[icu-support] Partial regex match

[Richard G. <rg...@us...>]

Dear icu-support--

I have a task I'd like to be able to use the ICU regex facility to perform,
but I'm not sure if it's possible or how to go about it, and was hoping
some of the ICU experts here could give me some advice.

I have a large list of strings-- over 10 million, generally shorter than 15
characters or so-- and I want to find all the strings in that list that
match a given regular expression.  I could do this by passing each of them,
one at a time, to a RegexMatcher, but this is likely to be extremely slow.

The list is stored as a trie.  What I'm after is some way of telling not
just whether a given string matches a regex, but whether there are any
strings that *begin with* a given string that match the regex.  For
example, in addition to "Does 'bl' match this regex?" I need to be able to
ask "Does any string beginning with 'bl' match this regex?"  I'm not seeing
anything in the API docs that sounds like it'll do this.  If I'm right
about this, is there a way I could go about cannibalizing the current ICU
code to implement this, maybe with an eye toward including it in a future
version of ICU?

Thanks for whatever help you can give...

--Rich Gillam
  IBM