Re: [PATCH] ihash ids should be unsigned

[Roland McGrath]

> the libihash ids are signed integers, but all users actually provide
> unsigned integers, and expect it to work.  If a large integer is provided
> that is cast to a negative number, the hash value will be negative as well,
> and there will be underflow errors (negative array indices).  I remember
> that Neal told me he actually saw that happening, but I don't know in what
> code it was (ours, or code he was hacking) and under which situation. 
> Anyway, it's apparently wrong.  Neal seems to like to use unsigned long
> instead, which would give 64 bit on 64 bit arches, but I am more
> conservative and provide this patch which uses unsigned int.

Sounds good.  I am sort of inclined to switch to uint32_t or something like
that.  I don't think there would be a problem using uintptr_t (long) and
having 64 bits on 64-bit machines.  But it doesn't buy you anything, since
it's used mostly for PIDs (pid_t = int = 32 bits) and port names
(mach_port_t = unsigned = 32 bits).

> I also want to remove ihash/primes.c which is obsolete but wasn't removed at
> the time Roland replaced it by sizes.c.  The file will still be in the
> repository, of course (under Attic).

Fine.