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.merge(parent, pending)) return true;
 152             p.parents().add(parent, true);
 153             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 154             return true;
 155         }
 156
 157         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 158             do {
 159                 if (token != null && state.canShift(token)) break;
 160                 if (state.isAccepting()) break;
 161                 if (token==null) break;
 162                 if (!state.canReduce(token)) return false;
 163                 //if (count > 1) break;
 164                 //if (r.numPop == 0) break;
 165                 //r.reduce(pending, parent, null, Phase.this, null);
 166                 //return;
 167             } while(false);
 168
 169             Node n = new Node(parent, pending, state);  // ALLOC
 170             if (reducing) {
 171                 n.performEmptyReductions();
 172                 if (!fromEmptyReduction) n.performReductions(parent);
 173             }
 174             return true;
 175         }
 176
 177         /** perform all reduction operations */
 178         public void reduce() throws ParseFailed {
 179             try {
 180                 reducing = true;
 181                 if (reducing_list==null || reducing_list.length < hash.size())
 182                     reducing_list = new Phase.Node[hash.size() * 4];
 183                 hash.toArray(reducing_list);
 184                 int num = hash.size();
 185                 for(int i=0; i<num; i++) {
 186                     Node n = reducing_list[i];
 187                     n.performEmptyReductions();
 188                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 189                 }
 190                 for(int i=0; i<num; i++) {
 191                     Node n = reducing_list[i];
 192                     reducing_list[i] = null;
 193                     n.performReductions();
 194                 }
 195                 if (reset) {
 196                     reset = false;
 197                     resets++;
 198                     throw new Reset();
 199                 }
 200                 for(int i : expected)
 201                     for(Sequence s : expected.getAll(i))
 202                         if (!performed.contains(i, s)) {
 203                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 204                             resets++;
 205                             throw new Reset();
 206                         }
 207             } catch (Reset r) {
 208                 reset();
 209                 reduce();
 210             }
 211             count = 0;
 212         }
 213
 214         private boolean reset = false;
 215         class Reset extends RuntimeException { }
 216
 217         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 218         public void shift(Phase next, Forest result) throws ParseFailed {
 219             // this massively improves GC performance
 220             if (prev!=null && parser.helpgc) {
 221                 prev.hash = 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                     for(Object f : n.results())
 231                         finalResult.merge((Forest)f);
 232                 }
 233                 if (token == null) continue;
 234                 n.state.invokeShifts(token, this, result, n);
 235             }
 236
 237             if (!good && token!=null)
 238                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 239                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 240                                                         "\' encountered at "+
 241                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 242                                         getLocation());
 243             if (token==null && finalResult==null)
 244                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 245                                         getLocation());
 246         }
 247
 248
 249         class Waiting {
 250             Node parent;
 251             Forest pending;
 252             State state;
 253             boolean fromEmptyReduction;
 254             Position reduction;
 255             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 256                 waits++;
 257                 this.parent = parent;
 258                 this.pending = pending;
 259                 this.state = state;
 260                 this.fromEmptyReduction = fromEmptyReduction;
 261                 this.reduction = reduction;
 262             }
 263             public void perform() {
 264                 //System.out.println("performing: " + reduction.position);
 265                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 266             }
 267         }
 268
 269         // Node /////////////////////////////////////////////////////////////////////////////////
 270
 271         /** a node in the GSS */
 272         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 273             public FastSet<Node> set = new FastSet<Node>();
 274
 275
 276             private boolean allqueued = false;
 277
 278             /** what state this node is in */
 279             public final Parser.Table<Tok>.State<Tok> state;
 280
 281             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 282             public  Phase phase() { return Phase.this; }
 283
 284             private HashSet<Forest.Ref> resultMap = new HashSet<Forest.Ref>();
 285             public Iterable<Forest.Ref> results() { return resultMap; }
 286             public FastSet<Node> parents() { return set; }
 287             public boolean merge(Node parent, Forest result) {
 288                 for(Forest.Ref f : results()) {
 289                     if (f.parents.contains(parent) /* UGLY: */ && f.parents.size()==1) {
 290                         f.merge(result);
 291                         return true;
 292                     }
 293                 }
 294                 Forest.Ref f = new Forest.Ref();
 295                 f.parents.add(parent);
 296                 f.merge(result);
 297                 resultMap.add(f);
 298                 set.add(parent, true);
 299                 return false;
 300             }
 301
 302             public void performReductions() {
 303                 if (allqueued) return;
 304                 allqueued = true;
 305                 state.invokeReductions(token, this, this, null);
 306             }
 307
 308             public void performReductions(Node n2) {
 309                 if (!allqueued) performReductions();
 310                 else            state.invokeReductions(token, this, this, n2);
 311             }
 312
 313             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 314             public final void invoke(Position r, Node n, Node n2) {
 315                 if (n==null || n2==null || r.pos==0) {
 316                     if (r.pos==0) {
 317                         if (n==null) n = this;
 318                         else return;
 319                     }
 320                     if (n==null) return;
 321                     Forest[] holder = new Forest[r.pos];
 322                     if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
 323                     else          n.reduce(r, r.pos-1,  n.phase(), holder, null);
 324                 } else {
 325                     Forest[] holder = new Forest[r.pos];
 326                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 327                     int pos = r.pos-1;
 328                     n.reduce(r, pos, n.phase(), holder, n2);
 329                 }
 330             }
 331
 332             public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
 333                 holder = r.holder;
 334                 Forest old = holder[pos];
 335
 336                 for(Forest result : results())
 337                     for(Node child : ((Forest.Ref<?>)result).parents) {
 338                         if (only != null && child!=only) continue;
 339                         holder[pos] = result;
 340                         if (pos==0) {
 341                             //System.arraycopy(holder, 0, r.holder, 0, holder.length);
 342                             for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
 343                             child.finish(r, r.rewrite(phase().getLocation()), target, holder);
 344                         } else {
 345                             child.reduce(r, pos-1, target, holder, null);
 346                         }
 347                     }
 348
 349                 holder[pos] = old;
 350             }
 351
 352             public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
 353                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 354                 if (result==null) throw new Error();
 355                 if (state0!=null)
 356                     target.newNode(this, result, state0, r.pos<=0, r);
 357             }
 358
 359             private Node(Node parent, Forest pending, State state) {
 360                 this.state = state;
 361                 this.merge(parent, pending);
 362                 Phase start = parent==null ? null : parent.phase();
 363                 if (parent != null) parents().add(parent, true);
 364                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 365                 Phase.this.hash.put(state, start, this);
 366             }
 367             public int toInt() { return idx; }
 368             private final int idx = node_idx++;
 369
 370             // GraphViz //////////////////////////////////////////////////////////////////////////////
 371
 372             public GraphViz.Node toGraphViz(GraphViz gv) {
 373                 if (gv.hasNode(this)) return gv.createNode(this);
 374                 GraphViz.Node n = gv.createNode(this);
 375                 n.label = ""+state.toStringx();
 376                 n.shape = "rectangle";
 377                 n.fill = "green";
 378                 for(Forest result : results()) n.edge(result, "");
 379                 for(Node parent : parents()) n.edge(parent, "");
 380                 ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 381                 return n;
 382             }
 383             public boolean isTransparent() { return false; }
 384             public boolean isHidden() { return false; }
 385
 386         }
 387         private int node_idx = 0;
 388
 389         public int toInt() { return pos+1; }
 390         public int size() { return hash==null ? 0 : hash.size(); }
 391
 392         // GraphViz //////////////////////////////////////////////////////////////////////////////
 393
 394         public GraphViz.Node toGraphViz(GraphViz gv) {
 395             if (gv.hasNode(this)) return gv.createNode(this);
 396             GraphViz.Group g = gv.createGroup(this);
 397             g.label = "Phase " + pos;
 398             g.color = "gray";
 399             g.cluster = true;
 400             return g;
 401         }
 402         public boolean isTransparent() { return false; }
 403         public boolean isHidden() { return false; }
 404
 405     }
 406 }