Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.io.input; import java.io.DataInput; import java.io.EOFException; import java.io.IOException; import java.io.InputStream; import org.apache.commons.io.EndianUtils; /** * DataInput for systems relying on little endian data formats. * When read, values will be changed from little endian to big * endian formats for internal usage. * <p> * <b>Origin of code: </b>Avalon Excalibur (IO) * * @author <a href="mailto:peter@apache.org">Peter Donald</a> * @version CVS $Revision: 610010 $ $Date: 2008-01-08 14:50:59 +0000 (Tue, 08 Jan 2008) $ */ public class SwappedDataInputStream extends ProxyInputStream implements DataInput { /** * Constructs a SwappedDataInputStream. * * @param input InputStream to read from */ public SwappedDataInputStream(InputStream input) { super(input); } /** * Return <code>{@link #readByte()} == 0</code> * @return the true if the byte read is zero, otherwise false * @throws IOException if an I/O error occurs * @throws EOFException if an end of file is reached unexpectedly */ public boolean readBoolean() throws IOException, EOFException { return (0 == readByte()); } /** * Invokes the delegate's <code>read()</code> method. * @return the byte read or -1 if the end of stream * @throws IOException if an I/O error occurs * @throws EOFException if an end of file is reached unexpectedly */ public byte readByte() throws IOException, EOFException { return (byte) in.read(); } /** * Reads a character delegating to {@link #readShort()}. * @return the byte read or -1 if the end of stream * @throws IOException if an I/O error occurs * @throws EOFException if an end of file is reached unexpectedly */ public char readChar() throws IOException, EOFException { return (char) readShort(); } /** * Delegates to {@link EndianUtils#readSwappedDouble(InputStream)}. * @return the read long * @throws IOException if an I/O error occurs * @throws EOFException if an end of file is reached unexpectedly */ public double readDouble() throws IOException, EOFException { return EndianUtils.readSwappedDouble(in); } /** * Delegates to {@link EndianUtils#readSwappedFloat(InputStream)}. * @return the read long * @throws IOException if an I/O error occurs * @throws EOFException if an end of file is reached unexpectedly */ public float readFloat() throws IOException, EOFException { return EndianUtils.readSwappedFloat(in); } /** * Invokes the delegate's <code>read(byte[] data, int, int)</code> method. * * @param data the buffer to read the bytes into * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public void readFully(byte[] data) throws IOException, EOFException { readFully(data, 0, data.length); } /** * Invokes the delegate's <code>read(byte[] data, int, int)</code> method. * * @param data the buffer to read the bytes into * @param offset The start offset * @param length The number of bytes to read * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public void readFully(byte[] data, int offset, int length) throws IOException, EOFException { int remaining = length; while (remaining > 0) { int location = offset + (length - remaining); int count = read(data, location, remaining); if (-1 == count) { throw new EOFException(); } remaining -= count; } } /** * Delegates to {@link EndianUtils#readSwappedInteger(InputStream)}. * @return the read long * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public int readInt() throws IOException, EOFException { return EndianUtils.readSwappedInteger(in); } /** * Not currently supported - throws {@link UnsupportedOperationException}. * @return the line read * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public String readLine() throws IOException, EOFException { throw new UnsupportedOperationException("Operation not supported: readLine()"); } /** * Delegates to {@link EndianUtils#readSwappedLong(InputStream)}. * @return the read long * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public long readLong() throws IOException, EOFException { return EndianUtils.readSwappedLong(in); } /** * Delegates to {@link EndianUtils#readSwappedShort(InputStream)}. * @return the read long * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public short readShort() throws IOException, EOFException { return EndianUtils.readSwappedShort(in); } /** * Invokes the delegate's <code>read()</code> method. * @return the byte read or -1 if the end of stream * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public int readUnsignedByte() throws IOException, EOFException { return in.read(); } /** * Delegates to {@link EndianUtils#readSwappedUnsignedShort(InputStream)}. * @return the read long * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public int readUnsignedShort() throws IOException, EOFException { return EndianUtils.readSwappedUnsignedShort(in); } /** * Not currently supported - throws {@link UnsupportedOperationException}. * @return UTF String read * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public String readUTF() throws IOException, EOFException { throw new UnsupportedOperationException("Operation not supported: readUTF()"); } /** * Invokes the delegate's <code>skip(int)</code> method. * @param count the number of bytes to skip * @return the number of bytes to skipped or -1 if the end of stream * @throws EOFException if an end of file is reached unexpectedly * @throws IOException if an I/O error occurs */ public int skipBytes(int count) throws IOException, EOFException { return (int) in.skip(count); } }