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     public GSS() { }
  15
  16     private Phase.Node[] reducing_list = null;
  17     public int resets = 0;
  18     public int waits = 0;
  19
  20     HashMapBag<Integer,Sequence>       inhibited       = new HashMapBag<Integer,Sequence>();
  21     HashMapBag<Integer,Sequence>       expectedInhibit = new HashMapBag<Integer,Sequence>();
  22     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  23     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  24     HashMapBag<Integer,Sequence>       lastperformed   = 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 {
  31
  32         public void invoke(State st, Forest result, Node n) {
  33             good |= next.newNode(n, result, st, false);
  34         }
  35
  36         /** the token immediately after this phase */
  37         final Tok token;
  38
  39         private final int pos;
  40
  41         boolean reducing;
  42         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  43         private IntPairMap<Forest> singularReductions;  /* ALLOC */
  44         private boolean closed;
  45         private boolean good;
  46         private Phase next = null;
  47         private Phase prev;
  48         private Input.Location location;
  49         public final Parser parser;
  50
  51         private Forest forest;
  52
  53         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Forest forest) throws ParseFailed {
  54             this.prev = prev;
  55             this.forest = forest;
  56             this.parser = parser;
  57             this.pos = previous==null ? 0 : previous.pos+1;
  58             this.token = token;
  59             this.location = location;
  60             inhibited.clear();
  61             reset();
  62         }
  63
  64         public void reset() throws ParseFailed {
  65             waiting.clear();
  66             lastperformed.clear();
  67             lastperformed.addAll(performed);
  68             performed.clear();
  69             hash = new IntPairMap<Phase.Node>();
  70             singularReductions = new IntPairMap<Forest>();
  71             expectedInhibit.clear();
  72             expectedInhibit.addAll(inhibited);
  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 : lastperformed.getAll(pos))
 109                         if (owner.hates.contains(s))
 110                             return;
 111                     for (Sequence s : performed.getAll(pos))
 112                         if (owner.hates.contains(s))
 113                             return;
 114                 }
 115                 if (inhibited.contains(pos, owner)) return;
 116                 if (owner.needs != null)
 117                     for(Sequence s : owner.needs)
 118                         if (!performed.contains(pos, s)) {
 119                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 120                             return;
 121                         }
 122                 /*
 123                 if ((owner.needed != null && owner.needed.size()>0) ||
 124                     (owner.hated != null && owner.hated.size()>0) ||
 125                     (owner.hates != null && owner.hates.size()>0))
 126                     performed.add(pos, owner);
 127                 */
 128             }
 129             if (reduction!=null) uninhibit(reduction, parent==null?0:parent.phase().pos);
 130             if (!owner.lame)
 131                 newNode(parent, pending, state, fromEmptyReduction);
 132             if (reduction != null) {
 133                 boolean redo = true;
 134                 while(redo) {
 135                     redo = false;
 136                     for(Waiting w : waiting.getAll(owner)) {
 137                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 138                             waiting.remove(owner, w);
 139                             w.perform();
 140                             redo = true;
 141                             break;
 142                         }
 143                     }
 144                 }
 145             }
 146         }
 147         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 148             p.holder.merge(pending);
 149             if (p.parents().contains(parent)) return true;
 150             p.parents().add(parent, true);
 151             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 152             return true;
 153         }
 154         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 155             do {
 156                 if (token != null && state.canShift(token)) break;
 157                 if (state.isAccepting()) break;
 158                 if (token==null) break;
 159                 if (!state.canReduce(token)) return false;
 160                 //if (count > 1) break;
 161                 //if (r.numPop == 0) break;
 162                 //r.reduce(pending, parent, null, Phase.this, null);
 163                 //return;
 164             } while(false);
 165
 166             Node n = new Node(parent, pending, state);  // ALLOC
 167             if (reducing) {
 168                 n.performEmptyReductions();
 169                 if (!fromEmptyReduction) n.performReductions(parent);
 170             }
 171             return true;
 172         }
 173
 174         public void inhibit(int p, Sequence s) {
 175             //if (inhibited.contains(p, s)) return;
 176             if (performed.contains(p, s)) throw new Reset();
 177             /*
 178             if (s.hated!=null)
 179                 for(Sequence s2 : s.hated)
 180                     uninhibit(p, s2);
 181             */
 182             if (s.needed!=null)
 183                 for(Sequence s2 : s.needed)
 184                     if (performed.contains(p, s2))
 185                         throw new Reset();
 186             if (performed.contains(p, s)) throw new Reset();
 187         }
 188
 189         public void uninhibit(Position r, int p) { uninhibit(p, r.owner()); }
 190         public void uninhibit(int p, Sequence s) {
 191             if (performed.contains(p, s)) return;
 192             performed.add(p, s);
 193             if (s.hated != null)
 194                 for(Sequence seq : s.hated)
 195                     inhibit(p, seq);
 196         }
 197
 198         /** perform all reduction operations */
 199         public void reduce() throws ParseFailed {
 200             try {
 201                 reducing = true;
 202                 if (reducing_list==null || reducing_list.length < hash.size())
 203                     reducing_list = new Phase.Node[hash.size() * 4];
 204                 hash.toArray(reducing_list);
 205                 int num = hash.size();
 206                 for(int i=0; i<num; i++) {
 207                     Node n = reducing_list[i];
 208                     n.performEmptyReductions();
 209                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 210                 }
 211                 for(int i=0; i<num; i++) {
 212                     Node n = reducing_list[i];
 213                     reducing_list[i] = null;
 214                     n.performReductions();
 215                 }
 216                 /*
 217                 if (expectedInhibit.size() > 0) {
 218                     System.out.println("\n!!!!");
 219                     for(int i : expectedInhibit)
 220                         for(Sequence es : expectedInhibit.getAll(i))
 221                             System.out.println("   " + i + ": " + es);
 222                     System.out.println("");
 223                     inhibited.removeAll(expectedInhibit);
 224                     throw new Reset();
 225                 }
 226                 */
 227                 if (reset) {
 228                     reset = false;
 229                     resets++;
 230                     throw new Reset();
 231                 }
 232             } catch (Reset r) {
 233                 reset();
 234                 reduce();
 235             }
 236             count = 0;
 237         }
 238
 239         private boolean reset = false;
 240         class Reset extends RuntimeException { }
 241
 242         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 243         public void shift(Phase next, Forest result) throws ParseFailed {
 244             // this massively improves GC performance
 245             if (prev!=null) {
 246                 prev.hash = null;
 247                 prev.singularReductions = null;
 248             }
 249             this.next = next;
 250             closed = true;
 251             Forest res = null;
 252             boolean ok = false;
 253             for(Phase.Node n : hash.values()) {
 254                 if (token == null && n.state.isAccepting()) {
 255                     if (finalResult==null) finalResult = new Forest.Ref();
 256                     finalResult.merge(n.holder);
 257                 }
 258                 if (token == null) continue;
 259                 n.state.invokeShifts(token, this, result, n);
 260             }
 261
 262             if (!good && token!=null)
 263                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 264                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 265                                                         "\' encountered at "+
 266                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 267                                         getLocation());
 268             if (token==null && finalResult==null)
 269                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 270                                         getLocation());
 271         }
 272
 273
 274         class Waiting {
 275             Node parent;
 276             Forest pending;
 277             State state;
 278             boolean fromEmptyReduction;
 279             Position reduction;
 280             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 281                 waits++;
 282                 this.parent = parent;
 283                 this.pending = pending;
 284                 this.state = state;
 285                 this.fromEmptyReduction = fromEmptyReduction;
 286                 this.reduction = reduction;
 287             }
 288             public void perform() {
 289                 //System.out.println("performing: " + reduction.position);
 290                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 291             }
 292         }
 293
 294         // Node /////////////////////////////////////////////////////////////////////////////////
 295
 296         /** a node in the GSS */
 297         final class Node extends FastSet<Node> implements Invokable<Position, Node, Node>, IntegerMappable {
 298
 299             private Forest.Ref holder = null;
 300             private boolean allqueued = false;
 301
 302             /** what state this node is in */
 303             public final Parser.Table<Tok>.State<Tok> state;
 304
 305             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 306             public  Phase phase() { return Phase.this; }
 307             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 308             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 309             public  FastSet<Node> parents() { return this; }
 310
 311             public void performReductions() {
 312                 if (allqueued) return;
 313                 allqueued = true;
 314                 state.invokeReductions(token, this, this, null);
 315             }
 316
 317             public void performReductions(Node n2) {
 318                 if (!allqueued) performReductions();
 319                 else            state.invokeReductions(token, this, this, n2);
 320             }
 321
 322             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 323             public final void invoke(Position r, Node n, Node n2) {
 324                 if (n==null || n2==null || r.pos==0) {
 325                     if (r.pos==0) {
 326                         if (n==null) n = this;
 327                         else return;
 328                     }
 329                     if (n==null) return;
 330                     Forest[] holder = new Forest[r.pos];
 331                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 332                     else                   n.reduce(r, r.pos-1, n.phase(), holder);
 333                 } else {
 334                     Forest[] holder = new Forest[r.pos];
 335                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 336                     int pos = r.pos-1;
 337                     n.reduce(r, pos, n.phase(), holder, n2);
 338                 }
 339             }
 340
 341             public void reduce(Position r, int pos, Phase target, Forest[] holder) { reduce(r, pos, target, holder, null); }
 342             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 343                 Forest old = holder[pos];
 344                 holder[pos] = this.pending();
 345                 if (pos==0) {
 346                     System.arraycopy(holder, 0, r.holder, 0, holder.length);
 347                     for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 348                     Forest rex = null;
 349
 350                     // FIXME: I'm unsure about this -- basically we want to deal with the case where
 351                     //        there are two nodes, each of whose Ref points to the same Forest instance.
 352                     //        Some node in the next phase has both of these as parents.  This might happen
 353                     //        since the same reduction can appear in more than one state.
 354                     if (r.pos==1)  rex = singularReductions.get(this.pending(), r);
 355                     if (rex==null) {
 356                         rex = r.rewrite(phase().getLocation());
 357                         if (r.pos==1) singularReductions.put(this.pending(), r, rex);
 358                     }
 359                     if (only != null)  only.finish(r, rex, target, holder);
 360                     else               for(Node child : this.parents()) child.finish(r, rex, target, holder);
 361                 } else {
 362                     if (only != null)  only.reduce(r, pos-1, target, holder);
 363                     else               for(Node child : this.parents()) child.reduce(r, pos-1, target, holder);
 364                 }
 365                 holder[pos] = old;
 366             }
 367
 368             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 369                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 370                 if (result==null) throw new Error();
 371                 if (state0!=null)
 372                     target.newNode(this, result, state0, r.pos<=0, r);
 373             }
 374
 375             private Node(Node parent, Forest pending, State state) {
 376                 this.state = state;
 377                 this.holder().merge(pending);
 378                 Phase start = parent==null ? null : parent.phase();
 379                 if (parent != null) parents().add(parent, true);
 380                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 381                 Phase.this.hash.put(state, start, this);
 382             }
 383             public int toInt() { return idx; }
 384             private final int idx = node_idx++;
 385         }
 386         private int node_idx = 0;
 387
 388         public int toInt() { return pos+1; }
 389         public int size() { return hash==null ? 0 : hash.size(); }
 390     }
 391
 392 }