On 06/02/2024 00.21, Kees Cook wrote: > > > On February 5, 2024 11:17:12 PM GMT, Eric Biggers <[email protected]> wrote: >> On Mon, Feb 05, 2024 at 02:44:14PM -0800, Kees Cook wrote: >>> On Mon, Feb 05, 2024 at 12:21:45PM -0800, Eric Biggers wrote: >>>> On Mon, Feb 05, 2024 at 01:12:30AM -0800, Kees Cook wrote: >>>>> Subject: Re: [PATCH v3 2/3] overflow: Introduce add_wrap(), sub_wrap(), >>>>> and mul_wrap() >>>> >>>> Maybe these should be called wrapping_add, wrapping_sub, and wrapping_mul? >>>> Those names are more grammatically correct, and Rust chose those names too. >>> >>> Sure, that works for me. What bout the inc_wrap() and dec_wrap() names? >>> I assume wrapping_inc() and wrapping_dec() ? >>> >> >> Yes, though I'm not sure those should exist at all. Maybe a += b should just >> become a = wrapping_add(a, b), instead of wrapping_inc(a, b)? >> wrapping_inc(a, b) isn't as self-explanatory. Likewise for wrapping_dec. > > It was to avoid repeating type information, as it would go from: > > var_a += var_b; > > to: > > var_a = wrapping_add(typeof(var_a), var_a, var_b); > > Which repeats "var_a" 3 times. :|
Yeah, I think that's a reasonable rationale. I'm fine with the wrapping_* naming, and then the _inc and _dec helpers should follow. However, I now wonder if those should really also return the new value. Yes, that corresponds to the value of the expression (a += b), but nobody would ever write c = (a += b) or otherwise make use of that value, and the naming doesn't immediately imply whether one should think of ++a or a++. Rasmus
