compression filters

From: Herve Bronnimann (hbr_at_[hidden])
Date: 2000-10-19 14:09:22

Hi everyone:

Just a (few related) questions:

1. what would be the relevance of a few generic compression filters to boost?

I'd like to know, because in my class I asked my students to program
runlength_{en|de}code, mtf_{en|de}code (move to front), bwt_transform
(Burrows/Wheeler, used in bzip2 among others), huffman_{en|de}code (we
haven't done the canonical codes), and we tried to present them
generically. You can look at the interfaces in
  http://photon.poly.edu/~hbr/cs903/doc/mtf_decode.html
  http://photon.poly.edu/~hbr/cs903/doc/mtf_encode.html
  http://photon.poly.edu/~hbr/cs903/doc/runlength_encode.html
  http://photon.poly.edu/~hbr/cs903/doc/runlength_decode.html
  http://photon.poly.edu/~hbr/cs903/doc/burrows_wheeler.html
  http://photon.poly.edu/~hbr/cs903/doc/inverse_burrows_wheeler.html
  http://photon.poly.edu/~hbr/cs903/doc/huffman_code.html
  http://photon.poly.edu/~hbr/cs903/doc/huffman_encode.html
  http://photon.poly.edu/~hbr/cs903/doc/huffman_decode.html
They need a lot of work, comments are welcome (perhaps private email, 
not on this list yet).

As a project I could ask a student to boostify it, as a starting point...
I'm just looking for comments at this point. I realize it might be too
specific or application oriented. Also, it might be too ambitious :)

2. Another related question that came up in burrows_wheeler, is:
has anobody designed a generic counting_sort? block_sort? What would
generic interfaces for those extensions be?

3. One problem that came up, by the way, was to associate a positive index
to a character type. I'll post it in another thread. There might be a
simple boost solution,

Regards,
-- 
Hervé