/*
* 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.io.compress.zlib;
import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.util.NativeCodeLoader;
/**
* A {@link Decompressor} based on the popular
* zlib compression algorithm.
* http://www.zlib.net/
*
*/
public class ZlibDecompressor implements Decompressor {
private static final int DEFAULT_DIRECT_BUFFER_SIZE = 64*1024;
// HACK - Use this as a global lock in the JNI layer
private static Class clazz = ZlibDecompressor.class;
private long stream;
private CompressionHeader header;
private int directBufferSize;
private Buffer compressedDirectBuf = null;
private int compressedDirectBufOff, compressedDirectBufLen;
private Buffer uncompressedDirectBuf = null;
private byte[] userBuf = null;
private int userBufOff = 0, userBufLen = 0;
private boolean finished;
private boolean needDict;
/**
* The headers to detect from compressed data.
*/
public static enum CompressionHeader {
/**
* No headers/trailers/checksums.
*/
NO_HEADER (-15),
/**
* Default headers/trailers/checksums.
*/
DEFAULT_HEADER (15),
/**
* Simple gzip headers/trailers.
*/
GZIP_FORMAT (31),
/**
* Autodetect gzip/zlib headers/trailers.
*/
AUTODETECT_GZIP_ZLIB (47);
private final int windowBits;
CompressionHeader(int windowBits) {
this.windowBits = windowBits;
}
public int windowBits() {
return windowBits;
}
}
private static boolean nativeZlibLoaded = false;
static {
if (NativeCodeLoader.isNativeCodeLoaded()) {
try {
// Initialize the native library
initIDs();
nativeZlibLoaded = true;
} catch (Throwable t) {
// Ignore failure to load/initialize native-zlib
}
}
}
static boolean isNativeZlibLoaded() {
return nativeZlibLoaded;
}
/**
* Creates a new decompressor.
*/
public ZlibDecompressor(CompressionHeader header, int directBufferSize) {
this.header = header;
this.directBufferSize = directBufferSize;
compressedDirectBuf = ByteBuffer.allocateDirect(directBufferSize);
uncompressedDirectBuf = ByteBuffer.allocateDirect(directBufferSize);
uncompressedDirectBuf.position(directBufferSize);
stream = init(this.header.windowBits());
}
public ZlibDecompressor() {
this(CompressionHeader.DEFAULT_HEADER, DEFAULT_DIRECT_BUFFER_SIZE);
}
public synchronized void setInput(byte[] b, int off, int len) {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
this.userBuf = b;
this.userBufOff = off;
this.userBufLen = len;
setInputFromSavedData();
// Reinitialize zlib's output direct buffer
uncompressedDirectBuf.limit(directBufferSize);
uncompressedDirectBuf.position(directBufferSize);
}
synchronized void setInputFromSavedData() {
compressedDirectBufOff = 0;
compressedDirectBufLen = userBufLen;
if (compressedDirectBufLen > directBufferSize) {
compressedDirectBufLen = directBufferSize;
}
// Reinitialize zlib's input direct buffer
compressedDirectBuf.rewind();
((ByteBuffer)compressedDirectBuf).put(userBuf, userBufOff,
compressedDirectBufLen);
// Note how much data is being fed to zlib
userBufOff += compressedDirectBufLen;
userBufLen -= compressedDirectBufLen;
}
public synchronized void setDictionary(byte[] b, int off, int len) {
if (stream == 0 || b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
setDictionary(stream, b, off, len);
needDict = false;
}
public synchronized boolean needsInput() {
// Consume remaining compressed data?
if (uncompressedDirectBuf.remaining() > 0) {
return false;
}
// Check if zlib has consumed all input
if (compressedDirectBufLen <= 0) {
// Check if we have consumed all user-input
if (userBufLen <= 0) {
return true;
} else {
setInputFromSavedData();
}
}
return false;
}
public synchronized boolean needsDictionary() {
return needDict;
}
public synchronized boolean finished() {
// Check if 'zlib' says it's 'finished' and
// all compressed data has been consumed
return (finished && uncompressedDirectBuf.remaining() == 0);
}
public synchronized int decompress(byte[] b, int off, int len)
throws IOException {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
int n = 0;
// Check if there is uncompressed data
n = uncompressedDirectBuf.remaining();
if (n > 0) {
n = Math.min(n, len);
((ByteBuffer)uncompressedDirectBuf).get(b, off, n);
return n;
}
// Re-initialize the zlib's output direct buffer
uncompressedDirectBuf.rewind();
uncompressedDirectBuf.limit(directBufferSize);
// Decompress data
n = inflateBytesDirect();
uncompressedDirectBuf.limit(n);
// Get at most 'len' bytes
n = Math.min(n, len);
((ByteBuffer)uncompressedDirectBuf).get(b, off, n);
return n;
}
/**
* Returns the total number of uncompressed bytes output so far.
*
* @return the total (non-negative) number of uncompressed bytes output so far
*/
public synchronized long getBytesWritten() {
checkStream();
return getBytesWritten(stream);
}
/**
* Returns the total number of compressed bytes input so far.</p>
*
* @return the total (non-negative) number of compressed bytes input so far
*/
public synchronized long getBytesRead() {
checkStream();
return getBytesRead(stream);
}
/**
* Returns the number of bytes remaining in the input buffers; normally
* called when finished() is true to determine amount of post-gzip-stream
* data.</p>
*
* @return the total (non-negative) number of unprocessed bytes in input
*/
public synchronized int getRemaining() {
checkStream();
return userBufLen + getRemaining(stream); // userBuf + compressedDirectBuf
}
/**
* Resets everything including the input buffers (user and direct).</p>
*/
public synchronized void reset() {
checkStream();
reset(stream);
finished = false;
needDict = false;
compressedDirectBufOff = compressedDirectBufLen = 0;
uncompressedDirectBuf.limit(directBufferSize);
uncompressedDirectBuf.position(directBufferSize);
userBufOff = userBufLen = 0;
}
public synchronized void end() {
if (stream != 0) {
end(stream);
stream = 0;
}
}
protected void finalize() {
end();
}
private void checkStream() {
if (stream == 0)
throw new NullPointerException();
}
private native static void initIDs();
private native static long init(int windowBits);
private native static void setDictionary(long strm, byte[] b, int off,
int len);
private native int inflateBytesDirect();
private native static long getBytesRead(long strm);
private native static long getBytesWritten(long strm);
private native static int getRemaining(long strm);
private native static void reset(long strm);
private native static void end(long strm);
}