/* 

 * strftime.c --

 *

 *	This file contains a modified version of the BSD 4.4 strftime

 *	function.

 *

 * This file is a modified version of the strftime.c file from the BSD 4.4

 * source.  See the copyright notice below for details on redistribution

 * restrictions.  The "license.terms" file does not apply to this file.

 *

 * Changes 2002 Copyright (c) 2002 ActiveState Corporation.

 *

 * RCS: @(#) $Id: strftime.c,v 1.10.2.3 2005/11/04 18:18:04 kennykb Exp $

 */

/*

 * Copyright (c) 1989 The Regents of the University of California.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#if defined(LIBC_SCCS)

static char *rcsid = "$Id: strftime.c,v 1.10.2.3 2005/11/04 18:18:04 kennykb Exp $";

#endif /* LIBC_SCCS */

#include <time.h>

#include <string.h>

#include <locale.h>

#include "tclInt.h"

#include "tclPort.h"

#define TM_YEAR_BASE   1900

#define IsLeapYear(x)   ((x % 4 == 0) && (x % 100 != 0 || x % 400 == 0))

typedef struct {

    const char *abday[7];

    const char *day[7];

    const char *abmon[12];

    const char *mon[12];

    const char *am_pm[2];

    const char *d_t_fmt;

    const char *d_fmt;

    const char *t_fmt;

    const char *t_fmt_ampm;

} _TimeLocale;

/*

 * This is the C locale default.  On Windows, if we wanted to make this

 * localized, we would use GetLocaleInfo to get the correct values.

 * It may be acceptable to do localization of month/day names, as the

 * numerical values would be considered the locale-independent versions.

 */

static const _TimeLocale _DefaultTimeLocale = 

{

    {

	"Sun","Mon","Tue","Wed","Thu","Fri","Sat",

    },

    {

	"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",

	"Friday", "Saturday"

    },

    {

	"Jan", "Feb", "Mar", "Apr", "May", "Jun",

	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"

    },

    {

	"January", "February", "March", "April", "May", "June", "July",

	"August", "September", "October", "November", "December"

    },

    {

	"AM", "PM"

    },

    "%a %b %d %H:%M:%S %Y",

    "%m/%d/%y",

    "%H:%M:%S",

    "%I:%M:%S %p"

};

static const _TimeLocale *_CurrentTimeLocale = &_DefaultTimeLocale;

static int isGMT;

static size_t gsize;

static char *pt;

static int		 _add _ANSI_ARGS_((const char* str));

static int		_conv _ANSI_ARGS_((int n, int digits, int pad));

static int		_secs _ANSI_ARGS_((const struct tm *t));

static size_t		_fmt _ANSI_ARGS_((const char *format,

			    const struct tm *t));

static int ISO8601Week _ANSI_ARGS_((CONST struct tm* t, int *year ));

size_t

TclpStrftime(s, maxsize, format, t, useGMT)

    char *s;

    size_t maxsize;

    const char *format;

    const struct tm *t;

    int useGMT;

{

    if (format[0] == '%' && format[1] == 'Q') {

	/* Format as a stardate */

	sprintf(s, "Stardate %2d%03d.%01d",

		(((t->tm_year + TM_YEAR_BASE) + 377) - 2323),

		(((t->tm_yday + 1) * 1000) /

			(365 + IsLeapYear((t->tm_year + TM_YEAR_BASE)))),

		(((t->tm_hour * 60) + t->tm_min)/144));

	return(strlen(s));

    }

    isGMT = useGMT;

    /*

     * We may be able to skip this for useGMT, but it should be harmless.

     * -- hobbs

     */

    tzset();

    pt = s;

    if ((gsize = maxsize) < 1)

	return(0);

    if (_fmt(format, t)) {

	*pt = '\0';

	return(maxsize - gsize);

    }

    return(0);

}

#define SUN_WEEK(t)	(((t)->tm_yday + 7 - \

				((t)->tm_wday)) / 7)

#define MON_WEEK(t)	(((t)->tm_yday + 7 - \

				((t)->tm_wday ? (t)->tm_wday - 1 : 6)) / 7)

static size_t

_fmt(format, t)

    const char *format;

    const struct tm *t;

{

#ifdef WIN32

#define BUF_SIZ 256

    TCHAR buf[BUF_SIZ];

    SYSTEMTIME syst = {

	t->tm_year + 1900,

	t->tm_mon + 1,

	t->tm_wday,

	t->tm_mday,

	t->tm_hour,

	t->tm_min,

	t->tm_sec,

	0,

    };

#endif

    for (; *format; ++format) {

	if (*format == '%') {

	    ++format;

	    if (*format == 'E') {

				/* Alternate Era */

		++format;

	    } else if (*format == 'O') {

				/* Alternate numeric symbols */

		++format;

	    }

	    switch(*format) {

		case '\0':

		    --format;

		    break;

		case 'A':

		    if (t->tm_wday < 0 || t->tm_wday > 6)

			return(0);

		    if (!_add(_CurrentTimeLocale->day[t->tm_wday]))

			return(0);

		    continue;

		case 'a':

		    if (t->tm_wday < 0 || t->tm_wday > 6)

			return(0);

		    if (!_add(_CurrentTimeLocale->abday[t->tm_wday]))

			return(0);

		    continue;

		case 'B':

		    if (t->tm_mon < 0 || t->tm_mon > 11)

			return(0);

		    if (!_add(_CurrentTimeLocale->mon[t->tm_mon]))

			return(0);

		    continue;

		case 'b':

		case 'h':

		    if (t->tm_mon < 0 || t->tm_mon > 11)

			return(0);

		    if (!_add(_CurrentTimeLocale->abmon[t->tm_mon]))

			return(0);

		    continue;

		case 'C':

		    if (!_conv((t->tm_year + TM_YEAR_BASE) / 100,

			    2, '0'))

			return(0);

		    continue;

		case 'D':

		    if (!_fmt("%m/%d/%y", t))

			return(0);

		    continue;

		case 'd':

		    if (!_conv(t->tm_mday, 2, '0'))

			return(0);

		    continue;

		case 'e':

		    if (!_conv(t->tm_mday, 2, ' '))

			return(0);

		    continue;

	        case 'g':

		    {

			int year;

			ISO8601Week( t, &year );

			if ( !_conv( year%100, 2, '0' ) ) {

			    return( 0 );

			}

			continue;

		    }

	        case 'G':

		    {

			int year;

			ISO8601Week( t, &year );

			if ( !_conv( year, 4, '0' ) ) {

			    return( 0 );

			}

			continue;

		    }

		case 'H':

		    if (!_conv(t->tm_hour, 2, '0'))

			return(0);

		    continue;

		case 'I':

		    if (!_conv(t->tm_hour % 12 ?

			    t->tm_hour % 12 : 12, 2, '0'))

			return(0);

		    continue;

		case 'j':

		    if (!_conv(t->tm_yday + 1, 3, '0'))

			return(0);

		    continue;

		case 'k':

		    if (!_conv(t->tm_hour, 2, ' '))

			return(0);

		    continue;

		case 'l':

		    if (!_conv(t->tm_hour % 12 ?

			    t->tm_hour % 12: 12, 2, ' '))

			return(0);

		    continue;

		case 'M':

		    if (!_conv(t->tm_min, 2, '0'))

			return(0);

		    continue;

		case 'm':

		    if (!_conv(t->tm_mon + 1, 2, '0'))

			return(0);

		    continue;

		case 'n':

		    if (!_add("\n"))

			return(0);

		    continue;

		case 'p':

		    if (!_add(_CurrentTimeLocale->am_pm[t->tm_hour >= 12]))

			return(0);

		    continue;

		case 'R':

		    if (!_fmt("%H:%M", t))

			return(0);

		    continue;

		case 'r':

		    if (!_fmt(_CurrentTimeLocale->t_fmt_ampm, t))

			return(0);

		    continue;

		case 'S':

		    if (!_conv(t->tm_sec, 2, '0'))

			return(0);

		    continue;

		case 's':

		    if (!_secs(t))

			return(0);

		    continue;

		case 'T':

		    if (!_fmt("%H:%M:%S", t))

			return(0);

		    continue;

		case 't':

		    if (!_add("\t"))

			return(0);

		    continue;

		case 'U':

		    if (!_conv(SUN_WEEK(t), 2, '0'))

			return(0);

		    continue;

		case 'u':

		    if (!_conv(t->tm_wday ? t->tm_wday : 7, 1, '0'))

			return(0);

		    continue;

		case 'V':

		{

		    int week = ISO8601Week( t, NULL );

		    if (!_conv(week, 2, '0'))

			return(0);

		    continue;

		}

		case 'W':

		    if (!_conv(MON_WEEK(t), 2, '0'))

			return(0);

		    continue;

		case 'w':

		    if (!_conv(t->tm_wday, 1, '0'))

			return(0);

		    continue;

#ifdef WIN32

		/*

		 * To properly handle the localized time routines on Windows,

		 * we must make use of the special localized calls.

		 */

		case 'c':

		    if (!GetDateFormat(LOCALE_USER_DEFAULT,

				       DATE_LONGDATE | LOCALE_USE_CP_ACP,

				       &syst, NULL, buf, BUF_SIZ)

			|| !_add(buf)

			|| !_add(" ")) {

			return(0);

		    }

		    /*

		     * %c is created with LONGDATE + " " + TIME on Windows,

		     * so continue to %X case here.

		     */

		case 'X':

		    if (!GetTimeFormat(LOCALE_USER_DEFAULT,

				       LOCALE_USE_CP_ACP,

				       &syst, NULL, buf, BUF_SIZ)

			|| !_add(buf)) {

			return(0);

		    }

		    continue;

		case 'x':

		    if (!GetDateFormat(LOCALE_USER_DEFAULT,

				       DATE_SHORTDATE | LOCALE_USE_CP_ACP,

				       &syst, NULL, buf, BUF_SIZ)

			|| !_add(buf)) {

			return(0);

		    }

		    continue;

#else

		case 'c':

		    if (!_fmt(_CurrentTimeLocale->d_t_fmt, t))

			return(0);

		    continue;

		case 'x':

		    if (!_fmt(_CurrentTimeLocale->d_fmt, t))

			return(0);

		    continue;

		case 'X':

		    if (!_fmt(_CurrentTimeLocale->t_fmt, t))

			return(0);

		    continue;

#endif

		case 'y':

		    if (!_conv((t->tm_year + TM_YEAR_BASE) % 100,

			    2, '0'))

			return(0);

		    continue;

		case 'Y':

		    if (!_conv((t->tm_year + TM_YEAR_BASE), 4, '0'))

			return(0);

		    continue;

		case 'Z': {

		    char *name = (isGMT ? "GMT" : TclpGetTZName(t->tm_isdst));

		    int wrote;

		    Tcl_UtfToExternal(NULL, NULL, name, -1, 0, NULL,

				      pt, gsize, NULL, &wrote, NULL);

		    pt += wrote;

		    gsize -= wrote;

		    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) does.

		     */

		default:

		    break;

	    }

	}

	if (!gsize--)

	    return(0);

	*pt++ = *format;

    }

    return(gsize);

}

static int

_secs(t)

    const struct tm *t;

{

    static char buf[15];

    register time_t s;

    register char *p;

    struct tm tmp;

    /* Make a copy, mktime(3) modifies the tm struct. */

    tmp = *t;

    s = mktime(&tmp);

    for (p = buf + sizeof(buf) - 2; s > 0 && p > buf; s /= 10)

	*p-- = (char)(s % 10 + '0');

    return(_add(++p));

}

static int

_conv(n, digits, pad)

    int n, digits;

    int pad;

{

    static char buf[10];

    register char *p;

    p = buf + sizeof( buf ) - 1;

    *p-- = '\0';

    if ( n == 0 ) {

	*p-- = '0'; --digits;

    } else {

	for (; n > 0 && p > buf; n /= 10, --digits)

	    *p-- = (char)(n % 10 + '0');

    }

    while (p > buf && digits-- > 0)

	*p-- = (char) pad;

    return(_add(++p));

}

static int

_add(str)

    const char *str;

{

    for (;; ++pt, --gsize) {

	if (!gsize)

	    return(0);

	if (!(*pt = *str++))

	    return(1);

    }

}

static int

ISO8601Week( t, year )

    CONST struct tm* t;

    int* year;

{

    /* Find the day-of-year of the Thursday in

     * the week in question. */

    int ydayThursday;

    int week;

    if ( t->tm_wday == 0 ) {

	ydayThursday = t->tm_yday - 3;

    } else {

	ydayThursday = t->tm_yday - t->tm_wday + 4;

    }

    if ( ydayThursday < 0 ) {

	/* This is the last week of the previous year. */

	if ( IsLeapYear(( t->tm_year + TM_YEAR_BASE - 1 )) ) {

	    ydayThursday += 366;

	} else {

	    ydayThursday += 365;

	}

	week = ydayThursday / 7 + 1;

	if ( year != NULL ) {

	    *year = t->tm_year + 1899;

	}

    } else if ( ( IsLeapYear(( t -> tm_year + TM_YEAR_BASE ))

		  && ydayThursday >= 366 )

		|| ( !IsLeapYear(( t -> tm_year

				   + TM_YEAR_BASE ))

		     && ydayThursday >= 365 ) ) {

	/* This is week 1 of the following year */

	week = 1;

	if ( year != NULL ) {

	    *year = t->tm_year + 1901;

	}

    } else {

	week = ydayThursday / 7 + 1;

	if ( year != NULL ) {

	    *year = t->tm_year + 1900;

	}

    }

    return week;

}