Align with core/std on overflowing_sh*
#430
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Changes all shift functions which return an overflow flag (as a `Choice`
or `ConstChoice`) to use the `overflowing_sh*` name prefix, which aligns
with similar APIs in `core`/`std`.
In their place, adds new `Uint::{shl, shr}` functions which provide the
trait-like behavior (i.e. panic on overflow) but work in `const fn`
contexts (and can now panic at compile time on overflow).
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Note: the name changes were done using automated refactoring with IntelliJ, so I still haven't carefully gone through and determined what locations which are using |
| //! pub const MODULUS_SHR1: U256 = MODULUS.shr(1).0; | ||
| //! pub const MODULUS_SHR1: U256 = MODULUS.shr(1); |
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This feels like an ergonomics improvement
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There are a few API gaps which should probably be filled before merging if we're happy this, like every
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| @@ -5,9 +5,22 @@ use core::ops::{Shl, ShlAssign}; | |||
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| impl<const LIMBS: usize> Uint<LIMBS> { | |||
| /// Computes `self << shift`. | |||
| /// | |||
| /// Panics if `shift >= Self::BITS`. | |||
| pub const fn shl(&self, shift: u32) -> Self { | |||
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Do we even need these methods? Primitive types don't have them.
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It's what makes this possible, i.e. using them in a const fn context (and even better, doing compile-time overflow checking).
Primitive types are a bit magical in that arithmetic operators like << and >> work in const contexts even though for all other types they'd thunk through the Shl/Shr traits which won't be able to do that until const impl is available.
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LGTM, except that I think |
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Will fix. Thanks! |
Changes all shift functions which return an overflow flag (as a
ChoiceorConstChoice) to use theoverflowing_sh*name prefix, which aligns with similar APIs incore/std.In their place, adds new
Uint::{shl, shr}functions which provide the trait-like behavior (i.e. panic on overflow) but work inconst fncontexts (and can now panic at compile time on overflow).