Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2009 Mike Cumings |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.kenai.jbosh; |
| 18 | |
| 19 | import java.io.ByteArrayInputStream; |
| 20 | import java.io.ByteArrayOutputStream; |
| 21 | import java.io.IOException; |
| 22 | import java.util.zip.DeflaterOutputStream; |
| 23 | import java.util.zip.InflaterInputStream; |
| 24 | |
| 25 | /** |
| 26 | * Codec methods for compressing and uncompressing using ZLIB. |
| 27 | */ |
| 28 | final class ZLIBCodec { |
| 29 | |
| 30 | /** |
| 31 | * Size of the internal buffer when decoding. |
| 32 | */ |
| 33 | private static final int BUFFER_SIZE = 512; |
| 34 | |
| 35 | /////////////////////////////////////////////////////////////////////////// |
| 36 | // Constructors: |
| 37 | |
| 38 | /** |
| 39 | * Prevent construction. |
| 40 | */ |
| 41 | private ZLIBCodec() { |
| 42 | // Empty |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * Returns the name of the codec. |
| 47 | * |
| 48 | * @return string name of the codec (i.e., "deflate") |
| 49 | */ |
| 50 | public static String getID() { |
| 51 | return "deflate"; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Compress/encode the data provided using the ZLIB format. |
| 56 | * |
| 57 | * @param data data to compress |
| 58 | * @return compressed data |
| 59 | * @throws IOException on compression failure |
| 60 | */ |
| 61 | public static byte[] encode(final byte[] data) throws IOException { |
| 62 | ByteArrayOutputStream byteOut = new ByteArrayOutputStream(); |
| 63 | DeflaterOutputStream deflateOut = null; |
| 64 | try { |
| 65 | deflateOut = new DeflaterOutputStream(byteOut); |
| 66 | deflateOut.write(data); |
| 67 | deflateOut.close(); |
| 68 | byteOut.close(); |
| 69 | return byteOut.toByteArray(); |
| 70 | } finally { |
| 71 | deflateOut.close(); |
| 72 | byteOut.close(); |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Uncompress/decode the data provided using the ZLIB format. |
| 78 | * |
| 79 | * @param data data to uncompress |
| 80 | * @return uncompressed data |
| 81 | * @throws IOException on decompression failure |
| 82 | */ |
| 83 | public static byte[] decode(final byte[] compressed) throws IOException { |
| 84 | ByteArrayInputStream byteIn = new ByteArrayInputStream(compressed); |
| 85 | ByteArrayOutputStream byteOut = new ByteArrayOutputStream(); |
| 86 | InflaterInputStream inflaterIn = null; |
| 87 | try { |
| 88 | inflaterIn = new InflaterInputStream(byteIn); |
| 89 | int read; |
| 90 | byte[] buffer = new byte[BUFFER_SIZE]; |
| 91 | do { |
| 92 | read = inflaterIn.read(buffer); |
| 93 | if (read > 0) { |
| 94 | byteOut.write(buffer, 0, read); |
| 95 | } |
| 96 | } while (read >= 0); |
| 97 | return byteOut.toByteArray(); |
| 98 | } finally { |
| 99 | inflaterIn.close(); |
| 100 | byteOut.close(); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | } |