WebAdverts (CGI Display)

############################################
##                                        ##
##        WebAdverts (CGI Display)        ##
##           by Darryl Burgdorf           ##
##       (e-mail burgdorf@awsd.com)       ##
##                                        ##
##         last modified: 5/27/97         ##
##           copyright (c) 1997           ##
##                                        ##
##    latest version is available from    ##
##        http://awsd.com/scripts/        ##
##                                        ##
############################################

sub insertadvert {
	require "/usr/www/users/dburgdor/scripts/ads/ads_configure.pl";
	&ConfigureAdverts;
	$ADVUseLocking = 1;
	$ADVWrapCounter = 0;
	&ADVdisplayad;
	srand();
}

sub ADVdisplayad {
	$ADVWrapCounter++;
	open (ADVCOUNT, "+<$advertcount");
	$ADVlockerror = &ADVLockFile(ADVCOUNT);
	if ($ADVlockerror) {
		print "[ File Lock Error ($advertcount)! ]";
		return;
	}
	@ADVlines = <ADVCOUNT>;
	if ((@ADVlines < 4) || ($ADVWrapCounter > @ADVlines-3)) {
		&ADVUnlockFile(ADVCOUNT);
		close (ADVCOUNT);
		return;
	}
	foreach $ADVline (@ADVlines) { chop ($ADVline) if ($ADVline =~ /\n$/); }
	$ADVcount = $ADVlines[0];
	$ADVexposures = $ADVlines[1];
	$ADVdisplayad = $ADVlines[$ADVcount+2];
	$ADVexposures++;
	$ADVcount++;
	if ($ADVcount > @ADVlines-3) { $ADVcount = 1; }
	$ADVlines[0] = $ADVcount;
	unless ($ADVshown > 0) {
		$ADVlines[1] = $ADVexposures;
	}
	truncate (ADVCOUNT,0);
	seek(ADVCOUNT, 0, 0);
	foreach $ADVline (@ADVlines) { print ADVCOUNT "$ADVline\n"; }
	&ADVUnlockFile(ADVCOUNT);
	close (ADVCOUNT);
	open (ADVDISPLAY, "+<$adverts_dir/$ADVdisplayad.txt");
	$ADVlockerror = &ADVLockFile(ADVDISPLAY);
	if ($ADVlockerror) {
		print "[ File Lock Error ($ADVdisplayad.txt)! ]";
		return;
	}
	@ADVlines = <ADVDISPLAY>;
	foreach $ADVline (@ADVlines) { chop ($ADVline) if ($ADVline =~ /\n$/); }
	($ADVmax,$ADVshown,$ADVvisits,$ADVurl,$ADVimage,$ADVheight,$ADVwidth,$ADValt,$ADVpass,$ADVtext,$ADVstart,$ADVweight) = @ADVlines;
	unless ($ADVweight) { $ADVweight = 1; }
	unless ($ADVtext) { $ADVtext = "Please Visit Our Sponsor!"; }
	if ((($AdvertTracking < 2) && ($ADVmax <= $ADVshown)) ||
	  (($AdvertTracking == 2) && ($ADVmax <= $ADVvisits)) ||
	  ((rand) > $ADVweight)) {
		&ADVUnlockFile(ADVDISPLAY);
		close (ADVDISPLAY);
		&ADVdisplayad;
		return;
	}
	print "<P ALIGN=CENTER><A HREF=\"$gotoadvert?$ADVdisplayad\">";
	print "<IMG SRC=\"$ADVimage\" HEIGHT=$ADVheight WIDTH=$ADVwidth ALT=\"$ADValt\">";
	print "</A><BR><SMALL><A HREF=\"$gotoadvert?$ADVdisplayad\">";
	print "$ADVtext</A></SMALL></P>\n";
	$ADVshown += 1;
	truncate (ADVDISPLAY,0);
	seek(ADVDISPLAY, 0, 0);
	print ADVDISPLAY "$ADVmax\n";
	print ADVDISPLAY "$ADVshown\n";
	print ADVDISPLAY "$ADVvisits\n";
	print ADVDISPLAY "$ADVurl\n";
	print ADVDISPLAY "$ADVimage\n";
	print ADVDISPLAY "$ADVheight\n";
	print ADVDISPLAY "$ADVwidth\n";
	print ADVDISPLAY "$ADValt\n";
	print ADVDISPLAY "$ADVpass\n";
	print ADVDISPLAY "$ADVtext\n";
	print ADVDISPLAY "$ADVstart\n";
	print ADVDISPLAY "$ADVweight\n";
	&ADVUnlockFile(ADVDISPLAY);
	close (ADVDISPLAY);
	return;
}

sub ADVLockFile {
	local(*FILE) = @_;
	local($ADVTrysLeft) = 10;
	if ($ADVUseLocking) {
		while ($ADVTrysLeft--) {
			$ADVlockresult = eval("flock(FILE,6)");
			if ($@) {
				$ADVUseLocking = 0;
				last;
			}
			if (!$ADVlockresult) {
				select(undef,undef,undef,0.1);
			}
			else {
				last;
			}
		}
	}
	if ($ADVTrysLeft >= 0) {
		return 0;
	}
	else {
		return -1;
	}
}

sub ADVUnlockFile {
	local(*FILE) = @_;
	if ($ADVUseLocking) {
		flock(FILE,8);
	}
}

1;