Gas: Avoid expensive calculation by checking if `originalLiquidity() == 0`

[code423n4]

Handle

Dravee

Vulnerability details

Impact

Checking if the value is 0 before returning 0 is less expensive than returning a calculation that's equal to 0

Proof of Concept

In PoolTemplate.sol:rate(), the code is as follows:

File: PoolTemplate.sol
744:     function rate() external view returns (uint256) {
745:         if (totalSupply() > 0) {
746:             return (originalLiquidity() * MAGIC_SCALE_1E6) / totalSupply();
747:         } else {
748:             return 0;
749:         }
750:     }

It can be optimized as such:

744:     function rate() external view returns (uint256) {
745:         uint256 originalLiquidity = originalLiquidity();
746:         if (originalLiquidity != 0 && totalSupply() > 0) {
747:             return (originalLiquidity * MAGIC_SCALE_1E6) / totalSupply();
748:         } else {
749:             return 0;
750:         }
751:     }

Tools Used

VS Code

Recommended Mitigation Steps

Cache the loaded storage value in a memory variable and make the 0 checks to avoid unnecessary calculations if originalLiquidity() == 0