--- /dev/null
+package org.apache.lucene.util.fst;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.*;
+import java.util.*;
+
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.IntsRef;
+
+/** Static helper methods
+ *
+ * @lucene.experimental */
+public final class Util {
+ private Util() {
+ }
+
+ /** Looks up the output for this input, or null if the
+ * input is not accepted. FST must be
+ * INPUT_TYPE.BYTE4. */
+ public static<T> T get(FST<T> fst, IntsRef input) throws IOException {
+ assert fst.inputType == FST.INPUT_TYPE.BYTE4;
+
+ // TODO: would be nice not to alloc this on every lookup
+ final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
+
+ // Accumulate output as we go
+ final T NO_OUTPUT = fst.outputs.getNoOutput();
+ T output = NO_OUTPUT;
+ for(int i=0;i<input.length;i++) {
+ if (fst.findTargetArc(input.ints[input.offset + i], arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ output = fst.outputs.add(output, arc.output);
+ }
+ }
+
+ if (fst.findTargetArc(FST.END_LABEL, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ return fst.outputs.add(output, arc.output);
+ } else {
+ return output;
+ }
+ }
+
+ /** Logically casts input to UTF32 ints then looks up the output
+ * or null if the input is not accepted. FST must be
+ * INPUT_TYPE.BYTE4. */
+ public static<T> T get(FST<T> fst, char[] input, int offset, int length) throws IOException {
+ assert fst.inputType == FST.INPUT_TYPE.BYTE4;
+
+ // TODO: would be nice not to alloc this on every lookup
+ final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
+
+ int charIdx = offset;
+ final int charLimit = offset + length;
+
+ // Accumulate output as we go
+ final T NO_OUTPUT = fst.outputs.getNoOutput();
+ T output = NO_OUTPUT;
+ while(charIdx < charLimit) {
+ final int utf32 = Character.codePointAt(input, charIdx);
+ charIdx += Character.charCount(utf32);
+
+ if (fst.findTargetArc(utf32, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ output = fst.outputs.add(output, arc.output);
+ }
+ }
+
+ if (fst.findTargetArc(FST.END_LABEL, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ return fst.outputs.add(output, arc.output);
+ } else {
+ return output;
+ }
+ }
+
+
+ /** Logically casts input to UTF32 ints then looks up the output
+ * or null if the input is not accepted. FST must be
+ * INPUT_TYPE.BYTE4. */
+ public static<T> T get(FST<T> fst, CharSequence input) throws IOException {
+ assert fst.inputType == FST.INPUT_TYPE.BYTE4;
+
+ // TODO: would be nice not to alloc this on every lookup
+ final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
+
+ int charIdx = 0;
+ final int charLimit = input.length();
+
+ // Accumulate output as we go
+ final T NO_OUTPUT = fst.outputs.getNoOutput();
+ T output = NO_OUTPUT;
+
+ while(charIdx < charLimit) {
+ final int utf32 = Character.codePointAt(input, charIdx);
+ charIdx += Character.charCount(utf32);
+
+ if (fst.findTargetArc(utf32, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ output = fst.outputs.add(output, arc.output);
+ }
+ }
+
+ if (fst.findTargetArc(FST.END_LABEL, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ return fst.outputs.add(output, arc.output);
+ } else {
+ return output;
+ }
+ }
+
+ /** Looks up the output for this input, or null if the
+ * input is not accepted */
+ public static<T> T get(FST<T> fst, BytesRef input) throws IOException {
+ assert fst.inputType == FST.INPUT_TYPE.BYTE1;
+
+ // TODO: would be nice not to alloc this on every lookup
+ final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
+
+ // Accumulate output as we go
+ final T NO_OUTPUT = fst.outputs.getNoOutput();
+ T output = NO_OUTPUT;
+ for(int i=0;i<input.length;i++) {
+ if (fst.findTargetArc(input.bytes[i+input.offset] & 0xFF, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ output = fst.outputs.add(output, arc.output);
+ }
+ }
+
+ if (fst.findTargetArc(FST.END_LABEL, arc, arc) == null) {
+ return null;
+ } else if (arc.output != NO_OUTPUT) {
+ return fst.outputs.add(output, arc.output);
+ } else {
+ return output;
+ }
+ }
+
+ /**
+ * Dumps an {@link FST} to a GraphViz's <code>dot</code> language description
+ * for visualization. Example of use:
+ *
+ * <pre>
+ * PrintStream ps = new PrintStream("out.dot");
+ * fst.toDot(ps);
+ * ps.close();
+ * </pre>
+ *
+ * and then, from command line:
+ *
+ * <pre>
+ * dot -Tpng -o out.png out.dot
+ * </pre>
+ *
+ * <p>
+ * Note: larger FSTs (a few thousand nodes) won't even render, don't bother.
+ *
+ * @param sameRank
+ * If <code>true</code>, the resulting <code>dot</code> file will try
+ * to order states in layers of breadth-first traversal. This may
+ * mess up arcs, but makes the output FST's structure a bit clearer.
+ *
+ * @param labelStates
+ * If <code>true</code> states will have labels equal to their offsets in their
+ * binary format. Expands the graph considerably.
+ *
+ * @see "http://www.graphviz.org/"
+ */
+ public static <T> void toDot(FST<T> fst, Writer out, boolean sameRank, boolean labelStates)
+ throws IOException {
+ final String expandedNodeColor = "blue";
+
+ // This is the start arc in the automaton (from the epsilon state to the first state
+ // with outgoing transitions.
+ final FST.Arc<T> startArc = fst.getFirstArc(new FST.Arc<T>());
+
+ // A queue of transitions to consider for the next level.
+ final List<FST.Arc<T>> thisLevelQueue = new ArrayList<FST.Arc<T>>();
+
+ // A queue of transitions to consider when processing the next level.
+ final List<FST.Arc<T>> nextLevelQueue = new ArrayList<FST.Arc<T>>();
+ nextLevelQueue.add(startArc);
+
+ // A list of states on the same level (for ranking).
+ final List<Integer> sameLevelStates = new ArrayList<Integer>();
+
+ // A bitset of already seen states (target offset).
+ final BitSet seen = new BitSet();
+ seen.set(startArc.target);
+
+ // Shape for states.
+ final String stateShape = "circle";
+
+ // Emit DOT prologue.
+ out.write("digraph FST {\n");
+ out.write(" rankdir = LR; splines=true; concentrate=true; ordering=out; ranksep=2.5; \n");
+
+ if (!labelStates) {
+ out.write(" node [shape=circle, width=.2, height=.2, style=filled]\n");
+ }
+
+ emitDotState(out, "initial", "point", "white", "");
+ emitDotState(out, Integer.toString(startArc.target), stateShape,
+ fst.isExpandedTarget(startArc) ? expandedNodeColor : null,
+ "");
+ out.write(" initial -> " + startArc.target + "\n");
+
+ final T NO_OUTPUT = fst.outputs.getNoOutput();
+ int level = 0;
+
+ while (!nextLevelQueue.isEmpty()) {
+ // we could double buffer here, but it doesn't matter probably.
+ thisLevelQueue.addAll(nextLevelQueue);
+ nextLevelQueue.clear();
+
+ level++;
+ out.write("\n // Transitions and states at level: " + level + "\n");
+ while (!thisLevelQueue.isEmpty()) {
+ final FST.Arc<T> arc = thisLevelQueue.remove(thisLevelQueue.size() - 1);
+
+ if (fst.targetHasArcs(arc)) {
+ // scan all arcs
+ final int node = arc.target;
+ fst.readFirstTargetArc(arc, arc);
+
+ while (true) {
+ // Emit the unseen state and add it to the queue for the next level.
+ if (arc.target >= 0 && !seen.get(arc.target)) {
+ final boolean isExpanded = fst.isExpandedTarget(arc);
+ emitDotState(out, Integer.toString(arc.target), stateShape,
+ isExpanded ? expandedNodeColor : null,
+ labelStates ? Integer.toString(arc.target) : "");
+ seen.set(arc.target);
+ nextLevelQueue.add(new FST.Arc<T>().copyFrom(arc));
+ sameLevelStates.add(arc.target);
+ }
+
+ String outs;
+ if (arc.output != NO_OUTPUT) {
+ outs = "/" + fst.outputs.outputToString(arc.output);
+ } else {
+ outs = "";
+ }
+
+ final String cl;
+ if (arc.label == FST.END_LABEL) {
+ cl = "~";
+ } else {
+ cl = printableLabel(arc.label);
+ }
+
+ out.write(" " + node + " -> " + arc.target + " [label=\"" + cl + outs + "\"]\n");
+
+ // Break the loop if we're on the last arc of this state.
+ if (arc.isLast()) {
+ break;
+ }
+ fst.readNextArc(arc);
+ }
+ }
+ }
+
+ // Emit state ranking information.
+ if (sameRank && sameLevelStates.size() > 1) {
+ out.write(" {rank=same; ");
+ for (int state : sameLevelStates) {
+ out.write(state + "; ");
+ }
+ out.write(" }\n");
+ }
+ sameLevelStates.clear();
+ }
+
+ // Emit terminating state (always there anyway).
+ out.write(" -1 [style=filled, color=black, shape=circle, label=\"\"]\n\n");
+ out.write(" {rank=sink; -1 }\n");
+
+ out.write("}\n");
+ out.flush();
+ }
+
+ /**
+ * Emit a single state in the <code>dot</code> language.
+ */
+ private static void emitDotState(Writer out, String name, String shape,
+ String color, String label) throws IOException {
+ out.write(" " + name
+ + " ["
+ + (shape != null ? "shape=" + shape : "") + " "
+ + (color != null ? "color=" + color : "") + " "
+ + (label != null ? "label=\"" + label + "\"" : "label=\"\"") + " "
+ + "]\n");
+ }
+
+ /**
+ * Ensures an arc's label is indeed printable (dot uses US-ASCII).
+ */
+ private static String printableLabel(int label) {
+ if (label >= 0x20 && label <= 0x7d) {
+ return Character.toString((char) label);
+ } else {
+ return "0x" + Integer.toHexString(label);
+ }
+ }
+}
fnp / pylucene.git / blobdiff