INCLUDE "debug.ml"
INCLUDE "utils.ml"

module type S =
  sig
    type t
    type elt = Tree.node
    val empty : t
    val singleton : elt -> t
    val cons : elt -> t -> t
    val snoc : t -> elt -> t
    val concat : t -> t -> t
    val concat3 : t -> t -> t -> t
    val concat4 : t -> t -> t -> t -> t
    val conscat : elt -> t -> t -> t
    val conscat3 : elt -> t -> t -> t -> t
    val conscat4 : elt -> t -> t -> t -> t -> t
    val subtree_tags : Tree.t -> elt -> Tag.t -> t
    val subtree_elements : Tree.t -> elt -> t
    val iter : ( elt -> unit) -> t -> unit
    val fold : ( elt -> 'a -> 'a) -> t -> 'a -> 'a
    val length : t -> int
    val serialize : string -> Tree.t -> t -> unit
  end

module Count : S with type t = int =
  struct
    type t = int
    type elt = Tree.node

    let empty = 0
    let singleton _ = 1
    let cons _ x = x+1
    let snoc x _ = x+1
    let concat x y = x + y
    let concat3 x y z = x + y + z
    let concat4 x y z t = x + y + z + t
    let conscat _ x y = 1 + x + y
    let conscat3 _ x y z = 1 + x + y + z
    let conscat4 _ x y z t = 1 + x + y + z + t
    let subtree_tags tree node tag = Tree.subtree_tags tree node tag
    let subtree_elements tree node = Tree.subtree_elements tree node
    let iter _ _ = failwith "iter not implemented"
    let fold _ _ _ = failwith "fold not implemented"
    let map _ _ = failwith "map not implemented"
    let length x = x
    let serialize _ _ _ = ()
  end

type  clist =
  | Nil
  | Cons of Tree.node * clist
  | Concat of clist * clist
  | ConsCat of Tree.node * clist * clist
  | SubtreeTags of Tree.t * Tree.node * Tag.t
  | SubtreeElts of Tree.t * Tree.node


type 'a mat = { mutable clist : clist;
	        mutable length : int }

module Mat : S with type t = Tree.node mat =
  struct
    type t = Tree.node mat
    type elt = Tree.node

    let empty = { clist = Nil; length = 0 }
    let singleton e = { clist = Cons(e, Nil) ; length = 1 }
    let cons e l = { clist = Cons(e, l.clist); length = l.length + 1 }
    let concat l1 l2 =
      let ll1 = l1.length in
      if ll1 == 0 then l2 else
	let ll2 = l2.length in if ll2 == 0 then l1 else
	    { clist = Concat(l1.clist, l2.clist); length = ll1 + ll2 }

    let snoc l e = concat l (singleton e)
(*
    let _total = ref 0
    let _empty = ref 0
    let () = at_exit (fun () -> Printf.eprintf "Dummy concatenations: %i/%i\n%!" !_empty !_total)

    let concat l1 l2 =
      let l = concat l1 l2 in
      if l.length == 0 then incr _empty;
      incr _total;
      l
*)
    let concat3 l1 l2 l3 = concat l1 (concat l2 l3)
    let concat4 l1 l2 l3 l4 = concat (concat l1 l2) (concat l3 l4)


    let conscat e l1 l2 =
      let ll1 = l1.length in
      if ll1 == 0 then cons e l2 else
	let ll2 = l2.length in if ll2 == 0 then cons e l1 else
	    { clist = ConsCat(e, l1.clist, l2.clist); length = 1 + ll1 + ll2 }

(*    let conscat e l1 l2 = cons e (concat l1 l2) *)

    let conscat3 e l1 l2 l3 = conscat e l1 (concat l2 l3)
    let conscat4 e l1 l2 l3 l4 = conscat e l1 (concat l2 (concat l3 l4))

    let subtree_tags tree node tag =
      { clist = SubtreeTags(tree, node, tag);
	length = Tree.subtree_tags tree node tag }
    let subtree_elements tree node =
      { clist = SubtreeElts(tree, node);
	length = Tree.subtree_elements tree node }

    let fst_tagged tree t tag =
      if Tree.tag tree t == tag then t
      else Tree.tagged_descendant tree t tag

    let fst_element tree t =
      let tag = Tree.tag tree t in
      let t = if Ptset.Int.mem tag
	  (Ptset.Int.remove Tag.document_node (Tree.element_tags tree))
	then t
	else Tree.first_element tree t
      in Tree.first_element tree t

    let element_fold f tree t acc =
      let rec loop node acc =
	if node == Tree.nil then acc
	else
	  let acc = f node acc in
	  let acc' = loop (Tree.first_element tree node) acc in
	    loop (Tree.next_element tree node) acc'
      in
	loop (fst_element tree t) acc

    let element_iter f tree t =
      let rec loop node =
	if node != Tree.nil then begin
	  f node;
	  loop (Tree.first_element tree node);
	  loop (Tree.next_element tree node)
	end
      in
      let t' = fst_element tree t in loop t'

    let tag_fold f tree t tag acc =
      let rec loop close node acc =
	if node == Tree.nil then acc
	else
	  let acc = f node acc in
	  let acc' = loop close (Tree.tagged_descendant tree node tag) acc in
	    loop close (Tree.tagged_following_before tree node tag close) acc'
      in
      let t = fst_tagged tree t tag in
	loop (Tree.closing tree t) t acc

    let tag_iter f tree t tag =
      let rec loop close node =
	if node != Tree.nil then begin
	  f node;
	  loop close (Tree.tagged_descendant tree node tag);
	  loop close (Tree.tagged_following_before tree node tag close);
	end
      in
      let t' = fst_tagged tree t tag in
	loop (Tree.closing tree t) t'

    let fold f l acc =
      let rec loop l acc =
	match l with
	  | Nil -> acc
	  | Cons(e, ll) -> loop ll (f e acc)
	  | Concat(l1, l2) -> loop l2 (loop l1 acc)
	  | ConsCat(e, l1, l2) -> loop l2 (loop l1 (f e acc))
	  | SubtreeTags(tree, t, tag) -> tag_fold f tree t tag acc
	  | SubtreeElts(tree, t) -> element_fold f tree t acc
      in
	loop l.clist acc

    let iter f l =
      let rec loop l =
	match l with
	  | Nil -> ()
	  | Cons(e, l) -> f e; loop l
	  | Concat(l1, l2) -> loop l1; loop l2
	  | ConsCat(e, l1, l2) -> f e; loop l1; loop l2
	  | SubtreeTags(tree, t, tag) -> tag_iter f tree t tag
	  | SubtreeElts(tree, t) ->
	      element_iter f tree t
      in
	loop l.clist

    let length l = l.length

    let serialize name v l =
      let fd, finish =
	if name = "-" then Unix.stdout, ignore
	else
	  Unix.openfile name [ Unix.O_WRONLY; Unix.O_TRUNC; Unix.O_CREAT ] 0o666,
	  Unix.close
      in
      iter (fun node -> Tree.print_xml v node fd) l;
      Tree.flush v fd;
      finish fd

  end
let rec debug_clist =
  function
      Nil -> Printf.eprintf "Nil"
    | Cons(e, clist) ->
	Printf.eprintf "Cons(%i," (Obj.magic e);
	debug_clist clist;
	Printf.eprintf ")";
    | Concat(clist1, clist2) ->
	    Printf.eprintf "Concat(";
	debug_clist clist1;
	Printf.eprintf ",";
	    debug_clist clist2;
	    Printf.eprintf ")";
    | ConsCat(_, clist1, clist2) ->
	    Printf.eprintf "Concat(";
	debug_clist clist1;
	Printf.eprintf ",";
	    debug_clist clist2;
	    Printf.eprintf ")";

    | SubtreeTags(tree, node, tag) ->
	Printf.eprintf "SubtreeTags(tree, %i, %s)"
	  (Obj.magic node)
	  (Tag.to_string tag);
    | SubtreeElts(tree, node) ->
	Printf.eprintf "SubtreeElts(tree, %i)"
	  (Obj.magic node)

let debug l = debug_clist l.clist