Re: [PATCH] Really do nothing in while loop

From: Michael Tokarev <mjt@tls.msk.ru>
Date: May 8, 2005, 11:40 UTC
Message-ID: <427DFAB8.5050000@tls.msk.ru>
In-Reply-To: <12e801c553c1$c454ea20$1225a8c0@kittycat>

jdow wrote:

> From: "James Purser" <purserj@ksit.dynalias.com>
>

   while (deflate(&stream, 0) == Z_OK)
-  /* nothing */
+  /* nothing */;
  stream.next_in = buf;

Show 17 quoted lines

> 
> You guys REALLY do not see the changed semantics here? You are
> changing:
>   while (deflate(&stream, 0) == Z_OK)
>       stream.next_in = buf;
> 
> into
> 
>   while (deflate(&stream, 0) == Z_OK)
>     ;
>   /* Then the data itself.. */
>   stream.next_in = buf;
> 
> I suspect the results of that tiny bit of code would be slightly
> different, especially if "stream.next_in" is volatile, "buf"
> is volatile, or if the assignment to next_in has an effect on
> the "deflate" operation.

As I already said, deflate() in this case does only ONE iteration. stream.avail_in is NOT changed in the loop (except of the deflate() itself, where it will be set to 0 - provided out buffer have enouth room). So the whole while loop does only ONE iteration, returning Z_NEED_DATA or something the next one. So no, the semantics here (actual semantics) does NOT change.

/mjt

Re: [PATCH] Really *do* nothing in while loop

Re: [PATCH] Really do nothing in while loop