php自持小型分页代码

<?php ini_set('memory_limit','-1');if(!$_GET['page'])$line=1;//fy//else $line=$_GET['page'];$f=file("a.pdf");if(count($f)>500){	for($i=($line-1)*500;$i<$line*500;$i++) 	{		echo $f[$i]."<br>";# code...	}}else {	foreach ($f as $key) 	{		echo $key."<br>";# code...	}}?><meta charset="utf-8"><title>xiaoshuo</title><link rel="stylesheet" href="./assets/css/amazeui.min.css"><div class="am-g">  <div class=" col-md-8 col-sm-centered">    <form class="am-form" action="#" method="get">      <fieldset class="am-form-set">        <input type="text" id="page" name="page" placeholder="页数">      </fieldset>      <div><button type="submit" class="am-btn am-btn-primary am-btn-block">走你</button></div>    </form>  </div></div>