Solidity Verify Signature

VerifySign.sol

pragma solidity ^0.4.21;

contract VerifySign {

    function verify(bytes _msgHex, uint8 _v, bytes32 _r, bytes32 _s) public pure returns (address) {
        bytes32 prefixedHash = keccak256("\x19Ethereum Signed Message:\n", uint2str(_msgHex.length), _msgHex);
        address signer = ecrecover(prefixedHash, _v, _r, _s);
        return signer;
    }

    function uint2str(uint i) internal pure returns (string){
        if (i == 0) return "0";
        uint j = i;
        uint length;
        while (j != 0){
            length++;
            j /= 10;
        }
        bytes memory bstr = new bytes(length);
        uint k = length - 1;
        while (i != 0){
            bstr[k--] = byte(48 + i % 10);
            i /= 10;
        }
        return string(bstr);
    }

}