Tracking issue for integer methods for Wrapping #32463
Description
u32 and other primitive integer types implement a number of bit-manipulation methods like rotate_left, but Wrapping<_> does not. At the moment this can be worked around with code like Wrapping(x.0.rotate_left(n)) instead of x.rotate_left(n).
It would be nice to implement:
-
count_ones -
count_zeroes -
leading_zeroes -
trailing_zeroes -
rotate_left -
rotate_right -
swap_bytes -
from_be(?) -
from_le(?) -
to_be -
to_le -
pow(?)
Edit: Others added after #32463 (comment)
-
is_power_of_two(?) -
next_power_of_two(?) -
min_value(?) -
max_value(?) -
from_str_radix(?) -
reverse_bits -
absAdd missing Wrapping methods, use doc_comment! #49393Add missing Wrapping methods, use doc_comment! #50465 -
signumAdd missing Wrapping methods, use doc_comment! #49393Add missing Wrapping methods, use doc_comment! #50465 -
is_positiveAdd missing Wrapping methods, use doc_comment! #49393Add missing Wrapping methods, use doc_comment! #50465 -
is_negativeAdd missing Wrapping methods, use doc_comment! #49393Add missing Wrapping methods, use doc_comment! #50465
and maybe other methods, for:
Wrapping<u8>Wrapping<u16>Wrapping<u32>Wrapping<u64>Wrapping<usize>Wrapping<i8>Wrapping<i16>Wrapping<i32>Wrapping<i64>Wrapping<isize>
Edit: From #50465
- Decide on correct behavior for
wrapping_next_power_of_two
Activity
srinivasreddy commentedon Mar 24, 2016
I want to take this. Would you review my PR?
SimonSapin commentedon Mar 25, 2016
I can have a look, but I’m not one of the reviewers who can approve PRs for merging into this repository.
srinivasreddy commentedon Mar 25, 2016
sure that helps. thanks.
dtolnay commentedon Nov 17, 2017
I would be open to considering a PR that adds these methods.
Impl Integer methods for Wrapping
Rollup merge of rust-lang#48810 - Phlosioneer:32463-impl-integer-for-…
Rollup merge of rust-lang#48810 - Phlosioneer:32463-impl-integer-for-…
Impl Integer methods for Wrapping
24 remaining items
scottmcm commentedon Nov 24, 2020
Note that
next_power_of_twois already stable as wrapping to0in release mode, so I think it would be very surprising forwrapping_next_power_of_twoto do anything different. (Regardless of which answer is actually better.)If people want that, I would encourage them to propose it as a separate method. It's nicer than
next_power_of_twosince it has no overflow hazards, so doesn't need the full checked/wrapping/saturating set.Strawman for a bikeshed:
fill_lower_bits.mjbshaw commentedon Mar 17, 2021
Is there still debate around the behavior of
wrapping_next_power_of_two? I think thatnext_power_of_twoevaluates to 0 (in release mode) on overflow pretty much requires thatwrapping_next_power_of_twodoes the same; it'd be insanely surprising to behave differently.If there is a debate around this, how can I get involved to push for stabilization?
Rollup merge of rust-lang#85177 - tspiteri:wrapping-bits, r=joshtriplett
gendx commentedon Jul 21, 2023
Seconding @briansmith 's comment from soon 5 years ago, is there anything blocking stabilization of the basic and uncontroversial methods like
rotate_left|right,count_zeroes|ones, etc.?It doesn't seem to me that requiring the nightly compiler is justified for trivial 1-line methods that have been around for many years now.
Given the lack of discussion here, can one directly send a PR to stabilize some methods?
dlight commentedon May 27, 2024
How can this be driven forward? Right now
Wrappingis less useful than it should be.I hope so!
bjoernager commentedon Feb 24, 2025
Would it make sense to make this also include the recently-stabilised
cast_unsignedandcast_signed(tracking issue #125882)?Pr0methean commentedon Jan 11, 2026
Could Wrapping please also implement
From<T>andFrom<Wrapping<T>>for all the integer types?x.0 asfor narrowing isn't as readable, and it makes tools complain about the overflow.Apersoma commentedon Apr 17, 2026
Could we also get the
getfunction thatNonZerohas so that macros could take either?