/*

 * Copyright (c) 1995, 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;

/**

 * This class allows an application to create an input stream in

 * which the bytes read are supplied by the contents of a string.

 * Applications can also read bytes from a byte array by using a

 * {@code ByteArrayInputStream}.

 * <p>

 * Only the low eight bits of each character in the string are used by

 * this class.

 *

 * @author     Arthur van Hoff

 * @see        java.io.ByteArrayInputStream

 * @see        java.io.StringReader

 * @since      1.0

 * @deprecated This class does not properly convert characters into bytes.  As

 *             of JDK 1.1, the preferred way to create a stream from a

 *             string is via the {@code StringReader} class.

 */

@Deprecated

public

class StringBufferInputStream extends InputStream {

    /**

     * The string from which bytes are read.

     */

    protected String buffer;

    /**

     * The index of the next character to read from the input stream buffer.

     *

     * @see        java.io.StringBufferInputStream#buffer

     */

    protected int pos;

    /**

     * The number of valid characters in the input stream buffer.

     *

     * @see        java.io.StringBufferInputStream#buffer

     */

    protected int count;

    /**

     * Creates a string input stream to read data from the specified string.

     *

     * @param      s   the underlying input buffer.

     */

    public StringBufferInputStream(String s) {

        this.buffer = s;

        count = s.length();

    }

    /**

     * Reads the next byte of data from this input stream. The value

     * byte is returned as an {@code int} in the range

     * {@code 0} to {@code 255}. If no byte is available

     * because the end of the stream has been reached, the value

     * {@code -1} is returned.

     * <p>

     * The {@code read} method of

     * {@code StringBufferInputStream} cannot block. It returns the

     * low eight bits of the next character in this input stream's buffer.

     *

     * @return     the next byte of data, or {@code -1} if the end of the

     *             stream is reached.

     */

    public synchronized int read() {

        return (pos < count) ? (buffer.charAt(pos++) & 0xFF) : -1;

    }

    /**

     * Reads up to {@code len} bytes of data from this input stream

     * into an array of bytes.

     * <p>

     * The {@code read} method of

     * {@code StringBufferInputStream} cannot block. It copies the

     * low eight bits from the characters in this input stream's buffer into

     * the byte array argument.

     *

     * @param      b     the buffer into which the data is read.

     * @param      off   the start offset of the data.

     * @param      len   the maximum number of bytes read.

     * @return     the total number of bytes read into the buffer, or

     *             {@code -1} if there is no more data because the end of

     *             the stream has been reached.

     */

    @SuppressWarnings("deprecation")

    public synchronized int read(byte b[], int off, int len) {

        if (b == null) {

            throw new NullPointerException();

        } else if ((off < 0) || (off > b.length) || (len < 0) ||

                   ((off + len) > b.length) || ((off + len) < 0)) {

            throw new IndexOutOfBoundsException();

        }

        if (pos >= count) {

            return -1;

        }

        int avail = count - pos;

        if (len > avail) {

            len = avail;

        }

        if (len <= 0) {

            return 0;

        }

        buffer.getBytes(pos, pos + len, b, off);

        pos += len;

        return len;

    }

    /**

     * Skips {@code n} bytes of input from this input stream. Fewer

     * bytes might be skipped if the end of the input stream is reached.

     *

     * @param      n   the number of bytes to be skipped.

     * @return     the actual number of bytes skipped.

     */

    public synchronized long skip(long n) {

        if (n < 0) {

            return 0;

        }

        if (n > count - pos) {

            n = count - pos;

        }

        pos += n;

        return n;

    }

    /**

     * Returns the number of bytes that can be read from the input

     * stream without blocking.

     *

     * @return     the value of <code>count&nbsp;-&nbsp;pos</code>, which is the

     *             number of bytes remaining to be read from the input buffer.

     */

    public synchronized int available() {

        return count - pos;

    }

    /**

     * Resets the input stream to begin reading from the first character

     * of this input stream's underlying buffer.

     */

    public synchronized void reset() {

        pos = 0;

    }

}