#!/usr/bin/perl

require './gifcat.pl';

$base = './cntdata';					#データ格納ディレクトリ
$totalfile = "$base/total.txt";			#カウンタ
$lastfile = "$base/last.txt";
$lockfile = "$base/lock";

###　メイン処理　###
&lock;
$addr = $ENV{'REMOTE_ADDR'};
open (IN,"$lastfile") || &error("OPEN ERROR");		$paddr = <IN>;		close IN;
if ($addr ne $paddr) {
	open (OUT,">$lastfile") || &error("OPEN ERROR");	print OUT $addr;	close OUT;
	open (IN,"$totalfile") || &error("OPEN ERROR");		$total = <IN>;		close IN;
	$total++;
	open (OUT,">$totalfile") || &error("OPEN ERROR");	print OUT $total;	close OUT;
}
&unlock;

open (IN,"$totalfile") || &error("OPEN ERROR");		$total = <IN>;		close IN;
$size = length($total);
if ($size < 4) {$total = sprintf("%04d",$total); $size = 4;}

print "Content-type: image/gif\n\n";
@img = ();
for (0 .. $size-1) {
	$n = substr($total,$_,1);
	$n = "$base/$n.gif";
	push (@img,$n);
}
binmode(STDOUT);
print &gifcat'gifcat(@img);
exit;

###
sub lock {
	$retry = 3;
	if (-e $lockfile) {
		$locktime = (stat($lockfile))[9];
		if ($locktime < time - 60) {&unlock;}
	}
	while (!mkdir($lockfile, 0755)) {
		if (--$retry < 0) {&error("busy!");}
		sleep(1);
	}
}

###
sub unlock {rmdir($lockfile);}

###
sub error {exit;}