[MERGE] rand_chars() optimization

[Dmitry Vasiliev]

Marius Gedminas wrote:
> On Sun, Mar 11, 2007 at 03:43:59PM +0300, Dmitry Vasiliev wrote:
>> +
>> +class RandCharsBenchmark(Benchmark):
>> +
>> +    def test_rand_chars(self):
>> +        def generate_rand_chars():
>> +            items = set(osutils.rand_chars(50) for i in xrange(200000))
> 
> Why do you include the creation of a large set of strings in the
> benchmark?

Good catch, actually it just was a copy/paste from the corresponding 
test. I'll change it into less memory-aggressive code like this:

     for i in xrange(200000):
         item = osutils.rand_chars(50)

>>  ALNUM = '0123456789abcdefghijklmnopqrstuvwxyz'
>> +_rand_chars_map = dict((chr(i), ALNUM[i % 36]) for i in range(256))
> 
> I suspect it might be a bit faster if you used a string rather than a
> dict here:
> 
>   _rand_chars_map = ALNUM * (255 / len(ALNUM) + 1)

But how it may helps to make rand_chars() any faster? With 
_rand_chars_map as a dict you just can do later _rand_chars_map[raw_byte].

-- 
Dmitry Vasiliev <dima at hlabs.spb.ru>
http://hlabs.spb.ru