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.formats.webp.chunks; 018 019import java.io.IOException; 020import java.io.PrintWriter; 021import java.nio.ByteOrder; 022import java.nio.charset.StandardCharsets; 023 024import org.apache.commons.imaging.ImagingException; 025import org.apache.commons.imaging.common.BinaryFileParser; 026import org.apache.commons.imaging.internal.SafeOperations; 027 028/** 029 * A WebP image is composed of several chunks. This is the base class for the chunks, used by the parser. 030 * 031 * @see <a href="https://developers.google.com/speed/webp/docs/riff_container">WebP Container Specification</a> 032 * @since 1.0.0-alpha4 033 */ 034public abstract class AbstractWebPChunk extends BinaryFileParser { 035 036 private static boolean checkArgs(final int size, final byte[] bytes) throws ImagingException { 037 if (size != bytes.length) { 038 throw new ImagingException("Chunk size must match bytes length"); 039 } 040 return true; 041 } 042 043 private final int type; 044 private final int size; 045 protected final byte[] bytes; 046 private final int chunkSize; 047 048 /** 049 * Create a new WebP chunk. 050 * 051 * @param type chunk type. 052 * @param size chunk size. 053 * @param bytes chunk data. 054 * @throws ImagingException if the chunk data and the size provided do not match. 055 */ 056 public AbstractWebPChunk(final int type, final int size, final byte[] bytes) throws ImagingException { 057 this(type, size, bytes, checkArgs(size, bytes)); 058 } 059 060 private AbstractWebPChunk(final int type, final int size, final byte[] bytes, final boolean ignored) { 061 super(ByteOrder.LITTLE_ENDIAN); 062 this.type = type; 063 this.size = bytes.length; 064 this.bytes = bytes; 065 // if chunk size is odd, a single padding byte is added 066 final int padding = size % 2 != 0 ? 1 : 0; 067 // Chunk FourCC (4 bytes) + Chunk Size (4 bytes) + Chunk Payload (n bytes) + Padding 068 this.chunkSize = SafeOperations.add(4, 4, size, padding); 069 } 070 071 /** 072 * Print the chunk to the given stream. 073 * 074 * @param pw a stream to write to. 075 * @param offset chunk offset. 076 * @throws ImagingException if the image is invalid. 077 * @throws IOException if it fails to write to the given stream. 078 */ 079 public void dump(final PrintWriter pw, final int offset) throws ImagingException, IOException { 080 pw.printf("Chunk %s at offset %s, length %d%n, payload size %d%n", getTypeDescription(), offset >= 0 ? String.valueOf(offset) : "unknown", 081 getChunkSize(), getPayloadSize()); 082 } 083 084 /** 085 * @return a copy of the chunk data as bytes. 086 */ 087 public byte[] getBytes() { 088 return bytes.clone(); 089 } 090 091 /** 092 * @return the chunk size. 093 */ 094 public int getChunkSize() { 095 return chunkSize; 096 } 097 098 /** 099 * @return the payload size. 100 */ 101 public int getPayloadSize() { 102 return size; 103 } 104 105 /** 106 * @return the chunk type. 107 */ 108 public int getType() { 109 return type; 110 } 111 112 /** 113 * @return the description of the chunk type. 114 */ 115 public String getTypeDescription() { 116 return new String(new byte[] { (byte) (type & 0xff), (byte) (type >> 8 & 0xff), (byte) (type >> 16 & 0xff), (byte) (type >> 24 & 0xff) }, 117 StandardCharsets.UTF_8); 118 } 119}