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.bytesource; 018 019import java.io.IOException; 020import java.io.InputStream; 021 022import org.apache.commons.imaging.common.BinaryFunctions; 023 024public abstract class ByteSource { 025 private final String fileName; 026 027 public ByteSource(final String fileName) { 028 this.fileName = fileName; 029 } 030 031 public final InputStream getInputStream(final long start) throws IOException { 032 InputStream is = null; 033 boolean succeeded = false; 034 try { 035 is = getInputStream(); 036 BinaryFunctions.skipBytes(is, start); 037 succeeded = true; 038 } finally { 039 if (!succeeded && is != null) { 040 is.close(); 041 } 042 } 043 return is; 044 } 045 046 public abstract InputStream getInputStream() throws IOException; 047 048 public byte[] getBlock(final int start, final int length) throws IOException { 049 return getBlock(0xFFFFffffL & start, length); 050 } 051 052 public abstract byte[] getBlock(long start, int length) throws IOException; 053 054 public abstract byte[] getAll() throws IOException; 055 056 /** 057 * This operation can be VERY expensive; for inputstream byte sources, the 058 * entire stream must be drained to determine its length. 059 * 060 * @return the byte source length 061 * @throws IOException if it fails to read the byte source data 062 */ 063 public abstract long getLength() throws IOException; 064 065 public abstract String getDescription(); 066 067 public final String getFileName() { 068 return fileName; 069 } 070 071}