BSD 3 development

[unix-history] / usr / src / libc / gen / timezone.c

/*
* The arguments are the number of minutes of time
* you are westward from Greenwich and whether DST is in effect.
* It returns a string
* giving the name of the local timezone.
*
* Sorry, I don't know all the names.
*/

static struct zone {
       int     offset;
       char    *stdzone;
       char    *dlzone;
} zonetab[] = {
       4*60, "AST", "ADT",             /* Atlantic */
       5*60, "EST", "EDT",             /* Eastern */
       6*60, "CST", "CDT",             /* Central */
       7*60, "MST", "MDT",             /* Mountain */
       8*60, "PST", "PDT",             /* Pacific */
       0, "GMT", 0,                    /* Greenwich */
       -1
};

char *timezone(zone, dst)
{
       register struct zone *zp;
       static char czone[10];
       char *sign;

       for (zp=zonetab; zp->offset!=-1; zp++)
               if (zp->offset==zone) {
                       if (dst && zp->dlzone)
                               return(zp->dlzone);
                       if (!dst && zp->stdzone)
                               return(zp->stdzone);
               }
       if (zone<0) {
               zone = -zone;
               sign = "+";
       } else
               sign = "-";
       sprintf(czone, "GMT%s%d:%02d", sign, zone/60, zone%60);
       return(czone);
}