Re: [PATCH 13/10] tests for various pack index features

Olivier Galibert [off-list ref] wrote:

On Wed, Apr 11, 2007 at 08:57:09AM -0400, Nicolas Pitre wrote:

quoted

Hmmm what we need is a random data generator that always produces the 
same thing.  I'll hack something to replace urandom.

Don't hack something, ues the standard reference, the Mersenne Twister.

  http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html

PRNGs are the same as cryptosystems, it's very easy to hack up
something and get it very, very wrong.  And it's unnecessary, since
there are very good ones available.

Indeed.  But Mersenne Twister doesn't have code to produce a random
file of size X given an initial constant seed of Y, does it?
A small program to produce X random bytes starting with seed Y
still needs to be hacked up.

Probably the smart thing to do here is to embed a copy of MT with
constant seeds so we always get the same data file produced on
every system, no matter what the implementation of the C library's
rand routine is.

Although MT is not GPL. It has its own license, one with a small
advertising clause...

-- 
Shawn.