Gas Optimizations

[code423n4]

1. If use Offer memory offer and return offer is cheaper.

• NFTMarketOffer.sol#L388

2. Use delete instead of set the default value (false or 0)

• SendValueWithFallbackWithdraw.sol#L50

[HardlyDifficult]

Thanks for the feedback.

1. We decided to keep returning the unpacked version because this approach shields consumers from the slot packing strategy we use, and allows us to potentially make other additions or changes to the struct without impacting the external ABI. Ideally we would be more consistent here and do the same when returning the ReserveAuction struct - however there is a 3rd party contract which has already created a dependency on the current ABI.

2. We agree with this change as it improves readability and will switch to delete pendingWithdrawals[user] here.

[alcueca]

Wouldn't it be cheaper to do Offer memory offer = and then return (offer.buyer, offer.expiration, offer.amount)? The slot is warm, but still you should save about 300 gas.

Score: 300