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 /** which GSS.Phase this StateNode belongs to */
19 public GSS.Phase phase() { return phase; }
20 public Iterator<ResultNode> iterator() { return predecessors.iterator(); }
21 public Parser.Table.State state() { return state; }
23 boolean destroyed = false;
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.usedByAnyNode()) { dead = false; break; } }
35 else { if (r.usedByNonDoomedNode()) { dead = false; break; } }
36 dead |= predecessors.size()==0;
39 if (phase() != null && phase().hash != null)
40 phase().hash.remove(state, predPhase);
41 while(successors.size()>0)
42 for(ResultNode r : successors) {
47 while(predecessors.size()>0)
48 for(ResultNode r : predecessors) {
49 predecessors.remove(r);
57 //////////////////////////////////////////////////////////////////////
59 private final GSS.Phase phase;
60 private final GSS.Phase predPhase;
61 private final Parser.Table.State state;
62 private boolean fromEmptyReduction;
64 public final void invoke(Pos r, ResultNode only, Object o) {
65 boolean emptyProductions = only==null;
66 if (emptyProductions != (r.numPops()==0)) return;
67 if (r.numPops()!=0) reduce(r, r.numPops()-1, phase(), only);
69 Input.Region region = phase().getLocation().createRegion(phase().getLocation());
70 phase().newNodeFromReduction(r.rewrite(region), r, this);
74 private void reduce(Pos r, int pos, GSS.Phase target, ResultNode only) {
75 for(ResultNode res : predecessors)
76 if (only == null || res == only)
77 for(StateNode pred : res)
78 reduce2(r, pos, target, pred, res.getForest());
81 void reduce2(Pos r, int pos, GSS.Phase target, StateNode pred, Forest f) {
82 Forest[] holder = r.holder;
83 Forest old = pos >= holder.length ? null : holder[pos];
84 if (pos < holder.length) holder[pos] = f;
85 if (pos>0) pred.reduce(r, pos-1, target, null);
87 Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
88 new Reduction(pred, r, r.rewrite(region), target);
90 if (pos < holder.length) holder[pos] = old;
93 StateNode(GSS.Phase phase, Forest f, Pos reduction, StateNode pred, State state, boolean fromEmptyReduction) {
94 this(phase, new ResultNode(f, reduction, pred), state, fromEmptyReduction);
96 StateNode(GSS.Phase phase, ResultNode pred, State state, boolean fromEmptyReduction) {
99 this.fromEmptyReduction = fromEmptyReduction;
100 if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
101 this.predPhase = pred.phase();
102 phase.hash.put(state, pred.phase(), this);
104 predecessors.add(pred);
106 if (!fromEmptyReduction)
107 state.invokeReductions(phase().getToken(), this, pred);
109 state.invokeEpsilonReductions(phase().token, this);
112 // Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
114 public void removeSucc(ResultNode succ) {
115 successors.remove(succ);
118 public void removePred(ResultNode result) {
119 predecessors.remove(result);
122 public void addSucc(ResultNode succ) {
123 successors.add(succ);
125 public void addPred(Forest f, Pos reduction, StateNode pred) {
126 for(ResultNode r : predecessors)
127 if (r.predecessorsContains(pred)) {
131 ResultNode result = new ResultNode(f, reduction, pred);
132 predecessors.add(result);
133 result.addSucc(this);
134 if (!this.fromEmptyReduction) state.invokeReductions(phase().getToken(), this, result);