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>, IntegerMappable {
  28         public int toInt() { return pos+1; }
  29
  30         /** the token immediately after this phase */
  31         public  final Token token;
  32
  33         boolean reducing;
  34
  35         /** currently this is necessary only for the code() hack -- it doesn't actually correspond to the input */
  36         private final int pos;
  37
  38         /** FIXME */
  39         public  Forest.Ref finalResult;
  40
  41         /** all nodes, keyed by the value returned by code() */
  42         /*private*/ HashMap<Long,Phase.Node> hash;  /* ALLOC */
  43
  44         /** the number of nodes in this phase */
  45         private int numNodes;
  46
  47         boolean closed;
  48
  49         private boolean good;
  50         private Phase next = null;
  51
  52         private Token.Location location;
  53         public final Parser parser;
  54
  55         private Forest forest;
  56         Phase prev;
  57         public Phase(Phase prev, Parser parser, Phase previous, Token token, Token.Location location, Forest forest) {
  58             this.prev = prev;
  59             this.forest = forest;
  60             this.parser = parser;
  61             this.pos = previous==null ? 0 : previous.pos+1;
  62             this.token = token;
  63             this.location = location;
  64             inhibited.clear();
  65             assumed.clear();
  66             reset();
  67         }
  68
  69         public void reset() {
  70             tail.clear();
  71             waiting.clear();
  72             performed.clear();
  73             hash = new HashMap<Long,Phase.Node>();
  74             good = false;
  75             closed = false;
  76             numNodes = 0;
  77             reducing = false;
  78             finalResult = null;
  79             if (prev != null) prev.shift(this, forest);
  80         }
  81
  82         public void complain(Node n, HashMap<String,HashSet<String>> errors, boolean force) {
  83             if (n.touched) return;
  84             n.touched = true;
  85             for(Position p : n.state) {
  86                 //if (!p.isLast()) {
  87                 if (((p.isFirst() || p.isLast()) && !force) || p.owner().name==null) {
  88                     for(Node n2 : n.parents())
  89                         complain(n2, errors, force | p.isFirst());
  90                 } else {
  91                     String seqname = p.owner().name;
  92                     HashSet<String> hs = errors.get(seqname);
  93                     if (hs==null) errors.put(seqname, hs = new HashSet<String>());
  94                     hs.add(p.element()+"");
  95                     //String s = "  while parsing " + seqname + ": expected a " + p.element();
  96                         //"\n";
  97                     /*
  98                     s +=       "      parsed: ";
  99                     for(Position p2 = p.owner().firstp(); p2 != null && p2 != p && !p2.isLast(); p2 = p2.next()) s += (p2.element() + " ");
 100                     s += "\n";
 101                     s +=       "    expected: ";
 102                     for(Position p2 = p; p2 != null && !p2.isLast(); p2 = p2.next()) s += (p2.element() + " ");
 103                     */
 104                     //s += "\n";
 105                     //errors.add(s);
 106                 }
 107             }
 108         }
 109
 110         public String black(Object o) { return "\033[30m"+o+"\033[0m"; }
 111         public String red(Object o) { return "\033[31m"+o+"\033[0m"; }
 112         public String green(Object o) { return "\033[32m"+o+"\033[0m"; }
 113         public String yellow(Object o) { return "\033[33m"+o+"\033[0m"; }
 114         public String blue(Object o) { return "\033[34m"+o+"\033[0m"; }
 115         public String purple(Object o) { return "\033[35m"+o+"\033[0m"; }
 116         public String cyan(Object o) { return "\033[36m"+o+"\033[0m"; }
 117         public String el(Object e) {
 118             String s = e.toString();
 119             if (s.length()==0 || s.charAt(0)!='\"' || s.charAt(s.length()-1)!='\"') return yellow(s);
 120             s = s.substring(1);
 121             s = s.substring(0, s.length()-1);
 122             StringBuffer ret = new StringBuffer();
 123             for(int i=0; i<s.length(); i++) {
 124                 if (s.charAt(i)=='\\' && i<s.length()-1) ret.append(s.charAt(++i));
 125                 else ret.append(s);
 126             }
 127             return purple(ret.toString());
 128         }
 129         public String error(String message) {
 130             String lookAhead = token==null ? "<EOF>" : token.toString();
 131             StringBuffer ret = new StringBuffer();
 132             ret.append("\n  ");
 133             ret.append(message);
 134             HashMap<String,HashSet<String>> errors = new HashMap<String,HashSet<String>>();
 135             for(Node n : hash.values()) complain(n, errors, false);
 136             for(String s : errors.keySet()) {
 137                 ret.append("    while parsing " + yellow(s));
 138                 HashSet<String> hs = errors.get(s);
 139                 if (hs.size()==1) ret.append(" expected " + yellow(el(hs.iterator().next())) + "\n");
 140                 else {
 141                     ret.append(" expected ");
 142                     boolean first = true;
 143                     for(String s2 : hs) {
 144                         if (!first) ret.append(" or ");
 145                         first = false;
 146                         ret.append(yellow(el(s2)));
 147                     }
 148                     ret.append("\n");
 149                 }
 150             }
 151             return ret.toString();
 152         }
 153
 154         public boolean isDone() throws Parser.Failed {
 155             if (token != null) return false;
 156             if (token==null && finalResult==null)
 157                 throw new Parser.Failed(error(red("unexpected end of file\n")),
 158                                         getLocation());
 159             return true;
 160         }
 161
 162         public Token.Location getLocation() { return location; }
 163
 164         /** add a new node (merging with existing nodes if possible)
 165          *  @param parent             the parent of the new node
 166          *  @param result             the SPPF result corresponding to the new node
 167          *  @param state              the state that the new node is in
 168          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 169          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 170          */
 171         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 172             Node p = hash.get(code(state, parent==null?null:parent.phase()));
 173             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 174             else            return newNode3(parent, pending, state, fromEmptyReduction);
 175         }
 176         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Reduction reduction) {
 177             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 178             Sequence owner = reduction==null ? null : reduction.position.owner();
 179             if (reduction!=null) {
 180                 if (inhibited.contains(pos, owner)) return;
 181                 /*
 182                 if (assumed.contains(pos, owner)) {
 183                     tail.add(new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 184                     return;
 185                 }
 186                 */
 187                 if (owner.needs != null)
 188                     for(Sequence s : owner.needs)
 189                         if (!performed.contains(pos, s)) {
 190                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 191                             return;
 192                         }
 193                 if ((owner.needed != null && owner.needed.size()>0) ||
 194                     (owner.hated != null && owner.hated.size()>0) ||
 195                     (owner.hates != null && owner.hates.size()>0))
 196                     performed.add(pos, owner);
 197             }
 198             if (!owner.lame)
 199                 newNode(parent, pending, state, fromEmptyReduction);
 200             if (reduction!=null) inhibit(reduction, parent==null?0:parent.phase().pos);
 201             if (reduction != null) {
 202                 boolean redo = true;
 203                 while(redo) {
 204                     redo = false;
 205                     for(Waiting w : waiting.getAll(owner)) {
 206                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 207                             waiting.remove(owner, w);
 208                             w.perform();
 209                             redo = true;
 210                             break;
 211                         }
 212                     }
 213                 }
 214             }
 215         }
 216         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 217             p.holder.merge(pending);
 218             if (p.parents().contains(parent)) return true;
 219             p.parents().add(parent, true);
 220             if (p!=parent && !fromEmptyReduction) p.queueReductions(parent);
 221             return true;
 222         }
 223         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 224             do {
 225                 if (token != null && state.canShift(token)) break;
 226                 if (state.isAccepting()) break;
 227                 if (token==null) break;
 228                 //if (!state.canReduce(token)) return false;
 229                 //if (count > 1) break;
 230                 //if (r.numPop == 0) break;
 231                 //r.reduce(pending, parent, null, Phase.this, null);
 232                 //return;
 233             } while(false);
 234
 235             Node n = new Node(parent, pending, state, fromEmptyReduction);  // ALLOC
 236             n.queueEmptyReductions();
 237             if (!fromEmptyReduction) n.queueReductions(parent);
 238             return true;
 239         }
 240
 241         public void uninhibit(int p, Sequence s) {
 242             if (s.hated!=null)
 243                 for(Sequence s2 : s.hated)
 244                     inhibited.remove(p, s2);
 245         }
 246
 247         public void inhibit(Reduction r, int p) {
 248             if (r.position.owner().hated == null) return;
 249             // remember that dead states are still allowed to shift -- just not allowed to reduce
 250             boolean reset = false;
 251             for(Sequence seq : r.position.owner().hated) {
 252                 if (performed.contains(p,seq)) {
 253                     uninhibit(p, seq);
 254                     //System.out.println("\nresetting due to " + r.position.owner() + " killing " + seq);
 255                     //inhibited.clear();
 256                     inhibited.add(p, seq);
 257                     //assumed = inhibited;
 258                     //inhibited = new HashMapBag<Integer,Sequence>();
 259                     reset = true;
 260                     resets++;
 261                     throw new Reset();
 262                 }
 263                 inhibited.add(p, seq);
 264             }
 265         }
 266
 267         /** perform all reduction operations */
 268         public void reduce() {
 269             try {
 270                 reducing = true;
 271                 if (reducing_list==null || reducing_list.length < hash.size())
 272                     reducing_list = new Phase.Node[hash.size() * 4];
 273                 Collection<Node> hv = hash.values();
 274                 hv.toArray(reducing_list);
 275                 int num = hv.size();
 276                 for(int i=0; i<num; i++) {
 277                     Node n = reducing_list[i];
 278                     n.queueEmptyReductions();
 279                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 280                 }
 281                 for(int i=0; i<num; i++) {
 282                     Node n = reducing_list[i];
 283                     reducing_list[i] = null;
 284                     n.queueReductions();
 285                 }
 286                 //for(Waiting w : tail)
 287                 //w.perform();
 288             } catch (Reset r) {
 289                 reset();
 290                 reduce();
 291             }
 292         }
 293
 294         class Reset extends RuntimeException { }
 295
 296         public void invoke(State st, Forest result, Node n) {
 297             good |= next.newNode(n, result, st, false);
 298         }
 299
 300         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 301         public void shift(Phase next, Forest result) throws Parser.Failed {
 302             if (prev!=null) prev.hash = null;
 303             this.next = next;
 304             closed = true;
 305             Forest res = null;
 306             boolean ok = false;
 307             for(Phase.Node n : hash.values()) {
 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                 Phase start = parent==null ? null : parent.phase();
 402                 if (parent != null) parents().add(parent, true);
 403                 if (Phase.this.hash.get(code(state, start)) != null) throw new Error("severe problem!");
 404                 Phase.this.hash.put(code(state, start), this);
 405                 Phase.this.numNodes++;
 406             }
 407         }
 408
 409     }
 410
 411     /** helper method */
 412     private static boolean equal(Object a, Object b) {
 413         if (a==null && b==null) return true;
 414         if (a==null || b==null) return false;
 415         return a.equals(b);
 416     }
 417
 418     /** this is something of a hack right now */
 419     private static long code(State state, Phase start) {
 420         return (((long)state.idx) << 32) | (start==null ? 0 : (start.pos+1));
 421     }
 422 }