pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/ByteSliceReader.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/ByteSliceReader.java
new file mode 100644 (file)
index 0000000..5b8e388
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/index/ByteSliceReader.java
@@ -0,0 +1,149 @@
+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 org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import java.io.IOException;
+
+/* IndexInput that knows how to read the byte slices written
+ * by Posting and PostingVector.  We read the bytes in
+ * each slice until we hit the end of that slice at which
+ * point we read the forwarding address of the next slice
+ * and then jump to it.*/
+final class ByteSliceReader extends IndexInput {
+  ByteBlockPool pool;
+  int bufferUpto;
+  byte[] buffer;
+  public int upto;
+  int limit;
+  int level;
+  public int bufferOffset;
+
+  public int endIndex;
+
+  public void init(ByteBlockPool pool, int startIndex, int endIndex) {
+
+    assert endIndex-startIndex >= 0;
+    assert startIndex >= 0;
+    assert endIndex >= 0;
+
+    this.pool = pool;
+    this.endIndex = endIndex;
+
+    level = 0;
+    bufferUpto = startIndex / DocumentsWriter.BYTE_BLOCK_SIZE;
+    bufferOffset = bufferUpto * DocumentsWriter.BYTE_BLOCK_SIZE;
+    buffer = pool.buffers[bufferUpto];
+    upto = startIndex & DocumentsWriter.BYTE_BLOCK_MASK;
+
+    final int firstSize = ByteBlockPool.levelSizeArray[0];
+
+    if (startIndex+firstSize >= endIndex) {
+      // There is only this one slice to read
+      limit = endIndex & DocumentsWriter.BYTE_BLOCK_MASK;
+    } else
+      limit = upto+firstSize-4;
+  }
+
+  public boolean eof() {
+    assert upto + bufferOffset <= endIndex;
+    return upto + bufferOffset == endIndex;
+  }
+
+  @Override
+  public byte readByte() {
+    assert !eof();
+    assert upto <= limit;
+    if (upto == limit)
+      nextSlice();
+    return buffer[upto++];
+  }
+
+  public long writeTo(IndexOutput out) throws IOException {
+    long size = 0;
+    while(true) {
+      if (limit + bufferOffset == endIndex) {
+        assert endIndex - bufferOffset >= upto;
+        out.writeBytes(buffer, upto, limit-upto);
+        size += limit-upto;
+        break;
+      } else {
+        out.writeBytes(buffer, upto, limit-upto);
+        size += limit-upto;
+        nextSlice();
+      }
+    }
+
+    return size;
+  }
+
+  public void nextSlice() {
+
+    // Skip to our next slice
+    final int nextIndex = ((buffer[limit]&0xff)<<24) + ((buffer[1+limit]&0xff)<<16) + ((buffer[2+limit]&0xff)<<8) + (buffer[3+limit]&0xff);
+
+    level = ByteBlockPool.nextLevelArray[level];
+    final int newSize = ByteBlockPool.levelSizeArray[level];
+
+    bufferUpto = nextIndex / DocumentsWriter.BYTE_BLOCK_SIZE;
+    bufferOffset = bufferUpto * DocumentsWriter.BYTE_BLOCK_SIZE;
+
+    buffer = pool.buffers[bufferUpto];
+    upto = nextIndex & DocumentsWriter.BYTE_BLOCK_MASK;
+
+    if (nextIndex + newSize >= endIndex) {
+      // We are advancing to the final slice
+      assert endIndex - nextIndex > 0;
+      limit = endIndex - bufferOffset;
+    } else {
+      // This is not the final slice (subtract 4 for the
+      // forwarding address at the end of this new slice)
+      limit = upto+newSize-4;
+    }
+  }
+
+  @Override
+  public void readBytes(byte[] b, int offset, int len) {
+    while(len > 0) {
+      final int numLeft = limit-upto;
+      if (numLeft < len) {
+        // Read entire slice
+        System.arraycopy(buffer, upto, b, offset, numLeft);
+        offset += numLeft;
+        len -= numLeft;
+        nextSlice();
+      } else {
+        // This slice is the last one
+        System.arraycopy(buffer, upto, b, offset, len);
+        upto += len;
+        break;
+      }
+    }
+  }
+
+  @Override
+  public long getFilePointer() {throw new RuntimeException("not implemented");}
+  @Override
+  public long length() {throw new RuntimeException("not implemented");}
+  @Override
+  public void seek(long pos) {throw new RuntimeException("not implemented");}
+  @Override
+  public void close() {throw new RuntimeException("not implemented");}
+}
+