ETH Price: $2,135.69 (+7.64%)

Transaction Decoder

Block:
5794023 at Jun-15-2018 03:57:10 PM +UTC
Transaction Fee:
0.001463856 ETH $3.13
Gas Used:
91,491 Gas / 16 Gwei

Emitted Events:

161 OneledgerToken.Mint( to=[Sender] 0x638f275d520e22f59659120b28b14b547849213c, amount=7405969400000000000000 )
162 OneledgerToken.Transfer( from=0x0000000000000000000000000000000000000000, to=[Sender] 0x638f275d520e22f59659120b28b14b547849213c, value=7405969400000000000000 )
163 ICO.BuyTokens( weiAmount=795400000000000000, rate=9311, token=7405969400000000000000, beneficiary=[Sender] 0x638f275d520e22f59659120b28b14b547849213c )

Account State Difference:

  Address   Before After State Difference Code
0x2149CBdd...7Dc9C7d55
(OneLedger: Wallet)
2,273.735351089474708188 Eth2,274.530751089474708188 Eth0.7954
0x638f275d...47849213c
0.85424357000000002 Eth
Nonce: 64
0.05737971400000002 Eth
Nonce: 65
0.796863856
0x64A60493...Ae38EFCF0
0x72aa4083...b5e9fE32B
(OneLedger: Token Sale)
(MiningPoolHub: Old Address)
17,286.082422992983181561 Eth17,286.083886848983181561 Eth0.001463856

Execution Trace

ETH 0.7954 ICO.CALL( )
  • OneledgerToken.mint( _to=0x638f275d520e22F59659120b28b14B547849213c, _amount=7405969400000000000000 ) => ( True )
  • ETH 0.7954 OneLedger: Wallet.CALL( )
    File 1 of 2: ICO
    pragma solidity 0.4.24;
    
    
    /**
     * @title SafeMath
     * @dev Math operations with safety checks that throw on error
     */
    library SafeMath {
    
      /**
      * @dev Multiplies two numbers, throws on overflow.
      */
      function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        // Gas optimization: this is cheaper than asserting '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;
        }
    
        c = a * b;
        assert(c / a == b);
        return c;
      }
    
      /**
      * @dev Integer division of two numbers, truncating the quotient.
      */
      function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        // uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return a / b;
      }
    
      /**
      * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
      */
      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
      }
    
      /**
      * @dev Adds two numbers, throws on overflow.
      */
      function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
        assert(c >= a);
        return c;
      }
    }
    
    contract Ownable {
      address public owner;
    
    
      event OwnershipRenounced(address indexed previousOwner);
      event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
      );
    
    
      /**
       * @dev The Ownable constructor sets the original `owner` of the contract to the sender
       * account.
       */
      constructor() public {
        owner = msg.sender;
      }
    
      /**
       * @dev Throws if called by any account other than the owner.
       */
      modifier onlyOwner() {
        require(msg.sender == owner);
        _;
      }
    
      /**
       * @dev Allows the current owner to relinquish control of the contract.
       */
      function renounceOwnership() public onlyOwner {
        emit OwnershipRenounced(owner);
        owner = address(0);
      }
    
      /**
       * @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 {
        _transferOwnership(_newOwner);
      }
    
      /**
       * @dev Transfers control of the contract to a newOwner.
       * @param _newOwner The address to transfer ownership to.
       */
      function _transferOwnership(address _newOwner) internal {
        require(_newOwner != address(0));
        emit OwnershipTransferred(owner, _newOwner);
        owner = _newOwner;
      }
    }
    
    contract ERC20Basic {
      function totalSupply() public view returns (uint256);
      function balanceOf(address who) public view returns (uint256);
      function transfer(address to, uint256 value) public returns (bool);
      event Transfer(address indexed from, address indexed to, uint256 value);
    }
    
    contract ERC20 is ERC20Basic {
      function allowance(address owner, address spender)
        public view returns (uint256);
    
      function transferFrom(address from, address to, uint256 value)
        public returns (bool);
    
      function approve(address spender, uint256 value) public returns (bool);
      event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
      );
    }
    
    /**
     * @title Basic token
     * @dev Basic version of StandardToken, with no allowances.
     */
    contract BasicToken is ERC20Basic {
      using SafeMath for uint256;
    
      mapping(address => uint256) balances;
    
      uint256 totalSupply_;
    
      /**
      * @dev total number of tokens in existence
      */
      function totalSupply() public view returns (uint256) {
        return totalSupply_;
      }
    
      /**
      * @dev transfer token for a specified address
      * @param _to The address to transfer to.
      * @param _value The amount to be transferred.
      */
      function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
    
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
      }
    
      /**
      * @dev Gets the balance of the specified address.
      * @param _owner The address to query the the balance of.
      * @return An uint256 representing the amount owned by the passed address.
      */
      function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
      }
    
    }
    
    /**
     * @title Standard ERC20 token
     *
     * @dev Implementation of the basic standard token.
     * @dev https://github.com/ethereum/EIPs/issues/20
     * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
     */
    contract StandardToken is ERC20, BasicToken {
    
      mapping (address => mapping (address => uint256)) internal allowed;
    
    
      /**
       * @dev Transfer tokens from one address to another
       * @param _from address The address which you want to send tokens from
       * @param _to address The address which you want to transfer to
       * @param _value uint256 the amount of tokens to be transferred
       */
      function transferFrom(
        address _from,
        address _to,
        uint256 _value
      )
        public
        returns (bool)
      {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
    
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
      }
    
      /**
       * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
       *
       * 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
       * @param _spender The address which will spend the funds.
       * @param _value The amount of tokens to be spent.
       */
      function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
      }
    
      /**
       * @dev Function to check the amount of tokens that an owner allowed to a spender.
       * @param _owner address The address which owns the funds.
       * @param _spender address The address which will spend the funds.
       * @return A uint256 specifying the amount of tokens still available for the spender.
       */
      function allowance(
        address _owner,
        address _spender
       )
        public
        view
        returns (uint256)
      {
        return allowed[_owner][_spender];
      }
    
      /**
       * @dev Increase the amount of tokens that an owner allowed to a spender.
       *
       * approve should be called when allowed[_spender] == 0. To increment
       * allowed value is better to use this function to avoid 2 calls (and wait until
       * the first transaction is mined)
       * From MonolithDAO Token.sol
       * @param _spender The address which will spend the funds.
       * @param _addedValue The amount of tokens to increase the allowance by.
       */
      function increaseApproval(
        address _spender,
        uint _addedValue
      )
        public
        returns (bool)
      {
        allowed[msg.sender][_spender] = (
          allowed[msg.sender][_spender].add(_addedValue));
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
      }
    
      /**
       * @dev Decrease the amount of tokens that an owner allowed to a spender.
       *
       * approve should be called when allowed[_spender] == 0. To decrement
       * allowed value is better to use this function to avoid 2 calls (and wait until
       * the first transaction is mined)
       * From MonolithDAO Token.sol
       * @param _spender The address which will spend the funds.
       * @param _subtractedValue The amount of tokens to decrease the allowance by.
       */
      function decreaseApproval(
        address _spender,
        uint _subtractedValue
      )
        public
        returns (bool)
      {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
          allowed[msg.sender][_spender] = 0;
        } else {
          allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
      }
    
    }
    
    /**
     * @title Mintable token
     * @dev Simple ERC20 Token example, with mintable token creation
     * @dev Issue: * https://github.com/OpenZeppelin/openzeppelin-solidity/issues/120
     * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
     */
    contract MintableToken is StandardToken, Ownable {
      event Mint(address indexed to, uint256 amount);
      event MintFinished();
    
      bool public mintingFinished = false;
    
    
      modifier canMint() {
        require(!mintingFinished);
        _;
      }
    
      modifier hasMintPermission() {
        require(msg.sender == owner);
        _;
      }
    
      /**
       * @dev Function to mint tokens
       * @param _to The address that will receive the minted tokens.
       * @param _amount The amount of tokens to mint.
       * @return A boolean that indicates if the operation was successful.
       */
      function mint(
        address _to,
        uint256 _amount
      )
        hasMintPermission
        canMint
        public
        returns (bool)
      {
        totalSupply_ = totalSupply_.add(_amount);
        balances[_to] = balances[_to].add(_amount);
        emit Mint(_to, _amount);
        emit Transfer(address(0), _to, _amount);
        return true;
      }
    
      /**
       * @dev Function to stop minting new tokens.
       * @return True if the operation was successful.
       */
      function finishMinting() onlyOwner canMint public returns (bool) {
        mintingFinished = true;
        emit MintFinished();
        return true;
      }
    }
    
    
    /**
    * @title OneledgerToken
    * @dev this is the oneledger token
    */
    contract OneledgerToken is MintableToken {
        using SafeMath for uint256;
    
        string public name = "Oneledger Token";
        string public symbol = "OLT";
        uint8 public decimals = 18;
        bool public active = false;
        /**
         * @dev restrict function to be callable when token is active
         */
        modifier activated() {
            require(active == true);
            _;
        }
    
        /**
         * @dev activate token transfers
         */
        function activate() public onlyOwner {
            active = true;
        }
    
        /**
         * @dev transfer    ERC20 standard transfer wrapped with `activated` modifier
         */
        function transfer(address to, uint256 value) public activated returns (bool) {
            return super.transfer(to, value);
        }
    
        /**
         * @dev transfer    ERC20 standard transferFrom wrapped with `activated` modifier
         */
        function transferFrom(address from, address to, uint256 value) public activated returns (bool) {
            return super.transferFrom(from, to, value);
        }
    }
    
    contract ICO is Ownable {
        using SafeMath for uint256;
    
        struct WhiteListRecord {
            uint256 offeredWei;
            uint256 lastPurchasedTimestamp;
        }
    
        OneledgerToken public token;
        address public wallet; // Address where funds are collected
        uint256 public rate;   // How many token units a buyer gets per eth
        mapping (address => WhiteListRecord) public whiteList;
        uint256 public initialTime;
        bool public saleClosed;
        uint256 public weiCap;
        uint256 public weiRaised;
    
        uint256 public TOTAL_TOKEN_SUPPLY = 1000000000 * (10 ** 18);
    
        event BuyTokens(uint256 weiAmount, uint256 rate, uint256 token, address beneficiary);
        event UpdateRate(uint256 rate);
        event UpdateWeiCap(uint256 weiCap);
        /**
        * @dev constructor
        */
        constructor(address _wallet, uint256 _rate, uint256 _startDate, uint256 _weiCap) public {
            require(_rate > 0);
            require(_wallet != address(0));
            require(_weiCap.mul(_rate) <= TOTAL_TOKEN_SUPPLY);
    
            wallet = _wallet;
            rate = _rate;
            initialTime = _startDate;
            saleClosed = false;
            weiCap = _weiCap;
            weiRaised = 0;
    
            token = new OneledgerToken();
        }
    
        /**
         * @dev fallback function ***DO NOT OVERRIDE***
         */
        function() external payable {
            buyTokens();
        }
    
        /**
         * @dev update the rate
         */
        function updateRate(uint256 rate_) public onlyOwner {
          require(now <= initialTime);
          rate = rate_;
          emit UpdateRate(rate);
        }
    
        /**
         * @dev update the weiCap
         */
        function updateWeiCap(uint256 weiCap_) public onlyOwner {
          require(now <= initialTime);
          weiCap = weiCap_;
          emit UpdateWeiCap(weiCap_);
        }
    
        /**
         * @dev buy tokens
         */
        function buyTokens() public payable {
            validatePurchase(msg.value);
            uint256 tokenToBuy = msg.value.mul(rate);
            whiteList[msg.sender].lastPurchasedTimestamp = now;
            weiRaised = weiRaised.add(msg.value);
            token.mint(msg.sender, tokenToBuy);
            wallet.transfer(msg.value);
            emit BuyTokens(msg.value, rate, tokenToBuy, msg.sender);
        }
    
        /**
        * @dev add to white list
        * param addresses the list of address added to white list
        * param weiPerContributor the wei can be transfer per contributor
        * param capWei for the user in this list
        */
        function addToWhiteList(address[] addresses, uint256 weiPerContributor) public onlyOwner {
            for (uint32 i = 0; i < addresses.length; i++) {
                whiteList[addresses[i]] = WhiteListRecord(weiPerContributor, 0);
            }
        }
    
        /**
         * @dev mint token to new address, either contract or a wallet
         * param OneledgerTokenVesting vesting contract
         * param uint256 total token number to mint
        */
        function mintToken(address target, uint256 tokenToMint) public onlyOwner {
          token.mint(target, tokenToMint);
        }
    
        /**
         * @dev close the ICO
         */
        function closeSale() public onlyOwner {
            saleClosed = true;
            if (TOTAL_TOKEN_SUPPLY > token.totalSupply()) {
              token.mint(owner, TOTAL_TOKEN_SUPPLY.sub(token.totalSupply()));
            }
            token.finishMinting();
            token.transferOwnership(owner);
        }
    
        function validatePurchase(uint256 weiPaid) internal view{
            require(!saleClosed);
            require(initialTime <= now);
            require(whiteList[msg.sender].offeredWei > 0);
            require(weiPaid <= weiCap.sub(weiRaised));
            // can only purchase once every 24 hours
            require(now.sub(whiteList[msg.sender].lastPurchasedTimestamp) > 24 hours);
            uint256 elapsedTime = now.sub(initialTime);
            // check day 1 buy limit
            require(elapsedTime > 24 hours || msg.value <= whiteList[msg.sender].offeredWei);
            // check day 2 buy limit
            require(elapsedTime > 48 hours || msg.value <= whiteList[msg.sender].offeredWei.mul(2));
        }
    }
    
    
    contract OneledgerTokenVesting is Ownable{
        using SafeMath for uint256;
    
        event Released(uint256 amount);
    
        // beneficiary of tokens after they are released
        address public beneficiary;
    
        uint256 public startFrom;
        uint256 public period;
        uint256 public tokensReleasedPerPeriod;
    
        uint256 public elapsedPeriods;
    
        OneledgerToken private token;
    
        /**
         * @dev Creates a vesting contract for OneledgerToken
         * @param _beneficiary address of the beneficiary to whom vested tokens are transferred
         * @param _startFrom Datetime when the vesting will begin
         * @param _period The preiod to release the token
         * @param _tokensReleasedPerPeriod the token to release per period
         */
        constructor(
            address _beneficiary,
            uint256 _startFrom,
            uint256 _period,
            uint256 _tokensReleasedPerPeriod,
            OneledgerToken _token
        ) public {
            require(_beneficiary != address(0));
            require(_startFrom >= now);
    
            beneficiary = _beneficiary;
            startFrom = _startFrom;
            period = _period;
            tokensReleasedPerPeriod = _tokensReleasedPerPeriod;
            elapsedPeriods = 0;
            token = _token;
        }
    
        /**
         *  @dev getToken this may be more convinience for user
         *        to check if their vesting contract is binded with a right token
         * return OneledgerToken
         */
         function getToken() public view returns(OneledgerToken) {
           return token;
         }
    
        /**
         * @dev release
         * param _token Oneledgertoken that will be released to beneficiary
         */
        function release() public {
            require(msg.sender == owner || msg.sender == beneficiary);
            require(token.balanceOf(this) >= 0 && now >= startFrom);
            uint256 elapsedTime = now.sub(startFrom);
            uint256 periodsInCurrentRelease = elapsedTime.div(period).sub(elapsedPeriods);
            uint256 tokensReadyToRelease = periodsInCurrentRelease.mul(tokensReleasedPerPeriod);
            uint256 amountToTransfer = tokensReadyToRelease > token.balanceOf(this) ? token.balanceOf(this) : tokensReadyToRelease;
            require(amountToTransfer > 0);
            elapsedPeriods = elapsedPeriods.add(periodsInCurrentRelease);
            token.transfer(beneficiary, amountToTransfer);
            emit Released(amountToTransfer);
        }
    }

    File 2 of 2: OneledgerToken
    pragma solidity 0.4.24;
    
    
    /**
     * @title SafeMath
     * @dev Math operations with safety checks that throw on error
     */
    library SafeMath {
    
      /**
      * @dev Multiplies two numbers, throws on overflow.
      */
      function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        // Gas optimization: this is cheaper than asserting '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;
        }
    
        c = a * b;
        assert(c / a == b);
        return c;
      }
    
      /**
      * @dev Integer division of two numbers, truncating the quotient.
      */
      function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        // uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return a / b;
      }
    
      /**
      * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
      */
      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
      }
    
      /**
      * @dev Adds two numbers, throws on overflow.
      */
      function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
        assert(c >= a);
        return c;
      }
    }
    
    contract Ownable {
      address public owner;
    
    
      event OwnershipRenounced(address indexed previousOwner);
      event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
      );
    
    
      /**
       * @dev The Ownable constructor sets the original `owner` of the contract to the sender
       * account.
       */
      constructor() public {
        owner = msg.sender;
      }
    
      /**
       * @dev Throws if called by any account other than the owner.
       */
      modifier onlyOwner() {
        require(msg.sender == owner);
        _;
      }
    
      /**
       * @dev Allows the current owner to relinquish control of the contract.
       */
      function renounceOwnership() public onlyOwner {
        emit OwnershipRenounced(owner);
        owner = address(0);
      }
    
      /**
       * @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 {
        _transferOwnership(_newOwner);
      }
    
      /**
       * @dev Transfers control of the contract to a newOwner.
       * @param _newOwner The address to transfer ownership to.
       */
      function _transferOwnership(address _newOwner) internal {
        require(_newOwner != address(0));
        emit OwnershipTransferred(owner, _newOwner);
        owner = _newOwner;
      }
    }
    
    contract ERC20Basic {
      function totalSupply() public view returns (uint256);
      function balanceOf(address who) public view returns (uint256);
      function transfer(address to, uint256 value) public returns (bool);
      event Transfer(address indexed from, address indexed to, uint256 value);
    }
    
    contract ERC20 is ERC20Basic {
      function allowance(address owner, address spender)
        public view returns (uint256);
    
      function transferFrom(address from, address to, uint256 value)
        public returns (bool);
    
      function approve(address spender, uint256 value) public returns (bool);
      event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
      );
    }
    
    /**
     * @title Basic token
     * @dev Basic version of StandardToken, with no allowances.
     */
    contract BasicToken is ERC20Basic {
      using SafeMath for uint256;
    
      mapping(address => uint256) balances;
    
      uint256 totalSupply_;
    
      /**
      * @dev total number of tokens in existence
      */
      function totalSupply() public view returns (uint256) {
        return totalSupply_;
      }
    
      /**
      * @dev transfer token for a specified address
      * @param _to The address to transfer to.
      * @param _value The amount to be transferred.
      */
      function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
    
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
      }
    
      /**
      * @dev Gets the balance of the specified address.
      * @param _owner The address to query the the balance of.
      * @return An uint256 representing the amount owned by the passed address.
      */
      function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
      }
    
    }
    
    /**
     * @title Standard ERC20 token
     *
     * @dev Implementation of the basic standard token.
     * @dev https://github.com/ethereum/EIPs/issues/20
     * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
     */
    contract StandardToken is ERC20, BasicToken {
    
      mapping (address => mapping (address => uint256)) internal allowed;
    
    
      /**
       * @dev Transfer tokens from one address to another
       * @param _from address The address which you want to send tokens from
       * @param _to address The address which you want to transfer to
       * @param _value uint256 the amount of tokens to be transferred
       */
      function transferFrom(
        address _from,
        address _to,
        uint256 _value
      )
        public
        returns (bool)
      {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
    
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
      }
    
      /**
       * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
       *
       * 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
       * @param _spender The address which will spend the funds.
       * @param _value The amount of tokens to be spent.
       */
      function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
      }
    
      /**
       * @dev Function to check the amount of tokens that an owner allowed to a spender.
       * @param _owner address The address which owns the funds.
       * @param _spender address The address which will spend the funds.
       * @return A uint256 specifying the amount of tokens still available for the spender.
       */
      function allowance(
        address _owner,
        address _spender
       )
        public
        view
        returns (uint256)
      {
        return allowed[_owner][_spender];
      }
    
      /**
       * @dev Increase the amount of tokens that an owner allowed to a spender.
       *
       * approve should be called when allowed[_spender] == 0. To increment
       * allowed value is better to use this function to avoid 2 calls (and wait until
       * the first transaction is mined)
       * From MonolithDAO Token.sol
       * @param _spender The address which will spend the funds.
       * @param _addedValue The amount of tokens to increase the allowance by.
       */
      function increaseApproval(
        address _spender,
        uint _addedValue
      )
        public
        returns (bool)
      {
        allowed[msg.sender][_spender] = (
          allowed[msg.sender][_spender].add(_addedValue));
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
      }
    
      /**
       * @dev Decrease the amount of tokens that an owner allowed to a spender.
       *
       * approve should be called when allowed[_spender] == 0. To decrement
       * allowed value is better to use this function to avoid 2 calls (and wait until
       * the first transaction is mined)
       * From MonolithDAO Token.sol
       * @param _spender The address which will spend the funds.
       * @param _subtractedValue The amount of tokens to decrease the allowance by.
       */
      function decreaseApproval(
        address _spender,
        uint _subtractedValue
      )
        public
        returns (bool)
      {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
          allowed[msg.sender][_spender] = 0;
        } else {
          allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
      }
    
    }
    
    /**
     * @title Mintable token
     * @dev Simple ERC20 Token example, with mintable token creation
     * @dev Issue: * https://github.com/OpenZeppelin/openzeppelin-solidity/issues/120
     * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
     */
    contract MintableToken is StandardToken, Ownable {
      event Mint(address indexed to, uint256 amount);
      event MintFinished();
    
      bool public mintingFinished = false;
    
    
      modifier canMint() {
        require(!mintingFinished);
        _;
      }
    
      modifier hasMintPermission() {
        require(msg.sender == owner);
        _;
      }
    
      /**
       * @dev Function to mint tokens
       * @param _to The address that will receive the minted tokens.
       * @param _amount The amount of tokens to mint.
       * @return A boolean that indicates if the operation was successful.
       */
      function mint(
        address _to,
        uint256 _amount
      )
        hasMintPermission
        canMint
        public
        returns (bool)
      {
        totalSupply_ = totalSupply_.add(_amount);
        balances[_to] = balances[_to].add(_amount);
        emit Mint(_to, _amount);
        emit Transfer(address(0), _to, _amount);
        return true;
      }
    
      /**
       * @dev Function to stop minting new tokens.
       * @return True if the operation was successful.
       */
      function finishMinting() onlyOwner canMint public returns (bool) {
        mintingFinished = true;
        emit MintFinished();
        return true;
      }
    }
    
    
    /**
    * @title OneledgerToken
    * @dev this is the oneledger token
    */
    contract OneledgerToken is MintableToken {
        using SafeMath for uint256;
    
        string public name = "Oneledger Token";
        string public symbol = "OLT";
        uint8 public decimals = 18;
        bool public active = false;
        /**
         * @dev restrict function to be callable when token is active
         */
        modifier activated() {
            require(active == true);
            _;
        }
    
        /**
         * @dev activate token transfers
         */
        function activate() public onlyOwner {
            active = true;
        }
    
        /**
         * @dev transfer    ERC20 standard transfer wrapped with `activated` modifier
         */
        function transfer(address to, uint256 value) public activated returns (bool) {
            return super.transfer(to, value);
        }
    
        /**
         * @dev transfer    ERC20 standard transferFrom wrapped with `activated` modifier
         */
        function transferFrom(address from, address to, uint256 value) public activated returns (bool) {
            return super.transferFrom(from, to, value);
        }
    }
    
    contract ICO is Ownable {
        using SafeMath for uint256;
    
        struct WhiteListRecord {
            uint256 offeredWei;
            uint256 lastPurchasedTimestamp;
        }
    
        OneledgerToken public token;
        address public wallet; // Address where funds are collected
        uint256 public rate;   // How many token units a buyer gets per eth
        mapping (address => WhiteListRecord) public whiteList;
        uint256 public initialTime;
        bool public saleClosed;
        uint256 public weiCap;
        uint256 public weiRaised;
    
        uint256 public TOTAL_TOKEN_SUPPLY = 1000000000 * (10 ** 18);
    
        event BuyTokens(uint256 weiAmount, uint256 rate, uint256 token, address beneficiary);
        event UpdateRate(uint256 rate);
        event UpdateWeiCap(uint256 weiCap);
        /**
        * @dev constructor
        */
        constructor(address _wallet, uint256 _rate, uint256 _startDate, uint256 _weiCap) public {
            require(_rate > 0);
            require(_wallet != address(0));
            require(_weiCap.mul(_rate) <= TOTAL_TOKEN_SUPPLY);
    
            wallet = _wallet;
            rate = _rate;
            initialTime = _startDate;
            saleClosed = false;
            weiCap = _weiCap;
            weiRaised = 0;
    
            token = new OneledgerToken();
        }
    
        /**
         * @dev fallback function ***DO NOT OVERRIDE***
         */
        function() external payable {
            buyTokens();
        }
    
        /**
         * @dev update the rate
         */
        function updateRate(uint256 rate_) public onlyOwner {
          require(now <= initialTime);
          rate = rate_;
          emit UpdateRate(rate);
        }
    
        /**
         * @dev update the weiCap
         */
        function updateWeiCap(uint256 weiCap_) public onlyOwner {
          require(now <= initialTime);
          weiCap = weiCap_;
          emit UpdateWeiCap(weiCap_);
        }
    
        /**
         * @dev buy tokens
         */
        function buyTokens() public payable {
            validatePurchase(msg.value);
            uint256 tokenToBuy = msg.value.mul(rate);
            whiteList[msg.sender].lastPurchasedTimestamp = now;
            weiRaised = weiRaised.add(msg.value);
            token.mint(msg.sender, tokenToBuy);
            wallet.transfer(msg.value);
            emit BuyTokens(msg.value, rate, tokenToBuy, msg.sender);
        }
    
        /**
        * @dev add to white list
        * param addresses the list of address added to white list
        * param weiPerContributor the wei can be transfer per contributor
        * param capWei for the user in this list
        */
        function addToWhiteList(address[] addresses, uint256 weiPerContributor) public onlyOwner {
            for (uint32 i = 0; i < addresses.length; i++) {
                whiteList[addresses[i]] = WhiteListRecord(weiPerContributor, 0);
            }
        }
    
        /**
         * @dev mint token to new address, either contract or a wallet
         * param OneledgerTokenVesting vesting contract
         * param uint256 total token number to mint
        */
        function mintToken(address target, uint256 tokenToMint) public onlyOwner {
          token.mint(target, tokenToMint);
        }
    
        /**
         * @dev close the ICO
         */
        function closeSale() public onlyOwner {
            saleClosed = true;
            if (TOTAL_TOKEN_SUPPLY > token.totalSupply()) {
              token.mint(owner, TOTAL_TOKEN_SUPPLY.sub(token.totalSupply()));
            }
            token.finishMinting();
            token.transferOwnership(owner);
        }
    
        function validatePurchase(uint256 weiPaid) internal view{
            require(!saleClosed);
            require(initialTime <= now);
            require(whiteList[msg.sender].offeredWei > 0);
            require(weiPaid <= weiCap.sub(weiRaised));
            // can only purchase once every 24 hours
            require(now.sub(whiteList[msg.sender].lastPurchasedTimestamp) > 24 hours);
            uint256 elapsedTime = now.sub(initialTime);
            // check day 1 buy limit
            require(elapsedTime > 24 hours || msg.value <= whiteList[msg.sender].offeredWei);
            // check day 2 buy limit
            require(elapsedTime > 48 hours || msg.value <= whiteList[msg.sender].offeredWei.mul(2));
        }
    }
    
    
    contract OneledgerTokenVesting is Ownable{
        using SafeMath for uint256;
    
        event Released(uint256 amount);
    
        // beneficiary of tokens after they are released
        address public beneficiary;
    
        uint256 public startFrom;
        uint256 public period;
        uint256 public tokensReleasedPerPeriod;
    
        uint256 public elapsedPeriods;
    
        OneledgerToken private token;
    
        /**
         * @dev Creates a vesting contract for OneledgerToken
         * @param _beneficiary address of the beneficiary to whom vested tokens are transferred
         * @param _startFrom Datetime when the vesting will begin
         * @param _period The preiod to release the token
         * @param _tokensReleasedPerPeriod the token to release per period
         */
        constructor(
            address _beneficiary,
            uint256 _startFrom,
            uint256 _period,
            uint256 _tokensReleasedPerPeriod,
            OneledgerToken _token
        ) public {
            require(_beneficiary != address(0));
            require(_startFrom >= now);
    
            beneficiary = _beneficiary;
            startFrom = _startFrom;
            period = _period;
            tokensReleasedPerPeriod = _tokensReleasedPerPeriod;
            elapsedPeriods = 0;
            token = _token;
        }
    
        /**
         *  @dev getToken this may be more convinience for user
         *        to check if their vesting contract is binded with a right token
         * return OneledgerToken
         */
         function getToken() public view returns(OneledgerToken) {
           return token;
         }
    
        /**
         * @dev release
         * param _token Oneledgertoken that will be released to beneficiary
         */
        function release() public {
            require(msg.sender == owner || msg.sender == beneficiary);
            require(token.balanceOf(this) >= 0 && now >= startFrom);
            uint256 elapsedTime = now.sub(startFrom);
            uint256 periodsInCurrentRelease = elapsedTime.div(period).sub(elapsedPeriods);
            uint256 tokensReadyToRelease = periodsInCurrentRelease.mul(tokensReleasedPerPeriod);
            uint256 amountToTransfer = tokensReadyToRelease > token.balanceOf(this) ? token.balanceOf(this) : tokensReadyToRelease;
            require(amountToTransfer > 0);
            elapsedPeriods = elapsedPeriods.add(periodsInCurrentRelease);
            token.transfer(beneficiary, amountToTransfer);
            emit Released(amountToTransfer);
        }
    }