/*
 * 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
 *
 *   https://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.accumulo.core.iteratorsImpl.conf;

import org.apache.accumulo.core.data.ByteSequence;
import org.apache.accumulo.core.data.Key;
import org.apache.hadoop.io.Text;

public class ColumnUtil {
  private static int hash(byte[] bytes, int offset, int len) {
    int hash = 1;
    int end = offset + len;

    for (int i = offset; i < end; i++) {
      hash = (31 * hash) + bytes[i];
    }

    return hash;
  }

  private static int hash(ByteSequence bs) {
    return hash(bs.getBackingArray(), bs.offset(), bs.length());
  }

  public static class ColFamHashKey {
    final Text columnFamily;

    Key key;

    private int hashCode;

    ColFamHashKey() {
      columnFamily = null;
    }

    ColFamHashKey(Text cf) {
      columnFamily = cf;
      hashCode = hash(columnFamily.getBytes(), 0, columnFamily.getLength());
    }

    void set(Key key) {
      this.key = key;
      hashCode = hash(key.getColumnFamilyData());
    }

    @Override
    public int hashCode() {
      return hashCode;
    }

    @Override
    public boolean equals(Object o) {
      if (o instanceof ColFamHashKey) {
        return equals((ColFamHashKey) o);
      }
      return false;
    }

    public boolean equals(ColFamHashKey ohk) {
      if (columnFamily == null) {
        return key.compareColumnFamily(ohk.columnFamily) == 0;
      }
      return ohk.key.compareColumnFamily(columnFamily) == 0;
    }
  }

  public static class ColHashKey {
    final Text columnFamily;
    final Text columnQualifier;

    Key key;

    private int hashValue;

    ColHashKey() {
      columnFamily = null;
      columnQualifier = null;
    }

    ColHashKey(Text cf, Text cq) {
      columnFamily = cf;
      columnQualifier = cq;
      hashValue = hash(columnFamily.getBytes(), 0, columnFamily.getLength())
          + hash(columnQualifier.getBytes(), 0, columnQualifier.getLength());
    }

    void set(Key key) {
      this.key = key;
      hashValue = hash(key.getColumnFamilyData()) + hash(key.getColumnQualifierData());
    }

    @Override
    public int hashCode() {
      return hashValue;
    }

    @Override
    public boolean equals(Object o) {
      if (o instanceof ColHashKey) {
        return equals((ColHashKey) o);
      }
      return false;
    }

    public boolean equals(ColHashKey ohk) {
      if (columnFamily == null) {
        return key.compareColumnFamily(ohk.columnFamily) == 0
            && key.compareColumnQualifier(ohk.columnQualifier) == 0;
      }
      return ohk.key.compareColumnFamily(columnFamily) == 0
          && ohk.key.compareColumnQualifier(columnQualifier) == 0;
    }
  }
}
