Gas Optimizations

[code423n4]

Don't Initialize Variables with Default Value

description

Uninitialized variables are assigned with the types default value.

Explicitly initializing a variable with it's default value costs unnecesary gas.

findings

File: Cally.sol
94:     uint256 public feeRate = 0;
95:     uint256 public protocolUnclaimedFees = 0;
282: uint256 fee = 0;

require statements should be checked first

description

require statements can be placed earlier to reduce gas usage on revert
ie move require to the top of the function if possible

findings

File: Cally.sol
269:         require(block.timestamp < vault.currentExpiration, "Option has expired");
272:         require(msg.value == vault.currentStrike, "Incorrect ETH sent for strike");

do not cache variable used only once

description

for variables only used once, changing it to inline saves gas

findings

File: Cally.sol
265: uint256 vaultId = optionId - 1;
333: uint256 optionId = vaultId + 1;

File: CallyNft.sol
44: address from = _ownerOf[id];