My attempts to speed up the core of Behold led me to lean towards using the DISQLite3 database package. The expectation was that it would perform better than the b-tree structure I developed in prehistoric times for handling the internal data. But I may have discovered something even better.
XML (Extensible Markup Language) is a new technology developed to transport and store data. It contains start <TAGS> that are closed by ending </TAGS>. Between the start and end tags is the value associated with the tag. Tags can be nested.
Hmmm. GEDCOM looks like this:
0 @I32@ INDI
1 NAME John /Smith/
2 DATE 04 MAY 1824
2 PLAC Paris, France
It has tags, values, and numbers indicating a level of nesting.
But here’s some XML:
<DATE>04 MAY 1824</DATE>
The XML is exactly the same thing, as the GEDCOM.
New versions of Delphi have built-in support of XML, including support of the DOM (Document Object Model) that defines a standard way for accessing and manipulating XML documents.
What this means for Behold is that I can get it to read in the GEDCOM as XML and store it internally in memory that way for easy access while Behold is running. That will allow me to “virtualize” the ElTree treeview to use that data, and possibly also virtualize RichView to use that data (although I’m not sure if the last one is feasible yet).
Then it will be an easy matter to save the XML back to GEDCOM again. This is a great way to implement saving of GEDCOMs. It will be easy enough to do that it will now be added into the next release, rather than having to wait until Version 1.5 as I had earlier planned.
Will XML be as fast as a database, or even as fast as my current b-tree data structure? I don’t know, but when looking around for a XML implementations that may be faster than Delphi’s, I was surprised to find that LMD has an XML library, and surprise of surprises, it’s included with the LMD ElPack package that I just upgraded to.
So this is the next step, and I’ll start to implement it after a good night’s sleep.