randint() now supports ranges greater than 65535

[ekimekim]

Previous behaviour caused program to hang. New upper limit on range is essentially arbitrary.

It does this by, instead of retrieving a uint16, it retrieves a number of uint16s and uses a bit shift to construct a larger-bit random number. It then performs the standard anti-modulo-bias algorithm on that.

[lmacken]

Thanks for the patch, Mike! I'll spin up a new release and push it to PyPi now.

[lmacken]

Hmm, I can't seem to get the randint unit test working with your patch. Can you give it a look when you get a chance?

[ekimekim]

Ok, so I found the problem and fixed it, but due to a series of unfortunate coincidences (mostly involving a crappy out-of-date ubuntu install that I swear i'll get around to dist-upgrading one day), I can't actually push to github at the moment. The tests now pass. I'll remember to check that next time. I can push this commit tomorrow, but if you want to fix this quickly, here's the git show of the commit:

Fix an off-by-one error when using range as a bit width.

This was causing a hang when range == 1,
and would have also resulted in a value of 65536 never being seen
in a request like randint(0,65536).

diff --git a/quantumrandom/__init__.py b/quantumrandom/__init__.py
index eab0f37..3f39663 100644
--- a/quantumrandom/__init__.py
+++ b/quantumrandom/__init__.py
@@ -85,7 +85,7 @@ def randint(min=0, max=10, generator=None):
     if generator is None:
         generator = cached_generator()

-    source_bits = int(math.ceil(math.log(range, 2)))
+    source_bits = int(math.ceil(math.log(range + 1, 2)))
     source_size = int(math.ceil(source_bits / float(INT_BITS)))
     source_max = 2**(source_size * INT_BITS) - 1

[lmacken]

Awesome, thanks for tracking this down! I'll let you commit it tomorrow so you get attribution for the fix. No rush, since I didn't push a new version out yet.

Instead of dist-upgrading Ubuntu, you should just install Fedora ;) (I'm extremely biased, since I work on Fedora for a living)

[ekimekim]

Actually I'm firmly in the ArchLinux camp :P, my laptop's just old and I don't use it often. Thanks.

[lmacken]

Cool :)

If you can't manage to push your fix to github, feel free to send me a git formatted patch instead.

Cheers.