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 DeflaterOutputStream def = new DeflaterOutputStream(out, new Deflater(Deflater.DEFLATED, NOWRAP)); 063 def.write(bytes); 064 def.close(); 065 066 return out.toByteArray(); 067 } 068 069 070 /** 071 * Decompresses the specified byte array according to the DEFLATE 072 * specification (RFC 1951). 073 * 074 * @param bytes The byte array to decompress. Must not be {@code null}. 075 * 076 * @return The decompressed bytes. 077 * 078 * @throws IOException If decompression failed. 079 */ 080 public static byte[] decompress(final byte[] bytes) 081 throws IOException { 082 083 InflaterInputStream inf = new InflaterInputStream(new ByteArrayInputStream(bytes), new Inflater(NOWRAP)); 084 ByteArrayOutputStream out = new ByteArrayOutputStream(); 085 086 // Transfer bytes from the compressed array to the output 087 byte[] buf = new byte[1024]; 088 089 int len; 090 091 while ((len = inf.read(buf)) > 0) { 092 093 out.write(buf, 0, len); 094 } 095 096 inf.close(); 097 out.close(); 098 099 return out.toByteArray(); 100 } 101 102 103 /** 104 * Prevents public instantiation. 105 */ 106 private DeflateUtils() { 107 108 } 109}