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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.
*
*/
namespace Lucene.Net.Support
{
/// <summary>
/// This class provides supporting methods of java.util.BitSet
/// that are not present in System.Collections.BitArray.
/// </summary>
public class BitSetSupport
{
/// <summary>
/// Returns the next set bit at or after index, or -1 if no such bit exists.
/// </summary>
/// <param name="bitArray"></param>
/// <param name="index">the index of bit array at which to start checking</param>
/// <returns>the next set bit or -1</returns>
public static int NextSetBit(System.Collections.BitArray bitArray, int index)
{
while (index < bitArray.Length)
{
// if index bit is set, return it
// otherwise check next index bit
if (bitArray.Get(index))
return index;
else
index++;
}
// if no bits are set at or after index, return -1
return -1;
}
/// <summary>
/// Returns the next un-set bit at or after index, or -1 if no such bit exists.
/// </summary>
/// <param name="bitArray"></param>
/// <param name="index">the index of bit array at which to start checking</param>
/// <returns>the next set bit or -1</returns>
public static int NextClearBit(System.Collections.BitArray bitArray, int index)
{
while (index < bitArray.Length)
{
// if index bit is not set, return it
// otherwise check next index bit
if (!bitArray.Get(index))
return index;
else
index++;
}
// if no bits are set at or after index, return -1
return -1;
}
/// <summary>
/// Returns the number of bits set to true in this BitSet.
/// </summary>
/// <param name="bits">The BitArray object.</param>
/// <returns>The number of bits set to true in this BitSet.</returns>
public static int Cardinality(System.Collections.BitArray bits)
{
int count = 0;
for (int i = 0; i < bits.Count; i++)
{
if (bits[i])
count++;
}
return count;
}
}
}
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