Source code: org/activemq/io/util/ByteArrayCompression.java
1 /**
2 *
3 * Copyright 2004 Protique Ltd
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 **/
18
19 package org.activemq.io.util;
20 import java.io.IOException;
21 import java.util.zip.Deflater;
22 import java.util.zip.GZIPInputStream;
23
24 /**
25 * Compression stream
26 *
27 * @version $Revision: 1.1.1.1 $
28 */
29 public class ByteArrayCompression{
30
31 /**
32 * Data size above which compression will be used
33 */
34 public static final int DEFAULT_COMPRESSION_LIMIT = 32 * 1024;
35
36 /**
37 * Default compression level - 0 being none, 9 being best
38 */
39 public static final int DEFAULT_COMPRESSION_LEVEL = Deflater.BEST_SPEED;
40
41 /**
42 * Default Compression Strategy
43 */
44 public static final int DEFAULT_COMPRESSION_STRATEGY = Deflater.DEFAULT_STRATEGY;
45
46 private int compressionLimit = DEFAULT_COMPRESSION_LIMIT;
47 private int compressionLevel = DEFAULT_COMPRESSION_LEVEL;
48 private int compressionStrategy = DEFAULT_COMPRESSION_STRATEGY;//default compression strategy
49
50 /**
51 * @return Returns the compressionLevel.
52 */
53 public int getCompressionLevel() {
54 return compressionLevel;
55 }
56 /**
57 * @param compressionLevel The compressionLevel to set.
58 */
59 public void setCompressionLevel(int compressionLevel) {
60 this.compressionLevel = compressionLevel;
61 }
62 /**
63 * @return Returns the compressionLimit.
64 */
65 public int getCompressionLimit() {
66 return compressionLimit;
67 }
68 /**
69 * @param compressionLimit The compressionLimit to set.
70 */
71 public void setCompressionLimit(int compressionLimit) {
72 this.compressionLimit = compressionLimit;
73 }
74 /**
75 * @return Returns the compressionStrategy.
76 */
77 public int getCompressionStrategy() {
78 return compressionStrategy;
79 }
80 /**
81 * @param compressionStrategy The compressionStrategy to set.
82 */
83 public void setCompressionStrategy(int compressionStrategy) {
84 this.compressionStrategy = compressionStrategy;
85 }
86 /**
87 * test for compressed data
88 * @param ba
89 * @return true if the data in the ByteArray is compressed
90 */
91 public static boolean isCompressed(ByteArray ba){
92 boolean answer = false;
93 if (ba != null && ba.getLength() > 2){
94 answer = ((int)(ba.get(0) & 0xff) | (int)((ba.get(1) & 0xff)<< 8)) == GZIPInputStream.GZIP_MAGIC;
95 }
96 return answer;
97 }
98
99 /**
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 }