water.parser.parquet.ParquetInt96TimestampConverter Maven / Gradle / Ivy
/*
* 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 at
*
* Copyright H20.ai Limited
* 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 water.parser.parquet;
import org.apache.parquet.io.api.Binary;
import java.util.concurrent.TimeUnit;
/**
* Class for decoding INT96 encoded parquet timestamp to timestamp millis in GMT.
*
* This class is equivalent of @see org.apache.hadoop.hive.ql.io.parquet.timestamp.NanoTime,
* which produces less intermediate objects during decoding.
*
* This class is a modified version of ParquetTimestampUtils from Presto project.
*/
final class ParquetInt96TimestampConverter {
private static final int JULIAN_EPOCH_OFFSET_DAYS = 2_440_588;
private static final long MILLIS_IN_DAY = TimeUnit.DAYS.toMillis(1);
private static final long NANOS_PER_MILLISECOND = TimeUnit.MILLISECONDS.toNanos(1);
private static final byte BYTES_IN_INT96_TIMESTAMP = 12;
private ParquetInt96TimestampConverter() {
}
/**
* Returns GMT timestamp from binary encoded parquet timestamp (12 bytes - julian date + time of day nanos).
*
* @param timestampBinary INT96 parquet timestamp
* @return timestamp in millis, GMT timezone
*/
public static long getTimestampMillis(Binary timestampBinary) {
if (timestampBinary.length() != BYTES_IN_INT96_TIMESTAMP) {
throw new IllegalArgumentException("Parquet timestamp must be 12 bytes long, actual " + timestampBinary.length());
}
byte[] bytes = timestampBinary.getBytes();
// little endian encoding - bytes are red in inverted order
long timeOfDayNanos = TypeUtils.longFromBytes(bytes[7], bytes[6], bytes[5], bytes[4], bytes[3], bytes[2], bytes[1], bytes[0]);
int julianDay = TypeUtils.intFromBytes(bytes[11], bytes[10], bytes[9], bytes[8]);
return julianDayToMillis(julianDay) + (timeOfDayNanos / NANOS_PER_MILLISECOND);
}
/**
* @param julianDay Day since the beginning of Julian calendar
* @return millis since epoch
*/
private static long julianDayToMillis(int julianDay) {
return (julianDay - JULIAN_EPOCH_OFFSET_DAYS) * MILLIS_IN_DAY;
}
}