use Time::Local ;
use Math::BigInt ;

sub SysToHex {

	my ($sec,$min,$hour,$mday,$mon,$year)= @_ ;
	my $sectime = timegm($sec,$min,$hour,$mday,$mon,$year) ;
	
	my @hexReg1601  ;  # Result
	
	# Conversion to intervals of 100 nanosecondes since 1970 
	my $secsystime = Math::BigInt -> new( $sectime )  ;
	my $nano100= Math::BigInt -> new(10000000)  ;
	my$nanosecsys = $secsystime -> bmul ( $nano100 ) ;
	
	# 100 ns intervals since 1601 and 1970
	# obtained within windows by manualy
	# entering the date 01/01/1970
	my $hex1970 = '0x019DB1DED53E8000' ;
	my $nano1970 = X2I ( $hex1970 ) ;
	
	# Total number of 100ns intervals
	my $sec1601 = $nano1970 + $nanosecsys ; 
	my $hex1601 = I2X ( $sec1601) ;
	
	# This coma separated format is expected by the registry
	my @liste1601 = split ( "", $hex1601 ) ;
	unshift (@liste1601, "0" ) unless ( @liste1601 % 2 == 0 )  ;
	while (@liste1601)  { 
	push ( @hexReg1601, splice (  @liste1601, -2 ), "," ) 
	}
	pop @hexReg1601 ; # Gets rid of the last coma
	
	return join ( "", @hexReg1601 ) ;

} 

sub X2I {
	my $n = shift;
	$n = '0' x (4 - (length($n) % 4)) . $n;
	my $m = Math::BigInt->new(0);
	while ( my $o = substr($n, 0, 4, '') ) {
		$m = $m * 65536 + hex $o;
	} 
	$m;
}


sub I2X {
	my $i = shift;
	my $hex = '';
		do {
		my $mod = $i % 16;
		$hex .= sprintf("%x", $mod);
		} while $i = $i / 16;
        scalar reverse $hex;
}