/*

 * Copyright (c) 2005, 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 sun.security.jgss;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.IOException;

import java.io.EOFException;

import sun.security.util.*;

/**

 * Utilities for processing GSS Tokens.

 *

 */

public abstract class GSSToken {

    /**

     * Copies an integer value to a byte array in little endian form.

     * @param value the integer value to write

     * @param array the byte array into which the integer must be copied. It

     * is assumed that the array will be large enough to hold the 4 bytes of

     * the integer.

     */

    public static final void writeLittleEndian(int value, byte[] array) {

        writeLittleEndian(value, array, 0);

    }

    /**

     * Copies an integer value to a byte array in little endian form.

     * @param value the integer value to write

     * @param array the byte array into which the integer must be copied. It

     * is assumed that the array will be large enough to hold the 4 bytes of

     * the integer.

     * @param pos the position at which to start writing

     */

    public static final void writeLittleEndian(int value, byte[] array,

                                               int pos) {

        array[pos++] = (byte)(value);

        array[pos++] = (byte)((value>>>8));

        array[pos++] = (byte)((value>>>16));

        array[pos++] = (byte)((value>>>24));

    }

    public static final void writeBigEndian(int value, byte[] array) {

        writeBigEndian(value, array, 0);

    }

    public static final void writeBigEndian(int value, byte[] array,

                                               int pos) {

        array[pos++] = (byte)((value>>>24));

        array[pos++] = (byte)((value>>>16));

        array[pos++] = (byte)((value>>>8));

        array[pos++] = (byte)(value);

    }

    /**

     * Reads an integer value from a byte array in little endian form. This

     * method allows the reading of two byte values as well as four bytes

     * values both of which are needed in the Kerberos v5 GSS-API mechanism.

     *

     * @param data the array containing the bytes of the integer value

     * @param pos the offset in the array

     * @size the number of bytes to read from the array.

     * @return the integer value

     */

    public static final int readLittleEndian(byte[] data, int pos, int size) {

        int retVal = 0;

        int shifter = 0;

        while (size > 0) {

            retVal += (data[pos] & 0xff) << shifter;

            shifter += 8;

            pos++;

            size--;

        }

        return retVal;

    }

    public static final int readBigEndian(byte[] data, int pos, int size) {

        int retVal = 0;

        int shifter = (size-1)*8;

        while (size > 0) {

            retVal += (data[pos] & 0xff) << shifter;

            shifter -= 8;

            pos++;

            size--;

        }

        return retVal;

    }

    /**

     * Writes a two byte integer value to a OutputStream.

     *

     * @param val the integer value. It will lose the high-order two bytes.

     * @param os the OutputStream to write to

     * @throws IOException if an error occurs while writing to the OutputStream

     */

    public static final void writeInt(int val, OutputStream os)

        throws IOException {

        os.write(val>>>8);

        os.write(val);

    }

    /**

     * Writes a two byte integer value to a byte array.

     *

     * @param val the integer value. It will lose the high-order two bytes.

     * @param dest the byte array to write to

     * @param pos the offset to start writing to

     */

    public static final int writeInt(int val, byte[] dest, int pos) {

        dest[pos++] = (byte)(val>>>8);

        dest[pos++] = (byte)val;

        return pos;

    }

    /**

     * Reads a two byte integer value from an InputStream.

     *

     * @param is the InputStream to read from

     * @returns the integer value

     * @throws IOException if some errors occurs while reading the integer

     * bytes.

     */

    public static final int readInt(InputStream is) throws IOException {

        return (((0xFF & is.read()) << 8)

                 | (0xFF & is.read()));

    }

    /**

     * Reads a two byte integer value from a byte array.

     *

     * @param src the byte arra to read from

     * @param pos the offset to start reading from

     * @returns the integer value

     */

    public static final int readInt(byte[] src, int pos) {

        return ((0xFF & src[pos])<<8 | (0xFF & src[pos+1]));

    }

    /**

     * Blocks till the required number of bytes have been read from the

     * input stream.

     *

     * @param is the InputStream to read from

     * @param buffer the buffer to store the bytes into

     * @param throws EOFException if EOF is reached before all bytes are

     * read.

     * @throws IOException is an error occurs while reading

     */

    public static final void readFully(InputStream is, byte[] buffer)

        throws IOException {

        readFully(is, buffer, 0, buffer.length);

    }

    /**

     * Blocks till the required number of bytes have been read from the

     * input stream.

     *

     * @param is the InputStream to read from

     * @param buffer the buffer to store the bytes into

     * @param offset the offset to start storing at

     * @param len the number of bytes to read

     * @param throws EOFException if EOF is reached before all bytes are

     * read.

     * @throws IOException is an error occurs while reading

     */

    public static final void readFully(InputStream is,

                                       byte[] buffer, int offset, int len)

        throws IOException {

        int temp;

        while (len > 0) {

            temp = is.read(buffer, offset, len);

            if (temp == -1)

                throw new EOFException("Cannot read all "

                                       + len

                                       + " bytes needed to form this token!");

            offset += temp;

            len -= temp;

        }

    }

    public static final void debug(String str) {

        System.err.print(str);

    }

    public static final  String getHexBytes(byte[] bytes) {

        return getHexBytes(bytes, 0, bytes.length);

    }

    public static final  String getHexBytes(byte[] bytes, int len) {

        return getHexBytes(bytes, 0, len);

    }

    public static final String getHexBytes(byte[] bytes, int pos, int len) {

        StringBuffer sb = new StringBuffer();

        for (int i = pos; i < (pos+len); i++) {

            int b1 = (bytes[i]>>4) & 0x0f;

            int b2 = bytes[i] & 0x0f;

            sb.append(Integer.toHexString(b1));

            sb.append(Integer.toHexString(b2));

            sb.append(' ');

        }

        return sb.toString();

    }

}