day of the month, 01 - 31 */
i = range(1, timeptr->tm_mday, 31);
sprintf(tbuf, "%02d", i);
break;
case 'H': /* hour, 24-hour clock, 00 - 23 */
i = range(0, timeptr->tm_hour, 23);
sprintf(tbuf, "%02d", i);
break;
case 'I': /* hour, 12-hour clock, 01 - 12 */
i = range(0, timeptr->tm_hour, 23);
if (i == 0)
i = 12;
else if (i > 12)
i -= 12;
sprintf(tbuf, "%02d", i);
break;
case 'j': /* day of the year, 001 - 366 */
sprintf(tbuf, "%03d", timeptr->tm_yday + 1);
break;
case 'm': /* month, 01 - 12 */
i = range(0, timeptr->tm_mon, 11);
sprintf(tbuf, "%02d", i + 1);
break;
case 'M': /* minute, 00 - 59 */
i = range(0, timeptr->tm_min, 59);
sprintf(tbuf, "%02d", i);
break;
case 'p': /* am or pm based on 12-hour clock */
i = range(0, timeptr->tm_hour, 23);
if (i < 12)
strcpy(tbuf, ampm[0]);
else
strcpy(tbuf, ampm[1]);
break;
case 'S': /* second, 00 - 61 */
i = range(0, timeptr->tm_sec, 61);
sprintf(tbuf, "%02d", i);
break;
case 'U': /* week of year, Sunday is first day of week */
sprintf(tbuf, "%d", weeknumber(timeptr, 0));
break;
case 'w': /* weekday, Sunday == 0, 0 - 6 */
i = range(0, timeptr->tm_wday, 6);
sprintf(tbuf, "%d", i);
break;
case 'W': /* week of year, Monday is first day of week */
sprintf(tbuf, "%d", weeknumber(timeptr, 1));
break;
case 'x': /* appropriate date representation */
sprintf(tbuf, "%s %s %2d %d",
days_a[range(0, timeptr->tm_wday, 6)],
months_a[range(0, timeptr->tm_mon, 11)],
range(1, timeptr->tm_mday, 31),
timeptr->tm_year + 1900);
break;
case 'X': /* appropriate time representation */
sprintf(tbuf, "%02d:%02d:%02d",
range(0, timeptr->tm_hour, 23),
range(0, timeptr->tm_min, 59),
range(0, timeptr->tm_sec, 61));
break;
case 'y': /* year without a century, 00 - 99 */
i = timeptr->tm_year % 100;
sprintf(tbuf, "%d", i);
break;
case 'Y': /* year with century */
sprintf(tbuf, "%d", 1900 + timeptr->tm_year);
break;
case 'Z': /* time zone name or abbrevation */
i = 0;
if (
#ifndef TZNAME_MISSING
daylight &&
#endif
timeptr->tm_isdst)
i = 1;
#ifdef TZNAME_MISSING
strcpy(tbuf, timeptr->tm_zone);
#else
strcpy(tbuf, tzname[i]);
#endif
break;
#ifdef SYSV_EXT
case 'n': /* same as \n */
tbuf[0] = '\n';
tbuf[1] = '\0';
break;
case 't': /* same as \t */
tbuf[0] = '\t';
tbuf[1] = '\0';
break;
case 'D': /* date as %m/%d/%y */
strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr);
break;
case 'e': /* day of month, blank padded */
sprintf(tbuf, "%2d", range(1, timeptr->tm_mday, 31));
break;
case 'r': /* time as %I:%M:%S %p */
strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr);
break;
case 'R': /* time as %H:%M */
strftime(tbuf, sizeof tbuf, "%H:%M", timeptr);
break;
case 'T': /* time as %H:%M:%S */
strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr);
break;
#endif
#ifdef VMS_EXT
case 'v': /* date as dd-bbb-YYYY */
sprintf(tbuf, "%2d-%3.3s-%4d",
range(1, timeptr->tm_mday, 31),
months_a[range(0, timeptr->tm_mon, 11)],
timeptr->tm_year + 1900);
for (i = 3; i < 6; i++)
if (islower(tbuf[i]))
tbuf[i] = toupper(tbuf[i]);
break;
#endif
#ifdef POSIX2_DATE
case 'C':
sprintf(tbuf, "%02d", (timeptr->tm_year + 1900) / 100);
break;
case 'E':
case 'O':
/* POSIX locale extensions, ignored for now */
goto again;
case 'V': /* week of year according ISO 8601 */
#if defined(GAWK) && defined(VMS_EXT)
{
extern int do_lint;
extern void warning();
static int warned = 0;
if (! warned && do_lint) {
warned = 1;
warning(
"conversion %%V added in P1003.2/11.3; for VMS style date, use %%v");
}
}
#endif
sprintf(tbuf, "%d", iso8601wknum(timeptr));
break;
case 'u':
/* ISO 8601: Weekday as a decimal number [1 (Monday) - 7] */
sprintf(tbuf, "%d", timeptr->tm_wday == 0 ? 7 :
timeptr->tm_wday);
break;
#endif /* POSIX2_DATE */
default:
tbuf[0] = '%';
tbuf[1] = *format;
tbuf[2] = '\0';
break;
}
i = strlen(tbuf);
if (i)
if (s + i < endp - 1) {
strcpy(s, tbuf);
s += i;
} else
return 0;
}
out:
if (s < endp && *format == '\0') {
*s = '\0';
return (s - start);
} else
return 0;
}
#ifdef POSIX2_DATE
/* iso8601wknum --- compute week number according to ISO 8601 */
#ifndef __STDC__
static int
iso8601wknum(timeptr)
const struct tm *timeptr;
#else
static int
iso8601wknum(const struct tm *timeptr)
#endif
{
/*
* From 1003.2 D11.3:
* 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 week 53 of the previous year, and the
* next week is week 1.
*
* ADR: This means if Jan 1 was Monday through Thursday,
* it was week 1, otherwise week 53.
*/
int simple_wknum, jan1day, diff, ret;
/* get week number, Monday as first day of the week */
simple_wknum = weeknumber(timeptr, 1) + 1;
/*
* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov
*
* 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 == 1
* and that
* timeptr->tm_wday MOD 7 == timeptr->tm_wday
* from which it follows that. . .
*/
jan1day = (timeptr->tm_yday - 1) % 7 - timeptr->tm_wday;
if (jan1day < 0)
jan1day += 7;
/*
* If Jan 1 was a Monday through Thursday, it was in
* week 1. Otherwise it was last year's week 53, which is
* this year's week 0.
*/
if (jan1day >= 1 && jan1day <= 4)
diff = 0;
else
diff = 1;
ret = simple_wknum - diff;
if (ret == 0) /* we're in the first week of the year */
ret = 53;
return ret;
}
#endif
/* weeknumber --- figure how many weeks into the year */
/* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov */
#ifndef __STDC__
static int
weeknumber(timeptr, firstweekday)
const struct tm *timeptr;
int firstweekday;
#else
static int
weeknumber(const struct tm *timeptr, int firstweekday)
#endif
{
if (firstweekday == 0)
return (timeptr->tm_yday + 7 - timeptr->tm_wday) / 7;
else
return (timeptr->tm_yday + 7 -
(timeptr->tm_wday ? (timeptr->tm_wday - 1) : 6)) / 7;
}
#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