/**
* 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.hadoop.hdfs.util;
import java.io.Serializable;
/**
* Bit format in a long.
*/
public class LongBitFormat implements Serializable {
private static final long serialVersionUID = 1L;
private final String NAME;
/** Bit offset */
private final int OFFSET;
/** Bit length */
private final int LENGTH;
/** Minimum value */
private final long MIN;
/** Maximum value */
private final long MAX;
/** Bit mask */
private final long MASK;
public LongBitFormat(String name, LongBitFormat previous, int length, long min) {
NAME = name;
OFFSET = previous == null? 0: previous.OFFSET + previous.LENGTH;
LENGTH = length;
MIN = min;
MAX = ((-1L) >>> (64 - LENGTH));
MASK = MAX << OFFSET;
}
/** Retrieve the value from the record. */
public long retrieve(long record) {
return (record & MASK) >>> OFFSET;
}
/** Combine the value to the record. */
public long combine(long value, long record) {
if (value < MIN) {
throw new IllegalArgumentException(
"Illagal value: " + NAME + " = " + value + " < MIN = " + MIN);
}
if (value > MAX) {
throw new IllegalArgumentException(
"Illagal value: " + NAME + " = " + value + " > MAX = " + MAX);
}
return (record & ~MASK) | (value << OFFSET);
}
public long getMin() {
return MIN;
}
}