1 // Copyright 2006 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.Position;
10 import java.lang.reflect.*;
12 /** implements Tomita's Graph Structured Stack */
16 private Parser parser;
17 public GSS(Input input, Parser parser) { this.input = input; this.parser = parser;}
18 public Input getInput() { return input; }
23 int numReductions = 0;
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> {
28 // FIXME: right now, these are the performance bottleneck
29 private HashMapBag<Integer,Sequence> performed = new HashMapBag<Integer,Sequence>();
31 public Forest.Many finalResult;
32 private PriorityQueue<Reduction> reductionQueue = new PriorityQueue<Reduction>();
34 public void addReduction(Reduction r) {
35 //System.out.println("+ " + r);
37 reductionQueue.add(r);
39 public void invoke(State st, Result result) {
41 good |= next.newNode(result, st, false);
44 /** the token immediately after this phase */
48 public IntPairMap<Node> hash = new IntPairMap<Node>(); /* ALLOC */
49 private boolean good = false;
50 private Phase next = null;
52 private Input.Location location;
53 private Input.Location nextLocation;
54 private Input.Location prevLocation;
56 private Forest forest;
58 public Phase(State startState) throws ParseFailed, IOException {
60 Result primordealResult = new Result(null, null, null);
61 newNode(primordealResult, startState, true);
63 public Phase(Phase prev, Forest forest) throws ParseFailed, IOException {
64 this.location = input.getLocation();
65 this.token = (Tok)input.next();
66 this.prevLocation = prev==null ? location : prev.getLocation();
69 this.pos = prev==null ? 0 : prev.pos+1;
70 this.nextLocation = input.getLocation();
71 if (prev != null) prev.shift(this, forest);
74 int minPhasePos = Integer.MAX_VALUE;
76 Reduction best = null;
77 //System.out.println("==============================================================================");
78 while(!reductionQueue.isEmpty()) {
79 Reduction r = reductionQueue.poll();
80 //System.out.println("- " + r);
81 if (r.parentPhase() != null)
82 if (r.parentPhase().pos > minPhasePos)
85 if (r.parentPhase() != null) {
86 if (r.parentPhase().pos < minPhasePos) {
87 minPhasePos = r.parentPhase().pos;
88 maxOrd = r.reduction().ord;
90 } else if (r.parentPhase().pos == minPhasePos) {
92 if (best != null && Parser.mastercache.comparePositions(r.reduction(), best.reduction()) < 0)
93 throw new Error("\n"+r+"\n"+best+"\n"+
94 Parser.mastercache.comparePositions(r.reduction(), best.reduction())+"\n"+r.compareTo(best)+
95 "\n"+(r.reduction().ord-best.reduction().ord));
97 maxOrd = r.reduction().ord;
103 if (token==null) shift(null, null);
106 public boolean isDone() throws ParseFailed {
107 if (token != null) return false;
108 if (token==null && finalResult==null)
109 ParseFailed.error("unexpected end of file", this);
113 public Input.Location getPrevLocation() { return prevLocation; }
114 public Input.Location getLocation() { return location; }
115 public Input.Region getRegion() { return getPrevLocation().createRegion(getLocation()); }
116 public Input.Location getNextLocation() { return nextLocation; }
117 public boolean isFrontier() { return hash!=null; }
119 /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
120 private void shift(Phase next, Forest result) throws ParseFailed {
122 // this massively improves GC performance
124 IntPairMap<Node> h = prev.hash;
126 prev.performed = null;
130 numOldNodes = hash.size();
131 for(Node n : hash.values()) {
132 if (token == null && n.state().isAccepting()) {
133 if (finalResult==null) finalResult = new Forest.Many();
135 finalResult.merge(r.getForest());
137 if (token == null) continue;
138 n.state().invokeShifts(token, this, new Result(result, n, null));
140 numNewNodes = next==null ? 0 : next.hash.size();
142 if (!good && token!=null) ParseFailed.error("unexpected character", this);
143 if (token==null && finalResult==null) ParseFailed.error("unexpected end of file", this);
144 for(Node n : hash) n.check();
147 void newNodeFromReduction(Result result, State state, Position reduction) {
148 int pos = result.phase().pos;
149 Sequence owner = reduction.owner();
150 for(Sequence s : owner.hates())
151 if (performed.contains(pos, s))
153 for(Sequence s : owner.needs())
154 if (!performed.contains(pos, s))
156 if (owner.needed_or_hated && !performed.contains(pos, owner))
157 performed.add(pos, owner);
159 newNode(result, state, reduction.pos<=0);
162 /** add a new node (merging with existing nodes if possible)
163 * @param parent the parent of the new node
164 * @param result the SPPF result corresponding to the new node
165 * @param state the state that the new node is in
166 * @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
167 * @param start the earliest part of the input contributing to this node (used to make merging decisions)
169 private boolean newNode(Result result, State state, boolean fromEmptyReduction) {
170 Node p = hash.get(state, result.phase());
171 if (p != null) { p.addResult(result); return true; }
173 if (token != null && state.canShift(token)) break;
174 if (state.isAccepting()) break;
175 if (token==null) break;
176 if (!state.canReduce(token)) return false;
178 Node n = new Node(Phase.this, result, state, fromEmptyReduction); // ALLOC
179 for(Object s : state.also)
180 newNode(new Result(null, n, null), (State)s, fromEmptyReduction);
184 public int toInt() { return pos+1; }
185 public int size() { return hash==null ? 0 : hash.size(); }
186 public int pos() { return pos; }
187 public Tok getToken() { return token; }
188 public Iterator<Node> iterator() { return hash.iterator(); }
189 public GSS getGSS() { return GSS.this; }
191 // GraphViz //////////////////////////////////////////////////////////////////////////////
193 public GraphViz.Node toGraphViz(GraphViz gv) {
194 if (gv.hasNode(this)) return gv.createNode(this);
195 GraphViz.Group g = gv.createGroup(this);
196 g.label = "Phase " + pos;
201 public boolean isTransparent() { return false; }
202 public boolean isHidden() { return false; }
204 public void dumpGraphViz(String filename) throws IOException {
205 FileOutputStream fos = new FileOutputStream(filename);
206 PrintWriter p = new PrintWriter(new OutputStreamWriter(fos));
207 GraphViz gv = new GraphViz();
209 ((Node)n).toGraphViz(gv);