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package morfologik.fsa;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.TreeMap;
import com.carrotsearch.hppc.IntIntOpenHashMap;
/**
* Other FSA-related utilities not directly associated with the class hierarchy.
*/
public final class FSAUtils {
public final static class IntIntHolder {
public int a;
public int b;
public IntIntHolder(int a, int b) {
this.a = a;
this.b = b;
}
public IntIntHolder() {
}
}
/**
* Returns the right-language reachable from a given FSA node, formatted
* as an input for the graphviz package (expressed in the <code>dot</code>
* language).
*/
public static String toDot(FSA fsa, int node) {
try {
StringWriter w = new StringWriter();
toDot(w, fsa, node);
return w.toString();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Saves the right-language reachable from a given FSA node, formatted
* as an input for the graphviz package (expressed in the <code>dot</code>
* language), to the given writer.
*/
public static void toDot(Writer w, FSA fsa, int node) throws IOException {
w.write("digraph Automaton {\n");
w.write(" rankdir = LR;\n");
final BitSet visited = new BitSet();
w.write(" stop [shape=doublecircle,label=\"\"];\n");
w.write(" initial [shape=plaintext,label=\"\"];\n");
w.write(" initial -> " + node + "\n\n");
visitNode(w, 0, fsa, node, visited);
w.write("}\n");
}
private static void visitNode(Writer w, int d, FSA fsa, int s, BitSet visited) throws IOException {
visited.set(s);
w.write(" "); w.write(Integer.toString(s));
if (fsa.getFlags().contains(FSAFlags.NUMBERS)) {
int nodeNumber = fsa.getRightLanguageCount(s);
w.write(" [shape=circle,label=\"" + nodeNumber + "\"];\n");
} else {
w.write(" [shape=circle,label=\"\"];\n");
}
for (int arc = fsa.getFirstArc(s); arc != 0; arc = fsa.getNextArc(arc)) {
w.write(" ");
w.write(Integer.toString(s));
w.write(" -> ");
if (fsa.isArcTerminal(arc)) {
w.write("stop");
} else {
w.write(Integer.toString(fsa.getEndNode(arc)));
}
final byte label = fsa.getArcLabel(arc);
w.write(" [label=\"");
if (Character.isLetterOrDigit(label))
w.write((char) label);
else {
w.write("0x");
w.write(Integer.toHexString(label & 0xFF));
}
w.write("\"");
if (fsa.isArcFinal(arc)) w.write(" arrowhead=\"tee\"");
if (fsa instanceof FSA5) {
if (((FSA5) fsa).isNextSet(arc)) {
w.write(" color=\"blue\"");
}
}
w.write("]\n");
}
for (int arc = fsa.getFirstArc(s); arc != 0; arc = fsa.getNextArc(arc)) {
if (!fsa.isArcTerminal(arc)) {
int endNode = fsa.getEndNode(arc);
if (!visited.get(endNode)) {
visitNode(w, d + 1, fsa, endNode, visited);
}
}
}
}
/**
* All byte sequences generated as the right language of <code>state</code>.
*/
public static ArrayList<byte[]> rightLanguage(FSA fsa, int state) {
final ArrayList<byte[]> rl = new ArrayList<byte[]>();
final byte [] buffer = new byte [0];
descend(fsa, state, buffer, 0, rl);
return rl;
}
/**
* Recursive descend and collection of the right language.
*/
private static byte [] descend(FSA fsa, int state, byte [] b, int position, ArrayList<byte[]> rl) {
if (b.length <= position) {
b = Arrays.copyOf(b, position + 1);
}
for (int arc = fsa.getFirstArc(state); arc != 0; arc = fsa.getNextArc(arc)) {
b[position] = fsa.getArcLabel(arc);
if (fsa.isArcFinal(arc)) {
rl.add(Arrays.copyOf(b, position + 1));
}
if (!fsa.isArcTerminal(arc))
b = descend(fsa, fsa.getEndNode(arc), b, position + 1, rl);
}
return b;
}
/**
* Calculate fan-out ratio.
* @return The returned array: result[outgoing-arcs]
*/
public static TreeMap<Integer, Integer> calculateFanOuts(final FSA fsa, int root) {
final int [] result = new int [256];
fsa.visitInPreOrder(new StateVisitor() {
public boolean accept(int state) {
int count = 0;
for (int arc = fsa.getFirstArc(state); arc != 0; arc = fsa.getNextArc(arc))
count++;
result[count]++;
return true;
}
});
TreeMap<Integer, Integer> output = new TreeMap<Integer, Integer>();
int low = 1; // Omit #0, there is always a single node like that (dummy).
while (low < result.length && result[low] == 0) low++;
int high = result.length - 1;
while (high >= 0 && result[high] == 0) high--;
for (int i = low; i <= high; i++) {
output.put(i, result[i]);
}
return output;
}
/**
* Calculate the size of right language for each state in an FSA.
*/
public static IntIntOpenHashMap rightLanguageForAllStates(final FSA fsa) {
final IntIntOpenHashMap numbers = new IntIntOpenHashMap();
fsa.visitInPostOrder(new StateVisitor() {
public boolean accept(int state) {
int thisNodeNumber = 0;
for (int arc = fsa.getFirstArc(state); arc != 0; arc = fsa.getNextArc(arc)) {
thisNodeNumber +=
(fsa.isArcFinal(arc) ? 1 : 0) +
(fsa.isArcTerminal(arc) ? 0 : numbers.get(fsa.getEndNode(arc)));
}
numbers.put(state, thisNodeNumber);
return true;
}
});
return numbers;
}
}
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