001/* 002 * nimbus-jose-jwt 003 * 004 * Copyright 2012-2016, Connect2id Ltd. 005 * 006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use 007 * this file except in compliance with the License. You may obtain a copy of the 008 * License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software distributed 013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the 015 * specific language governing permissions and limitations under the License. 016 */ 017 018package com.nimbusds.jose.util; 019 020 021import java.io.ByteArrayInputStream; 022import java.io.ByteArrayOutputStream; 023import java.io.IOException; 024import java.util.zip.Deflater; 025import java.util.zip.DeflaterOutputStream; 026import java.util.zip.InflaterInputStream; 027import java.util.zip.Inflater; 028 029 030/** 031 * Deflate (RFC 1951) utilities. 032 * 033 * @author Vladimir Dzhuvinov 034 * @version 2013-04-16 035 */ 036public class DeflateUtils { 037 038 039 /** 040 * Omit headers and CRC fields from output, as specified by RFC 1950. 041 * Note that the Deflater JavaDocs are incorrect, see 042 * http://stackoverflow.com/questions/11076060/decompressing-gzipped-data-with-inflater-in-java 043 */ 044 private static final boolean NOWRAP = true; 045 046 047 /** 048 * Compresses the specified byte array according to the DEFLATE 049 * specification (RFC 1951). 050 * 051 * @param bytes The byte array to compress. Must not be {@code null}. 052 * 053 * @return The compressed bytes. 054 * 055 * @throws IOException If compression failed. 056 */ 057 public static byte[] compress(final byte[] bytes) 058 throws IOException { 059 060 ByteArrayOutputStream out = new ByteArrayOutputStream(); 061 062 063 Deflater deflater = null; 064 DeflaterOutputStream def = null; 065 try { 066 deflater = new Deflater(Deflater.DEFLATED, NOWRAP); 067 def = new DeflaterOutputStream(out, deflater); 068 def.write(bytes); 069 } finally { 070 if(def != null) { 071 def.close(); 072 } 073 if(deflater != null) { 074 deflater.end(); 075 } 076 } 077 078 return out.toByteArray(); 079 } 080 081 082 /** 083 * Decompresses the specified byte array according to the DEFLATE 084 * specification (RFC 1951). 085 * 086 * @param bytes The byte array to decompress. Must not be {@code null}. 087 * 088 * @return The decompressed bytes. 089 * 090 * @throws IOException If decompression failed. 091 */ 092 public static byte[] decompress(final byte[] bytes) 093 throws IOException { 094 095 Inflater inflater = null; 096 InflaterInputStream inf = null; 097 try { 098 inflater = new Inflater(NOWRAP); 099 inf = new InflaterInputStream(new ByteArrayInputStream(bytes), inflater); 100 101 ByteArrayOutputStream out = new ByteArrayOutputStream(); 102 103 // Transfer bytes from the compressed array to the output 104 byte[] buf = new byte[1024]; 105 106 int len; 107 108 while ((len = inf.read(buf)) > 0) { 109 110 out.write(buf, 0, len); 111 } 112 113 return out.toByteArray(); 114 } finally { 115 if(inf != null) { 116 inf.close(); 117 } 118 if(inflater != null) { 119 inflater.end(); 120 } 121 } 122 } 123 124 125 /** 126 * Prevents public instantiation. 127 */ 128 private DeflateUtils() { 129 130 } 131}