如何通过php文件系统函数获取磁盘分区的大小

float disk_total_space(string directory)

float disk_free_space(string directory)

<form name="form1" action="6.php" method="post">
   文件名称： <input name="file_name" type="text">
           <input type="submit" name="Submit" value="提交">
</form>
<?php
header("Content-Type:text/html; charset=utf-8");
if ($_POST['file_name']){
if($_POST['file_name']!="" && is_file($_POST['file_name'])==false){
    $file_name = iconv("utf-8","gb2312",$_POST['file_name']);      // 编码格式转换
    if (file_exists($file_name)){                                  //判断目录是否存在
        $len = strripos($file_name,":");                            //截取字符串
        $dir = substr($file_name,0,$len+1);                        //获取提交目录所在磁盘
        $filesize_z = disk_total_space($dir);                       //获取目录大小
        $filesize_z = number_format($filesize_z/(1024*1024*1024),2,".","");    //数字的格式化
        $filesize_s = disk_free_space($dir);                            //获取裁判剩余空间
        $filesize_s =  number_format($filesize_s/(1024*1024*1024),2,".",""); //字节的格式化
        echo "本地磁盘（".$dir."） 总大小：".$filesize_z." GB   可用空间：".$filesize_s."GB <br><br>";
        echo $_POST['file_name']."目录下的内容："."<br>";
        $i = 0;
        $list = opendir($file_name);                                //打开目录
        while($read_list = readdir($list)){                         //读取目录
            $i++;
            echo "$i:".iconv("gb2312","utf-8",$read_list)."<br>";   //输出目录中的内容
        }
        closedir($list);                                            //关于目录
    }else{
        echo "<script>alert('目录不存在！');</script>";
    }
}else{
    echo "<script>alert('请输入正确的目录路径！');</script>";
}
}

$len = strripos($file_name,":");                            //截取字符串
$dir = substr($file_name,0,$len+1);                        //获取提交目录所在磁盘