[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML Memory Requirements (was Re: Feeling good about SML)
At 05:55 PM 11/17/99 -0500, David Megginson wrote: >Again, the big problem in creating a tiny XML processor is the >required error reporting for illegal characters in names, attribute >values, etc. -- if you build lookup tables, you're looking at an >enormous amount of memory for each table. Actually, it's not so bad as all that. The trick is this: there are only a few interesting states, of which you're in one of these 3 most of the time: - processing character data - processing a name (e.g. element type or attribute name) - processing the first character of a name For the first, can check the small number of excluded regions with an if statement. For the others, you have a (relatively) small array of pairs of numbers being the low-high edges of legal ranges, then you binary-search them. In Lark, the class that does all the work is only 3.5K (the arrays are compressed in the class file, so maybe 10* times in memory). The performance is good enough that in Lark, the limiting factor was my lousy input buffering, not the character class checking; and Lark was always in the top half of the performance table. -Tim xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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