org.apache.hadoop.hive.ql.udf.generic.GenericUDFLpad 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.generic;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.io.Text;
/**
* UDFLpad.
*
*/
@Description(name = "lpad",
value = "_FUNC_(str, len, pad) - Returns str, left-padded with pad to a length of len",
extended = "If str is longer than len, the return value is shortened to "
+ "len characters.\n"
+ "Example:\n"
+ " > SELECT _FUNC_('hi', 5, '??') FROM src LIMIT 1;\n"
+ " '???hi'"
+ " > SELECT _FUNC_('hi', 1, '??') FROM src LIMIT 1;\n" + " 'h'")
public class GenericUDFLpad extends GenericUDFBasePad {
public GenericUDFLpad() {
super("lpad");
}
@Override
protected void performOp(byte[] data, byte[] txt, byte[] padTxt, int len, Text str, Text pad) {
// The length of the padding needed
int pos = Math.max(len - str.getLength(), 0);
// Copy the padding
for (int i = 0; i < pos; i += pad.getLength()) {
for (int j = 0; j < pad.getLength() && j < pos - i; j++) {
data[i + j] = padTxt[j];
}
}
// Copy the text
for (int i = 0; pos + i < len && i < str.getLength(); i++) {
data[pos + i] = txt[i];
}
}
}