myth.log

myth.log

makoto@Makotos-MacBook-Air: [~/work/blockparty -  (coverage)] $ myth -x contracts/Conference.sol 



==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x05f203d9
PC address: 543
A possible integer overflow exists in the function `_function_0x05f203d9`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/GroupAdmin.sol:33

function revoke(address[] oldAdmins) public onlyOwner{
        for(uint i = 0; i < oldAdmins.length; i++){
            for (uint j = 0; j < admins.length; ++i) {
                if (admins[j] == oldAdmins[i]) {
                    admins[j] = admins[admins.length - 1];
                    admins.length--;
                    emit AdminRevoked(oldAdmins[i]);
                    break;
                }
            }
        }
    }

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x1e3c9352
PC address: 1206
A possible integer overflow exists in the function `_function_0x1e3c9352`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/GroupAdmin.sol:22

function grant(address[] newAdmins) public onlyOwner{
        for(uint i = 0; i < newAdmins.length; i++){
            admins.push(newAdmins[i]);
            emit AdminGranted(newAdmins[i]);
        }
    }

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x31ae450b
PC address: 1463
A possible integer overflow exists in the function `_function_0x31ae450b`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/GroupAdmin.sol:50

function getAdmins() view public returns(address[]){
        // todo: include owner;
        return admins;
    }

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: changeName(string)
PC address: 1639
A possible integer overflow exists in the function `changeName(string)`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/Conference.sol:236

function changeName(string _name) external onlyOwner noOneRegistered{
        name = _name;
    }

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: changeName(string)
PC address: 1645
A possible integer overflow exists in the function `changeName(string)`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/Conference.sol:236

function changeName(string _name) external onlyOwner noOneRegistered{
        name = _name;
    }

--------------------

==== Exception state ====
Type: Informational
Contract: Unknown
Function name: _function_0x05f203d9
PC address: 3200
A reachable exception (opcode 0xfe) has been detected. This can be caused by type errors, division by zero, out-of-bounds array access, or assert violations. This is acceptable in most situations. Note however that `assert()` should only be used to check invariants. Use `require()` for regular input checking. 
--------------------
In file: contracts/GroupAdmin.sol:36

oldAdmins[i]

--------------------

==== Exception state ====
Type: Informational
Contract: Unknown
Function name: _function_0x14bfd6d0
PC address: 4065
A reachable exception (opcode 0xfe) has been detected. This can be caused by type errors, division by zero, out-of-bounds array access, or assert violations. This is acceptable in most situations. Note however that `assert()` should only be used to check invariants. Use `require()` for regular input checking. 
--------------------
In file: contracts/GroupAdmin.sol:11

address[] public admins

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x1e3c9352
PC address: 4253
A possible integer overflow exists in the function `_function_0x1e3c9352`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/zeppelin/ownership/Ownable.sol:1

;


/**
 * @title 

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x31ae450b
PC address: 4759
A possible integer overflow exists in the function `_function_0x31ae450b`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/GroupAdmin.sol:52

return admins

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x31ae450b
PC address: 4761
A possible integer overflow exists in the function `_function_0x31ae450b`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/GroupAdmin.sol:52

return admins

--------------------

==== Transaction order dependence ====
Type: Warning
Contract: Unknown
Function name: withdraw()
PC address: 5265
A possible transaction order independence vulnerability exists in function withdraw(). The value or direction of the call statement is determined from a tainted storage location
--------------------
In file: contracts/Conference.sol:142

participant.addr.transfer(payoutAmount)

--------------------

==== Dependence on predictable environment variable ====
Type: Warning
Contract: Unknown
Function name: clear()
PC address: 5637
In the function `clear()` the following predictable state variables are used to determine Ether recipient:
- block.timestamp

--------------------
In file: contracts/Conference.sol:220

owner.transfer(leftOver)

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x05f203d9
PC address: 9232
A possible integer overflow exists in the function `_function_0x05f203d9`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/Conference.sol:6

contract Conference is Destructible, GroupAdmin {    
    string public name;
    uint256 public deposit;
    uint public limitOfParticipants;
    uint public registered;
    uint public attended;
    bool public ended;
    bool public cancelled;
    uint public endedAt;
    uint public coolingPeriod;
    uint256 public payoutAmount;
    string public encryption;

    mapping (address => Participant) public participants;
    mapping (uint => address) public participantsIndex;
    bool paid;

    struct Participant {
        string participantName;
        address addr;
        bool attended;
        bool paid;
    }

    event RegisterEvent(address addr, string participantName, string _encryption);
    event AttendEvent(address addr);
    event PaybackEvent(uint256 _payout);
    event WithdrawEvent(address addr, uint256 _payout);
    event CancelEvent();
    event ClearEvent(address addr, uint256 leftOver);

    /* Modifiers */
    modifier onlyActive {
        require(!ended);
        _;
    }

    modifier noOneRegistered {
        require(registered == 0);
        _;
    }

    modifier onlyEnded {
        require(ended);
        _;
    }

    /* Public functions */
    /**
     * @dev Construcotr.
     * @param _name The name of the event
     * @param _deposit The amount each participant deposits. The default is set to 0.02 Ether. The amount cannot be changed once deployed.
     * @param _limitOfParticipants The number of participant. The default is set to 20. The number can be changed by the owner of the event.
     * @param _coolingPeriod The period participants should withdraw their deposit after the event ends. After the cooling period, the event owner can claim the remining deposits.
     * @param _encryption A pubic key. The admin can use this public key to encrypt pariticipant username which is stored in event. The admin can later decrypt the name using his/her private key.
     */
    constructor (
        string _name,
        uint256 _deposit,
        uint _limitOfParticipants,
        uint _coolingPeriod,
        string _encryption
    ) public {
        if (bytes(_name).length != 0){
            name = _name;
        } else {
            name = 'Test';
        }

        if(_deposit != 0){
            deposit = _deposit;
        }else{
            deposit = 0.02 ether;
        }

        if (_limitOfParticipants != 0){
            limitOfParticipants = _limitOfParticipants;
        }else{
            limitOfParticipants = 20;
        }

        if (_coolingPeriod != 0) {
            coolingPeriod = _coolingPeriod;
        } else {
            coolingPeriod = 1 weeks;
        }

        if (bytes(_encryption).length != 0) {
            encryption = _encryption;
        }
    }

    /**
     * @dev Registers with twitter name and full user name (the user name is encrypted).
     * @param _participant The twitter address of the participant
     * @param _encrypted The encrypted participant name
     */
    function registerWithEncryption(string _participant, string _encrypted) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, _encrypted);
    }

    /**
     * @dev Registers with twitter name.
     * @param _participant The twitter address of the participant
     */
    function register(string _participant) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, '');
    }

    /**
     * @dev The internal function to register participant
     * @param _participant The twitter address of the participant
     */
    function registerInternal(string _participant) internal {
        require(msg.value == deposit);
        require(registered < limitOfParticipants);
        require(!isRegistered(msg.sender));

        registered++;
        participantsIndex[registered] = msg.sender;
        participants[msg.sender] = Participant(_participant, msg.sender, false, false);
    }

    /**
     * @dev Withdraws deposit after the event is over.
     */
    function withdraw() external onlyEnded{
        require(payoutAmount > 0);
        Participant participant = participants[msg.sender];
        require(participant.addr == msg.sender);
        require(cancelled || participant.attended);
        require(participant.paid == false);

        participant.paid = true;
        participant.addr.transfer(payoutAmount);
        emit WithdrawEvent(msg.sender, payoutAmount);
    }

    /* Constants */
    /**
     * @dev Returns total balance of the contract. This function can be deprecated when refactroing front end code.
     * @return The total balance of the contract.
     */
    function totalBalance() view public returns (uint256){
        return address(this).balance;
    }

    /**
     * @dev Returns true if the given user is registered.
     * @param _addr The address of a participant.
     * @return True if the address exists in the pariticipant list.
     */
    function isRegistered(address _addr) view public returns (bool){
        return participants[_addr].addr != address(0);
    }

    /**
     * @dev Returns true if the given user is attended.
     * @param _addr The address of a participant.
     * @return True if the user is marked as attended by admin.
     */
    function isAttended(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].attended;
    }

    /**
     * @dev Returns true if the given user has withdrawn his/her deposit.
     * @param _addr The address of a participant.
     * @return True if the attendee has withdrawn his/her deposit.
     */
    function isPaid(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].paid;
    }

    /**
     * @dev Show the payout amount each participant can withdraw.
     * @return The amount each participant can withdraw.
     */
    function payout() view public returns(uint256){
        if (attended == 0) return 0;
        return uint(totalBalance()) / uint(attended);
    }

    /* Admin only functions */

    /**
     * @dev Ends the event by owner
     */
    function payback() external onlyOwner onlyActive{
        payoutAmount = payout();
        ended = true;
        endedAt = now;
        emit PaybackEvent(payoutAmount);
    }

    /**
     * @dev Cancels the event by owner. When the event is canceled each participant can withdraw their deposit back.
     */
    function cancel() external onlyOwner onlyActive{
        payoutAmount = deposit;
        cancelled = true;
        ended = true;
        endedAt = now;
        emit CancelEvent();
    }

    /**
    * @dev The event owner transfer the outstanding deposits  if there are any unclaimed deposits after cooling period
    */
    function clear() external onlyOwner onlyEnded{
        require(now > endedAt + coolingPeriod);
        uint leftOver = totalBalance();
        owner.transfer(leftOver);
        emit ClearEvent(owner, leftOver);
    }

    /**
     * @dev Change the capacity of the event. The owner can change it until event is over.
     * @param _limitOfParticipants the number of the capacity of the event.
     */
    function setLimitOfParticipants(uint _limitOfParticipants) external onlyOwner onlyActive{
        limitOfParticipants = _limitOfParticipants;
    }

    /**
     * @dev Change the name of the event. The owner can change it as long as no one has registered yet.
     * @param _name the name of the event.
     */
    function changeName(string _name) external onlyOwner noOneRegistered{
        name = _name;
    }

    /**
     * @dev Mark participants as attended. The attendance cannot be undone.
     * @param _addresses The list of participant's address.
     */
    function attend(address[] _addresses) external onlyAdmin onlyActive{
        for( uint i = 0; i < _addresses.length; i++){
            address _addr = _addresses[i];
            require(isRegistered(_addr));
            require(!isAttended(_addr));
            emit AttendEvent(_addr);
            participants[_addr].attended = true;
            attended++;
        }
    }
}

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: _function_0x05f203d9
PC address: 9234
A possible integer overflow exists in the function `_function_0x05f203d9`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/Conference.sol:6

contract Conference is Destructible, GroupAdmin {    
    string public name;
    uint256 public deposit;
    uint public limitOfParticipants;
    uint public registered;
    uint public attended;
    bool public ended;
    bool public cancelled;
    uint public endedAt;
    uint public coolingPeriod;
    uint256 public payoutAmount;
    string public encryption;

    mapping (address => Participant) public participants;
    mapping (uint => address) public participantsIndex;
    bool paid;

    struct Participant {
        string participantName;
        address addr;
        bool attended;
        bool paid;
    }

    event RegisterEvent(address addr, string participantName, string _encryption);
    event AttendEvent(address addr);
    event PaybackEvent(uint256 _payout);
    event WithdrawEvent(address addr, uint256 _payout);
    event CancelEvent();
    event ClearEvent(address addr, uint256 leftOver);

    /* Modifiers */
    modifier onlyActive {
        require(!ended);
        _;
    }

    modifier noOneRegistered {
        require(registered == 0);
        _;
    }

    modifier onlyEnded {
        require(ended);
        _;
    }

    /* Public functions */
    /**
     * @dev Construcotr.
     * @param _name The name of the event
     * @param _deposit The amount each participant deposits. The default is set to 0.02 Ether. The amount cannot be changed once deployed.
     * @param _limitOfParticipants The number of participant. The default is set to 20. The number can be changed by the owner of the event.
     * @param _coolingPeriod The period participants should withdraw their deposit after the event ends. After the cooling period, the event owner can claim the remining deposits.
     * @param _encryption A pubic key. The admin can use this public key to encrypt pariticipant username which is stored in event. The admin can later decrypt the name using his/her private key.
     */
    constructor (
        string _name,
        uint256 _deposit,
        uint _limitOfParticipants,
        uint _coolingPeriod,
        string _encryption
    ) public {
        if (bytes(_name).length != 0){
            name = _name;
        } else {
            name = 'Test';
        }

        if(_deposit != 0){
            deposit = _deposit;
        }else{
            deposit = 0.02 ether;
        }

        if (_limitOfParticipants != 0){
            limitOfParticipants = _limitOfParticipants;
        }else{
            limitOfParticipants = 20;
        }

        if (_coolingPeriod != 0) {
            coolingPeriod = _coolingPeriod;
        } else {
            coolingPeriod = 1 weeks;
        }

        if (bytes(_encryption).length != 0) {
            encryption = _encryption;
        }
    }

    /**
     * @dev Registers with twitter name and full user name (the user name is encrypted).
     * @param _participant The twitter address of the participant
     * @param _encrypted The encrypted participant name
     */
    function registerWithEncryption(string _participant, string _encrypted) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, _encrypted);
    }

    /**
     * @dev Registers with twitter name.
     * @param _participant The twitter address of the participant
     */
    function register(string _participant) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, '');
    }

    /**
     * @dev The internal function to register participant
     * @param _participant The twitter address of the participant
     */
    function registerInternal(string _participant) internal {
        require(msg.value == deposit);
        require(registered < limitOfParticipants);
        require(!isRegistered(msg.sender));

        registered++;
        participantsIndex[registered] = msg.sender;
        participants[msg.sender] = Participant(_participant, msg.sender, false, false);
    }

    /**
     * @dev Withdraws deposit after the event is over.
     */
    function withdraw() external onlyEnded{
        require(payoutAmount > 0);
        Participant participant = participants[msg.sender];
        require(participant.addr == msg.sender);
        require(cancelled || participant.attended);
        require(participant.paid == false);

        participant.paid = true;
        participant.addr.transfer(payoutAmount);
        emit WithdrawEvent(msg.sender, payoutAmount);
    }

    /* Constants */
    /**
     * @dev Returns total balance of the contract. This function can be deprecated when refactroing front end code.
     * @return The total balance of the contract.
     */
    function totalBalance() view public returns (uint256){
        return address(this).balance;
    }

    /**
     * @dev Returns true if the given user is registered.
     * @param _addr The address of a participant.
     * @return True if the address exists in the pariticipant list.
     */
    function isRegistered(address _addr) view public returns (bool){
        return participants[_addr].addr != address(0);
    }

    /**
     * @dev Returns true if the given user is attended.
     * @param _addr The address of a participant.
     * @return True if the user is marked as attended by admin.
     */
    function isAttended(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].attended;
    }

    /**
     * @dev Returns true if the given user has withdrawn his/her deposit.
     * @param _addr The address of a participant.
     * @return True if the attendee has withdrawn his/her deposit.
     */
    function isPaid(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].paid;
    }

    /**
     * @dev Show the payout amount each participant can withdraw.
     * @return The amount each participant can withdraw.
     */
    function payout() view public returns(uint256){
        if (attended == 0) return 0;
        return uint(totalBalance()) / uint(attended);
    }

    /* Admin only functions */

    /**
     * @dev Ends the event by owner
     */
    function payback() external onlyOwner onlyActive{
        payoutAmount = payout();
        ended = true;
        endedAt = now;
        emit PaybackEvent(payoutAmount);
    }

    /**
     * @dev Cancels the event by owner. When the event is canceled each participant can withdraw their deposit back.
     */
    function cancel() external onlyOwner onlyActive{
        payoutAmount = deposit;
        cancelled = true;
        ended = true;
        endedAt = now;
        emit CancelEvent();
    }

    /**
    * @dev The event owner transfer the outstanding deposits  if there are any unclaimed deposits after cooling period
    */
    function clear() external onlyOwner onlyEnded{
        require(now > endedAt + coolingPeriod);
        uint leftOver = totalBalance();
        owner.transfer(leftOver);
        emit ClearEvent(owner, leftOver);
    }

    /**
     * @dev Change the capacity of the event. The owner can change it until event is over.
     * @param _limitOfParticipants the number of the capacity of the event.
     */
    function setLimitOfParticipants(uint _limitOfParticipants) external onlyOwner onlyActive{
        limitOfParticipants = _limitOfParticipants;
    }

    /**
     * @dev Change the name of the event. The owner can change it as long as no one has registered yet.
     * @param _name the name of the event.
     */
    function changeName(string _name) external onlyOwner noOneRegistered{
        name = _name;
    }

    /**
     * @dev Mark participants as attended. The attendance cannot be undone.
     * @param _addresses The list of participant's address.
     */
    function attend(address[] _addresses) external onlyAdmin onlyActive{
        for( uint i = 0; i < _addresses.length; i++){
            address _addr = _addresses[i];
            require(isRegistered(_addr));
            require(!isAttended(_addr));
            emit AttendEvent(_addr);
            participants[_addr].attended = true;
            attended++;
        }
    }
}

--------------------

==== Integer Overflow  ====
Type: Warning
Contract: Unknown
Function name: changeName(string)
PC address: 9318
A possible integer overflow exists in the function `changeName(string)`.
The addition or multiplication may result in a value higher than the maximum representable integer.
--------------------
In file: contracts/Conference.sol:6

contract Conference is Destructible, GroupAdmin {    
    string public name;
    uint256 public deposit;
    uint public limitOfParticipants;
    uint public registered;
    uint public attended;
    bool public ended;
    bool public cancelled;
    uint public endedAt;
    uint public coolingPeriod;
    uint256 public payoutAmount;
    string public encryption;

    mapping (address => Participant) public participants;
    mapping (uint => address) public participantsIndex;
    bool paid;

    struct Participant {
        string participantName;
        address addr;
        bool attended;
        bool paid;
    }

    event RegisterEvent(address addr, string participantName, string _encryption);
    event AttendEvent(address addr);
    event PaybackEvent(uint256 _payout);
    event WithdrawEvent(address addr, uint256 _payout);
    event CancelEvent();
    event ClearEvent(address addr, uint256 leftOver);

    /* Modifiers */
    modifier onlyActive {
        require(!ended);
        _;
    }

    modifier noOneRegistered {
        require(registered == 0);
        _;
    }

    modifier onlyEnded {
        require(ended);
        _;
    }

    /* Public functions */
    /**
     * @dev Construcotr.
     * @param _name The name of the event
     * @param _deposit The amount each participant deposits. The default is set to 0.02 Ether. The amount cannot be changed once deployed.
     * @param _limitOfParticipants The number of participant. The default is set to 20. The number can be changed by the owner of the event.
     * @param _coolingPeriod The period participants should withdraw their deposit after the event ends. After the cooling period, the event owner can claim the remining deposits.
     * @param _encryption A pubic key. The admin can use this public key to encrypt pariticipant username which is stored in event. The admin can later decrypt the name using his/her private key.
     */
    constructor (
        string _name,
        uint256 _deposit,
        uint _limitOfParticipants,
        uint _coolingPeriod,
        string _encryption
    ) public {
        if (bytes(_name).length != 0){
            name = _name;
        } else {
            name = 'Test';
        }

        if(_deposit != 0){
            deposit = _deposit;
        }else{
            deposit = 0.02 ether;
        }

        if (_limitOfParticipants != 0){
            limitOfParticipants = _limitOfParticipants;
        }else{
            limitOfParticipants = 20;
        }

        if (_coolingPeriod != 0) {
            coolingPeriod = _coolingPeriod;
        } else {
            coolingPeriod = 1 weeks;
        }

        if (bytes(_encryption).length != 0) {
            encryption = _encryption;
        }
    }

    /**
     * @dev Registers with twitter name and full user name (the user name is encrypted).
     * @param _participant The twitter address of the participant
     * @param _encrypted The encrypted participant name
     */
    function registerWithEncryption(string _participant, string _encrypted) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, _encrypted);
    }

    /**
     * @dev Registers with twitter name.
     * @param _participant The twitter address of the participant
     */
    function register(string _participant) external payable onlyActive{
        registerInternal(_participant);
        emit RegisterEvent(msg.sender, _participant, '');
    }

    /**
     * @dev The internal function to register participant
     * @param _participant The twitter address of the participant
     */
    function registerInternal(string _participant) internal {
        require(msg.value == deposit);
        require(registered < limitOfParticipants);
        require(!isRegistered(msg.sender));

        registered++;
        participantsIndex[registered] = msg.sender;
        participants[msg.sender] = Participant(_participant, msg.sender, false, false);
    }

    /**
     * @dev Withdraws deposit after the event is over.
     */
    function withdraw() external onlyEnded{
        require(payoutAmount > 0);
        Participant participant = participants[msg.sender];
        require(participant.addr == msg.sender);
        require(cancelled || participant.attended);
        require(participant.paid == false);

        participant.paid = true;
        participant.addr.transfer(payoutAmount);
        emit WithdrawEvent(msg.sender, payoutAmount);
    }

    /* Constants */
    /**
     * @dev Returns total balance of the contract. This function can be deprecated when refactroing front end code.
     * @return The total balance of the contract.
     */
    function totalBalance() view public returns (uint256){
        return address(this).balance;
    }

    /**
     * @dev Returns true if the given user is registered.
     * @param _addr The address of a participant.
     * @return True if the address exists in the pariticipant list.
     */
    function isRegistered(address _addr) view public returns (bool){
        return participants[_addr].addr != address(0);
    }

    /**
     * @dev Returns true if the given user is attended.
     * @param _addr The address of a participant.
     * @return True if the user is marked as attended by admin.
     */
    function isAttended(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].attended;
    }

    /**
     * @dev Returns true if the given user has withdrawn his/her deposit.
     * @param _addr The address of a participant.
     * @return True if the attendee has withdrawn his/her deposit.
     */
    function isPaid(address _addr) view public returns (bool){
        return isRegistered(_addr) && participants[_addr].paid;
    }

    /**
     * @dev Show the payout amount each participant can withdraw.
     * @return The amount each participant can withdraw.
     */
    function payout() view public returns(uint256){
        if (attended == 0) return 0;
        return uint(totalBalance()) / uint(attended);
    }

    /* Admin only functions */

    /**
     * @dev Ends the event by owner
     */
    function payback() external onlyOwner onlyActive{
        payoutAmount = payout();
        ended = true;
        endedAt = now;
        emit PaybackEvent(payoutAmount);
    }

    /**
     * @dev Cancels the event by owner. When the event is canceled each participant can withdraw their deposit back.
     */
    function cancel() external onlyOwner onlyActive{
        payoutAmount = deposit;
        cancelled = true;
        ended = true;
        endedAt = now;
        emit CancelEvent();
    }

    /**
    * @dev The event owner transfer the outstanding deposits  if there are any unclaimed deposits after cooling period
    */
    function clear() external onlyOwner onlyEnded{
        require(now > endedAt + coolingPeriod);
        uint leftOver = totalBalance();
        owner.transfer(leftOver);
        emit ClearEvent(owner, leftOver);
    }

    /**
     * @dev Change the capacity of the event. The owner can change it until event is over.
     * @param _limitOfParticipants the number of the capacity of the event.
     */
    function setLimitOfParticipants(uint _limitOfParticipants) external onlyOwner onlyActive{
        limitOfParticipants = _limitOfParticipants;
    }

    /**
     * @dev Change the name of the event. The owner can change it as long as no one has registered yet.
     * @param _name the name of the event.
     */
    function changeName(string _name) external onlyOwner noOneRegistered{
        name = _name;
    }

    /**
     * @dev Mark participants as attended. The attendance cannot be undone.
     * @param _addresses The list of participant's address.
     */
    function attend(address[] _addresses) external onlyAdmin onlyActive{
        for( uint i = 0; i < _addresses.length; i++){
            address _addr = _addresses[i];
            require(isRegistered(_addr));
            require(!isAttended(_addr));
            emit AttendEvent(_addr);
            participants[_addr].attended = true;
            attended++;
        }
    }
}

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