PC World Komputer 1995 November/PCWK1195.iso/inne/win95/sieciowe/hotja32.lzh/hotjava/classsrc/net/www/auth/basic.java

Text File | 1995-08-11 | 5KB | 195 lines

/*
 * @(#)basic.java    1.8 95/05/12 Jonathan Payne
 *
 * Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

package net.www.auth;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

/**
 *  From RFC 1421
 *
 * @version 1.8 12 May 1995
 * @author Jonathan Payne
*
 * This class has a lowercase name because we usually create an
 * instance of it by catenating the name of the current
 * authentication type with the package name.  In order to guarantee
 * a consistent pattern we always convert the authentication type to
 * lower case.
 */
public class basic extends Authenticator {
    static private byte six2print[] = {
    'A','B','C','D','E','F','G','H','I','J','K','L','M',
    'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
    'a','b','c','d','e','f','g','h','i','j','k','l','m',
    'n','o','p','q','r','s','t','u','v','w','x','y','z',
    '0','1','2','3','4','5','6','7','8','9','+','/'
    };

    static private byte print2six[] = new byte[128];
    static final int    ILLEGAL = -1;

    static {
    int i, limit;

    limit = six2print.length;

    for (i = print2six.length; --i >= 0; ) {
        print2six[i] = (byte) ILLEGAL;
    }

    for (i = 0; --limit >= 0; i++) {
        print2six[six2print[i]] = (byte) i;
    }
    }

    public void encrypt(InputStream is, OutputStream os) {
    int chunk;
    int c = -1;
    int lineCnt = 64;
    int shift;

loop:
    do {
        shift = 24;
        chunk = 0;

        while ((shift -= 8) >= 0) {
        switch (c = is.read()) {
        case -1:
            break loop;

        default:
            chunk |= (c << shift);
            break;
        }
        }
        shift = 24;
        while ((shift -= 6) >= 0) {
        os.write(six2print[(chunk >> shift) & 0x3f]);
        }
        if ((lineCnt -= 4) == 0) {
        os.write('\n');
        lineCnt = 64;
        }
    } while (true);

    switch (shift) {
    case 16:    /* 0 bits left to process */
        break;

    case 8:        /* 8 bits (1 byte) left to process */
        os.write(six2print[(chunk >> 18) & 0x3f]);
        os.write(six2print[(chunk >> 12) & 0x3f]);
        os.write('=');
        os.write('=');
        break;

    case 0:        /* 16 bits (2 bytes) left to process */
        os.write(six2print[(chunk >> 18) & 0x3f]);
        os.write(six2print[(chunk >> 12) & 0x3f]);
        os.write(six2print[(chunk >> 6) & 0x3f]);
        os.write('=');
        break;
    }
    }

    public void decrypt(InputStream is, OutputStream os) {
    int c;
    int shift;
    int chunk;
    int charCnt = 64;

loop:
    do {
        shift = 24;
        chunk = 0;
        while ((shift -= 6) >= 0) {
        switch (c = is.read()) {
        case '=':
            break loop;

        case '\n':
            if (charCnt == 0) {
            charCnt = 64;
            continue loop;
            }
            throw new Exception("Invalid encryption");

        case -1:
            if (shift == 18) {
            throw new Exception("Invalid encryption");
            }
            break loop;

        default:
            {
            int cc = print2six[c];

            switch (cc) {
            case ILLEGAL:
                throw new Exception("Invalid encryption");

            default:
                chunk |= (cc << shift);
                break;
            }
            }
            break;
        }
        }
        shift = 24;
        while ((shift -= 8) >= 0) {
        os.write((chunk >> shift) & 0xff);
        }
        charCnt -= 4;
    } while (true);

    switch (shift) {
    case 18:    /* nothing to process */
        break;

    case 12:    /* one 6 bit entity is illegal */
        throw new Exception("Invalid encryption");

    case 6:        /* two 6 bit entities = one 8 bit byte */
        os.write((chunk >> 16) & 0xff);
        break;

    case 0:
        os.write((chunk >> 16) & 0xff);
        os.write(chunk & 0xff);
        break;
    }
    }

    static public void main(String args[]) {
    Authenticator a = new basic();
    FileOutputStream os = new FileOutputStream("/home/jpayne/livejava/test.uu");

    a.encrypt(new FileInputStream("/home/jpayne/livejava/test.ascii"), os);
    os.close();
    a.decrypt(new FileInputStream("/home/jpayne/livejava/test.uu"), System.out);
    System.out.flush();
    }
}