dynamic allocation file buffer

Steven D'Aprano steven at REMOVE.THIS.cybersource.com.au
Fri Sep 12 08:30:42 CEST 2008


On Thu, 11 Sep 2008 22:40:01 -0700, Dennis Lee Bieber wrote:

> On 12 Sep 2008 03:37:51 GMT, Steven D'Aprano
> <steven at REMOVE.THIS.cybersource.com.au> declaimed the following in
> comp.lang.python:
> 
> 
>> I'm pretty sure you're wrong. XML can be used for serialization, but
>> that doesn't mean it is only sequential data. XML is suitable for
>> hierarchical data too. To quote Wikipedia:
>>
> 	There is a difference between the format of the data content, and
> the processing of that data... Regardless of the content, one
> essentially has to process the XML /file/ sequentially, and translate
> into an in-memory model that allows for accessing said data. To reach
> the nth subelement of the mth element requires reading all 1..m-1
> elements, followed by all 1..n-1 subelements in m. Modifying any element
> requires rewriting the entire file.

Which is why I previously said that XML was not well suited for random 
access.

I think we're starting to be sucked into a vortex of obtuse and opaque 
communication. We agree that XML can store hierarchical data, and that it 
has to be read and written sequentially, and that whatever the merits of 
castironpi's software, his original use-case of random access to a 4GB 
XML file isn't workable. Yes?



-- 
Steven



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