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Re: Let's go to the movies

by liverpole (Monsignor)
on Apr 11, 2006 at 11:56 UTC ( #542519=note: print w/replies, xml ) Need Help??

in reply to Let's go to the movies

An exremely clever idea! ++

Let me take a crack at deobfuscation ...

Running perl -MO=Deparse doesn't produce anything particularly readable, so I saved it to a file, and put newlines after all the semicolons:
% perl -MO=Deparse movies > movies1 % vi movies1 % cat movies1 $_ = qq[(\$w,\$h)=split/x/,shift||"19x20"; \$q=10+10*\$w; \$r=20+10*\$h; \@m=((31,(15\n )x(\$w-1))x\$h,(31)x\$w); \$m[\$c]|=16,!(\@a=grep!(\$m[\$c+\$\$_[0]]&16+\$|*\$\$_[1]),\n [- 1,8] +,[1,1],[\$w,4],[-\$w,2])?\$c=pop\@p:\${(\$i,\$j)=\@{\$a[rand\@a]}; \$m[\$c]&=~\n 8/\$j; push\@p,\$c; \$m[\$c+=\$i]&=~\$j; ++\$u-\$h*\$w+\$h||map\$_&=15,\@m,splice(\@p),\$c\n =\$|=1}until\$|&\$ +c+2>\$w*\$h; \$C=\$q-4*int\$q/4; \$A=(\$q+\$C)*\$r; \$u=pack"x"x((\$q+\$\n C)*\$r); subZd{my(\$f,\$g,\$h,\$i,\$e)=\@_; \@a=sort{"000\$a"<=>"000\$b"}\$h,\$i||\$h; f\n or(\$a[0]..\$a[1]){\$s=(\$r-\$_)*(\$q+\$C)+\$f; vec(\$u,\$_,8)=\$e||2for\$s..\$s+\$g-1}\n }; subZt{\$a=shift; \$x=10*(\$a%\$w); \$y=10*(2+int\$a/\$w)}; dZ9,\$q-20,10; dZ9,\$q-2\n 0,\$r-10; dZ9,1,10,\$r-10; dZ\$q-11,1,10,\$r-10; map{t\$_; if(\$_%\$w){\$m[\$_]&2?d\$x\n -1,11,\$y:""; \$m[\$_]&8?d\$x+9,1,\$y-10,\$y:""; }}0..-1+\$w*\$h; \$F="LIST"; open(FH\n ,">al.avi"); binmodeZFH; selectZFH; printZpack"L*",/\\d/?\$_:unpack"L*",\$_Zfo\n r"RIFF",(1256+(\$A+24)*(\ +$B=3+scalar\@p)),"AVIZ\$F",1216,"hdrlavih",56,50000\n 0,32,0,2064,\$B +,0,1,\$A,\$q,\$r,(0)x4,\$F,1140,"strlstrh",56,"vids",(0)x4,1,1\n 0,0, +\$B,\$A,-1,(0)x3,"strf",1064,40,\$q,\$r,pack("SS",1,8),0,\$A,(0)x4,pa +ck((\n "H"x1024),"f","f","f",0,"a"),\$F,(4+(\$A+8)*\$B),"movi"; map{printZSTDOUTZ++\n \$G,\$/; t\$z||1; \$l=\$x; \$t=\$y; t\$_; \$ri=\$x; if(\$l>\$x){\$ri=\$l; \$l=\$x}d\$l+2,5+\$ri-\$\n l,(\$t<\$y?\$t:\$y)-7,(\$t<\$y?\$y:\$t)-3,1 +; \$z=\$_; print"00db".pack("L",\$A).\$u}\@p\n ,(-1+\$w*\$h)x3; print"idx1".pack"L",16*\$B; \$o=4; for(1..\$B){print"00db".pack\n "LLL",16,\$o,\$A; \$o+=\$A+8}]; s[((?{$a.=$+})\s?(\S*)\s?)*][$a =~ s/Z/ /g; $a; ]see;
I knew you were writing to an .avi file (I didn't know you could do that ... very slick!), so I found the open statement:  open(FH\n ,">al.avi");.  But on the very next 2 lines:  binmodeZFH; and selectZFH;.  So you clearly had to be doing some processing on the string before using it.

Ah yes, there it is; near the end of the program is the regular expression substitution (with a double evaluation):

s[((?{$a.=$+})\s?(\S*)\s?)*][$a =~ s/Z/ /g; $a; ]see;
So the next step is to drop one of the evaluations, and print the string *before* it would have been executed.  This can even be done on the original program with some Unix pipes, and two calls to sed.  (One call converts the double-evaluation to a single evaluation, and prints the string representing the innermost program instead of executing it.  The second call simply changes semicolons to newlines to make the program readable):
% perl -MO=Deparse movies | sed s/see/se\;print/ | perl | sed s/\;/\;\ +\n/g ($w,$h)=split/x/,shift||"19x20"; $q=10+10*$w; $r=20+10*$h; @m=((31,(15)x($w-1))x$h,(31)x$w); $m[$c]|=16,!(@a=grep!($m[$c+$$_[0]]&16+$|*$$_[1]),[-1,8],[1,1],[$w,4], +[-$w,2])?$c=pop@p:${($i,$j)=@{$a[rand@a]}; $m[$c]&=~8/$j; push@p,$c; $m[$c+=$i]&=~$j; ++$u-$h*$w+$h||map$_&=15,@m,splice(@p),$c=$|=1}until$|&$c+2>$w*$h; $C=$q-4*int$q/4; $A=($q+$C)*$r; $u=pack"x"x(($q+$C)*$r); sub d{my($f,$g,$h,$i,$e)=@_; @a=sort{"000$a"<=>"000$b"}$h,$i||$h; for($a[0]..$a[1]){$s=($r-$_)*($q+$C)+$f; vec($u,$_,8)=$e||2for$s..$s+$g-1}}; sub t{$a=shift; $x=10*($a%$w); $y=10*(2+int$a/$w)}; d 9,$q-20,10; d 9,$q-20,$r-10; d 9,1,10,$r-10; d $q-11,1,10,$r-10; map{t$_; if($_%$w){$m[$_]&2?d$x-1,11,$y:""; $m[$_]&8?d$x+9,1,$y-10,$y:""; }}0..-1+$w*$h; $F="LIST"; open(FH,">al.avi"); binmode FH; select FH; print pack"L*",/\d/?$_:unpack"L*",$_ for"RIFF",(1256+($A+24)*($B=3+sca +lar@p)),"AVI $F",1216,"hdrlavih",56,500000,32,0,2064,$B,0,1,$A,$q,$r, +(0)x4,$F,1140,"strlstrh",56,"vids",(0)x4,1,10,0,$B,$A,-1,(0)x3,"strf" +,1064,40,$q,$r,pack("SS",1,8),0,$A,(0)x4,pack(("H"x1024),"f","f","f", +0,"a"),$F,(4+($A+8)*$B),"movi"; map{print STDOUT ++$G,$/; t$z||1; $l=$x; $t=$y; t$_; $ri=$x; if($l>$x){$ri=$l; $l=$x}d$l+2,5+$ri-$l,($t<$y?$t:$y)-7,($t<$y?$y:$t)-3,1; $z=$_; print"00db".pack("L",$A).$u}@p,(-1+$w*$h)x3; print"idx1".pack"L",16*$B; $o=4; for(1..$B){print"00db".pack"LLL",16,$o,$A; $o+=$A+8}
at which point the functionality of the program becomes decipherable.

I'm particularly impressed with the way you write directly to the .avi file.  I'm going to definitely study how to do that, so I can make use of it in my own code!


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