Contract Source Code:

pragma solidity ^0.4.25;

contract MyWishEosRegister {
    event RegisterAdd(address indexed, string, bytes32);
    mapping(address => bytes32) private register;
    
    function put(string _eosAccountName) external {
        require(register[msg.sender] == 0, "address already bound");
        bytes memory byteString = bytes(_eosAccountName);
        require(byteString.length == 12, "worng length");

        for (uint i = 0; i < 12; i ++) {
            byte b = byteString[i];
            require((b >= 48 && b <= 53) || (b >= 97 && b <= 122), "wrong symbol");
        }
        bytes32 result;
        assembly {
            result := mload(add(byteString, 0x20))
        }
        register[msg.sender] = result;
        emit RegisterAdd(msg.sender, _eosAccountName, result);
    }

    
    function get(address _addr) public view returns (string memory result) {
        bytes32 eos = register[_addr];
        if (eos == 0) {
            return;
        }
        result = "............";
        assembly {
            mstore(add(result, 0x20), eos)
        }
    }

    
    function get() public view returns (string memory) {
        return get(msg.sender);
    }
}