/**
* 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.
*/
package org.apache.mahout.cf.taste.impl.common;
import java.io.Serializable;
/** A simplified and streamlined version of {@link java.util.BitSet}. */
final class BitSet implements Serializable, Cloneable {
private final long[] bits;
BitSet(int numBits) {
int numLongs = numBits >>> 6;
if ((numBits & 0x3F) != 0) {
numLongs++;
}
bits = new long[numLongs];
}
private BitSet(long[] bits) {
this.bits = bits;
}
boolean get(int index) {
// skipping range check for speed
return (bits[index >>> 6] & 1L << (index & 0x3F)) != 0L;
}
void set(int index) {
// skipping range check for speed
bits[index >>> 6] |= 1L << (index & 0x3F);
}
void clear(int index) {
// skipping range check for speed
bits[index >>> 6] &= ~(1L << (index & 0x3F));
}
void clear() {
int length = bits.length;
for (int i = 0; i < length; i++) {
bits[i] = 0L;
}
}
@Override
public BitSet clone() {
return new BitSet(bits);
}
@Override
public String toString() {
StringBuilder result = new StringBuilder(64 * bits.length);
for (long l : bits) {
for (int j = 0; j < 64; j++) {
result.append((l & 1L << j) == 0 ? '0' : '1');
}
result.append(' ');
}
return result.toString();
}
}