/*

 * Copyright 2003-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.util;

import java.io.*;

import java.nio.*;

import java.nio.charset.*;

import java.util.Arrays;

/**

 * A utility class for reading passwords

 *

 */

public class Password {

    /** Reads user password from given input stream. */

    public static char[] readPassword(InputStream in) throws IOException {

        char[] consoleEntered = null;

        byte[] consoleBytes = null;

        try {

            // Use the new java.io.Console class

            Console con = null;

            if (in == System.in && ((con = System.console()) != null)) {

                consoleEntered = con.readPassword();

                // readPassword returns "" if you just print ENTER,

                // to be compatible with old Password class, change to null

                if (consoleEntered != null && consoleEntered.length == 0) {

                    return null;

                }

                consoleBytes = convertToBytes(consoleEntered);

                in = new ByteArrayInputStream(consoleBytes);

            }

            // Rest of the lines still necessary for KeyStoreLoginModule

            // and when there is no console.

            char[] lineBuffer;

            char[] buf;

            int i;

            buf = lineBuffer = new char[128];

            int room = buf.length;

            int offset = 0;

            int c;

            boolean done = false;

            while (!done) {

                switch (c = in.read()) {

                  case -1:

                  case '\n':

                      done = true;

                      break;

                  case '\r':

                    int c2 = in.read();

                    if ((c2 != '\n') && (c2 != -1)) {

                        if (!(in instanceof PushbackInputStream)) {

                            in = new PushbackInputStream(in);

                        }

                        ((PushbackInputStream)in).unread(c2);

                    } else {

                        done = true;

                        break;

                    }

                  default:

                    if (--room < 0) {

                        buf = new char[offset + 128];

                        room = buf.length - offset - 1;

                        System.arraycopy(lineBuffer, 0, buf, 0, offset);

                        Arrays.fill(lineBuffer, ' ');

                        lineBuffer = buf;

                    }

                    buf[offset++] = (char) c;

                    break;

                }

            }

            if (offset == 0) {

                return null;

            }

            char[] ret = new char[offset];

            System.arraycopy(buf, 0, ret, 0, offset);

            Arrays.fill(buf, ' ');

            return ret;

        } finally {

            if (consoleEntered != null) {

                Arrays.fill(consoleEntered, ' ');

            }

            if (consoleBytes != null) {

                Arrays.fill(consoleBytes, (byte)0);

            }

        }

    }

    /**

     * Change a password read from Console.readPassword() into

     * its original bytes.

     *

     * @param pass a char[]

     * @return its byte[] format, similar to new String(pass).getBytes()

     */

    private static byte[] convertToBytes(char[] pass) {

        if (enc == null) {

            synchronized (Password.class) {

                enc = sun.misc.SharedSecrets.getJavaIOAccess()

                        .charset()

                        .newEncoder()

                        .onMalformedInput(CodingErrorAction.REPLACE)

                        .onUnmappableCharacter(CodingErrorAction.REPLACE);

            }

        }

        byte[] ba = new byte[(int)(enc.maxBytesPerChar() * pass.length)];

        ByteBuffer bb = ByteBuffer.wrap(ba);

        synchronized (enc) {

            enc.reset().encode(CharBuffer.wrap(pass), bb, true);

        }

        if (bb.position() < ba.length) {

            ba[bb.position()] = '\n';

        }

        return ba;

    }

    private static volatile CharsetEncoder enc;

}