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.Sequence.Position;
   5 import edu.berkeley.sbp.Parser.Table.State;
   6 import edu.berkeley.sbp.Parser.Table.Reduction;
   7 import java.io.*;
   8 import java.util.*;
   9 import java.lang.reflect.*;
  10
  11 /** implements Tomita's Graph Structured Stack */
  12 class GSS {
  13
  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> assumed = 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     HashSet<Phase.Waiting> tail = new     HashSet<Phase.Waiting>();
  25
  26     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  27     public class Phase implements Invokable<State, Forest, GSS.Phase.Node> {
  28
  29         /** the token immediately after this phase */
  30         public  final Token token;
  31
  32         boolean reducing;
  33
  34         /** currently this is necessary only for the code() hack -- it doesn't actually correspond to the input */
  35         private final int pos;
  36
  37         /** FIXME */
  38         public  Forest.Ref finalResult;
  39
  40         /** all nodes, keyed by the value returned by code() */
  41         /*private*/ HashMap<Long,Phase.Node> hash;  /* ALLOC */
  42
  43         /** the number of nodes in this phase */
  44         private int numNodes;
  45
  46         boolean closed;
  47
  48         private boolean good;
  49         private Phase next = null;
  50
  51         private Token.Location location;
  52         public final Parser parser;
  53
  54         private Forest forest;
  55         Phase prev;
  56         public Phase(Phase prev, Parser parser, Phase previous, Token token, Token.Location location, Forest forest) {
  57             this.prev = prev;
  58             this.forest = forest;
  59             this.parser = parser;
  60             this.pos = previous==null ? 0 : previous.pos+1;
  61             this.token = token;
  62             this.location = location;
  63             inhibited.clear();
  64             assumed.clear();
  65             reset();
  66         }
  67
  68         public void reset() {
  69             tail.clear();
  70             waiting.clear();
  71             performed.clear();
  72             hash = new HashMap<Long,Phase.Node>();
  73             good = false;
  74             closed = false;
  75             numNodes = 0;
  76             reducing = false;
  77             finalResult = null;
  78             if (prev != null) prev.shift(this, forest);
  79         }
  80
  81         public void complain(Node n, HashMap<String,HashSet<String>> errors, boolean force) {
  82             if (n.touched) return;
  83             n.touched = true;
  84             for(Position p : n.state) {
  85                 //if (!p.isLast()) {
  86                 if (((p.isFirst() || p.isLast()) && !force) || p.owner().name==null) {
  87                     for(Node n2 : n.parents())
  88                         complain(n2, errors, force | p.isFirst());
  89                 } else {
  90                     String seqname = p.owner().name;
  91                     HashSet<String> hs = errors.get(seqname);
  92                     if (hs==null) errors.put(seqname, hs = new HashSet<String>());
  93                     hs.add(p.element()+"");
  94                     //String s = "  while parsing " + seqname + ": expected a " + p.element();
  95                         //"\n";
  96                     /*
  97                     s +=       "      parsed: ";
  98                     for(Position p2 = p.owner().firstp(); p2 != null && p2 != p && !p2.isLast(); p2 = p2.next()) s += (p2.element() + " ");
  99                     s += "\n";
 100                     s +=       "    expected: ";
 101                     for(Position p2 = p; p2 != null && !p2.isLast(); p2 = p2.next()) s += (p2.element() + " ");
 102                     */
 103                     //s += "\n";
 104                     //errors.add(s);
 105                 }
 106             }
 107         }
 108
 109         public String black(Object o) { return "\033[30m"+o+"\033[0m"; }
 110         public String red(Object o) { return "\033[31m"+o+"\033[0m"; }
 111         public String green(Object o) { return "\033[32m"+o+"\033[0m"; }
 112         public String yellow(Object o) { return "\033[33m"+o+"\033[0m"; }
 113         public String blue(Object o) { return "\033[34m"+o+"\033[0m"; }
 114         public String purple(Object o) { return "\033[35m"+o+"\033[0m"; }
 115         public String cyan(Object o) { return "\033[36m"+o+"\033[0m"; }
 116         public String el(Object e) {
 117             String s = e.toString();
 118             if (s.length()==0 || s.charAt(0)!='\"' || s.charAt(s.length()-1)!='\"') return yellow(s);
 119             s = s.substring(1);
 120             s = s.substring(0, s.length()-1);
 121             StringBuffer ret = new StringBuffer();
 122             for(int i=0; i<s.length(); i++) {
 123                 if (s.charAt(i)=='\\' && i<s.length()-1) ret.append(s.charAt(++i));
 124                 else ret.append(s);
 125             }
 126             return purple(ret.toString());
 127         }
 128         public String error(String message) {
 129             String lookAhead = token==null ? "<EOF>" : token.toString();
 130             StringBuffer ret = new StringBuffer();
 131             ret.append("\n  ");
 132             ret.append(message);
 133             HashMap<String,HashSet<String>> errors = new HashMap<String,HashSet<String>>();
 134             for(Node n : hash.values()) complain(n, errors, false);
 135             for(String s : errors.keySet()) {
 136                 ret.append("    while parsing " + yellow(s));
 137                 HashSet<String> hs = errors.get(s);
 138                 if (hs.size()==1) ret.append(" expected " + yellow(el(hs.iterator().next())) + "\n");
 139                 else {
 140                     ret.append(" expected ");
 141                     boolean first = true;
 142                     for(String s2 : hs) {
 143                         if (!first) ret.append(" or ");
 144                         first = false;
 145                         ret.append(yellow(el(s2)));
 146                     }
 147                     ret.append("\n");
 148                 }
 149             }
 150             return ret.toString();
 151         }
 152
 153         public boolean isDone() throws Parser.Failed {
 154             if (token != null) return false;
 155             if (token==null && finalResult==null)
 156                 throw new Parser.Failed(error(red("unexpected end of file\n")),
 157                                         getLocation());
 158             return true;
 159         }
 160
 161         public Token.Location getLocation() { return location; }
 162
 163         /** add a new node (merging with existing nodes if possible)
 164          *  @param parent             the parent of the new node
 165          *  @param result             the SPPF result corresponding to the new node
 166          *  @param state              the state that the new node is in
 167          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 168          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 169          */
 170         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 171             Node p = hash.get(code(state, parent==null?null:parent.phase()));
 172             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 173             else            return newNode3(parent, pending, state, fromEmptyReduction);
 174         }
 175         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Reduction reduction) {
 176             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 177             Sequence owner = reduction==null ? null : reduction.position.owner();
 178             if (reduction!=null) {
 179                 if (inhibited.contains(pos, owner)) return;
 180                 /*
 181                 if (assumed.contains(pos, owner)) {
 182                     tail.add(new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 183                     return;
 184                 }
 185                 */
 186                 if (owner.needs != null)
 187                     for(Sequence s : owner.needs)
 188                         if (!performed.contains(pos, s)) {
 189                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 190                             return;
 191                         }
 192                 if ((owner.needed != null && owner.needed.size()>0) ||
 193                     (owner.hated != null && owner.hated.size()>0) ||
 194                     (owner.hates != null && owner.hates.size()>0))
 195                     performed.add(pos, owner);
 196             }
 197             if (!owner.lame)
 198                 newNode(parent, pending, state, fromEmptyReduction);
 199             if (reduction!=null) inhibit(reduction, parent==null?0:parent.phase().pos);
 200             if (reduction != null) {
 201                 boolean redo = true;
 202                 while(redo) {
 203                     redo = false;
 204                     for(Waiting w : waiting.getAll(owner)) {
 205                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 206                             waiting.remove(owner, w);
 207                             w.perform();
 208                             redo = true;
 209                             break;
 210                         }
 211                     }
 212                 }
 213             }
 214         }
 215         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 216             p.holder.merge(pending);
 217             if (p.parents().contains(parent)) return true;
 218             p.parents().add(parent, true);
 219             if (p!=parent && !fromEmptyReduction) p.queueReductions(parent);
 220             return true;
 221         }
 222         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 223             do {
 224                 if (token != null && state.canShift(token)) break;
 225                 if (state.isAccepting()) break;
 226                 if (token==null) break;
 227                 //if (!state.canReduce(token)) return false;
 228                 //if (count > 1) break;
 229                 //if (r.numPop == 0) break;
 230                 //r.reduce(pending, parent, null, Phase.this, null);
 231                 //return;
 232             } while(false);
 233
 234             Node n = new Node(parent, pending, state, fromEmptyReduction);  // ALLOC
 235             n.queueEmptyReductions();
 236             if (!fromEmptyReduction) n.queueReductions(parent);
 237             return true;
 238         }
 239
 240         public void uninhibit(int p, Sequence s) {
 241             if (s.hated!=null)
 242                 for(Sequence s2 : s.hated)
 243                     inhibited.remove(p, s2);
 244         }
 245
 246         public void inhibit(Reduction r, int p) {
 247             if (r.position.owner().hated == null) return;
 248             // remember that dead states are still allowed to shift -- just not allowed to reduce
 249             boolean reset = false;
 250             for(Sequence seq : r.position.owner().hated) {
 251                 if (performed.contains(p,seq)) {
 252                     uninhibit(p, seq);
 253                     //System.out.println("\nresetting due to " + r.position.owner() + " killing " + seq);
 254                     //inhibited.clear();
 255                     inhibited.add(p, seq);
 256                     //assumed = inhibited;
 257                     //inhibited = new HashMapBag<Integer,Sequence>();
 258                     reset = true;
 259                     resets++;
 260                     throw new Reset();
 261                 }
 262                 inhibited.add(p, seq);
 263             }
 264         }
 265
 266         /** perform all reduction operations */
 267         public void reduce() {
 268             try {
 269                 reducing = true;
 270                 if (reducing_list==null || reducing_list.length < hash.size())
 271                     reducing_list = new Phase.Node[hash.size() * 4];
 272                 Collection<Node> hv = hash.values();
 273                 hv.toArray(reducing_list);
 274                 int num = hv.size();
 275                 for(int i=0; i<num; i++) {
 276                     Node n = reducing_list[i];
 277                     n.queueEmptyReductions();
 278                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 279                 }
 280                 for(int i=0; i<num; i++) {
 281                     Node n = reducing_list[i];
 282                     reducing_list[i] = null;
 283                     n.queueReductions();
 284                 }
 285                 //for(Waiting w : tail)
 286                 //w.perform();
 287             } catch (Reset r) {
 288                 reset();
 289                 reduce();
 290             }
 291         }
 292
 293         class Reset extends RuntimeException { }
 294
 295         public void invoke(State st, Forest result, Node n) {
 296             good |= next.newNode(n, result, st, false);
 297         }
 298
 299         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 300         public void shift(Phase next, Forest result) throws Parser.Failed {
 301             if (prev!=null) prev.hash = null;
 302             this.next = next;
 303             closed = true;
 304             Forest res = null;
 305             boolean ok = false;
 306             for(Phase.Node n : hash.values()) {
 307                 //if (n.holder().empty() && pos>0) continue;
 308                 if (token == null && n.state.isAccepting()) {
 309                     if (finalResult==null) finalResult = new Forest.Ref();
 310                     finalResult.merge(n.holder);
 311                 }
 312                 if (token == null) continue;
 313                 n.state.invokeShifts(token, this, result, n);
 314             }
 315
 316             if (!good && token!=null)
 317                 throw new Parser.Failed(error(red("unexpected character")+" "+purple(token)+" encountered at "+green(getLocation())+"\n"),
 318                                         getLocation());
 319             if (token==null && finalResult==null)
 320                 throw new Parser.Failed(error(red("unexpected end of file\n")),
 321                                         getLocation());
 322
 323             // this massively improves GC performance
 324             //hash = null;
 325         }
 326
 327
 328         public class Waiting {
 329             Node parent;
 330             Forest pending;
 331             State state;
 332             boolean fromEmptyReduction;
 333             Reduction reduction;
 334             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Reduction reduction) {
 335                 waits++;
 336                 this.parent = parent;
 337                 this.pending = pending;
 338                 this.state = state;
 339                 this.fromEmptyReduction = fromEmptyReduction;
 340                 this.reduction = reduction;
 341             }
 342             public void perform() {
 343                 //System.out.println("performing: " + reduction.position);
 344                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 345             }
 346         }
 347
 348         // GSS Nodes //////////////////////////////////////////////////////////////////////////////
 349
 350         /** a node in the GSS */
 351         public final class Node extends FastSet<Node> implements Invokable<Reduction, Node, Node> {
 352
 353             public boolean touched = false;
 354             private Forest.Ref holder = null;
 355             private boolean allqueued = false;
 356
 357             /** what state this node is in */
 358             public final State state;
 359
 360             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 361             public Phase phase() { return Phase.this; }
 362
 363             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 364             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 365             public  FastSet<Node> parents() { return this; }
 366
 367             public void queueReductions() {
 368                 if (!reducing) return;
 369                 if (allqueued) return;
 370                 allqueued = true;
 371                 int where = parents().size();
 372                 state.invokeReductions(token, this, this, null);
 373             }
 374
 375             public void queueReductions(Node n2) {
 376                 if (!allqueued) { queueReductions(); return; }
 377                 state.invokeReductions(token, this, this, n2);
 378             }
 379
 380             public final void invoke(Reduction r, Node n, Node n2) {
 381                 if (n==null) {
 382                     if (r.numPop==0) r.reduce(this);
 383                     return;
 384                 }
 385                 if (r.numPop==0) return;
 386                 if (n2==null) r.reduce(n);
 387                 else          r.reduce(n, n2);
 388             }
 389             public void queueEmptyReductions() {
 390                 if (!reducing) return;
 391                 state.invokeReductions(token, this, null, null);
 392             }
 393
 394             private boolean fe;
 395             public boolean dead = false;
 396             public boolean redo = false;
 397             private Node(Node parent, Forest pending, State state, boolean fe) {
 398                 this.fe = fe;
 399                 this.state = state;
 400                 this.holder().merge(pending);
 401                 //if (holder().empty()) throw new Error(holder()+"");
 402                 Phase start = parent==null ? null : parent.phase();
 403                 if (parent != null) parents().add(parent, true);
 404                 if (Phase.this.hash.get(code(state, start)) != null) throw new Error("severe problem!");
 405                 Phase.this.hash.put(code(state, start), this);
 406                 Phase.this.numNodes++;
 407             }
 408         }
 409
 410     }
 411
 412     /** helper method */
 413     private static boolean equal(Object a, Object b) {
 414         if (a==null && b==null) return true;
 415         if (a==null || b==null) return false;
 416         return a.equals(b);
 417     }
 418
 419     /** this is something of a hack right now */
 420     private static long code(State state, Phase start) {
 421         return (((long)state.idx) << 32) | (start==null ? 0 : (start.pos+1));
 422     }
 423 }