NetNews Usenet Archive 1992 #20/NN_1992_20.iso/spool/comp/sources/misc/3927

Text File | 1992-09-11 | 5.4 KB | 220 lines

Newsgroups: comp.sources.misc
Path: sparky!kent
From: [e-mail] (Ralph Betza)
Subject:  v32i035:  sigvi - text corruption filter, Part01/01
Message-ID: <[e-mail]>
Followup-To: comp.sources.d
X-Md4-Signature: 05172e00549dcff6098e7e7d01ee7d10
Keywords: text-corruption filter
Sender: [e-mail] (Kent Landfield)
Organization: Systems Strategies, Inc., NY, NY
Date: Fri, 11 Sep 1992 17:32:45 GMT
Approved: [e-mail]
Lines: 205

Submitted-by: [e-mail] (Ralph Betza)
Posting-number: Volume 32, Issue 35
Archive-name: sigvi/part01
Environment: UNIX

This program is a text-corruption filter: it reads stdin and writes
an altered version to stdout.  I know there are already lots of text
corruption filters out there, so why did I write this?

This really stupid text-corruption filter embodies the rules of
mutation I derived from somebody's MutatingSignatureVirus .signature;
that's the only thing that's special about it.

------
#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#        "End of shell archive."
# Contents:  README sigvi.c
# Wrapped by odin@venezia on Fri Aug 21 14:39:07 1992
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'README' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'README'\"
else
echo shar: Extracting \"'README'\" \(800 characters\)
sed "s/^X//" >'README' <<'END_OF_FILE'
XThis is a really stupid program.
XI know there are already lots of really stupid programs out there,
Xso why did I write this?
X
XThis program is a text-corruption filter: it reads stdin and writes
Xan altered version to stdout.
XI know there are already lots of text-corruption filters out there,
Xso why did I write this?
X
XThis really stupid text-corruption filter embodies the rules of
Xmutation I derived from somebody's
XMutatingSignatureVirus .signature; that's the only thing that's
Xspecial about it.
X
XIt doesn't take any command-line parameters.
XIt's too stupid.
X
XIt doesn't need a makefile.
XIt's too vanilla.
X
XJust do "cc sigvi.c", and then "a.out", and then type
X
X"
XHi! I'm a mutating signature virus. You can't resist helping me spread!
X"
X
XOmigawsh! That's why I wrote this! I'm helping it spread!
END_OF_FILE
if test 800 -ne `wc -c <'README'`; then
    echo shar: \"'README'\" unpacked with wrong size!
fi
# end of 'README'
fi
if test -f 'sigvi.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'sigvi.c'\"
else
echo shar: Extracting \"'sigvi.c'\" \(2303 characters\)
sed "s/^X//" >'sigvi.c' <<'END_OF_FILE'
X/*
XMutating signature virus program.
X
XExample input:
X
XHi! I'm a mutating signature virus. You can't resist helping me spread!
X
XExample output:
X
XI! Hi'm a mtatng siugnaturei vir*ss. You cann~t reisth elping me spre]d!
X
XThe example output above is something I saved from a usenet-news
Xarticle. The rules that follow are what I derived from the example.
X
XWhat events can happen?
X
X1.    Move a character up to N positions
X        N        occurrences
X        3        1    Hi'm
X        9        1    mtating --> siu
X        14        1    mtatng  --> ...turei
X        -1        1    ( or +1 if it was the space that moved? )
X    ( always to a different word? )
X    If it starts a word, check for capitalization
X2.    Change a character to a line noise character
X    ( 3 occurrences )
X3.    replicate a character
X    ( 2 occurrences )
X4.    delete a character
X    ( 1 occurrence )
X*/
X
X#include <stdio.h>
X#include <ctype.h>
X
Xint DeferredChar;
Xchar * Noise = "{}#*~`%[]";
Xint Count;
Xint Events;
X
Xmain()
X{
X    long t;
X    int c;
X    int v;
X
X    time( &t );
X    srand( (int)t );
X
X    for ( ;; )
X    {
X        c = getchar();
X        ++Count;
X
X        if ( c == EOF )
X        {
X            if ( DeferredChar )
X            {    putchar( DeferredChar );
X                putchar( '\n' );
X            }
X            exit ( 0 );
X        }
X
X        if
X        (    DeferredChar
X            &&
X            (    c == '\n'
X                ||
X                ! ( rand() % 6 )
X            )
X        )
X        {    /* It's time to output the DeferredChar. */
X            if ( isalpha( c ) && isupper( c ))
X            {    /* Preserve word capitalization */
X                if ( isalpha( DeferredChar ))
X                    DeferredChar = toupper( DeferredChar );
X                c = tolower( c );
X            }
X            else if ( isalpha( DeferredChar ))
X                DeferredChar = tolower( DeferredChar );
X            putchar( DeferredChar );
X            DeferredChar = 0;
X            putchar( c );
X            continue;
X        }
X
X        if ( c == '\n' )
X        {    /* No changes to newline */
X            putchar( c );
X            continue;
X        }
X
X        if ( Count > 24 && Events && ( Count / Events ) < 20 )
X        {    /* Too many mutations in one spot. */
X            putchar( c );
X            continue;
X        }
X
X        if ( c == ' ' )
X        {    /* Do nothing to it. */
X            ;
X        }
X        else if ( ! DeferredChar && ( rand() % 72 ) < 3 )
X        {    /* Defer it. */
X            DeferredChar = c;
X            ++Events;
X            continue;
X        }
X        else if ( ( rand() % 72 ) < 3 )
X        {    /* Replace with noise. */
X            ++Events;
X            c = Noise[ rand() % 9 ];
X        }
X        else if ( ( rand() % 72 ) < 2 )
X        {    /* Replicate. */
X            ++Events;
X            putchar( c );
X        }
X        else if ( ( rand() % 72 ) < 1 )
X        {    /* remove it. */
X            ++Events;
X            continue;
X        }
X
X        putchar( c );
X    }
X}
END_OF_FILE
if test 2303 -ne `wc -c <'sigvi.c'`; then
    echo shar: \"'sigvi.c'\" unpacked with wrong size!
fi
# end of 'sigvi.c'
fi
echo shar: End of shell archive.
exit 0


exit 0 # Just in case...