feat: Implementation of the SizeOf<T> trait

[akhercha]

Feature Request

Describe the Feature Request

Introduction of a SizeOf<T> trait designed to retrieve the size in bits of various data types.

Describe Preferred Solution

trait SizeOf<T> {
    /// Returns the size in bits of T. 
    fn size() -> T;
    /// Returns the size in bits of Self.
    fn size_of(self: @T) -> T;
}

impl U8SizeOf of SizeOf<u8> {
    fn size() -> u8 {
        8
    }
    fn size_of(self: @u8) -> u8 {
        U8SizeOf::size()
    }
}

After implemented for u8 for example, it would be then:

assert(10_u8.size_of() == 8, 'should be 8');
// or
assert(U8SizeOf::size() == 8, 'should be 8');

Related Code

Implemented in Kakarot::utils::num for PR #410

The usage was:

fn shl(self: T, shift: T) -> T {
        if shift > shift.size_of() - One::one() {
            panic_with_felt252('mul Overflow');
        }
        (...)
    }

Additional Context

If the feature request is approved, would you be willing to submit a PR?

• Yes
• No

[orizi]

this is not "size" - this might be "representation bits" - "size" implies the size in memory.
but asside from that sounds fine.