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pragma solidity ^0.4.23; | |
import "https://github.com/ConsenSysMesh/openzeppelin-solidity/blob/master/contracts/math/SafeMath.sol"; | |
import "https://github.com/ConsenSysMesh/openzeppelin-solidity/blob/master/contracts/token/ERC20/ERC20.sol"; | |
contract Crowdsale { | |
using SafeMath for uint256; | |
// The token being sold | |
ERC20 public token; | |
// Address where funds are collected | |
address public wallet; | |
// How many token units a buyer gets per wei | |
uint256 public rate; | |
// Amount of wei raised | |
uint256 public 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 TokenPurchase( | |
address indexed purchaser, | |
address indexed beneficiary, | |
uint256 value, | |
uint256 amount | |
); | |
/** | |
* @param _rate Number of token units a buyer gets per wei | |
* @param _wallet Address where collected funds will be forwarded to | |
* @param _token Address of the token being sold | |
*/ | |
constructor(uint256 _rate, address _wallet, ERC20 _token) public { | |
require(_rate > 0); | |
require(_wallet != address(0)); | |
require(_token != address(0)); | |
rate = _rate; | |
wallet = _wallet; | |
token = _token; | |
} | |
// ----------------------------------------- | |
// Crowdsale external interface | |
// ----------------------------------------- | |
/** | |
* @dev fallback function ***DO NOT OVERRIDE*** | |
*/ | |
function () external payable { | |
buyTokens(msg.sender); | |
} | |
/** | |
* @dev low level token purchase ***DO NOT OVERRIDE*** | |
* @param _beneficiary Address performing the token purchase | |
*/ | |
function buyTokens(address _beneficiary) public 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 TokenPurchase( | |
msg.sender, | |
_beneficiary, | |
weiAmount, | |
tokens | |
); | |
_updatePurchasingState(_beneficiary, weiAmount); | |
_forwardFunds(); | |
_postValidatePurchase(_beneficiary, weiAmount); | |
} | |
// ----------------------------------------- | |
// Internal interface (extensible) | |
// ----------------------------------------- | |
/** | |
* @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met. Use super to concatenate validations. | |
* @param _beneficiary Address performing the token purchase | |
* @param _weiAmount Value in wei involved in the purchase | |
*/ | |
function _preValidatePurchase( | |
address _beneficiary, | |
uint256 _weiAmount | |
) | |
internal | |
{ | |
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 | |
{ | |
// optional override | |
} | |
/** | |
* @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.transfer(_beneficiary, _tokenAmount); | |
} | |
/** | |
* @dev Executed when a purchase has been validated and is ready to be executed. Not necessarily emits/sends 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 | |
{ | |
// optional override | |
} | |
/** | |
* @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); | |
} | |
} |
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