/* exp_strp.c - functions for exp_timestamp */

/*

 * 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 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 <arnold@skeeve.atl.ga.us>

 * January, February, March, 1991

 * Updated March, April 1992

 * Updated April, 1993

 * Updated February, 1994

 * Updated May, 1994

 * Updated January 1995

 * Updated September 1995

 *

 * 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

 *

 *

 * Modified by Don Libes for Expect, 10/93 and 12/95.

 * Forced POSIX semantics.

 * Replaced inline/min/max stuff with a single range function.

 * Removed tzset stuff.

 * Commented out tzname stuff.

 *

 * According to Arnold, the current version of this code can ftp'd from

 * ftp.mathcs.emory.edu:/pub/arnold/strftime.shar.gz

 *

 */

#include "expect_cf.h"

#include "tcl.h"

#include <stdio.h>

#include <ctype.h>

#include "string.h"

/* according to Karl Vogel, time.h is insufficient on Pyramid */

/* following is recommended by autoconf */

#ifdef TIME_WITH_SYS_TIME

# include <sys/time.h>

# include <time.h>

#else

# ifdef HAVE_SYS_TIME_H

#  include <sys/time.h>

# else

#  include <time.h>

# endif

#endif

#include <sys/types.h>

#define SYSV_EXT	1	/* stuff in System V ascftime routine */

#define POSIX2_DATE	1	/* stuff in Posix 1003.2 date command */

#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 char *getenv();

static int weeknumber();

adddecl(static int iso8601wknum();)

#else

#ifndef strchr

extern char *strchr(const char *str, int ch);

#endif

extern char *getenv(const char *v);

static int weeknumber(const struct tm *timeptr, int firstweekday);

adddecl(static int iso8601wknum(const struct tm *timeptr);)

#endif

/* attempt to use strftime to compute timezone, else fallback to */

/* less portable ways */

#if !defined(HAVE_STRFTIME)

# if defined(HAVE_SV_TIMEZONE)

extern char *tzname[2];

extern int daylight;

# else

#  if defined(HAVE_TIMEZONE)

char           *

zone_name (tp)

struct tm      *tp;

{

	char           *timezone ();

	struct timeval  tv;

	struct timezone tz;

	gettimeofday (&tv, &tz;;

	return timezone (tz.tz_minuteswest, tp->tm_isdst);

}

#  endif /* HAVE_TIMEZONE */

# endif /* HAVE_SV_TIMEZONE */

#endif /* HAVE_STRFTIME */

static int

range(low,item,hi)

int low, item, hi;

{

	if (item < low) return low;

	if (item > hi) return hi;

	return item;

}

/* strftime --- produce formatted time */

void

/*size_t*/

#ifndef __STDC__

exp_strftime(/*s,*/ format, timeptr, dstring)

/*char *s;*/

char *format;

const struct tm *timeptr;

Tcl_DString *dstring;

#else

/*exp_strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr)*/

exp_strftime(char *format, const struct tm *timeptr,Tcl_DString *dstring)

#endif

{

	int copied;	/* used to suppress copying when called recursively */

#if 0

	char *endp = s + maxsize;

	char *start = s;

#endif

	char *percentptr;

	char tbuf[100];

	int i;

	/* 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", };

/*	for (; *format && s < endp - 1; format++) {*/

	for (; *format ; format++) {

		tbuf[0] = '\0';

		copied = 0;		/* has not been copied yet */

		percentptr = strchr(format,'%');

		if (percentptr == 0) {

			Tcl_DStringAppend(dstring,format,-1);

			goto out;

		} else if (percentptr != format) {

			Tcl_DStringAppend(dstring,format,percentptr - format);

			format = percentptr;

	        }

#if 0

		if (*format != '%') {

			*s++ = *format;

			continue;

		}

#endif

	again:

		switch (*++format) {

		case '\0':

			Tcl_DStringAppend(dstring,"%",1);

#if 0

			*s++ = '%';

#endif

			goto out;

		case '%':

			Tcl_DStringAppend(dstring,"%",1);

			copied = 1;

			break;

#if 0

			*s++ = '%';

			continue;

#endif

		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, "%02d", 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, "%02d", 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, "%02d", i);

			break;

		case 'Y':	/* year with century */

			sprintf(tbuf, "%d", 1900 + timeptr->tm_year);

			break;

		case 'Z':	/* time zone name or abbrevation */

#if defined(HAVE_STRFTIME)

			strftime(tbuf,sizeof tbuf,"%Z",timeptr);

#else

# if defined(HAVE_SV_TIMEZONE)

			i = 0;

			if (daylight && timeptr->tm_isdst)

				i = 1;

			strcpy(tbuf, tzname[i]);

# else

			strcpy(tbuf, zone_name (timeptr));

#  if defined(HAVE_TIMEZONE)

#  endif /* HAVE_TIMEZONE */

			/* no timezone available */

			/* feel free to add others here */

# endif /* HAVE_SV_TIMEZONE */

#endif /* HAVE STRFTIME */

			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 */

			exp_strftime("%m/%d/%y", timeptr, dstring);

			copied = 1;

/*			exp_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 */

			exp_strftime("%I:%M:%S %p", timeptr, dstring);

			copied = 1;

/*			exp_strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr);*/

			break;

		case 'R':	/* time as %H:%M */

			exp_strftime("%H:%M", timeptr, dstring);

			copied = 1;

/*			exp_strftime(tbuf, sizeof tbuf, "%H:%M", timeptr);*/

			break;

		case 'T':	/* time as %H:%M:%S */

			exp_strftime("%H:%M:%S", timeptr, dstring);

			copied = 1;

/*			exp_strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr);*/

			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 */

			sprintf(tbuf, "%02d", 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;

		}

		if (!copied)

			Tcl_DStringAppend(dstring,tbuf,-1);

#if 0

		i = strlen(tbuf);

		if (i) {

			if (s + i < endp - 1) {

				strcpy(s, tbuf);

				s += i;

			} else

				return 0;

#endif

	}

out:;

#if 0

	if (s < endp && *format == '\0') {

		*s = '\0';

		return (s - start);

	} else

		return 0;

#endif

}

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

#ifndef __STDC__

static int

isleap(year)

int year;

#else

static int

isleap(int year)

#endif

{

	return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 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:

	 *	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

	 *	(52 or 53) 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.

	 * 

	 * 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 + 1900);

			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;

}

#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

{

	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;

}