/*
 * Routine to convert a localtime(3) format date back into
 * a system format date.
 *
 * Hats off to Bob Kridle for the insight that the way to do
 * this is by binary search of the system date space.
 */

#include <sys/time.h>

struct tm *localtime();

long
emitl(dp)
	struct tm *dp;
{
	long conv;
	register int i, bit;
	struct tm dcopy;

	dcopy = *dp;
	dp = &dcopy;
	conv = 0;
	for (i = 31; i >= 0; i--) {
		bit = 1 << i;
		conv |= bit;
		if (dcmp(localtime(&conv), dp) > 0)
			conv &= ~bit;
	}
	return(conv);
}

/*
 * Compare two localtime dates, return result.
 */

#define DECIDE(a) \
	if (dp->a > dp2->a) \
		return(1); \
	if (dp->a < dp2->a) \
		return(-1)

static
dcmp(dp, dp2)
	register struct tm *dp, *dp2;
{

	DECIDE(tm_year);
	DECIDE(tm_mon);
	DECIDE(tm_mday);
	DECIDE(tm_hour);
	DECIDE(tm_min);
	DECIDE(tm_sec);
	return(0);
}