src/edu/berkeley/sbp/GSS.java

   1 package edu.berkeley.sbp;
   2 import edu.berkeley.sbp.*;
   3 import edu.berkeley.sbp.util.*;
   4 import edu.berkeley.sbp.Parser.Table.*;
   5 import edu.berkeley.sbp.Sequence.Position;
   6 import java.io.*;
   7 import java.util.*;
   8 import java.lang.reflect.*;
   9
  10 /** implements Tomita's Graph Structured Stack */
  11 class GSS {
  12
  13     public static int count = 0;
  14
  15     public GSS() { }
  16
  17     private Phase.Node[] reducing_list = null;
  18     public int resets = 0;
  19     public int waits = 0;
  20
  21     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  22     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  23     HashMapBag<Integer,Sequence>       lastperformed   = new HashMapBag<Integer,Sequence>();
  24     HashMapBag<Integer,Sequence>       expected        = new HashMapBag<Integer,Sequence>();
  25
  26     /** FIXME */
  27     public  Forest.Ref finalResult;
  28
  29     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  30     class Phase<Tok> implements Invokable<State, Forest, Phase<Tok>.Node>, IntegerMappable, GraphViz.ToGraphViz, Iterable<Phase.Node> {
  31
  32         public Iterator<Phase.Node> iterator() { return hash.iterator(); }
  33         public void invoke(State st, Forest result, Node n) {
  34             good |= next.newNode(n, result, st, false);
  35         }
  36
  37         /** the token immediately after this phase */
  38         final Tok token;
  39
  40         private final int pos;
  41
  42         boolean reducing;
  43         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  44         private IntPairMap<Forest> singularReductions;  /* ALLOC */
  45         private boolean closed;
  46         private boolean good;
  47         private Phase next = null;
  48         private Phase prev;
  49         private Input.Location location;
  50         public final Parser parser;
  51
  52         private Forest forest;
  53
  54         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Forest forest) throws ParseFailed {
  55             this.prev = prev;
  56             this.forest = forest;
  57             this.parser = parser;
  58             this.pos = previous==null ? 0 : previous.pos+1;
  59             this.token = token;
  60             this.location = location;
  61             performed.clear();
  62             reset();
  63         }
  64
  65         public void reset() throws ParseFailed {
  66             waiting.clear();
  67             expected.clear();
  68             lastperformed.clear();
  69             lastperformed.addAll(performed);
  70             performed.clear();
  71             hash = new IntPairMap<Phase.Node>();
  72             singularReductions = new IntPairMap<Forest>();
  73             reset = false;
  74             good = false;
  75             closed = false;
  76             reducing = false;
  77             finalResult = null;
  78             if (prev != null) prev.shift(this, forest);
  79         }
  80
  81
  82         public boolean isDone() throws ParseFailed {
  83             if (token != null) return false;
  84             if (token==null && finalResult==null)
  85                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  86             return true;
  87         }
  88
  89         public Input.Location getLocation() { return location; }
  90
  91         /** add a new node (merging with existing nodes if possible)
  92          *  @param parent             the parent of the new node
  93          *  @param result             the SPPF result corresponding to the new node
  94          *  @param state              the state that the new node is in
  95          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
  96          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
  97          */
  98         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
  99             Node p = hash.get(state, parent==null?null:parent.phase());
 100             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 101             else            return newNode3(parent, pending, state, fromEmptyReduction);
 102         }
 103         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 104             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 105             Sequence owner = reduction==null ? null : reduction.owner();
 106             if (reduction!=null) {
 107                 if (owner.hates!=null) {
 108                     for (Sequence s : performed.getAll(pos))
 109                         if (owner.hates.contains(s))
 110                             return;
 111                     for (Sequence s : lastperformed.getAll(pos))
 112                         if (owner.hates.contains(s)) {
 113                             //System.out.println("now expecting ["+pos+"] => " + s);
 114                             expected.add(pos, s);
 115                             return;
 116                         }
 117                 }
 118                 if (owner.needs != null)
 119                     for(Sequence s : owner.needs)
 120                         if (!performed.contains(pos, s)) {
 121                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 122                             return;
 123                         }
 124                 if (!performed.contains(pos, owner)) {
 125                     performed.add(pos, owner);
 126                     if (owner.hated != null)
 127                         for(Sequence seq : owner.hated)
 128                             if (performed.contains(pos, seq)) {
 129                                 performed.remove(pos, seq);
 130                                 reset = true;
 131                             }
 132                 }
 133             }
 134             if (!owner.lame)
 135                 newNode(parent, pending, state, fromEmptyReduction);
 136             if (reduction != null) {
 137                 boolean redo = true;
 138                 while(redo) {
 139                     redo = false;
 140                     for(Waiting w : waiting.getAll(owner)) {
 141                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 142                             waiting.remove(owner, w);
 143                             w.perform();
 144                             redo = true;
 145                             break;
 146                         }
 147                     }
 148                 }
 149             }
 150         }
 151         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 152             //if (p.parents().contains(parent)) return true;
 153             p.merge(parent, pending);
 154             p.parents().add(parent, true);
 155             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 156             return true;
 157         }
 158         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 159             do {
 160                 if (token != null && state.canShift(token)) break;
 161                 if (state.isAccepting()) break;
 162                 if (token==null) break;
 163                 if (!state.canReduce(token)) return false;
 164                 //if (count > 1) break;
 165                 //if (r.numPop == 0) break;
 166                 //r.reduce(pending, parent, null, Phase.this, null);
 167                 //return;
 168             } while(false);
 169
 170             Node n = new Node(parent, pending, state);  // ALLOC
 171             if (reducing) {
 172                 n.performEmptyReductions();
 173                 if (!fromEmptyReduction) n.performReductions(parent);
 174             }
 175             return true;
 176         }
 177
 178         /** perform all reduction operations */
 179         public void reduce() throws ParseFailed {
 180             try {
 181                 reducing = true;
 182                 if (reducing_list==null || reducing_list.length < hash.size())
 183                     reducing_list = new Phase.Node[hash.size() * 4];
 184                 hash.toArray(reducing_list);
 185                 int num = hash.size();
 186                 for(int i=0; i<num; i++) {
 187                     Node n = reducing_list[i];
 188                     n.performEmptyReductions();
 189                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 190                 }
 191                 for(int i=0; i<num; i++) {
 192                     Node n = reducing_list[i];
 193                     reducing_list[i] = null;
 194                     n.performReductions();
 195                 }
 196                 if (reset) {
 197                     reset = false;
 198                     resets++;
 199                     throw new Reset();
 200                 }
 201                 for(int i : expected)
 202                     for(Sequence s : expected.getAll(i))
 203                         if (!performed.contains(i, s)) {
 204                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 205                             resets++;
 206                             throw new Reset();
 207                         }
 208             } catch (Reset r) {
 209                 reset();
 210                 reduce();
 211             }
 212             count = 0;
 213         }
 214
 215         private boolean reset = false;
 216         class Reset extends RuntimeException { }
 217
 218         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 219         public void shift(Phase next, Forest result) throws ParseFailed {
 220             // this massively improves GC performance
 221             if (prev!=null && parser.helpgc) {
 222                 prev.hash = null;
 223                 prev.singularReductions = null;
 224             }
 225             this.next = next;
 226             closed = true;
 227             Forest res = null;
 228             boolean ok = false;
 229             for(Phase.Node n : hash.values()) {
 230                 if (token == null && n.state.isAccepting()) {
 231                     if (finalResult==null) finalResult = new Forest.Ref();
 232                     for(Object f : n.results())
 233                         finalResult.merge((Forest)f);
 234                 }
 235                 if (token == null) continue;
 236                 n.state.invokeShifts(token, this, result, n);
 237             }
 238
 239             if (!good && token!=null)
 240                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 241                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 242                                                         "\' encountered at "+
 243                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 244                                         getLocation());
 245             if (token==null && finalResult==null)
 246                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 247                                         getLocation());
 248         }
 249
 250
 251         class Waiting {
 252             Node parent;
 253             Forest pending;
 254             State state;
 255             boolean fromEmptyReduction;
 256             Position reduction;
 257             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 258                 waits++;
 259                 this.parent = parent;
 260                 this.pending = pending;
 261                 this.state = state;
 262                 this.fromEmptyReduction = fromEmptyReduction;
 263                 this.reduction = reduction;
 264             }
 265             public void perform() {
 266                 //System.out.println("performing: " + reduction.position);
 267                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 268             }
 269         }
 270
 271         // Node /////////////////////////////////////////////////////////////////////////////////
 272
 273         /** a node in the GSS */
 274         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 275             public FastSet<Node> set = new FastSet<Node>();
 276
 277         public GraphViz.Node toGraphViz(GraphViz gv) {
 278             if (gv.hasNode(this)) return gv.createNode(this);
 279             GraphViz.Node n = gv.createNode(this);
 280             n.label = ""+state.toStringx();
 281             n.shape = "rectangle";
 282             n.fill = "green";
 283             //GraphViz.Node f = pending().toGraphViz(gv);
 284             //n.add(f);
 285             for(Forest result : results()) n.edge(result, "");
 286             for(Node parent : parents()) n.edge(parent, "");
 287             ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 288             return n;
 289         }
 290         public boolean isTransparent() { return false; }
 291         public boolean isHidden() { return false; }
 292
 293
 294             //private Forest.Ref holder = new Forest.Ref();
 295             private boolean allqueued = false;
 296
 297             /** what state this node is in */
 298             public final Parser.Table<Tok>.State<Tok> state;
 299
 300             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 301             public  Phase phase() { return Phase.this; }
 302             //private HashMap<Node,Forest> resultMap = new HashMap<Node,Forest>();
 303
 304             private HashSet<Forest.Ref> resultMap = new HashSet<Forest.Ref>();
 305             public void merge(Node parent, Forest result) {
 306                 for(Forest.Ref f : results()) {
 307                     if (f.parents.contains(parent) && f.parents.size()==1) {
 308                         f.merge(result);
 309                         return;
 310                     }
 311                 }
 312                 Forest.Ref f = new Forest.Ref();
 313                 f.parents.add(parent);
 314                 f.merge(result);
 315                 resultMap.add(f);
 316                 set.add(parent, true);
 317                 /*
 318                 Forest.Ref f = (Forest.Ref)resultMap.get(parent);
 319                 if (f==null) { f = new Forest.Ref(); resultMap.put(parent, f); }
 320                 f.merge(result);
 321                 set.add(parent, true);
 322                 */
 323             }
 324             public Iterable<Forest.Ref> results() { return resultMap; }
 325             //private Forest pending(Node n) {
 326                 //return !Phase.this.closed ? holder : holder.resolve();
 327                 /*
 328                 for(Forest f : resultMap)
 329                     if (resultMap.contains(f, n))
 330                         return f;
 331                 return null;
 332                 */
 333             /*
 334                 return resultMap.get(n);
 335             }
 336             */
 337             public  FastSet<Node> parents() { return set; }
 338
 339             public void performReductions() {
 340                 if (allqueued) return;
 341                 allqueued = true;
 342                 state.invokeReductions(token, this, this, null);
 343             }
 344
 345             public void performReductions(Node n2) {
 346                 if (!allqueued) performReductions();
 347                 else            state.invokeReductions(token, this, this, n2);
 348             }
 349
 350             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 351             public final void invoke(Position r, Node n, Node n2) {
 352                 //if (r.owner().lame) return;
 353                 if (n==null || n2==null || r.pos==0) {
 354                     if (r.pos==0) {
 355                         if (n==null) n = this;
 356                         else return;
 357                     }
 358                     if (n==null) return;
 359                     Forest[] holder = new Forest[r.pos];
 360                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 361                     else          n.reduce(r, r.pos-1,  n.phase(), holder, null, null);
 362                 } else {
 363                     Forest[] holder = new Forest[r.pos];
 364                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 365                     int pos = r.pos-1;
 366                     n.reduce(r, pos, n.phase(), holder, n2, null);
 367                 }
 368             }
 369
 370             /*
 371             public void reduce(Position r, int pos, Phase target, Forest[] holder) {
 372                 reduce(r, pos, target, holder, null); }
 373             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 374                 reduce(r, pos, target, holder, only, this.pending());
 375             }
 376             */
 377             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only, Forest pending) {
 378                 Forest old = holder[pos];
 379                 holder[pos] = pending;
 380                 if (pos==0) {
 381
 382                     // FIXME: I'm unsure about this -- basically we want to deal with the case where
 383                     //        there are two nodes, each of whose Ref points to the same Forest instance.
 384                     //        Some node in the next phase has both of these as parents.  This might happen
 385                     //        since the same reduction can appear in more than one state.
 386
 387                     if (only != null)  {
 388                         for(Forest result : results())
 389                             for(Node child : ((Forest.Ref<?>)result).parents) {
 390                                 if (child!=only) continue;
 391                                 pending = holder[pos] = result;
 392                                 System.arraycopy(holder, 0, r.holder, 0, holder.length);
 393                                 for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 394                                 Forest rex = null;
 395                                 if (r.pos==1)  rex = singularReductions.get(pending, r);
 396                                 if (rex==null) {
 397                                     rex = r.rewrite(phase().getLocation());
 398                                     if (r.pos==1) singularReductions.put(pending, r, rex);
 399                                 }
 400                                 only.finish(r, rex, target, holder);
 401                             }
 402                     } else {
 403                         for(Forest result : results()) {
 404                             pending = holder[pos] = result;
 405                             System.arraycopy(holder, 0, r.holder, 0, holder.length);
 406                             for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 407                             Forest rex = null;
 408                             if (rex==null && r.pos==1)  rex = singularReductions.get(pending, r);
 409                             if (rex==null) {
 410                                 rex = r.rewrite(phase().getLocation());
 411                                 if (r.pos==1) singularReductions.put(pending, r, rex);
 412                             }
 413                             for(Node child : ((Forest.Ref<?>)result).parents)
 414                                 child.finish(r, rex, target, holder);
 415                         }
 416                     }
 417                 } else {
 418                     if (only != null)  {
 419                         for(Forest result : results())
 420                             for(Node child : ((Forest.Ref<?>)result).parents) {
 421                                 if (child!=only) continue;
 422                                 holder[pos] = result;
 423                                 only.reduce(r, pos-1, target, holder, null, null);
 424                             }
 425                     } else {
 426                         for(Forest result : results())
 427                             for(Node child : ((Forest.Ref<?>)result).parents) {
 428                                 holder[pos] = result;
 429                                 child.reduce(r, pos-1, target, holder, null, null);
 430                             }
 431                     }
 432                 }
 433                 holder[pos] = old;
 434             }
 435
 436             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 437                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 438                 if (result==null) throw new Error();
 439                 if (state0!=null)
 440                     target.newNode(this, result, state0, r.pos<=0, r);
 441             }
 442
 443             private Node(Node parent, Forest pending, State state) {
 444                 this.state = state;
 445                 this.merge(parent, pending);
 446                 Phase start = parent==null ? null : parent.phase();
 447                 if (parent != null) parents().add(parent, true);
 448                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 449                 Phase.this.hash.put(state, start, this);
 450             }
 451             public int toInt() { return idx; }
 452             private final int idx = node_idx++;
 453         }
 454         private int node_idx = 0;
 455
 456         public int toInt() { return pos+1; }
 457         public int size() { return hash==null ? 0 : hash.size(); }
 458
 459         // GraphViz //////////////////////////////////////////////////////////////////////////////
 460
 461         public GraphViz.Node toGraphViz(GraphViz gv) {
 462             if (gv.hasNode(this)) return gv.createNode(this);
 463             GraphViz.Group g = gv.createGroup(this);
 464             g.label = "Phase " + pos;
 465             g.color = "gray";
 466             g.cluster = true;
 467             return g;
 468         }
 469         public boolean isTransparent() { return false; }
 470         public boolean isHidden() { return false; }
 471
 472     }
 473 }