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From "Bill Stoddard" <>
Subject Re: Mod_include design
Date Thu, 02 Nov 2000 20:49:27 GMT

> On Thu, Nov 02, 2000 at 12:44:15PM -0800, wrote:
> >...
> > Greg's comment that we might as well copy as we find the tag, I don't
> > agree with either.  Picture a brigade that looks like:
> >
> > "<" -> "!" -> "-" -> "foobar"
> >
> > This is an invalid tag.  If we copy as we find things, then we will copy
> > things into the buffer that isn't really a tag, and if we use the presence
> > of data in the buffer to siginify a tag, then we have a problem.
> >
> > If we copy the tag once we have found the full tag, then we can actually
> > allocate a buffer of the correct size for the tag that we have.
> You are going to do one of two things as you look for the tag:
> 1) set aside a brigade
> 2) copy into a buffer
> Given that (1) might do a copy, and that you will eventually do (2), then
> you may as well do it as you go.
> And, oh, gee, heavens-to-betsy, we find that the tag is invalid. Well, gosh
> darnit. We went and copied four bytes into a buffer and now we need to send
> that all down to the next filter.
> Yah, right. Like we need to be worried about those four bytes.
> Copy the darn thing until you find your tag. It keeps it clean and simple,
> and there is next to zero performance degradation. I don't understand the
> rationale for a bunch of complexity to avoid copying four bytes

Yes, I agree with Greg here. If you see what you think is a tag, assume it IS
a tag and copy it. If you later discover it is not really a tag, then send it
out on the wire. The performance impact is minimal and it is certainly not
worth adding even more complexity to the code to handle this case more



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