Memory-friendly function that compares two files and returns a boolean

filecomp.php

<?php
if(compare_files('file1', 'file2'))
	echo 'Files are similar', PHP_EOL;
else
	echo 'Files are different', PHP_EOL;

function compare_files($a, $b, $buf_size = 1048576)
{
	if($a === $b)
		return true;
	if(filesize($a) != filesize($b))
		return false;
	$fa = fopen($a, 'rb');
	$fb = fopen($b, 'rb');
	while(!feof($fa))
	{
		$buf = fread($fa, $buf_size);
		if($buf != fread($fb, $buf_size))
			return false;
	}
	fclose($fa);
	fclose($fb);
	return true;
}