[U-Boot] [PATCH V2] memcpy/memmove: Do not copy to same address

Wolfgang Denk
2011-05-23T21:55:33Z

Dear Alexander Holler,

In message <4DDACC8B.6090507@ahsoftware.de> you wrote:
>
> > --- a/lib/string.c
> > +++ b/lib/string.c
> > @@ -467,6 +467,9 @@ void * memcpy(void *dest, const void *src, size_t count)
> > unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
> > char *d8, *s8;
> >
> > + if (src == dest)
> > + return dest;
> > +
>
> here is the same, as in the patch I've commented before. There exist no
> reason to add a check for identity to memcpy() because memcpy doesn't
> support overlapping regions (and identity is just a special case of
> overlapping regions). If something might call memcpy() with overlapping
> or identical regions, it should use memmove().

In an ideal world, nobody will ever use any interfces in a
non-compliant or incorrect way.

In reality, all kind of errors happen. A little defensive programming
like the one above helps a lot, so please stop complaining even if you
think you don't need this.

Thanks.

Wolfgang Denk

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