From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>,
        Alvaro Herrera <alvherre@2ndquadrant.com>,
        Andres Freund <andres@anarazel.de>, James Coleman <jtc331@gmail.com>,
        PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #16104: Invalid DSA Memory Alloc Request in Parallel Hash
In-reply-to: 
 <CA+hUKGLFdtOtrB-Nx0Rhqw8tLR-DiTqPv+cRqVMTRc35a48-QA@mail.gmail.com>
References: <20191210173224.y5vaam6ep7pjmddt@development>
 <20191210173516.GA10987@alvherre.pgsql>
 <20191210183606.t26c5ypa7bmij3ph@development>
 <CA+hUKGK3g7SQ7_KfKm2uNFF6LoLwTy1-x8CLXsV5KA-rxW6F9g@mail.gmail.com>
 <CA+hUKGKA+tKg1v29=mfxbTkXSoRdFTzmD3R0U2YgwxRxLbLtMA@mail.gmail.com>
 <29716.1576905031@sss.pgh.pa.us>
 <CA+hUKGLFdtOtrB-Nx0Rhqw8tLR-DiTqPv+cRqVMTRc35a48-QA@mail.gmail.com>
Comments: In-reply-to Thomas Munro <thomas.munro@gmail.com>
	message dated "Sat, 21 Dec 2019 20:43:05 +1300"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <12105.1576940525.1@sss.pgh.pa.us>
Date: Sat, 21 Dec 2019 10:02:05 -0500
Message-ID: <12106.1576940525@sss.pgh.pa.us>
Precedence: bulk

Thomas Munro <thomas.munro@gmail.com> writes:
> Yeah, I suppose it would be nice to get something reusable out of this
> rather than a local definition only.  The other important
> characteristic is the direction of rotation, so here's a version that
> defines pg_rotate_right32() in pg_bitutils.h.  In back-branches
> without that header we could define it locally.

That looks like a good approach.  One thought is that you could rely
on BITS_PER_BYTE from c.h, rather than CHAR_BIT; then you don't have
to #include <limits.h> in bitutils.h, which seems like header creep
we could do without.  (I think most other places that want this
constant use BITS_PER_BYTE, too.)

			regards, tom lane