From: Gary Wright <gwtmp01@...>
Date: 2010-01-17T04:18:04+09:00
Subject: Re: How can I modify the xml file directly?


On Jan 16, 2010, at 12:50 PM, Seebs wrote:

> On 2010-01-16, Milo Luo <lxybhbh@gmail.com> wrote:
>> I meant without string or tmp file, write to original file.
> 
> In general, on most systems, the only modifications you can make without
> a temporary file or something comparable are those which do not change the
> number of characters in a file.  You can't insert or delete characters in
> the middle of a file.

I often wondered if there is any OS floating around out there that goes
beyond the traditional file semantics (replace, append, truncate, extend).
For example:
  -- prepend
  -- delete (from beginning or middle)
  -- insert

I would think that many of those operations would be painfully inefficient
unless perhaps they were done on block-sized chunks to avoid having to
keep track of partially used blocks.

Gary Wright