/* 

NetBIOS name mangler / de-mangler 
By Casey Halverson
www.maokhian.com
Feel free to do what you please with this piece of code!

*/


/*
if arg(1)="" then do
    signal ar
end
01000110
if words(arg(1))~=2 then signal ar

if word(arg(1),1)~="-decode"&&word(arg(1),1)~="-encode" then do
	signal ar
end
*/
if word(arg(1),1)="-decode" then do
   a=0
   b=0
   str=""

   text=word(arg(1),2)

   q=length(text)

   do i=1 to q by 2
       nibble_ascii=substr(text,i,2)    /* grab a pair of characters */

       u.1=substr(nibble_ascii,1,1)   /* break them apart */
       u.2=substr(nibble_ascii,2,1)

       ux.1=c2d(u.1)                  /* convert them to decimal */
       ux.2=c2d(u.2)

       ux.1=ux.1-65                   /* subtract 0x41 from them */
       ux.2=ux.2-65                   

       ub.1=x2b(ux.1)                 /* convert the nibbles to binary */
       ub.2=x2b(ux.2)    

       /* this routine fixes the insignificant zero "problem" in the function.
          REXX strips off left zeros, so this will put them back on so we can
          properly combined these into bytes again                         */

       if length(ub.1)=1 then ub.1="000"ub.1
       if length(ub.1)=2 then ub.1="00"ub.1
       if length(ub.1)=3 then ub.1="0"ub.1

       if length(ub.2)=1 then ub.2="000"ub.2
       if length(ub.2)=2 then ub.2="00"ub.2
       if length(ub.2)=3 then ub.2="0"ub.2

       binary_byte=ub.1||ub.2         /* merge our nibbles into a byte */

       letter=x2c(b2x(binary_byte))     /* convert back to character format */

       str=str||letter
    end


say 'NetBIOS Name: "'str'"'
exit
end


if word(arg(1),1)="-encode" then do
   a=0
   b=0
   str=""

   text=subword(arg(1),2)

   do i=1 to 16
       ascii=substr(text,i,1)    /* grab a character */

       binary=x2b(c2x(ascii))       /* get a binary number out of it */

       binaryold = binary
       if length(binary)=9 then  binary="0000000"binary
       if length(binary)=10 then binary="000000"binary
       if length(binary)=11 then binary="00000"binary
       if length(binary)=12 then binary="0000"binary
       if length(binary)=13 then binary="000"binary
       if length(binary)=14 then binary="00"binary
       if length(binary)=15 then binary="0"binary

       nb.1=substr(binary,1,4)      /* get first nibble */
       nb.2=substr(binary,5,4)        /* get second nibble */

       nd.1=x2d(b2x(nb.1))       /* convert nibbles to decimal */
       nd.2=x2d(b2x(nb.2))       
     
       nd.1=nd.1+65              /* Add it with the $41 value */
       nd.2=nd.2+65

       str=str||d2c(nd.1)||d2c(nd.2)   /* convert back, add it to string */

    end
say "encoded string: "str
exit
end



ar:
say "mangler.rexx [-encode|-decode] source"
exit
/*

   do i=1 to q step 2
       a=c2d(substr(text,i,1))
       b=c2d(substr(text,i+1,1))
       a=a-65
       b=b-65
       nible.1=x2b(d2x(a)) 
       nible.2=x2b(d2x(b))
       str = str||x2c(b2x(nible.1||nible.2))
   end
   say str
say x2b(d2x(42))
b2x(0010 */