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 (inhibited.contains(p, s)) return;
 163             inhibited.add(p, s);
 164             if (s.hated!=null)
 165                 for(Sequence s2 : s.hated)
 166                     uninhibit(p, s2);
 167             if (s.needed!=null)
 168                 for(Sequence s2 : s.needed)
 169                     if (performed.contains(p, s2))
 170                         throw new Reset();
 171             if (performed.contains(p, s)) throw new Reset();
 172         }
 173
 174         public void uninhibit(Position r, int p) { uninhibit(p, r.owner()); }
 175         public void uninhibit(int p, Sequence s) {
 176             if (s.hated != null)
 177                 for(Sequence seq : s.hated)
 178                     inhibit(p, seq);
 179         }
 180
 181         /** perform all reduction operations */
 182         public void reduce() throws ParseFailed {
 183             try {
 184                 reducing = true;
 185                 if (reducing_list==null || reducing_list.length < hash.size())
 186                     reducing_list = new Phase.Node[hash.size() * 4];
 187                 hash.toArray(reducing_list);
 188                 int num = hash.size();
 189                 for(int i=0; i<num; i++) {
 190                     Node n = reducing_list[i];
 191                     n.performEmptyReductions();
 192                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 193                 }
 194                 for(int i=0; i<num; i++) {
 195                     Node n = reducing_list[i];
 196                     reducing_list[i] = null;
 197                     n.performReductions();
 198                 }
 199                 /*
 200                 if (expectedInhibit.size() > 0) {
 201                     inhibited.removeAll(expectedInhibit);
 202                     System.out.println("\n!!!!\n");
 203                     throw new Reset();
 204                 }
 205                 */
 206                 if (reset) {
 207                     reset = false;
 208                     resets++;
 209                     throw new Reset();
 210                 }
 211             } catch (Reset r) {
 212                 reset();
 213                 reduce();
 214             }
 215             count = 0;
 216         }
 217
 218         private boolean reset = false;
 219         class Reset extends RuntimeException { }
 220
 221         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 222         public void shift(Phase next, Forest result) throws ParseFailed {
 223             // this massively improves GC performance
 224             if (prev!=null) {
 225                 prev.hash = null;
 226                 prev.singularReductions = null;
 227             }
 228             this.next = next;
 229             closed = true;
 230             Forest res = null;
 231             boolean ok = false;
 232             for(Phase.Node n : hash.values()) {
 233                 if (token == null && n.state.isAccepting()) {
 234                     if (finalResult==null) finalResult = new Forest.Ref();
 235                     finalResult.merge(n.holder);
 236                 }
 237                 if (token == null) continue;
 238                 n.state.invokeShifts(token, this, result, n);
 239             }
 240
 241             if (!good && token!=null)
 242                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 243                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 244                                                         "\' encountered at "+
 245                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 246                                         getLocation());
 247             if (token==null && finalResult==null)
 248                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 249                                         getLocation());
 250         }
 251
 252
 253         class Waiting {
 254             Node parent;
 255             Forest pending;
 256             State state;
 257             boolean fromEmptyReduction;
 258             Position reduction;
 259             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 260                 waits++;
 261                 this.parent = parent;
 262                 this.pending = pending;
 263                 this.state = state;
 264                 this.fromEmptyReduction = fromEmptyReduction;
 265                 this.reduction = reduction;
 266             }
 267             public void perform() {
 268                 //System.out.println("performing: " + reduction.position);
 269                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 270             }
 271         }
 272
 273         // Node /////////////////////////////////////////////////////////////////////////////////
 274
 275         /** a node in the GSS */
 276         final class Node extends FastSet<Node> implements Invokable<Position, Node, Node>, IntegerMappable {
 277
 278             private Forest.Ref holder = null;
 279             private boolean allqueued = false;
 280
 281             /** what state this node is in */
 282             public final Parser.Table<Tok>.State<Tok> state;
 283
 284             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 285             public  Phase phase() { return Phase.this; }
 286             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 287             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 288             public  FastSet<Node> parents() { return this; }
 289
 290             public void performReductions() {
 291                 if (allqueued) return;
 292                 allqueued = true;
 293                 state.invokeReductions(token, this, this, null);
 294             }
 295
 296             public void performReductions(Node n2) {
 297                 if (!allqueued) performReductions();
 298                 else            state.invokeReductions(token, this, this, n2);
 299             }
 300
 301             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 302             public final void invoke(Position r, Node n, Node n2) {
 303                 if (n==null || n2==null || r.pos==0) {
 304                     if (r.pos==0) {
 305                         if (n==null) n = this;
 306                         else return;
 307                     }
 308                     if (n==null) return;
 309                     Forest[] holder = new Forest[r.pos];
 310                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 311                     else                   n.reduce(r, r.pos-1, n.phase(), holder);
 312                 } else {
 313                     Forest[] holder = new Forest[r.pos];
 314                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 315                     int pos = r.pos-1;
 316                     n.reduce(r, pos, n.phase(), holder, n2);
 317                 }
 318             }
 319
 320             public void reduce(Position r, int pos, Phase target, Forest[] holder) { reduce(r, pos, target, holder, null); }
 321             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 322                 Forest old = holder[pos];
 323                 holder[pos] = this.pending();
 324                 if (pos==0) {
 325                     System.arraycopy(holder, 0, r.holder, 0, holder.length);
 326                     for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 327                     Forest rex = null;
 328
 329                     // FIXME: I'm unsure about this -- basically we want to deal with the case where
 330                     //        there are two nodes, each of whose Ref points to the same Forest instance.
 331                     //        Some node in the next phase has both of these as parents.  This might happen
 332                     //        since the same reduction can appear in more than one state.
 333                     if (r.pos==1)  rex = singularReductions.get(this.pending(), r);
 334                     if (rex==null) {
 335                         rex = r.rewrite(phase().getLocation());
 336                         if (r.pos==1) singularReductions.put(this.pending(), r, rex);
 337                     }
 338                     if (only != null)  only.finish(r, rex, target, holder);
 339                     else               for(Node child : this.parents()) child.finish(r, rex, target, holder);
 340                 } else {
 341                     if (only != null)  only.reduce(r, pos-1, target, holder);
 342                     else               for(Node child : this.parents()) child.reduce(r, pos-1, target, holder);
 343                 }
 344                 holder[pos] = old;
 345             }
 346
 347             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 348                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 349                 if (result==null) throw new Error();
 350                 if (state0!=null)
 351                     target.newNode(this, result, state0, r.pos<=0, r);
 352             }
 353
 354             private Node(Node parent, Forest pending, State state) {
 355                 this.state = state;
 356                 this.holder().merge(pending);
 357                 Phase start = parent==null ? null : parent.phase();
 358                 if (parent != null) parents().add(parent, true);
 359                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 360                 Phase.this.hash.put(state, start, this);
 361             }
 362             public int toInt() { return idx; }
 363             private final int idx = node_idx++;
 364         }
 365         private int node_idx = 0;
 366
 367         public int toInt() { return pos+1; }
 368         public int size() { return hash==null ? 0 : hash.size(); }
 369     }
 370
 371 }