Mini ENS smart contract

ens.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

contract ENS {
    mapping(address => bytes) public AddressToBytesNames;
    mapping(bytes => address) public bytesNameToAddress;
    uint public TotalRegAddr = 0;


    event registerAlert(address, string);
    event NameChange(address, string);



    function register(address _address, string memory _name) public {
        bytes memory _empty;
        bytes memory callerName = AddressToBytesNames[_address];
        require(keccak256(abi.encodePacked(callerName)) == keccak256(abi.encodePacked(_empty)), "This address has an existing name");
        require(bytesNameToAddress[bytes(_name)] == address(0), "This name has been registered");
        AddressToBytesNames[_address] = bytes(_name);
        bytesNameToAddress[bytes(_name)] = _address;
        TotalRegAddr += 1;
        emit registerAlert(_address, _name);
    }

    function getOwner(string memory _name) public view returns(address) {
        return bytesNameToAddress[bytes(_name)];
    }

    function getNamefromAddr(address _address) public view returns(string memory) {
        return string(AddressToBytesNames[_address]);
    }


    function changename(string memory _newName) public {
        bytes memory callerName = AddressToBytesNames[msg.sender];
        bytes memory _empty;
        require(keccak256(abi.encodePacked(callerName)) != keccak256(abi.encodePacked(_empty)), "You dont have any name assigned to you");
        delete(AddressToBytesNames[msg.sender]);
        delete(bytesNameToAddress[callerName]);
        TotalRegAddr -= 1;
        register(msg.sender, _newName);
        emit NameChange(msg.sender, _newName);
    }
}