Functions are more efficient in solidity when their function selector has mostly zeros.
For example
deposit278591A(uint256) has a function selector of 00000070
but deposit(uint256) has a function selector of b6b55f25
The function selector is computed as the first 4 bytes of the keccak256 of the function signature. The function signature excludes the variable names. For example, sendValue(uint256 amount) is not correct but sendValue(uin256) is.
The gas cost of a function name is 4 times the number of zero bytes, and 16 times the number of nonzero bytes. So in the worst case, the gas cost is 64 gas (4 non-zero bytes), and in the best case 28 gas (3 zero and 1 non-zero). An all zero function selector won't compile because that conflicts with the fallback function. Thus, mint_22F5A30(uint256) is more efficient than mint(uint256)
If the zeros are leading zeros, this will make the contract smaller and save gas on deployment.
https://www.rust-lang.org/tools/install
cargo build --release
./target/release/eth-zero-finder "myFunctionName?(uint,address,...)" <num threads> (true|false)
The question mark will be substituted with a hex number found by searching. Your function should follow the format for solidity function selectors. Eg: No arguments: "myFunction()". One address argument: "myFunction(address)". Two arguments: "anotherFunction(uint256,address)" etc.
Num threads is the number of threads to use. The final true false is if you want to force the zeros to be leading zeros. Leading zeros lead to a lower gas cost on deployment.
The search usually finds a solution in less than 30 seconds on a macbook pro with 8 threads.
Example run:
./target/release/eth-zero-finder "withdraw_?()" 8 true
