/*

 * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.

 * 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   1.0

 */

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 {@code 0} through {@code buf.length}; elements

     * {@code buf[0]} through {@code buf[count-1]} 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.

     * @throws  IllegalArgumentException if size <= 0.

     */

    public BufferedOutputStream(OutputStream out, int size) {

        super(out);

        if (size <= 0) {

            throw new IllegalArgumentException("Buffer size <= 0");

        }

        buf = new byte[size];

    }

    /** Flush the internal buffer */

    private void flushBuffer() throws IOException {

        if (count > 0) {

            out.write(buf, 0, count);

            count = 0;

        }

    }

    /**

     * Writes the specified byte to this buffered output stream.

     *

     * @param      b   the byte to be written.

     * @throws     IOException  if an I/O error occurs.

     */

    @Override

    public synchronized void write(int b) throws IOException {

        if (count >= buf.length) {

            flushBuffer();

        }

        buf[count++] = (byte)b;

    }

    /**

     *

     * <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

     *

     * @param      b     the data.

     * @param      off   the start offset in the data.

     * @param      len   the number of bytes to write.

     * @throws     IOException  if an I/O error occurs.

     */

    @Override

    public synchronized void write(byte b[], int off, int len) throws IOException {

        if (len >= 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();

            out.write(b, off, len);

            return;

        }

        if (len > buf.length - count) {

            flushBuffer();

        }

        System.arraycopy(b, off, buf, count, len);

        count += len;

    }

    /**

     * Flushes this buffered output stream. This forces any buffered

     * output bytes to be written out to the underlying output stream.

     *

     * @throws     IOException  if an I/O error occurs.

     * @see        java.io.FilterOutputStream#out

     */

    @Override

    public synchronized void flush() throws IOException {

        flushBuffer();

        out.flush();

    }

}