/*
 * 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.hbase.filter;

import java.nio.ByteBuffer;

import org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException;

import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.shaded.protobuf.generated.ComparatorProtos;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.hadoop.hbase.util.Bytes;


/**
 * A long comparator which numerical compares against the specified byte array
 */
@InterfaceAudience.Public
public class LongComparator extends ByteArrayComparable {
  private long longValue;

  public LongComparator(long value) {
    super(Bytes.toBytes(value));
    this.longValue = value;
  }

  @Override
  public int compareTo(byte[] value, int offset, int length) {
    long that = Bytes.toLong(value, offset, length);
    return Long.compare(longValue, that);
  }

  @Override
  public int compareTo(ByteBuffer value, int offset, int length) {
    long that = ByteBufferUtils.toLong(value, offset);
    return Long.compare(longValue, that);
  }

    /**
     * @return The comparator serialized using pb
     */
    @Override
    public byte [] toByteArray() {
        ComparatorProtos.LongComparator.Builder builder =
                ComparatorProtos.LongComparator.newBuilder();
        builder.setComparable(ProtobufUtil.toByteArrayComparable(this.value));
        return builder.build().toByteArray();
    }

    /**
     * @param pbBytes A pb serialized {@link BinaryComparator} instance
     * @return An instance of {@link BinaryComparator} made from <code>bytes</code>
     * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
     * @see #toByteArray
     */
    public static LongComparator parseFrom(final byte [] pbBytes)
            throws DeserializationException {
        ComparatorProtos.LongComparator proto;
        try {
            proto = ComparatorProtos.LongComparator.parseFrom(pbBytes);
        } catch (InvalidProtocolBufferException e) {
            throw new DeserializationException(e);
        }
        return new LongComparator(Bytes.toLong(proto.getComparable().getValue().toByteArray()));
    }

    /**
     * @param other
     * @return true if and only if the fields of the comparator that are serialized
     * are equal to the corresponding fields in other.  Used for testing.
     */
    boolean areSerializedFieldsEqual(LongComparator other) {
        if (other == this) return true;
        return super.areSerializedFieldsEqual(other);
    }
}