-let intersect_ex l1 l2 =
- (* PRE-CLAUDIO
- (*let _ = print_string ("INTERSECT ")
- and t = Unix.time () in*)
- let result =
- match (l1, l2) with
- ((head1::tail1), (head2::tail2)) ->
- (match (head1, head2) with
- ([], _) -> assert false (* gli header non devono mai essere vuoti *)
- | (_, []) -> assert false (* devono contenere almeno [retVal] *)
- | (_, _) ->
- (match (tail1, tail2) with
- ([], _) -> [["retVal"]] (* se una delle due code e' vuota... *)
- | (_, []) -> [["retVal"]] (* ... l'intersezione e' vuota *)
- | (_, _) ->
- [head2 @
- (List.find_all
- (function t -> not (List.mem t head2))
- head1
- )
- ] (* header del risultato finale *)
- @
- intersect_tails (List.tl head1) tail1 (List.tl head2) tail2
- (*
- List.fold_left
- (fun par1 elem1 -> par1 @
- List.map
- (fun elem2 ->
- [(List.hd elem1)] @
- (xres_join_context (List.tl head1) (List.tl elem1)
- (List.tl head2) (List.tl elem2)
- )
- )
- (List.find_all (* *)
- (fun elem2 -> (* trova tutti gli elementi della lista tail2 *)
- ((List.hd elem1) = (List.hd elem2)) && (* che stanno in tail1 *)
- not ((xres_join_context (List.tl head1) (List.tl elem1)
- (List.tl head2) (List.tl elem2)) = [])
- (* e per i quali la xres_join_context non sia vuota *)
- )
- tail2 (* List.find_all *)
- )
- )
- []
- tail1 (* per ogni elemento di tail1 applica la List.fold_left *)
- *)
- ) (* match *)
- )
- | _ -> []
- in
- (*let _ = print_endline (string_of_float (Unix.time () -. t)); flush stdout in*)
- result*)
- let before = Unix.time () in
- let res = intersect_ex l1 l2 in
- let after = Unix.time () in
- let ll1 = string_of_int (List.length l1) in
- let ll2 = string_of_int (List.length l2) in
- let diff = string_of_float (after -. before) in
- prerr_endline
- ("INTERSECT(" ^ ll1 ^ "," ^ ll2 ^ ") = " ^ string_of_int (List.length res) ^
- ": " ^ diff ^ "s") ;
- flush stderr ;
- res
+(* Intersection between two resource sets, preserves order and gets rid of duplicates *)
+let rec intersect_ex rs1 rs2 =
+ match (rs1, rs2) with
+ [],_
+ | _,[] -> []
+ | (uri1,_)::tl1, (uri2,_)::_ when uri1 < uri2 -> intersect_ex tl1 rs2
+ | (uri1,_)::_, (uri2,_)::tl2 when uri2 < uri1 -> intersect_ex rs1 tl2
+ | (uri1,as1)::tl1, (uri2,as2)::tl2 -> (uri1, prod(as1,as2))::intersect_ex tl1 tl2