cringe-studios.com/visitor_counter.php

<?php

define("COUNTER_START_VALUE", 0);
define("COUNTER_LOG", "visit_counter.log"); //name of file you want to use to save the counter value

function getCounter() {
	if(!file_exists(COUNTER_LOG)) return str_pad(COUNTER_START_VALUE, 9, '0', STR_PAD_LEFT);

	if(!($fh = fopen(COUNTER_LOG, $create_file ? "x+b" : "r+b"))) return "Error";
	//do an flock here, maybe, I don't know :-)

	//Reading current value of counter:
	$count = (int)fread($fh, 9); //reads 9 digits (supposing max 1 billion count)

	if(!fclose($fh)) return "Error";

	return str_pad($count, 9, '0', STR_PAD_LEFT);
}

function incrementCounter() {
	$create_file = !file_exists(COUNTER_LOG);

	if(!($fh = fopen(COUNTER_LOG, $create_file ? "x+b" : "r+b"))) return "Error";
	//do an flock here, maybe, I don't know :-)

	//Reading current value of counter:
	if($create_file){
		$count = COUNTER_START_VALUE;
	}else{
		$count = (int)fread($fh, 9); //reads 9 digits (supposing max 1 billion count)
		rewind($fh);
	}

	//Writing new counter value:
	if(!fwrite($fh, ++$count)) return "Error";
	if(!fclose($fh)) return "Error";

	return "Success";
}

?>