* Beef-up testing of str.__contains__() and str.find().
* Speed-up "x in y" where x has more than one character.
The existing code made excessive calls to the expensive memcmp() function.
The new code uses memchr() to rapidly find a start point for memcmp().
In addition to knowing that the first character is a match, the new code
also checks that the last character is a match. This significantly reduces
the incidence of false starts (saving memcmp() calls and making quadratic
behavior less likely).
Improves the timings on:
python -m timeit -r7 -s"x='a'*1000" "'ab' in x"
python -m timeit -r7 -s"x='a'*1000" "'bc' in x"
Once this code has proven itself, then string_find_internal() should refer
to it rather than running its own version. Also, something similar may
apply to unicode objects.
2 files changed