org.apache.activemq.artemis.utils.InflaterReader 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.activemq.artemis.utils;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
/**
* InflaterReader
* It takes a compressed input stream and decompressed it as it is being read.
* Not for concurrent use.
*/
public class InflaterReader extends InputStream {
private Inflater inflater = new Inflater();
private InputStream input;
private byte[] readBuffer;
private int pointer;
private int length;
public InflaterReader(InputStream input) {
this(input, 1024);
}
public InflaterReader(InputStream input, int bufferSize) {
this.input = input;
this.readBuffer = new byte[bufferSize];
this.pointer = -1;
}
@Override
public int read() throws IOException {
if (pointer == -1) {
try {
length = doRead(readBuffer, 0, readBuffer.length);
if (length == 0) {
return -1;
}
pointer = 0;
} catch (DataFormatException e) {
IOException e2 = new IOException(e.getMessage());
e2.initCause(e);
throw e2;
}
}
int value = readBuffer[pointer] & 0xFF;
pointer++;
if (pointer == length) {
pointer = -1;
}
return value;
}
/*
* feed inflater more bytes in order to get some
* decompressed output.
* returns number of bytes actually got
*/
private int doRead(byte[] buf, int offset, int len) throws DataFormatException, IOException {
int read = 0;
int n;
byte[] inputBuffer = new byte[len];
while (len > 0) {
n = inflater.inflate(buf, offset, len);
if (n == 0) {
if (inflater.finished()) {
break;
} else if (inflater.needsInput()) {
//feeding
int m = input.read(inputBuffer);
if (m == -1) {
//it shouldn't be here, throw exception
throw new DataFormatException("Input is over while inflater still expecting data");
} else {
//feed the data in
inflater.setInput(inputBuffer, 0, m);
n = inflater.inflate(buf, offset, len);
if (n > 0) {
read += n;
offset += n;
len -= n;
}
}
} else {
//it shouldn't be here, throw
throw new DataFormatException("Inflater is neither finished nor needing input.");
}
} else {
read += n;
offset += n;
len -= n;
}
}
return read;
}
}