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/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed 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 com.google.common.io;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Preconditions;
import com.google.common.primitives.Longs;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* An implementation of {@link DataOutput} that uses little-endian byte ordering for writing {@code
* char}, {@code short}, {@code int}, {@code float}, {@code double}, and {@code long} values.
*
* <p><b>Note:</b> This class intentionally violates the specification of its supertype {@code
* DataOutput}, which explicitly requires big-endian byte order.
*
* @author Chris Nokleberg
* @author Keith Bottner
* @since 8.0
*/
@Beta
@GwtIncompatible
public final class LittleEndianDataOutputStream extends FilterOutputStream implements DataOutput {
/**
* Creates a {@code LittleEndianDataOutputStream} that wraps the given stream.
*
* @param out the stream to delegate to
*/
public LittleEndianDataOutputStream(OutputStream out) {
super(new DataOutputStream(Preconditions.checkNotNull(out)));
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
// Override slow FilterOutputStream impl
out.write(b, off, len);
}
@Override
public void writeBoolean(boolean v) throws IOException {
((DataOutputStream) out).writeBoolean(v);
}
@Override
public void writeByte(int v) throws IOException {
((DataOutputStream) out).writeByte(v);
}
/**
* @deprecated The semantics of {@code writeBytes(String s)} are considered dangerous. Please use
* {@link #writeUTF(String s)}, {@link #writeChars(String s)} or another write method instead.
*/
@Deprecated
@Override
public void writeBytes(String s) throws IOException {
((DataOutputStream) out).writeBytes(s);
}
/**
* Writes a char as specified by {@link DataOutputStream#writeChar(int)}, except using
* little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeChar(int v) throws IOException {
writeShort(v);
}
/**
* Writes a {@code String} as specified by {@link DataOutputStream#writeChars(String)}, except
* each character is written using little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeChars(String s) throws IOException {
for (int i = 0; i < s.length(); i++) {
writeChar(s.charAt(i));
}
}
/**
* Writes a {@code double} as specified by {@link DataOutputStream#writeDouble(double)}, except
* using little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeDouble(double v) throws IOException {
writeLong(Double.doubleToLongBits(v));
}
/**
* Writes a {@code float} as specified by {@link DataOutputStream#writeFloat(float)}, except using
* little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeFloat(float v) throws IOException {
writeInt(Float.floatToIntBits(v));
}
/**
* Writes an {@code int} as specified by {@link DataOutputStream#writeInt(int)}, except using
* little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeInt(int v) throws IOException {
out.write(0xFF & v);
out.write(0xFF & (v >> 8));
out.write(0xFF & (v >> 16));
out.write(0xFF & (v >> 24));
}
/**
* Writes a {@code long} as specified by {@link DataOutputStream#writeLong(long)}, except using
* little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeLong(long v) throws IOException {
byte[] bytes = Longs.toByteArray(Long.reverseBytes(v));
write(bytes, 0, bytes.length);
}
/**
* Writes a {@code short} as specified by {@link DataOutputStream#writeShort(int)}, except using
* little-endian byte order.
*
* @throws IOException if an I/O error occurs
*/
@Override
public void writeShort(int v) throws IOException {
out.write(0xFF & v);
out.write(0xFF & (v >> 8));
}
@Override
public void writeUTF(String str) throws IOException {
((DataOutputStream) out).writeUTF(str);
}
// Overriding close() because FilterOutputStream's close() method pre-JDK8 has bad behavior:
// it silently ignores any exception thrown by flush(). Instead, just close the delegate stream.
// It should flush itself if necessary.
@Override
public void close() throws IOException {
out.close();
}
}
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