Add Solidity Keccak256 packing support

[Ethan-000]

Hi. Is anyone working on adding Solidity Keccak256 packing support?

/// Compute the Keccak-256 hash of input bytes.
// TODO: Add Solidity Keccak256 packing support
pub fn keccak256<S>(bytes: S) -> [u8; 32]
where
    S: AsRef<[u8]>,
{
    let mut output = [0u8; 32];
    let mut hasher = Keccak::v256();
    hasher.update(bytes.as_ref());
    hasher.finalize(&mut output);
    output
}

In ethers-js, its here
https://github.com/ethers-io/ethers.js/blob/master/packages/bytes/src.ts/index.ts.

I don't know rust or the package well enough to add this myself. It could be helpful if someone can do this. Thanks!

[Ethan-000]

found the abi.encode and get_create2_address function sorry.

[Ethan-000]

eh I think no abi pack util so I'll reopen

[tynes]

Do you mean abi.encodePacked?

[Ethan-000]

yes

[cbrzn]

hey just wanted to share that would be awesome if this function is developed :-), if someone would like to deeply interact with safe factory contracts, they will need this (to generate salt)

[DaniPopes]

Actually it already is present as abi::encode_packed: https://github.com/gakonst/ethers-rs/blob/master/ethers-core/src/abi/packed.rs

It just hasn't been released yet

@gakonst we can close this, same as #1862