<?php

class State {

	protected $varNames, $fileName;

	function __construct(array $varNames, $id = '') {
	
		$id = (string)$id;
	
		$this->varNames = $varNames;
		$this->fileName = '__'.basename($_SERVER['SCRIPT_NAME']).'__'.$id;
	}
	
	function load() {
	
		if (file_exists($this->fileName)) {
	
			$State = unserialize(file_get_contents($this->fileName));
			
			foreach ($State as $varName => $value) {
	
				$GLOBALS[$varName] = $value;
			}
	
			return true;
		}
	
		return false;
	}
	
	function save() {
	
		$State = array();
		
		foreach ($this->varNames as $varName) {
			
			$State[$varName] = @$GLOBALS[$varName];
		}
		
		if ($f = fopen($this->fileName, 'w')) {
			
			fwrite($f, serialize($State));
			fclose($f);
		}
	}
	
	function delete() {
		
		unlink($this->fileName);
	}
}