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From Joe Schaefer <joe+apa...@sunstarsys.com>
Subject Re: libapreq2?
Date Sat, 05 May 2007 21:03:30 GMT
Joe Schaefer <joe+apache@sunstarsys.com> writes:

> 2) this code
>
>     if (rawQuery)
>         rawQuery  = apr_pstrcat(r->pool, rawQuery, data, NULL);
>     else
>         rawQuery = (char *)data;
>
> is dangerous for two reasons: the allocator is quadratic (O(n^2)),
> and data may be a freed pointer by the time it's used later in the
> code. One way to fix the allocation issue, I think, is to use a
> doubling algorithm (always allocate twice the current length, and
> track how much is being used), but I haven't tested it, and that's not
> what apreq actually uses. 

I've thought about this a bit more, and the technique I describe
should amount to a total allocation of not more than 4*size of input,
which is O(n) (and therefore ok).  Do we all see the problem yet,
or should I fill in more of the details?

-- 
Joe Schaefer

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