PHP，获取配置文件中，允许上传文件最大尺寸

<?php

// this function was be got from phpmyadmin
function PMA_get_real_size($size = 0)
{
    if (! $size) {
        return 0;
    }

    $scan['gb'] = 1073741824; //1024 * 1024 * 1024;
    $scan['g']  = 1073741824; //1024 * 1024 * 1024;
    $scan['mb'] = 1048576;
    $scan['m']  = 1048576;
    $scan['kb'] =    1024;
    $scan['k']  =    1024;
    $scan['b']  =       1;

    foreach ($scan as $unit => $factor) {
        if (strlen($size) > strlen($unit)
         && strtolower(substr($size, strlen($size) - strlen($unit))) == $unit) {
            return substr($size, 0, strlen($size) - strlen($unit)) * $factor;
        }
    }

    return $size;
} // end function PMA_get_real_size()

$upload_max_filesize = PMA_get_real_size(ini_get('upload_max_filesize'));
$post_max_size = PMA_get_real_size(ini_get('post_max_size'));
$min_upload_size = $upload_max_filesize > $post_max_size ? $post_max_size : $upload_max_filesize;

echo  number_format($min_upload_size/1024).' KiB';
?>