[MACTCL] CRC32 in Tcl

[lenny b. <kee...@ya...>]

Has anyone here any experience
in using Tcl to calculate CRC32 values for files?

Is this something only done as a C extension or can Tcl do it?
How slow/fast would it be if Tcl did it instead of C?

I ask this because I'm interested in using Tcl to calculate CRC32 for files
but also because I want to avoid platform-dependence.



Here's the only non-language-specific source I could find
for the technical breakdown of how CRC32 calculation works.

      ftp://ftp.rocksoft.com/papers/crc_v3.txt

      A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS by Ross N. Williams.
      ==================================================
      "Everything you wanted to know about CRC algorithms, but were afraid
      to ask for fear that errors in your understanding might be detected."

I found several C routines for CRC32 calculation as well.
Is there some way to convert a simple C routine to a purely Tcl procedure?
Or is the writing of a pure-Tcl CRC32-calculating procedure difficult?




Apparently there are two ways to calculate the CRC32 value for a file
(by table and by math).  I'm not sure how this relates to discussion 
I've heard of a polynomial issue which causes values not to match 
lists generated by certain popular applications.  I have no idea what 
what I've just said means.


Does anybody have any ideas?


-- 

I am not a comedian, I am Lenny Bruce.              kee...@ya...
http://www.geocities.com/keeptruthfree/

_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com