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

/*	Compile this into a shared object:
	gcc -maix64 -shared -Wl,-b64,-brtl,-G datetots.c -o datetots.so
	cc -q64 -qmkshrobj -Wl,-b64,-brtl,-G datetots.c -o datetots.so
*/

/* Parameters:

	datetots( date, time )
		date = yyyymmdd
		time = hhmm

	Returns timestamp as a long

*/

long datetots( char *cdate, char *ctime )
{

	struct tm *dt;
	int curr_isdst;
	int date_isdst;

	time_t ts;

/*	What's the ISDST at the moment? */

	ts = time( NULL );
	dt = localtime( &ts );

	curr_isdst = dt->tm_isdst;

	long sdate = atol(cdate);
	long stime = atol(ctime);

/*	Set values in tm struct */

	dt->tm_year = (sdate / 10000) - 1900;
	sdate = sdate % 10000;

	dt->tm_mon = (sdate / 100) - 1;
	dt->tm_mday = sdate % 100;

	dt->tm_hour = stime / 10000;
	stime = stime % 10000;

	dt->tm_min = stime / 100;
	dt->tm_sec = stime % 100;

	ts = mktime(dt);

/*	Now compensate for whatever has happened to ISDST */

	date_isdst = dt->tm_isdst;

	ts = ts + ((date_isdst - curr_isdst) * 3600);

	return ( ts );

}