/*
 * compat.c -- functions that we need to provide because they are missing 
 */

/*
 * $Id: compat.c,v 1.2 2005/08/08 09:43:05 murrayma Exp $ 
 */

#include "copyright.h"
#include "config.h"

#ifdef NEED_TIMELOCAL

#define	altzone		((time_t)(timezone + 3600))

/*
 * CAUTION: side effects 
 */
#define	is_leap(x)	(((!((x)%4)&&(x)%100)||!(((x)+1900)%400))?1:0)

static int yday_size[2][12] = {
    {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
    {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
};

static int mon_size[2][12] = {
    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};

/*
 * e.g: normalize(&tm_secs, &tm_hour, 60); 
 */
static void normalize(x, y, f)
int *x, *y, f;
{
    if (*x >= f) {
	*y += *x / f;
	*x %= f;
    }
    /*
     * can't rely on modulus for negative numbers 
     */

    while (*x < 0) {
	*x += f;
	(*y)--;
    }
}

time_t timelocal(tp)
struct tm *tp;
{
    long unsigned k;
    struct tm tm;
    time_t t, t1;

    tzset();			/*
				 * set up time zone 
				 */

    /*
     * normalize the time 
     */
    normalize(&tp->tm_sec, &tp->tm_min, 60);
    normalize(&tp->tm_min, &tp->tm_hour, 60);
    normalize(&tp->tm_hour, &tp->tm_mday, 24);

    /*
     * normalize the month first 
     */
    normalize(&tp->tm_mon, &tp->tm_year, 12);

    /*
     * days to months a little tricky 
     */
    while (tp->tm_mday < 1) {
	if (--tp->tm_mon < 0) {
	    tp->tm_year--;
	    tp->tm_mon += 12;
	}
	tp->tm_mday += mon_size[is_leap(tp->tm_year)][tp->tm_mon];
    }

    while (tp->tm_mday > (k = mon_size[is_leap(tp->tm_year)][tp->tm_mon])) {
	tp->tm_mday -= k;

	if (++tp->tm_mon > 12) {
	    tp->tm_year++;
	    tp->tm_mon -= 12;
	}
    }

    k = tp->tm_year / 4;	/*
				 * number of 4 year groups 
				 */
    t = (k * 1461) - 1;		/*
				 * number of days 
				 */
    k = tp->tm_year % 4;	/*
				 * number of years beyond group 
				 */
    t += (k * 365);		/*
				 * add number of days 
				 */
    if (k)			/*
				   * * if not group break year  
				 */
	t++;			/*
				 * add one day 
				 */

    /*
     * Since the epoch starts at Jan 1/70, we have to subtract the * of * 
     * 
     * *  * *  * *  * * days from Jan 1/00.  This is actually 25567 days. 
     * See  * * * below * for  *  * * the explanation of the discrepancy 
     */

    t -= 25568;			/*
				 * t = # days to 00:00:00 Jan 1/70 
				 */
    t += yday_size[is_leap(tp->tm_year)][tp->tm_mon];

    /*
     * Add the number of days in month.  Note that we should really * * * 
     * 
     * *  * *  * * subtract 1 from the day first but we effectively did
     * this * * * above * * * when we subtracted an extra day (25568
     * instead of * * 25567) 
     */

    t += tp->tm_mday;		/*
				 * # days to given day at 00:00:00 
				 */

    /*
     * now add in the number of seconds in the day 
     */

    t = (t * 24) + tp->tm_hour;
    t = (t * 60) + tp->tm_min;
    t = (t * 60) + tp->tm_sec;	/*
				 * total number of seconds 
				 */

    /*
     * if caller thinks he/she knows what time zone then believe them 
     */

    if (tp->tm_isdst == 0)
	t += timezone;
    else if (tp->tm_isdst > 0)
	t += altzone;
    else {
	/*
	 * we have to figure it out, guess dst first 
	 */

	t1 = t + altzone;
	tm = *localtime(&t1);

	/*
	 * see if the guess matches the reality 
	 */

	if (tm.tm_hour == tp->tm_hour && tm.tm_min == tp->tm_min)
	    t = t1;
	else {

#ifdef CHECK_INVALID

	    /*
	     * if CHECK_INVALID is defined then we attempt to * * 
	     * 
	     * *  * *  * *  * * check for the invalid time case
	     * e.g. a  * time  * of *  * *  * 0230h on the first
	     * sunday in * April * will * return -1 * * * -
	     * personally I * don't think * this is  * polite * * 
	     * behaviour 
	     */

	    t1 = t + timezone;
	    tm = *localtime(&t1);

	    if ((tm.tm_hour == tp->tm_hour) && (tm.tm_min == tp->tm_min))
		t = t1;
	    else
		return (-1);
#else
	    t += timezone;
#endif
	}
    }

    *tp = *localtime(&t);	/*
				 * set other fields in structure 
				 */
    return (t);
}

#endif				/*
				 * * NEED_TIMELOCAL  
				 */

/*
 * Need strnlen
 */

#ifndef HAVE_STRNLEN
size_t strnlen(const char *s, size_t maxlen) { 

    int count; 
    
    for(count = 0; count < maxlen && s[count] != '\x0'; count++); 
    
    return count; 

}
#endif

/*
 * Need strndup
 */
#ifndef HAVE_STRNDUP
char *strndup(const char *s, size_t n) {

    int length; 
    char *buf;
    
    length = strnlen(s, n); 
    buf = malloc(length + 1);
    memset(buf, '\0', length + 1);
    strncpy(buf, s, length); 
 
    return buf; 

}
#endif