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Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.bytes;
import org.apache.lucene.util.BytesRef;
import java.nio.ByteBuffer;
/**
* This is a {@link BytesReference} backed by a {@link ByteBuffer}. The byte buffer can either be a heap or
* direct byte buffer. The reference is composed of the space between the {@link ByteBuffer#position} and
* {@link ByteBuffer#limit} at construction time. If the position or limit of the underlying byte buffer is
* changed, those changes will not be reflected in this reference. However, modifying the limit or position
* of the underlying byte buffer is not recommended as those can be used during {@link ByteBuffer#get()}
* bounds checks. Use {@link ByteBuffer#duplicate()} at creation time if you plan on modifying the markers of
* the underlying byte buffer. Any changes to the underlying data in the byte buffer will be reflected.
*/
public class ByteBufferReference extends BytesReference {
private final ByteBuffer buffer;
private final int offset;
private final int length;
public ByteBufferReference(ByteBuffer buffer) {
this.buffer = buffer;
this.offset = buffer.position();
this.length = buffer.remaining();
}
@Override
public byte get(int index) {
return buffer.get(index + offset);
}
@Override
public int length() {
return length;
}
@Override
public BytesReference slice(int from, int length) {
if (from < 0 || (from + length) > this.length) {
throw new IndexOutOfBoundsException("can't slice a buffer with length [" + this.length + "], with slice parameters from ["
+ from + "], length [" + length + "]");
}
ByteBuffer newByteBuffer = buffer.duplicate();
newByteBuffer.position(offset + from);
newByteBuffer.limit(offset + from + length);
return new ByteBufferReference(newByteBuffer);
}
/**
* This will return a bytes ref composed of the bytes. If this is a direct byte buffer, the bytes will
* have to be copied.
*
* @return the bytes ref
*/
@Override
public BytesRef toBytesRef() {
if (buffer.hasArray()) {
return new BytesRef(buffer.array(), buffer.arrayOffset() + offset, length);
}
final byte[] copy = new byte[length];
buffer.get(copy, offset, length);
return new BytesRef(copy);
}
@Override
public long ramBytesUsed() {
return buffer.capacity();
}
}