feat: improve poseidon API

[varun-doshi]

Pull Request type

What is the current behavior?

StarkHash trait does have hash_single funciton

Resolves: #107

What is the new behavior?

• StarkHash now implements hash_single function

Does this introduce a breaking change?

No

Other information

This results in Pedersen needing to implement hash_single as well. Currently, it is set as todo!

[tdelabro]

@varun-doshi need any help?

[varun-doshi]

@varun-doshi need any help?

I'm not sure how to go about hash_single for Pedersen...since it's now in the trait for both Poseidon and Pedersen hence it needs to be implemented as well.

I can open this PR for review if that'll help?

[tdelabro]

@varun-doshi I think the pedersen hash_single impl should be pedersen(0, value)

[tdelabro]

@varun-doshi let's go with pedersen(value, 0) (based on @liorgold2 feedbacks) and make it very explicit in the documentation that there is room for collision as:
pedersen(value) and pedersen(value, 0) will return the same values
and
pedersen_array([value]) and pedersen(pedersen(0, value), 1) will too

Add the first example to the hash_single doc and the second one to the hash_array doc

[tdelabro]

@varun-doshi it looks like your branch fails to build. Can you check what is going wrong?

[varun-doshi]

@varun-doshi it looks like your branch fails to build. Can you check what is going wrong?

@tdelabro it seems that command is running successfully on my local. This is build error showing up on CI

error: package `parity-scale-codec v3.7.1` cannot be built because it requires rustc 1.79.0 or newer, while the currently active rustc version is 1.77.2
Either upgrade to rustc 1.79.0 or newer, or use
cargo update parity-scale-codec@3.7.1 --precise ver
where `ver` is the latest version of `parity-scale-codec` supporting rustc 1.77.2

Is it possible its a CI issue? Pls correct me if im wrong

[tdelabro]

@varun-doshi I will suggest you update https://github.com/starknet-io/types-rs/blob/main/rust-toolchain.toml
setting the toolchain to the latest rust release 1.84.1

[varun-doshi]

@tdelabro updating the toolchain version of this PR back to 1.80.1(which is what is on main right now) after you confirm
Currently this PR is on 1.84.1 as you had suggested

[jbcaron]

@tdelabro updating the toolchain version of this PR back to 1.80.1(which is what is on main right now) after you confirm Currently this PR is on 1.84.1 as you had suggested

The CI passing with version 1.80.1.