org.apache.hadoop.hive.ql.udf.UDFCrc32 Maven / Gradle / Ivy
/*
* 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.hive.ql.udf;
import java.util.zip.CRC32;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
/**
* UDFCrc32.
*
*/
@Description(name = "crc32",
value = "_FUNC_(str or bin) - Computes a cyclic redundancy check value "
+ "for string or binary argument and returns bigint value.",
extended = "Example:\n"
+ " > SELECT _FUNC_('ABC');\n"
+ " 2743272264\n"
+ " > SELECT _FUNC_(binary('ABC'));\n"
+ " 2743272264")
public class UDFCrc32 extends UDF {
private final LongWritable result = new LongWritable();
private final CRC32 crc32 = new CRC32();
/**
* CRC32 for string
*/
public LongWritable evaluate(Text n) {
if (n == null) {
return null;
}
crc32.reset();
crc32.update(n.getBytes(), 0, n.getLength());
result.set(crc32.getValue());
return result;
}
/**
* CRC32 for binary
*/
public LongWritable evaluate(BytesWritable b) {
if (b == null) {
return null;
}
crc32.reset();
crc32.update(b.getBytes(), 0, b.getLength());
result.set(crc32.getValue());
return result;
}
}