What you describe in the first paragraph quoted here is almost hashing.
Hashing involves applying a hash function that maps a string
to a (usually) unique number. That number is then truncated in some manner
to be the index into your hash table. In your case this would be the table
of commands. As Wouter already mentioned you then do a char by char check
on the hash table entry that you find (assuming one was found) to double
check that the command is indeed a proper match.

On a PC a hash table gives you very fast access to data with a trade off
in memory. Perhaps a hash table with linear probing would work well for
your application (Google should be able to return lots of computer science
course notes with info on how that works). It would be a lot more work over
basic string comparisons though.

Wesley

On Wed, Aug 13, 2003 at 07:21:10AM +0100, Trevor Page wrote:
> I know one other way could be to take the checksum of the input string
> and compare that with checksums of the strings in ROM which is a much
> faster process, but this would result in other randomly typed character
> combinations potentially causing a 'match' too, unless there is a more
> clever way of doing it.
>
> Or there is the hash process which I am vaguely familiar with, but I
> don't know if this is what I need.

--
Wesley Moore                             http://wmoore.freeshell.org/
RMIT - BEng (Comp Sys Eng)/BApp.Sc. (Comp Sci)  5th (And Final!) Year
SDF Public Access UNIX System                http://sdf.lonestar.org/

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