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/**
* 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.fs;
import java.io.BufferedInputStream;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* A class optimizes reading from FSInputStream by bufferring
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class BufferedFSInputStream extends BufferedInputStream
implements Seekable, PositionedReadable {
/**
* Creates a BufferedFSInputStream
* with the specified buffer size,
* and saves its argument, the input stream
* in, for later use. An internal
* buffer array of length size
* is created and stored in buf.
*
* @param in the underlying input stream.
* @param size the buffer size.
* @exception IllegalArgumentException if size <= 0.
*/
public BufferedFSInputStream(FSInputStream in, int size) {
super(in, size);
}
public long getPos() throws IOException {
return ((FSInputStream)in).getPos()-(count-pos);
}
public long skip(long n) throws IOException {
if (n <= 0) {
return 0;
}
seek(getPos()+n);
return n;
}
public void seek(long pos) throws IOException {
if( pos<0 ) {
return;
}
// optimize: check if the pos is in the buffer
long end = ((FSInputStream)in).getPos();
long start = end - count;
if( pos>=start && pos