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
  25     /** FIXME */
  26     public  Forest.Ref finalResult;
  27
  28     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  29     class Phase<Tok> implements Invokable<State, Forest, Phase<Tok>.Node>, IntegerMappable {
  30
  31         public void invoke(State st, Forest result, Node n) {
  32             good |= next.newNode(n, result, st, false);
  33         }
  34
  35         /** the token immediately after this phase */
  36         final Tok token;
  37
  38         private final int pos;
  39
  40         boolean reducing;
  41         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  42         private IntPairMap<Forest> singularReductions;  /* ALLOC */
  43         private boolean closed;
  44         private boolean good;
  45         private Phase next = null;
  46         private Phase prev;
  47         private Input.Location location;
  48         public final Parser parser;
  49
  50         private Forest forest;
  51
  52         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Forest forest) throws ParseFailed {
  53             this.prev = prev;
  54             this.forest = forest;
  55             this.parser = parser;
  56             this.pos = previous==null ? 0 : previous.pos+1;
  57             this.token = token;
  58             this.location = location;
  59             inhibited.clear();
  60             reset();
  61         }
  62
  63         public void reset() throws ParseFailed {
  64             waiting.clear();
  65             performed.clear();
  66             hash = new IntPairMap<Phase.Node>();
  67             singularReductions = new IntPairMap<Forest>();
  68             expectedInhibit.clear();
  69             expectedInhibit.addAll(inhibited);
  70             reset = false;
  71             good = false;
  72             closed = false;
  73             reducing = false;
  74             finalResult = null;
  75             if (prev != null) prev.shift(this, forest);
  76         }
  77
  78
  79         public boolean isDone() throws ParseFailed {
  80             if (token != null) return false;
  81             if (token==null && finalResult==null)
  82                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  83             return true;
  84         }
  85
  86         public Input.Location getLocation() { return location; }
  87
  88         /** add a new node (merging with existing nodes if possible)
  89          *  @param parent             the parent of the new node
  90          *  @param result             the SPPF result corresponding to the new node
  91          *  @param state              the state that the new node is in
  92          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
  93          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
  94          */
  95         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
  96             Node p = hash.get(state, parent==null?null:parent.phase());
  97             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
  98             else            return newNode3(parent, pending, state, fromEmptyReduction);
  99         }
 100         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 101             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 102             Sequence owner = reduction==null ? null : reduction.owner();
 103             if (reduction!=null) {
 104                 if (inhibited.contains(pos, owner)) return;
 105                 if (owner.needs != null)
 106                     for(Sequence s : owner.needs)
 107                         if (!performed.contains(pos, s)) {
 108                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 109                             return;
 110                         }
 111                 if ((owner.needed != null && owner.needed.size()>0) ||
 112                     (owner.hated != null && owner.hated.size()>0) ||
 113                     (owner.hates != null && owner.hates.size()>0))
 114                     performed.add(pos, owner);
 115             }
 116             if (!owner.lame)
 117                 newNode(parent, pending, state, fromEmptyReduction);
 118             if (reduction!=null) uninhibit(reduction, parent==null?0:parent.phase().pos);
 119             if (reduction != null) {
 120                 boolean redo = true;
 121                 while(redo) {
 122                     redo = false;
 123                     for(Waiting w : waiting.getAll(owner)) {
 124                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 125                             waiting.remove(owner, w);
 126                             w.perform();
 127                             redo = true;
 128                             break;
 129                         }
 130                     }
 131                 }
 132             }
 133         }
 134         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 135             p.holder.merge(pending);
 136             if (p.parents().contains(parent)) return true;
 137             p.parents().add(parent, true);
 138             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 139             return true;
 140         }
 141         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 142             do {
 143                 if (token != null && state.canShift(token)) break;
 144                 if (state.isAccepting()) break;
 145                 if (token==null) break;
 146                 if (!state.canReduce(token)) return false;
 147                 //if (count > 1) break;
 148                 //if (r.numPop == 0) break;
 149                 //r.reduce(pending, parent, null, Phase.this, null);
 150                 //return;
 151             } while(false);
 152
 153             Node n = new Node(parent, pending, state);  // ALLOC
 154             if (reducing) {
 155                 n.performEmptyReductions();
 156                 if (!fromEmptyReduction) n.performReductions(parent);
 157             }
 158             return true;
 159         }
 160
 161         public void inhibit(int p, Sequence s) {
 162             if (s.hated!=null)
 163                 for(Sequence s2 : s.hated)
 164                     inhibited.remove(p, s2);
 165         }
 166
 167         public void uninhibit(Position r, int p) {
 168             if (r.owner().hated == null) return;
 169             // remember that dead states are still allowed to shift -- just not allowed to reduce
 170             boolean reset = false;
 171             for(Sequence seq : r.owner().hated) {
 172                 if (performed.contains(p,seq)) {
 173                     inhibit(p, seq);
 174                     //System.out.println("\nresetting due to " + r.owner() + " killing " + seq);
 175                     //inhibited.clear();
 176                     inhibited.add(p, seq);
 177                     //inhibited = new HashMapBag<Integer,Sequence>();
 178                     reset = true;
 179                     resets++;
 180                     throw new Reset();
 181                 }
 182                 inhibited.add(p, seq);
 183                 expectedInhibit.remove(p, seq);
 184             }
 185         }
 186
 187         /** perform all reduction operations */
 188         public void reduce() throws ParseFailed{
 189             try {
 190                 reducing = true;
 191                 if (reducing_list==null || reducing_list.length < hash.size())
 192                     reducing_list = new Phase.Node[hash.size() * 4];
 193                 hash.toArray(reducing_list);
 194                 int num = hash.size();
 195                 for(int i=0; i<num; i++) {
 196                     Node n = reducing_list[i];
 197                     n.performEmptyReductions();
 198                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 199                 }
 200                 for(int i=0; i<num; i++) {
 201                     Node n = reducing_list[i];
 202                     reducing_list[i] = null;
 203                     n.performReductions();
 204                 }
 205                 if (expectedInhibit.size() > 0) {
 206                     inhibited.removeAll(expectedInhibit);
 207                     System.out.println("\n!!!!\n");
 208                     throw new Reset();
 209                 }
 210             } catch (Reset r) {
 211                 reset();
 212                 reduce();
 213             }
 214             count = 0;
 215         }
 216
 217         private boolean reset = false;
 218         class Reset extends RuntimeException { }
 219
 220         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 221         public void shift(Phase next, Forest result) throws ParseFailed {
 222             // this massively improves GC performance
 223             if (prev!=null) {
 224                 prev.hash = null;
 225                 prev.singularReductions = null;
 226             }
 227             this.next = next;
 228             closed = true;
 229             Forest res = null;
 230             boolean ok = false;
 231             for(Phase.Node n : hash.values()) {
 232                 if (token == null && n.state.isAccepting()) {
 233                     if (finalResult==null) finalResult = new Forest.Ref();
 234                     finalResult.merge(n.holder);
 235                 }
 236                 if (token == null) continue;
 237                 n.state.invokeShifts(token, this, result, n);
 238             }
 239
 240             if (!good && token!=null)
 241                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 242                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 243                                                         "\' encountered at "+
 244                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 245                                         getLocation());
 246             if (token==null && finalResult==null)
 247                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 248                                         getLocation());
 249         }
 250
 251
 252         class Waiting {
 253             Node parent;
 254             Forest pending;
 255             State state;
 256             boolean fromEmptyReduction;
 257             Position reduction;
 258             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 259                 waits++;
 260                 this.parent = parent;
 261                 this.pending = pending;
 262                 this.state = state;
 263                 this.fromEmptyReduction = fromEmptyReduction;
 264                 this.reduction = reduction;
 265             }
 266             public void perform() {
 267                 //System.out.println("performing: " + reduction.position);
 268                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 269             }
 270         }
 271
 272         // Node /////////////////////////////////////////////////////////////////////////////////
 273
 274         /** a node in the GSS */
 275         final class Node extends FastSet<Node> implements Invokable<Position, Node, Node>, IntegerMappable {
 276
 277             private Forest.Ref holder = null;
 278             private boolean allqueued = false;
 279
 280             /** what state this node is in */
 281             public final Parser.Table<Tok>.State<Tok> state;
 282
 283             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 284             public  Phase phase() { return Phase.this; }
 285             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 286             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 287             public  FastSet<Node> parents() { return this; }
 288
 289             public void performReductions() {
 290                 if (allqueued) return;
 291                 allqueued = true;
 292                 state.invokeReductions(token, this, this, null);
 293             }
 294
 295             public void performReductions(Node n2) {
 296                 if (!allqueued) performReductions();
 297                 else            state.invokeReductions(token, this, this, n2);
 298             }
 299
 300             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 301             public final void invoke(Position r, Node n, Node n2) {
 302                 if (n==null || n2==null || r.pos==0) {
 303                     if (r.pos==0) {
 304                         if (n==null) n = this;
 305                         else return;
 306                     }
 307                     if (n==null) return;
 308                     Forest[] holder = new Forest[r.pos];
 309                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 310                     else                   n.reduce(r, r.pos-1, n.phase(), holder);
 311                 } else {
 312                     Forest[] holder = new Forest[r.pos];
 313                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 314                     int pos = r.pos-1;
 315                     n.reduce(r, pos, n.phase(), holder, n2);
 316                 }
 317             }
 318
 319             public void reduce(Position r, int pos, Phase target, Forest[] holder) { reduce(r, pos, target, holder, null); }
 320             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 321                 Forest old = holder[pos];
 322                 holder[pos] = this.pending();
 323                 if (pos==0) {
 324                     System.arraycopy(holder, 0, r.holder, 0, holder.length);
 325                     for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 326                     Forest rex = null;
 327
 328                     // FIXME: I'm unsure about this -- basically we want to deal with the case where
 329                     //        there are two nodes, each of whose Ref points to the same Forest instance.
 330                     //        Some node in the next phase has both of these as parents.  This might happen
 331                     //        since the same reduction can appear in more than one state.
 332                     if (r.pos==1)  rex = singularReductions.get(this.pending(), r);
 333                     if (rex==null) {
 334                         rex = r.rewrite(phase().getLocation());
 335                         if (r.pos==1) singularReductions.put(this.pending(), r, rex);
 336                     }
 337                     if (only != null)  only.finish(r, rex, target, holder);
 338                     else               for(Node child : this.parents()) child.finish(r, rex, target, holder);
 339                 } else {
 340                     if (only != null)  only.reduce(r, pos-1, target, holder);
 341                     else               for(Node child : this.parents()) child.reduce(r, pos-1, target, holder);
 342                 }
 343                 holder[pos] = old;
 344             }
 345
 346             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 347                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 348                 if (result==null) throw new Error();
 349                 if (state0!=null)
 350                     target.newNode(this, result, state0, r.pos<=0, r);
 351             }
 352
 353             private Node(Node parent, Forest pending, State state) {
 354                 this.state = state;
 355                 this.holder().merge(pending);
 356                 Phase start = parent==null ? null : parent.phase();
 357                 if (parent != null) parents().add(parent, true);
 358                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 359                 Phase.this.hash.put(state, start, this);
 360             }
 361             public int toInt() { return idx; }
 362             private final int idx = node_idx++;
 363         }
 364         private int node_idx = 0;
 365
 366         public int toInt() { return pos+1; }
 367         public int size() { return hash==null ? 0 : hash.size(); }
 368     }
 369
 370 }