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;
19 private boolean fromEmptyReduction;
21 /** which GSS.Phase this StateNode belongs to */
22 public Iterator<ResultNode> iterator() { return predecessors.iterator(); }
23 public Parser.Table.State state() { return state; }
24 public boolean isDoomedState() { return state.doomed; }
27 if (destroyed) return;
29 // - all nodes must have a predecessor
30 // - non-doomed nodes must either:
31 // - be on the frontier or
32 // - have a non-doomed node closer to the frontier than themself
33 if (phase().isFrontier()) dead = false;
34 else for(ResultNode r : successors)
35 if (state.doomed) { if (r.hasSuccessors()) { dead = false; break; } }
36 else { if (r.hasNonDoomedSuccessors()) { dead = false; break; } }
37 dead |= predecessors.size()==0;
39 if (phase() != null && phase().hash != null)
40 phase().hash.remove(state, predecessorPhase());
44 public final void invoke(Pos r, ResultNode only, Object o) {
45 boolean emptyProductions = only==null;
46 if (emptyProductions != (r.numPops()==0)) return;
47 if (r.numPops()!=0) reduce(r, r.numPops()-1, phase(), only);
49 Input.Region region = phase().getLocation().createRegion(phase().getLocation());
50 phase().newNodeFromReduction(r.rewrite(region), r, this);
54 private void reduce(Pos r, int pos, GSS.Phase target, ResultNode only) {
55 for(ResultNode res : predecessors)
56 if (only == null || res == only)
57 for(StateNode pred : res)
58 reduce2(r, pos, target, pred, res.getForest());
61 void reduce2(Pos r, int pos, GSS.Phase target, StateNode pred, Forest f) {
62 Forest[] holder = r.holder;
63 Forest old = pos >= holder.length ? null : holder[pos];
64 if (pos < holder.length) holder[pos] = f;
65 if (pos>0) pred.reduce(r, pos-1, target, null);
67 Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
68 new Reduction(pred, r, r.rewrite(region), target);
70 if (pos < holder.length) holder[pos] = old;
73 StateNode(GSS.Phase phase, Forest f, Pos reduction, StateNode pred, State state, boolean fromEmptyReduction) {
74 this(phase, new ResultNode(f, reduction, pred), state, fromEmptyReduction);
76 StateNode(GSS.Phase phase, ResultNode pred, State state, boolean fromEmptyReduction) {
77 super(phase, pred.phase());
79 this.fromEmptyReduction = fromEmptyReduction;
80 if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
81 phase.hash.put(state, pred.phase(), this);
83 state.invokeEpsilonReductions(phase().token, this);
86 // Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
88 public void addPred(Forest f, Pos reduction, StateNode pred) {
89 for(ResultNode r : predecessors)
90 if (r.predecessorsContains(pred)) {
94 addPred(new ResultNode(f, reduction, pred));
96 protected void addPred(ResultNode result) {
97 super.addPred(result);
98 if (!this.fromEmptyReduction)
99 state.invokeReductions(phase().getToken(), this, result);