Infinity NFT Marketplace contest - slywaters's results

Gas Report

Variables do not need to be initialized with 'empty' values such as 0, false, or address(0)

Uninitialized variables by default contain a value equivalent to 0: uints are initialized to 0; bools to false; addresses to address(0).

Explicitly assigning these values to variables when they are declared increases gas costs while providing no funciton.

e.g. change this code:

uint256 var = 0;

to

uint256 var;

For more information, please consult the following resources:

Tips and Tricks to Save Gas and Reduce Bytecode Size

The following lines of code are affected:

2022-06-infinity/contracts/core/InfinityExchange.sol:1048:    for (uint256 i = 0; i < numNfts; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:1086:    for (uint256 i = 0; i < numTokens; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:1109:    for (uint256 i = 0; i < numNfts; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:1190:    for (uint256 i = 0; i < numNfts; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:1206:    for (uint256 i = 0; i < numTokens; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:148:    for (uint256 i = 0; i < numMakerOrders; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:200:      for (uint256 i = 0; i < ordersLength; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:219:      for (uint256 i = 0; i < ordersLength; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:272:    for (uint256 i = 0; i < numSells; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:308:    for (uint256 i = 0; i < numMakerOrders; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:349:    for (uint256 i = 0; i < ordersLength; ) {
2022-06-infinity/contracts/core/InfinityExchange.sol:393:    for (uint256 i = 0; i < numNonces; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:197:    uint256 numConstructedItems = 0;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:199:    for (uint256 i = 0; i < nftsLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:214:    uint256 numTakerItems = 0;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:216:    for (uint256 i = 0; i < nftsLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:244:    uint256 numCollsMatched = 0;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:246:    for (uint256 i = 0; i < order2NftsLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:247:      for (uint256 j = 0; j < order1NftsLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:289:    uint256 numTokenIdsPerCollMatched = 0;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:290:    for (uint256 k = 0; k < item2TokensLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:291:      for (uint256 l = 0; l < item1TokensLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:318:    uint256 sum = 0;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:320:    for (uint256 i = 0; i < ordersLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:76:    for (uint256 i = 0; i < ordersLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:82:      for (uint256 j = 0; j < nftsLength; ) {
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:108:    bool _isPriceValid = false;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:42:    bool _isPriceValid = false;

"calldata" can be used instead of "memory" to reduce gas costs

Both memory and calldata allow a developer to manage variables within the scope of a function. memory is mutable which makes it a more flexible tool; however, it costs additional gas when compared with calldata. calldata is non-modifiable but cheaper. Therefore it is recommended to use calldata for function parameters when they will not be modified.

For more information, see the following resources: Solidity Documentation recommending the use of calldata

Solidity — Storage vs Memory vs Calldata

The following function call can be changed to use calldata instead of memory:

2022-06-infinity/contracts/token/TimelockConfig.sol:76:  function calculateConfigId(string memory name) external pure returns (bytes32 configId) {

Use strict less-than/greather-than comparisons rather than less-than-or-equal/greater-than-or-equal

When compiled, Solidity code using the >= or <= comparison operators in fact executes two separate checks: one for 'is-equal-to' and a second for 'is-greater-than/is-less-than'. By contrast, using > or < performs only one check. Therefore code that is written to use strict comparison operators is more gas-efficient.

If this change is applied, be sure to update the relevant variables being evaluated. For clarity, it is also advised to rename the variables to make this change explicit, e.g. renaming a variable from MINIMUM to MINIMUM_PLUS_ONE.

The following lines are affected:

2022-06-infinity/contracts/core/InfinityExchange.sol:311:      bool isTimeValid = makerOrders[i].constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityExchange.sol:312:        makerOrders[i].constraints[4] >= block.timestamp;
2022-06-infinity/contracts/core/InfinityExchange.sol:326:      require(msg.value >= totalPrice, 'invalid total price');
2022-06-infinity/contracts/core/InfinityExchange.sol:362:      require(msg.value >= totalPrice, 'invalid total price');
2022-06-infinity/contracts/core/InfinityExchange.sol:394:      require(orderNonces[i] >= userMinOrderNonce[msg.sender], 'nonce too low');
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:102:      makerOrder.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:103:      makerOrder.constraints[4] >= block.timestamp;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:110:      _isPriceValid = sumCurrentOrderPrices >= currentMakerOrderPrice;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:112:      _isPriceValid = sumCurrentOrderPrices <= currentMakerOrderPrice;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:160:    return (makerOrder.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:161:      makerOrder.constraints[4] >= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:175:      sell.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:176:      sell.constraints[4] >= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:177:      buy.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:178:      buy.constraints[4] >= block.timestamp;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:188:    return (currentBuyPrice >= currentSellPrice, currentSellPrice);
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:205:    return numConstructedItems >= buy.constraints[0] && buy.constraints[0] <= sell.constraints[0];
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:38:    bool _isTimeValid = makerOrder2.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:39:      makerOrder2.constraints[4] >= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:40:      makerOrder1.constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:41:      makerOrder1.constraints[4] >= block.timestamp;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:47:      _isPriceValid = makerOrder2Price >= makerOrder1Price;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:50:      _isPriceValid = makerOrder1Price >= makerOrder2Price;
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:91:        manyMakerOrders[i].constraints[3] <= block.timestamp &&
2022-06-infinity/contracts/core/InfinityOrderBookComplication.sol:92:        manyMakerOrders[i].constraints[4] >= block.timestamp;
2022-06-infinity/contracts/libs/SignatureChecker.sol:28:      uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
2022-06-infinity/contracts/staking/InfinityStaker.sol:123:    require(totalVested >= amount, 'insufficient balance to unstake');
2022-06-infinity/contracts/staking/InfinityStaker.sol:193:    require(totalStaked >= 0, 'nothing staked to rage quit');
2022-06-infinity/contracts/staking/InfinityStaker.sol:213:    if (totalPower <= BRONZE_STAKE_THRESHOLD) {
2022-06-infinity/contracts/staking/InfinityStaker.sol:215:    } else if (totalPower > BRONZE_STAKE_THRESHOLD && totalPower <= SILVER_STAKE_THRESHOLD) {
2022-06-infinity/contracts/staking/InfinityStaker.sol:217:    } else if (totalPower > SILVER_STAKE_THRESHOLD && totalPower <= GOLD_STAKE_THRESHOLD) {
2022-06-infinity/contracts/staking/InfinityStaker.sol:219:    } else if (totalPower > GOLD_STAKE_THRESHOLD && totalPower <= PLATINUM_STAKE_THRESHOLD) {
2022-06-infinity/contracts/staking/InfinityStaker.sol:270:    return secondsSinceStake >= durationInSeconds ? amount : 0;
2022-06-infinity/contracts/staking/InfinityStaker.sol:69:    require(IERC20(INFINITY_TOKEN).balanceOf(msg.sender) >= amount, 'insufficient balance to stake');
2022-06-infinity/contracts/staking/InfinityStaker.sol:93:      userstakedAmounts[msg.sender][oldDuration].amount >= amount,
2022-06-infinity/contracts/token/InfinityToken.sol:62:    require(block.timestamp >= currentEpochTimestamp + getCliff(), 'cliff not passed');
2022-06-infinity/contracts/token/InfinityToken.sol:63:    require(block.timestamp >= previousEpochTimestamp + getEpochDuration(), 'not ready to advance');
2022-06-infinity/contracts/token/TimelockConfig.sol:52:    require(block.timestamp >= _pending[configId].timestamp + _config[TIMELOCK], 'too early');

Split require() calls using && into separate statements

Using && operations within require() statements increases gas costs. Separate these conditions into separate require() calls.

The following require() statements should be refactored:

2022-06-infinity/contracts/core/InfinityExchange.sol:264:    require(numSells == buys.length && numSells == constructs.length, 'mismatched lengths');
2022-06-infinity/contracts/core/InfinityExchange.sol:949:    require(makerOrderValid && executionValid, 'order not verified');