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The Apache Commons IO library contains utility classes, stream implementations, file filters,
file comparators, endian transformation classes, and much more.
/*
* 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 static org.apache.commons.io.IOUtils.EOF;
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.
*
* Origin of code: Avalon Excalibur (IO)
*
*
*/
public class SwappedDataInputStream extends ProxyInputStream implements DataInput {
/**
* Constructs a SwappedDataInputStream.
*
* @param input InputStream to read from
*/
public SwappedDataInputStream(final InputStream input) {
super(input);
}
/**
* Return {@link #readByte()} != 0
*
* @return false if the byte read is zero, otherwise true
* @throws IOException if an I/O error occurs.
* @throws EOFException if an end of file is reached unexpectedly
*/
@Override
public boolean readBoolean() throws IOException, EOFException {
return 0 != readByte();
}
/**
* Invokes the delegate's {@code read()} 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
*/
@Override
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
*/
@Override
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
*/
@Override
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
*/
@Override
public float readFloat() throws IOException, EOFException {
return EndianUtils.readSwappedFloat(in);
}
/**
* Invokes the delegate's {@code read(byte[] data, int, int)} 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.
*/
@Override
public void readFully(final byte[] data) throws IOException, EOFException {
readFully(data, 0, data.length);
}
/**
* Invokes the delegate's {@code read(byte[] data, int, int)} 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.
*/
@Override
public void readFully(final byte[] data, final int offset, final int length) throws IOException, EOFException {
int remaining = length;
while (remaining > 0) {
final int location = offset + length - remaining;
final int count = read(data, location, remaining);
if (EOF == 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.
*/
@Override
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.
*/
@Override
public String readLine() throws IOException, EOFException {
throw UnsupportedOperationExceptions.method("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.
*/
@Override
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.
*/
@Override
public short readShort() throws IOException, EOFException {
return EndianUtils.readSwappedShort(in);
}
/**
* Invokes the delegate's {@code read()} 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.
*/
@Override
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.
*/
@Override
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.
*/
@Override
public String readUTF() throws IOException, EOFException {
throw UnsupportedOperationExceptions.method("readUTF");
}
/**
* Invokes the delegate's {@code skip(int)} 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.
*/
@Override
public int skipBytes(final int count) throws IOException, EOFException {
return (int) in.skip(count);
}
}