Efficient string matching algorithm

Question

I\'m trying to build an efficient string matching algorithm. This will execute in a high-volume environment, so performance is critical.

Here are my requirements:

Answer 1

If it was just matching strings, then you should look at trie datastructures and algorithms. An earlier answer suggests that, if all your wildcards are a single wildcard at the beginning, there are some specific algorithms you can use. However, a requirement to handle general wildcards means that, for fast execution, you're going to need to generate a state machine.

That's what a regex library does for you: "precompiling" the regex == generating the state machine; this allows the actual match at runtime to be fast. You're unlikely to get significantly better performance than that without extraordinary optimization efforts.

If you want to roll your own, I can say that writing your own state machine generator specifically for multiple wildcards should be educational. In that case, you'll need to read up on the kind of algorithms they use in regex libraries...