Usenet 1994 October/usenetsourcesnewsgroupsinfomagicoctober1994disk2.iso/misc/volume1/8711/microemacs-3.9/2

Text File | 1987-11-17 | 28KB | 989 lines

Article 78 of comp.sources.misc:
Path: tut!osu-cis!cbosgd!mandrill!hal!ncoast!allbery
From: [e-mail] (Daniel Lawrence)
Newsgroups: comp.sources.misc
Subject: MicroEmacs 3.9 (Part 2 of 16)
Message-ID: <[e-mail]>
Date: 14 Nov 87 21:06:32 GMT
Sender: [e-mail]
Lines: 974
Approved: [e-mail]
X-Archive: comp.sources.misc/microemacs-3.9/1

# This is a shar archive.
# Remove everything above this line.
# Run the file through sh, not csh.
# (type `sh mes.2')
# If you do not see the message
#    `mes.2 completed!'
# then the file was incomplete.
echo extracting - buffer.c
sed 's/^X//' > buffer.c << 'FRIDAY_NIGHT'
X/*
X * Buffer management.
X * Some of the functions are internal,
X * and some are actually attached to user
X * keys. Like everyone else, they set hints
X * for the display system.
X */
X#include        <stdio.h>
X#include    "estruct.h"
X#include        "edef.h"
X
X/*
X * Attach a buffer to a window. The
X * values of dot and mark come from the buffer
X * if the use count is 0. Otherwise, they come
X * from some other window.
X */
Xusebuffer(f, n)
X{
X        register BUFFER *bp;
X        register int    s;
X        char            bufn[NBUFN];
X
X        if ((s=mlreply("Use buffer: ", bufn, NBUFN)) != TRUE)
X                return (s);
X        if ((bp=bfind(bufn, TRUE, 0)) == NULL)
X                return (FALSE);
X    return(swbuffer(bp));
X}
X
Xnextbuffer(f, n)    /* switch to the next buffer in the buffer list */
X
Xint f, n;    /* default flag, numeric argument */
X{
X    register BUFFER *bp;    /* eligable buffer to switch to*/
X    register BUFFER *bbp;    /* eligable buffer to switch to*/
X
X    /* make sure the arg is legit */
X    if (f == FALSE)
X        n = 1;
X    if (n < 1)
X        return(FALSE);
X
X    bbp = curbp;
X    while (n-- > 0) {
X        /* advance to the next buffer */
X        bp = bbp->b_bufp;
X
X        /* cycle through the buffers to find an eligable one */
X        while (bp == NULL || bp->b_flag & BFINVS) {
X            if (bp == NULL)
X                bp = bheadp;
X            else
X                bp = bp->b_bufp;
X
X            /* don't get caught in an infinite loop! */
X            if (bp == bbp)
X                return(FALSE);
X
X        }
X
X        bbp = bp;
X    }
X
X    return(swbuffer(bp));
X}
X
Xswbuffer(bp)    /* make buffer BP current */
X
XBUFFER *bp;
X
X{
X        register WINDOW *wp;
X
X        if (--curbp->b_nwnd == 0) {             /* Last use.            */
X                curbp->b_dotp  = curwp->w_dotp;
X                curbp->b_doto  = curwp->w_doto;
X                curbp->b_markp = curwp->w_markp;
X                curbp->b_marko = curwp->w_marko;
X        }
X        curbp = bp;                             /* Switch.              */
X    if (curbp->b_active != TRUE) {        /* buffer not active yet*/
X        /* read it in and activate it */
X        readin(curbp->b_fname, TRUE);
X        curbp->b_dotp = lforw(curbp->b_linep);
X        curbp->b_doto = 0;
X        curbp->b_active = TRUE;
X    }
X        curwp->w_bufp  = bp;
X        curwp->w_linep = bp->b_linep;           /* For macros, ignored. */
X        curwp->w_flag |= WFMODE|WFFORCE|WFHARD; /* Quite nasty.         */
X        if (bp->b_nwnd++ == 0) {                /* First use.           */
X                curwp->w_dotp  = bp->b_dotp;
X                curwp->w_doto  = bp->b_doto;
X                curwp->w_markp = bp->b_markp;
X                curwp->w_marko = bp->b_marko;
X                return (TRUE);
X        }
X        wp = wheadp;                            /* Look for old.        */
X        while (wp != NULL) {
X                if (wp!=curwp && wp->w_bufp==bp) {
X                        curwp->w_dotp  = wp->w_dotp;
X                        curwp->w_doto  = wp->w_doto;
X                        curwp->w_markp = wp->w_markp;
X                        curwp->w_marko = wp->w_marko;
X                        break;
X                }
X                wp = wp->w_wndp;
X        }
X        return (TRUE);
X}
X
X/*
X * Dispose of a buffer, by name.
X * Ask for the name. Look it up (don't get too
X * upset if it isn't there at all!). Get quite upset
X * if the buffer is being displayed. Clear the buffer (ask
X * if the buffer has been changed). Then free the header
X * line and the buffer header. Bound to "C-X K".
X */
Xkillbuffer(f, n)
X
X{
X    register BUFFER *bp;
X        register int    s;
X        char bufn[NBUFN];
X
X        if ((s=mlreply("Kill buffer: ", bufn, NBUFN)) != TRUE)
X                return(s);
X        if ((bp=bfind(bufn, FALSE, 0)) == NULL) /* Easy if unknown.     */
X                return (TRUE);
X    if(bp->b_flag & BFINVS)        /* Deal with special buffers    */
X            return (TRUE);        /* by doing nothing.    */
X    return(zotbuf(bp));
X}
X
Xzotbuf(bp)    /* kill the buffer pointed to by bp */
X
Xregister BUFFER *bp;
X
X{
X        register BUFFER *bp1;
X        register BUFFER *bp2;
X        register int    s;
X
X        if (bp->b_nwnd != 0) {                  /* Error if on screen.  */
X                mlwrite("Buffer is being displayed");
X                return (FALSE);
X        }
X        if ((s=bclear(bp)) != TRUE)             /* Blow text away.      */
X                return (s);
X        free((char *) bp->b_linep);             /* Release header line. */
X        bp1 = NULL;                             /* Find the header.     */
X        bp2 = bheadp;
X        while (bp2 != bp) {
X                bp1 = bp2;
X                bp2 = bp2->b_bufp;
X        }
X        bp2 = bp2->b_bufp;                      /* Next one in chain.   */
X        if (bp1 == NULL)                        /* Unlink it.           */
X                bheadp = bp2;
X        else
X                bp1->b_bufp = bp2;
X        free((char *) bp);                      /* Release buffer block */
X        return (TRUE);
X}
X
Xnamebuffer(f,n)        /*    Rename the current buffer    */
X
Xint f, n;        /* default Flag & Numeric arg */
X
X{
X    register BUFFER *bp;    /* pointer to scan through all buffers */
X    char bufn[NBUFN];    /* buffer to hold buffer name */
X
X    /* prompt for and get the new buffer name */
Xask:    if (mlreply("Change buffer name to: ", bufn, NBUFN) != TRUE)
X        return(FALSE);
X
X    /* and check for duplicates */
X    bp = bheadp;
X    while (bp != NULL) {
X        if (bp != curbp) {
X            /* if the names the same */
X            if (strcmp(bufn, bp->b_bname) == 0)
X                goto ask;  /* try again */
X        }
X        bp = bp->b_bufp;    /* onward */
X    }
X
X    strcpy(curbp->b_bname, bufn);    /* copy buffer name to structure */
X    curwp->w_flag |= WFMODE;    /* make mode line replot */
X    mlerase();
X    return(TRUE);
X}
X
X/*
X    List all of the active buffers.  First update the special
X    buffer that holds the list.  Next make sure at least 1
X    window is displaying the buffer list, splitting the screen
X    if this is what it takes.  Lastly, repaint all of the
X    windows that are displaying the list.  Bound to "C-X C-B".
X    A numeric argument forces it to list invisable buffers as
X    well.
X*/
X
Xlistbuffers(f, n)
X{
X        register WINDOW *wp;
X        register BUFFER *bp;
X        register int    s;
X
X        if ((s=makelist(f)) != TRUE)
X                return (s);
X        if (blistp->b_nwnd == 0) {              /* Not on screen yet.   */
X                if ((wp=wpopup()) == NULL)
X                        return (FALSE);
X                bp = wp->w_bufp;
X                if (--bp->b_nwnd == 0) {
X                        bp->b_dotp  = wp->w_dotp;
X                        bp->b_doto  = wp->w_doto;
X                        bp->b_markp = wp->w_markp;
X                        bp->b_marko = wp->w_marko;
X                }
X                wp->w_bufp  = blistp;
X                ++blistp->b_nwnd;
X        }
X        wp = wheadp;
X        while (wp != NULL) {
X                if (wp->w_bufp == blistp) {
X                        wp->w_linep = lforw(blistp->b_linep);
X                        wp->w_dotp  = lforw(blistp->b_linep);
X                        wp->w_doto  = 0;
X                        wp->w_markp = NULL;
X                        wp->w_marko = 0;
X                        wp->w_flag |= WFMODE|WFHARD;
X                }
X                wp = wp->w_wndp;
X        }
X        return (TRUE);
X}
X
X/*
X * This routine rebuilds the
X * text in the special secret buffer
X * that holds the buffer list. It is called
X * by the list buffers command. Return TRUE
X * if everything works. Return FALSE if there
X * is an error (if there is no memory). Iflag
X * indecates weather to list hidden buffers.
X */
Xmakelist(iflag)
X
Xint iflag;    /* list hidden buffer flag */
X
X{
X        register char   *cp1;
X        register char   *cp2;
X        register int    c;
X        register BUFFER *bp;
X        register LINE   *lp;
X        register int    s;
X    register int    i;
X        long nbytes;        /* # of bytes in current buffer */
X        char b[7+1];
X        char line[128];
X
X        blistp->b_flag &= ~BFCHG;               /* Don't complain!      */
X        if ((s=bclear(blistp)) != TRUE)         /* Blow old text away   */
X                return (s);
X        strcpy(blistp->b_fname, "");
X        if (addline("ACT MODES        Size Buffer        File") == FALSE
X        ||  addline("--- -----        ---- ------        ----") == FALSE)
X                return (FALSE);
X        bp = bheadp;                            /* For all buffers      */
X
X    /* build line to report global mode settings */
X    cp1 = &line[0];
X    *cp1++ = ' ';
X    *cp1++ = ' ';
X    *cp1++ = ' ';
X    *cp1++ = ' ';
X
X    /* output the mode codes */
X    for (i = 0; i < NUMMODES; i++)
X        if (gmode & (1 << i))
X            *cp1++ = modecode[i];
X        else
X            *cp1++ = '.';
X    strcpy(cp1, "         Global Modes");
X    if (addline(line) == FALSE)
X        return(FALSE);
X
X    /* output the list of buffers */
X        while (bp != NULL) {
X        /* skip invisable buffers if iflag is false */
X                if (((bp->b_flag&BFINVS) != 0) && (iflag != TRUE)) {
X                        bp = bp->b_bufp;
X                        continue;
X                }
X                cp1 = &line[0];                 /* Start at left edge   */
X
X        /* output status of ACTIVE flag (has the file been read in? */
X                if (bp->b_active == TRUE)    /* "@" if activated       */
X                        *cp1++ = '@';
X                else
X                        *cp1++ = ' ';
X
X        /* output status of changed flag */
X                if ((bp->b_flag&BFCHG) != 0)    /* "*" if changed       */
X                        *cp1++ = '*';
X                else
X                        *cp1++ = ' ';
X
X        /* report if the file is truncated */
X                if ((bp->b_flag&BFTRUNC) != 0)
X                        *cp1++ = '#';
X                else
X                        *cp1++ = ' ';
X
X                *cp1++ = ' ';    /* space */
X
X        /* output the mode codes */
X        for (i = 0; i < NUMMODES; i++) {
X            if (bp->b_mode & (1 << i))
X                *cp1++ = modecode[i];
X            else
X                *cp1++ = '.';
X        }
X                *cp1++ = ' ';                   /* Gap.                 */
X                nbytes = 0L;                    /* Count bytes in buf.  */
X                lp = lforw(bp->b_linep);
X                while (lp != bp->b_linep) {
X                        nbytes += (long)llength(lp)+1L;
X                        lp = lforw(lp);
X                }
X                ltoa(b, 7, nbytes);             /* 6 digit buffer size. */
X                cp2 = &b[0];
X                while ((c = *cp2++) != 0)
X                        *cp1++ = c;
X                *cp1++ = ' ';                   /* Gap.                 */
X                cp2 = &bp->b_bname[0];          /* Buffer name          */
X                while ((c = *cp2++) != 0)
X                        *cp1++ = c;
X                cp2 = &bp->b_fname[0];          /* File name            */
X                if (*cp2 != 0) {
X                        while (cp1 < &line[3+1+5+1+6+4+NBUFN])
X                                *cp1++ = ' ';
X                        while ((c = *cp2++) != 0) {
X                                if (cp1 < &line[128-1])
X                                        *cp1++ = c;
X                        }
X                }
X                *cp1 = 0;                       /* Add to the buffer.   */
X                if (addline(line) == FALSE)
X                        return (FALSE);
X                bp = bp->b_bufp;
X        }
X        return (TRUE);                          /* All done             */
X}
X
Xltoa(buf, width, num)
X
Xchar   buf[];
Xint    width;
Xlong   num;
X
X{
X        buf[width] = 0;                         /* End of string.       */
X        while (num >= 10) {                     /* Conditional digits.  */
X                buf[--width] = (int)(num%10L) + '0';
X                num /= 10L;
X        }
X        buf[--width] = (int)num + '0';          /* Always 1 digit.      */
X        while (width != 0)                      /* Pad with blanks.     */
X                buf[--width] = ' ';
X}
X
X/*
X * The argument "text" points to
X * a string. Append this line to the
X * buffer list buffer. Handcraft the EOL
X * on the end. Return TRUE if it worked and
X * FALSE if you ran out of room.
X */
Xaddline(text)
Xchar    *text;
X{
X        register LINE   *lp;
X        register int    i;
X        register int    ntext;
X
X        ntext = strlen(text);
X        if ((lp=lalloc(ntext)) == NULL)
X                return (FALSE);
X        for (i=0; i<ntext; ++i)
X                lputc(lp, i, text[i]);
X        blistp->b_linep->l_bp->l_fp = lp;       /* Hook onto the end    */
X        lp->l_bp = blistp->b_linep->l_bp;
X        blistp->b_linep->l_bp = lp;
X        lp->l_fp = blistp->b_linep;
X        if (blistp->b_dotp == blistp->b_linep)  /* If "." is at the end */
X                blistp->b_dotp = lp;            /* move it to new line  */
X        return (TRUE);
X}
X
X/*
X * Look through the list of
X * buffers. Return TRUE if there
X * are any changed buffers. Buffers
X * that hold magic internal stuff are
X * not considered; who cares if the
X * list of buffer names is hacked.
X * Return FALSE if no buffers
X * have been changed.
X */
Xanycb()
X{
X        register BUFFER *bp;
X
X        bp = bheadp;
X        while (bp != NULL) {
X                if ((bp->b_flag&BFINVS)==0 && (bp->b_flag&BFCHG)!=0)
X                        return (TRUE);
X                bp = bp->b_bufp;
X        }
X        return (FALSE);
X}
X
X/*
X * Find a buffer, by name. Return a pointer
X * to the BUFFER structure associated with it.
X * If the buffer is not found
X * and the "cflag" is TRUE, create it. The "bflag" is
X * the settings for the flags in in buffer.
X */
XBUFFER  *
Xbfind(bname, cflag, bflag)
Xregister char   *bname;
X{
X        register BUFFER *bp;
X    register BUFFER *sb;    /* buffer to insert after */
X        register LINE   *lp;
X    char *malloc();
X
X        bp = bheadp;
X        while (bp != NULL) {
X                if (strcmp(bname, bp->b_bname) == 0)
X                        return (bp);
X                bp = bp->b_bufp;
X        }
X        if (cflag != FALSE) {
X                if ((bp=(BUFFER *)malloc(sizeof(BUFFER))) == NULL)
X                        return (NULL);
X                if ((lp=lalloc(0)) == NULL) {
X                        free((char *) bp);
X                        return (NULL);
X                }
X        /* find the place in the list to insert this buffer */
X        if (bheadp == NULL || strcmp(bheadp->b_bname, bname) > 0) {
X            /* insert at the beginning */
X                    bp->b_bufp = bheadp;
X                    bheadp = bp;
X            } else {
X            sb = bheadp;
X            while (sb->b_bufp != NULL) {
X                if (strcmp(sb->b_bufp->b_bname, bname) > 0)
X                    break;
X                sb = sb->b_bufp;
X            }
X
X            /* and insert it */
X                   bp->b_bufp = sb->b_bufp;
X                sb->b_bufp = bp;
X               }
X
X        /* and set up the other buffer fields */
X        bp->b_active = TRUE;
X                bp->b_dotp  = lp;
X                bp->b_doto  = 0;
X                bp->b_markp = NULL;
X                bp->b_marko = 0;
X                bp->b_flag  = bflag;
X        bp->b_mode  = gmode;
X                bp->b_nwnd  = 0;
X                bp->b_linep = lp;
X                strcpy(bp->b_fname, "");
X                strcpy(bp->b_bname, bname);
X#if    CRYPT
X        bp->b_key[0] = 0;
X#endif
X                lp->l_fp = lp;
X                lp->l_bp = lp;
X        }
X        return (bp);
X}
X
X/*
X * This routine blows away all of the text
X * in a buffer. If the buffer is marked as changed
X * then we ask if it is ok to blow it away; this is
X * to save the user the grief of losing text. The
X * window chain is nearly always wrong if this gets
X * called; the caller must arrange for the updates
X * that are required. Return TRUE if everything
X * looks good.
X */
Xbclear(bp)
Xregister BUFFER *bp;
X{
X        register LINE   *lp;
X        register int    s;
X
X        if ((bp->b_flag&BFINVS) == 0            /* Not scratch buffer.  */
X        && (bp->b_flag&BFCHG) != 0              /* Something changed    */
X        && (s=mlyesno("Discard changes")) != TRUE)
X                return (s);
X        bp->b_flag  &= ~BFCHG;                  /* Not changed          */
X        while ((lp=lforw(bp->b_linep)) != bp->b_linep)
X                lfree(lp);
X        bp->b_dotp  = bp->b_linep;              /* Fix "."              */
X        bp->b_doto  = 0;
X        bp->b_markp = NULL;                     /* Invalidate "mark"    */
X        bp->b_marko = 0;
X        return (TRUE);
X}
X
Xunmark(f, n)    /* unmark the current buffers change flag */
X
Xint f, n;    /* unused command arguments */
X
X{
X    curbp->b_flag &= ~BFCHG;
X    curwp->w_flag |= WFMODE;
X    return(TRUE);
X}
FRIDAY_NIGHT
echo extracting - crypt.c
sed 's/^X//' > crypt.c << 'FRIDAY_NIGHT'
X/*    Crypt:    Encryption routines for MicroEMACS
X        written by Dana Hoggatt and Daniel Lawrence
X*/
X
X#include    <stdio.h>
X#include    "estruct.h"
X#include    "edef.h"
X
X#if    CRYPT
Xsetkey(f, n)    /* reset encryption key of current buffer */
X
Xint f;        /* default flag */
Xint n;        /* numeric argument */
X
X{
X    register int status;    /* return status */
X    int odisinp;        /* original vlaue of disinp */
X    char key[NPAT];        /* new encryption string */
X
X    /* turn command input echo off */
X    odisinp = disinp;
X    disinp = FALSE;
X
X    /* get the string to use as an encrytion string */
X    status = mlreply("Encryption String: ", key, NPAT - 1);
X    disinp = odisinp;
X        if (status != TRUE)
X                return(status);
X
X    /* and encrypt it */
X    crypt((char *)NULL, 0);
X    crypt(key, strlen(key));
X
X    /* and save it off */
X    strcpy(curbp->b_key, key);
X    mlwrite(" ");        /* clear it off the bottom line */
X    return(TRUE);
X}
X
X/**********
X *
X *    crypt - in place encryption/decryption of a buffer
X *
X *    (C) Copyright 1986, Dana L. Hoggatt
X *    1216, Beck Lane, Lafayette, IN
X *
X *    When consulting directly with the author of this routine,
X *    please refer to this routine as the "DLH-POLY-86-B CIPHER".
X *
X *    This routine was written for Dan Lawrence, for use in V3.8 of
X *    MicroEMACS, a public domain text/program editor.
X *
X *    I kept the following goals in mind when preparing this function:
X *
X *        1.    All printable characters were to be encrypted back
X *        into the printable range, control characters and
X *        high-bit characters were to remain unaffected.  this
X *        way, encrypted would still be just as cheap to
X *        transmit down a 7-bit data path as they were before.
X *
X *        2.    The encryption had to be portable.  The encrypted
X *        file from one computer should be able to be decrypted
X *        on another computer.
X *
X *        3.    The encryption had to be inexpensive, both in terms
X *        of speed and space.
X *
X *        4.    The system needed to be secure against all but the
X *        most determined of attackers.
X *
X *    For encryption of a block of data, one calls crypt passing
X *    a pointer to the data block and its length. The data block is
X *    encrypted in place, that is, the encrypted output overwrites
X *    the input.  Decryption is totally isomorphic, and is performed
X *    in the same manner by the same routine.
X *
X *    Before using this routine for encrypting data, you are expected
X *    to specify an encryption key.  This key is an arbitrary string,
X *    to be supplied by the user.  To set the key takes two calls to
X *    crypt().  First, you call
X *
X *        crypt(NULL, vector)
X *
X *    This resets all internal control information.  Typically (and
X *    specifically in the case on MICRO-emacs) you would use a "vector"
X *    of 0.  Other values can be used to customize your editor to be
X *    "incompatable" with the normally distributed version.  For
X *    this purpose, the best results will be obtained by avoiding
X *    multiples of 95.
X *
X *    Then, you "encrypt" your password by calling
X *
X *        crypt(pass, strlen(pass))
X *
X *    where "pass" is your password string.  Crypt() will destroy
X *    the original copy of the password (it becomes encrypted),
X *    which is good.  You do not want someone on a multiuser system
X *    to peruse your memory space and bump into your password.
X *    Still, it is a better idea to erase the password buffer to
X *    defeat memory perusal by a more technical snooper.
X *
X *    For the interest of cryptologists, at the heart of this
X *    function is a Beaufort Cipher.  The cipher alphabet is the
X *    range of printable characters (' ' to '~'), all "control"
X *    and "high-bit" characters are left unaltered.
X *
X *    The key is a variant autokey, derived from a wieghted sum
X *    of all the previous clear text and cipher text.  A counter
X *    is used as salt to obiterate any simple cyclic behavior
X *    from the clear text, and key feedback is used to assure
X *    that the entire message is based on the original key,
X *    preventing attacks on the last part of the message as if
X *    it were a pure autokey system.
X *
X *    Overall security of encrypted data depends upon three
X *    factors:  the fundamental cryptographic system must be
X *    difficult to compromise; exhaustive searching of the key
X *    space must be computationally expensive; keys and plaintext
X *    must remain out of sight.  This system satisfies this set
X *    of conditions to within the degree desired for MicroEMACS.
X *
X *    Though direct methods of attack (against systems such as
X *    this) do exist, they are not well known and will consume
X *    considerable amounts of computing time.  An exhaustive
X *    search requires over a billion investigations, on average.
X *
X *    The choice, entry, storage, manipulation, alteration,
X *    protection and security of the keys themselves are the
X *    responsiblity of the user.
X *
X **********/
X
Xcrypt(bptr, len)
Xregister char *bptr;    /* buffer of characters to be encrypted */
Xregister unsigned len;    /* number of characters in the buffer */
X{
X    register int cc;    /* current character being considered */
X
X    static long key = 0;    /* 29 bit encipherment key */
X    static int salt = 0;    /* salt to spice up key with */
X
X    if (!bptr) {        /* is there anything here to encrypt? */
X        key = len;    /* set the new key */
X        salt = len;    /* set the new salt */
X        return;
X    }
X    while (len--) {        /* for every character in the buffer */
X
X        cc = *bptr;    /* get a character out of the buffer */
X
X        /* only encipher printable characters */
X        if ((cc >= ' ') && (cc <= '~')) {
X
X/**  If the upper bit (bit 29) is set, feed it back into the key.  This
X    assures us that the starting key affects the entire message.  **/
X
X            key &= 0x1FFFFFFFL;    /* strip off overflow */
X            if (key & 0x10000000L) {
X                key ^= 0x0040A001L;    /* feedback */
X            }
X
X/**  Down-bias the character, perform a Beaufort encipherment, and
X    up-bias the character again.  We want key to be positive
X    so that the left shift here will be more portable and the
X    mod95() faster   **/
X
X            cc = mod95((int)(key % 95) - (cc - ' ')) + ' ';
X
X/**  the salt will spice up the key a little bit, helping to obscure
X    any patterns in the clear text, particularly when all the
X    characters (or long sequences of them) are the same.  We do
X    not want the salt to go negative, or it will affect the key
X    too radically.  It is always a good idea to chop off cyclics
X    to prime values.  **/
X
X            if (++salt >= 20857) {    /* prime modulus */
X                salt = 0;
X            }
X
X/**  our autokey (a special case of the running key) is being
X    generated by a wieghted checksum of clear text, cipher
X    text, and salt.   **/
X
X            key = key + key + cc + *bptr + salt;
X        }
X        *bptr++ = cc;    /* put character back into buffer */
X    }
X    return;
X}
X
Xstatic int mod95(val)
X
Xregister int val;
X
X{
X    /*  The mathematical MOD does not match the computer MOD  */
X
X    /*  Yes, what I do here may look strange, but it gets the
X        job done, and portably at that.  */
X
X    while (val >= 9500)
X        val -= 9500;
X    while (val >= 950)
X        val -= 950;
X    while (val >= 95)
X        val -= 95;
X    while (val < 0)
X        val += 95;
X    return (val);
X}
X#else
Xnocrypt()
X{
X}
X#endif
FRIDAY_NIGHT
echo extracting - dg10.c
sed 's/^X//' > dg10.c << 'FRIDAY_NIGHT'
X/*
X * The routines in this file provide support for the Data General Model 10
X * Microcomputer.
X */
X
X#define    termdef    1            /* don't define "term" external */
X
X#include        <stdio.h>
X#include    "estruct.h"
X#include        "edef.h"
X
X#if     DG10
X
X#define NROW    24                      /* Screen size.                 */
X#define NCOL    80                      /* Edit if you want to.         */
X#define    NPAUSE    100            /* # times thru update to pause */
X#define    MARGIN    8            /* size of minimim margin and    */
X#define    SCRSIZ    64            /* scroll size for extended lines */
X#define BEL     0x07                    /* BEL character.               */
X#define ESC     30                      /* DG10 ESC character.          */
X
Xextern  int     ttopen();               /* Forward references.          */
Xextern  int     ttgetc();
Xextern  int     ttputc();
Xextern  int     ttflush();
Xextern  int     ttclose();
Xextern    int    dg10kopen();
Xextern    int    dg10kclose();
Xextern  int     dg10move();
Xextern  int     dg10eeol();
Xextern  int     dg10eeop();
Xextern  int     dg10beep();
Xextern  int     dg10open();
Xextern    int    dg10rev();
Xextern    int    dg10close();
Xextern    int    dg10cres();
X
X#if    COLOR
Xextern    int    dg10fcol();
Xextern    int    dg10bcol();
X
Xint    cfcolor = -1;        /* current forground color */
Xint    cbcolor = -1;        /* current background color */
Xint    ctrans[] = {        /* emacs -> DG10 color translation table */
X    0, 4, 2, 6, 1, 5, 3, 7};
X#endif
X
X/*
X * Standard terminal interface dispatch table. Most of the fields point into
X * "termio" code.
X */
XTERM    term    = {
X    NROW-1,
X        NROW-1,
X        NCOL,
X        NCOL,
X    MARGIN,
X    SCRSIZ,
X    NPAUSE,
X        dg10open,
X        dg10close,
X    dg10kopen,
X    dg10kclose,
X        ttgetc,
X        ttputc,
X        ttflush,
X        dg10move,
X        dg10eeol,
X        dg10eeop,
X        dg10beep,
X    dg10rev,
X    dg10cres
X#if    COLOR
X    , dg10fcol,
X    dg10bcol
X#endif
X};
X
X#if    COLOR
Xdg10fcol(color)        /* set the current output color */
X
Xint color;    /* color to set */
X
X{
X    if (color == cfcolor)
X        return;
X    ttputc(ESC);
X    ttputc(0101);
X    ttputc(ctrans[color]);
X    cfcolor = color;
X}
X
Xdg10bcol(color)        /* set the current background color */
X
Xint color;    /* color to set */
X
X{
X    if (color == cbcolor)
X        return;
X    ttputc(ESC);
X    ttputc(0102);
X    ttputc(ctrans[color]);
X        cbcolor = color;
X}
X#endif
X
Xdg10move(row, col)
X{
X    ttputc(16);
X        ttputc(col);
X    ttputc(row);
X}
X
Xdg10eeol()
X{
X        ttputc(11);
X}
X
Xdg10eeop()
X{
X#if    COLOR
X    dg10fcol(gfcolor);
X    dg10bcol(gbcolor);
X#endif
X        ttputc(ESC);
X        ttputc(0106);
X        ttputc(0106);
X}
X
Xdg10rev(state)        /* change reverse video state */
X
Xint state;    /* TRUE = reverse, FALSE = normal */
X
X{
X#if    COLOR
X    if (state == TRUE) {
X        dg10fcol(0);
X        dg10bcol(7);
X    }
X#else
X    ttputc(ESC);
X    ttputc(state ? 0104: 0105);
X#endif
X}
X
Xdg10cres()    /* change screen resolution */
X
X{
X    return(TRUE);
X}
X
Xspal()        /* change palette string */
X
X{
X    /*    Does nothing here    */
X}
X
Xdg10beep()
X{
X        ttputc(BEL);
X        ttflush();
X}
X
Xdg10open()
X{
X    strcpy(sres, "NORMAL");
X    revexist = TRUE;
X        ttopen();
X}
X
Xdg10close()
X
X{
X#if    COLOR
X    dg10fcol(7);
X    dg10bcol(0);
X#endif
X    ttclose();
X}
X
Xdg10kopen()
X
X{
X}
X
Xdg10kclose()
X
X{
X}
X
X#if    FLABEL
Xfnclabel(f, n)        /* label a function key */
X
Xint f,n;    /* default flag, numeric argument [unused] */
X
X{
X    /* on machines with no function keys...don't bother */
X    return(TRUE);
X}
X#endif
X#else
Xdg10hello()
X{
X}
X#endif
FRIDAY_NIGHT
echo mes.2 completed!
# That's all folks!