Beautifier for php serialize()

SerializeBeautifier.php

<?php
/**
 * @author Koushik Seal <thekoushik.universe@gmail.com>
 * @version 1.0
 */
class SerializeBeautifier{
	/**
	 * input for beautify
	 * 
	 * @var string
	 */
	private $input;
	/**
	 * current position in input
	 * 
	 * @var int
	 */
	private $pos;
	/**
	 * converts serialized result into an assiciative array
	 * 
	 * @param  string $input output of serialize()
	 * @return array
	 */
	public function beautify($input){
		$this->pos=0;
		$this->input=$input;
		return $this->do_beautify();
	}
	/**
	 * converts array to string as serialized result
	 * 
	 * @param  array $array
	 * @return string
	 */
	public function uglify($array){
		if(!is_array($array))
			throw new Exception("Array expected");
		$str="";
		switch ($array['type']) {
			case 'int':
				$str="i:".$array['value'].";";
				break;
			case 'double':
				$str="d:".$array['value'].";";
				break;
			case 'string':
				$str="s:".strlen($array['value']).":\"".$array['value']."\";";
				break;
			case 'boolean':
				$str="b:".($array['value']==1?'1':'0').";";
				break;
			case 'array':
				$str="a:".count($array['value']).":{";
				foreach ($array['value'] as $key => $value) {
					if(is_string($key))
						$str.="s:".strlen($key).":\"".$key."\";";
					else
						$str.="i:".$key.";";
					$str.=$this->uglify($value);
				}
				$str.="}";
				break;
			case 'object':
				$str.="O:".strlen($array['value']['class']).":\"".$array['value']['class']."\":";
				$array=$array['value']['value'];
				$str.="".count($array).":{";
				foreach ($array as $key => $value) {
					$str.="s:".strlen($key).":\"".$key."\";";

					$str.=$this->uglify($value);
				}
				$str.="}";
				break;
			default:
				throw new Exception("Invalid type \"".$array['type']."\"");
		}
		return $str;
	}
	/**
	 * check whether current character is ';' or '}'
	 * 
	 * @return void
	 */
	private function expectEnd(){
		if($this->input[$this->pos]==';' || $this->input[$this->pos]=='}')
			$this->pos++;
		else
			throw new Exception('Syntax Error: ";" or "}" expected at '.$this->pos);
	}
	/**
	 * check whether current character is ':'
	 * 
	 * @return void
	 */
	private function expectColon(){
		if($this->input[$this->pos++]!=':')
			throw new Exception('Syntax Error: ":"  expected at '.$this->pos);
	}
	/**
	 * check whether current character is '{'
	 * 
	 * @return void
	 */
	private function expectStartObject(){
		if($this->input[$this->pos++]!='{')
			throw new Exception('Syntax Error: "{" expected at '.$this->pos);
	}
	/**
	 * returns the next number from the input
	 * 
	 * @return double
	 */
	private function getNumber(){
		if(preg_match("/[:;]/",$this->input,$match,PREG_OFFSET_CAPTURE,$this->pos)){//^0-9.
			$num=substr($this->input,$this->pos,$match[0][1]-$this->pos);
			$this->pos=$match[0][1];
			return $num;
		}else
			throw new Exception('Syntax Error: at '.$this->pos);
	}
	/**
	 * returns the next character as type
	 * 
	 * @return string
	 */
	private function getType(){
		$type=$this->input[$this->pos++];
		$this->expectColon();
		return $type;
	}
	/**
	 * converts string to array recursively
	 * 
	 * @return array
	 */
	private function do_beautify(){
		$type=$this->getType();
		$size=$this->getNumber();
		switch ($type) {
			case 'i':
				$type='int';
				$val=$size;
				break;
			case 'b':
				if($size<0 || $size>1)
					throw new Exception('Syntax Error: boolean value can only be 0 or 1');
				$type='boolean';
				$val=$size;
				break;
			case 'd':
				$type='double';
				$val=$size;
				break;
			case 's':
				$type='string';
				$this->expectColon();
				$val=substr($this->input,$this->pos+1,$size);
				$this->pos+=$size+2;
				break;
			case 'a':
				$type='array';
				$this->expectColon();
				$this->expectStartObject();
				$array=[];
				for($i=0;$i<$size;$i++){
					$index=$this->do_beautify();
					$v=$this->do_beautify();
					$array[$index['value']]=$v;
				}
				$val=$array;
				break;
			case 'O':
				$type='object';
				$this->expectColon();
				$clazz=substr($this->input,$this->pos+1,$size);
				$this->pos+=$size+2;
				$this->expectColon();
				$propertyCount=$this->getNumber();
				$this->expectColon();
				$this->expectStartObject();
				$array=[];
				for($i=0;$i<$propertyCount;$i++){
					$propertyName=$this->do_beautify();
					$v=$this->do_beautify();
					$array[$propertyName['value']]=$v;
				}
				$val=['class'=>$clazz,'value'=>$array];
				break;
			default:
				throw new Exception("Unexpected type \"".$type."\" at ".$this->pos);
		}
		$this->expectEnd();
		return ['type'=>$type,'value'=>$val];
	}
}
/////////////////////////////test
class Abc{
	private $name;
	private $age;
	public function __construct($name){
		$this->name=$name;
		$this->age=10;
	}
}
date_default_timezone_set('Asia/Kolkata');
$testCases=['new Abc("xyz")'=>new Abc("xyz"),'new DateTime()'=>new DateTime(),'true'=>true,"100"=>100,"3.14159265"=>3.14159265,'simple'=>"simple",'[10,12]'=>[10,12],"['a'=>'assoc','b'=>'array']"=>['a'=>'assoc','b'=>'array']];
foreach ($testCases as $key=>$value){
	$input=serialize($value);
	$beautifier=new SerializeBeautifier();
	$array=$beautifier->beautify($input);
	$output=$beautifier->uglify($array);
	if($input==$output)
		echo $key." (".gettype($value).") -> Success\n";
	else
		echo $key." (".gettype($value).") -> Failure\n".$input."\n".$output."\n";
}

/* Result:
new Abc("xyz") (object) -> Success
new DateTime() (object) -> Success
true (boolean) -> Success
100 (integer) -> Success
3.14159265 (double) -> Success
simple (string) -> Success
[10,12] (array) -> Success
['a'=>'assoc','b'=>'array'] (array) -> Success
*/