Re: binary test and position?

[ToddAndMargo via perl6-users]

On 2/2/19 6:09 AM, Brad Gilbert wrote:
     sub buf-index ( Buf $buf, +@match ) {
         my $elems = @match.elems;
         $buf.rotor( $elems => 1 - $elems ).first(* eqv @match.List, :k)
     }
     my $buf = Buf[uint8].new(0x4D, 0x5A, 0x90, 0x00, 0x03);

     say buf-index( $buf, (0x90, 0x00, 0x03)); # 2

What did I do wrong?

First I did a byte wise conversion of

   Buf $BinaryFile   to   Str $StrFile

and

   Buf $VersionInfoBuf  to  Str $VersionInfoStr



sub Buf-Index ( Buf $Buffer, +@SubBuf ) {
   # `index` for buffers
   # $Buffer is the buffer to search through
   # $ +@SubBuf is the sub buffer pattern to search for in $Buffer
   # returns the first instance of a match, Nil if no match

   my Int $Position = Nil;
   my $Elems = @SubBuf.elems;

   $Position = $Buffer.rotor( $Elems => 1 - $Elems ).first( * eqv 
@SubBuf.List, :k );
   return $Position;
}

   $i  = index(     $StrFile,    $VersionInfoStr );
   $bi = Buf-Index( $BinaryFile, $VersionInfoBuf );
   say "i = <$i>   bi = <$bi>";




$ FileVer.pl6
i = <11371>   bi = <>


11371 is correct.



What did I do wrong?

Many thanks,
-T