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<Sequence,Phase.Waiting> waiting   = new HashMapBag<Sequence,Phase.Waiting>();
  22     HashMapBag<Integer,Sequence>       performed = new HashMapBag<Integer,Sequence>();
  23
  24     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  25     public class Phase implements Invokable<State, Forest, GSS.Phase.Node>, IntegerMappable {
  26         public int toInt() { return pos+1; }
  27
  28         /** the token immediately after this phase */
  29         public  final Token token;
  30
  31         boolean reducing;
  32
  33         /** currently this is necessary only for the code() hack -- it doesn't actually correspond to the input */
  34         private final int pos;
  35
  36         /** FIXME */
  37         public  Forest.Ref finalResult;
  38
  39         /** all nodes, keyed by the value returned by code() */
  40         /*private*/ IntPairMap<Phase.Node> hash;  /* ALLOC */
  41
  42         /** the number of nodes in this phase */
  43         private int numNodes;
  44
  45         boolean closed;
  46
  47         private boolean good;
  48         private Phase next = null;
  49
  50         private Token.Location location;
  51         public final Parser parser;
  52
  53         private Forest forest;
  54         Phase prev;
  55         public Phase(Phase prev, Parser parser, Phase previous, Token token, Token.Location location, Forest forest) {
  56             this.prev = prev;
  57             this.forest = forest;
  58             this.parser = parser;
  59             this.pos = previous==null ? 0 : previous.pos+1;
  60             this.token = token;
  61             this.location = location;
  62             inhibited.clear();
  63             reset();
  64         }
  65
  66         public void reset() {
  67             waiting.clear();
  68             performed.clear();
  69             hash = new IntPairMap<Phase.Node>();
  70             good = false;
  71             closed = false;
  72             numNodes = 0;
  73             reducing = false;
  74             finalResult = null;
  75             if (prev != null) prev.shift(this, forest);
  76         }
  77
  78         public void complain(Node n, HashMap<String,HashSet<String>> errors, boolean force) {
  79             if (n.touched) return;
  80             n.touched = true;
  81             for(Position p : n.state) {
  82                 if (((p.isFirst() || p.isLast()) && !force) || p.owner().name==null) {
  83                     for(Node n2 : n.parents())
  84                         complain(n2, errors, force | p.isFirst());
  85                 } else {
  86                     String seqname = p.owner().name;
  87                     HashSet<String> hs = errors.get(seqname);
  88                     if (hs==null) errors.put(seqname, hs = new HashSet<String>());
  89                     hs.add(p.element()+"");
  90                 }
  91             }
  92         }
  93
  94         public String black(Object o) { return "\033[30m"+o+"\033[0m"; }
  95         public String red(Object o) { return "\033[31m"+o+"\033[0m"; }
  96         public String green(Object o) { return "\033[32m"+o+"\033[0m"; }
  97         public String yellow(Object o) { return "\033[33m"+o+"\033[0m"; }
  98         public String blue(Object o) { return "\033[34m"+o+"\033[0m"; }
  99         public String purple(Object o) { return "\033[35m"+o+"\033[0m"; }
 100         public String cyan(Object o) { return "\033[36m"+o+"\033[0m"; }
 101         public String el(Object e) {
 102             String s = e.toString();
 103             if (s.length()==0 || s.charAt(0)!='\"' || s.charAt(s.length()-1)!='\"') return yellow(s);
 104             s = s.substring(1);
 105             s = s.substring(0, s.length()-1);
 106             StringBuffer ret = new StringBuffer();
 107             for(int i=0; i<s.length(); i++) {
 108                 if (s.charAt(i)=='\\' && i<s.length()-1) ret.append(s.charAt(++i));
 109                 else ret.append(s);
 110             }
 111             return purple(ret.toString());
 112         }
 113         public String error(String message) {
 114             String lookAhead = token==null ? "<EOF>" : token.toString();
 115             StringBuffer ret = new StringBuffer();
 116             ret.append("\n  ");
 117             ret.append(message);
 118             HashMap<String,HashSet<String>> errors = new HashMap<String,HashSet<String>>();
 119             for(Node n : hash.values()) {
 120                 //System.out.println(n.state);
 121                 complain(n, errors, false);
 122             }
 123             for(String s : errors.keySet()) {
 124                 ret.append("    while parsing " + yellow(s));
 125                 HashSet<String> hs = errors.get(s);
 126                 if (hs.size()==1) ret.append(" expected " + yellow(el(hs.iterator().next())) + "\n");
 127                 else {
 128                     ret.append(" expected ");
 129                     boolean first = true;
 130                     for(String s2 : hs) {
 131                         if (!first) ret.append(" or ");
 132                         first = false;
 133                         ret.append(yellow(el(s2)));
 134                     }
 135                     ret.append("\n");
 136                 }
 137             }
 138             return ret.toString();
 139         }
 140
 141         public boolean isDone() throws ParseFailed {
 142             if (token != null) return false;
 143             if (token==null && finalResult==null)
 144                 throw new ParseFailed(error(red("unexpected end of file\n")),
 145                                         getLocation());
 146             return true;
 147         }
 148
 149         public Token.Location getLocation() { return location; }
 150
 151         /** add a new node (merging with existing nodes if possible)
 152          *  @param parent             the parent of the new node
 153          *  @param result             the SPPF result corresponding to the new node
 154          *  @param state              the state that the new node is in
 155          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 156          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 157          */
 158         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 159             Node p = hash.get(state, parent==null?null:parent.phase());
 160             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 161             else            return newNode3(parent, pending, state, fromEmptyReduction);
 162         }
 163         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Reduction reduction) {
 164             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 165             Sequence owner = reduction==null ? null : reduction.position.owner();
 166             if (reduction!=null) {
 167                 if (inhibited.contains(pos, owner)) return;
 168                 if (owner.needs != null)
 169                     for(Sequence s : owner.needs)
 170                         if (!performed.contains(pos, s)) {
 171                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 172                             return;
 173                         }
 174                 if ((owner.needed != null && owner.needed.size()>0) ||
 175                     (owner.hated != null && owner.hated.size()>0) ||
 176                     (owner.hates != null && owner.hates.size()>0))
 177                     performed.add(pos, owner);
 178             }
 179             if (!owner.lame)
 180                 newNode(parent, pending, state, fromEmptyReduction);
 181             if (reduction!=null) inhibit(reduction, parent==null?0:parent.phase().pos);
 182             if (reduction != null) {
 183                 boolean redo = true;
 184                 while(redo) {
 185                     redo = false;
 186                     for(Waiting w : waiting.getAll(owner)) {
 187                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 188                             waiting.remove(owner, w);
 189                             w.perform();
 190                             redo = true;
 191                             break;
 192                         }
 193                     }
 194                 }
 195             }
 196         }
 197         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 198             p.holder.merge(pending);
 199             if (p.parents().contains(parent)) return true;
 200             p.parents().add(parent, true);
 201             if (p!=parent && !fromEmptyReduction) p.queueReductions(parent);
 202             return true;
 203         }
 204         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 205             do {
 206                 if (token != null && state.canShift(token)) break;
 207                 if (state.isAccepting()) break;
 208                 if (token==null) break;
 209                 if (!state.canReduce(token)) return false;
 210                 //if (count > 1) break;
 211                 //if (r.numPop == 0) break;
 212                 //r.reduce(pending, parent, null, Phase.this, null);
 213                 //return;
 214             } while(false);
 215
 216             Node n = new Node(parent, pending, state, fromEmptyReduction);  // ALLOC
 217             n.queueEmptyReductions();
 218             if (!fromEmptyReduction) n.queueReductions(parent);
 219             return true;
 220         }
 221
 222         public void uninhibit(int p, Sequence s) {
 223             if (s.hated!=null)
 224                 for(Sequence s2 : s.hated)
 225                     inhibited.remove(p, s2);
 226         }
 227
 228         public void inhibit(Reduction r, int p) {
 229             if (r.position.owner().hated == null) return;
 230             // remember that dead states are still allowed to shift -- just not allowed to reduce
 231             boolean reset = false;
 232             for(Sequence seq : r.position.owner().hated) {
 233                 if (performed.contains(p,seq)) {
 234                     uninhibit(p, seq);
 235                     //System.out.println("\nresetting due to " + r.position.owner() + " killing " + seq);
 236                     //inhibited.clear();
 237                     inhibited.add(p, seq);
 238                     //inhibited = new HashMapBag<Integer,Sequence>();
 239                     reset = true;
 240                     resets++;
 241                     throw new Reset();
 242                 }
 243                 inhibited.add(p, seq);
 244             }
 245         }
 246
 247         /** perform all reduction operations */
 248         public void reduce() {
 249             try {
 250                 reducing = true;
 251                 if (reducing_list==null || reducing_list.length < hash.size())
 252                     reducing_list = new Phase.Node[hash.size() * 4];
 253                 hash.toArray(reducing_list);
 254                 int num = hash.size();
 255                 for(int i=0; i<num; i++) {
 256                     Node n = reducing_list[i];
 257                     n.queueEmptyReductions();
 258                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 259                 }
 260                 for(int i=0; i<num; i++) {
 261                     Node n = reducing_list[i];
 262                     reducing_list[i] = null;
 263                     n.queueReductions();
 264                 }
 265             } catch (Reset r) {
 266                 reset();
 267                 reduce();
 268             }
 269         }
 270
 271         class Reset extends RuntimeException { }
 272
 273         public void invoke(State st, Forest result, Node n) {
 274             good |= next.newNode(n, result, st, false);
 275         }
 276
 277         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 278         public void shift(Phase next, Forest result) throws ParseFailed {
 279             if (prev!=null) prev.hash = null;
 280             this.next = next;
 281             closed = true;
 282             Forest res = null;
 283             boolean ok = false;
 284             for(Phase.Node n : hash.values()) {
 285                 if (token == null && n.state.isAccepting()) {
 286                     if (finalResult==null) finalResult = new Forest.Ref();
 287                     finalResult.merge(n.holder);
 288                 }
 289                 if (token == null) continue;
 290                 n.state.invokeShifts(token, this, result, n);
 291             }
 292
 293             if (!good && token!=null)
 294                 throw new ParseFailed(error(red("unexpected character")+" "+purple(token)+" encountered at "+green(getLocation())+"\n"),
 295                                         getLocation());
 296             if (token==null && finalResult==null)
 297                 throw new ParseFailed(error(red("unexpected end of file\n")),
 298                                         getLocation());
 299
 300             // this massively improves GC performance
 301             //hash = null;
 302         }
 303
 304
 305         public class Waiting {
 306             Node parent;
 307             Forest pending;
 308             State state;
 309             boolean fromEmptyReduction;
 310             Reduction reduction;
 311             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Reduction reduction) {
 312                 waits++;
 313                 this.parent = parent;
 314                 this.pending = pending;
 315                 this.state = state;
 316                 this.fromEmptyReduction = fromEmptyReduction;
 317                 this.reduction = reduction;
 318             }
 319             public void perform() {
 320                 //System.out.println("performing: " + reduction.position);
 321                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 322             }
 323         }
 324
 325         // GSS Nodes //////////////////////////////////////////////////////////////////////////////
 326
 327         /** a node in the GSS */
 328         public final class Node extends FastSet<Node> implements Invokable<Reduction, Node, Node> {
 329
 330             public boolean touched = false;
 331             private Forest.Ref holder = null;
 332             private boolean allqueued = false;
 333
 334             /** what state this node is in */
 335             public final State state;
 336
 337             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 338             public Phase phase() { return Phase.this; }
 339
 340             public  Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
 341             public  Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
 342             public  FastSet<Node> parents() { return this; }
 343
 344             public void queueReductions() {
 345                 if (!reducing) return;
 346                 if (allqueued) return;
 347                 allqueued = true;
 348                 int where = parents().size();
 349                 state.invokeReductions(token, this, this, null);
 350             }
 351
 352             public void queueReductions(Node n2) {
 353                 if (!allqueued) { queueReductions(); return; }
 354                 state.invokeReductions(token, this, this, n2);
 355             }
 356
 357             public final void invoke(Reduction r, Node n, Node n2) {
 358                 if (n==null) {
 359                     if (r.position.pos==0) r.reduce(this);
 360                     return;
 361                 }
 362                 if (r.position.pos==0) return;
 363                 if (n2==null) r.reduce(n);
 364                 else          r.reduce(n, n2);
 365             }
 366             public void queueEmptyReductions() {
 367                 if (!reducing) return;
 368                 state.invokeReductions(token, this, null, null);
 369             }
 370
 371             private boolean fe;
 372             public boolean dead = false;
 373             public boolean redo = false;
 374             private Node(Node parent, Forest pending, State state, boolean fe) {
 375                 this.fe = fe;
 376                 this.state = state;
 377                 this.holder().merge(pending);
 378                 Phase start = parent==null ? null : parent.phase();
 379                 if (parent != null) parents().add(parent, true);
 380                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 381                 Phase.this.hash.put(state, start, this);
 382                 Phase.this.numNodes++;
 383             }
 384         }
 385
 386     }
 387
 388     /** helper method */
 389     private static boolean equal(Object a, Object b) {
 390         if (a==null && b==null) return true;
 391         if (a==null || b==null) return false;
 392         return a.equals(b);
 393     }
 394 }