Hello again
I have setup small page where I am publishing all the profiling and
evaluation results. It is here: http://83.168.205.202/~michal/
standard15/
So far I have put there function usage profile, zend_memnstr
analysis, stripos and strrpos analysis including some charts etc. CVS
diffs where applicable are also posted along with comparison of
original and patched code.
Michal
On 2008-06-11, at 09:47, Stanislav Malyshev wrote:
Hi!
Here are some statistics:
- average haystack length: 624.2
- average needle length: 1.9 ! -> 63% of needles of length 1
- avg length of haystacks shorter than avg: 41.0 -> 85% of all
haystacks
- avg length of haystacks longer than avg: 5685.11
I think it would be interesting to see same excluding 1-char
needles since in this case it should do one-char lookup (btw, if we
don't do it on C level, it might be a good idea to).
Although strpos implements fix for that, some other functions
don't. My idea
is than to implement ZEND_MEMNSTR once again in shape:
if (needle_len = 1)
here just linear sweep
else if haystack_len < 5000 (5000 is arbitrary - maybe some more
tests
needed to choose good value)
original implementation (as it is the best one in this case)
else
BM/KMP (i think BM will be better in this case, as some people
suggested)
I'm not sure very big haystacks really worth the trouble - how many
of them are used? It may be interesting to see medians instead of
averages for that. But len=1 I think worth having special case.
--
Stanislav Malyshev, Zend Software Architect
[EMAIL PROTECTED] http://www.zend.com/
(408)253-8829 MSN: [EMAIL PROTECTED]
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