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 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             performed.clear();
  61             reset();
  62         }
  63
  64         public void reset() throws ParseFailed {
  65             waiting.clear();
  66             expected.clear();
  67             lastperformed.clear();
  68             lastperformed.addAll(performed);
  69             performed.clear();
  70             hash = new IntPairMap<Phase.Node>();
  71             reset = false;
  72             good = false;
  73             closed = false;
  74             reducing = false;
  75             finalResult = null;
  76             if (prev != null) prev.shift(this, forest);
  77         }
  78
  79
  80         public boolean isDone() throws ParseFailed {
  81             if (token != null) return false;
  82             if (token==null && finalResult==null)
  83                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  84             return true;
  85         }
  86
  87         public Input.Location getLocation() { return location; }
  88
  89         /** add a new node (merging with existing nodes if possible)
  90          *  @param parent             the parent of the new node
  91          *  @param result             the SPPF result corresponding to the new node
  92          *  @param state              the state that the new node is in
  93          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
  94          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
  95          */
  96         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
  97             Node p = hash.get(state, parent==null?null:parent.phase());
  98             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
  99             else            return newNode3(parent, pending, state, fromEmptyReduction);
 100         }
 101         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 102             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 103             Sequence owner = reduction==null ? null : reduction.owner();
 104             if (reduction!=null) {
 105                 if (owner.hates!=null) {
 106                     for (Sequence s : performed.getAll(pos))
 107                         if (owner.hates.contains(s))
 108                             return;
 109                     for (Sequence s : lastperformed.getAll(pos))
 110                         if (owner.hates.contains(s)) {
 111                             //System.out.println("now expecting ["+pos+"] => " + s);
 112                             expected.add(pos, s);
 113                             return;
 114                         }
 115                 }
 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                 if (!performed.contains(pos, owner)) {
 123                     performed.add(pos, owner);
 124                     if (owner.hated != null)
 125                         for(Sequence seq : owner.hated)
 126                             if (performed.contains(pos, seq)) {
 127                                 performed.remove(pos, seq);
 128                                 reset = true;
 129                             }
 130                 }
 131             }
 132             if (!owner.lame)
 133                 newNode(parent, pending, state, fromEmptyReduction);
 134             if (reduction != null) {
 135                 boolean redo = true;
 136                 while(redo) {
 137                     redo = false;
 138                     for(Waiting w : waiting.getAll(owner)) {
 139                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 140                             waiting.remove(owner, w);
 141                             w.perform();
 142                             redo = true;
 143                             break;
 144                         }
 145                     }
 146                 }
 147             }
 148         }
 149
 150         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 151             //if (p.parents().contains(parent)) return true;
 152             if (p.merge(parent, pending)) return true;
 153             p.parents().add(parent, true);
 154             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 155             return true;
 156         }
 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             }
 224             this.next = next;
 225             closed = true;
 226             Forest res = null;
 227             boolean ok = false;
 228             for(Phase.Node n : hash.values()) {
 229                 if (token == null && n.state.isAccepting()) {
 230                     if (finalResult==null) finalResult = new Forest.Ref();
 231                     for(Object f : n.results())
 232                         finalResult.merge((Forest)f);
 233                 }
 234                 if (token == null) continue;
 235                 n.state.invokeShifts(token, this, result, n);
 236             }
 237
 238             if (!good && token!=null)
 239                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 240                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 241                                                         "\' encountered at "+
 242                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 243                                         getLocation());
 244             if (token==null && finalResult==null)
 245                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 246                                         getLocation());
 247         }
 248
 249
 250         class Waiting {
 251             Node parent;
 252             Forest pending;
 253             State state;
 254             boolean fromEmptyReduction;
 255             Position reduction;
 256             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 257                 waits++;
 258                 this.parent = parent;
 259                 this.pending = pending;
 260                 this.state = state;
 261                 this.fromEmptyReduction = fromEmptyReduction;
 262                 this.reduction = reduction;
 263             }
 264             public void perform() {
 265                 //System.out.println("performing: " + reduction.position);
 266                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 267             }
 268         }
 269
 270         // Node /////////////////////////////////////////////////////////////////////////////////
 271
 272         /** a node in the GSS */
 273         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 274             public FastSet<Node> set = new FastSet<Node>();
 275
 276         public GraphViz.Node toGraphViz(GraphViz gv) {
 277             if (gv.hasNode(this)) return gv.createNode(this);
 278             GraphViz.Node n = gv.createNode(this);
 279             n.label = ""+state.toStringx();
 280             n.shape = "rectangle";
 281             n.fill = "green";
 282             //GraphViz.Node f = pending().toGraphViz(gv);
 283             //n.add(f);
 284             for(Forest result : results()) n.edge(result, "");
 285             for(Node parent : parents()) n.edge(parent, "");
 286             ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 287             return n;
 288         }
 289         public boolean isTransparent() { return false; }
 290         public boolean isHidden() { return false; }
 291
 292             private boolean allqueued = false;
 293
 294             /** what state this node is in */
 295             public final Parser.Table<Tok>.State<Tok> state;
 296
 297             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 298             public  Phase phase() { return Phase.this; }
 299
 300             private HashSet<Forest.Ref> resultMap = new HashSet<Forest.Ref>();
 301             public Iterable<Forest.Ref> results() { return resultMap; }
 302             public FastSet<Node> parents() { return set; }
 303             public boolean merge(Node parent, Forest result) {
 304                 for(Forest.Ref f : results()) {
 305                     if (f.parents.contains(parent) /* UGLY: */ && f.parents.size()==1) {
 306                         f.merge(result);
 307                         return true;
 308                     }
 309                 }
 310                 Forest.Ref f = new Forest.Ref();
 311                 f.parents.add(parent);
 312                 f.merge(result);
 313                 resultMap.add(f);
 314                 set.add(parent, true);
 315                 return false;
 316             }
 317
 318             public void performReductions() {
 319                 if (allqueued) return;
 320                 allqueued = true;
 321                 state.invokeReductions(token, this, this, null);
 322             }
 323
 324             public void performReductions(Node n2) {
 325                 if (!allqueued) performReductions();
 326                 else            state.invokeReductions(token, this, this, n2);
 327             }
 328
 329             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 330             public final void invoke(Position r, Node n, Node n2) {
 331                 if (n==null || n2==null || r.pos==0) {
 332                     if (r.pos==0) {
 333                         if (n==null) n = this;
 334                         else return;
 335                     }
 336                     if (n==null) return;
 337                     Forest[] holder = new Forest[r.pos];
 338                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 339                     else          n.reduce(r, r.pos-1,  n.phase(), holder, null);
 340                 } else {
 341                     Forest[] holder = new Forest[r.pos];
 342                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 343                     int pos = r.pos-1;
 344                     n.reduce(r, pos, n.phase(), holder, n2);
 345                 }
 346             }
 347
 348             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 349                 Forest old = holder[pos];
 350
 351                 for(Forest result : results())
 352                     for(Node child : ((Forest.Ref<?>)result).parents) {
 353                         if (only != null && child!=only) continue;
 354                         holder[pos] = result;
 355                         if (pos==0) {
 356                             System.arraycopy(holder, 0, r.holder, 0, holder.length);
 357                             for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 358                             child.finish(r, r.rewrite(phase().getLocation()), target, holder);
 359                         } else {
 360                             child.reduce(r, pos-1, target, holder, null);
 361                         }
 362                     }
 363
 364                 holder[pos] = old;
 365             }
 366
 367             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 368                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 369                 if (result==null) throw new Error();
 370                 if (state0!=null)
 371                     target.newNode(this, result, state0, r.pos<=0, r);
 372             }
 373
 374             private Node(Node parent, Forest pending, State state) {
 375                 this.state = state;
 376                 this.merge(parent, pending);
 377                 Phase start = parent==null ? null : parent.phase();
 378                 if (parent != null) parents().add(parent, true);
 379                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 380                 Phase.this.hash.put(state, start, this);
 381             }
 382             public int toInt() { return idx; }
 383             private final int idx = node_idx++;
 384         }
 385         private int node_idx = 0;
 386
 387         public int toInt() { return pos+1; }
 388         public int size() { return hash==null ? 0 : hash.size(); }
 389
 390         // GraphViz //////////////////////////////////////////////////////////////////////////////
 391
 392         public GraphViz.Node toGraphViz(GraphViz gv) {
 393             if (gv.hasNode(this)) return gv.createNode(this);
 394             GraphViz.Group g = gv.createGroup(this);
 395             g.label = "Phase " + pos;
 396             g.color = "gray";
 397             g.cluster = true;
 398             return g;
 399         }
 400         public boolean isTransparent() { return false; }
 401         public boolean isHidden() { return false; }
 402
 403     }
 404 }