import java.util.*;
import java.lang.reflect.*;
-/** a node in the GSS */
-final class Node
- implements Invokable<Pos, Result>,
- IntegerMappable,
+abstract class Node<OtherNode extends Node>
+ implements IntegerMappable,
GraphViz.ToGraphViz,
- Iterable<Result> {
+ Iterable<OtherNode> {
- /** which GSS.Phase this Node belongs to */
- public GSS.Phase phase() { return phase; }
- public Iterator<Result> iterator() { return results.iterator(); }
- public Parser.Table.State state() { return state; }
+ private final GSS.Phase phase;
+ private final GSS.Phase predecessorPhase;
+ protected boolean destroyed = false;
+ private int numNonDoomedSuccessors = 0;
+ private boolean hasPathToRoot = false;
- public int toInt() { return idx; }
+ private FastSet<OtherNode> predecessors = new FastSet<OtherNode>();
+ private FastSet<OtherNode> successors = new FastSet<OtherNode>();
+ //protected HashSet<OtherNode> predecessors = new HashSet<OtherNode>();
+ //protected HashSet<OtherNode> successors = new HashSet<OtherNode>();
- boolean destroyed = false;
-
- public void check() {
- if (destroyed) return;
- boolean dead = true;
- // - all nodes must have a predecessor
- // - non-doomed nodes must either:
- // - be on the frontier or
- // - have a non-doomed node closer to the frontier than themself
- if (phase.isFrontier()) dead = false;
- else for(Result r : successors)
- if (state.doomed) { if (r.usedByAnyNode()) { dead = false; break; } }
- else { if (r.usedByNonDoomedNode()) { dead = false; break; } }
- dead |= results.size()==0;
- if (!dead) return;
- destroyed = true;
- while(successors.size()>0)
- for(Result r : successors) {
- successors.remove(r);
- r.destroy();
- break;
- }
- while(results.size()>0)
- for(Result r : results) {
- results.remove(r);
- r.removeSucc(this);
- break;
- }
- results = null;
- successors = null;
+ public GSS.Phase phase() { return phase; }
+ public GSS.Phase predecessorPhase() { return predecessorPhase; }
+ public boolean hasPredecessors() { return predecessors.size() > 0; }
+ public boolean hasSuccessors() { return successors.size() > 0; }
+ public boolean hasNonDoomedSuccessors() { return numNonDoomedSuccessors > 0; }
+
+ public boolean hasPathToRoot() { return hasPathToRoot; }
+ public void updatePathsToRootAfterRemoval() {
+ if (!hasPathToRoot()) return;
+ for(OtherNode on : predecessors)
+ if (on.hasPathToRoot())
+ return;
+ hasPathToRoot = false;
+ for(OtherNode on : successors)
+ on.updatePathsToRootAfterRemoval();
}
- //////////////////////////////////////////////////////////////////////
-
- private static int node_idx = 0;
- private final int idx = node_idx++;
-
- private final GSS.Phase phase;
- private final Parser.Table.State state;
- private final boolean fromEmptyReduction;
- //private FastSet<Result> results = new FastSet<Result>();
- private HashSet<Result> results = new HashSet<Result>();
- private HashSet<Result> successors = new HashSet<Result>();
-
- public final void invoke(Pos r, Result only) {
- boolean emptyProductions = only==null;
- if (emptyProductions != (r.numPops()==0)) return;
- if (r.numPops()!=0) reduce(r, r.numPops()-1, phase(), only);
- else {
- Input.Region region = phase().getLocation().createRegion(phase().getLocation());
- Result.newResult(r.rewrite(region), this, r, phase());
- }
+ /**
+ * Every Node has a phase; StateNodes belong to the phase in
+ * which they were shifted, ResultNodes belong to the phase of
+ * their predecessors. All of the predecessors of a given node
+ * must belong to the same phase
+ */
+ public Node(GSS.Phase phase, GSS.Phase predecessorPhase) {
+ this.phase = phase;
+ this.predecessorPhase = predecessorPhase;
}
- private void reduce(Pos r, int pos, GSS.Phase target, Result only) {
- Forest[] holder = r.holder;
- Forest old = holder[pos];
- if (results==null) return; // FIXME: this should not happen
- for(Result res : results)
- if (only == null || res == only) {
- Node pred = res.pred();
- holder[pos] = res.getForest();
- if (pos>0) pred.reduce(r, pos-1, target, null);
- else {
- Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
- new Reduction(pred, r, r.rewrite(region), target);
- }
- }
- holder[pos] = old;
+ /** only to be invoked (or overridden as public) by the subclass */
+ protected void addPred(OtherNode pred) {
+ if (predecessors.contains(pred)) throw new Error("a predecessor was added twice");
+ if (pred.phase() != predecessorPhase()) throw new Error();
+ predecessors.add(pred);
+ pred.addSucc(this);
+ if (pred.hasPathToRoot()) hasPathToRoot = true;
}
-
- Node(GSS.Phase phase, Result pred, State state, boolean fromEmptyReduction) {
- this.phase = phase;
- this.state = state;
- this.fromEmptyReduction = fromEmptyReduction;
- if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
- phase.hash.put(state, pred.phase(), this);
- addResult(pred);
- state.invokeEpsilonReductions(phase().token, this);
+ public void addSucc(OtherNode succ) {
+ if (successors.contains(succ)) throw new Error("a predecessor was added twice");
+ successors.add(succ);
+ numNonDoomedSuccessors += succ.isDoomedState() ? 0 : 1;
+ if (predecessors.size() > 1 && (((Object)this) instanceof ResultNode)) throw new Error();
}
- // Add/Remove Successors/Results //////////////////////////////////////////////////////////////////////////////
-
- public void removeSucc(Result succ) {
- if (successors==null) return;
+ protected void destroy() {
+ destroyed = true;
+ while(predecessors.size() > 0) {
+ OtherNode pred = predecessors.first();
+ removePred(pred);
+ pred.removeSucc(this);
+ }
+ predecessors = null;
+ while(successors.size() > 0) {
+ OtherNode succ = successors.first();
+ removeSucc(succ);
+ succ.removePred(this);
+ }
+ successors = null;
+ }
+ public void removeSucc(OtherNode succ) {
+ if (!successors.contains(succ)) return;
successors.remove(succ);
+ numNonDoomedSuccessors -= succ.isDoomedState() ? 0 : 1;
check();
}
- public void removeResult(Result result) {
- if (results==null) return;
- results.remove(result);
+ public void removePred(OtherNode pred) {
+ if (!predecessors.contains(pred)) return;
+ predecessors.remove(pred);
+ updatePathsToRootAfterRemoval();
check();
}
- public void addSucc(Result succ) {
- if (successors==null) return; // FIXME: this should not happen
- successors.add(succ);
- }
- public void addResult(Result r) {
- if (results.contains(r)) return;
- results.add(r);
- r.addSucc(this);
- if (!fromEmptyReduction) state.invokeReductions(phase().getToken(), this, r);
+
+
+ public abstract boolean isDoomedState();
+ protected abstract void check();
+
+ public Iterator<OtherNode> iterator() { return predecessors.iterator(); }
+ public Iterable<OtherNode> successors() { return successors; }
+
+ public boolean noSuccessors() { return successors.size()==0; }
+ public boolean predecessorsContains(OtherNode n) {
+ return predecessors.contains(n);
}
// GraphViz //////////////////////////////////////////////////////////////////////////////
- public GraphViz.Node toGraphViz(GraphViz gv) {
- if (results.size()==0) return null;
+ public GraphViz.StateNode toGraphViz(GraphViz gv) {
if (gv.hasNode(this)) return gv.createNode(this);
- GraphViz.Node n = gv.createNode(this);
+ GraphViz.StateNode n = gv.createNode(this);
+ /*
+ n.label = ""+f;
+ n.shape = "rectangle";
+ //if (pred()!=null) n.edge(pred, "");
+ n.color = "blue";
+ if (phase() != null)
+ ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
n.label = "state["+state.toInt()+"]";
n.shape = "rectangle";
boolean haspreds = false;
- for(Result r : results) n.edge(r, "");
+ for(ResultNode r : results) n.edge(r, "");
n.color = state.doomed ? "red" : "green";
((GraphViz.Group)phase().toGraphViz(gv)).add(n);
+ */
return n;
}
public boolean isTransparent() { return false; }
public boolean isHidden() { return false; }
-}
+ // IntegerMappable ////////////////////////////////////////////////////////////
+
+ private static int node_idx = 0;
+ private final int idx = node_idx++;
+ public int toInt() { return idx; }
+
+}
\ No newline at end of file
projects / sbp.git / blobdiff