Wrap: Standalone executables with Tcl/Tk8.2.1
	references since December 16, 2000

Did you ever wondered why Tcl/Tk standalone executables need to be so big? When you use tcl2c, Freewrap or Mktclapp, generally the resulting executables are larger than 1 MByte. Here is the proof that they can be made much smaller: The Wrap 0.3 binary distribution contains two fully functionally standalone executables with the Memchan and Metakit extensions and everything to create your own standalone executables. Still everything together fits on a single floppy:

• tclsh82s.exe (406588 bytes)
• wish82s.exe (816044 bytes)
• zip.exe (62976 bytes)
• wrap0.3.tar.gz (854312 bytes, source distribution)

The Wrap binary distribution has the following features:

• Contains Memchan 2.1 (Andreas Kupries), Mk4tcl 1.1 (Jean-Claude Wippler) and TkCon (Jeffrey Hobbs)
• Contains plus-, dash-, and Img-patch.
• Standalone executables are much smaller than with other methods (tcl2c, Freewrap, Mktclapp), typically 50% or less.
• Wrap standalone executable start up much faster, a side effect of the executables being much smaller: It just takes up less time to load everything in memory.
• Wrapped scripts are only loaded in memory when used. This not only contributes favorately to the startup-time, it also benefits the memory-usage.
• Standalone executables don't need any specially dll's to be installed: They just work on Windows 95/98/NT/2000 without the need for any installation.
• You can wrap up any file type inside the executable: Not only scripts but as well GIF-files and even dll's and other executables.
• All you need as extra tool is the standard zip utility.
• Every part of the executable is compressed. The executable code is compressed with upx and all other parts are compressed with zip.
• Windows binaries are all compiled with gcc-2.95 (mingw variant) and compressed with upx.
• You can create your own standalone executables without ever running Windows: The zip utility is available on UNIX as well. If you want to try the demo below on UNIX, use use "cp" in stead of "copy", everything else works the same.

How to create your own standalone executables

The trick is that the standalone executables in reality are zip-files as well. Thus they can be handled with the standard zip-utility.. The supplied "zip.exe" in reality is nothing more than zip 2.2 ported to Windows (using gcc-2.95, mingw variant). The most important part of Wrap is the handling of zip-entries; being able to uncompress them and handle them on-the-fly in various ways.

Now - as a demonstration - let's create our first standalone executable. Assume we have a "hello.tcl" script, which we want to wrap up in an executable

  # hello.tcl
  button .b -text button -command exit
  pack .b

The procedure to do this from the DOS command line is:

  > copy wish82s.exe hello.exe
  > zip -9 -A hello.exe hello.tcl

That's all. The "-9" option (recommended) selects maximum compression and the "-A" option (obligatory) corrects for the non-standard zip-header. Now assume you want to add a GIF-file to the button, which should be wrapped in the executable as well:

  # hello.tcl
  set f [wrap::open hello.gif]
  fconfigure $f -translation binary
  set hello [read $f]; close $f
  [image create photo hello] put $hello
  button .b -image hello -command exit
  pack .b

You can wrap both the script and the GIF-file in the executable by:

  > copy wish82s.exe hello.exe
  > zip -9 -A hello.exe hello.tcl hello.gif

See how simple it really is: If you want to read data from the executable, just use wrap::open in stead of open and off you go. In the same way Wrap provides the wrap::source and wrap::load commands, which you can use according to your own fantasy.

ToDo:

• wrap::file command.
• wrap::glob command.
• Code signing (MD5).
• Many things. Idea's still have to be worked out.

Acknowledgement.

Jean-Claude Wippler

This package is for a great deal inspired by the useful discussions I had with him about software installation issues. Let's hope this partial implementation gives inspiration for more ideas.

Matt Newman

Gave many very useful suggestions, supplied the initial VC++ makefiles and the date/time handling.

Jan Nijtmans
CMG (Computer Management Group) Arnhem B.V.

email:

j.nijtmans@chello.nl (private)

jan.nijtmans@cmg.nl (work)

url:

http://purl.oclc.org/net/nijtmans/