001 /**
002 *
003 * Copyright 2004 Protique Ltd
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 **/
018
019 package org.activemq.io.util;
020 import java.io.IOException;
021 import java.util.zip.Deflater;
022 import java.util.zip.GZIPInputStream;
023
024 /**
025 * Compression stream
026 *
027 * @version $Revision: 1.1.1.1 $
028 */
029 public class ByteArrayCompression{
030
031 /**
032 * Data size above which compression will be used
033 */
034 public static final int DEFAULT_COMPRESSION_LIMIT = 32 * 1024;
035
036 /**
037 * Default compression level - 0 being none, 9 being best
038 */
039 public static final int DEFAULT_COMPRESSION_LEVEL = Deflater.BEST_SPEED;
040
041 /**
042 * Default Compression Strategy
043 */
044 public static final int DEFAULT_COMPRESSION_STRATEGY = Deflater.DEFAULT_STRATEGY;
045
046 private int compressionLimit = DEFAULT_COMPRESSION_LIMIT;
047 private int compressionLevel = DEFAULT_COMPRESSION_LEVEL;
048 private int compressionStrategy = DEFAULT_COMPRESSION_STRATEGY;//default compression strategy
049
050 /**
051 * @return Returns the compressionLevel.
052 */
053 public int getCompressionLevel() {
054 return compressionLevel;
055 }
056 /**
057 * @param compressionLevel The compressionLevel to set.
058 */
059 public void setCompressionLevel(int compressionLevel) {
060 this.compressionLevel = compressionLevel;
061 }
062 /**
063 * @return Returns the compressionLimit.
064 */
065 public int getCompressionLimit() {
066 return compressionLimit;
067 }
068 /**
069 * @param compressionLimit The compressionLimit to set.
070 */
071 public void setCompressionLimit(int compressionLimit) {
072 this.compressionLimit = compressionLimit;
073 }
074 /**
075 * @return Returns the compressionStrategy.
076 */
077 public int getCompressionStrategy() {
078 return compressionStrategy;
079 }
080 /**
081 * @param compressionStrategy The compressionStrategy to set.
082 */
083 public void setCompressionStrategy(int compressionStrategy) {
084 this.compressionStrategy = compressionStrategy;
085 }
086 /**
087 * test for compressed data
088 * @param ba
089 * @return true if the data in the ByteArray is compressed
090 */
091 public static boolean isCompressed(ByteArray ba){
092 boolean answer = false;
093 if (ba != null && ba.getLength() > 2){
094 answer = ((int)(ba.get(0) & 0xff) | (int)((ba.get(1) & 0xff)<< 8)) == GZIPInputStream.GZIP_MAGIC;
095 }
096 return answer;
097 }
098
099 /**
100 * Deflate the data in the ByteArray
101 * @param ba
102 * @return the passed in ba if data is not compressed else a new ByteArray
103 * @throws IOException
104 */
105 public ByteArray deflate(ByteArray ba) throws IOException{
106 ByteArray answer = ba;
107 if (ba != null && ba.getLength() > compressionLimit && !ByteArrayCompression.isCompressed(ba)){
108 WireByteArrayOutputStream bytesOut = new WireByteArrayOutputStream();
109 WireGZIPOutputStream gzipOut = new WireGZIPOutputStream(bytesOut);
110 gzipOut.getDeflater().setStrategy(compressionStrategy);
111 gzipOut.getDeflater().setLevel(compressionLevel);
112 gzipOut.write(ba.getBuf(),ba.getOffset(),ba.getLength());
113 gzipOut.close();
114 bytesOut.close();
115 answer = new ByteArray(bytesOut.getData(),0,bytesOut.size());
116 }
117 return answer;
118 }
119
120 /**
121 * Inflate a ByteArray (if it contains compressed data)
122 * @param ba
123 * @return the inflated ByteArray
124 * @throws IOException
125 */
126 public ByteArray inflate(ByteArray ba) throws IOException {
127 ByteArray answer = ba;
128 if (ba != null && ByteArrayCompression.isCompressed(ba)){
129 WireByteArrayInputStream bytesIn = new WireByteArrayInputStream(ba);
130 GZIPInputStream gzipIn = new GZIPInputStream(bytesIn);
131 WireByteArrayOutputStream bytesOut = new WireByteArrayOutputStream();
132 byte[] buffer = new byte[1024];
133 int count = 0;
134 while ((count = gzipIn.read(buffer)) > 0 ){
135 bytesOut.write(buffer,0,count);
136 }
137 bytesOut.close();
138 answer = new ByteArray(bytesOut.getData(),0,bytesOut.size());
139 }
140 return answer;
141 }
142
143 }