zproto for php parse

zproto.php

class zproto {
	private $proto;
	private $unpack;
	function __construct($dom) {
		$this->proto = $dom;
	}
	//for compatible less then 7.1.0
	private function unpack($fmt, $dat, $off) {
		$dat = substr($dat, $off);
		return unpack($fmt, $dat);
	}
	public function parse($dat, $name) {
		$tag = 0;
		$tagoff = 6;
		$ret = array();
		$proto = $this->proto[$name];
		$sz = $this->unpack('L', $dat, 0)[1];
		$fn = $this->unpack('S', $dat, 4)[1];
		$off = $tagoff + $fn * 2;
		for ($i = 0; $i < $fn; $i++) {
			$t = $this->unpack('S', $dat, $tagoff)[1]; $tagoff += 2;
			$t = $tag + 1;
			$field = $proto[$t];
			switch ($field['type']) {
			case 'byte':
				$v = $this->unpack('c', $dat, $off)[1]; $off += 4;
				break;
			case 'ubyte':
				$v = $this->unpack('C', $dat, $off)[1]; $off += 4;
				break;
			case 'integer':
				$v = $this->unpack('l', $dat, $off)[1]; $off += 4;
				break;
			case 'uinteger':
				$v = $this->unpack('V', $dat, $off)[1]; $off += 4;
				break;
			case 'long':
				$v = $this->unpack('q', $dat, $off)[1]; $off += 8;
				break;
			case 'ulong':
				$v = $this->unpack('Q', $dat, $off)[1]; $off += 8;
				break;
			case 'string':
				$len = $this->unpack('L', $dat, $off)[1]; $off += 4;
				$v = substr($dat, $off, $len);  $off += $len;
				break;
			default:
				$len = $this->unpack('L', $dat, $off)[1];
				$x = substr($dat, $off);
				$v = $this->parse($x, $field['type']);
				$off += $len + 4;
				break;
			}
			$ret[$field['name']] = $v;
			$tag = $t;
		}
		return $ret;
	}
};

$str = "\x04\x00\x00\x00\x02\x00\x00\x00\x00\x00\x04\x00\x00\x00\x02\x00\x00\x00ab";
$proto = [
	'foo'=>array(
		1=>["name"=>"foo", "type" => "uinteger"],
		2=>["name"=>"foo", "type" => "string"],
	),
];

$obj = new zproto($proto);
$arr = $obj->parse($str, "foo");
echo var_dump($arr);