product or service id en/decode

inv_id_code.php

	// ## invoice id en/decode
	function inv_id_code( $id, $act )
	{
		$str = null;
		
		if ( ( $act == 0 || $act == false ) && ( $id != "" ) && preg_match( "/^\w{16}$/i", $id ) == true )
		{
			foreach( str_split( strrev( $id ), 4 ) as $i => $seg )
			{
				$str .= "-" . strtoupper( strrev( $seg ) ); 
			}

			return "INV2" . $str;
		}
		else if ( ( $act == 1 || $act == true ) && ( $id != "" ) )
		{
			foreach( explode( "-", $id ) as $i => $seg )
			{
				if ( $i > 0 )
				{
					foreach( str_split( strrev( $seg ) ) as $chr )
					{
						$str .= rand( 0, 1 ) ? $chr : strtolower( $chr );
					}					
				}
			}

			return strrev( $str );
		}			
		else
		{
			return false;
		}
	}