pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/encoding/SimpleIntDecoder.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/encoding/SimpleIntDecoder.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/SimpleIntDecoder.java
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+package org.apache.lucene.util.encoding;
+
+import java.io.IOException;
+import java.io.StreamCorruptedException;
+
+/**
+ * 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.
+ */
+
+/**
+ * A simple stream decoder which can decode values encoded with
+ * {@link SimpleIntEncoder}.
+ * 
+ * @lucene.experimental
+ */
+public class SimpleIntDecoder extends IntDecoder {
+
+  /**
+   * reusable buffer - allocated only once as this is not a thread-safe object
+   */
+  private byte[] buffer = new byte[4];
+
+  @Override
+  public long decode() throws IOException {
+
+    // we need exactly 4 bytes to decode an int in this decoder impl, otherwise, throw an exception
+    int offset = 0;
+    while (offset < 4) {
+      int nRead = in.read(buffer, offset, 4 - offset);
+      if (nRead == -1) {
+        if (offset > 0) {
+          throw new StreamCorruptedException(
+              "Need 4 bytes for decoding an int, got only " + offset);
+        }
+        return EOS;
+      }
+      offset += nRead;
+    }
+
+    int v = buffer[3] & 0xff;
+    v |= (buffer[2] << 8) & 0xff00;
+    v |= (buffer[1] << 16) & 0xff0000;
+    v |= (buffer[0] << 24) & 0xff000000;
+
+    return v;
+  }
+
+  @Override
+  public String toString() {
+    return "Simple";
+  }
+
+}