/*
 * This OS/2 port was hacked by Harald Kipp from the
 *
 *      Network News Transfer Protocol server
 *
 *      Phil Lapsley
 *      University of California, Berkeley
 *      Stan Barber
 *      Baylor College of Medicine
 *
 * Bug reports related to THIS modified version should be sent to
 *
 *  harald@os2point.ping.de
 *  harald@haport.sesam.com
 *  Fido: 2:2448/434
 *
 */

/*
 * Collection of usefull routines for dealing with date and time.
 */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <time.h>

/*
 * dtol -- convert date to long integer.  This is not implicitly
 * local time, or any other kind of time, for that matter.  If you
 * pass it a date you think is GMT, you wind up with that number of
 * seconds...
 *
 *      Parameters:             "date_ascii" is in the form "yymmddhhmmss".
 *
 *      Returns:                Long integer containing number
 *                              of seconds since 000000 Jan 1, 1970,
 *                              and "date".  -1 on error.
 *
 *      Side effects:           None.
 */

#define twodigtoi(x)    (((x[0]) - '0') + (x[1] - '0')*10)
#define dysize(y)       ((y % 4 ? 365 : 366))

static int dmsize[12] =
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

long dtol(char *date_ascii)
{
    char date[32], *date_str;
    char *lhs, *rhs;
    char temp;
    long seconds;
    int year, month, day, hour, mins, secs;
    int len, i;

    len = strlen(date_ascii);
    if (len != sizeof("yymmddhhmmss") - 1)
	return (-1);

    strcpy(date, date_ascii);
    date_str = date;

    rhs = date_str + len - 1;
    lhs = date_str;

    for (; lhs < rhs; ++lhs, --rhs) {
	temp = *lhs;
	*lhs = *rhs;
	*rhs = temp;
	if (!isdigit(temp) || !isdigit(*lhs))
	    return (-1);
    }

    lhs = date_str;

    secs = twodigtoi(lhs);
    lhs += 2;
    mins = twodigtoi(lhs);
    lhs += 2;
    hour = twodigtoi(lhs);
    lhs += 2;
    day = twodigtoi(lhs);
    lhs += 2;
    month = twodigtoi(lhs);
    lhs += 2;
    year = twodigtoi(lhs);

    if (month < 1 || month > 12 ||
	    day < 1 || day > 31 ||
	    mins < 0 || mins > 59 ||
	    secs < 0 || secs > 59)
	return (-1);
    if (hour == 24) {
	hour = 0;
	day++;
    }
    if (hour < 0 || hour > 23)
	return (-1);
    seconds = 0;
    year += 1900;
    for (i = 1970; i < year; i++)
	seconds += dysize(i);
    /* Leap year */
    if (dysize(year) == 366 && month >= 3)
	seconds++;
    while (--month)
	seconds += dmsize[month - 1];
    seconds += day - 1;
    seconds = 24 * seconds + hour;
    seconds = 60 * seconds + mins;
    seconds = 60 * seconds + secs;

    return (seconds);
}


/*
 * ltod -- convert long integer to date string.
 *
 *      Parameters:             "date" is in the number of seconds
 *                              since the epoch.
 *
 *      Returns:                Pointer to static data in the form
 *                              yymmddhhmmss\0.
 *
 *      Side effects:           None.
 */

char *ltod(long date, char *timebuf)
{
    struct tm *tp;

    tp = gmtime(&date);

    sprintf(timebuf, "%02d%02d%02d%02d%02d%02d",
	    tp -> tm_year,
	    tp -> tm_mon + 1,
	    tp -> tm_mday,
	    tp -> tm_hour,
	    tp -> tm_min,
	    tp -> tm_sec);
    return (timebuf);
}

/*
 * local_to_gmt -- convert a local time (in form of number of
 * seconds since you-know-when) to GMT.
 *
 *      Parameters:     "date" is date we want converted, in
 *                      seconds since 000000 1 Jan 1970.
 *
 *      Returns:        Number of seconds corrected for local
 *                      and dst.
 */

long local_to_gmt(long date)
{

    tzset();
    date += timezone;
    if (daylight)
	date -= 60 * 60;
    return (date);
}

/*
 * gmt_to_local -- take a GMT time expressed in seconds since
 * the epoch, and convert it to local time.
 *
 *      Parameters:     "date" is the number of seconds...
 *
 *      Returns:        Number of seconds corrected to reflect
 *                      local time and dst.
 */

long gmt_to_local(long date)
{

    tzset();
    date -= timezone;
    if (daylight)
	date += 60 * 60;
    return (date);
}