Gas Optimizations

[code423n4]

G-01 Use defualt value rather than overwriite variable with their default value.

Overriting varibles with defualt values with their default value will waste only gas and not necessary.

There are 7 instances of this issue:

File: ArtGobblers.sol lines 432, 592

for (uint256 i = 0; i < cost; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L432

for (uint256 i = 0; i < numGobblers; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L592

File: Pages.sol line 251

for (uint256 i = 0; i < numPages; i++) _mint(community, ++lastMintedPageId);

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/Pages.sol#L251

File: GobblerReserve.sol line 37

2022-09-artgobblers/src/utils/GobblerReserve.sol::37 => for (uint256 i = 0; i < ids.length; i++) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/GobblerReserve.sol#L37

File: GobblersERC1155B lines 114,173

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

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC1155B.sol#L114

for (uint256 i = 0; i < amount; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC1155B.sol#L173

File: GobblersERC721 line 186

for (uint256 i = 0; i < amount; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC721.sol#L186

G-02 In for loop use outside variable for array length

For loop written like thisfor (uint256 i; i < array.length; ++i) { will cost more gas than for (uint256 i; i < _lengthOfArray; ++i) { because for every iteration we use mload and memory_offset that will cost about 6 gas

There are 2 instances of this issue:

File: GobblerReserve.sol: line 37

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

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/GobblerReserve.sol#L37

File GobblersERC1155B.sol line 114

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

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC1155B.sol#L114

G-03 If you use bit shifting will save some gas

Use of bit shifting operations are more cheap than normal multiplication/division operations. MUL and DIV costs 5 gas rather than SHL and SHR that costs 3 gas. You can use them where is possible

There are 2 instances of this issue:

File: ArtGobblers.sol lines 449,462

getGobblerData[gobblerId].emissionMultiple = uint32(burnedMultipleTotal * 2);

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L449

2022-09-artgobblers/src/ArtGobblers.sol::462 => cost <= LEGENDARY_GOBBLER_INITIAL_START_PRICE / 2 ?

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L462

G-05 i++, i += 1 and i = i + 1 IN FOR LOOPS COSTS MORE GAS COMPARED TO ++i

++i will save about 5 gas for each iteration

There are 2 instances of this issue:

File: Pages.sol line 251

for (uint256 i = 0; i < numPages; i++) _mint(community, ++lastMintedPageId);

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/Pages.sol#L251

File: GobblerReserve.sol line 37

2022-09-artgobblers/src/utils/GobblerReserve.sol::37 => for (uint256 i = 0; i < ids.length; i++) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/GobblerReserve.sol#L37

G-06 Recomend to use uint256(1)/uint256(2) for true and false

If you don't use boolean for storage you will avoid Gwarmaccess (100 gas). Also boolean from true to false cost 20000 gas rather than uint256(2) to uint256(1) that cost less.

There have 4 istance of this issues:

mapping(address => mapping(address => bool)) public isApprovedForAll;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC721.sol#L77

mapping(address => bool) public hasClaimedMintlistGobbler;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L149

bool waitingForSeed;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L212

mapping(address => mapping(address => bool)) internal _isApprovedForAll;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/PagesERC721.sol#L70

G-07 Recomend to use one operator for comparison where is possible

If you use >= or <= this will cost more gas because in the EVM there is no implementation of Opcodes for >= and `<= and two operations are done.

There have 4 istance of this issues:

if (numMintedSinceStart >= LEGENDARY_AUCTION_INTERVAL) return 0;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L435

if (numMintedSinceStart >= LEGENDARY_AUCTION_INTERVAL) return 0;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L497

if (gobblerId <= gobblerRevealsData.lastRevealedId) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L695

if (gobblerId <= currentNonLegendaryId) return UNREVEALED_URI;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L702

G-04 = + cost less than += for state variables

There have 2 istance of this issues:

burnedMultipleTotal += getGobblerData[id].emissionMultiple;

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L439

legendaryGobblerAuctionData.numSold += 1; // Increment the # of legendaries sold.

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L464

G-03 Use uncheck() in for loops whenere overflow and undeflow is not possible

Using of uncheck(i++)/uncheck(++i) will save about 30 gas per iteration because compiler not save check everytime. This feature come from 0.8

There are 7 instances of this issue:

File: ArtGobblers.sol lines 432, 592

for (uint256 i = 0; i < cost; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L432

for (uint256 i = 0; i < numGobblers; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/ArtGobblers.sol#L592

File: Pages.sol line 251

for (uint256 i = 0; i < numPages; i++) _mint(community, ++lastMintedPageId);

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/Pages.sol#L251

File: GobblerReserve.sol line 37

2022-09-artgobblers/src/utils/GobblerReserve.sol::37 => for (uint256 i = 0; i < ids.length; i++) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/GobblerReserve.sol#L37

File: GobblersERC1155B lines 114,173

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

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC1155B.sol#L114

for (uint256 i = 0; i < amount; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC1155B.sol#L173

File: GobblersERC721 line 186

for (uint256 i = 0; i < amount; ++i) {

https://github.com/code-423n4/2022-09-artgobblers/blob/d2087c5a8a6a4f1b9784520e7fe75afa3a9cbdbe/src/utils/token/GobblersERC721.sol#L186

[GalloDaSballo]

About 100 gas