pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / index / DefaultSkipListReader.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/DefaultSkipListReader.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/DefaultSkipListReader.java
new file mode 100644 (file)
index 0000000..3c6e856
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/DefaultSkipListReader.java
@@ -0,0 +1,117 @@
+package org.apache.lucene.index;
+
+/**
+ * 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.IOException;
+import java.util.Arrays;
+
+import org.apache.lucene.store.IndexInput;
+
+/**
+ * Implements the skip list reader for the default posting list format
+ * that stores positions and payloads.
+ *
+ */
+class DefaultSkipListReader extends MultiLevelSkipListReader {
+  private boolean currentFieldStoresPayloads;
+  private long freqPointer[];
+  private long proxPointer[];
+  private int payloadLength[];
+  
+  private long lastFreqPointer;
+  private long lastProxPointer;
+  private int lastPayloadLength;
+                           
+
+  DefaultSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval) {
+    super(skipStream, maxSkipLevels, skipInterval);
+    freqPointer = new long[maxSkipLevels];
+    proxPointer = new long[maxSkipLevels];
+    payloadLength = new int[maxSkipLevels];
+  }
+  
+  void init(long skipPointer, long freqBasePointer, long proxBasePointer, int df, boolean storesPayloads) {
+    super.init(skipPointer, df);
+    this.currentFieldStoresPayloads = storesPayloads;
+    lastFreqPointer = freqBasePointer;
+    lastProxPointer = proxBasePointer;
+
+    Arrays.fill(freqPointer, freqBasePointer);
+    Arrays.fill(proxPointer, proxBasePointer);
+    Arrays.fill(payloadLength, 0);
+  }
+
+  /** Returns the freq pointer of the doc to which the last call of 
+   * {@link MultiLevelSkipListReader#skipTo(int)} has skipped.  */
+  long getFreqPointer() {
+    return lastFreqPointer;
+  }
+
+  /** Returns the prox pointer of the doc to which the last call of 
+   * {@link MultiLevelSkipListReader#skipTo(int)} has skipped.  */
+  long getProxPointer() {
+    return lastProxPointer;
+  }
+  
+  /** Returns the payload length of the payload stored just before 
+   * the doc to which the last call of {@link MultiLevelSkipListReader#skipTo(int)} 
+   * has skipped.  */
+  int getPayloadLength() {
+    return lastPayloadLength;
+  }
+  
+  @Override
+  protected void seekChild(int level) throws IOException {
+    super.seekChild(level);
+    freqPointer[level] = lastFreqPointer;
+    proxPointer[level] = lastProxPointer;
+    payloadLength[level] = lastPayloadLength;
+  }
+  
+  @Override
+  protected void setLastSkipData(int level) {
+    super.setLastSkipData(level);
+    lastFreqPointer = freqPointer[level];
+    lastProxPointer = proxPointer[level];
+    lastPayloadLength = payloadLength[level];
+  }
+
+
+  @Override
+  protected int readSkipData(int level, IndexInput skipStream) throws IOException {
+    int delta;
+    if (currentFieldStoresPayloads) {
+      // the current field stores payloads.
+      // if the doc delta is odd then we have
+      // to read the current payload length
+      // because it differs from the length of the
+      // previous payload
+      delta = skipStream.readVInt();
+      if ((delta & 1) != 0) {
+        payloadLength[level] = skipStream.readVInt();
+      }
+      delta >>>= 1;
+    } else {
+      delta = skipStream.readVInt();
+    }
+    freqPointer[level] += skipStream.readVInt();
+    proxPointer[level] += skipStream.readVInt();
+    
+    return delta;
+  }
+}