Gas Optimizations

[code423n4]

#1 Cache _implementations.length

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L81

cache the _implementations.length to the local too for saving the gas fee. because mload is cheaper than sload.

#2 cache _contractAddresses.length

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L133

cache the _contractAddresses.length to the local too for saving the gas fee. because mload is cheaper than sload.

#3 looping

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L87

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L136

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L248

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L311

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L322

default value uint is 0 so remove unnecassary explicit can reduce gas.
pre increment e.g ++i more cheaper gas than post increment e.g i++. i suggest to use pre increment.

#4 use !=0 instead of >0

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L108

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L195

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L764

for unsigned integer, >0 is less efficient then !=0, so use !=0 instead of >0.
apply to others.

#5 use storage instead of memory

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L591

Use storage instead of memory to reduce the gas fee. i suggest to change this.

#6 visibility

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L60

change visibility from public to private or internal can save gas. so i recommend to change it.

#7 cache _taskCosts.length

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L245

cache the _taskCosts.length to the local too for saving the gas fee. because mload is cheaper than sload.

#8 cache _scList.length

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L308

cache the _scList.length to the local too for saving the gas fee. because mload is cheaper than sload.

#9 cache _changeOrderedTask.length

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L592

cache the _changeOrderedTask.length to the local too for saving the gas fee. because mload is cheaper than sload.

#10 pre increment

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L625

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L672

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L140

pre-increment more cheap than post increment about 5 gas. so use pre increment e.g. ++i

#11 use calldata instead memory

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L878

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L761

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L874

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/SignatureDecoder.sol#L22

https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/SignatureDecoder.sol#L61

In the external functions where the function argument is read-only, the function() has an inputed parameter that using memory, if this function didnt change the parameter, its cheaper to use calldata then memory. so we suggest to change it.