Provides any amount of requested memory (as long
as there is available RAM) and associates that
memory with a user-defined alphanumeric key.
Features very fast retrieval in sorted order, even
faster sequential access (in the chronological
order the requests were made).
The alphanumeric keys are associated with a
certain quantity of bytes located at a designated
position in RAM. That RAM is and remains
exclusively reserved for that Key. Via the key the
address can be returned, and also the reserved
bytes at that address. Keys are internally managed
with a balanced binary AVL tree. It is possible to
iterate through the whole collection of keys in
the order in which these keys were created (and
the memory allocated), returning the Key, the
Memory Address and the Size. It is also possible
to access all the Keys in sorted order (ascending
as well as descending). All operations are
considerabily faster than VB's Collection object
(as far as such functions are provided by the
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With 2 million elements, my VB 6 SP 5 under Win 2000 Pro says "Out of memory" (having 1.3 GB :p) - well, the DLL can handle 5 million entries easily (that's as far as I went when testing, although the key generation process becomes a nuysance then, due to repetitions in the Rnd() sequences: use a prime number as key length if you're going to try the same). However, it's just so that VB won't let me create a larger string array to store the generated keys in the test form's array.
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True, enmity: As is the case with all VB projects, it is much faster when compiled. When running the project in the IDE, the built-in (already "compiled") Collection object wins by lengths.
The reference to SatBNF refers to another DLL (Backus Naur Form lexer and parser, which I might upload as well in a few days after some more testing, possibly also within a tutorial describing parser building in VB). It merely escaped my attention to remove that reference from the file "SatStructures.vbp". For now, you can safely delete the line "Class=SatBNF;" in there. (If this comment was disrespectful, please report it.)
First I would like to thank you for your superb AVL class. It is very much appreciated.
VB's Collection object has a reputation for being surprisingly fast for insertion and key lookups so blowing it away with this AVL tree is impresssive.
I'm lead to believe the VB Collection object uses a hash table or a binary tree internally for its fast performance.
I selected your AVL class as my basis for a fast VB Collection substitute.
However, after creating a node removal algo I needed to test it. I set up to test the trees validity before and after a node delete operation - and it failed before!
A couple of slight changes to your double rotation routines fixed the subtle bugs that maintained a valid binary search tree but not a valid AVL balance on certain situations. The second (or third) last line in each routine was the culprit if I remember correctly. ... cont'd next comment ... (If this comment was disrespectful, please report it.)
super, :) (If this comment was disrespectful, please report it.)
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