Gas Optimizations

[code423n4]

G001 - 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. https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L556

for (uint256 i = 0; i < orders.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L594

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L611

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L627

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L637

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L647

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L658

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L670

for (uint256 i = 0; i < whitelist.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L728

for (uint256 i = 0; i < arr.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L742

for (uint256 i = 0; i < arr.length; i++) {

G003 - Use != 0 instead of > 0 for Unsigned Integer Comparison

Description

When dealing with unsigned integer types, comparisons with != 0 are cheaper then with > 0.

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L293

require(order.baseAsset.code.length > 0, "baseAsset is not contract");

G011 - Unnecessary checked arithmetic in for loop

++i/i++ should be unchecked{++i}/unchecked{++i} when it is not possible for them to overflow, as is the case when used in for- and while-loops

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L556

for (uint256 i = 0; i < orders.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L594

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L611

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L627

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L637

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L647

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L658

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L670

for (uint256 i = 0; i < whitelist.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L728

for (uint256 i = 0; i < arr.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L742

for (uint256 i = 0; i < arr.length; i++) {

G012 - Use Prefix Increment instead of Postfix Increment if possible

Description

The difference between the prefix increment and postfix increment expression lies in the return value of the expression.

The prefix increment expression ++i returns the updated value after it's incremented. The postfix increment expression i++ returns the original value.

The prefix increment expression is cheaper in terms of gas.

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L556

for (uint256 i = 0; i < orders.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L594

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L611

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L627

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L637

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L647

for (uint256 i = 0; i < assets.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L658

for (uint256 i = 0; i < floorTokens.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L670

for (uint256 i = 0; i < whitelist.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L728

for (uint256 i = 0; i < arr.length; i++) {

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L742

for (uint256 i = 0; i < arr.length; i++) {

DUPLICATED REQUIRE()/REVERT() CHECKS SHOULD BE REFACTORED TO A MODIFIER OR FUNCTION

Saves deployment costs

https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L395

require(ownerOf(uint256(orderHash)) == msg.sender, "Not owner");