/* * Copyright (c) 2000-2001 Sun Microsystems, Inc. All Rights Reserved. */package examples.netclient;/** * This class encodes a user name and password * in the format (base 64) that HTTP Basic * Authorization requires. */class BasicAuth {    // make sure no one can instantiate this class    private BasicAuth() {}    // conversion table    private static byte[] cvtTable = {        (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E',        (byte)'F', (byte)'G', (byte)'H', (byte)'I', (byte)'J',        (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O',        (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T',        (byte)'U', (byte)'V', (byte)'W', (byte)'X', (byte)'Y',        (byte)'Z',        (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e',        (byte)'f', (byte)'g', (byte)'h', (byte)'i', (byte)'j',        (byte)'k', (byte)'l', (byte)'m', (byte)'n', (byte)'o',        (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t',        (byte)'u', (byte)'v', (byte)'w', (byte)'x', (byte)'y',        (byte)'z',        (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4',        (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9',        (byte)'+', (byte)'/'    };    /**     * Encode a name/password pair appropriate to     * use in an HTTP header for Basic Authentication.     *    name     the user's name     *    passwd   the user's password     *    returns  String   the base64 encoded name:password     */    static String encode(String name,                         String passwd) {        byte input[] = (name + ":" + passwd).getBytes();        byte[] output = new byte[((input.length / 3) + 1) * 4];        int ridx = 0;        int chunk = 0;        /**         * Loop through input with 3-byte stride. For         * each 'chunk' of 3-bytes, create a 24-bit         * value, then extract four 6-bit indices.         * Use these indices to extract the base-64         * encoding for this 6-bit 'character'         */        for (int i = 0; i < input.length; i += 3) {            int left = input.length - i;            // have at least three bytes of data left            if (left > 2) {                chunk = (input[i] << 16)|                        (input[i + 1] << 8) |                         input[i + 2];                output[ridx++] = cvtTable[(chunk&0xFC0000)>>18];                output[ridx++] = cvtTable[(chunk&0x3F000) >>12];                output[ridx++] = cvtTable[(chunk&0xFC0)   >> 6];                output[ridx++] = cvtTable[(chunk&0x3F)];            } else if (left == 2) {                // down to 2 bytes. pad with 1 '='                chunk = (input[i] << 16) |                        (input[i + 1] << 8);                output[ridx++] = cvtTable[(chunk&0xFC0000)>>18];                output[ridx++] = cvtTable[(chunk&0x3F000) >>12];                output[ridx++] = cvtTable[(chunk&0xFC0)   >> 6];                output[ridx++] = '=';            } else {                // down to 1 byte. pad with 2 '='                chunk = input[i] << 16;                output[ridx++] = cvtTable[(chunk&0xFC0000)>>18];                output[ridx++] = cvtTable[(chunk&0x3F000) >>12];                output[ridx++] = '=';                output[ridx++] = '=';            }        }        return new String(output);    }}