/*
* Class written by Xavier MARTIN (xxlm or zeflasher)
* http://dev.webbymx.net
* http://www.webbymx.net
* If you are using this class, I will be glad to receive a picture of you front of your city hall ( or wherever outside )
* To do so please visit http://dev.webbymx.net and go in the about page to get my details...
* Licence: http://creativecommons.org/licenses/by-nc-sa/2.0/fr/deed.en
*/

class net.webbymx.files.Hexa {
/* ****************************************************************************
* CONSTRUCTOR
**************************************************************************** */	
	private function Hexa() {}
	
/* ****************************************************************************
* PUBLIC STATIC FUNCTIONS
**************************************************************************** */
	private static function fillZeroBytes( s : String ) : String {
		var l : Number;
		
		if ( arguments[ 1 ] != undefined && typeof( arguments[ 1 ] ) == "number" ) l = arguments[ 1 ];
		if ( l == undefined || ( l % 2 != 0 ) ) l = s.length + ( ( s.length % 2 ) )
		
		for ( var i : Number = s.length; i < l; ++i ) s = s + "0";
		
		return s;		
	}
	
/**
* return the Hexa for a byte from 
* @param	s	: the hexa string passed to be encoded to be write in binary files
* @return
*/
	public static function getByte ( s : String ) : String {
		return getString( s, 2 );
	}
	
	
/**
* return the Hexa for a Word ( 2 bytes ) from
* @param	s	: the hexa string passed to be encoded to be write in binary files
* @return	the hexa string encoded
*/	
	public static function getWord ( s : String ) : String {
		return getString( s, 4 );
	}

	
/**
* return the Hexa for a DWord ( 4 bytes ) from
* @param	s	: the hexa string passed to be encoded to be write in binary files
* @return	the hexa string encoded
*/
	public static function getDWord ( s : String ) : String {
		return getString( s, 8 );
	}
	
	
/**
* Get the Hexa from
* @param	s	: the hexa string passed to be encoded to be write in binary files
* @param	l	: the length of the string to be returned
* @return	the hexa string encoded
*/
	
	public static function getString( s : String, l : Number ) : String {
		var r : String = "";
		
	//	if string lenght > 0 then check for bytes and create the string to read from right to left
		while ( s.length > 0 ) {
			if ( s.length >= 2 ) {
				r += s.substring( s.length-2 )
				s = s.slice( 0, s.length-2 )
			} else {
				r += "0" + s;
				s = "";
			}
		}
		
	//	fille the rest of the string with zero
		r = fillZeroBytes(r, l );
		
		return r
	}
	
}