/*

 * Copyright (c) 1997, 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.

 *

 * 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.

 */

/**/

import java.io.*;

public class ABCInputStream extends InputStream {

    int len;

    int chunk;

    int count = 0;

    char next = firstChar();

    ABCInputStream(int len) {

        this(len, len);

    }

    ABCInputStream(int len, int chunk) {

        this.len = len;

        this.chunk = chunk;

    }

    static char firstChar() {

        return 'a';

    }

    static char nextChar(char c) {

        if (c == 'z')

            return '0';

        else if (c == '9')

            return 'a';

        else

            return (char)(c + 1);

    }

    public int read() {

        if (count >= len)

            return -1;

        char c = next;

        next = nextChar(c);

        count++;

        return (byte) c;

    }

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

        int n = (len > chunk) ? chunk : len;

        for (int i = off; i < off + n; i++) {

            int c = read();

            if (c == -1) {

                if (i > off)

                    return i - off;

                else

                    return -1;

            }

            buf[i] = (byte) c;

        }

        return n;

    }

    public int available() {

        int remaining = len - count;

        return (remaining > chunk) ? chunk : remaining;

    }

    public void close() throws IOException {

        if (len == 0)

            throw new IOException("Already closed");

        len = 0;

    }

}