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Re: [PATCH 1/2] add MOVE_ARRAY




On Sat, Jul 15, 2017 at 09:36:20PM +0200, René Scharfe wrote:

> Similar to COPY_ARRAY (introduced in 60566cbb58), add a safe and
> convenient helper for moving potentially overlapping ranges of array
> entries.  It infers the element size, multiplies automatically and
> safely to get the size in bytes, does a basic type safety check by
> comparing element sizes and unlike memmove(3) it supports NULL
> pointers iff 0 elements are to be moved.
> 
> Also add a semantic patch to demonstrate the helper's intended usage.

If we have COPY_ARRAY(), I think it's foolish not to provide the
matching MOVE_ARRAY().  If it were just the "if (n)", I might say we
could just do this inline in the few calls that care.  But I really like
the size safety.

I agree with your comments elsewhere that we don't need to worry about
the case where one of the arrays is NULL but the size is not zero.
That's a flat-out bug.

-Peff