#!/usr/local/bin/perl

# Simple SSI counter v1.2 (Jan-06-2000)
# Copyright (C) 1999-2000 Kan-chan <kan-chan@innocent.com>
#  Web site: http://kan-chan.stbbs.net/download/
#
# This program is free software; you can redistribute it and/or 
# modify it under the terms of the GNU General Public License as 
# published by the Free Software Foundation; either version 2 of 
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, 
# but WITHOUT ANY WARRANTY; without even the implied warranty of 
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public 
# License along with this program; if not, write to the Free 
# Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

# Release note:
# v1.2 (Jan-06-2000)
#   Small bug fixes.
# v1.1 (Nov-24-1999)
#   Added PNG support.
# v1.0 (Jan-07-1999)
#   First release.

# Usage:
# 1. Modify the perl directory written on the top of this script 
#    if it is required.
# 2. Modify the value of $basedir/$imagedir/$countfile/$lockfile if 
#    the directory and/or file name are different.
# 3. Upload files to the following directories and change the 
#    permission.  If you cannot use 707/705/606, try 777/755/666.
# 4. Add <!--#exec cmd="./count/count.pl"--> to index.html
#
# public_html/
#      |
#      |-- index.html
#      |-- .htaccess  (most systems require this to run SSI scripts)
#      |
#      |-- images/
#      |      |-- 0.gif
#      |      |-- 1.gif
#      |      |     :
#      |      |     :
#      |      |-- 8.gif
#      |      |-- 9.gif
#      |
#      |-- count/           (permission:707 or 777)
#             |-- count.pl  (permission:705 or 755)
#             |-- count.txt (permission:606 or 666)
#

# Where you installed count.pl/count.txt (location from index.html)
$basedir = "./count/";
# Where you installed 0.gif~9.gif (location from index.html)
$imagedir = "./images/";
# The extension of the digit file (.gif / .jpg / .png  etc.)
$ext = ".gif";
# The name of count file
$countfile = "count.txt";
# The name of temporary file to lock the process
$lockfile = "count.loc";

$countfilepath = $basedir.$countfile;
$lockfilepath = $basedir.$lockfile;

# Error messages
$err_busy = "[Server busy!]";
$err_open = "[Cannot open count file! ($countfilepath)]";

# Wait until the lock is released
for ($i=1;$i<=6;$i++){
	if (!(-e $lockfilepath)) {
		last;
	} elsif ($i == 1){
		$filetime = (stat($lockfilepath))[9];
		if ($filetime < time() - 10 * 60){
			&unlock();
		}
	} elsif ($i >= 6){
		&error($err_busy);
	}
	sleep(1);
}

# Create a lock file
open(OUT, ">$lockfilepath");
close(OUT);

# Read/write count file
if (!open(IN, "<$countfilepath")) {
	&unlock();
	&error($err_open);
}
$count = <IN>;
close(IN);
$count++;
if (!open(OUT, ">$countfilepath")) {
	&unlock();
	&error($err_open);
}
print(OUT $count);
close(OUT);

# Output a number as HTML tags
&disp($count);

# Remove the lock file
&unlock();

# Exit this program
exit;

# If a lock file exists, delete the file
sub unlock {
	if (-e $lockfilepath) { unlink($lockfilepath); }
}

# Output a number as HTML tags
sub disp {
	$count = $_[0];
	foreach (0..length($count)-1) {
		$n = substr($count, $_, 1);
		print "<img src=\"$imagedir$n$ext\" alt=\"$n\" border=0>";
	}
}

# Output an error mesasge
sub error {
	print "$_[0]";
	exit;
}