org.elasticsearch.common.io.FileChannelInputStream Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.io;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
/**
* @author kimchy (shay.banon)
*/
public class FileChannelInputStream extends InputStream {
private final FileChannel channel;
private long position;
private long length;
private ByteBuffer bb = null;
private byte[] bs = null; // Invoker's previous array
private byte[] b1 = null;
/**
* @param channel The channel to read from
* @param position The position to start reading from
* @param length The length to read
*/
public FileChannelInputStream(FileChannel channel, long position, long length) {
this.channel = channel;
this.position = position;
this.length = position + length; // easier to work with total length
}
@Override public int read() throws IOException {
if (b1 == null) {
b1 = new byte[1];
}
int n = read(b1);
if (n == 1) {
return b1[0] & 0xff;
}
return -1;
}
@Override public int read(byte[] bs, int off, int len) throws IOException {
if (len == 0) {
return 0;
}
if ((length - position) < len) {
len = (int) (length - position);
}
if (len == 0) {
return -1;
}
ByteBuffer bb = ((this.bs == bs) ? this.bb : ByteBuffer.wrap(bs));
bb.limit(Math.min(off + len, bb.capacity()));
bb.position(off);
this.bb = bb;
this.bs = bs;
int read = channel.read(bb, position);
if (read > 0) {
position += read;
}
return read;
}
}