Subversion Repositories planix.SVN

#include        "all.h"

static  int     sunday(Tm *t, int d);
static  int     dysize(int);
static  void    ct_numb(char*, int);
static  void    klocaltime(long tim, Tm *ct);
static  void    kgmtime(long tim, Tm *ct);

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

/*
 * The following table is used for 1974 and 1975 and
 * gives the day number of the first day after the Sunday of the
 * change.
 */
static  struct
{
        short   yrfrom;
        short   yrto;
        short   daylb;
        short   dayle;
} daytab[] =
{
        87,     999,    97,     303,
        76,     86,     119,    303,
        75,     75,     58,     303,
        74,     74,     5,      333,
        0,      73,     119,    303,
};

static struct
{
        short   minuteswest;    /* minutes west of Greenwich */
        short   dsttime;        /* dst correction */
} timezone =
{
        5*60, 1
};

static void
klocaltime(long tim, Tm *ct)
{
        int daylbegin, daylend, dayno, i;
        long copyt;

        copyt = tim - timezone.minuteswest*60L;
        kgmtime(copyt, ct);
        dayno = ct->yday;
        for(i=0;; i++)
                if(ct->year >= daytab[i].yrfrom &&
                   ct->year <= daytab[i].yrto) {
                        daylbegin = sunday(ct, daytab[i].daylb);
                        daylend = sunday(ct, daytab[i].dayle);
                        break;
                }
        if(timezone.dsttime &&
            (dayno>daylbegin || (dayno==daylbegin && ct->hour>=2)) &&
            (dayno<daylend || (dayno==daylend && ct->hour<1))) {
                copyt += 60L*60L;
                kgmtime(copyt, ct);
        }
}

/*
 * The argument is a 0-origin day number.
 * The value is the day number of the last
 * Sunday before or after the day.
 */
static
sunday(Tm *t, int d)
{
        if(d >= 58)
                d += dysize(t->year) - 365;
        return d - (d - t->yday + t->wday + 700) % 7;
}

static void
kgmtime(long tim, Tm *ct)
{
        int d0, d1;
        long hms, day;

        /*
         * break initial number into days
         */
        hms = tim % 86400L;
        day = tim / 86400L;
        if(hms < 0) {
                hms += 86400L;
                day -= 1;
        }

        /*
         * generate hours:minutes:seconds
         */
        ct->sec = hms % 60;
        d1 = hms / 60;
        ct->min = d1 % 60;
        d1 /= 60;
        ct->hour = d1;

        /*
         * day is the day number.
         * generate day of the week.
         * The addend is 4 mod 7 (1/1/1970 was Thursday)
         */

        ct->wday = (day + 7340036L) % 7;

        /*
         * year number
         */
        if(day >= 0)
                for(d1 = 70; day >= dysize(d1); d1++)
                        day -= dysize(d1);
        else
                for (d1 = 70; day < 0; d1--)
                        day += dysize(d1-1);
        ct->year = d1;
        ct->yday = d0 = day;

        /*
         * generate month
         */

        if(dysize(d1) == 366)
                dmsize[1] = 29;
        for(d1 = 0; d0 >= dmsize[d1]; d1++)
                d0 -= dmsize[d1];
        dmsize[1] = 28;
        ct->mday = d0 + 1;
        ct->mon = d1;
}

void
datestr(char *s, long t)
{
        Tm tm;

        klocaltime(t, &tm);
        sprint(s, "%.4d%.2d%.2d", tm.year+1900, tm.mon+1, tm.mday);
}

int
Tfmt(Fmt *f1)
{
        char s[30];
        char *cp;
        long t;
        Tm tm;

        t = va_arg(f1->args, long);
        if(t == 0)
                return fmtstrcpy(f1, "The Epoch");

        klocaltime(t, &tm);
        strcpy(s, "Day Mon 00 00:00:00 1900");
        cp = &"SunMonTueWedThuFriSat"[tm.wday*3];
        s[0] = cp[0];
        s[1] = cp[1];
        s[2] = cp[2];
        cp = &"JanFebMarAprMayJunJulAugSepOctNovDec"[tm.mon*3];
        s[4] = cp[0];
        s[5] = cp[1];
        s[6] = cp[2];
        ct_numb(s+8, tm.mday);
        ct_numb(s+11, tm.hour+100);
        ct_numb(s+14, tm.min+100);
        ct_numb(s+17, tm.sec+100);
        if(tm.year >= 100) {
                s[20] = '2';
                s[21] = '0';
        }
        ct_numb(s+22, tm.year+100);

        return fmtstrcpy(f1, s);
}

static
dysize(int y)
{

        if((y%4) == 0)
                return 366;
        return 365;
}

static
void
ct_numb(char *cp, int n)
{

        if(n >= 10)
                cp[0] = (n/10)%10 + '0';
        else
                cp[0] = ' ';
        cp[1] = n%10 + '0';
}

/*
 * compute the next time after t
 * that has hour hr and is not on
 * day in bitpattern --
 * for automatic dumps
 */
long
nextime(long t, int hr, int day)
{
        Tm tm;
        int nhr;

        if(hr < 0 || hr >= 24)
                hr = 5;
        if((day&0x7f) == 0x7f)
                day = 0;

loop:
        klocaltime(t, &tm);
        t -= tm.sec;
        t -= tm.min*60;
        nhr = tm.hour;
        do {
                t += 60*60;
                nhr++;
        } while(nhr%24 != hr);
        klocaltime(t, &tm);
        if(tm.hour != hr) {
                t += 60*60;
                klocaltime(t, &tm);
                if(tm.hour != hr) {
                        t -= 60*60;
                        klocaltime(t, &tm);
                }
        }
        if(day & (1<<tm.wday)) {
                t += 12*60*60;
                goto loop;
        }
        return t;
}