types.ml 48.7 KB
Newer Older
1
open Ident
2
open Encodings
3

4 5 6 7 8
(* TODO:
   - I store hash in types to avoid computing it several times.
     Does not seem to help a lot.
*)

9 10 11 12 13 14 15 16 17 18
(*
To be sure not to use generic comparison ...
*)
let (=) : int -> int -> bool = (==)
let (<) : int -> int -> bool = (<)
let (<=) : int -> int -> bool = (<=)
let (<>) : int -> int -> bool = (<>)
let compare = 1


19 20 21
module CompUnit = struct   
  include Pool.Make(Utf8)
  module Tbl = Inttbl
22
      
23
  let pervasives = mk (U.mk "Pervasives") 
24
      
25
  let close_serialize_ref = ref (fun () -> assert false)
26
      
27
  let depend = Inttbl.create ()
28
      
29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
  let serialize t cu =
    if cu != pervasives then Inttbl.add depend cu ();
    serialize t cu

  let close_serialize () =
    !close_serialize_ref ();
    let deps = Inttbl.fold depend (fun cu () l -> cu :: l) [] in
    Inttbl.clear depend;
    deps


  let stack = ref []
  let current = ref dummy_min
		
  let enter i = stack := !current :: !stack; current := i
		  
  let leave () =
    match !stack with
      | hd::tl -> current := hd; stack := tl
      | _ -> assert false


  let () = enter pervasives
end	  


55
type const = 
56
  | Integer of Intervals.V.t
57
  | Atom of Atoms.V.t 
58
  | Char of Chars.V.t
59 60 61 62
  | Pair of const * const
  | Xml of const * const
  | Record of const label_map
  | String of U.uindex * U.uindex * U.t * const
63

64 65 66
module Const = struct
  type t = const

67 68 69 70 71 72 73 74 75 76 77
  let rec check = function
    | Integer i -> Intervals.V.check i
    | Atom i -> Atoms.V.check i
    | Char i -> Chars.V.check i
    | Pair (x,y) | Xml (x,y) -> check x; check y
    | Record l -> LabelMap.iter check l
    | String (i,j,s,q) -> U.check s; check q

  let dump ppf _ =
    Format.fprintf ppf "<Types.Const.t>"

78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109
  let rec serialize s = function
    | Integer x ->
	Serialize.Put.bits 3 s 0;
	Intervals.V.serialize s x
    | Atom x ->
	Serialize.Put.bits 3 s 1;
	Atoms.V.serialize s x
    | Char x ->
	Serialize.Put.bits 3 s 2;
	Chars.V.serialize s x
    | Pair (x,y) ->
	Serialize.Put.bits 3 s 3;
	serialize s x;
	serialize s y
    | Xml (x,y) ->
	Serialize.Put.bits 3 s 4;
	serialize s x;
	serialize s y
    | Record r ->
	Serialize.Put.bits 3 s 5;
	LabelMap.serialize serialize s r
    | String (i,j,st,q) ->
	Serialize.Put.bits 3 s 6;
	U.serialize_sub s st i j;
	serialize s q

  let rec deserialize s =
    match Serialize.Get.bits 3 s with
      | 0 ->
	  Integer (Intervals.V.deserialize s)
      | 1 ->
	  Atom (Atoms.V.deserialize s)
110 111
      | 2 ->
	  Char (Chars.V.deserialize s)
112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
      | 3 ->
	  let x = deserialize s in
	  let y = deserialize s in
	  Pair (x,y)
      | 4 ->
	  let x = deserialize s in
	  let y = deserialize s in
	  Xml (x,y)
      | 5 ->
	  Record (LabelMap.deserialize deserialize s)
      | 6 ->
	  let st = U.deserialize s in
	  let q = deserialize s in
	  String (U.start_index st, U.end_index st, st, q)
      | _ ->
	  assert false

  let rec compare c1 c2 = match (c1,c2) with
130
    | Integer x, Integer y -> Intervals.V.compare x y
131 132
    | Integer _, _ -> -1
    | _, Integer _ -> 1
133
    | Atom x, Atom y -> Atoms.V.compare x y
134 135
    | Atom _, _ -> -1
    | _, Atom _ -> 1
136
    | Char x, Char y -> Chars.V.compare x y
137 138 139
    | Char _, _ -> -1
    | _, Char _ -> 1
    | Pair (x1,x2), Pair (y1,y2) ->
140 141
	let c = compare x1 y1 in
	if c <> 0 then c else compare x2 y2
142 143 144
    | Pair (_,_), _ -> -1
    | _, Pair (_,_) -> 1
    | Xml (x1,x2), Xml (y1,y2) ->
145 146
	let c = compare x1 y1 in
	if c <> 0 then c else compare x2 y2
147 148 149
    | Xml (_,_), _ -> -1
    | _, Xml (_,_) -> 1
    | Record x, Record y ->
150
	LabelMap.compare compare x y
151 152 153 154 155 156 157
    | Record _, _ -> -1
    | _, Record _ -> 1
    | String (i1,j1,s1,r1), String (i2,j2,s2,r2) ->
	let c = Pervasives.compare i1 i2 in if c <> 0 then c 
	else let c = Pervasives.compare j1 j2 in if c <> 0 then c
	else let c = U.compare s1 s2 in if c <> 0 then c (* Should compare
							    only the substring *)
158 159 160 161 162 163 164 165 166 167
	else compare r1 r2

  let rec hash = function
    | Integer x -> 1 + 17 * (Intervals.V.hash x)
    | Atom x -> 2 + 17 * (Atoms.V.hash x)
    | Char x -> 3 + 17 * (Chars.V.hash x)
    | Pair (x,y) -> 4 + 17 * (hash x) + 257 * (hash y)
    | Xml (x,y) -> 5 + 17 * (hash x) + 257 * (hash y)
    | Record x -> 6 + 17 * (LabelMap.hash hash x)
    | String (i,j,s,r) -> 7 + 17 * (U.hash s) + 257 * hash r
168
      (* Note: improve hash for String *)
169

170 171
  let equal c1 c2 = compare c1 c2 = 0
end
172

173 174
type pair_kind = [ `Normal | `XML ]

175

176 177 178 179 180 181 182 183 184
module rec Descr : 
sig
(*
  Want to write:
    type s = { ... }
    include Custom.T with type t = s
  but a  bug in OCaml 3.07+beta 2 makes it impossible
*)
  type t = {
185
    mutable hash: int;
186 187 188 189 190 191 192 193 194
    atoms : Atoms.t;
    ints  : Intervals.t;
    chars : Chars.t;
    times : BoolPair.t;
    xml   : BoolPair.t;
    arrow : BoolPair.t;
    record: BoolRec.t;
    absent: bool
  }
195
  val empty: t
196 197 198 199 200 201 202 203 204 205
  val dump: Format.formatter -> t -> unit
  val check: t -> unit
  val equal: t -> t -> bool
  val hash: t -> int
  val compare:t -> t -> int
  val serialize: t Serialize.Put.f
  val deserialize: t Serialize.Get.f
end =
struct
  type t = {
206
    mutable hash: int;
207 208 209 210 211 212 213 214 215
    atoms : Atoms.t;
    ints  : Intervals.t;
    chars : Chars.t;
    times : BoolPair.t;
    xml   : BoolPair.t;
    arrow : BoolPair.t;
    record: BoolRec.t;
    absent: bool
  }
216

217 218 219
  let dump ppf _ =
    Format.fprintf ppf "<Types.Descr.t>"

220 221 222 223 224 225 226 227 228 229 230 231
  let empty = { 
    hash = 0;
    times = BoolPair.empty; 
    xml   = BoolPair.empty; 
    arrow = BoolPair.empty; 
    record= BoolRec.empty;
    ints  = Intervals.empty;
    atoms = Atoms.empty;
    chars = Chars.empty;
    absent= false;
  }

232
  let equal a b =
233 234 235 236 237 238 239 240 241 242
    (a == b) || (
      (Atoms.equal a.atoms b.atoms) &&
      (Chars.equal a.chars b.chars) &&
      (Intervals.equal a.ints  b.ints) &&
      (BoolPair.equal a.times b.times) &&
      (BoolPair.equal a.xml b.xml) &&
      (BoolPair.equal a.arrow b.arrow) &&
      (BoolRec.equal a.record b.record) &&
      (a.absent == b.absent)
    )
243 244 245 246 247 248 249 250 251 252 253 254 255

  let compare a b =
    if a == b then 0 
    else let c = Atoms.compare a.atoms b.atoms in if c <> 0 then c
    else let c = Chars.compare a.chars b.chars in if c <> 0 then c
    else let c = Intervals.compare a.ints b.ints in if c <> 0 then c
    else let c = BoolPair.compare a.times b.times in if c <> 0 then c
    else let c = BoolPair.compare a.xml b.xml in if c <> 0 then c
    else let c = BoolPair.compare a.arrow b.arrow in if c <> 0 then c
    else let c = BoolRec.compare a.record b.record in if c <> 0 then c
    else if a.absent && not b.absent then -1
    else if b.absent && not a.absent then 1
    else 0
256
      
257
  let hash a =
258 259 260 261 262 263 264 265 266 267 268 269
    if a.hash <> 0 then a.hash else (
      let accu = Chars.hash a.chars in
      let accu = 17 * accu + Intervals.hash a.ints in
      let accu = 17 * accu + Atoms.hash a.atoms in
      let accu = 17 * accu + BoolPair.hash a.times in
      let accu = 17 * accu + BoolPair.hash a.xml in
      let accu = 17 * accu + BoolPair.hash a.arrow in
      let accu = 17 * accu + BoolRec.hash a.record in
      let accu = if a.absent then accu+5 else accu in
      a.hash <- accu;
      accu
    )
270

271 272 273 274 275 276 277 278 279 280 281
  let check a =
    Chars.check a.chars;
    Intervals.check a.ints;
    Atoms.check a.atoms;
    BoolPair.check a.times;
    BoolPair.check a.xml;
    BoolPair.check a.arrow;
    BoolRec.check a.record;
    ()


282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
  let serialize t a =
    Chars.serialize t a.chars;
    Intervals.serialize t a.ints;
    Atoms.serialize t a.atoms;
    BoolPair.serialize t a.times;
    BoolPair.serialize t a.xml;
    BoolPair.serialize t a.arrow;
    BoolRec.serialize t a.record;
    Serialize.Put.bool t a.absent 

  let deserialize t =
    let chars = Chars.deserialize t in
    let ints = Intervals.deserialize t in
    let atoms = Atoms.deserialize t in
    let times = BoolPair.deserialize t in
    let xml = BoolPair.deserialize t in
    let arrow = BoolPair.deserialize t in
    let record = BoolRec.deserialize t in
    let absent = Serialize.Get.bool t in
301
    let d = { hash=0; 
302
      chars = chars; ints = ints; atoms = atoms; times = times; xml = xml;
303 304 305
      arrow = arrow; record = record; absent = absent } in
    check d;
    d
306 307
   
    
308 309 310
end
and Node :
sig
311
  type t = { id : int; comp_unit: CompUnit.t; mutable descr : Descr.t }
312 313 314 315 316 317 318
  val dump: Format.formatter -> t -> unit
  val check: t -> unit
  val equal: t -> t -> bool
  val hash: t -> int
  val compare:t -> t -> int
  val serialize: t Serialize.Put.f
  val deserialize: t Serialize.Get.f
319
  val mk: int -> Descr.t -> t
320
end =
321

322
struct
323
  type t = { id : int; comp_unit : CompUnit.t; mutable descr : Descr.t }
324 325
  let check n = ()
  let dump ppf n = failwith "Types.Node.dump"
326 327 328 329
  let hash x = x.id + 17 * x.comp_unit
  let compare x y = 
    let c = x.id - y.id in
    if c = 0 then x.comp_unit - y.comp_unit else c
330
  let equal x y = x == y
331

332 333 334 335 336 337 338 339
  let serialize_memo = Inttbl.create ()
  let counter_serialize = ref 0

  let () =
    CompUnit.close_serialize_ref := 
    (fun () ->
       Inttbl.clear serialize_memo;
       counter_serialize := 0)
340

341
  let serialize t n = 
342 343 344 345 346 347 348 349 350 351 352 353 354 355 356
    if n.comp_unit == !CompUnit.current then (
      Serialize.Put.bool t true;
      try 
	let i = Inttbl.find serialize_memo n.id in
	Serialize.Put.int t i
      with Not_found ->
	let i = !counter_serialize in
	incr counter_serialize;
	Inttbl.add serialize_memo n.id i;
	Serialize.Put.int t i;
	Descr.serialize t n.descr
    ) else (
      Serialize.Put.bool t false;
      CompUnit.serialize t n.comp_unit;
      Serialize.Put.int t n.id
357
    )
358
      
359

360 361 362 363
  let deserialize_memo = Inttbl.create ()

  let find_tbl id =
    try Inttbl.find deserialize_memo id
364
    with Not_found ->
365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391
      let tbl = Inttbl.create () in
      Inttbl.add deserialize_memo id tbl;
      tbl

  let mk id d =
    let n = { id = id; comp_unit = !CompUnit.current; descr = d } in
    if !CompUnit.current == CompUnit.pervasives then
      Inttbl.add (find_tbl CompUnit.pervasives) n.id n;
    n

  let deserialize t = 
    if Serialize.Get.bool t then
      let i = Serialize.Get.int t in
      let tbl = find_tbl !CompUnit.current in
      try Inttbl.find tbl i
      with Not_found ->
	let n = { id = i; comp_unit = !CompUnit.current;
		  descr = Descr.empty } in
	Inttbl.add tbl i n;
	n.descr <- Descr.deserialize t;
	n
    else
      let cu = CompUnit.deserialize t in
      let i = Serialize.Get.int t in
      try Inttbl.find (Inttbl.find deserialize_memo cu) i 
      with Not_found -> assert false

392 393
end

394
(* It is also possible to use Boolean instead of Bool here;
395
   need to analyze when each one is more efficient *)
396 397 398 399 400 401
and BoolPair : Bool.S with type elem = Node.t * Node.t = 
Bool.Make(Custom.Pair(Node)(Node))

and BoolRec : Bool.S with type elem = bool * Node.t label_map =
Bool.Make(Custom.Pair(Custom.Bool)(LabelSet.MakeMap(Node)))

402 403 404 405
module DescrHash = Hashtbl.Make(Descr)
module DescrMap = Map.Make(Descr)
module DescrSet = Set.Make(Descr)
module DescrSList = SortedList.Make(Descr)
406

407 408 409
type descr = Descr.t
type node = Node.t
include Descr
410 411 412

let hash_cons = DescrHash.create 17000  

413 414 415 416 417 418 419 420 421 422
let count = State.ref "Types.count" 0
		
let () =
  Stats.register Stats.Summary
    (fun ppf -> Format.fprintf ppf "Allocated type nodes:%i@\n" !count)
      
let make () = 
  incr count; 
  Node.mk !count empty

423 424 425 426 427 428 429
let define n d = 
  DescrHash.add hash_cons d n; 
  n.Node.descr <- d
let cons d = 
  try DescrHash.find hash_cons d 
  with Not_found ->
    incr count; 
430
    let n = Node.mk !count d in
431 432
    DescrHash.add hash_cons d n; n  

433
let any =  {
434
  hash = 0;
435 436 437
  times = BoolPair.full; 
  xml   = BoolPair.full; 
  arrow = BoolPair.full; 
438
  record= BoolRec.full; 
439 440 441
  ints  = Intervals.any;
  atoms = Atoms.any;
  chars = Chars.any;
442
  absent= false;
443
}
444 445

let non_constructed =
446 447 448
  { any with  
      hash = 0;
      times = empty.times; xml = empty.xml; record = empty.record }
449
     
450
	     
451 452 453 454
let interval i = { empty with hash = 0; ints = i }
let times x y = { empty with hash = 0; times = BoolPair.atom (x,y) }
let xml x y = { empty with hash = 0; xml = BoolPair.atom (x,y) }
let arrow x y = { empty with hash = 0; arrow = BoolPair.atom (x,y) }
455
let record label t = 
456 457
  { empty with hash = 0; 
      record = BoolRec.atom (true,LabelMap.singleton label t) }
458
let record' (x : bool * node Ident.label_map) =
459 460 461
  { empty with hash = 0; record = BoolRec.atom x }
let atom a = { empty with hash = 0; atoms = a }
let char c = { empty with hash = 0; chars = c }
462
      
463 464
let cup x y = 
  if x == y then x else {
465
    hash = 0;
466 467 468
    times = BoolPair.cup x.times y.times;
    xml   = BoolPair.cup x.xml y.xml;
    arrow = BoolPair.cup x.arrow y.arrow;
469
    record= BoolRec.cup x.record y.record;
470 471 472
    ints  = Intervals.cup x.ints  y.ints;
    atoms = Atoms.cup x.atoms y.atoms;
    chars = Chars.cup x.chars y.chars;
473
    absent= x.absent || y.absent;
474 475 476 477
  }
    
let cap x y = 
  if x == y then x else {
478
    hash = 0;
479 480
    times = BoolPair.cap x.times y.times;
    xml   = BoolPair.cap x.xml y.xml;
481
    record= BoolRec.cap x.record y.record;
482
    arrow = BoolPair.cap x.arrow y.arrow;
483 484 485
    ints  = Intervals.cap x.ints  y.ints;
    atoms = Atoms.cap x.atoms y.atoms;
    chars = Chars.cap x.chars y.chars;
486
    absent= x.absent && y.absent;
487 488 489 490
  }
    
let diff x y = 
  if x == y then empty else {
491
    hash = 0;
492 493 494
    times = BoolPair.diff x.times y.times;
    xml   = BoolPair.diff x.xml y.xml;
    arrow = BoolPair.diff x.arrow y.arrow;
495
    record= BoolRec.diff x.record y.record;
496 497 498
    ints  = Intervals.diff x.ints  y.ints;
    atoms = Atoms.diff x.atoms y.atoms;
    chars = Chars.diff x.chars y.chars;
499
    absent= x.absent && not y.absent;
500 501
  }
    
502

503

504

505 506 507 508 509 510 511 512
(* TODO: optimize disjoint check for boolean combinations *)
let trivially_disjoint a b =
  (Chars.disjoint a.chars b.chars) &&
  (Intervals.disjoint a.ints b.ints) &&
  (Atoms.disjoint a.atoms b.atoms) &&
  (BoolPair.trivially_disjoint a.times b.times) &&
  (BoolPair.trivially_disjoint a.xml b.xml) &&
  (BoolPair.trivially_disjoint a.arrow b.arrow) &&
513 514
  (BoolRec.trivially_disjoint a.record b.record) &&
  (not (a.absent && b.absent))
515

516

517

518
let descr n = n.Node.descr
519
let internalize n = n
520
let id n = n.Node.id
521 522


523 524 525 526 527 528 529 530 531 532 533 534 535
let rec constant = function
  | Integer i -> interval (Intervals.atom i)
  | Atom a -> atom (Atoms.atom a)
  | Char c -> char (Chars.atom c)
  | Pair (x,y) -> times (const_node x) (const_node y)
  | Xml (x,y) -> times (const_node x) (const_node y)
  | Record x -> record' (false ,LabelMap.map const_node x)
  | String (i,j,s,c) ->
      if U.equal_index i j then constant c
      else 
	let (ch,i') = U.next s i in
	constant (Pair (Char (Chars.V.mk_int ch), String (i',j,s,c)))
and const_node c = cons (constant c)
536

537 538
let neg x = diff any x

539 540
let any_node = cons any

541
module LabelS = Set.Make(LabelPool)
542

543 544 545
let any_or_absent = { any with hash=0; absent = true } 
let only_absent = { empty with hash=0; absent = true }

546 547
let get_record r =
  let labs accu (_,r) = 
548 549
    List.fold_left 
      (fun accu (l,_) -> LabelS.add l accu) accu (LabelMap.get r) in
550
  let extend descrs labs (o,r) =
551 552 553 554 555
    let rec aux i labs r =
      match labs with
	| [] -> ()
	| l1::labs ->
	    match r with
556
	      | (l2,x)::r when l1 == l2 -> 
557 558 559
		  descrs.(i) <- cap descrs.(i) (descr x);
		  aux (i+1) labs r
	      | r ->
560 561
		  if not o then 
		    descrs.(i) <- cap descrs.(i) only_absent; (* TODO:OPT *)
562 563
		  aux (i+1) labs r
    in
564
    aux 0 labs (LabelMap.get r);
565 566 567 568
    o
  in
  let line (p,n) =
    let labels = 
569 570
      List.fold_left labs (List.fold_left labs LabelS.empty p) n in
    let labels = LabelS.elements labels in
571
    let nlab = List.length labels in
572
    let mk () = Array.create nlab any_or_absent in
573 574 575 576 577 578 579 580 581 582 583 584 585 586 587

    let pos = mk () in
    let opos = List.fold_left 
		 (fun accu x -> 
		    (extend pos labels x) && accu)
		 true p in
    let p = (opos, pos) in

    let n = List.map (fun x ->
			let neg = mk () in
			let o = extend neg labels x in
			(o,neg)
		     ) n in
    (labels,p,n)
  in
588
  List.map line (BoolRec.get r)
589
   
590

591

592 593 594 595 596 597 598


(* Subtyping algorithm *)

let diff_t d t = diff d (descr t)
let cap_t d t = cap d (descr t)
let cup_t d t = cup d (descr t)
599
let cap_product any_left any_right l =
600 601
  List.fold_left 
    (fun (d1,d2) (t1,t2) -> (cap_t d1 t1, cap_t d2 t2))
602
    (any_left,any_right)
603
    l
604
let any_pair = { empty with hash = 0; times = any.times }
605

606

607 608 609
let rec exists max f =
  (max > 0) && (f (max - 1) || exists (max - 1) f)

610
exception NotEmpty
611

612 613 614 615 616 617 618 619 620 621 622 623
type slot = { mutable status : status; 
	       mutable notify : notify;
	       mutable active : bool }
and status = Empty | NEmpty | Maybe
and notify = Nothing | Do of slot * (slot -> unit) * notify

let slot_empty = { status = Empty; active = false; notify = Nothing }
let slot_not_empty = { status = NEmpty; active = false; notify = Nothing }

let rec notify = function
  | Nothing -> ()
  | Do (n,f,rem) -> 
624
      if n.status == Maybe then (try f n with NotEmpty -> ());
625 626 627 628 629 630 631 632 633 634
      notify rem

let rec iter_s s f = function
  | [] -> ()
  | arg::rem -> f arg s; iter_s s f rem


let set s =
  s.status <- NEmpty;
  notify s.notify;
635
  s.notify <- Nothing; 
636 637 638 639 640 641 642
  raise NotEmpty

let rec big_conj f l n =
  match l with
    | [] -> set n
    | [arg] -> f arg n
    | arg::rem ->
643 644 645
	let s = 
	  { status = Maybe; active = false; 
	    notify = Do (n,(big_conj f rem), Nothing) } in
646 647 648
	try 
	  f arg s;
	  if s.active then n.active <- true
649
	with NotEmpty -> if n.status == NEmpty then raise NotEmpty
650

651 652
let guard a f n =
  match a with
653
    | { status = Empty } -> ()
654 655 656
    | { status = Maybe } as s -> 
	n.active <- true; 
	s.notify <- Do (n,f,s.notify)
657
    | { status = NEmpty } -> f n
658

659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756

(* Fast approximation *)

module ClearlyEmpty = 
struct

let memo = DescrHash.create 33000
let marks = ref [] 

let rec slot d =
  if not ((Intervals.is_empty d.ints) && 
	  (Atoms.is_empty d.atoms) &&
	  (Chars.is_empty d.chars) &&
	  (not d.absent)) then slot_not_empty 
  else try DescrHash.find memo d
  with Not_found ->
    let s = { status = Maybe; active = false; notify = Nothing } in
    DescrHash.add memo d s;
    (try
       iter_s s check_times (BoolPair.get d.times);  
       iter_s s check_xml (BoolPair.get d.xml); 
       iter_s s check_arrow (BoolPair.get d.arrow);
       iter_s s check_record (get_record d.record);
       if s.active then marks := s :: !marks else s.status <- Empty;
     with
	 NotEmpty -> ());
    s

and check_times (left,right) s =
  let (accu1,accu2) = cap_product any any left in
  let single_right (t1,t2) s =
    let t1 = descr t1 and t2 = descr t2 in
    if trivially_disjoint accu1 t1 || trivially_disjoint accu2 t2 then set s 
    else
      let accu1 = diff accu1 t1 in guard (slot accu1) set s;
      let accu2 = diff accu2 t2 in guard (slot accu2) set s in
  guard (slot accu1) (guard (slot accu2) (big_conj single_right right)) s

and check_xml (left,right) s =
  let (accu1,accu2) = cap_product any any_pair left in
  let single_right (t1,t2) s =
    let t1 = descr t1 and t2 = descr t2 in
    if trivially_disjoint accu1 t1 || trivially_disjoint accu2 t2 then set s 
    else
      let accu1 = diff accu1 t1 in guard (slot accu1) set s;
      let accu2 = diff accu2 t2 in guard (slot accu2) set s in
  guard (slot accu1) (guard (slot accu2) (big_conj single_right right)) s

and check_arrow (left,right) s =
  let single_right (s1,s2) s =
    let accu1 = descr s1 and accu2 = neg (descr s2) in
    let single_left (t1,t2) s =
      let accu1 = diff_t accu1 t1 in guard (slot accu1) set s;
      let accu2 = cap_t  accu2 t2 in guard (slot accu2) set s
    in
    guard (slot accu1) (big_conj single_left left) s
  in
  big_conj single_right right s

and check_record (labels,(oleft,left),rights) s =
  let rec single_right (oright,right) s = 
    let next =
      (oleft && (not oright)) ||
      exists (Array.length left)
	(fun i -> trivially_disjoint left.(i) right.(i))
    in
    if next then set s
    else
      for i = 0 to Array.length left - 1 do
	let di = diff left.(i) right.(i) in guard (slot di) set s
      done
  in
  let rec start i s =
    if (i < 0) then big_conj single_right rights s
    else guard (slot left.(i)) (start (i - 1)) s
  in
  start (Array.length left - 1) s


let is_empty d =
  let s = slot d in
  List.iter 
    (fun s' -> 
       if s'.status == Maybe then s'.status <- Empty; s'.notify <- Nothing) 
    !marks;
  marks := [];
  s.status == Empty
end

let clearly_disjoint t1 t2 =
(*
  if trivially_disjoint t1 t2 then true
  else
    if ClearlyEmpty.is_empty (cap t1 t2) then
      (Printf.eprintf "!\n"; true) else false
*)
  trivially_disjoint t1 t2 || ClearlyEmpty.is_empty (cap t1 t2) 

757 758
(* TODO: need to invesigate when ClearEmpty is a good thing... *)

759 760 761 762
let memo = DescrHash.create 33000
let marks = ref [] 

let rec slot d =
763 764
  if not ((Intervals.is_empty d.ints) && 
	  (Atoms.is_empty d.atoms) &&
765 766
	  (Chars.is_empty d.chars) &&
	  (not d.absent)) then slot_not_empty 
767 768 769 770 771
  else try DescrHash.find memo d
  with Not_found ->
    let s = { status = Maybe; active = false; notify = Nothing } in
    DescrHash.add memo d s;
    (try
772
       iter_s s check_times (BoolPair.get d.times);  
773
       iter_s s check_xml (BoolPair.get d.xml); 
774
       iter_s s check_arrow (BoolPair.get d.arrow);
775 776 777 778 779 780 781 782 783
       iter_s s check_record (get_record d.record);
       if s.active then marks := s :: !marks else s.status <- Empty;
     with
	 NotEmpty -> ());
    s

and check_times (left,right) s =
  let rec aux accu1 accu2 right s = match right with
    | (t1,t2)::right ->
784 785 786
	let t1 = descr t1 and t2 = descr t2 in
	if trivially_disjoint accu1 t1 || 
	   trivially_disjoint accu2 t2 then (
787 788
	     aux accu1 accu2 right s )
	else (
789
          let accu1' = diff accu1 t1 in 
790
	  guard (slot accu1') (aux accu1' accu2 right) s;
791 792

          let accu2' = diff accu2 t2 in 
793
	  guard (slot accu2') (aux accu1 accu2' right) s  
794
	)
795 796
    | [] -> set s
  in
797
  let (accu1,accu2) = cap_product any any left in
798
  guard (slot accu1) (guard (slot accu2) (aux accu1 accu2 right)) s
799 800 801 802 803

and check_xml (left,right) s =
  let rec aux accu1 accu2 right s = match right with
    | (t1,t2)::right ->
	let t1 = descr t1 and t2 = descr t2 in
804
	if clearly_disjoint accu1 t1 || 
805 806 807 808
	   trivially_disjoint accu2 t2 then (
	     aux accu1 accu2 right s )
	else (
          let accu1' = diff accu1 t1 in 
809
	  guard (slot accu1') (aux accu1' accu2 right) s;
810 811

          let accu2' = diff accu2 t2 in 
812
	  guard (slot accu2') (aux accu1 accu2' right) s  
813 814 815 816
	)
    | [] -> set s
  in
  let (accu1,accu2) = cap_product any any_pair left in
817
  guard (slot accu1) (guard (slot accu2) (aux accu1 accu2 right)) s
818

819 820 821 822
and check_arrow (left,right) s =
  let single_right (s1,s2) s =
    let rec aux accu1 accu2 left s = match left with
      | (t1,t2)::left ->
823
          let accu1' = diff_t accu1 t1 in 
824
	  guard (slot accu1') (aux accu1' accu2 left) s;
825 826

          let accu2' = cap_t  accu2 t2 in 
827
	  guard (slot accu2') (aux accu1 accu2' left) s
828 829 830
      | [] -> set s
    in
    let accu1 = descr s1 in
831
    guard (slot accu1) (aux accu1 (neg (descr s2)) left) s
832 833
  in
  big_conj single_right right s
834

835
and check_record (labels,(oleft,left),rights) s =
836 837
  let rec aux rights s = match rights with
    | [] -> set s
838
    | (oright,right)::rights ->
839
	let next =
840
	  (oleft && (not oright)) ||
841
	  exists (Array.length left)
842
	    (fun i -> trivially_disjoint left.(i) right.(i))
843 844 845 846 847 848
	in
	if next then aux rights s
	else
	  for i = 0 to Array.length left - 1 do
	    let back = left.(i) in
	    let di = diff back right.(i) in
849 850
	    guard (slot di) (fun s ->
			left.(i) <- di;
851 852 853
			aux rights s;
			left.(i) <- back;
		     ) s
854
(* TODO: are side effects correct ? *)
855 856 857 858 859
	  done
  in
  let rec start i s =
    if (i < 0) then aux rights s
    else
860
      guard (slot left.(i)) (start (i - 1)) s
861 862 863 864
  in
  start (Array.length left - 1) s


865
(*
866
let timer_subtype = Stats.Timer.create "Types.is_empty"
867
*)
868

869
let is_empty d =
870
(*  Stats.Timer.start timer_subtype;*)
871 872
  let s = slot d in
  List.iter 
873 874
    (fun s' -> 
       if s'.status == Maybe then s'.status <- Empty; s'.notify <- Nothing) 
875 876
    !marks;
  marks := [];
877
(*  Stats.Timer.stop timer_subtype *)
878
    (s.status == Empty)
879

880
(*
881
let is_empty d =
882 883 884 885 886 887 888
(*  let b1 = ClearlyEmpty.is_empty d in
  let b2 = is_empty d in
  assert (b2 || not b1);
  Printf.eprintf "b1 = %b; b2 = %b\n" b1 b2;
  b2  *)
  if ClearlyEmpty.is_empty d then (Printf.eprintf "!\n"; true) else is_empty d
*)  
889 890 891 892 893 894 895 896 897 898 899 900 901

let non_empty d = 
  not (is_empty d)

let subtype d1 d2 =
  is_empty (diff d1 d2)

module Product =
struct
  type t = (descr * descr) list

  let other ?(kind=`Normal) d = 
    match kind with
902 903
      | `Normal -> { d with hash = 0; times = empty.times }
      | `XML -> { d with hash = 0; xml = empty.xml }
904 905 906 907 908

  let is_product ?kind d = is_empty (other ?kind d)

  let need_second = function _::_::_ -> true | _ -> false

909 910 911 912
  let normal_aux = function
    | ([] | [ _ ]) as d -> d
    | d ->

913 914 915 916 917 918 919
    let res = ref [] in

    let add (t1,t2) =
      let rec loop t1 t2 = function
	| [] -> res := (ref (t1,t2)) :: !res
	| ({contents = (d1,d2)} as r)::l ->
	    (*OPT*) 
920
(*	    if equal_descr d1 t1 then r := (d1,cup d2 t2) else*)
921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944
	      
	      let i = cap t1 d1 in
	      if is_empty i then loop t1 t2 l
	      else (
		r := (i, cup t2 d2);
		let k = diff d1 t1 in 
		if non_empty k then res := (ref (k,d2)) :: !res;
		
		let j = diff t1 d1 in 
		if non_empty j then loop j t2 l
	      )
      in
      loop t1 t2 !res
    in
    List.iter add d;
    List.map (!) !res


(* Partitioning:

(t,s) - ((t1,s1) | (t2,s2) | ... | (tn,sn))
=
(t & t1, s - s1) | ... | (t & tn, s - sn) | (t - (t1|...|tn), s)

945
*)
946
  let get_aux any_right d =
947 948
    let accu = ref [] in
    let line (left,right) =
949
      let (d1,d2) = cap_product any any_right left in
950 951 952 953 954 955 956 957 958 959 960 961 962 963 964
      if (non_empty d1) && (non_empty d2) then
	let right = List.map (fun (t1,t2) -> descr t1, descr t2) right in
	let right = normal_aux right in
	let resid1 = ref d1 in
	let () = 
	  List.iter
	    (fun (t1,t2) ->
	       let t1 = cap d1 t1 in
	       if (non_empty t1) then
		 let () = resid1 := diff !resid1 t1 in
		 let t2 = diff d2 t2 in
		 if (non_empty t2) then accu := (t1,t2) :: !accu
	    ) right in
	if non_empty !resid1 then accu := (!resid1, d2) :: !accu 
    in
965
    List.iter line (BoolPair.get d);
966
    !accu
967 968 969
(* Maybe, can improve this function with:
     (t,s) \ (t1,s1) = (t&t',s\s') | (t\t',s),
   don't call normal_aux *)
970

971

972 973
  let get ?(kind=`Normal) d = 
    match kind with
974 975
      | `Normal -> get_aux any d.times
      | `XML -> get_aux any_pair d.xml
976 977 978

  let pi1 = List.fold_left (fun acc (t1,_) -> cup acc t1) empty
  let pi2 = List.fold_left (fun acc (_,t2) -> cup acc t2) empty
979 980 981 982
  let pi2_restricted restr = 
    List.fold_left (fun acc (t1,t2) -> 
		      if is_empty (cap t1 restr) then acc
		      else cup acc t2) empty
983 984

  let restrict_1 rects pi1 =
985 986
    let aux acc (t1,t2) = 
      let t1 = cap t1 pi1 in if is_empty t1 then acc else (t1,t2)::acc in
987 988 989 990
    List.fold_left aux [] rects
  
  type normal = t

991
  module Memo = Map.Make(BoolPair)
992

993 994
  (* TODO: try with an hashtable *)
  (* Also, avoid lookup for simple products (t1,t2) *)
995
  let memo = ref Memo.empty