/*
 * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved.
 * Copyright (C) 2014-2020 MicroEJ Corp. - EDC compliance and optimizations.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.io;

/**
 * The class implements a buffered output stream. By setting up such an output stream, an application can write bytes to
 * the underlying output stream without necessarily causing a call to the underlying system for each byte written.
 *
 * @author Arthur van Hoff
 * @since JDK1.0
 */
public class BufferedOutputStream extends FilterOutputStream {
	/**
	 * The internal buffer where data is stored.
	 */
	protected byte buf[];

	/**
	 * The number of valid bytes in the buffer. This value is always in the range <tt>0</tt> through
	 * <tt>buf.length</tt>; elements <tt>buf[0]</tt> through <tt>buf[count-1]</tt> contain valid byte data.
	 */
	protected int count;

	/**
	 * Creates a new buffered output stream to write data to the specified underlying output stream.
	 *
	 * @param out
	 *            the underlying output stream.
	 */
	public BufferedOutputStream(OutputStream out) {
		this(out, 8192);
	}

	/**
	 * Creates a new buffered output stream to write data to the specified underlying output stream with the specified
	 * buffer size.
	 *
	 * @param out
	 *            the underlying output stream.
	 * @param size
	 *            the buffer size.
	 * @exception IllegalArgumentException
	 *                if size &lt;= 0.
	 */
	public BufferedOutputStream(OutputStream out, int size) {
		super(out);
		if (size <= 0) {
			throw new IllegalArgumentException("Buffer size <= 0");
		}
		this.buf = new byte[size];
	}

	/** Flush the internal buffer */
	private void flushBuffer() throws IOException {
		if (this.count > 0) {
			this.out.write(this.buf, 0, this.count);
			this.count = 0;
		}
	}

	/**
	 * Writes the specified byte to this buffered output stream.
	 *
	 * @param b
	 *            the byte to be written.
	 * @exception IOException
	 *                if an I/O error occurs.
	 */
	@Override
	public synchronized void write(int b) throws IOException {
		if (this.count >= this.buf.length) {
			flushBuffer();
		}
		this.buf[this.count++] = (byte) b;
	}

	/**
	 * Writes <code>len</code> bytes from the specified byte array starting at offset <code>off</code> to this buffered
	 * output stream.
	 *
	 * <p>
	 * Ordinarily this method stores bytes from the given array into this stream's buffer, flushing the buffer to the
	 * underlying output stream as needed. If the requested length is at least as large as this stream's buffer,
	 * however, then this method will flush the buffer and write the bytes directly to the underlying output stream.
	 * Thus redundant <code>BufferedOutputStream</code>s will not copy data unnecessarily.
	 *
	 * @param b
	 *            the data.
	 * @param off
	 *            the start offset in the data.
	 * @param len
	 *            the number of bytes to write.
	 * @exception IOException
	 *                if an I/O error occurs.
	 */
	@Override
	public synchronized void write(byte b[], int off, int len) throws IOException {
		if (len >= this.buf.length) {
			/*
			 * If the request length exceeds the size of the output buffer, flush the output buffer and then write the
			 * data directly. In this way buffered streams will cascade harmlessly.
			 */
			flushBuffer();
			this.out.write(b, off, len);
			return;
		}
		if (len > this.buf.length - this.count) {
			flushBuffer();
		}
		System.arraycopy(b, off, this.buf, this.count, len);
		this.count += len;
	}

	/**
	 * Flushes this buffered output stream. This forces any buffered output bytes to be written out to the underlying
	 * output stream.
	 *
	 * @exception IOException
	 *                if an I/O error occurs.
	 * @see java.io.FilterOutputStream#out
	 */
	@Override
	public synchronized void flush() throws IOException {
		flushBuffer();
		this.out.flush();
	}
}