ENS contest - ElKu's results

1) Avoid floating pragmas.

Instances include all the files under scope.

1. pragma solidity ^0.8.4;
2. pragma solidity ^0.8.4;
3. pragma solidity ^0.8.4;
4. pragma solidity >=0.8.4;
5. pragma solidity ^0.8.4;
6. pragma solidity ^0.8.4;
7. pragma solidity ^0.8.4;
8. pragma solidity ^0.8.4;
9. pragma solidity >=0.8.4;
10. pragma solidity >=0.8.4;
11. pragma solidity >=0.8.4;
12. pragma solidity >=0.8.4;
13. pragma solidity >=0.8.4;
14. pragma solidity >=0.8.4;
15. pragma solidity ^0.8.4;
16. pragma solidity ^0.8.4;
17. pragma solidity >=0.8.4;
18. pragma solidity >=0.8.4;
19. pragma solidity >=0.8.4;
20. pragma solidity ^0.8.4;

2) For readability’s sake, use uint256 explicitly instead of uint.

Multiple instances in the following files:

1. DNSSECImpl.sol
2. BytesUtils.sol
3. RRUtils.sol
4. StringUtils.sol
5. BytesUtil.sol

Use unchecked arithmetic for arithmetical operations which will never overflow or underflow.

This includes the increment of the loop indices, which most probably will never overflow.

1. for (uint idx = 0; idx < shortest; idx += 32)
2. for(uint i = 0; i < len; i++)
3. for(uint256 idx = off; idx < off + len; idx++)
4. len % 8 in these if-else statements can be pre computed to save gas.
5. for(uint i = 0; i < input.length; i++)
6. idx += labelLen + 1;
7. offset += labelLen + 1;
8. count += 1;
9. counts -= 1;
10. return off + 1 + body.readUint8(off);
11. for(uint i = 0; i < data.length + 31; i += 32)
12. uint unused = 256 - (data.length - i) * 8;
13. for (uint256 i = 0; i < data.length; i++)
14. The whole of for loop block can be placed inside unchecked.
15. for (uint256 i = 0; i < accounts.length; ++i)
16. for (uint256 i = 0; i < ids.length; ++i)
17. This calculation: (8 * (32 - shortest + idx)) can be placed inside an unchecked variable. But you would need to declare a temporary variable to hold the value.