1 files changed, 87 insertions, 0 deletions

diff --git a/src/core/Util/DocIdBitSet.cs b/src/core/Util/DocIdBitSet.cs
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+++ b/src/core/Util/DocIdBitSet.cs
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+/* 
+ * 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.
+ */
+
+using System;
+using System.Collections;
+using Lucene.Net.Support;
+using DocIdSet = Lucene.Net.Search.DocIdSet;
+using DocIdSetIterator = Lucene.Net.Search.DocIdSetIterator;
+
+namespace Lucene.Net.Util
+{
+	/// <summary>Simple DocIdSet and DocIdSetIterator backed by a BitSet </summary>
+	public class DocIdBitSet:DocIdSet
+	{
+		private System.Collections.BitArray bitSet;
+		
+		public DocIdBitSet(System.Collections.BitArray bitSet)
+		{
+			this.bitSet = bitSet;
+		}
+		
+		public override DocIdSetIterator Iterator()
+		{
+			return new DocIdBitSetIterator(bitSet);
+		}
+
+	    /// <summary>This DocIdSet implementation is cacheable.</summary>
+	    public override bool IsCacheable
+	    {
+	        get { return true; }
+	    }
+
+	    /// <summary> Returns the underlying BitSet. </summary>
+	    public virtual BitArray BitSet
+	    {
+	        get { return this.bitSet; }
+	    }
+
+	    private class DocIdBitSetIterator:DocIdSetIterator
+		{
+			private int docId;
+			private System.Collections.BitArray bitSet;
+			
+			internal DocIdBitSetIterator(System.Collections.BitArray bitSet)
+			{
+				this.bitSet = bitSet;
+				this.docId = - 1;
+			}
+			
+			public override int DocID()
+			{
+				return docId;
+			}
+			
+			public override int NextDoc()
+			{
+				// (docId + 1) on next line requires -1 initial value for docNr:
+				int d = BitSetSupport.NextSetBit(bitSet, docId + 1);
+				// -1 returned by BitSet.nextSetBit() when exhausted
+				docId = d == - 1?NO_MORE_DOCS:d;
+				return docId;
+			}
+			
+			public override int Advance(int target)
+			{
+				int d = BitSetSupport.NextSetBit(bitSet, target);
+				// -1 returned by BitSet.nextSetBit() when exhausted
+				docId = d == - 1?NO_MORE_DOCS:d;
+				return docId;
+			}
+		}
+	}
+}
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