/*
* Copyright 2013 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.spdy;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.Unpooled;
import java.util.zip.Deflater;
import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
class SpdyHeaderBlockZlibEncoder extends SpdyHeaderBlockRawEncoder {
private final Deflater compressor;
private boolean finished;
SpdyHeaderBlockZlibEncoder(SpdyVersion spdyVersion, int compressionLevel) {
super(spdyVersion);
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException(
"compressionLevel: " + compressionLevel + " (expected: 0-9)");
}
compressor = new Deflater(compressionLevel);
compressor.setDictionary(SPDY_DICT);
}
private int setInput(ByteBuf decompressed) {
int len = decompressed.readableBytes();
if (decompressed.hasArray()) {
compressor.setInput(decompressed.array(), decompressed.arrayOffset() + decompressed.readerIndex(), len);
} else {
byte[] in = new byte[len];
decompressed.getBytes(decompressed.readerIndex(), in);
compressor.setInput(in, 0, in.length);
}
return len;
}
private ByteBuf encode(ByteBufAllocator alloc, int len) {
ByteBuf compressed = alloc.heapBuffer(len);
boolean release = true;
try {
while (compressInto(compressed)) {
// Although unlikely, it's possible that the compressed size is larger than the decompressed size
compressed.ensureWritable(compressed.capacity() << 1);
}
release = false;
return compressed;
} finally {
if (release) {
compressed.release();
}
}
}
private boolean compressInto(ByteBuf compressed) {
byte[] out = compressed.array();
int off = compressed.arrayOffset() + compressed.writerIndex();
int toWrite = compressed.writableBytes();
int numBytes = compressor.deflate(out, off, toWrite, Deflater.SYNC_FLUSH);
compressed.writerIndex(compressed.writerIndex() + numBytes);
return numBytes == toWrite;
}
@Override
public ByteBuf encode(ByteBufAllocator alloc, SpdyHeadersFrame frame) throws Exception {
if (frame == null) {
throw new IllegalArgumentException("frame");
}
if (finished) {
return Unpooled.EMPTY_BUFFER;
}
ByteBuf decompressed = super.encode(alloc, frame);
try {
if (!decompressed.isReadable()) {
return Unpooled.EMPTY_BUFFER;
}
int len = setInput(decompressed);
return encode(alloc, len);
} finally {
decompressed.release();
}
}
@Override
public void end() {
if (finished) {
return;
}
finished = true;
compressor.end();
super.end();
}
}