pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / analysis / BaseCharFilter.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/BaseCharFilter.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/BaseCharFilter.java
new file mode 100644 (file)
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--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/BaseCharFilter.java
@@ -0,0 +1,85 @@
+/**
+ * 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.
+ */
+
+package org.apache.lucene.analysis;
+
+import org.apache.lucene.util.ArrayUtil;
+
+/**
+ * Base utility class for implementing a {@link CharFilter}.
+ * You subclass this, and then record mappings by calling
+ * {@link #addOffCorrectMap}, and then invoke the correct
+ * method to correct an offset.
+ */
+public abstract class BaseCharFilter extends CharFilter {
+
+  private int offsets[];
+  private int diffs[];
+  private int size = 0;
+  
+  public BaseCharFilter(CharStream in) {
+    super(in);
+  }
+
+  /** Retrieve the corrected offset. */
+  @Override
+  protected int correct(int currentOff) {
+    if (offsets == null || currentOff < offsets[0]) {
+      return currentOff;
+    }
+    
+    int hi = size - 1;
+    if(currentOff >= offsets[hi])
+      return currentOff + diffs[hi];
+
+    int lo = 0;
+    int mid = -1;
+    
+    while (hi >= lo) {
+      mid = (lo + hi) >>> 1;
+      if (currentOff < offsets[mid])
+        hi = mid - 1;
+      else if (currentOff > offsets[mid])
+        lo = mid + 1;
+      else
+        return currentOff + diffs[mid];
+    }
+
+    if (currentOff < offsets[mid])
+      return mid == 0 ? currentOff : currentOff + diffs[mid-1];
+    else
+      return currentOff + diffs[mid];
+  }
+  
+  protected int getLastCumulativeDiff() {
+    return offsets == null ?
+      0 : diffs[size-1];
+  }
+
+  protected void addOffCorrectMap(int off, int cumulativeDiff) {
+    if (offsets == null) {
+      offsets = new int[64];
+      diffs = new int[64];
+    } else if (size == offsets.length) {
+      offsets = ArrayUtil.grow(offsets);
+      diffs = ArrayUtil.grow(diffs);
+    }
+    
+    offsets[size] = off;
+    diffs[size++] = cumulativeDiff; 
+  }
+}