1 // Copyright 2006-2007 all rights reserved; see LICENSE file for BSD-style license
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.Pos;
8 import edu.berkeley.sbp.Sequence.Pos;
11 import java.lang.reflect.*;
13 /** a node in the GSS */
15 extends Node<ResultNode>
16 implements Invokable<Pos, ResultNode, Object> {
18 private boolean fromEmptyReduction;
19 private final Parser.Table.State state;
21 /** which GSS.Phase this StateNode belongs to */
22 public Parser.Table.State state() { return state; }
23 public boolean isDoomedState() { return state.doomed; }
26 if (destroyed) return;
28 // - all nodes must have a predecessor
29 // - non-doomed nodes must either:
30 // - be on the frontier or
31 // - have a non-doomed node closer to the frontier than themself
32 if (phase().isFrontier()) dead = false;
33 else for(ResultNode r : successors)
34 if (state.doomed) { if (r.hasSuccessors()) { dead = false; break; } }
35 else { if (r.hasNonDoomedSuccessors()) { dead = false; break; } }
36 dead |= predecessors.size()==0;
38 if (phase() != null && phase().hash != null)
39 phase().hash.remove(state, predecessorPhase());
43 public final void invoke(Pos r, ResultNode only, Object o) {
44 boolean emptyProductions = only==null;
45 if (emptyProductions != (r.numPops()==0)) return;
47 Input.Region region = phase().getLocation().createRegion(phase().getLocation());
48 phase().newNodeFromReduction(r.rewrite(region), r, this);
50 // never start reductions at a node that was created via a right-nulled rule
51 if (only.reduction().numPops()==0) return;
52 reduce(r, r.numPops()-1, phase(), only);
56 private void reduce(Pos r, int pos, GSS.Phase target, ResultNode only) {
57 for(ResultNode res : predecessors)
58 if (only == null || res == only)
59 for(StateNode pred : res) {
60 Forest[] holder = r.holder;
61 Forest old = pos >= holder.length ? null : holder[pos];
62 if (pos < holder.length) holder[pos] = res.getForest();
63 if (pos>0) pred.reduce(r, pos-1, target, null);
65 Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
66 new Reduction(pred, r, r.rewrite(region), target);
68 if (pos < holder.length) holder[pos] = old;
72 StateNode(GSS.Phase phase, ResultNode pred, State state) {
73 super(phase, pred.phase());
75 this.fromEmptyReduction = pred!=null && pred.reduction()!=null && pred.reduction().numPops()==0;
76 if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
77 phase.hash.put(state, pred.phase(), this);
79 state.invokeEpsilonReductions(phase().token, this);
82 // Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
84 public void addPred(Forest f, Pos reduction, StateNode pred) {
85 for(ResultNode r : predecessors)
86 if (r.predecessorsContains(pred)) {
90 addPred(new ResultNode(f, reduction, pred));
92 protected void addPred(ResultNode result) {
93 super.addPred(result);
94 state.invokeReductions(phase().getToken(), this, result);