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 GSS() { }
  14
  15     private Phase.Node[] reducing_list = null;
  16     public int resets = 0;
  17     public int waits = 0;
  18
  19     HashMapBag<Integer,Sequence>       inhibited       = new HashMapBag<Integer,Sequence>();
  20     HashMapBag<Integer,Sequence>       expectedInhibit = new HashMapBag<Integer,Sequence>();
  21     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  22     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  23
  24     /** FIXME */
  25     public  Forest.Ref finalResult;
  26
  27     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  28     public class Phase<Tok> implements Invokable<State, Forest, Phase<Tok>.Node>, IntegerMappable {
  29
  30         public void invoke(State st, Forest result, Node n) {
  31             good |= next.newNode(n, result, st, false);
  32         }
  33
  34         /** the token immediately after this phase */
  35         final Tok token;
  36
  37         private final int pos;
  38
  39         boolean reducing;
  40         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  41         private IntPairMap<Forest> singularReductions;  /* ALLOC */
  42         private boolean closed;
  43         private boolean good;
  44         private Phase next = null;
  45         private Phase prev;
  46         private Input.Location location;
  47         public final Parser parser;
  48
  49         private Forest forest;
  50
  51         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Forest forest) {
  52             this.prev = prev;
  53             this.forest = forest;
  54             this.parser = parser;
  55             this.pos = previous==null ? 0 : previous.pos+1;
  56             this.token = token;
  57             this.location = location;
  58             inhibited.clear();
  59             reset();
  60         }
  61
  62         public void reset() {
  63             waiting.clear();
  64             performed.clear();
  65             hash = new IntPairMap<Phase.Node>();
  66             singularReductions = new IntPairMap<Forest>();
  67             expectedInhibit.clear();
  68             expectedInhibit.addAll(inhibited);
  69             good = false;
  70             closed = false;
  71             reducing = false;
  72             finalResult = null;
  73             if (prev != null) prev.shift(this, forest);
  74         }
  75
  76
  77         public boolean isDone() throws ParseFailed {
  78             if (token != null) return false;
  79             if (token==null && finalResult==null)
  80                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  81             return true;
  82         }
  83
  84         public Input.Location getLocation() { return location; }
  85
  86         /** add a new node (merging with existing nodes if possible)
  87          *  @param parent             the parent of the new node
  88          *  @param result             the SPPF result corresponding to the new node
  89          *  @param state              the state that the new node is in
  90          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
  91          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
  92          */
  93         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
  94             Node p = hash.get(state, parent==null?null:parent.phase());
  95             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
  96             else            return newNode3(parent, pending, state, fromEmptyReduction);
  97         }
  98         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
  99             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 100             Sequence owner = reduction==null ? null : reduction.owner();
 101             if (reduction!=null) {
 102                 if (inhibited.contains(pos, owner)) return;
 103                 if (owner.needs != null)
 104                     for(Sequence s : owner.needs)
 105                         if (!performed.contains(pos, s)) {
 106                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 107                             return;
 108                         }
 109                 if ((owner.needed != null && owner.needed.size()>0) ||
 110                     (owner.hated != null && owner.hated.size()>0) ||
 111                     (owner.hates != null && owner.hates.size()>0))
 112                     performed.add(pos, owner);
 113             }
 114             if (!owner.lame)
 115                 newNode(parent, pending, state, fromEmptyReduction);
 116             if (reduction!=null) inhibit(reduction, parent==null?0:parent.phase().pos);
 117             if (reduction != null) {
 118                 boolean redo = true;
 119                 while(redo) {
 120                     redo = false;
 121                     for(Waiting w : waiting.getAll(owner)) {
 122                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 123                             waiting.remove(owner, w);
 124                             w.perform();
 125                             redo = true;
 126                             break;
 127                         }
 128                     }
 129                 }
 130             }
 131         }
 132         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 133             p.holder.merge(pending);
 134             if (p.parents().contains(parent)) return true;
 135             p.parents().add(parent, true);
 136             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 137             return true;
 138         }
 139         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 140             do {
 141                 if (token != null && state.canShift(token)) break;
 142                 if (state.isAccepting()) break;
 143                 if (token==null) break;
 144                 if (!state.canReduce(token)) return false;
 145                 //if (count > 1) break;
 146                 //if (r.numPop == 0) break;
 147                 //r.reduce(pending, parent, null, Phase.this, null);
 148                 //return;
 149             } while(false);
 150
 151             Node n = new Node(parent, pending, state);  // ALLOC
 152             if (reducing) {
 153                 n.performEmptyReductions();
 154                 if (!fromEmptyReduction) n.performReductions(parent);
 155             }
 156             return true;
 157         }
 158
 159         public void uninhibit(int p, Sequence s) {
 160             if (s.hated!=null)
 161                 for(Sequence s2 : s.hated)
 162                     inhibited.remove(p, s2);
 163         }
 164
 165         public void inhibit(Position r, int p) {
 166             if (r.owner().hated == null) return;
 167             // remember that dead states are still allowed to shift -- just not allowed to reduce
 168             boolean reset = false;
 169             for(Sequence seq : r.owner().hated) {
 170                 if (performed.contains(p,seq)) {
 171                     uninhibit(p, seq);
 172                     //System.out.println("\nresetting due to " + r.owner() + " killing " + seq);
 173                     //inhibited.clear();
 174                     inhibited.add(p, seq);
 175                     //inhibited = new HashMapBag<Integer,Sequence>();
 176                     reset = true;
 177                     resets++;
 178                     throw new Reset();
 179                 }
 180                 inhibited.add(p, seq);
 181                 expectedInhibit.remove(p, seq);
 182             }
 183         }
 184
 185         /** perform all reduction operations */
 186         public void reduce() {
 187             try {
 188                 reducing = true;
 189                 if (reducing_list==null || reducing_list.length < hash.size())
 190                     reducing_list = new Phase.Node[hash.size() * 4];
 191                 hash.toArray(reducing_list);
 192                 int num = hash.size();
 193                 for(int i=0; i<num; i++) {
 194                     Node n = reducing_list[i];
 195                     n.performEmptyReductions();
 196                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 197                 }
 198                 for(int i=0; i<num; i++) {
 199                     Node n = reducing_list[i];
 200                     reducing_list[i] = null;
 201                     n.performReductions();
 202                 }
 203                 if (expectedInhibit.size() > 0) {
 204                     inhibited.removeAll(expectedInhibit);
 205                     System.out.println("\n!!!!\n");
 206                     throw new Reset();
 207                 }
 208             } catch (Reset r) {
 209                 reset();
 210                 reduce();
 211             }
 212         }
 213
 214         class Reset extends RuntimeException { }
 215
 216         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 217         public void shift(Phase next, Forest result) throws ParseFailed {
 218             // this massively improves GC performance
 219             if (prev!=null) {
 220                 prev.hash = null;
 221                 prev.singularReductions = null;
 222             }
 223             this.next = next;
 224             closed = true;
 225             Forest res = null;
 226             boolean ok = false;
 227             for(Phase.Node n : hash.values()) {
 228                 if (token == null && n.state.isAccepting()) {
 229                     if (finalResult==null) finalResult = new Forest.Ref();
 230                     finalResult.merge(n.holder);
 231                 }
 232                 if (token == null) continue;
 233                 n.state.invokeShifts(token, this, result, n);
 234             }
 235
 236             if (!good && token!=null)
 237                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 238                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 239                                                         "\' encountered at "+
 240                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 241                                         getLocation());
 242             if (token==null && finalResult==null)
 243                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 244                                         getLocation());
 245         }
 246
 247
 248         public class Waiting {
 249             Node parent;
 250             Forest pending;
 251             State state;
 252             boolean fromEmptyReduction;
 253             Position reduction;
 254             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 255                 waits++;
 256                 this.parent = parent;
 257                 this.pending = pending;
 258                 this.state = state;
 259                 this.fromEmptyReduction = fromEmptyReduction;
 260                 this.reduction = reduction;
 261             }
 262             public void perform() {
 263                 //System.out.println("performing: " + reduction.position);
 264                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 265             }
 266         }
 267
 268         // Node /////////////////////////////////////////////////////////////////////////////////
 269
 270         /** a node in the GSS */
 271         public final class Node extends FastSet<Node> implements Invokable<Position, Node, Node>, IntegerMappable {
 272
 273             private Forest.Ref holder = null;
 274             private boolean allqueued = false;
 275
 276             /** what state this node is in */
 277             public final Parser.Table<Tok>.State<Tok> state;
 278
 279             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 280             public  Phase phase() { return Phase.this; }
 281             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 282             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 283             public  FastSet<Node> parents() { return this; }
 284
 285             public void performReductions() {
 286                 if (allqueued) return;
 287                 allqueued = true;
 288                 state.invokeReductions(token, this, this, null);
 289             }
 290
 291             public void performReductions(Node n2) {
 292                 if (!allqueued) performReductions();
 293                 else            state.invokeReductions(token, this, this, n2);
 294             }
 295
 296             public final void invoke(Position r, Node n, Node n2) {
 297                 if (n==null || n2==null || r.pos==0) {
 298                     if (r.pos==0) {
 299                         if (n==null) n = this;
 300                         else return;
 301                     }
 302                     if (n==null) return;
 303                     Forest[] holder = new Forest[r.pos];
 304                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 305                     else                   n.reduce(r, r.pos-1, n.phase(), holder);
 306                 } else {
 307                     Forest[] holder = new Forest[r.pos];
 308                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 309                     int pos = r.pos-1;
 310                     Forest old = holder[pos];
 311                     holder[pos] = n.pending();
 312                     if (pos==0) {
 313                         System.arraycopy(holder, 0, r.holder, 0, holder.length);
 314                         Forest rex = null;
 315                         if (r.pos==1)  rex = singularReductions.get(this, r);
 316                         if (rex==null) {
 317                             rex = r.rewrite(n.phase().getLocation());
 318                             if (r.pos==1) singularReductions.put(this, r, rex);
 319                         }
 320                         n2.finish(r, rex, n.phase(), holder);
 321                     } else {
 322                         n2.reduce(r, pos-1, n.phase(), holder);
 323                     }
 324                     holder[pos] = old;
 325                 }
 326             }
 327
 328             public void reduce(Position r, int pos, Phase target, Forest[] holder) {
 329                 Forest old = holder[pos];
 330                 holder[pos] = this.pending();
 331                 if (pos==0) {
 332                     System.arraycopy(holder, 0, r.holder, 0, holder.length);
 333                     for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 334                     Forest rex = null;
 335                     if (r.pos==1)  rex = singularReductions.get(this, r);
 336                     if (rex==null) {
 337                         rex = r.rewrite(phase().getLocation());
 338                         if (r.pos==1) singularReductions.put(this, r, rex);
 339                     }
 340                     for(Node child : this.parents()) child.finish(r, rex, target, holder);
 341                 } else {
 342                     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             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 355
 356             private Node(Node parent, Forest pending, State state) {
 357                 this.state = state;
 358                 this.holder().merge(pending);
 359                 Phase start = parent==null ? null : parent.phase();
 360                 if (parent != null) parents().add(parent, true);
 361                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 362                 Phase.this.hash.put(state, start, this);
 363             }
 364             public int toInt() { return idx; }
 365             private final int idx = node_idx++;
 366         }
 367         private int node_idx = 0;
 368
 369         public int toInt() { return pos+1; }
 370         public int size() { return hash==null ? 0 : hash.size(); }
 371     }
 372
 373 }