flink-core/src/main/java/org/apache/flink/api/common/typeutils/base/InstantComparator.java

/*
 * 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.flink.api.common.typeutils.base;

import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.MemorySegment;

import java.io.IOException;
import java.time.Instant;

/**
 * Comparator for comparing Java Instant.
 */
@Internal
public final class InstantComparator extends BasicTypeComparator<Instant>{

	private static final long serialVersionUID = 1L;
	private static final long SECONDS_MIN_VALUE = Instant.MIN.getEpochSecond();

	public InstantComparator(boolean ascending) {
		super(ascending);
	}

	@Override
	public int compareSerialized(DataInputView firstSource, DataInputView secondSource) throws IOException {
		final long lSeconds = firstSource.readLong();
		final long rSeconds = secondSource.readLong();
		final int comp;
		if (lSeconds == rSeconds) {
			final int lNanos = firstSource.readInt();
			final int rNanos = secondSource.readInt();
			comp = (lNanos < rNanos ? -1 : (lNanos == rNanos ? 0 : 1));
		} else {
			comp = lSeconds < rSeconds ? -1 : 1;
		}
		return ascendingComparison ? comp : -comp;
	}

	@Override
	public boolean supportsNormalizedKey() {
		return true;
	}

	@Override
	public int getNormalizeKeyLen() {
		return InstantSerializer.SECONDS_BYTES + InstantSerializer.NANOS_BYTES;
	}

	@Override
	public boolean isNormalizedKeyPrefixOnly(int keyBytes) {
		return keyBytes < getNormalizeKeyLen();
	}

	@Override
	public void putNormalizedKey(Instant record, MemorySegment target, int offset, int numBytes) {
		final int secondsBytes = InstantSerializer.SECONDS_BYTES;
		final long normalizedSeconds = record.getEpochSecond() - SECONDS_MIN_VALUE;
		if (numBytes >= secondsBytes) {
			target.putLongBigEndian(offset, normalizedSeconds);
			offset += secondsBytes;
			numBytes -= secondsBytes;

			final int nanosBytes = InstantSerializer.NANOS_BYTES;
			if (numBytes >= nanosBytes) {
				target.putIntBigEndian(offset, record.getNano());
				offset += nanosBytes;
				numBytes -= nanosBytes;
				for (int i = 0; i < numBytes; i++) {
					target.put(offset + i, (byte) 0);
				}
			} else {
				final int nanos = record.getNano();
				for (int i = 0; i < numBytes;  i++) {
					target.put(offset + i, (byte) (nanos >>> ((3 - i) << 3)));
				}
			}
		} else {
			for (int i = 0; i < numBytes; i++) {
				target.put(offset + i, (byte) (normalizedSeconds >>> ((7 - i) << 3)));
			}
		}
	}

	@Override
	public TypeComparator<Instant> duplicate() {
		return new InstantComparator(ascendingComparison);
	}
}