pragma solidity ^0.5.7;

contract Identity {
    mapping(address => string) private _names;

    /**
     * Handy function to associate a short name with the account.
     */
    function iAm(string memory shortName) public {
        _names[msg.sender] = shortName;
    }

    /**
     * Handy function to confirm address of the current account.
     */
    function whereAmI() public view returns (address yourAddress) {
        address myself = msg.sender;
        return myself;
    }

    /**
     * Handy function to confirm short name of the current account.
     */
    function whoAmI() public view returns (string memory yourName) {
        return (_names[msg.sender]);
    }
}


pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}


pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}


pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "Insufficient funds");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b);
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}


pragma solidity ^0.5.0;


/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20Mintable}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0));

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal {
        require(account != address(0));

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal {
        require(owner != address(0));
        require(spender != address(0));

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }
}


pragma solidity ^0.5.0;


/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev See {ERC20-_burnFrom}.
     */
    function burnFrom(address account, uint256 amount) public {
        _burnFrom(account, amount);
    }
}


pragma solidity ^0.5.0;


/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
}


pragma solidity ^0.5.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}


pragma solidity ^0.5.0;

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev Give an account access to this role.
     */
    function add(Role storage role, address account) internal {
        require(!has(role, account));
        role.bearer[account] = true;
    }

    /**
     * @dev Remove an account's access to this role.
     */
    function remove(Role storage role, address account) internal {
        require(has(role, account));
        role.bearer[account] = false;
    }

    /**
     * @dev Check if an account has this role.
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}


pragma solidity ^0.5.7;


/**
 * @dev This role allows the contract to be paused, so that in case something goes horribly wrong
 * during an ICO, the owner/administrator has an ability to suspend all transactions while things
 * are sorted out.
 *
 * NOTE: We have implemented a role model only the contract owner can assign/un-assign roles.
 * This is necessary to support enterprise software, which requires a permissions model in which
 * roles can be owner-administered, in contrast to a blockchain community approach in which
 * permissions can be self-administered. Therefore, this implementation replaces the self-service
 * "renounce" approach with one where only the owner is allowed to makes role changes.
 *
 * Owner is not allowed to renounce ownership, lest the contract go without administration. But
 * it is ok for owner to shed initially granted roles by removing role from self.
 */
contract PauserRole is Ownable {
    using Roles for Roles.Role;

    event PauserAdded(address indexed account);
    event PauserRemoved(address indexed account);

    Roles.Role private _pausers;

    constructor () internal {
        _addPauser(msg.sender);
    }

    modifier onlyPauser() {
        require(isPauser(msg.sender), "onlyPauser");
        _;
    }

    function isPauser(address account) public view returns (bool) {
        return _pausers.has(account);
    }

    function addPauser(address account) public onlyOwner {
        _addPauser(account);
    }

    function removePauser(address account) public onlyOwner {
        _removePauser(account);
    }

    function _addPauser(address account) private {
        require(account != address(0));
        _pausers.add(account);
        emit PauserAdded(account);
    }

    function _removePauser(address account) private {
        require(account != address(0));
        _pausers.remove(account);
        emit PauserRemoved(account);
    }


    // =========================================================================
    // === Overridden ERC20 functionality
    // =========================================================================

    /**
     * Ensure there is no way for the contract to end up with no owner. That would inadvertently result in
     * pauser administration becoming impossible. We override this to always disallow it.
     */
    function renounceOwnership() public onlyOwner {
        require(false, "forbidden");
    }

    /**
     * @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) public onlyOwner {
        _removePauser(msg.sender);
        super.transferOwnership(newOwner);
        _addPauser(newOwner);
    }
}


pragma solidity ^0.5.0;


/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract Pausable is Context, PauserRole {
    /**
     * @dev Emitted when the pause is triggered by a pauser (`account`).
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by a pauser (`account`).
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state. Assigns the Pauser role
     * to the deployer.
     */
    constructor () internal {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     */
    modifier whenNotPaused() {
        require(!_paused);
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     */
    modifier whenPaused() {
        require(_paused);
        _;
    }

    /**
     * @dev Called by a pauser to pause, triggers stopped state.
     */
    function pause() public onlyPauser whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Called by a pauser to unpause, returns to normal state.
     */
    function unpause() public onlyPauser whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}


pragma solidity ^0.5.0;


/**
 * @title Pausable token
 * @dev ERC20 with pausable transfers and allowances.
 *
 * Useful if you want to stop trades until the end of a crowdsale, or have
 * an emergency switch for freezing all token transfers in the event of a large
 * bug.
 */
contract ERC20Pausable is ERC20, Pausable {
    function transfer(address to, uint256 value) public whenNotPaused returns (bool) {
        return super.transfer(to, value);
    }

    function transferFrom(address from, address to, uint256 value) public whenNotPaused returns (bool) {
        return super.transferFrom(from, to, value);
    }

    function approve(address spender, uint256 value) public whenNotPaused returns (bool) {
        return super.approve(spender, value);
    }

    function increaseAllowance(address spender, uint256 addedValue) public whenNotPaused returns (bool) {
        return super.increaseAllowance(spender, addedValue);
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public whenNotPaused returns (bool) {
        return super.decreaseAllowance(spender, subtractedValue);
    }
}


pragma solidity ^0.5.7;


contract VerifiedAccount is ERC20, Ownable {

    mapping(address => bool) private _isRegistered;

    constructor () internal {
        // The smart contract starts off registering itself, since address is known.
        registerAccount();
    }

    event AccountRegistered(address indexed account);

    /**
     * This registers the calling wallet address as a known address. Operations that transfer responsibility
     * may require the target account to be a registered account, to protect the system from getting into a
     * state where administration or a large amount of funds can become forever inaccessible.
     */
    function registerAccount() public returns (bool ok) {
        _isRegistered[msg.sender] = true;
        emit AccountRegistered(msg.sender);
        return true;
    }

    function isRegistered(address account) public view returns (bool ok) {
        return _isRegistered[account];
    }

    function _accountExists(address account) internal view returns (bool exists) {
        return account == msg.sender || _isRegistered[account];
    }

    modifier onlyExistingAccount(address account) {
        require(_accountExists(account), "account not registered");
        _;
    }


    // =========================================================================
    // === Safe ERC20 methods
    // =========================================================================

    function safeTransfer(address to, uint256 value) public onlyExistingAccount(to) returns (bool ok) {
        transfer(to, value);
        return true;
    }

    function safeApprove(address spender, uint256 value) public onlyExistingAccount(spender) returns (bool ok) {
        approve(spender, value);
        return true;
    }

    function safeTransferFrom(address from, address to, uint256 value) public onlyExistingAccount(to) returns (bool ok) {
        transferFrom(from, to, value);
        return true;
    }


    // =========================================================================
    // === Safe ownership transfer
    // =========================================================================

    /**
     * @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) public onlyExistingAccount(newOwner) onlyOwner {
        super.transferOwnership(newOwner);
    }
}


pragma solidity ^0.5.7;


/**
 * @dev GrantorRole trait
 *
 * This adds support for a role that allows creation of vesting token grants, allocated from the
 * role holder's wallet.
 *
 * NOTE: We have implemented a role model only the contract owner can assign/un-assign roles.
 * This is necessary to support enterprise software, which requires a permissions model in which
 * roles can be owner-administered, in contrast to a blockchain community approach in which
 * permissions can be self-administered. Therefore, this implementation replaces the self-service
 * "renounce" approach with one where only the owner is allowed to makes role changes.
 *
 * Owner is not allowed to renounce ownership, lest the contract go without administration. But
 * it is ok for owner to shed initially granted roles by removing role from self.
 */
contract GrantorRole is Ownable {
    bool private constant OWNER_UNIFORM_GRANTOR_FLAG = false;

    using Roles for Roles.Role;

    event GrantorAdded(address indexed account);
    event GrantorRemoved(address indexed account);

    Roles.Role private _grantors;
    mapping(address => bool) private _isUniformGrantor;

    constructor () internal {
        _addGrantor(msg.sender, OWNER_UNIFORM_GRANTOR_FLAG);
    }

    modifier onlyGrantor() {
        require(isGrantor(msg.sender), "onlyGrantor");
        _;
    }

    modifier onlyGrantorOrSelf(address account) {
        require(isGrantor(msg.sender) || msg.sender == account, "onlyGrantorOrSelf");
        _;
    }

    function isGrantor(address account) public view returns (bool) {
        return _grantors.has(account);
    }

    function addGrantor(address account, bool isUniformGrantor) public onlyOwner {
        _addGrantor(account, isUniformGrantor);
    }

    function removeGrantor(address account) public onlyOwner {
        _removeGrantor(account);
    }

    function _addGrantor(address account, bool isUniformGrantor) private {
        require(account != address(0));
        _grantors.add(account);
        _isUniformGrantor[account] = isUniformGrantor;
        emit GrantorAdded(account);
    }

    function _removeGrantor(address account) private {
        require(account != address(0));
        _grantors.remove(account);
        emit GrantorRemoved(account);
    }

    function isUniformGrantor(address account) public view returns (bool) {
        return isGrantor(account) && _isUniformGrantor[account];
    }

    modifier onlyUniformGrantor() {
        require(isUniformGrantor(msg.sender), "onlyUniformGrantor");
        // Only grantor role can do this.
        _;
    }


    // =========================================================================
    // === Overridden ERC20 functionality
    // =========================================================================

    /**
     * Ensure there is no way for the contract to end up with no owner. That would inadvertently result in
     * token grant administration becoming impossible. We override this to always disallow it.
     */
    function renounceOwnership() public onlyOwner {
        require(false, "forbidden");
    }

    /**
     * @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) public onlyOwner {
        _removeGrantor(msg.sender);
        super.transferOwnership(newOwner);
        _addGrantor(newOwner, OWNER_UNIFORM_GRANTOR_FLAG);
    }
}


pragma solidity ^0.5.7;


interface IERC20Vestable {
    function getIntrinsicVestingSchedule(address grantHolder)
    external
    view
    returns (
        uint32 cliffDuration,
        uint32 vestDuration,
        uint32 vestIntervalDays
    );

    function grantVestingTokens(
        address beneficiary,
        uint256 totalAmount,
        uint256 vestingAmount,
        uint32 startDay,
        uint32 duration,
        uint32 cliffDuration,
        uint32 interval,
        bool isRevocable
    ) external returns (bool ok);

    function today() external view returns (uint32 dayNumber);

    function vestingForAccountAsOf(
        address grantHolder,
        uint32 onDayOrToday
    )
    external
    view
    returns (
        uint256 amountVested,
        uint256 amountNotVested,
        uint256 amountOfGrant,
        uint32 vestStartDay,
        uint32 cliffDuration,
        uint32 vestDuration,
        uint32 vestIntervalDays,
        bool isActive,
        bool wasRevoked
    );

    function vestingAsOf(uint32 onDayOrToday) external view returns (
        uint256 amountVested,
        uint256 amountNotVested,
        uint256 amountOfGrant,
        uint32 vestStartDay,
        uint32 cliffDuration,
        uint32 vestDuration,
        uint32 vestIntervalDays,
        bool isActive,
        bool wasRevoked
    );

    function revokeGrant(address grantHolder, uint32 onDay) external returns (bool);


    event VestingScheduleCreated(
        address indexed vestingLocation,
        uint32 cliffDuration, uint32 indexed duration, uint32 interval,
        bool indexed isRevocable);

    event VestingTokensGranted(
        address indexed beneficiary,
        uint256 indexed vestingAmount,
        uint32 startDay,
        address vestingLocation,
        address indexed grantor);

    event GrantRevoked(address indexed grantHolder, uint32 indexed onDay);
}


pragma solidity ^0.5.7;


/**
 * @title Contract for grantable ERC20 token vesting schedules
 *
 * @notice Adds to an ERC20 support for grantor wallets, which are able to grant vesting tokens to
 *   beneficiary wallets, following per-wallet custom vesting schedules.
 *
 * @dev Contract which gives subclass contracts the ability to act as a pool of funds for allocating
 *   tokens to any number of other addresses. Token grants support the ability to vest over time in
 *   accordance a predefined vesting schedule. A given wallet can receive no more than one token grant.
 *
 *   Tokens are transferred from the pool to the recipient at the time of grant, but the recipient
 *   will only able to transfer tokens out of their wallet after they have vested. Transfers of non-
 *   vested tokens are prevented.
 *
 *   Two types of toke grants are supported:
 *   - Irrevocable grants, intended for use in cases when vesting tokens have been issued in exchange
 *     for value, such as with tokens that have been purchased in an ICO.
 *   - Revocable grants, intended for use in cases when vesting tokens have been gifted to the holder,
 *     such as with employee grants that are given as compensation.
 */
contract ERC20Vestable is ERC20, VerifiedAccount, GrantorRole, IERC20Vestable {
    using SafeMath for uint256;

    // Date-related constants for sanity-checking dates to reject obvious erroneous inputs
    // and conversions from seconds to days and years that are more or less leap year-aware.
    uint32 private constant THOUSAND_YEARS_DAYS = 365243;                   /* See https://www.timeanddate.com/date/durationresult.html?m1=1&d1=1&y1=2000&m2=1&d2=1&y2=3000 */
    uint32 private constant TEN_YEARS_DAYS = THOUSAND_YEARS_DAYS / 100;     /* Includes leap years (though it doesn't really matter) */
    uint32 private constant SECONDS_PER_DAY = 24 * 60 * 60;                 /* 86400 seconds in a day */
    uint32 private constant JAN_1_2000_SECONDS = 946684800;                 /* Saturday, January 1, 2000 0:00:00 (GMT) (see https://www.epochconverter.com/) */
    uint32 private constant JAN_1_2000_DAYS = JAN_1_2000_SECONDS / SECONDS_PER_DAY;
    uint32 private constant JAN_1_3000_DAYS = JAN_1_2000_DAYS + THOUSAND_YEARS_DAYS;

    struct vestingSchedule {
        bool isValid;               /* true if an entry exists and is valid */
        bool isRevocable;           /* true if the vesting option is revocable (a gift), false if irrevocable (purchased) */
        uint32 cliffDuration;       /* Duration of the cliff, with respect to the grant start day, in days. */
        uint32 duration;            /* Duration of the vesting schedule, with respect to the grant start day, in days. */
        uint32 interval;            /* Duration in days of the vesting interval. */
    }

    struct tokenGrant {
        bool isActive;              /* true if this vesting entry is active and in-effect entry. */
        bool wasRevoked;            /* true if this vesting schedule was revoked. */
        uint32 startDay;            /* Start day of the grant, in days since the UNIX epoch (start of day). */
        uint256 amount;             /* Total number of tokens that vest. */
        address vestingLocation;    /* Address of wallet that is holding the vesting schedule. */
        address grantor;            /* Grantor that made the grant */
    }

    mapping(address => vestingSchedule) private _vestingSchedules;
    mapping(address => tokenGrant) private _tokenGrants;


    // =========================================================================
    // === Methods for administratively creating a vesting schedule for an account.
    // =========================================================================

    /**
     * @dev This one-time operation permanently establishes a vesting schedule in the given account.
     *
     * For standard grants, this establishes the vesting schedule in the beneficiary's account.
     * For uniform grants, this establishes the vesting schedule in the linked grantor's account.
     *
     * @param vestingLocation = Account into which to store the vesting schedule. Can be the account
     *   of the beneficiary (for one-off grants) or the account of the grantor (for uniform grants
     *   made from grant pools).
     * @param cliffDuration = Duration of the cliff, with respect to the grant start day, in days.
     * @param duration = Duration of the vesting schedule, with respect to the grant start day, in days.
     * @param interval = Number of days between vesting increases.
     * @param isRevocable = True if the grant can be revoked (i.e. was a gift) or false if it cannot
     *   be revoked (i.e. tokens were purchased).
     */
    function _setVestingSchedule(
        address vestingLocation,
        uint32 cliffDuration, uint32 duration, uint32 interval,
        bool isRevocable) internal returns (bool ok) {

        // Check for a valid vesting schedule given (disallow absurd values to reject likely bad input).
        require(
            duration > 0 && duration <= TEN_YEARS_DAYS
            && cliffDuration < duration
            && interval >= 1,
            "invalid vesting schedule"
        );

        // Make sure the duration values are in harmony with interval (both should be an exact multiple of interval).
        require(
            duration % interval == 0 && cliffDuration % interval == 0,
            "invalid cliff/duration for interval"
        );

        // Create and populate a vesting schedule.
        _vestingSchedules[vestingLocation] = vestingSchedule(
            true/*isValid*/,
            isRevocable,
            cliffDuration, duration, interval
        );

        // Emit the event and return success.
        emit VestingScheduleCreated(
            vestingLocation,
            cliffDuration, duration, interval,
            isRevocable);
        return true;
    }

    function _hasVestingSchedule(address account) internal view returns (bool ok) {
        return _vestingSchedules[account].isValid;
    }

    /**
     * @dev returns all information about the vesting schedule directly associated with the given
     * account. This can be used to double check that a uniform grantor has been set up with a
     * correct vesting schedule. Also, recipients of standard (non-uniform) grants can use this.
     * This method is only callable by the account holder or a grantor, so this is mainly intended
     * for administrative use.
     *
     * Holders of uniform grants must use vestingAsOf() to view their vesting schedule, as it is
     * stored in the grantor account.
     *
     * @param grantHolder = The address to do this for.
     *   the special value 0 to indicate today.
     * @return = A tuple with the following values:
     *   vestDuration = grant duration in days.
     *   cliffDuration = duration of the cliff.
     *   vestIntervalDays = number of days between vesting periods.
     */
    function getIntrinsicVestingSchedule(address grantHolder)
    public
    view
    onlyGrantorOrSelf(grantHolder)
    returns (
        uint32 vestDuration,
        uint32 cliffDuration,
        uint32 vestIntervalDays
    )
    {
        return (
        _vestingSchedules[grantHolder].duration,
        _vestingSchedules[grantHolder].cliffDuration,
        _vestingSchedules[grantHolder].interval
        );
    }


    // =========================================================================
    // === Token grants (general-purpose)
    // === Methods to be used for administratively creating one-off token grants with vesting schedules.
    // =========================================================================

    /**
     * @dev Immediately grants tokens to an account, referencing a vesting schedule which may be
     * stored in the same account (individual/one-off) or in a different account (shared/uniform).
     *
     * @param beneficiary = Address to which tokens will be granted.
     * @param totalAmount = Total number of tokens to deposit into the account.
     * @param vestingAmount = Out of totalAmount, the number of tokens subject to vesting.
     * @param startDay = Start day of the grant's vesting schedule, in days since the UNIX epoch
     *   (start of day). The startDay may be given as a date in the future or in the past, going as far
     *   back as year 2000.
     * @param vestingLocation = Account where the vesting schedule is held (must already exist).
     * @param grantor = Account which performed the grant. Also the account from where the granted
     *   funds will be withdrawn.
     */
    function _grantVestingTokens(
        address beneficiary,
        uint256 totalAmount,
        uint256 vestingAmount,
        uint32 startDay,
        address vestingLocation,
        address grantor
    )
    internal returns (bool ok)
    {
        // Make sure no prior grant is in effect.
        require(!_tokenGrants[beneficiary].isActive, "grant already exists");

        // Check for valid vestingAmount
        require(
            vestingAmount <= totalAmount && vestingAmount > 0
            && startDay >= JAN_1_2000_DAYS && startDay < JAN_1_3000_DAYS,
            "invalid vesting params");

        // Make sure the vesting schedule we are about to use is valid.
        require(_hasVestingSchedule(vestingLocation), "no such vesting schedule");

        // Transfer the total number of tokens from grantor into the account's holdings.
        _transfer(grantor, beneficiary, totalAmount);
        /* Emits a Transfer event. */

        // Create and populate a token grant, referencing vesting schedule.
        _tokenGrants[beneficiary] = tokenGrant(
            true/*isActive*/,
            false/*wasRevoked*/,
            startDay,
            vestingAmount,
            vestingLocation, /* The wallet address where the vesting schedule is kept. */
            grantor             /* The account that performed the grant (where revoked funds would be sent) */
        );

        // Emit the event and return success.
        emit VestingTokensGranted(beneficiary, vestingAmount, startDay, vestingLocation, grantor);
        return true;
    }

    /**
     * @dev Immediately grants tokens to an address, including a portion that will vest over time
     * according to a set vesting schedule. The overall duration and cliff duration of the grant must
     * be an even multiple of the vesting interval.
     *
     * @param beneficiary = Address to which tokens will be granted.
     * @param totalAmount = Total number of tokens to deposit into the account.
     * @param vestingAmount = Out of totalAmount, the number of tokens subject to vesting.
     * @param startDay = Start day of the grant's vesting schedule, in days since the UNIX epoch
     *   (start of day). The startDay may be given as a date in the future or in the past, going as far
     *   back as year 2000.
     * @param duration = Duration of the vesting schedule, with respect to the grant start day, in days.
     * @param cliffDuration = Duration of the cliff, with respect to the grant start day, in days.
     * @param interval = Number of days between vesting increases.
     * @param isRevocable = True if the grant can be revoked (i.e. was a gift) or false if it cannot
     *   be revoked (i.e. tokens were purchased).
     */
    function grantVestingTokens(
        address beneficiary,
        uint256 totalAmount,
        uint256 vestingAmount,
        uint32 startDay,
        uint32 duration,
        uint32 cliffDuration,
        uint32 interval,
        bool isRevocable
    ) public onlyGrantor returns (bool ok) {
        // Make sure no prior vesting schedule has been set.
        require(!_tokenGrants[beneficiary].isActive, "grant already exists");

        // The vesting schedule is unique to this wallet and so will be stored here,
        _setVestingSchedule(beneficiary, cliffDuration, duration, interval, isRevocable);

        // Issue grantor tokens to the beneficiary, using beneficiary's own vesting schedule.
        _grantVestingTokens(beneficiary, totalAmount, vestingAmount, startDay, beneficiary, msg.sender);

        return true;
    }

    /**
     * @dev This variant only grants tokens if the beneficiary account has previously self-registered.
     */
    function safeGrantVestingTokens(
        address beneficiary, uint256 totalAmount, uint256 vestingAmount,
        uint32 startDay, uint32 duration, uint32 cliffDuration, uint32 interval,
        bool isRevocable) public onlyGrantor onlyExistingAccount(beneficiary) returns (bool ok) {

        return grantVestingTokens(
            beneficiary, totalAmount, vestingAmount,
            startDay, duration, cliffDuration, interval,
            isRevocable);
    }


    // =========================================================================
    // === Check vesting.
    // =========================================================================

    /**
     * @dev returns the day number of the current day, in days since the UNIX epoch.
     */
    function today() public view returns (uint32 dayNumber) {
        return uint32(block.timestamp / SECONDS_PER_DAY);
    }

    function _effectiveDay(uint32 onDayOrToday) internal view returns (uint32 dayNumber) {
        return onDayOrToday == 0 ? today() : onDayOrToday;
    }

    /**
     * @dev Determines the amount of tokens that have not vested in the given account.
     *
     * The math is: not vested amount = vesting amount * (end date - on date)/(end date - start date)
     *
     * @param grantHolder = The account to check.
     * @param onDayOrToday = The day to check for, in days since the UNIX epoch. Can pass
     *   the special value 0 to indicate today.
     */
    function _getNotVestedAmount(address grantHolder, uint32 onDayOrToday) internal view returns (uint256 amountNotVested) {
        tokenGrant storage grant = _tokenGrants[grantHolder];
        vestingSchedule storage vesting = _vestingSchedules[grant.vestingLocation];
        uint32 onDay = _effectiveDay(onDayOrToday);

        // If there's no schedule, or before the vesting cliff, then the full amount is not vested.
        if (!grant.isActive || onDay < grant.startDay + vesting.cliffDuration)
        {
            // None are vested (all are not vested)
            return grant.amount;
        }
        // If after end of vesting, then the not vested amount is zero (all are vested).
        else if (onDay >= grant.startDay + vesting.duration)
        {
            // All are vested (none are not vested)
            return uint256(0);
        }
        // Otherwise a fractional amount is vested.
        else
        {
            // Compute the exact number of days vested.
            uint32 daysVested = onDay - grant.startDay;
            // Adjust result rounding down to take into consideration the interval.
            uint32 effectiveDaysVested = (daysVested / vesting.interval) * vesting.interval;

            // Compute the fraction vested from schedule using 224.32 fixed point math for date range ratio.
            // Note: This is safe in 256-bit math because max value of X billion tokens = X*10^27 wei, and
            // typical token amounts can fit into 90 bits. Scaling using a 32 bits value results in only 125
            // bits before reducing back to 90 bits by dividing. There is plenty of room left, even for token
            // amounts many orders of magnitude greater than mere billions.
            uint256 vested = grant.amount.mul(effectiveDaysVested).div(vesting.duration);
            return grant.amount.sub(vested);
        }
    }

    /**
     * @dev Computes the amount of funds in the given account which are available for use as of
     * the given day. If there's no vesting schedule then 0 tokens are considered to be vested and
     * this just returns the full account balance.
     *
     * The math is: available amount = total funds - notVestedAmount.
     *
     * @param grantHolder = The account to check.
     * @param onDay = The day to check for, in days since the UNIX epoch.
     */
    function _getAvailableAmount(address grantHolder, uint32 onDay) internal view returns (uint256 amountAvailable) {
        uint256 totalTokens = balanceOf(grantHolder);
        uint256 vested = totalTokens.sub(_getNotVestedAmount(grantHolder, onDay));
        return vested;
    }

    /**
     * @dev returns all information about the grant's vesting as of the given day
     * for the given account. Only callable by the account holder or a grantor, so
     * this is mainly intended for administrative use.
     *
     * @param grantHolder = The address to do this for.
     * @param onDayOrToday = The day to check for, in days since the UNIX epoch. Can pass
     *   the special value 0 to indicate today.
     * @return = A tuple with the following values:
     *   amountVested = the amount out of vestingAmount that is vested
     *   amountNotVested = the amount that is vested (equal to vestingAmount - vestedAmount)
     *   amountOfGrant = the amount of tokens subject to vesting.
     *   vestStartDay = starting day of the grant (in days since the UNIX epoch).
     *   vestDuration = grant duration in days.
     *   cliffDuration = duration of the cliff.
     *   vestIntervalDays = number of days between vesting periods.
     *   isActive = true if the vesting schedule is currently active.
     *   wasRevoked = true if the vesting schedule was revoked.
     */
    function vestingForAccountAsOf(
        address grantHolder,
        uint32 onDayOrToday
    )
    public
    view
    onlyGrantorOrSelf(grantHolder)
    returns (
        uint256 amountVested,
        uint256 amountNotVested,
        uint256 amountOfGrant,
        uint32 vestStartDay,
        uint32 vestDuration,
        uint32 cliffDuration,
        uint32 vestIntervalDays,
        bool isActive,
        bool wasRevoked
    )
    {
        tokenGrant storage grant = _tokenGrants[grantHolder];
        vestingSchedule storage vesting = _vestingSchedules[grant.vestingLocation];
        uint256 notVestedAmount = _getNotVestedAmount(grantHolder, onDayOrToday);
        uint256 grantAmount = grant.amount;

        return (
        grantAmount.sub(notVestedAmount),
        notVestedAmount,
        grantAmount,
        grant.startDay,
        vesting.duration,
        vesting.cliffDuration,
        vesting.interval,
        grant.isActive,
        grant.wasRevoked
        );
    }

    /**
     * @dev returns all information about the grant's vesting as of the given day
     * for the current account, to be called by the account holder.
     *
     * @param onDayOrToday = The day to check for, in days since the UNIX epoch. Can pass
     *   the special value 0 to indicate today.
     * @return = A tuple with the following values:
     *   amountVested = the amount out of vestingAmount that is vested
     *   amountNotVested = the amount that is vested (equal to vestingAmount - vestedAmount)
     *   amountOfGrant = the amount of tokens subject to vesting.
     *   vestStartDay = starting day of the grant (in days since the UNIX epoch).
     *   cliffDuration = duration of the cliff.
     *   vestDuration = grant duration in days.
     *   vestIntervalDays = number of days between vesting periods.
     *   isActive = true if the vesting schedule is currently active.
     *   wasRevoked = true if the vesting schedule was revoked.
     */
    function vestingAsOf(uint32 onDayOrToday) public view returns (
        uint256 amountVested,
        uint256 amountNotVested,
        uint256 amountOfGrant,
        uint32 vestStartDay,
        uint32 vestDuration,
        uint32 cliffDuration,
        uint32 vestIntervalDays,
        bool isActive,
        bool wasRevoked
    )
    {
        return vestingForAccountAsOf(msg.sender, onDayOrToday);
    }

    /**
     * @dev returns true if the account has sufficient funds available to cover the given amount,
     *   including consideration for vesting tokens.
     *
     * @param account = The account to check.
     * @param amount = The required amount of vested funds.
     * @param onDay = The day to check for, in days since the UNIX epoch.
     */
    function _fundsAreAvailableOn(address account, uint256 amount, uint32 onDay) internal view returns (bool ok) {
        return (amount <= _getAvailableAmount(account, onDay));
    }

    /**
     * @dev Modifier to make a function callable only when the amount is sufficiently vested right now.
     *
     * @param account = The account to check.
     * @param amount = The required amount of vested funds.
     */
    modifier onlyIfFundsAvailableNow(address account, uint256 amount) {
        // Distinguish insufficient overall balance from insufficient vested funds balance in failure msg.
        require(_fundsAreAvailableOn(account, amount, today()),
            balanceOf(account) < amount ? "insufficient funds" : "insufficient vested funds");
        _;
    }


    // =========================================================================
    // === Grant revocation
    // =========================================================================

    /**
     * @dev If the account has a revocable grant, this forces the grant to end based on computing
     * the amount vested up to the given date. All tokens that would no longer vest are returned
     * to the account of the original grantor.
     *
     * @param grantHolder = Address to which tokens will be granted.
     * @param onDay = The date upon which the vesting schedule will be effectively terminated,
     *   in days since the UNIX epoch (start of day).
     */
    function revokeGrant(address grantHolder, uint32 onDay) public onlyGrantor returns (bool ok) {
        tokenGrant storage grant = _tokenGrants[grantHolder];
        vestingSchedule storage vesting = _vestingSchedules[grant.vestingLocation];
        uint256 notVestedAmount;

        // Make sure grantor can only revoke from own pool.
        require(msg.sender == owner() || msg.sender == grant.grantor, "not allowed");
        // Make sure a vesting schedule has previously been set.
        require(grant.isActive, "no active grant");
        // Make sure it's revocable.
        require(vesting.isRevocable, "irrevocable");
        // Fail on likely erroneous input.
        require(onDay <= grant.startDay + vesting.duration, "no effect");
        // Don"t let grantor revoke anf portion of vested amount.
        require(onDay >= today(), "cannot revoke vested holdings");

        notVestedAmount = _getNotVestedAmount(grantHolder, onDay);

        // Use ERC20 _approve() to forcibly approve grantor to take back not-vested tokens from grantHolder.
        _approve(grantHolder, grant.grantor, notVestedAmount);
        /* Emits an Approval Event. */
        transferFrom(grantHolder, grant.grantor, notVestedAmount);
        /* Emits a Transfer and an Approval Event. */

        // Kill the grant by updating wasRevoked and isActive.
        _tokenGrants[grantHolder].wasRevoked = true;
        _tokenGrants[grantHolder].isActive = false;

        emit GrantRevoked(grantHolder, onDay);
        /* Emits the GrantRevoked event. */
        return true;
    }


    // =========================================================================
    // === Overridden ERC20 functionality
    // =========================================================================

    /**
     * @dev Methods transfer() and approve() require an additional available funds check to
     * prevent spending held but non-vested tokens. Note that transferFrom() does NOT have this
     * additional check because approved funds come from an already set-aside allowance, not from the wallet.
     */
    function transfer(address to, uint256 value) public onlyIfFundsAvailableNow(msg.sender, value) returns (bool ok) {
        return super.transfer(to, value);
    }

    /**
     * @dev Additional available funds check to prevent spending held but non-vested tokens.
     */
    function approve(address spender, uint256 value) public onlyIfFundsAvailableNow(msg.sender, value) returns (bool ok) {
        return super.approve(spender, value);
    }
}


pragma solidity ^0.5.7;


/**
 * @title Contract for uniform granting of vesting tokens
 *
 * @notice Adds methods for programmatic creation of uniform or standard token vesting grants.
 *
 * @dev This is primarily for use by exchanges and scripted internal employee incentive grant creation.
 */
contract UniformTokenGrantor is ERC20Vestable {

    struct restrictions {
        bool isValid;
        uint32 minStartDay;        /* The smallest value for startDay allowed in grant creation. */
        uint32 maxStartDay;        /* The maximum value for startDay allowed in grant creation. */
        uint32 expirationDay;       /* The last day this grantor may make grants. */
    }

    mapping(address => restrictions) private _restrictions;


    // =========================================================================
    // === Uniform token grant setup
    // === Methods used by owner to set up uniform grants on restricted grantor
    // =========================================================================

    event GrantorRestrictionsSet(
        address indexed grantor,
        uint32 minStartDay,
        uint32 maxStartDay,
        uint32 expirationDay);

    /**
     * @dev Lets owner set or change existing specific restrictions. Restrictions must be established
     * before the grantor will be allowed to issue grants.
     *
     * All date values are expressed as number of days since the UNIX epoch. Note that the inputs are
     * themselves not very thoroughly restricted. However, this method can be called more than once
     * if incorrect values need to be changed, or to extend a grantor's expiration date.
     *
     * @param grantor = Address which will receive the uniform grantable vesting schedule.
     * @param minStartDay = The smallest value for startDay allowed in grant creation.
     * @param maxStartDay = The maximum value for startDay allowed in grant creation.
     * @param expirationDay = The last day this grantor may make grants.
     */
    function setRestrictions(
        address grantor,
        uint32 minStartDay,
        uint32 maxStartDay,
        uint32 expirationDay
    )
    public
    onlyOwner
    onlyExistingAccount(grantor)
    returns (bool ok)
    {
        require(
            isUniformGrantor(grantor)
         && maxStartDay > minStartDay
         && expirationDay > today(), "invalid params");

        // We allow owner to set or change existing specific restrictions.
        _restrictions[grantor] = restrictions(
            true/*isValid*/,
            minStartDay,
            maxStartDay,
            expirationDay
        );

        // Emit the event and return success.
        emit GrantorRestrictionsSet(grantor, minStartDay, maxStartDay, expirationDay);
        return true;
    }

    /**
     * @dev Lets owner permanently establish a vesting schedule for a restricted grantor to use when
     * creating uniform token grants. Grantee accounts forever refer to the grantor's account to look up
     * vesting, so this method can only be used once per grantor.
     *
     * @param grantor = Address which will receive the uniform grantable vesting schedule.
     * @param duration = Duration of the vesting schedule, with respect to the grant start day, in days.
     * @param cliffDuration = Duration of the cliff, with respect to the grant start day, in days.
     * @param interval = Number of days between vesting increases.
     * @param isRevocable = True if the grant can be revoked (i.e. was a gift) or false if it cannot
     *   be revoked (i.e. tokens were purchased).
     */
    function setGrantorVestingSchedule(
        address grantor,
        uint32 duration,
        uint32 cliffDuration,
        uint32 interval,
        bool isRevocable
    )
    public
    onlyOwner
    onlyExistingAccount(grantor)
    returns (bool ok)
    {
        // Only allow doing this to restricted grantor role account.
        require(isUniformGrantor(grantor), "uniform grantor only");
        // Make sure no prior vesting schedule has been set!
        require(!_hasVestingSchedule(grantor), "schedule already exists");

        // The vesting schedule is unique to this grantor wallet and so will be stored here to be
        // referenced by future grants. Emits VestingScheduleCreated event.
        _setVestingSchedule(grantor, cliffDuration, duration, interval, isRevocable);

        return true;
    }


    // =========================================================================
    // === Uniform token grants
    // === Methods to be used by exchanges to use for creating tokens.
    // =========================================================================

    function isUniformGrantorWithSchedule(address account) internal view returns (bool ok) {
        // Check for grantor that has a uniform vesting schedule already set.
        return isUniformGrantor(account) && _hasVestingSchedule(account);
    }

    modifier onlyUniformGrantorWithSchedule(address account) {
        require(isUniformGrantorWithSchedule(account), "grantor account not ready");
        _;
    }

    modifier whenGrantorRestrictionsMet(uint32 startDay) {
        restrictions storage restriction = _restrictions[msg.sender];
        require(restriction.isValid, "set restrictions first");

        require(
            startDay >= restriction.minStartDay
            && startDay < restriction.maxStartDay, "startDay too early");

        require(today() < restriction.expirationDay, "grantor expired");
        _;
    }

    /**
     * @dev Immediately grants tokens to an address, including a portion that will vest over time
     * according to the uniform vesting schedule already established in the grantor's account.
     *
     * @param beneficiary = Address to which tokens will be granted.
     * @param totalAmount = Total number of tokens to deposit into the account.
     * @param vestingAmount = Out of totalAmount, the number of tokens subject to vesting.
     * @param startDay = Start day of the grant's vesting schedule, in days since the UNIX epoch
     *   (start of day). The startDay may be given as a date in the future or in the past, going as far
     *   back as year 2000.
     */
    function grantUniformVestingTokens(
        address beneficiary,
        uint256 totalAmount,
        uint256 vestingAmount,
        uint32 startDay
    )
    public
    onlyUniformGrantorWithSchedule(msg.sender)
    whenGrantorRestrictionsMet(startDay)
    returns (bool ok)
    {
        // Issue grantor tokens to the beneficiary, using beneficiary's own vesting schedule.
        // Emits VestingTokensGranted event.
        return _grantVestingTokens(beneficiary, totalAmount, vestingAmount, startDay, msg.sender, msg.sender);
    }

    /**
     * @dev This variant only grants tokens if the beneficiary account has previously self-registered.
     */
    function safeGrantUniformVestingTokens(
        address beneficiary,
        uint256 totalAmount,
        uint256 vestingAmount,
        uint32 startDay
    )
    public
    onlyUniformGrantorWithSchedule(msg.sender)
    whenGrantorRestrictionsMet(startDay)
    onlyExistingAccount(beneficiary)
    returns (bool ok)
    {
        // Issue grantor tokens to the beneficiary, using beneficiary's own vesting schedule.
        // Emits VestingTokensGranted event.
        return _grantVestingTokens(beneficiary, totalAmount, vestingAmount, startDay, msg.sender, msg.sender);
    }
}


pragma solidity ^0.5.7;


/**
 * @dev An ERC20 implementation of the CXPcoin ecosystem token. All tokens are initially pre-assigned to
 * the creator, and can later be distributed freely using transfer transferFrom and other ERC20
 * functions.
 */
contract CxpCoin is Identity, ERC20, ERC20Pausable, ERC20Burnable, ERC20Detailed, UniformTokenGrantor {
    uint32 public constant VERSION = 8;

    uint8 private constant DECIMALS = 18;
    uint256 private constant TOKEN_WEI = 10 ** uint256(DECIMALS);

    uint256 private constant INITIAL_WHOLE_TOKENS = uint256(10 * (10 ** 9));
    uint256 private constant INITIAL_SUPPLY = uint256(INITIAL_WHOLE_TOKENS) * uint256(TOKEN_WEI);

    /**
     * @dev Constructor that gives msg.sender all of existing tokens.
     */
    constructor () ERC20Detailed("CXPcoin", "CXP", DECIMALS) public {
        // This is the only place where we ever mint tokens.
        _mint(msg.sender, INITIAL_SUPPLY);
    }

    event DepositReceived(address indexed from, uint256 value);

    /**
     * fallback function: collect any ether sent to us (whether we asked for it or not).
     */
    function() payable external {
        // Track where unexpected ETH came from so we can follow up later.
        emit DepositReceived(msg.sender, msg.value);
    }

    /**
     * @dev Allow only the owner to burn tokens from the owner's wallet, also decreasing the total
     * supply. There is no reason for a token holder to EVER call this method directly. It will be
     * used by the future CXPcoin ecosystem token contract to implement token redemption.
     */
    function burn(uint256 value) onlyIfFundsAvailableNow(msg.sender, value) public {
        // This is the only place where we ever burn tokens.
        _burn(msg.sender, value);
    }

    /**
     * @dev Allow pauser to kill the contract (which must already be paused), with enough restrictions
     * in place to ensure this could not happen by accident very easily. ETH is returned to owner wallet.
     */
    function kill() whenPaused onlyPauser public returns (bool itsDeadJim) {
        require(isPauser(msg.sender), "onlyPauser");
        address payable payableOwner = address(uint160(owner()));
        selfdestruct(payableOwner);
        return true;
    }
}