php查看运行时间、内存消耗

<?php
/*计算运行时间*/
class Runtime
{
var $StartTime = 0;
var $StopTime = 0;

function get_microtime()
{
list($usec, $sec) = explode(' ', microtime());
return ((float)$usec + (float)$sec);
}

function start()
{
$this->StartTime = $this->get_microtime();
}

function stop()
{
$this->StopTime = $this->get_microtime();
}

function spent()
{
return round(($this->StopTime - $this->StartTime) * 1000, 1);
}

/*格式化当前内存消耗*/
function memory(){
$size = memory_get_usage();
$unit = array('b','kb','mb','gb','tb','pb');
return @round($size/pow(1024,($i=floor(log($size,1024)))),2).' '.$unit[$i];
}
}
?>