/*
* Copyright 2009-2013 by The Regents of the University of California
* Licensed 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 from
*
* 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 edu.uci.ics.pregelix.example.data;
import edu.uci.ics.pregelix.api.graph.NormalizedKeyComputer;
import edu.uci.ics.pregelix.api.util.SerDeUtils;
/**
* @author yingyib
*/
public class VLongNormalizedKeyComputer implements NormalizedKeyComputer {
private static final int POSTIVE_LONG_MASK = (3 << 30);
private static final int NON_NEGATIVE_INT_MASK = (2 << 30);
private static final int NEGATIVE_LONG_MASK = (0 << 30);
@Override
public int getNormalizedKey(byte[] bytes, int start, int length) {
try {
long value = SerDeUtils.readVLong(bytes, start, length);
int highValue = (int) (value >> 32);
if (highValue > 0) {
/**
* larger than Integer.MAX
*/
int highNmk = getKey(highValue);
highNmk >>= 2;
highNmk |= POSTIVE_LONG_MASK;
return highNmk;
} else if (highValue == 0) {
/**
* smaller than Integer.MAX but >=0
*/
int lowNmk = (int) value;
lowNmk >>= 2;
lowNmk |= NON_NEGATIVE_INT_MASK;
return lowNmk;
} else {
/**
* less than 0; TODO: have not optimized for that
*/
int highNmk = getKey(highValue);
highNmk >>= 2;
highNmk |= NEGATIVE_LONG_MASK;
return highNmk;
}
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
private int getKey(int value) {
long unsignedFirstValue = (long) value;
int nmk = (int) ((unsignedFirstValue - ((long) Integer.MIN_VALUE)) & 0xffffffffL);
return nmk;
}
}