/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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 io.netty.handler.codec.compression;
import com.jcraft.jzlib.Deflater;
import com.jcraft.jzlib.JZlib;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.channel.ChannelPromiseNotifier;
import io.netty.util.concurrent.EventExecutor;
import io.netty.util.internal.EmptyArrays;
import java.util.concurrent.TimeUnit;
/**
* Compresses a {@link ByteBuf} using the deflate algorithm.
*/
public class JZlibEncoder extends ZlibEncoder {
private final int wrapperOverhead;
private final Deflater z = new Deflater();
private volatile boolean finished;
private volatile ChannelHandlerContext ctx;
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the default wrapper ({@link ZlibWrapper#ZLIB}).
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder() {
this(6);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the default wrapper ({@link ZlibWrapper#ZLIB}).
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(int compressionLevel) {
this(ZlibWrapper.ZLIB, compressionLevel);
}
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified wrapper.
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(ZlibWrapper wrapper) {
this(wrapper, 6);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified wrapper.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
this(wrapper, compressionLevel, 15, 8);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* the specified {@code windowBits}, the specified {@code memLevel}, and
* the specified wrapper.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param windowBits
* The base two logarithm of the size of the history buffer. The
* value should be in the range {@code 9} to {@code 15} inclusive.
* Larger values result in better compression at the expense of
* memory usage. The default value is {@code 15}.
* @param memLevel
* How much memory should be allocated for the internal compression
* state. {@code 1} uses minimum memory and {@code 9} uses maximum
* memory. Larger values result in better and faster compression
* at the expense of memory usage. The default value is {@code 8}
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(ZlibWrapper wrapper, int compressionLevel, int windowBits, int memLevel) {
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException(
"compressionLevel: " + compressionLevel +
" (expected: 0-9)");
}
if (windowBits < 9 || windowBits > 15) {
throw new IllegalArgumentException(
"windowBits: " + windowBits + " (expected: 9-15)");
}
if (memLevel < 1 || memLevel > 9) {
throw new IllegalArgumentException(
"memLevel: " + memLevel + " (expected: 1-9)");
}
if (wrapper == null) {
throw new NullPointerException("wrapper");
}
if (wrapper == ZlibWrapper.ZLIB_OR_NONE) {
throw new IllegalArgumentException(
"wrapper '" + ZlibWrapper.ZLIB_OR_NONE + "' is not " +
"allowed for compression.");
}
int resultCode = z.init(
compressionLevel, windowBits, memLevel,
ZlibUtil.convertWrapperType(wrapper));
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "initialization failure", resultCode);
}
wrapperOverhead = ZlibUtil.wrapperOverhead(wrapper);
}
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(byte[] dictionary) {
this(6, dictionary);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(int compressionLevel, byte[] dictionary) {
this(compressionLevel, 15, 8, dictionary);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* the specified {@code windowBits}, the specified {@code memLevel},
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param windowBits
* The base two logarithm of the size of the history buffer. The
* value should be in the range {@code 9} to {@code 15} inclusive.
* Larger values result in better compression at the expense of
* memory usage. The default value is {@code 15}.
* @param memLevel
* How much memory should be allocated for the internal compression
* state. {@code 1} uses minimum memory and {@code 9} uses maximum
* memory. Larger values result in better and faster compression
* at the expense of memory usage. The default value is {@code 8}
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public JZlibEncoder(int compressionLevel, int windowBits, int memLevel, byte[] dictionary) {
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException("compressionLevel: " + compressionLevel + " (expected: 0-9)");
}
if (windowBits < 9 || windowBits > 15) {
throw new IllegalArgumentException(
"windowBits: " + windowBits + " (expected: 9-15)");
}
if (memLevel < 1 || memLevel > 9) {
throw new IllegalArgumentException(
"memLevel: " + memLevel + " (expected: 1-9)");
}
if (dictionary == null) {
throw new NullPointerException("dictionary");
}
int resultCode;
resultCode = z.deflateInit(
compressionLevel, windowBits, memLevel,
JZlib.W_ZLIB); // Default: ZLIB format
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "initialization failure", resultCode);
} else {
resultCode = z.deflateSetDictionary(dictionary, dictionary.length);
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "failed to set the dictionary", resultCode);
}
}
wrapperOverhead = ZlibUtil.wrapperOverhead(ZlibWrapper.ZLIB);
}
@Override
public ChannelFuture close() {
return close(ctx().channel().newPromise());
}
@Override
public ChannelFuture close(final ChannelPromise promise) {
ChannelHandlerContext ctx = ctx();
EventExecutor executor = ctx.executor();
if (executor.inEventLoop()) {
return finishEncode(ctx, promise);
} else {
final ChannelPromise p = ctx.newPromise();
executor.execute(new Runnable() {
@Override
public void run() {
ChannelFuture f = finishEncode(ctx(), p);
f.addListener(new ChannelPromiseNotifier(promise));
}
});
return p;
}
}
private ChannelHandlerContext ctx() {
ChannelHandlerContext ctx = this.ctx;
if (ctx == null) {
throw new IllegalStateException("not added to a pipeline");
}
return ctx;
}
@Override
public boolean isClosed() {
return finished;
}
@Override
protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception {
if (finished) {
out.writeBytes(in);
return;
}
int inputLength = in.readableBytes();
if (inputLength == 0) {
return;
}
try {
// Configure input.
boolean inHasArray = in.hasArray();
z.avail_in = inputLength;
if (inHasArray) {
z.next_in = in.array();
z.next_in_index = in.arrayOffset() + in.readerIndex();
} else {
byte[] array = new byte[inputLength];
in.getBytes(in.readerIndex(), array);
z.next_in = array;
z.next_in_index = 0;
}
int oldNextInIndex = z.next_in_index;
// Configure output.
int maxOutputLength = (int) Math.ceil(inputLength * 1.001) + 12 + wrapperOverhead;
out.ensureWritable(maxOutputLength);
z.avail_out = maxOutputLength;
z.next_out = out.array();
z.next_out_index = out.arrayOffset() + out.writerIndex();
int oldNextOutIndex = z.next_out_index;
// Note that Z_PARTIAL_FLUSH has been deprecated.
int resultCode;
try {
resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
} finally {
in.skipBytes(z.next_in_index - oldNextInIndex);
}
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "compression failure", resultCode);
}
int outputLength = z.next_out_index - oldNextOutIndex;
if (outputLength > 0) {
out.writerIndex(out.writerIndex() + outputLength);
}
} finally {
// Deference the external references explicitly to tell the VM that
// the allocated byte arrays are temporary so that the call stack
// can be utilized.
// I'm not sure if the modern VMs do this optimization though.
z.next_in = null;
z.next_out = null;
}
}
@Override
public void close(
final ChannelHandlerContext ctx,
final ChannelPromise promise) {
ChannelFuture f = finishEncode(ctx, ctx.newPromise());
f.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
ctx.close(promise);
}
});
if (!f.isDone()) {
// Ensure the channel is closed even if the write operation completes in time.
ctx.executor().schedule(new Runnable() {
@Override
public void run() {
ctx.close(promise);
}
}, 10, TimeUnit.SECONDS); // FIXME: Magic number
}
}
private ChannelFuture finishEncode(ChannelHandlerContext ctx, ChannelPromise promise) {
if (finished) {
promise.setSuccess();
return promise;
}
finished = true;
ByteBuf footer;
try {
// Configure input.
z.next_in = EmptyArrays.EMPTY_BYTES;
z.next_in_index = 0;
z.avail_in = 0;
// Configure output.
byte[] out = new byte[32]; // room for ADLER32 + ZLIB / CRC32 + GZIP header
z.next_out = out;
z.next_out_index = 0;
z.avail_out = out.length;
// Write the ADLER32 checksum (stream footer).
int resultCode = z.deflate(JZlib.Z_FINISH);
if (resultCode != JZlib.Z_OK && resultCode != JZlib.Z_STREAM_END) {
promise.setFailure(ZlibUtil.deflaterException(z, "compression failure", resultCode));
return promise;
} else if (z.next_out_index != 0) {
footer = Unpooled.wrappedBuffer(out, 0, z.next_out_index);
} else {
footer = Unpooled.EMPTY_BUFFER;
}
} finally {
z.deflateEnd();
// Deference the external references explicitly to tell the VM that
// the allocated byte arrays are temporary so that the call stack
// can be utilized.
// I'm not sure if the modern VMs do this optimization though.
z.next_in = null;
z.next_out = null;
}
return ctx.writeAndFlush(footer, promise);
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
}
}