Am Mo., 13. Apr. 2020 um 00:20 Uhr schrieb James Almer <jamr...@gmail.com>:
>
> On 4/12/2020 7:07 PM, Carl Eugen Hoyos wrote:
> > Am So., 12. Apr. 2020 um 23:58 Uhr schrieb James Almer <jamr...@gmail.com>:
> >>
> >> On 4/12/2020 6:53 PM, Carl Eugen Hoyos wrote:
> >>> Am So., 12. Apr. 2020 um 23:52 Uhr schrieb James Almer
> >>> <jamr...@gmail.com>:
> >>>>
> >>>> On 4/12/2020 5:55 PM, Carl Eugen Hoyos wrote:
> >>>>> Am So., 12. Apr. 2020 um 22:48 Uhr schrieb James Almer
> >>>>> <jamr...@gmail.com>:
> >>>>>>
> >>>>>> On 4/11/2020 8:53 PM, Carl Eugen Hoyos wrote:
> >>>>>>> Am So., 12. Apr. 2020 um 00:44 Uhr schrieb Carl Eugen Hoyos
> >>>>>>> <ceffm...@gmail.com>:
> >>>>>>>>
> >>>>>>>> Am So., 5. Apr. 2020 um 14:03 Uhr schrieb Michael Niedermayer
> >>>>>>>> <mich...@niedermayer.cc>:
> >>>>>>>>>
> >>>>>>>>> On Sat, Apr 04, 2020 at 12:46:36AM +0200, Carl Eugen Hoyos wrote:
> >>>>>>>>>> Hi!
> >>>>>>>>>>
> >>>>>>>>>> Attached patch makes the alloc array functions more similar to
> >>>>>>>>>> av_malloc, depending on max_alloc_size instead of INT_MAX.
> >>>>>>>>>>
> >>>>>>>>>> Allows a work-around for ticket #7140
> >>>>>>>>>>
> >>>>>>>>>> Please comment, Carl Eugen
> >>>>>>>>>
> >>>>>>>>>> mem.c | 8 ++++----
> >>>>>>>>>> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>>>>>>>>> 507531ed6f0932834d005bc1dd7d18e762f158b2
> >>>>>>>>>> 0001-lavu-mem-Make-alloc-array-functions-more-similar-to-.patch
> >>>>>>>>>> From 7ae240a9f7885130251031aba5d0764b11947fec Mon Sep 17 00:00:00
> >>>>>>>>>> 2001
> >>>>>>>>>> From: Carl Eugen Hoyos <ceffm...@gmail.com>
> >>>>>>>>>> Date: Sat, 4 Apr 2020 00:37:03 +0200
> >>>>>>>>>> Subject: [PATCH] lavu/mem: Make alloc array functions more similar
> >>>>>>>>>> to
> >>>>>>>>>> av_malloc().
> >>>>>>>>>>
> >>>>>>>>>> Do not limit the array allocation functions to allocations of
> >>>>>>>>>> INT_MAX,
> >>>>>>>>>> instead depend on max_alloc_size like av_malloc().
> >>>>>>>>>>
> >>>>>>>>>> Allows a workaround for ticket #7140.
> >>>>>>>>>> ---
> >>>>>>>>>> libavutil/mem.c | 8 ++++----
> >>>>>>>>>> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>>>>>>>>
> >>>>>>>>> av_size_mult() may be faster
> >>>>>>>>
> >>>>>>>> New patch attached.
> >>>>>>>
> >>>>>>> And an actually working variant.
> >>>>>>>
> >>>>>>> Please comment, Carl Eugen
> >>>>>>
> >>>>>>> From 643c501d6698d7d17e47a9f907165649f1446fa6 Mon Sep 17 00:00:00 2001
> >>>>>>> From: Carl Eugen Hoyos <ceffm...@gmail.com>
> >>>>>>> Date: Sun, 12 Apr 2020 00:36:30 +0200
> >>>>>>> Subject: [PATCH] lavu/mem: Make other alloc functions more similar to
> >>>>>>> av_malloc().
> >>>>>>>
> >>>>>>> Do not limit the array allocation functions and av_calloc() to
> >>>>>>> allocations
> >>>>>>> of INT_MAX, instead depend on max_alloc_size like av_malloc().
> >>>>>>>
> >>>>>>> Allows a workaround for ticket #7140.
> >>>>>>> ---
> >>>>>>> libavutil/mem.c | 20 ++++++++++++--------
> >>>>>>> 1 file changed, 12 insertions(+), 8 deletions(-)
> >>>>>>>
> >>>>>>> diff --git a/libavutil/mem.c b/libavutil/mem.c
> >>>>>>> index 88fe09b179..e044374c62 100644
> >>>>>>> --- a/libavutil/mem.c
> >>>>>>> +++ b/libavutil/mem.c
> >>>>>>> @@ -183,23 +183,26 @@ int av_reallocp(void *ptr, size_t size)
> >>>>>>>
> >>>>>>> void *av_malloc_array(size_t nmemb, size_t size)
> >>>>>>> {
> >>>>>>> - if (!size || nmemb >= INT_MAX / size)
> >>>>>>> + size_t result;
> >>>>>>> + if (av_size_mult(nmemb, size, &result) < 0)
> >>>>>>> return NULL;
> >>>>>>> - return av_malloc(nmemb * size);
> >>>>>>> + return av_malloc(result);
> >>>>>>
> >>>>>> If I'm reading this right, when size is 0, instead of NULL this will
> >>>>>> now
> >>>>>> return av_malloc(0), which looks like it may end up being a pointer to
> >>>>>> a
> >>>>>> 1 byte big buffer. Is that intended?
> >>>>>>
> >>>>>> The previous version you sent apparently considered that scenario.
> >>>>>
> >>>>> But it did not pass fate because the behaviour before the patch
> >>>>> was not to return NULL for alloc(0).
> >>>>
> >>>> Before this patch it would return NULL when size was 0 and alloc(0) when
> >>>> nmemb was 0. Now it will return alloc(0) when either of the two
> >>>> arguments is 0.
> >>>>
> >>>> The check should be (!size || av_size_mult(nmemb, size, &result) < 0) or
> >>>> similar instead, if we want to keep the original behavior.
> >>>
> >>> How did the original behaviour make any sense?
> >>
> >> Not saying it made sense, i'm saying we changed that behavior when the
> >> patch, at least based on the description, only tried to replace the
> >> INT_MAX limit with max_alloc_size.
> >>
> >> If making size 0 return malloc(0) was intended, or ultimately preferred,
> >> then I'll not oppose to it.
> >
> > To me, the old behaviour (returning NULL for some argument being 0
> > but not the other) made less sense than the new behaviour (not
> > special-casing 0 for any argument).
> > The fact that returning NULL broke fate surprised me but I failed
> > to find the reason.
>
> I'm fairly sure your first patch failed because it made one of these
> functions return NULL for an nmemb == 0 case in some test, when it was
> not expected to.
Of course.
But I failed to find the calling function.
> Also, if you look at the doxy for these functions, they mention how they
> should behave depending on if size or nmemb are 0. Most of these don't
> seem to be honoring their documentation.
There was never anything free'd, no?
Carl Eugen
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