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.ImageReadException; 026import org.apache.commons.imaging.ImageWriteException; 027 028/** 029 * <p> 030 * Utility class to compress/decompress bytes using the ZLIB deflate/inflate 031 * compression. 032 * </p> 033 * 034 * <p> 035 * <a href="http://www.ietf.org/rfc/rfc1951.txt">RFC 1951 - DEFLATE Compressed 036 * Data Format Specification version 1.3</a> 037 * </p> 038 */ 039public class ZlibDeflate { 040 041 /** 042 * Compress the byte[] using ZLIB deflate decompression. 043 * 044 * @param bytes The bytes to decompress 045 * @param expectedSize The expected size of the decompressed byte[]. 046 * 047 * @return The decompressed bytes. 048 * @throws ImageReadException if the bytes could not be decompressed. 049 * @see Inflater 050 */ 051 public static byte[] decompress(final byte[] bytes, final int expectedSize) throws ImageReadException { 052 try { 053 final Inflater inflater = new Inflater(); 054 inflater.setInput(bytes); 055 final byte[] result = new byte[expectedSize]; 056 inflater.inflate(result); 057 return result; 058 } catch (final DataFormatException e) { 059 throw new ImageReadException("Unable to decompress image", e); 060 } 061 } 062 063 /** 064 * Compress the byte[] using ZLIB deflate compression. 065 * 066 * @param bytes The bytes to compress 067 * 068 * @return The compressed bytes. 069 * @throws ImageWriteException if the bytes could not be compressed. 070 * @see DeflaterOutputStream 071 */ 072 public static byte[] compress(final byte[] bytes) throws ImageWriteException { 073 final ByteArrayOutputStream out = new ByteArrayOutputStream(bytes.length / 2); 074 try (DeflaterOutputStream compressOut = new DeflaterOutputStream(out)) { 075 compressOut.write(bytes); 076 } catch (final IOException e) { 077 throw new ImageWriteException("Unable to compress image", e); 078 } 079 return out.toByteArray(); 080 } 081 082}