| /** |
| * 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.avro.file; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.nio.ByteBuffer; |
| import java.util.zip.Deflater; |
| import java.util.zip.DeflaterOutputStream; |
| import java.util.zip.Inflater; |
| import java.util.zip.InflaterOutputStream; |
| |
| /** |
| * Implements DEFLATE (RFC1951) compression and decompression. |
| * |
| * Note that there is a distinction between RFC1951 (deflate) |
| * and RFC1950 (zlib). zlib adds an extra 2-byte header |
| * at the front, and a 4-byte checksum at the end. The |
| * code here, by passing "true" as the "nowrap" option to |
| * {@link Inflater} and {@link Deflater}, is using |
| * RFC1951. |
| */ |
| class DeflateCodec extends Codec { |
| |
| static class Option extends CodecFactory { |
| private int compressionLevel; |
| |
| Option(int compressionLevel) { |
| this.compressionLevel = compressionLevel; |
| } |
| |
| @Override |
| protected Codec createInstance() { |
| return new DeflateCodec(compressionLevel); |
| } |
| } |
| |
| private ByteArrayOutputStream outputBuffer; |
| private Deflater deflater; |
| private Inflater inflater; |
| //currently only do 'nowrap' -- RFC 1951, not zlib |
| private boolean nowrap = true; |
| private int compressionLevel; |
| |
| public DeflateCodec(int compressionLevel) { |
| this.compressionLevel = compressionLevel; |
| } |
| |
| @Override |
| public String getName() { |
| return DataFileConstants.DEFLATE_CODEC; |
| } |
| |
| @Override |
| public ByteBuffer compress(ByteBuffer data) throws IOException { |
| ByteArrayOutputStream baos = getOutputBuffer(data.remaining()); |
| DeflaterOutputStream ios = new DeflaterOutputStream(baos, getDeflater()); |
| writeAndClose(data, ios); |
| ByteBuffer result = ByteBuffer.wrap(baos.toByteArray()); |
| return result; |
| } |
| |
| @Override |
| public ByteBuffer decompress(ByteBuffer data) throws IOException { |
| ByteArrayOutputStream baos = getOutputBuffer(data.remaining()); |
| InflaterOutputStream ios = new InflaterOutputStream(baos, getInflater()); |
| writeAndClose(data, ios); |
| ByteBuffer result = ByteBuffer.wrap(baos.toByteArray()); |
| return result; |
| } |
| |
| private void writeAndClose(ByteBuffer data, OutputStream to) throws IOException { |
| byte[] input = data.array(); |
| int offset = data.arrayOffset() + data.position(); |
| int length = data.remaining(); |
| try { |
| to.write(input, offset, length); |
| } finally { |
| to.close(); |
| } |
| } |
| |
| // get and initialize the inflater for use. |
| private Inflater getInflater() { |
| if (null == inflater) { |
| inflater = new Inflater(nowrap); |
| } |
| inflater.reset(); |
| return inflater; |
| } |
| |
| // get and initialize the deflater for use. |
| private Deflater getDeflater() { |
| if (null == deflater) { |
| deflater = new Deflater(compressionLevel, nowrap); |
| } |
| deflater.reset(); |
| return deflater; |
| } |
| |
| // get and initialize the output buffer for use. |
| private ByteArrayOutputStream getOutputBuffer(int suggestedLength) { |
| if (null == outputBuffer) { |
| outputBuffer = new ByteArrayOutputStream(suggestedLength); |
| } |
| outputBuffer.reset(); |
| return outputBuffer; |
| } |
| |
| @Override |
| public int hashCode() { |
| return nowrap ? 0 : 1; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) |
| return true; |
| if (getClass() != obj.getClass()) |
| return false; |
| DeflateCodec other = (DeflateCodec)obj; |
| return (this.nowrap == other.nowrap); |
| } |
| |
| @Override |
| public String toString() { |
| return getName() + "-" + compressionLevel; |
| } |
| } |