hodlers smart contract

hodlers.sol

pragma solidity ^0.4.18;

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    owner = msg.sender;
  }


  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }


  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner public {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  /**
  * @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}

contract Custodian is Ownable {

	using SafeMath for uint256;

	struct Allocation {
		uint256 amount;
		uint256 timestamp;
	}

	uint256 public constant FEE_FACTOR = 5;

	address public wallet;
	mapping(address => Allocation) allocations;

	// Triggered when the wallet has been updated
    event WalletUpdated(address _who, address _oldWallet, address _newWallet);
    // Triggered when a diposit has been created
    event DepositCreated(address _who, uint256 _amount, uint256 _timestamp);
    // Triggered when a diposit has been claimed
    event DepositClaimed(address _who, uint256 _amount, uint256 _timestamp);
    // Triggered when a diposit has been updated
    event DepositUpdated(address _who, uint256 _amount);

    function Custodian(address _wallet) public {
        require(_wallet != address(0));
        wallet = _wallet;
    }

	function hodl(uint256 _timestamp) payable external returns (bool) {
		uint256 _amount = msg.value;

		// The expiration date must be greater than the current time
		require(_timestamp > now);
		// The amount of ETH to deposit must be greater than 0
		require(_amount > 0);
		// A user can only have one active allocation
		Allocation storage allocation = allocations[msg.sender];
		require(allocation.amount == 0);

		// Create and adds the new allocation to the allocations mapping
		allocations[msg.sender] = Allocation(_amount, _timestamp);

		DepositCreated(msg.sender, _amount, _timestamp);

		return true;
	}

	/**
	* The user is charge with a fee 3,5% if claims deposit before the
	* deposit expiration date
	*/
	function withdraw() payable external returns (bool) {
		// A user must have an active allocation
		Allocation storage allocation = allocations[msg.sender];
		require(allocation.amount > 0);

		uint256 _fee = 0;
		uint256 _amountToTransfer = allocation.amount;

		// Calculates fee
		if (now < allocation.timestamp) {
			_fee = allocation.amount.mul(FEE_FACTOR).div(100);
			_amountToTransfer = _amountToTransfer.sub(_fee);
		}

		// Transfer ETH deposit to user
		msg.sender.transfer(_amountToTransfer);

		// Transfer ETH fee to wallet
		if (_fee > 0) {
			wallet.transfer(_fee);
		}

		DepositClaimed(msg.sender, _amountToTransfer, allocation.timestamp);

		// Delete the allocation
		delete allocations[msg.sender];

		return true;
	}

    function setWallet(address _newWallet) external onlyOwner returns (bool) {
        require(_newWallet != address(0));

        address _oldValue = wallet;
        wallet = _newWallet;

        WalletUpdated(msg.sender, _oldValue, wallet);

        return true;
    }
}