/**
* 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.serde2.columnar;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparator;
import org.apache.hadoop.io.WritableFactories;
import org.apache.hadoop.io.WritableFactory;
/**
* <tt>BytesRefWritable</tt> referenced a section of byte array. It can be used
* to avoid unnecessary byte copy.
*/
public class BytesRefWritable implements Writable, Comparable<BytesRefWritable> {
private static final byte[] EMPTY_BYTES = new byte[0];
public static BytesRefWritable ZeroBytesRefWritable = new BytesRefWritable();
int start = 0;
int length = 0;
byte[] bytes = null;
LazyDecompressionCallback lazyDecompressObj;
/**
* Create a zero-size bytes.
*/
public BytesRefWritable() {
this(EMPTY_BYTES);
}
/**
* Create a BytesRefWritable with <tt>length</tt> bytes.
*/
public BytesRefWritable(int length) {
assert length > 0;
this.length = length;
bytes = new byte[this.length];
start = 0;
}
/**
* Create a BytesRefWritable referenced to the given bytes.
*/
public BytesRefWritable(byte[] bytes) {
this.bytes = bytes;
length = bytes.length;
start = 0;
}
/**
* Create a BytesRefWritable referenced to one section of the given bytes. The
* section is determined by argument <tt>offset</tt> and <tt>len</tt>.
*/
public BytesRefWritable(byte[] data, int offset, int len) {
bytes = data;
start = offset;
length = len;
}
/**
* Create a BytesRefWritable referenced to one section of the given bytes. The
* argument <tt>lazyDecompressData</tt> refers to a LazyDecompressionCallback
* object. The arguments <tt>offset</tt> and <tt>len</tt> are referred to
* uncompressed bytes of <tt>lazyDecompressData</tt>. Use <tt>offset</tt> and
* <tt>len</tt> after uncompressing the data.
*/
public BytesRefWritable(LazyDecompressionCallback lazyDecompressData,
int offset, int len) {
lazyDecompressObj = lazyDecompressData;
start = offset;
length = len;
}
private void lazyDecompress() throws IOException {
if (bytes == null && lazyDecompressObj != null) {
bytes = lazyDecompressObj.decompress();
}
}
/**
* Returns a copy of the underlying bytes referenced by this instance.
*
* @return a new copied byte array
* @throws IOException
*/
public byte[] getBytesCopy() throws IOException {
lazyDecompress();
byte[] bb = new byte[length];
System.arraycopy(bytes, start, bb, 0, length);
return bb;
}
/**
* Returns the underlying bytes.
*
* @throws IOException
*/
public byte[] getData() throws IOException {
lazyDecompress();
return bytes;
}
/**
* readFields() will corrupt the array. So use the set method whenever
* possible.
*
* @see #readFields(DataInput)
*/
public void set(byte[] newData, int offset, int len) {
bytes = newData;
start = offset;
length = len;
lazyDecompressObj = null;
}
/**
* readFields() will corrupt the array. So use the set method whenever
* possible.
*
* @see #readFields(DataInput)
*/
public void set(LazyDecompressionCallback newData, int offset, int len) {
bytes = null;
start = offset;
length = len;
lazyDecompressObj = newData;
}
public void writeDataTo(DataOutput out) throws IOException {
lazyDecompress();
out.write(bytes, start, length);
}
/**
* Always reuse the bytes array if length of bytes array is equal or greater
* to the current record, otherwise create a new one. readFields will corrupt
* the array. Please use set() whenever possible.
*
* @see #set(byte[], int, int)
*/
public void readFields(DataInput in) throws IOException {
int len = in.readInt();
if (len > bytes.length) {
bytes = new byte[len];
}
start = 0;
length = len;
in.readFully(bytes, start, length);
}
/** {@inheritDoc} */
public void write(DataOutput out) throws IOException {
lazyDecompress();
out.writeInt(length);
out.write(bytes, start, length);
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return super.hashCode();
}
/** {@inheritDoc} */
@Override
public String toString() {
StringBuilder sb = new StringBuilder(3 * length);
for (int idx = start; idx < length; idx++) {
// if not the first, put a blank separator in
if (idx != 0) {
sb.append(' ');
}
String num = Integer.toHexString(0xff & bytes[idx]);
// if it is only one digit, add a leading 0.
if (num.length() < 2) {
sb.append('0');
}
sb.append(num);
}
return sb.toString();
}
/** {@inheritDoc} */
@Override
public int compareTo(BytesRefWritable other) {
if (other == null) {
throw new IllegalArgumentException("Argument can not be null.");
}
if (this == other) {
return 0;
}
try {
return WritableComparator.compareBytes(getData(), start, getLength(),
other.getData(), other.start, other.getLength());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/** {@inheritDoc} */
@Override
public boolean equals(Object right_obj) {
if (right_obj == null || !(right_obj instanceof BytesRefWritable)) {
return false;
}
return compareTo((BytesRefWritable) right_obj) == 0;
}
static {
WritableFactories.setFactory(BytesRefWritable.class, new WritableFactory() {
@Override
public Writable newInstance() {
return new BytesRefWritable();
}
});
}
public int getLength() {
return length;
}
public int getStart() {
return start;
}
}