<?php

/**
 * Class for storing key=value database in binary file
 *
 */
class FileStorage {
	/**
	 * Protected filename
	 *
	 * @var string
	 */
	protected $fileName;
	/**
	 * Constructor. 
	 *
	 * @param string $fileName
	 */
	public function __construct($fileName) {
		$this->fileName = $fileName;
	}
	/**
	 * Getting value from from by key
	 *
	 * @param string $key
	 * @return mixed
	 */
	public function get($key) {
		if (file_exists($this->fileName)) {
			$handle = fopen($this->fileName,"rb");
			$contents = '';
			$res = null;
			while (!feof($handle)) {
			  $contents .= fread($handle, 8192);
			}
			fclose($handle);
			if (!empty($contents))	{		
				$res = unserialize($contents);
				if (is_array($res)) {
					if (array_key_exists($key,$res)) {
						return $res[$key];
					}
				}
			}
		}
		return null;
	}
	/**
	 * Setting value and storing it into file
	 *
	 * @param string $key
	 * @param mixed $value
	 * @return bool
	 */
	public function set($key,$value) {
		if (file_exists($this->fileName)) {
			$handle = fopen($this->fileName,"rb");
			$contents = '';
			$res = null;
			while (!feof($handle)) {
			  $contents .= fread($handle, 8192);
			}
			fclose($handle);
			if (!empty($contents))	{		
				$res = unserialize($contents);
			}
			if (is_array($res)) {
				$res[$key] = $value;
			}
			else {
				$res = array($key => $value);
			}
			
			$wres = serialize($res);
			if(is_writable($this->fileName)) {
				$handle = fopen($this->fileName,"wb");
				fwrite($handle,$wres);
				fclose($handle);
				return true;
			}
		}
		return false;
	}
}


/**

	How to use it?
	
	Store value in fb.txt:
 
	$f = new FileStorage(dirname(__FILE__).'/fb.txt');
  $f->set($var_name,$var_value);
	
	
	Read this value later:
	
  $f = new FileStorage(dirname(__FILE__).'/fb.txt');
  $value = $f->get($var_name);

	
*/
?>