Re: [PATCH] Add function to_oct

On Sat, Aug 19, 2023 at 08:35:46AM +0100, Dean Rasheed wrote:
> I note that there are no tests for negative inputs.

I added some in v8.

> Doing a quick test, shows that this changes the current behaviour,
> because all inputs are now treated as 64-bit:
> 
> HEAD:
> 
> select to_hex((-1234)::int);
>   to_hex
> ----------
>  fffffb2e
> 
> With patch:
> 
> select to_hex((-1234)::int);
>       to_hex
> ------------------
>  fffffffffffffb2e

Good catch.  In v8, I fixed this by first casting the input to uint32 for
the 32-bit versions of the functions.  This prevents the conversion to
uint64 from setting the rest of the bits.  AFAICT this behavior is pretty
well defined in the standard.

> The way that negative inputs are handled really should be documented,
> or at least it should include a couple of examples.

I used your suggestion and noted that the output is the two's complement
representation [0].

[0] https://postgr.es/m/CAEZATCVbkL1ynqpsKiTDpch34%3DSCr5nnau%3DnfNmiy2nM3SJHtw%40mail.gmail.com

-- 
Nathan Bossart
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