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 final Parser.Table.State state;
20 /** which GSS.Phase this StateNode belongs to */
21 public Parser.Table.State state() { return state; }
22 public boolean isDoomedState() { return state.doomed; }
23 public boolean hasPathToRoot() {
24 if (state.doomed) return false;
25 return super.hasPathToRoot();
29 if (destroyed) return;
31 // - all nodes must have a predecessor
32 // - non-doomed nodes must either:
33 // - be on the frontier or
34 // - have a non-doomed node closer to the frontier than themself
35 if (phase().isFrontier()) dead = false;
36 else for(ResultNode r : successors())
37 if (state.doomed) { if (r.hasSuccessors()) { dead = false; break; } }
38 else { if (r.hasNonDoomedSuccessors()) { dead = false; break; } }
39 dead |= !hasPredecessors();
41 if (phase() != null && phase().hash != null)
42 phase().hash.remove(state, predecessorPhase());
46 public final void invoke(Pos r, ResultNode only, Object o) {
47 boolean emptyProductions = only==null;
48 if (emptyProductions != (r.numPops()==0)) return;
50 Input.Region region = phase().getLocation().createRegion(phase().getLocation());
51 phase().newNodeFromReduction(r.rewrite(region), r, this);
53 // never start reductions at a node that was created via a right-nulled rule
54 if (only.reduction() != null && only.reduction().numPops()==0) return;
55 reduce(r, r.numPops()-1, phase(), only);
59 private void reduce(Pos r, int pos, GSS.Phase target, ResultNode only) {
60 for(ResultNode res : this)
61 if (only == null || res == only)
62 for(StateNode pred : res) {
63 Forest[] holder = r.holder;
64 Forest old = pos >= holder.length ? null : holder[pos];
65 if (pos < holder.length) holder[pos] = res.getForest();
66 if (pos>0) pred.reduce(r, pos-1, target, null);
67 else new Reduction(pred, r,
69 ? r.rewrite(pred.phase().getLocation().createRegion(target.getLocation()))
72 if (pos < holder.length) holder[pos] = old;
76 StateNode(GSS.Phase phase, ResultNode pred, State state) {
77 super(phase, pred.phase());
79 if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
80 phase.hash.put(state, pred.phase(), this);
82 state.invokeEpsilonReductions(phase().token, this);
85 // Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
87 public void addPred(Forest f, Pos reduction, StateNode pred) {
88 for(ResultNode r : this)
89 if (r.predecessorsContains(pred)) {
93 addPred(new ResultNode(f, reduction, pred));
95 protected void addPred(ResultNode result) {
96 super.addPred(result);
97 state.invokeReductions(phase().getToken(), this, result);