PHP code for detecting image Trojans (multiple programming)

<?php 
/** 
* Upload 文件上传类
* 用于检测木马文件
*/ 
class Upload { 
private static $image = null; 
private static $status = 0; 
private static $suffix = null; 
private static $imageType = array('.jpg', '.bmp','.gif','.png'); 
private static $message = array( 
'0' => '没有错误发生，文件上传成功。', 
'1' => '上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值。', 
'2' => '上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值。', 
'3' => '文件只有部分被上传。', 
'4' => '没有文件上传。', 
'5' => '未能通过安全检查的文件。', 
'6' => '找不到临时文件夹。', 
'7' => '文件写入失败。', 
'8' => '文件类型不支持', 
'9' => '上传的临时文件丢失。', 
); 
//@ 开始执行文件上传 
public static function start($feild = 'file') { 
if (!empty($_FILES)) { 
self::$status = $_FILES[$feild]['error']; 
if (self::$status > 0) 
return array('status' => self::$status, 'msg' => self::$message[self::$status]); 
self::$image = $_FILES[$feild]['tmp_name']; 
self::$suffix = strtolower(strrchr($_FILES[$feild]['name'], '.')); 
return array('status' => self::_upload(), 'path' => self::$image, 'msg' => self::$message[self::$status]); 
} else { 
return array('status' => self::$status, 'msg' => self::$message[self::$status]); 
} 
} 
//@ 私有 上传开始 
private static function _upload($path = './upload/') { 
date_default_timezone_set('PRC'); 
$newFile = $path . date('Y/m/d/His') . rand(100, 999) . self::$suffix; 
self::umkdir(dirname($newFile)); 
if (is_uploaded_file(self::$image) && move_uploaded_file(self::$image, $newFile)) { 
self::$image = $newFile; 
if (in_array(self::$suffix, self::$imageType)) 
return self::checkHex(); 
else 
return self::$status = 0; 
} else { 
return self::$status = 9; 
} 
} 
//@ 私有 16进制检测 
private static function checkHex() { 
if (file_exists(self::$image)) { 
$resource = fopen(self::$image, 'rb'); 
$fileSize = filesize(self::$image); 
fseek($resource, 0); 
if ($fileSize > 512) { // 取头和尾 
$hexCode = bin2hex(fread($resource, 512)); 
fseek($resource, $fileSize - 512); 
$hexCode .= bin2hex(fread($resource, 512)); 
} else { // 取全部 
$hexCode = bin2hex(fread($resource, $fileSize)); 
} 
fclose($resource); 
/* 匹配16进制中的 <% ( ) %> */ 
/* 匹配16进制中的 <? ( ) ?> */ 
/* 匹配16进制中的 <script | /script> 大小写亦可*/ 
if (preg_match("/(3c25.*?28.*?29.*?253e)|(3c3f.*?28.*?29.*?3f3e)|(3C534352495054)|(2F5343524950543E)|(3C736372697074)|
(2F7363726970743E)/is", $hexCode)) 
self::$status = 5; 
else 
self::$status = 0; 
return self::$status; 
} else { 
return self::$status = 9; 
} 
} 
//@ 私有 创建目录 
private static function umkdir($dir) { 
if (!file_exists($dir) && !is_dir($dir)) { 
self::umkdir(dirname($dir)); 
@mkdir($dir); 
} 
} 
}