pragma solidity 0.5.17; /** * Source: https://raw.githubusercontent.com/simple-restricted-token/reference-implementation/master/contracts/token/ERC1404/ERC1404.sol * With ERC-20 APIs removed (will be implemented as a separate contract). * And adding authorizeTransfer. */ interface IWhitelist { /** * @notice Detects if a transfer will be reverted and if so returns an appropriate reference code * @param from Sending address * @param to Receiving address * @param value Amount of tokens being transferred * @return Code by which to reference message for rejection reasoning * @dev Overwrite with your custom transfer restriction logic */ function detectTransferRestriction( address from, address to, uint value ) external view returns (uint8); /** * @notice Returns a human-readable message for a given restriction code * @param restrictionCode Identifier for looking up a message * @return Text showing the restriction's reasoning * @dev Overwrite with your custom message and restrictionCode handling */ function messageForTransferRestriction(uint8 restrictionCode) external pure returns (string memory); /** * @notice Called by the DAT contract before a transfer occurs. * @dev This call will revert when the transfer is not authorized. * This is a mutable call to allow additional data to be recorded, * such as when the user aquired their tokens. */ function authorizeTransfer( address _from, address _to, uint _value, bool _isSell ) external; function activateWallet( address _wallet ) external; function deactivateWallet( address _wallet ) external; function walletActivated( address _wallet ) external returns(bool); } interface IERC20Detailed { /** * @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() external view returns (uint8); function name() external view returns (string memory); function symbol() external view returns (string memory); } /** * @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, "SafeMath: addition overflow"); 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, "SafeMath: subtraction overflow"); } /** * @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, "SafeMath: multiplication overflow"); 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, "SafeMath: division by zero"); } /** * @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, "SafeMath: modulo by zero"); } /** * @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; } } /** * @title Reduces the size of terms before multiplication, to avoid an overflow, and then * restores the proper size after division. * @notice This effectively allows us to overflow values in the numerator and/or denominator * of a fraction, so long as the end result does not overflow as well. * @dev Results may be off by 1 + 0.000001% for 2x1 calls and 2 + 0.00001% for 2x2 calls. * Do not use if your contract expects very small result values to be accurate. */ library BigDiv { using SafeMath for uint; /// @notice The max possible value uint private constant MAX_UINT = 2**256 - 1; /// @notice When multiplying 2 terms <= this value the result won't overflow uint private constant MAX_BEFORE_SQUARE = 2**128 - 1; /// @notice The max error target is off by 1 plus up to 0.000001% error /// for bigDiv2x1 and that `* 2` for bigDiv2x2 uint private constant MAX_ERROR = 100000000; /// @notice A larger error threshold to use when multiple rounding errors may apply uint private constant MAX_ERROR_BEFORE_DIV = MAX_ERROR * 2; /** * @notice Returns the approx result of `a * b / d` so long as the result is <= MAX_UINT * @param _numA the first numerator term * @param _numB the second numerator term * @param _den the denominator * @return the approx result with up to off by 1 + MAX_ERROR, rounding down if needed */ function bigDiv2x1( uint _numA, uint _numB, uint _den ) internal pure returns (uint) { if (_numA == 0 || _numB == 0) { // would div by 0 or underflow if we don't special case 0 return 0; } uint value; if (MAX_UINT / _numA >= _numB) { // a*b does not overflow, return exact math value = _numA * _numB; value /= _den; return value; } // Sort numerators uint numMax = _numB; uint numMin = _numA; if (_numA > _numB) { numMax = _numA; numMin = _numB; } value = numMax / _den; if (value > MAX_ERROR) { // _den is small enough to be MAX_ERROR or better w/o a factor value = value.mul(numMin); return value; } // formula = ((a / f) * b) / (d / f) // factor >= a / sqrt(MAX) * (b / sqrt(MAX)) uint factor = numMin - 1; factor /= MAX_BEFORE_SQUARE; factor += 1; uint temp = numMax - 1; temp /= MAX_BEFORE_SQUARE; temp += 1; if (MAX_UINT / factor >= temp) { factor *= temp; value = numMax / factor; if (value > MAX_ERROR_BEFORE_DIV) { value = value.mul(numMin); temp = _den - 1; temp /= factor; temp = temp.add(1); value /= temp; return value; } } // formula: (a / (d / f)) * (b / f) // factor: b / sqrt(MAX) factor = numMin - 1; factor /= MAX_BEFORE_SQUARE; factor += 1; value = numMin / factor; temp = _den - 1; temp /= factor; temp += 1; temp = numMax / temp; value = value.mul(temp); return value; } /** * @notice Returns the approx result of `a * b / d` so long as the result is <= MAX_UINT * @param _numA the first numerator term * @param _numB the second numerator term * @param _den the denominator * @return the approx result with up to off by 1 + MAX_ERROR, rounding down if needed * @dev roundUp is implemented by first rounding down and then adding the max error to the result */ function bigDiv2x1RoundUp( uint _numA, uint _numB, uint _den ) internal pure returns (uint) { // first get the rounded down result uint value = bigDiv2x1(_numA, _numB, _den); if (value == 0) { // when the value rounds down to 0, assume up to an off by 1 error return 1; } // round down has a max error of MAX_ERROR, add that to the result // for a round up error of <= MAX_ERROR uint temp = value - 1; temp /= MAX_ERROR; temp += 1; if (MAX_UINT - value < temp) { // value + error would overflow, return MAX return MAX_UINT; } value += temp; return value; } /** * @notice Returns the approx result of `a * b / (c * d)` so long as the result is <= MAX_UINT * @param _numA the first numerator term * @param _numB the second numerator term * @param _denA the first denominator term * @param _denB the second denominator term * @return the approx result with up to off by 2 + MAX_ERROR*10 error, rounding down if needed * @dev this uses bigDiv2x1 and adds additional rounding error so the max error of this * formula is larger */ function bigDiv2x2( uint _numA, uint _numB, uint _denA, uint _denB ) internal pure returns (uint) { if (MAX_UINT / _denA >= _denB) { // denA*denB does not overflow, use bigDiv2x1 instead return bigDiv2x1(_numA, _numB, _denA * _denB); } if (_numA == 0 || _numB == 0) { // would div by 0 or underflow if we don't special case 0 return 0; } // Sort denominators uint denMax = _denB; uint denMin = _denA; if (_denA > _denB) { denMax = _denA; denMin = _denB; } uint value; if (MAX_UINT / _numA >= _numB) { // a*b does not overflow, use `a / d / c` value = _numA * _numB; value /= denMin; value /= denMax; return value; } // `ab / cd` where both `ab` and `cd` would overflow // Sort numerators uint numMax = _numB; uint numMin = _numA; if (_numA > _numB) { numMax = _numA; numMin = _numB; } // formula = (a/d) * b / c uint temp = numMax / denMin; if (temp > MAX_ERROR_BEFORE_DIV) { return bigDiv2x1(temp, numMin, denMax); } // formula: ((a/f) * b) / d then either * f / c or / c * f // factor >= a / sqrt(MAX) * (b / sqrt(MAX)) uint factor = numMin - 1; factor /= MAX_BEFORE_SQUARE; factor += 1; temp = numMax - 1; temp /= MAX_BEFORE_SQUARE; temp += 1; if (MAX_UINT / factor >= temp) { factor *= temp; value = numMax / factor; if (value > MAX_ERROR_BEFORE_DIV) { value = value.mul(numMin); value /= denMin; if (value > 0 && MAX_UINT / value >= factor) { value *= factor; value /= denMax; return value; } } } // formula: (a/f) * b / ((c*d)/f) // factor >= c / sqrt(MAX) * (d / sqrt(MAX)) factor = denMin; factor /= MAX_BEFORE_SQUARE; temp = denMax; // + 1 here prevents overflow of factor*temp temp /= MAX_BEFORE_SQUARE + 1; factor *= temp; return bigDiv2x1(numMax / factor, numMin, MAX_UINT); } } /** * @title Calculates the square root of a given value. * @dev Results may be off by 1. */ library Sqrt { /// @notice The max possible value uint private constant MAX_UINT = 2**256 - 1; // Source: https://github.com/ethereum/dapp-bin/pull/50 function sqrt(uint x) internal pure returns (uint y) { if (x == 0) { return 0; } else if (x <= 3) { return 1; } else if (x == MAX_UINT) { // Without this we fail on x + 1 below return 2**128 - 1; } uint z = (x + 1) / 2; y = x; while (z < y) { y = z; z = (x / z + z) / 2; } } } /** * @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); } /** * @dev Collection of functions related to the address type */ library Address { /** * @dev Returns true if `account` is a contract. * * [IMPORTANT] * ==== * It is unsafe to assume that an address for which this function returns * false is an externally-owned account (EOA) and not a contract. * * Among others, `isContract` will return false for the following * types of addresses: * * - an externally-owned account * - a contract in construction * - an address where a contract will be created * - an address where a contract lived, but was destroyed * ==== */ function isContract(address account) internal view returns (bool) { // According to EIP-1052, 0x0 is the value returned for not-yet created accounts // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned // for accounts without code, i.e. `keccak256('')` bytes32 codehash; bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470; // solhint-disable-next-line no-inline-assembly assembly { codehash := extcodehash(account) } return (codehash != accountHash && codehash != 0x0); } /** * @dev Converts an `address` into `address payable`. Note that this is * simply a type cast: the actual underlying value is not changed. * * _Available since v2.4.0._ */ function toPayable(address account) internal pure returns (address payable) { return address(uint160(account)); } /** * @dev Replacement for Solidity's `transfer`: sends `amount` wei to * `recipient`, forwarding all available gas and reverting on errors. * * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost * of certain opcodes, possibly making contracts go over the 2300 gas limit * imposed by `transfer`, making them unable to receive funds via * `transfer`. {sendValue} removes this limitation. * * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more]. * * IMPORTANT: because control is transferred to `recipient`, care must be * taken to not create reentrancy vulnerabilities. Consider using * {ReentrancyGuard} or the * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern]. * * _Available since v2.4.0._ */ function sendValue(address payable recipient, uint256 amount) internal { require(address(this).balance >= amount, "Address: insufficient balance"); // solhint-disable-next-line avoid-call-value (bool success, ) = recipient.call.value(amount)(""); require(success, "Address: unable to send value, recipient may have reverted"); } } /** * @title SafeERC20 * @dev Wrappers around ERC20 operations that throw on failure (when the token * contract returns false). Tokens that return no value (and instead revert or * throw on failure) are also supported, non-reverting calls are assumed to be * successful. * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract, * which allows you to call the safe operations as `token.safeTransfer(...)`, etc. */ library SafeERC20 { using SafeMath for uint256; using Address for address; function safeTransfer(IERC20 token, address to, uint256 value) internal { callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value)); } function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal { callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value)); } function safeApprove(IERC20 token, address spender, uint256 value) internal { // safeApprove should only be called when setting an initial allowance, // or when resetting it to zero. To increase and decrease it, use // 'safeIncreaseAllowance' and 'safeDecreaseAllowance' // solhint-disable-next-line max-line-length require((value == 0) || (token.allowance(address(this), spender) == 0), "SafeERC20: approve from non-zero to non-zero allowance" ); callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value)); } function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).add(value); callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero"); callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } /** * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement * on the return value: the return value is optional (but if data is returned, it must not be false). * @param token The token targeted by the call. * @param data The call data (encoded using abi.encode or one of its variants). */ function callOptionalReturn(IERC20 token, bytes memory data) private { // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since // we're implementing it ourselves. // A Solidity high level call has three parts: // 1. The target address is checked to verify it contains contract code // 2. The call itself is made, and success asserted // 3. The return value is decoded, which in turn checks the size of the returned data. // solhint-disable-next-line max-line-length require(address(token).isContract(), "SafeERC20: call to non-contract"); // solhint-disable-next-line avoid-low-level-calls (bool success, bytes memory returndata) = address(token).call(data); require(success, "SafeERC20: low-level call failed"); if (returndata.length > 0) { // Return data is optional // solhint-disable-next-line max-line-length require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed"); } } } /** * @title Initializable * * @dev Helper contract to support initializer functions. To use it, replace * the constructor with a function that has the `initializer` modifier. * WARNING: Unlike constructors, initializer functions must be manually * invoked. This applies both to deploying an Initializable contract, as well * as extending an Initializable contract via inheritance. * WARNING: When used with inheritance, manual care must be taken to not invoke * a parent initializer twice, or ensure that all initializers are idempotent, * because this is not dealt with automatically as with constructors. */ contract Initializable { /** * @dev Indicates that the contract has been initialized. */ bool private initialized; /** * @dev Indicates that the contract is in the process of being initialized. */ bool private initializing; /** * @dev Modifier to use in the initializer function of a contract. */ modifier initializer() { require(initializing || isConstructor() || !initialized, "Contract instance has already been initialized"); bool isTopLevelCall = !initializing; if (isTopLevelCall) { initializing = true; initialized = true; } _; if (isTopLevelCall) { initializing = false; } } /// @dev Returns true if and only if the function is running in the constructor function isConstructor() private view returns (bool) { // extcodesize checks the size of the code stored in an address, and // address returns the current address. Since the code is still not // deployed when running a constructor, any checks on its code size will // yield zero, making it an effective way to detect if a contract is // under construction or not. address self = address(this); uint256 cs; assembly { cs := extcodesize(self) } return cs == 0; } // Reserved storage space to allow for layout changes in the future. uint256[50] private ______gap; } /* * @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 is Initializable { // 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; } } /** * @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 Initializable, 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), "ERC20: transfer to the zero address"); _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), "ERC20: mint to the zero address"); _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), "ERC20: burn from the zero address"); _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), "ERC20: approve from the zero address"); require(spender != address(0), "ERC20: approve to the zero address"); _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")); } uint256[50] private ______gap; } /** * @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), "Roles: account already has role"); 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), "Roles: account does not have role"); 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), "Roles: account is the zero address"); return role.bearer[account]; } } contract MinterRole is Initializable, Context { using Roles for Roles.Role; event MinterAdded(address indexed account); event MinterRemoved(address indexed account); Roles.Role private _minters; function initialize(address sender) public initializer { if (!isMinter(sender)) { _addMinter(sender); } } modifier onlyMinter() { require(isMinter(_msgSender()), "MinterRole: caller does not have the Minter role"); _; } function isMinter(address account) public view returns (bool) { return _minters.has(account); } function addMinter(address account) public onlyMinter { _addMinter(account); } function renounceMinter() public { _removeMinter(_msgSender()); } function _addMinter(address account) internal { _minters.add(account); emit MinterAdded(account); } function _removeMinter(address account) internal { _minters.remove(account); emit MinterRemoved(account); } uint256[50] private ______gap; } /** * @dev Extension of {ERC20} that adds a set of accounts with the {MinterRole}, * which have permission to mint (create) new tokens as they see fit. * * At construction, the deployer of the contract is the only minter. */ contract ERC20Mintable is Initializable, ERC20, MinterRole { function initialize(address sender) public initializer { MinterRole.initialize(sender); } /** * @dev See {ERC20-_mint}. * * Requirements: * * - the caller must have the {MinterRole}. */ function mint(address account, uint256 amount) public onlyMinter returns (bool) { _mint(account, amount); return true; } uint256[50] private ______gap; } /** * @dev Extension of {ERC20Mintable} that adds a cap to the supply of tokens. */ contract ERC20Capped is Initializable, ERC20Mintable { uint256 private _cap; /** * @dev Sets the value of the `cap`. This value is immutable, it can only be * set once during construction. */ function initialize(uint256 cap, address sender) public initializer { ERC20Mintable.initialize(sender); require(cap > 0, "ERC20Capped: cap is 0"); _cap = cap; } /** * @dev Returns the cap on the token's total supply. */ function cap() public view returns (uint256) { return _cap; } /** * @dev See {ERC20Mintable-mint}. * * Requirements: * * - `value` must not cause the total supply to go over the cap. */ function _mint(address account, uint256 value) internal { require(totalSupply().add(value) <= _cap, "ERC20Capped: cap exceeded"); super._mint(account, value); } uint256[50] private ______gap; } contract PauserRole is Initializable, Context { using Roles for Roles.Role; event PauserAdded(address indexed account); event PauserRemoved(address indexed account); Roles.Role private _pausers; function initialize(address sender) public initializer { if (!isPauser(sender)) { _addPauser(sender); } } modifier onlyPauser() { require(isPauser(_msgSender()), "PauserRole: caller does not have the Pauser role"); _; } function isPauser(address account) public view returns (bool) { return _pausers.has(account); } function addPauser(address account) public onlyPauser { _addPauser(account); } function renouncePauser() public { _removePauser(_msgSender()); } function _addPauser(address account) internal { _pausers.add(account); emit PauserAdded(account); } function _removePauser(address account) internal { _pausers.remove(account); emit PauserRemoved(account); } uint256[50] private ______gap; } /** * @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 Initializable, 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. */ function initialize(address sender) public initializer { PauserRole.initialize(sender); _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, "Pausable: paused"); _; } /** * @dev Modifier to make a function callable only when the contract is paused. */ modifier whenPaused() { require(_paused, "Pausable: not 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()); } uint256[50] private ______gap; } /** * @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 Initializable, ERC20, Pausable { function initialize(address sender) public initializer { Pausable.initialize(sender); } 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); } uint256[50] private ______gap; } /** * @title Continuous Offering abstract contract * @notice A shared base for various offerings from Fairmint. */ contract ContinuousOffering is ERC20Pausable, ERC20Capped, IERC20Detailed { using SafeMath for uint; using Sqrt for uint; using SafeERC20 for IERC20; /** * Events */ event Buy( address indexed _from, address indexed _to, uint _currencyValue, uint _fairValue ); event Sell( address indexed _from, address indexed _to, uint _currencyValue, uint _fairValue ); event Burn( address indexed _from, uint _fairValue ); event StateChange( uint _previousState, uint _newState ); /** * Constants */ /// @notice The default state uint internal constant STATE_INIT = 0; /// @notice The state after initGoal has been reached uint internal constant STATE_RUN = 1; /// @notice The state after closed by the `beneficiary` account from STATE_RUN uint internal constant STATE_CLOSE = 2; /// @notice The state after closed by the `beneficiary` account from STATE_INIT uint internal constant STATE_CANCEL = 3; /// @notice When multiplying 2 terms, the max value is 2^128-1 uint internal constant MAX_BEFORE_SQUARE = 2**128 - 1; /// @notice The denominator component for values specified in basis points. uint internal constant BASIS_POINTS_DEN = 10000; /// @notice The max `totalSupply() + burnedSupply` /// @dev This limit ensures that the DAT's formulas do not overflow ( uint) public initInvestors; /// @notice The initial number of FAIR created at initialization for the beneficiary. /// Technically however, this variable is not a constant as we must always have ///`init_reserve>=total_supply+burnt_supply` which means that `init_reserve` will be automatically /// decreased to equal `total_supply+burnt_supply` in case `init_reserve>total_supply+burnt_supply` /// after an investor sells his FAIRs. /// @dev Organizations may move these tokens into vesting contract(s) uint public initReserve; /// @notice The investment reserve of the c-org. Defines the percentage of the value invested that is /// automatically funneled and held into the buyback_reserve expressed in basis points. /// Internal since this is n/a to all derivative contracts. uint internal __investmentReserveBasisPoints; /// @dev unused slot which remains to ensure compatible upgrades uint private __openUntilAtLeast; /// @notice The minimum amount of `currency` investment accepted. uint public minInvestment; /// @dev The revenue commitment of the organization. Defines the percentage of the value paid through the contract /// that is automatically funneled and held into the buyback_reserve expressed in basis points. /// Internal since this is n/a to all derivative contracts. uint internal __revenueCommitmentBasisPoints; /// @notice The current state of the contract. /// @dev See the constants above for possible state values. uint public state; /// @dev If this value changes we need to reconstruct the DOMAIN_SEPARATOR string public constant version = "3"; // --- EIP712 niceties --- // Original source: https://etherscan.io/address/0x6b175474e89094c44da98b954eedeac495271d0f#code mapping (address => uint) public nonces; bytes32 public DOMAIN_SEPARATOR; // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"); bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9; // The success fee (expressed in currency) that will be earned by setupFeeRecipient as soon as initGoal // is reached. We must have setup_fee <= buy_slope*init_goal^(2)/2 uint public setupFee; // The recipient of the setup_fee once init_goal is reached address payable public setupFeeRecipient; /// @notice The minimum time before which the c-org contract cannot be closed once the contract has /// reached the `run` state. /// @dev When updated, the new value of `minimum_duration` cannot be earlier than the previous value. uint public minDuration; /// @dev Initialized at `0` and updated when the contract switches from `init` state to `run` state /// or when the initial trial period ends. uint public __startedOn; /// @notice The max possible value uint internal constant MAX_UINT = 2**256 - 1; // keccak256("PermitBuy(address from,address to,uint256 currencyValue,uint256 minTokensBought,uint256 nonce,uint256 deadline)"); bytes32 public constant PERMIT_BUY_TYPEHASH = 0xaf42a244b3020d6a2253d9f291b4d3e82240da42b22129a8113a58aa7a3ddb6a; // keccak256("PermitSell(address from,address to,uint256 quantityToSell,uint256 minCurrencyReturned,uint256 nonce,uint256 deadline)"); bytes32 public constant PERMIT_SELL_TYPEHASH = 0x5dfdc7fb4c68a4c249de5e08597626b84fbbe7bfef4ed3500f58003e722cc548; modifier authorizeTransfer( address _from, address _to, uint _value, bool _isSell ) { if(address(whitelist) != address(0)) { //automatically activate wallet _from //does not activate if, //1. _from is zero address, //2. it is burn if(!whitelist.walletActivated(_from) && _from != address(0) && !(_to == address(0) && !_isSell)){ whitelist.activateWallet(_from); } //automatically activate wallet _to //does not activate if, //1. _to is zero address, if(!whitelist.walletActivated(_to) && _to != address(0)){ whitelist.activateWallet(_to); } // This is not set for the minting of initialReserve whitelist.authorizeTransfer(_from, _to, _value, _isSell); } _; if(address(whitelist) != address(0)){ //automatically deactivates _from if _from's balance is zero if(balanceOf(_from) == 0 && _from != address(0) && !(_to==address(0) && !_isSell)){ //deactivate wallets without balance whitelist.deactivateWallet(_from); } } } /** * Buyback reserve */ /// @notice The total amount of currency value currently locked in the contract and available to sellers. function buybackReserve() public view returns (uint) { uint reserve = address(this).balance; if(address(currency) != address(0)) { reserve = currency.balanceOf(address(this)); } if(reserve > MAX_BEFORE_SQUARE) { /// Math: If the reserve becomes excessive, cap the value to prevent overflowing in other formulas return MAX_BEFORE_SQUARE; } return reserve; } /** * Functions required by the ERC-20 token standard */ /// @dev Moves tokens from one account to another if authorized. function _transfer( address _from, address _to, uint _amount ) internal authorizeTransfer(_from, _to, _amount, false) { require(state != STATE_INIT || _from == beneficiary, "ONLY_BENEFICIARY_DURING_INIT"); super._transfer(_from, _to, _amount); } /// @dev Removes tokens from the circulating supply. function _burn( address _from, uint _amount, bool _isSell ) internal authorizeTransfer(_from, address(0), _amount, _isSell) { super._burn(_from, _amount); if(!_isSell) { // This is a burn require(state == STATE_RUN, "INVALID_STATE"); // SafeMath not required as we cap how high this value may get during mint burnedSupply += _amount; emit Burn(_from, _amount); } } /// @notice Called to mint tokens on `buy`. function _mint( address _to, uint _quantity ) internal authorizeTransfer(address(0), _to, _quantity, false) { super._mint(_to, _quantity); // Math: If this value got too large, the DAT may overflow on sell require(totalSupply().add(burnedSupply) <= MAX_SUPPLY, "EXCESSIVE_SUPPLY"); } /** * Transaction Helpers */ /// @notice Confirms the transfer of `_quantityToInvest` currency to the contract. function _collectInvestment( address payable _from, uint _quantityToInvest, uint _msgValue, bool _refundRemainder ) internal { if(address(currency) == address(0)) { // currency is ETH if(_refundRemainder) { // Math: if _msgValue was not sufficient then revert uint refund = _msgValue.sub(_quantityToInvest); if(refund > 0) { Address.sendValue(msg.sender, refund); } } else { require(_quantityToInvest == _msgValue, "INCORRECT_MSG_VALUE"); } } else { // currency is ERC20 require(_msgValue == 0, "DO_NOT_SEND_ETH"); currency.safeTransferFrom(_from, address(this), _quantityToInvest); } } /// @dev Send `_amount` currency from the contract to the `_to` account. function _transferCurrency( address payable _to, uint _amount ) internal { if(_amount > 0) { if(address(currency) == address(0)) { Address.sendValue(_to, _amount); } else { currency.safeTransfer(_to, _amount); } } } /** * Config / Control */ /// @notice Called once after deploy to set the initial configuration. /// None of the values provided here may change once initially set. /// @dev using the init pattern in order to support zos upgrades function _initialize( uint _initReserve, address _currencyAddress, uint _initGoal, uint _buySlopeNum, uint _buySlopeDen, uint _setupFee, address payable _setupFeeRecipient ) internal { // The ERC-20 implementation will confirm initialize is only run once ERC20Capped.initialize((5000000 * (10 ** 18)), msg.sender); // Also update the pausable setting _addPauser(msg.sender); require(_buySlopeNum > 0, "INVALID_SLOPE_NUM"); require(_buySlopeDen > 0, "INVALID_SLOPE_DEN"); require(_buySlopeNum < MAX_BEFORE_SQUARE, "EXCESSIVE_SLOPE_NUM"); require(_buySlopeDen < MAX_BEFORE_SQUARE, "EXCESSIVE_SLOPE_DEN"); buySlopeNum = _buySlopeNum; buySlopeDen = _buySlopeDen; // Setup Fee require(_setupFee == 0 || _setupFeeRecipient != address(0), "MISSING_SETUP_FEE_RECIPIENT"); require(_setupFeeRecipient == address(0) || _setupFee != 0, "MISSING_SETUP_FEE"); // setup_fee <= (n/d)*(g^2)/2 uint initGoalInCurrency = _initGoal * _initGoal; initGoalInCurrency = initGoalInCurrency.mul(_buySlopeNum); initGoalInCurrency /= 2 * _buySlopeDen; require(_setupFee <= initGoalInCurrency, "EXCESSIVE_SETUP_FEE"); setupFee = _setupFee; setupFeeRecipient = _setupFeeRecipient; // Set default values (which may be updated using `updateConfig`) uint decimals = 18; if(_currencyAddress != address(0)) { decimals = IERC20Detailed(_currencyAddress).decimals(); } minInvestment = 100 * (10 ** decimals); beneficiary = msg.sender; control = msg.sender; feeCollector = msg.sender; // Save currency currency = IERC20(_currencyAddress); // Mint the initial reserve if(_initReserve > 0) { initReserve = _initReserve; _mint(beneficiary, initReserve); } initializeDomainSeparator(); } /// @notice Used to initialize the domain separator used in meta-transactions /// @dev This is separate from `initialize` to allow upgraded contracts to update the version /// There is no harm in calling this multiple times / no permissions required function initializeDomainSeparator() public { uint id; // solium-disable-next-line assembly { id := chainid() } DOMAIN_SEPARATOR = keccak256( abi.encode( keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"), keccak256(bytes(name())), keccak256(bytes(version)), id, address(this) ) ); } function _updateConfig( address _whitelistAddress, address payable _beneficiary, address _control, address payable _feeCollector, uint _feeBasisPoints, uint _minInvestment, uint _minDuration ) internal { // This require(also confirms that initialize has been called. require(msg.sender == control, "CONTROL_ONLY"); // address(0) is okay whitelist = IWhitelist(_whitelistAddress); require(_control != address(0), "INVALID_ADDRESS"); control = _control; require(_feeCollector != address(0), "INVALID_ADDRESS"); feeCollector = _feeCollector; require(_feeBasisPoints <= BASIS_POINTS_DEN, "INVALID_FEE"); feeBasisPoints = _feeBasisPoints; require(_minInvestment > 0, "INVALID_MIN_INVESTMENT"); minInvestment = _minInvestment; require(_minDuration >= minDuration, "MIN_DURATION_MAY_NOT_BE_REDUCED"); minDuration = _minDuration; if(beneficiary != _beneficiary) { require(_beneficiary != address(0), "INVALID_ADDRESS"); uint tokens = balanceOf(beneficiary); initInvestors[_beneficiary] = initInvestors[_beneficiary].add(initInvestors[beneficiary]); initInvestors[beneficiary] = 0; if(tokens > 0) { _transfer(beneficiary, _beneficiary, tokens); } beneficiary = _beneficiary; } } /** * Functions for our business logic */ /// @notice Burn the amount of tokens from the address msg.sender if authorized. /// @dev Note that this is not the same as a `sell` via the DAT. function burn( uint _amount ) public { _burn(msg.sender, _amount, false); } /// @notice Burn the amount of tokens from the given address if approved. function burnFrom( address _from, uint _amount ) public { _approve(_from, msg.sender, allowance(_from, msg.sender).sub(_amount, "ERC20: burn amount exceeds allowance")); _burn(_from, _amount, false); } // Buy /// @dev Distributes _value currency between the buybackReserve, beneficiary, and feeCollector. function _distributeInvestment(uint _value) internal; /// @notice Calculate how many FAIR tokens you would buy with the given amount of currency if `buy` was called now. /// @param _currencyValue How much currency to spend in order to buy FAIR. function estimateBuyValue( uint _currencyValue ) public view returns (uint) { if(_currencyValue < minInvestment) { return 0; } /// Calculate the tokenValue for this investment uint tokenValue; if(state == STATE_INIT) { uint currencyValue = _currencyValue; uint _totalSupply = totalSupply(); // (buy_slope*init_goal)*(init_goal+init_reserve-total_supply) // n/d: buy_slope (MAX_BEFORE_SQUARE / MAX_BEFORE_SQUARE) // g: init_goal (MAX_BEFORE_SQUARE) // t: total_supply (MAX_BEFORE_SQUARE) // r: init_reserve (MAX_BEFORE_SQUARE) // source: ((n/d)*g)*(g+r-t) // impl: (g n (g + r - t))/(d) uint max = BigDiv.bigDiv2x1( initGoal * buySlopeNum, initGoal + initReserve - _totalSupply, buySlopeDen ); if(currencyValue > max) { currencyValue = max; } // Math: worst case // MAX * MAX_BEFORE_SQUARE // / MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE tokenValue = BigDiv.bigDiv2x1( currencyValue, buySlopeDen, initGoal * buySlopeNum ); if(currencyValue != _currencyValue) { currencyValue = _currencyValue - max; // ((2*next_amount/buy_slope)+init_goal^2)^(1/2)-init_goal // a: next_amount | currencyValue // n/d: buy_slope (MAX_BEFORE_SQUARE / MAX_BEFORE_SQUARE) // g: init_goal (MAX_BEFORE_SQUARE/2) // r: init_reserve (MAX_BEFORE_SQUARE/2) // sqrt(((2*a/(n/d))+g^2)-g // sqrt((2 d a + n g^2)/n) - g // currencyValue == 2 d a uint temp = 2 * buySlopeDen; currencyValue = temp.mul(currencyValue); // temp == g^2 temp = initGoal; temp *= temp; // temp == n g^2 temp = temp.mul(buySlopeNum); // temp == (2 d a) + n g^2 temp = currencyValue.add(temp); // temp == (2 d a + n g^2)/n temp /= buySlopeNum; // temp == sqrt((2 d a + n g^2)/n) temp = temp.sqrt(); // temp == sqrt((2 d a + n g^2)/n) - g temp -= initGoal; tokenValue = tokenValue.add(temp); } } else if(state == STATE_RUN) { // initReserve is reduced on sell as necessary to ensure that this line will not overflow uint supply = totalSupply() + burnedSupply - initReserve; // Math: worst case // MAX * 2 * MAX_BEFORE_SQUARE // / MAX_BEFORE_SQUARE tokenValue = BigDiv.bigDiv2x1( _currencyValue, 2 * buySlopeDen, buySlopeNum ); // Math: worst case MAX + (MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE) tokenValue = tokenValue.add(supply * supply); tokenValue = tokenValue.sqrt(); // Math: small chance of underflow due to possible rounding in sqrt tokenValue = tokenValue.sub(supply); } else { // invalid state return 0; } return tokenValue; } function _buy( address payable _from, address _to, uint _currencyValue, uint _minTokensBought ) internal { require(_to != address(0), "INVALID_ADDRESS"); require(_minTokensBought > 0, "MUST_BUY_AT_LEAST_1"); // Calculate the tokenValue for this investment uint tokenValue = estimateBuyValue(_currencyValue); require(tokenValue >= _minTokensBought, "PRICE_SLIPPAGE"); emit Buy(_from, _to, _currencyValue, tokenValue); _collectInvestment(_from, _currencyValue, msg.value, false); // Update state, initInvestors, and distribute the investment when appropriate if(state == STATE_INIT) { // Math worst case: MAX_BEFORE_SQUARE initInvestors[_to] += tokenValue; // Math worst case: // MAX_BEFORE_SQUARE + MAX_BEFORE_SQUARE if(totalSupply() + tokenValue - initReserve >= initGoal) { emit StateChange(state, STATE_RUN); state = STATE_RUN; if(__startedOn == 0) { __startedOn = block.timestamp; } // Math worst case: // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE/2 // / MAX_BEFORE_SQUARE uint beneficiaryContribution = BigDiv.bigDiv2x1( initInvestors[beneficiary], buySlopeNum * initGoal, buySlopeDen ); if(setupFee > 0) { _transferCurrency(setupFeeRecipient, setupFee); if(beneficiaryContribution > setupFee) { beneficiaryContribution -= setupFee; } else { beneficiaryContribution = 0; } } _distributeInvestment(buybackReserve().sub(beneficiaryContribution)); } } else // implied: if(state == STATE_RUN) { if(_to != beneficiary) { _distributeInvestment(_currencyValue); } } _mint(_to, tokenValue); } /// @notice Purchase FAIR tokens with the given amount of currency. /// @param _to The account to receive the FAIR tokens from this purchase. /// @param _currencyValue How much currency to spend in order to buy FAIR. /// @param _minTokensBought Buy at least this many FAIR tokens or the transaction reverts. /// @dev _minTokensBought is necessary as the price will change if some elses transaction mines after /// yours was submitted. function buy( address _to, uint _currencyValue, uint _minTokensBought ) public payable { _buy(msg.sender, _to, _currencyValue, _minTokensBought); } /// @notice Allow users to sign a message authorizing a buy function permitBuy( address payable _from, address _to, uint _currencyValue, uint _minTokensBought, uint _deadline, uint8 _v, bytes32 _r, bytes32 _s ) external { require(_deadline >= block.timestamp, "EXPIRED"); bytes32 digest = keccak256(abi.encode(PERMIT_BUY_TYPEHASH, _from, _to, _currencyValue, _minTokensBought, nonces[_from]++, _deadline)); digest = keccak256( abi.encodePacked( "\x19\x01", DOMAIN_SEPARATOR, digest ) ); address recoveredAddress = ecrecover(digest, _v, _r, _s); require(recoveredAddress != address(0) && recoveredAddress == _from, "INVALID_SIGNATURE"); _buy(_from, _to, _currencyValue, _minTokensBought); } /// Sell function estimateSellValue( uint _quantityToSell ) public view returns(uint) { uint reserve = buybackReserve(); // Calculate currencyValue for this sale uint currencyValue; if(state == STATE_RUN) { uint supply = totalSupply() + burnedSupply; // buyback_reserve = r // total_supply = t // burnt_supply = b // amount = a // source: (t+b)*a*(2*r)/((t+b)^2)-(((2*r)/((t+b)^2)*a^2)/2)+((2*r)/((t+b)^2)*a*b^2)/(2*(t)) // imp: (a b^2 r)/(t (b + t)^2) + (2 a r)/(b + t) - (a^2 r)/(b + t)^2 // Math: burnedSupply is capped in FAIR such that the square will never overflow // Math worst case: // MAX * MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE/2 // / MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE/2 currencyValue = BigDiv.bigDiv2x2( _quantityToSell.mul(reserve), burnedSupply * burnedSupply, totalSupply(), supply * supply ); // Math: worst case currencyValue is MAX_BEFORE_SQUARE (max reserve, 1 supply) // Math worst case: // MAX * 2 * MAX_BEFORE_SQUARE uint temp = _quantityToSell.mul(2 * reserve); temp /= supply; // Math: worst-case temp is MAX_BEFORE_SQUARE (max reserve, 1 supply) // Math: considering the worst-case for currencyValue and temp, this can never overflow currencyValue += temp; // Math: worst case // MAX * MAX * MAX_BEFORE_SQUARE // / MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE/2 temp = BigDiv.bigDiv2x1RoundUp( _quantityToSell.mul(_quantityToSell), reserve, supply * supply ); if(currencyValue > temp) { currencyValue -= temp; } else { currencyValue = 0; } } else if(state == STATE_CLOSE) { // Math worst case // MAX * MAX_BEFORE_SQUARE currencyValue = _quantityToSell.mul(reserve); currencyValue /= totalSupply(); } else { // STATE_INIT or STATE_CANCEL // Math worst case: // MAX * MAX_BEFORE_SQUARE currencyValue = _quantityToSell.mul(reserve); // Math: FAIR blocks initReserve from being burned unless we reach the RUN state which prevents an underflow currencyValue /= totalSupply() - initReserve; } return currencyValue; } function _sell( address _from, address payable _to, uint _quantityToSell, uint _minCurrencyReturned ) internal { require(_from != beneficiary || state >= STATE_CLOSE, "BENEFICIARY_ONLY_SELL_IN_CLOSE_OR_CANCEL"); require(_minCurrencyReturned > 0, "MUST_SELL_AT_LEAST_1"); uint currencyValue = estimateSellValue(_quantityToSell); require(currencyValue >= _minCurrencyReturned, "PRICE_SLIPPAGE"); if(state == STATE_INIT || state == STATE_CANCEL) { initInvestors[_from] = initInvestors[_from].sub(_quantityToSell); } _burn(_from, _quantityToSell, true); uint supply = totalSupply() + burnedSupply; if(supply < initReserve) { initReserve = supply; } _transferCurrency(_to, currencyValue); emit Sell(_from, _to, currencyValue, _quantityToSell); } /// @notice Sell FAIR tokens for at least the given amount of currency. /// @param _to The account to receive the currency from this sale. /// @param _quantityToSell How many FAIR tokens to sell for currency value. /// @param _minCurrencyReturned Get at least this many currency tokens or the transaction reverts. /// @dev _minCurrencyReturned is necessary as the price will change if some elses transaction mines after /// yours was submitted. function sell( address payable _to, uint _quantityToSell, uint _minCurrencyReturned ) public { _sell(msg.sender, _to, _quantityToSell, _minCurrencyReturned); } /// @notice Allow users to sign a message authorizing a sell function permitSell( address _from, address payable _to, uint _quantityToSell, uint _minCurrencyReturned, uint _deadline, uint8 _v, bytes32 _r, bytes32 _s ) external { require(_deadline >= block.timestamp, "EXPIRED"); bytes32 digest = keccak256(abi.encode(PERMIT_SELL_TYPEHASH, _from, _to, _quantityToSell, _minCurrencyReturned, nonces[_from]++, _deadline)); digest = keccak256( abi.encodePacked( "\x19\x01", DOMAIN_SEPARATOR, digest ) ); address recoveredAddress = ecrecover(digest, _v, _r, _s); require(recoveredAddress != address(0) && recoveredAddress == _from, "INVALID_SIGNATURE"); _sell(_from, _to, _quantityToSell, _minCurrencyReturned); } /// Close /// @notice Called by the beneficiary account to STATE_CLOSE or STATE_CANCEL the c-org, /// preventing any more tokens from being minted. /// @dev Requires an `exitFee` to be paid. If the currency is ETH, include a little more than /// what appears to be required and any remainder will be returned to your account. This is /// because another user may have a transaction mined which changes the exitFee required. /// For other `currency` types, the beneficiary account will be billed the exact amount required. function _close() internal { require(msg.sender == beneficiary, "BENEFICIARY_ONLY"); if(state == STATE_INIT) { // Allow the org to cancel anytime if the initGoal was not reached. emit StateChange(state, STATE_CANCEL); state = STATE_CANCEL; } else if(state == STATE_RUN) { // Collect the exitFee and close the c-org. require(MAX_UINT - minDuration > __startedOn, "MAY_NOT_CLOSE"); require(minDuration + __startedOn <= block.timestamp, "TOO_EARLY"); emit StateChange(state, STATE_CLOSE); state = STATE_CLOSE; } else { revert("INVALID_STATE"); } } // --- Approve by signature --- // EIP-2612 // Original source: https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2ERC20.sol function permit( address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s ) external { require(deadline >= block.timestamp, "EXPIRED"); bytes32 digest = keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline)); digest = keccak256( abi.encodePacked( "\x19\x01", DOMAIN_SEPARATOR, digest ) ); address recoveredAddress = ecrecover(digest, v, r, s); require(recoveredAddress != address(0) && recoveredAddress == owner, "INVALID_SIGNATURE"); _approve(owner, spender, value); } /** * @dev Returns the name of the token. */ function name() public view returns (string memory) { return "Vision Token"; } /** * @dev Returns the symbol of the token, usually a shorter version of the * name. */ function symbol() public view returns (string memory) { return "VISION"; } /** * @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 18; } uint256[50] private __gap; } /** * @title Decentralized Autonomous Trust * This contract is the reference implementation provided by Fairmint for a * Decentralized Autonomous Trust as described in the continuous * organization whitepaper (https://github.com/c-org/whitepaper) and * specified here: https://github.com/fairmint/c-org/wiki. Use at your own * risk. If you have question or if you're looking for a ready-to-use * solution using this contract, you might be interested in Fairmint's * offering. Do not hesitate to get in touch with us: https://fairmint.co */ contract VisionToken is ContinuousOffering { event Close(uint _exitFee); event Pay(address indexed _from, uint _currencyValue); event UpdateConfig( address _whitelistAddress, address indexed _beneficiary, address indexed _control, address indexed _feeCollector, uint _revenueCommitmentBasisPoints, uint _feeBasisPoints, uint _minInvestment, uint _minDuration ); /// @notice The revenue commitment of the organization. Defines the percentage of the value paid through the contract /// that is automatically funneled and held into the buyback_reserve expressed in basis points. /// Internal since this is n/a to all derivative contracts. function revenueCommitmentBasisPoints() public view returns (uint) { return __revenueCommitmentBasisPoints; } /// @notice The investment reserve of the c-org. Defines the percentage of the value invested that is /// automatically funneled and held into the buyback_reserve expressed in basis points. /// Internal since this is n/a to all derivative contracts. function investmentReserveBasisPoints() public view returns (uint) { return __investmentReserveBasisPoints; } /// @notice Initialized at `0` and updated when the contract switches from `init` state to `run` state /// with the current timestamp. function runStartedOn() public view returns (uint) { return __startedOn; } function initialize( uint _initReserve, address _currencyAddress, uint _initGoal, uint _buySlopeNum, uint _buySlopeDen, uint _investmentReserveBasisPoints, uint _setupFee, address payable _setupFeeRecipient ) public { // _initialize will enforce this is only called once super._initialize( _initReserve, _currencyAddress, _initGoal, _buySlopeNum, _buySlopeDen, _setupFee, _setupFeeRecipient ); // Set initGoal, which in turn defines the initial state if(_initGoal == 0) { emit StateChange(state, STATE_RUN); state = STATE_RUN; __startedOn = block.timestamp; } else { // Math: If this value got too large, the DAT would overflow on sell require(_initGoal < MAX_SUPPLY, "EXCESSIVE_GOAL"); initGoal = _initGoal; } // 100% or less require(_investmentReserveBasisPoints <= BASIS_POINTS_DEN, "INVALID_RESERVE"); __investmentReserveBasisPoints = _investmentReserveBasisPoints; } /// Close function estimateExitFee(uint _msgValue) public view returns (uint) { uint exitFee; if (state == STATE_RUN) { uint reserve = buybackReserve(); reserve = reserve.sub(_msgValue); // Source: t*(t+b)*(n/d)-r // Implementation: (b n t)/d + (n t^2)/d - r uint _totalSupply = totalSupply(); // Math worst case: // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE exitFee = BigDiv.bigDiv2x1( _totalSupply, burnedSupply * buySlopeNum, buySlopeDen ); // Math worst case: // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE exitFee += BigDiv.bigDiv2x1( _totalSupply, buySlopeNum * _totalSupply, buySlopeDen ); // Math: this if condition avoids a potential overflow if (exitFee <= reserve) { exitFee = 0; } else { exitFee -= reserve; } } return exitFee; } /// @notice Called by the beneficiary account to STATE_CLOSE or STATE_CANCEL the c-org, /// preventing any more tokens from being minted. /// @dev Requires an `exitFee` to be paid. If the currency is ETH, include a little more than /// what appears to be required and any remainder will be returned to your account. This is /// because another user may have a transaction mined which changes the exitFee required. /// For other `currency` types, the beneficiary account will be billed the exact amount required. function close() public payable { uint exitFee = 0; if (state == STATE_RUN) { exitFee = estimateExitFee(msg.value); _collectInvestment(msg.sender, exitFee, msg.value, true); } super._close(); emit Close(exitFee); } /// Pay /// @dev Pay the organization on-chain. /// @param _currencyValue How much currency which was paid. function pay(uint _currencyValue) public payable { _collectInvestment(msg.sender, _currencyValue, msg.value, false); require(state == STATE_RUN, "INVALID_STATE"); require(_currencyValue > 0, "MISSING_CURRENCY"); // Send a portion of the funds to the beneficiary, the rest is added to the buybackReserve // Math: if _currencyValue is < (2^256 - 1) / 10000 this will not overflow uint reserve = _currencyValue.mul(__revenueCommitmentBasisPoints); reserve /= BASIS_POINTS_DEN; // Math: this will never underflow since revenueCommitmentBasisPoints is capped to BASIS_POINTS_DEN _transferCurrency(beneficiary, _currencyValue - reserve); emit Pay(msg.sender, _currencyValue); } /// @notice Pay the organization on-chain without minting any tokens. /// @dev This allows you to add funds directly to the buybackReserve. function() external payable { require(address(currency) == address(0), "ONLY_FOR_CURRENCY_ETH"); } function updateConfig( address _whitelistAddress, address payable _beneficiary, address _control, address payable _feeCollector, uint _feeBasisPoints, uint _revenueCommitmentBasisPoints, uint _minInvestment, uint _minDuration ) public { _updateConfig( _whitelistAddress, _beneficiary, _control, _feeCollector, _feeBasisPoints, _minInvestment, _minDuration ); require( _revenueCommitmentBasisPoints <= BASIS_POINTS_DEN, "INVALID_COMMITMENT" ); require( _revenueCommitmentBasisPoints >= __revenueCommitmentBasisPoints, "COMMITMENT_MAY_NOT_BE_REDUCED" ); __revenueCommitmentBasisPoints = _revenueCommitmentBasisPoints; emit UpdateConfig( _whitelistAddress, _beneficiary, _control, _feeCollector, _revenueCommitmentBasisPoints, _feeBasisPoints, _minInvestment, _minDuration ); } /// @notice A temporary function to set `runStartedOn`, to be used by contracts which were /// already deployed before this feature was introduced. /// @dev This function will be removed once known users have called the function. function initializeRunStartedOn( uint _runStartedOn ) external { require(msg.sender == control, "CONTROL_ONLY"); require(state == STATE_RUN, "ONLY_CALL_IN_RUN"); require(__startedOn == 0, "ONLY_CALL_IF_NOT_AUTO_SET"); require(_runStartedOn <= block.timestamp, "DATE_MUST_BE_IN_PAST"); __startedOn = _runStartedOn; } /// @dev Distributes _value currency between the buybackReserve, beneficiary, and feeCollector. function _distributeInvestment( uint _value ) internal { // Rounding favors buybackReserve, then beneficiary, and feeCollector is last priority. // Math: if investment value is < (2^256 - 1) / 10000 this will never overflow. // Except maybe with a huge single investment, but they can try again with multiple smaller investments. uint reserve = __investmentReserveBasisPoints.mul(_value); reserve /= BASIS_POINTS_DEN; reserve = _value.sub(reserve); uint fee = reserve.mul(feeBasisPoints); fee /= BASIS_POINTS_DEN; // Math: since feeBasisPoints is <= BASIS_POINTS_DEN, this will never underflow. _transferCurrency(beneficiary, reserve - fee); _transferCurrency(feeCollector, fee); } }

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