Unstructured storage demo (mapping to structs)

StructMappingDemo.sol

pragma solidity ^0.6.0;

contract StructMappingDemo {
    bytes32 internal constant NOP_MAPPING_POSITION = keccak256("org.test.storagedemo.nopMapping");
    
    struct NodeOperator {
        bool active;
        address rewardAddress;
        string name;
    }
    
    function getNopMapping(bytes32 _position) internal view returns (mapping(uint256 => NodeOperator) storage result) {
        assembly {
            result_slot := _position
        }
    }
    
    function getOp(uint256 _id) public view returns (bool active, address rewardAddress, string memory name) {
        mapping(uint256 => NodeOperator) storage ops = getNopMapping(NOP_MAPPING_POSITION);
        NodeOperator storage op = ops[_id];
        active = op.active;
        rewardAddress = op.rewardAddress;
        name = op.name;
    }
    
    function setOp(uint256 _id, bool _active, address _rewardAddress, string memory _name) public {
        mapping(uint256 => NodeOperator) storage ops = getNopMapping(NOP_MAPPING_POSITION);
        NodeOperator storage op = ops[_id];
        op.active = _active;
        op.rewardAddress = _rewardAddress;
        op.name = _name;
    }
}