pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / facet / src / java / org / apache / lucene / util / encoding / NOnesIntDecoder.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/encoding/NOnesIntDecoder.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/encoding/NOnesIntDecoder.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/encoding/NOnesIntDecoder.java
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+package org.apache.lucene.util.encoding;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * 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.
+ */
+
+/**
+ * Decodes data which was encoded by {@link NOnesIntEncoder}. Uses a
+ * {@link FourFlagsIntDecoder} to perform the actual encoding and translates the
+ * values back as described in {@link NOnesIntEncoder}.
+ * 
+ * @see NOnesIntEncoder
+ * @lucene.experimental
+ */
+public class NOnesIntDecoder extends FourFlagsIntDecoder {
+
+  /** Number of consecutive '1's to generate upon decoding a '2'. */
+  private int n;
+
+  private int onesCounter;
+
+  /**
+   * Constructs a decoder with a given N (Number of consecutive '1's which are
+   * translated into a single target value '2'.
+   */
+  public NOnesIntDecoder(int n) {
+    this.n = n;
+  }
+
+  @Override
+  public long decode() throws IOException {
+    // If we read '2', we should return n '1's.
+    if (onesCounter > 0) {
+      --onesCounter;
+      return 1;
+    }
+
+    long decode = super.decode();
+    if (decode == 1) {
+      return 1;
+    }
+    if (decode == 2) {
+      onesCounter = n - 1;
+      return 1;
+    }
+    if (decode == 3) {
+      return 2;
+    }
+    return decode == EOS ? EOS : decode - 1;
+  }
+
+  @Override
+  public void reInit(InputStream in) {
+    super.reInit(in);
+    onesCounter = 0;
+  }
+
+  @Override
+  public String toString() {
+    return "NOnes (" + n + ") (" + super.toString() + ")";
+  }
+
+}