> there are lot of application where you can't use null terminated string and
> ordering of the key is necessary:
> - Intervall searching (ex. IP-range search)
> - Longest prefix matching (ex. IP6)
> - multi-field indexing (ex.combination of integer+string)
> - prefix matching
> - Longest prefix matching in binary files
> - Match finder in data compression

Sure, I got you.

> - Maybe it is hard to implement this with the current Judy arrays
> concept.  I think the Judy arrays functions (ordered, not JudyHS) can
> be extended to fixed length keys where you can pass the fixed length
> as parameter.

OK, if all keys/indexes are the same length, just not happening to be 4
or 8, you can get them saved efficiently and lexicographically sorted
using JudyL array-of-array like how JudySL works.  The real challenges
aren't with variable-length keys where all keys are the same length in
one dataset, but where they are different lengths (and not
length-terminated but instead length-associated) within the dataset.

At one time we considered JudyVL (I think it was called) for functions
where the key length was variable -- but constant for each entire
dataset.

By the way bear in mind the power of common-substring sharing (a
by-expanse tree has this feature where by-population storage does not
necessarily), and the avoidance of expensive "hashing algorithms" to
map keys to storage locations.  You can think of libJudy as a hash table
where the hashing/decoding algorithm is to peel off one byte at a time
and use it to address the next level.

And you can think of array-of-array as a tree where the expanse of each
node is 2^32 or 2^64, very wide and flat yet without being too expensive
to traverse.

Cheers,
Alan

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