strftime.c

android-w.song.android.widget

		case 'x':	/* appropriate date representation */
			strftime(tbuf, sizeof tbuf, "%A %B %d %Y", timeptr);
			break;

		case 'X':	/* appropriate time representation */
			goto the_time;
			break;

		case 'y':	/* year without a century, 00 - 99 */
		year:
			i = timeptr->tm_year % 100;
			sprintf(tbuf, "%02d", i);
			break;

		case 'Y':	/* year with century */
		fullyear:
			sprintf(tbuf, "%ld", 1900L + timeptr->tm_year);
			break;

		/*
		 * From: Chip Rosenthal <[e-mail]>
		 * Date: Sun, 19 Mar 1995 00:33:29 -0600 (CST)
		 * 
		 * Warning: the %z [code] is implemented by inspecting the
		 * timezone name conditional compile settings, and
		 * inferring a method to get timezone offsets. I've tried
		 * this code on a couple of machines, but I don't doubt
		 * there is some system out there that won't like it.
		 * Maybe the easiest thing to do would be to bracket this
		 * with an #ifdef that can turn it off. The %z feature
		 * would be an admittedly obscure one that most folks can
		 * live without, but it would be a great help to those of
		 * us that muck around with various message processors.
		 */
 		case 'z':	/* time zone offset east of GMT e.g. -0600 */
 			if (timeptr->tm_isdst < 0)
 				break;
#ifdef HAVE_TM_NAME
			/*
			 * Systems with tm_name probably have tm_tzadj as
			 * secs west of GMT.  Convert to mins east of GMT.
			 */
			off = -timeptr->tm_tzadj / 60;
#else /* !HAVE_TM_NAME */
#ifdef HAVE_TM_ZONE
			/*
			 * Systems with tm_zone probably have tm_gmtoff as
			 * secs east of GMT.  Convert to mins east of GMT.
			 */
			off = timeptr->tm_gmtoff / 60;
#else /* !HAVE_TM_ZONE */
#if HAVE_TZNAME
			/*
			 * Systems with tzname[] probably have timezone as
			 * secs west of GMT.  Convert to mins east of GMT.
			 */
#  ifdef HPUX
			off = -timezone / 60;
#  else
			/* ADR: 4 August 2001, fixed this per [e-mail] */
			off = -(daylight ? altzone : timezone) / 60;
#  endif /* !HPUX */
#else /* !HAVE_TZNAME */
			gettimeofday(& tv, & zone);
			off = -zone.tz_minuteswest;
#endif /* !HAVE_TZNAME */
#endif /* !HAVE_TM_ZONE */
#endif /* !HAVE_TM_NAME */
			if (off < 0) {
				tbuf[0] = '-';
				off = -off;
			} else {
				tbuf[0] = '+';
			}
			sprintf(tbuf+1, "%02ld%02ld", off/60, off%60);
			break;

		case 'Z':	/* time zone name or abbrevation */
#ifdef HAVE_TZNAME
			i = (daylight && timeptr->tm_isdst > 0); /* 0 or 1 */
			strcpy(tbuf, tzname[i]);
#else
#ifdef HAVE_TM_ZONE
			strcpy(tbuf, timeptr->tm_zone);
#else
#ifdef HAVE_TM_NAME
			strcpy(tbuf, timeptr->tm_name);
#else
			gettimeofday(& tv, & zone);
			strcpy(tbuf, timezone(zone.tz_minuteswest,
						timeptr->tm_isdst > 0));
#endif /* HAVE_TM_NAME */
#endif /* HAVE_TM_ZONE */
#endif /* HAVE_TZNAME */
			break;

#ifdef SUNOS_EXT
		case 'k':	/* hour, 24-hour clock, blank pad */
			sprintf(tbuf, "%2d", range(0, timeptr->tm_hour, 23));
			break;

		case 'l':	/* hour, 12-hour clock, 1 - 12, blank pad */
			i = range(0, timeptr->tm_hour, 23);
			if (i == 0)
				i = 12;
			else if (i > 12)
				i -= 12;
			sprintf(tbuf, "%2d", i);
			break;
#endif

#ifdef HPUX_EXT
		case 'N':	/* Emperor/Era name */
			/* this is essentially the same as the century */
			goto century;	/* %C */

		case 'o':	/* Emperor/Era year */
			goto year;	/* %y */
#endif /* HPUX_EXT */


#ifdef VMS_EXT
		case 'v':	/* date as dd-bbb-YYYY */
			sprintf(tbuf, "%2d-%3.3s-%4ld",
				range(1, timeptr->tm_mday, 31),
				months_a[range(0, timeptr->tm_mon, 11)],
				timeptr->tm_year + 1900L);
			for (i = 3; i < 6; i++)
				if (islower(tbuf[i]))
					tbuf[i] = toupper(tbuf[i]);
			break;
#endif

		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;
}

/* isleap --- is a year a leap year? */

static int
isleap(long year)
{
	return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
}


/* 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, diff;

	/* get week number, Monday as first day of the week */
	weeknum = weeknumber(timeptr, 1);

	/*
	 * With thanks and tip of the hatlo to [e-mail]
	 *
	 * 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;
}

/* weeknumber --- figure how many weeks into the year */

/* With thanks and tip of the hatlo to [e-mail] */

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;
}

#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: [e-mail]

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
   [e-mail]
#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.
 *	[e-mail]
 *
 * 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",
	"(%%F)       full month name, var length (January..December)  %F",
	"(%%H)                          hour (24-hour clock, 00..23)  %H",
	"(%%I)                          hour (12-hour clock, 01..12)  %I",
	"(%%M)                                       minute (00..59)  %M",
	"(%%N)                                      Emporer/Era Name  %N",
	"(%%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 ( 0..12)  %l",
	"(%%m)                                        month (01..12)  %m",
	"(%%o)                                      Emporer/Era Year  %o",
	"(%%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(argc, argv)
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 */