(**
 	Module: Beam	
	Description: beam definition and operations
	@author WANG Haisheng	
	Created: 21/07/2013	Modified: 21/07/2013
*)

exception Beam_matching of string;;

open Types;;
open Signal;;

class beam : signal_type array -> beam_type = 
  fun (signals_init : signal_type array) ->
    object (self)
      val signals = signals_init

      method get = signals
      method length = Array.length signals

      method sub : int -> int -> beam_type = 
	fun start ->
	  fun len ->
	    new beam (Array.sub self#get start len)

      method append : beam_type -> beam_type =
	fun (b : beam_type) -> 
	  new beam (Array.append self#get b#get)

      method private add_memory : int -> unit =
	fun (window : int) ->
	  let signal_add_memory : int -> signal_type -> unit = 
	    fun (l : int) ->
	      fun (s : signal) ->
		s#add_memory l in
	  let _ = Array.map (signal_add_memory window) self#get in ()
	  
      method matching : int -> beam_type = 
	  fun size ->
	    if size = self#length then new beam self#get

	    else if (size > self#length) && (size mod self#length = 0) then
	      let () = self#add_memory 1 in
	      let split_signals = 
		Array.concat (Array.to_list 
		     (Array.make (size/self#length) self#get)) in
	      new beam split_signals

	    else if (size < self#length) && (self#length mod size = 0) then
	      let rec merge_rec  = 
		fun (sa : signal_type array) ->
		  fun (l : int) ->
		    fun (i : int) ->
		      if i + l < Array.length sa then
			(sa.(i))#add (merge_rec sa l (i + l))
		      else sa.(i) in
	      let merge_signals = Array.init size (merge_rec self#get size) in	
	      new beam merge_signals

	    else raise (Beam_matching "matching size error")

      method time : time -> value_type array = 
	fun t ->
	  let signal_at = fun (t : time) -> fun (s : signal_type) -> s#at t in
	  Array.map (signal_at t) self#get

      method output : int -> (int list) * (float array list) = 
	  
    end