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From: Jonathan Nieder <jrnieder@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jeff King <peff@peff.net>, Derrick Stolee <stolee@gmail.com>,
	git@vger.kernel.org
Subject: Re: [PATCH] xrealloc: do not reuse pointer freed by zero-length realloc()
Date: Wed, 2 Sep 2020 20:50:08 -0700	[thread overview]
Message-ID: <20200903035008.GF4035286@google.com> (raw)
In-Reply-To: <xmqq3641ebep.fsf@gitster.c.googlers.com>

Junio C Hamano wrote:
> Jeff King <peff@peff.net> writes:

>> If we do handle it up-front, then I think we'd actually want:
>>
>>   if (!size) {
>>           free(ptr);
>>           return xmalloc(0);
>>   }
>>
>> (i.e., to never return NULL for consistency with xmalloc() and
>> xcalloc()).
>
> Makes sense.  I suspect that this is optimizing for a wrong case,
> but in practice that should not matter.  Not having to worry about
> a request to resize to 0-byte in the remainder of the function is
> actually a plus for readability, I would say.

I agree with both points: if we were repeatedly shrinking and growing
a buffer and cared about its performance, then we'd want the first
version, and since we aren't, we should prefer this version that is
more readable.

Thanks,
Jonathan

  parent reply	other threads:[~2020-09-03  3:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 11:18 Jeff King
2020-09-01 13:04 ` Derrick Stolee
2020-09-01 13:51   ` Jeff King
2020-09-01 14:24     ` Derrick Stolee
2020-09-01 15:58     ` Junio C Hamano
2020-09-02  7:54       ` Jeff King
2020-09-02 19:19         ` Junio C Hamano
2020-09-03  3:50       ` Jonathan Nieder [this message]
2020-09-01 15:20 ` Andreas Schwab
2020-09-01 15:56 ` Junio C Hamano

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