X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/fst/Util.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/fst/Util.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/fst/Util.java
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@@ -0,0 +1,328 @@
+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(&quot;out.dot&quot;);
+   * 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);
+    }
+  }
+}