/* Utility routines to manipulate and display universial format
   time and date information.
*/

#include <stdio.h>

/* Return time in clkbuf as formatted ascii string 23:59:59 */

char *fm24clk(clkbuf,clks)
	char *clkbuf,*clks;
{
	return(_fm24(clkbuf,clks,6));
}

/* Return time in clkbuf as formatted ascii string 23:59 */

char *fm244clk(clkbuf,clks)
	char *clkbuf,*clks;
{
	return(_fm24(clkbuf,clks,5));
}

/* Generalized time string decode/format.  */

char *_fm24(clkbuf,clks,ndigit)
	char *clkbuf,*clks;
	unsigned ndigit;
{
	char *p,*unpack();
	int i;
	
	p=clks;
	if((i = clkbuf[3]) > 127) {
		/* Relative clock detected */
		*p++ = '+';
		i &= 0x7f;
		i <<= 8;
		i += clkbuf[4];		/* turn into traditional int */
		_2dc(p,i,4,FALSE);		/* convert to 4 digits */
		if(ndigit==6)
			strcat(clks,"   ");	/* pad as needed to match rtc */
	} else {
		/* Real time clock */
		for(i=3;i<ndigit;i++) {	/* offset to time fields */
			p = unpack(clkbuf[i],p);
			*p++ = ':';
		}
		*(--p) = '\0';
	}
	return(clks);
}

/* Return date in clkbuf as a formatted string mm/dd/yy */

char *fmdate(clkbuf,dates)
	char *clkbuf,*dates;
{
	char *p, *unpack();
	
	p = dates;
	p = unpack(clkbuf[1],p);	/* month */
	*p++ = '/';
	p = unpack(clkbuf[2],p);	/* day */
	*p++ = '/';
	p = unpack(clkbuf[0],p);	/* year */
	*p = '\0';
	return(dates);
}

/* unpack bcd to 2 ascii chars in buff.  Return buff pointer pointing
   past low order ascii char.
*/

char *unpack(bcd,buff)
	int	bcd;
	char	*buff;
{
	*buff++ = ((bcd & 0x0f0) >> 4) + '0';
	*buff++ = (bcd & 0x0f) + '0';
	return(buff);
}