/**

* 通过文件名，获得文件类型*

* @version 0.1

* $filename="d:/1.png";echo cFileTypeCheck::getFileType($filename); 打印：png

*/

class cFileTypeCheck

{

private static $_TypeList=array();

private static $CheckClass=null;

private function __construct($filename)

{

self::$_TypeList=$this->getTypeList();

}

/**

* 处理文件类型映射关系表*

*

* @param string $filename 文件类型

* @return string 文件类型，没有找到返回：other

*/

private function _getFileType($filename)

{

$filetype="other";

if(!file_exists($filename)) throw new Exception("no found file!");

$file = @fopen($filename,"rb");

if(!$file) throw new Exception("file refuse!");

$bin = fread($file, 15); //只读15字节 各个不同文件类型，头信息不一样。

fclose($file);

$typelist=self::$_TypeList;

foreach ($typelist as $v)

{

$blen=strlen(pack("H*",$v[0])); //得到文件头标记字节数

$tbin=substr($bin,0,intval($blen)); ///需要比较文件头长度

if(strtolower($v[0])==strtolower(array_shift(unpack("H*",$tbin))))

{

return $v[1];

}

}

return $filetype;

}

/**

* 得到文件头与文件类型映射表*

*

* @return array array(array('key',value)...)

*/

public function getTypeList()

{

return array(array("FFD8FFE1","jpg"),

array("89504E47","png"),

array("47494638","gif"),

array("49492A00","tif"),

array("424D","bmp"),

array("41433130","dwg"),

array("38425053","psd"),

array("7B5C727466","rtf"),

array("3C3F786D6C","xml"),

array("68746D6C3E","html"),

array("44656C69766572792D646174","eml"),

array("CFAD12FEC5FD746F","dbx"),

array("2142444E","pst"),

array("D0CF11E0","xls/doc"),

array("5374616E64617264204A","mdb"),

array("FF575043","wpd"),

array("252150532D41646F6265","eps/ps"),

array("255044462D312E","pdf"),

array("E3828596","pwl"),

array("504B0304","zip"),

array("52617221","rar"),

array("57415645","wav"),

array("41564920","avi"),

array("2E7261FD","ram"),

array("2E524D46","rm"),

array("000001BA","mpg"),

array("000001B3","mpg"),

array("6D6F6F76","mov"),

array("3026B2758E66CF11","asf"),

array("4D546864","mid"));

}

public static function getFileType($filename)

{

if(!self::$CheckClass) self::$CheckClass=new self($filename);

$class=self::$CheckClass;

return $class->_getFileType($filename);

}

}

调用方法:

$filename="d:/1.png";

echo $filename,"\t",cFileTypeCheck::getFileType($filename),"\r\n";

$filename="d:/test.doc";

echo $filename,"\t",cFileTypeCheck::getFileType($filename),"\r\n";

输出:

d:/1.png png

d:/test.doc xls/doc

通过WinHex软件来获取文件的头信息: 可以看到：png 文件，头是4个字节(头标记是多少字节需要自己查相关资料确定)，对应是：89504E47