On Tue, Jul 02, 2019 at 08:42:43PM -0300, James Almer wrote: > On 7/2/2019 5:56 PM, Michael Niedermayer wrote: > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > --- > > doc/APIchanges | 3 +++ > > libavutil/mem.h | 13 +++++++++++++ > > libavutil/version.h | 2 +- > > 3 files changed, 17 insertions(+), 1 deletion(-) > > > > diff --git a/doc/APIchanges b/doc/APIchanges > > index b5fadc2a48..65b8ed74ad 100644 > > --- a/doc/APIchanges > > +++ b/doc/APIchanges > > @@ -15,6 +15,9 @@ libavutil: 2017-10-21 > > > > API changes, most recent first: > > > > +2019-07-XX - XXXXXXXXXX - lavu 56.31.100 - mem.h > > + Add av_memcpy() > > + > > 2019-06-21 - XXXXXXXXXX - lavu 56.30.100 - frame.h > > Add FF_DECODE_ERROR_DECODE_SLICES > > > > diff --git a/libavutil/mem.h b/libavutil/mem.h > > index 5fb1a02dd9..a35230360d 100644 > > --- a/libavutil/mem.h > > +++ b/libavutil/mem.h > > @@ -506,6 +506,19 @@ void *av_memdup(const void *p, size_t size); > > */ > > void av_memcpy_backptr(uint8_t *dst, int back, int cnt); > > > > +/** > > + * memcpy() implementation without a NULL pointer special case > > + * > > + * @param dst Destination buffer > > + * @param src Source buffer > > + * @param cnt Number of bytes to copy; must be >= 0 > > + */ > > +static inline void av_memcpy(void *dst, const void *src, size_t cnt) > > How many cases are there in the codebase where cnt can be 0, and dst or > src NULL, without it having been checked before calling memcpy? And from > those, which would not be from situations where the code should have > instead aborted and returned ENOMEM, or EINVAL if either of them are > function arguments?
There are around 2500 occurances of memcpy in the codebase To awnser your question it would be needed to review all of them and in many cases their surrounding code. So that is unlikely to be awnsered by anyone accuratly Also iam not sure i understand why you ask or why this would matter the suggested function allows to simplify cases where the NULL can occur, not where it cannot or should not. That is this is intended for the cases where we already have or are adding explicit checks to avoid the NULL case. i could rename this to av_memcpy_nullsafe which would make it clearer but also its more to write and read thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Modern terrorism, a quick summary: Need oil, start war with country that has oil, kill hundread thousand in war. Let country fall into chaos, be surprised about raise of fundamantalists. Drop more bombs, kill more people, be surprised about them taking revenge and drop even more bombs and strip your own citizens of their rights and freedoms. to be continued
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