001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. 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 */ 017package org.apache.commons.imaging.common; 018 019import java.io.ByteArrayOutputStream; 020import java.io.IOException; 021import java.util.zip.DataFormatException; 022import java.util.zip.DeflaterOutputStream; 023import java.util.zip.Inflater; 024 025import org.apache.commons.imaging.ImagingException; 026 027/** 028 * <p> 029 * Utility class to compress/decompress bytes using the ZLIB deflate/inflate compression. 030 * </p> 031 * 032 * <p> 033 * <a href="https://www.ietf.org/rfc/rfc1951.txt">RFC 1951 - DEFLATE Compressed Data Format Specification version 1.3</a> 034 * </p> 035 */ 036public final class ZlibDeflate { 037 038 /** 039 * Compress the byte[] using ZLIB deflate compression. 040 * 041 * @param bytes The bytes to compress 042 * @return The compressed bytes. 043 * @throws ImagingException if the bytes could not be compressed. 044 * @see DeflaterOutputStream 045 */ 046 public static byte[] compress(final byte[] bytes) throws ImagingException { 047 final ByteArrayOutputStream out = new ByteArrayOutputStream(Allocator.checkByteArray(bytes.length / 2)); 048 try (DeflaterOutputStream compressOut = new DeflaterOutputStream(out)) { 049 compressOut.write(bytes); 050 } catch (final IOException e) { 051 throw new ImagingException("Unable to compress image", e); 052 } 053 return out.toByteArray(); 054 } 055 056 /** 057 * Compress the byte[] using ZLIB deflate decompression. 058 * 059 * @param bytes The bytes to decompress 060 * @param expectedSize The expected size of the decompressed byte[]. 061 * @return The decompressed bytes. 062 * @throws ImagingException if the bytes could not be decompressed. 063 * @see Inflater 064 */ 065 public static byte[] decompress(final byte[] bytes, final int expectedSize) throws ImagingException { 066 try { 067 final Inflater inflater = new Inflater(); 068 inflater.setInput(bytes); 069 final byte[] result = Allocator.byteArray(expectedSize); 070 inflater.inflate(result); 071 return result; 072 } catch (final DataFormatException e) { 073 throw new ImagingException("Unable to decompress image", e); 074 } 075 } 076 077 private ZlibDeflate() { 078 // empty 079 } 080}