src/edu/berkeley/sbp/GSS.java

   1 // Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
   2
   3 package edu.berkeley.sbp;
   4 import edu.berkeley.sbp.*;
   5 import edu.berkeley.sbp.util.*;
   6 import edu.berkeley.sbp.Parser.Table.*;
   7 import edu.berkeley.sbp.Sequence.Position;
   8 import java.io.*;
   9 import java.util.*;
  10 import java.lang.reflect.*;
  11
  12 /** implements Tomita's Graph Structured Stack */
  13 class GSS {
  14
  15     Input input;
  16     private Parser parser;
  17     public GSS(Input input, Parser parser) { this.input = input; this.parser = parser;}
  18     public Input getInput() { return input; }
  19
  20     int numNewNodes = 0;
  21     int numOldNodes = 0;
  22     int viewPos = 0;
  23     int numReductions = 0;
  24
  25     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  26     class Phase<Tok> implements Invokable<State, Result>, IntegerMappable, GraphViz.ToGraphViz, Iterable<Node> {
  27
  28         // FIXME: right now, these are the performance bottleneck
  29         private HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  30
  31         public Forest.Many finalResult;
  32         private PriorityQueue<Reduction> reductionQueue = new PriorityQueue<Reduction>();
  33
  34         Parser parser() { return parser; }
  35         public void addReduction(Reduction r) {
  36             //System.out.println("+ " + r);
  37             parser.spin();
  38             reductionQueue.add(r);
  39         }
  40         public void invoke(State st, Result result) {
  41             parser.spin();
  42             good |= next.newNode(result, st, false);
  43         }
  44
  45         /** the token immediately after this phase */
  46         final Tok token;
  47         final int pos;
  48
  49         public IntPairMap<Node> hash = new IntPairMap<Node>();  /* ALLOC */
  50         private boolean good = false;
  51         private Phase next = null;
  52         private Phase prev;
  53         private Input.Location location;
  54         private Input.Location nextLocation;
  55
  56         private Forest forest;
  57
  58         public Phase(State startState) throws ParseFailed, IOException {
  59             this(null, null);
  60             Result primordealResult = new Result(null, null, null);
  61             newNode(primordealResult, startState, true);
  62         }
  63         public Phase(Phase prev, Forest forest) throws ParseFailed, IOException {
  64             this.location = input.getLocation();
  65             this.token = (Tok)input.next();
  66             this.nextLocation = input.getLocation();
  67             this.prev = prev;
  68             this.forest = forest;
  69             this.pos = prev==null ? 0 : prev.pos+1;
  70             if (prev != null) prev.shift(this, forest);
  71             numReductions = 0;
  72
  73             int minPhasePos = Integer.MAX_VALUE;
  74             int maxOrd = -1;
  75             Reduction best = null;
  76             //System.out.println("==============================================================================");
  77             while(!reductionQueue.isEmpty()) {
  78                 Reduction r = reductionQueue.poll();
  79                 //System.out.println("- " + r);
  80                 if (r.parentPhase() != null)
  81                     if (r.parentPhase().pos > minPhasePos)
  82                         throw new Error();
  83                 r.perform();
  84                 if (r.parentPhase() != null) {
  85                     if (r.parentPhase().pos < minPhasePos) {
  86                         minPhasePos = r.parentPhase().pos;
  87                         maxOrd = r.reduction().ord;
  88                         best = r;
  89                     } else if (r.parentPhase().pos == minPhasePos) {
  90                         /*
  91                         if (best != null && Parser.mastercache.comparePositions(r.reduction(), best.reduction()) < 0)
  92                             throw new Error("\n"+r+"\n"+best+"\n"+
  93                                             Parser.mastercache.comparePositions(r.reduction(), best.reduction())+"\n"+r.compareTo(best)+
  94                                             "\n"+(r.reduction().ord-best.reduction().ord));
  95                         */
  96                         maxOrd = r.reduction().ord;
  97                         best = r;
  98                     }
  99                 }
 100                 numReductions++;
 101             }
 102             if (token==null) shift(null, null);
 103         }
 104
 105         public boolean isDone() throws ParseFailed {
 106             if (token != null) return false;
 107             if (token==null && finalResult==null)
 108                 ParseFailed.error("unexpected end of file", this, null,
 109                                   getLocation().createRegion(getLocation()));
 110             return true;
 111         }
 112
 113         public Input.Location getLocation() { return location; }
 114         public Input.Location getNextLocation() { return nextLocation; }
 115         public boolean        isFrontier() { return hash!=null; }
 116
 117         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 118         private void shift(Phase next, Forest result) throws ParseFailed {
 119             this.next = next;
 120             // this massively improves GC performance
 121             if (prev != null) {
 122                 IntPairMap<Node> h = prev.hash;
 123                 prev.hash = null;
 124                 prev.performed = null;
 125                 for(Node n : h) n.check();
 126             }
 127             numOldNodes = hash.size();
 128             for(Node n : hash.values()) {
 129                 if (token == null && n.state().isAccepting()) {
 130                     if (finalResult==null) finalResult = new Forest.Many();
 131                     for(Result r : n)
 132                         finalResult.merge(r.getForest());
 133                 }
 134                 if (token == null) continue;
 135                 n.state().invokeShifts(token, this, new Result(result, n, null));
 136             }
 137             numNewNodes = next==null ? 0 : next.hash.size();
 138             viewPos = this.pos;
 139             if (!good && token!=null) {
 140                 String toks = token+"";
 141                 if (toks.length()==1 && toks.charAt(0) == edu.berkeley.sbp.chr.CharAtom.left) {
 142                     ParseFailed.error("unexpected increase in indentation", this,
 143                                       token, getRegionFromThisToNext());
 144                 } else if (toks.length()==1 && toks.charAt(0) == edu.berkeley.sbp.chr.CharAtom.right) {
 145                     ParseFailed.error("unexpected decrease in indentation", this,
 146                                       token, getRegionFromThisToNext());
 147                 } else {
 148                     ParseFailed.error("unexpected character '"+ANSI.cyan(StringUtil.escapify(token+"",
 149                                                                                              "\\\'\r\n"))+"'",
 150                                       this, token, getRegionFromThisToNext());
 151                 }
 152             }
 153             if (token==null && finalResult==null)
 154                 ParseFailed.error("unexpected end of file", this, null,
 155                                   getLocation().createRegion(getLocation()));
 156             for(Node n : hash) n.check();
 157         }
 158
 159         Input.Region getRegionFromThisToNext() {
 160             return getLocation().createRegion(getNextLocation());
 161         }
 162
 163         void newNodeFromReduction(Result result, State state, Position reduction) {
 164             int pos = result.phase().pos;
 165             Sequence owner = reduction.owner();
 166             for(Sequence s : owner.hates())
 167                 if (performed.contains(pos, s))
 168                     return;
 169             for(Sequence s : owner.needs())
 170                 if (!performed.contains(pos, s))
 171                     return;
 172             if (owner.needed_or_hated && !performed.contains(pos, owner))
 173                 performed.add(pos, owner);
 174             if (state!=null)
 175                 newNode(result, state, reduction.pos<=0);
 176         }
 177
 178         /** add a new node (merging with existing nodes if possible)
 179          *  @param parent             the parent of the new node
 180          *  @param result             the SPPF result corresponding to the new node
 181          *  @param state              the state that the new node is in
 182          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 183          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 184          */
 185         private boolean newNode(Result result, State state, boolean fromEmptyReduction) {
 186             Node p = hash.get(state, result.phase());
 187             if (p != null) { p.addResult(result); return !state.doomed(); }
 188             do {
 189                 if (token != null && state.canShift(token)) break;
 190                 if (state.isAccepting()) break;
 191                 if (token==null) break;
 192                 if (!state.canReduce(token)) return false;
 193             } while(false);
 194             Node n = new Node(Phase.this, result, state, fromEmptyReduction);  // ALLOC
 195             for(Object s : state.conjunctStates)
 196                 newNode(new Result(null, n, null), (State)s, fromEmptyReduction);
 197             return !n.state().doomed();
 198         }
 199
 200         public int toInt() { return pos+1; }
 201         public int size() { return hash==null ? 0 : hash.size(); }
 202         public int pos() { return pos; }
 203         public Tok getToken() { return token; }
 204         public Iterator<Node> iterator() { return hash.iterator(); }
 205         public GSS getGSS() { return GSS.this; }
 206
 207         // GraphViz //////////////////////////////////////////////////////////////////////////////
 208
 209         public GraphViz.Node toGraphViz(GraphViz gv) {
 210             if (gv.hasNode(this)) return gv.createNode(this);
 211             GraphViz.Group g = gv.createGroup(this);
 212             g.label = "Phase " + pos;
 213             g.color = "gray";
 214             g.cluster = true;
 215             return g;
 216         }
 217         public boolean isTransparent() { return false; }
 218         public boolean isHidden() { return false; }
 219
 220         public void dumpGraphViz(String filename) throws IOException {
 221             FileOutputStream fos = new FileOutputStream(filename);
 222             PrintWriter p = new PrintWriter(new OutputStreamWriter(fos));
 223             GraphViz gv = new GraphViz();
 224             for(Object n : this)
 225                 ((Node)n).toGraphViz(gv);
 226             gv.dump(p);
 227             p.flush();
 228             p.close();
 229         }
 230
 231     }
 232
 233 }