faster splitter

[Andrei Alexandrescu via Digitalmars-d]

On 5/27/16 8:28 AM, Chris wrote:
> I've played around with some algorithms and kept them as simple as
> possible, but I've found that a linear brute force for-loop always beats
> them (it's the extra decision(s), I suppose). It looks nice in theory,
> but in hardware reality a stupid loop is more efficient.

This is surprising. It should be easy to construct examples where brute 
force search performs arbitrarily poor, e.g. searching for 
"aaaaaaa...aab" in a long string with only "a"s.

> NB: I've found that `foreach` is usually faster than a manual `for`-loop.

That's surprising too. I'd be interested to look at a disassembly if you 
have one.

> I used qznc's benchmarking, and it's clear that the current
> implementation of std.algorithm.find is quite a poor performer. We do
> have to work on that. Library functions should be fast, no matter what.
> If someone uses `find`, they wanna be sure it's optimized for speed.

That's definitely the way to go. Thanks for looking into it!


Andrei