/*
 * Copyright (c) 1994, 2015, 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.
 * @exception 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.
 * @exception 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;
 }

 /**
 * 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 >= 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.
 *
 * @exception IOException if an I/O error occurs.
 * @see java.io.FilterOutputStream#out
 */
 @Override
 public synchronized void flush() throws IOException {
 flushBuffer();
 out.flush();
 }
}