php生成微博短网址的算法

php代码

<?php
function code62($x) {
	$show = '';
	while($x > 0) {
		$s = $x % 62;
		if ($s > 35) {
			$s = chr($s+61);
		} elseif ($s > 9 && $s <=35) {
			$s = chr($s + 55);
		}
		$show .= $s;
		$x = floor($x/62);
	}
	return $show;
}
  
function shorturl($url) {
	$url = crc32($url);
	$result = sprintf("%u", $url);
	//return $url;
	//return $result;
	return code62($result);
}

echo shorturl("此处为网址");
?>