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/*
 *  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 java.io;

import com.jtransc.JTranscBits;

import java.nio.charset.StandardCharsets;
import java.nio.internal.SizeOf;

/**
 * Wraps an existing {@link OutputStream} and writes big-endian typed data to it.
 * Typically, this stream can be read in by DataInputStream. Types that can be
 * written include byte, 16-bit short, 32-bit int, 32-bit float, 64-bit long,
 * 64-bit double, byte strings, and {@link DataInput MUTF-8} encoded strings.
 *
 * @see DataInputStream
 */
public class DataOutputStream extends FilterOutputStream implements DataOutput {
	private final byte[] scratch = new byte[8];

	/**
	 * The number of bytes written out so far.
	 */
	protected int written;

	/**
	 * Constructs a new {@code DataOutputStream} on the {@code OutputStream}
	 * {@code out}. Note that data written by this stream is not in a human
	 * readable form but can be reconstructed by using a {@link DataInputStream}
	 * on the resulting output.
	 *
	 * @param out the target stream for writing.
	 */
	public DataOutputStream(OutputStream out) {
		super(out);
	}

	/**
	 * Flushes this stream to ensure all pending data is sent out to the target
	 * stream. This implementation then also flushes the target stream.
	 *
	 * @throws IOException if an error occurs attempting to flush this stream.
	 */
	@Override
	public void flush() throws IOException {
		super.flush();
	}

	/**
	 * Returns the total number of bytes written to the target stream so far.
	 *
	 * @return the number of bytes written to the target stream.
	 */
	public final int size() {
		if (written < 0) {
			written = Integer.MAX_VALUE;
		}
		return written;
	}

	/**
	 * Writes {@code count} bytes from the byte array {@code buffer} starting at
	 * {@code offset} to the target stream.
	 *
	 * @param buffer the buffer to write to the target stream.
	 * @param offset the index of the first byte in {@code buffer} to write.
	 * @param count  the number of bytes from the {@code buffer} to write.
	 * @throws IOException          if an error occurs while writing to the target stream.
	 * @throws NullPointerException if {@code buffer} is {@code null}.
	 */
	@Override
	public void write(byte[] buffer, int offset, int count) throws IOException {
		if (buffer == null) {
			throw new NullPointerException("buffer == null");
		}
		out.write(buffer, offset, count);
		written += count;
	}

	/**
	 * Writes a byte to the target stream. Only the least significant byte of
	 * the integer {@code oneByte} is written.
	 *
	 * @param oneByte the byte to write to the target stream.
	 * @throws IOException if an error occurs while writing to the target stream.
	 * @see DataInputStream#readByte()
	 */
	@Override
	public void write(int oneByte) throws IOException {
		out.write(oneByte);
		written++;
	}

	/**
	 * Writes a boolean to the target stream.
	 *
	 * @param val the boolean value to write to the target stream.
	 * @throws IOException if an error occurs while writing to the target stream.
	 * @see DataInputStream#readBoolean()
	 */
	public final void writeBoolean(boolean val) throws IOException {
		out.write(val ? 1 : 0);
		written++;
	}

	/**
	 * Writes an 8-bit byte to the target stream. Only the least significant
	 * byte of the integer {@code val} is written.
	 *
	 * @param val the byte value to write to the target stream.
	 * @throws IOException if an error occurs while writing to the target stream.
	 * @see DataInputStream#readByte()
	 * @see DataInputStream#readUnsignedByte()
	 */
	public final void writeByte(int val) throws IOException {
		out.write(val);
		written++;
	}

	public final void writeBytes(String str) throws IOException {
		if (str.length() == 0) {
			return;
		}
		byte[] bytes = new byte[str.length()];
		for (int index = 0; index < str.length(); index++) {
			bytes[index] = (byte) str.charAt(index);
		}
		out.write(bytes);
		written += bytes.length;
	}

	public final void writeChar(int val) throws IOException {
		writeShort(val);
	}

	public final void writeChars(String str) throws IOException {
		byte[] bytes = str.getBytes("UTF-16BE");
		out.write(bytes);
		written += bytes.length;
	}

	public final void writeDouble(double val) throws IOException {
		writeLong(Double.doubleToLongBits(val));
	}

	public final void writeFloat(float val) throws IOException {
		writeInt(Float.floatToIntBits(val));
	}

	public final void writeInt(int val) throws IOException {
		JTranscBits.writeIntBE(scratch, 0, val);
		out.write(scratch, 0, SizeOf.INT);
		written += SizeOf.INT;
	}

	public final void writeLong(long val) throws IOException {
		JTranscBits.writeLongBE(scratch, 0, val);
		out.write(scratch, 0, SizeOf.LONG);
		written += SizeOf.LONG;
	}

	public final void writeShort(int val) throws IOException {
		JTranscBits.writeShortBE(scratch, 0, (short) val);
		out.write(scratch, 0, SizeOf.SHORT);
		written += SizeOf.SHORT;
	}

	public final void writeUTF(String str) throws IOException {
		write(str.getBytes(StandardCharsets.UTF_8));
	}
}