pragma solidity ^0.5.2; /** * @title SafeMath * @dev Unsigned math operations with safety checks that revert on error */ library SafeMath { /** * @dev Multiplies two unsigned integers, reverts on 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-solidity/pull/522 if (a == 0) { return 0; } uint256 c = a * b; require(c / a == b); return c; } /** * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero. */ function div(uint256 a, uint256 b) internal pure returns (uint256) { // Solidity only automatically asserts when dividing by 0 require(b > 0); uint256 c = a / b; // assert(a == b * c + a % b); // There is no case in which this doesn't hold return c; } /** * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend). */ function sub(uint256 a, uint256 b) internal pure returns (uint256) { require(b <= a); uint256 c = a - b; return c; } /** * @dev Adds two unsigned integers, reverts on overflow. */ function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; require(c >= a); return c; } /** * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo), * reverts when dividing by zero. */ function mod(uint256 a, uint256 b) internal pure returns (uint256) { require(b != 0); return a % b; } } /** * @title ERC20 interface * @dev see https://github.com/ethereum/EIPs/issues/20 */ interface IERC20 { function transfer(address to, uint256 value) external returns (bool); function approve(address spender, uint256 value) external returns (bool); function transferFrom(address from, address to, uint256 value) external returns (bool); function totalSupply() external view returns (uint256); function balanceOf(address who) external view returns (uint256); function allowance(address owner, address spender) external view returns (uint256); event Transfer(address indexed from, address indexed to, uint256 value); event Approval(address indexed owner, address indexed spender, uint256 value); } /** * @title SafeERC20 * @dev Wrappers around ERC20 operations that throw on failure. * 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; function safeTransfer(IERC20 token, address to, uint256 value) internal { require(token.transfer(to, value)); } function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal { require(token.transferFrom(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' require((value == 0) || (token.allowance(msg.sender, spender) == 0)); require(token.approve(spender, value)); } function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).add(value); require(token.approve(spender, newAllowance)); } function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).sub(value); require(token.approve(spender, newAllowance)); } } /** * @title Helps contracts guard against reentrancy attacks. * @author Remco Bloemen <remco@2π.com>, Eenae <alexey@mixbytes.io> * @dev If you mark a function `nonReentrant`, you should also * mark it `external`. */ contract ReentrancyGuard { /// @dev counter to allow mutex lock with only one SSTORE operation uint256 private _guardCounter; constructor () internal { // The counter starts at one to prevent changing it from zero to a non-zero // value, which is a more expensive operation. _guardCounter = 1; } /** * @dev Prevents a contract from calling itself, directly or indirectly. * Calling a `nonReentrant` function from another `nonReentrant` * function is not supported. It is possible to prevent this from happening * by making the `nonReentrant` function external, and make it call a * `private` function that does the actual work. */ modifier nonReentrant() { _guardCounter += 1; uint256 localCounter = _guardCounter; _; require(localCounter == _guardCounter); } } /** * @title Crowdsale * @dev Crowdsale is a base contract for managing a token crowdsale, * allowing investors to purchase tokens with ether. This contract implements * such functionality in its most fundamental form and can be extended to provide additional * functionality and/or custom behavior. * The external interface represents the basic interface for purchasing tokens, and conform * the base architecture for crowdsales. They are *not* intended to be modified / overridden. * The internal interface conforms the extensible and modifiable surface of crowdsales. Override * the methods to add functionality. Consider using 'super' where appropriate to concatenate * behavior. */ contract Crowdsale is ReentrancyGuard { using SafeMath for uint256; using SafeERC20 for IERC20; // The token being sold IERC20 private _token; // Address where funds are collected address payable private _wallet; // How many token units a buyer gets per wei. // The rate is the conversion between wei and the smallest and indivisible token unit. // So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK // 1 wei will give you 1 unit, or 0.001 TOK. uint256 private _rate; // Amount of wei raised uint256 private _weiRaised; /** * Event for token purchase logging * @param purchaser who paid for the tokens * @param beneficiary who got the tokens * @param value weis paid for purchase * @param amount amount of tokens purchased */ event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount); /** * @param rate Number of token units a buyer gets per wei * @dev The rate is the conversion between wei and the smallest and indivisible * token unit. So, if you are using a rate of 1 with a ERC20Detailed token * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK. * @param wallet Address where collected funds will be forwarded to * @param token Address of the token being sold */ constructor (uint256 rate, address payable wallet, IERC20 token) public { require(rate > 0); require(wallet != address(0)); require(address(token) != address(0)); _rate = rate; _wallet = wallet; _token = token; } /** * @dev fallback function ***DO NOT OVERRIDE*** * Note that other contracts will transfer fund with a base gas stipend * of 2300, which is not enough to call buyTokens. Consider calling * buyTokens directly when purchasing tokens from a contract. */ function () external payable { buyTokens(msg.sender); } /** * @return the token being sold. */ function token() public view returns (IERC20) { return _token; } /** * @return the address where funds are collected. */ function wallet() public view returns (address payable) { return _wallet; } /** * @return the number of token units a buyer gets per wei. */ function rate() public view returns (uint256) { return _rate; } /** * @return the amount of wei raised. */ function weiRaised() public view returns (uint256) { return _weiRaised; } /** * @dev low level token purchase ***DO NOT OVERRIDE*** * This function has a non-reentrancy guard, so it shouldn't be called by * another `nonReentrant` function. * @param beneficiary Recipient of the token purchase */ function buyTokens(address beneficiary) public nonReentrant payable { uint256 weiAmount = msg.value; _preValidatePurchase(beneficiary, weiAmount); // calculate token amount to be created uint256 tokens = _getTokenAmount(weiAmount); // update state _weiRaised = _weiRaised.add(weiAmount); _processPurchase(beneficiary, tokens); emit TokensPurchased(msg.sender, beneficiary, weiAmount, tokens); _updatePurchasingState(beneficiary, weiAmount); _forwardFunds(); _postValidatePurchase(beneficiary, weiAmount); } /** * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met. * Use `super` in contracts that inherit from Crowdsale to extend their validations. * Example from CappedCrowdsale.sol's _preValidatePurchase method: * super._preValidatePurchase(beneficiary, weiAmount); * require(weiRaised().add(weiAmount) <= cap); * @param beneficiary Address performing the token purchase * @param weiAmount Value in wei involved in the purchase */ function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view { require(beneficiary != address(0)); require(weiAmount != 0); } /** * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid * conditions are not met. * @param beneficiary Address performing the token purchase * @param weiAmount Value in wei involved in the purchase */ function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view { // solhint-disable-previous-line no-empty-blocks } /** * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends * its tokens. * @param beneficiary Address performing the token purchase * @param tokenAmount Number of tokens to be emitted */ function _deliverTokens(address beneficiary, uint256 tokenAmount) internal { _token.safeTransfer(beneficiary, tokenAmount); } /** * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send * tokens. * @param beneficiary Address receiving the tokens * @param tokenAmount Number of tokens to be purchased */ function _processPurchase(address beneficiary, uint256 tokenAmount) internal { _deliverTokens(beneficiary, tokenAmount); } /** * @dev Override for extensions that require an internal state to check for validity (current user contributions, * etc.) * @param beneficiary Address receiving the tokens * @param weiAmount Value in wei involved in the purchase */ function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal { // solhint-disable-previous-line no-empty-blocks } /** * @dev Override to extend the way in which ether is converted to tokens. * @param weiAmount Value in wei to be converted into tokens * @return Number of tokens that can be purchased with the specified _weiAmount */ function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) { return weiAmount.mul(_rate); } /** * @dev Determines how ETH is stored/forwarded on purchases. */ function _forwardFunds() internal { _wallet.transfer(msg.value); } }
0.4.21