// Vulnerability label: time manipulation
pragma solidity ^0.4.21;
/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
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);
}
library DateTime {
        /*
         *  Date and Time utilities for ethereum contracts
         *
         */
        struct MyDateTime {
                uint16 year;
                uint8 month;
                uint8 day;
                uint8 hour;
                uint8 minute;
                uint8 second;
                uint8 weekday;
        }
        uint constant DAY_IN_SECONDS = 86400;
        uint constant YEAR_IN_SECONDS = 31536000;
        uint constant LEAP_YEAR_IN_SECONDS = 31622400;
        uint constant HOUR_IN_SECONDS = 3600;
        uint constant MINUTE_IN_SECONDS = 60;
        uint16 constant ORIGIN_YEAR = 1970;
        function isLeapYear(uint16 year) internal pure returns (bool) {
                if (year % 4 != 0) {
                        return false;
                }
                if (year % 100 != 0) {
                        return true;
                }
                if (year % 400 != 0) {
                        return false;
                }
                return true;
        }
        function leapYearsBefore(uint year) internal pure returns (uint) {
                year -= 1;
                return year / 4 - year / 100 + year / 400;
        }
        function getDaysInMonth(uint8 month, uint16 year) internal pure returns (uint8) {
                if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
                        return 31;
                }
                else if (month == 4 || month == 6 || month == 9 || month == 11) {
                        return 30;
                }
                else if (isLeapYear(year)) {
                        return 29;
                }
                else {
                        return 28;
                }
        }
        function parseTimestamp(uint timestamp) internal pure returns (MyDateTime dt) {
                uint secondsAccountedFor = 0;
                uint buf;
                uint8 i;
                // Year
                dt.year = getYear(timestamp);
                buf = leapYearsBefore(dt.year) - leapYearsBefore(ORIGIN_YEAR);
                secondsAccountedFor += LEAP_YEAR_IN_SECONDS * buf;
                secondsAccountedFor += YEAR_IN_SECONDS * (dt.year - ORIGIN_YEAR - buf);
                // Month
                uint secondsInMonth;
                for (i = 1; i <= 12; i++) {
                        secondsInMonth = DAY_IN_SECONDS * getDaysInMonth(i, dt.year);
                        if (secondsInMonth + secondsAccountedFor > timestamp) {
                                dt.month = i;
                                break;
                        }
                        secondsAccountedFor += secondsInMonth;
                }
                // Day
                for (i = 1; i <= getDaysInMonth(dt.month, dt.year); i++) {
                        if (DAY_IN_SECONDS + secondsAccountedFor > timestamp) {
                                dt.day = i;
                                break;
                        }
                        secondsAccountedFor += DAY_IN_SECONDS;
                }
                // Hour
                dt.hour = 0;//getHour(timestamp);
                // Minute
                dt.minute = 0;//getMinute(timestamp);
                // Second
                dt.second = 0;//getSecond(timestamp);
                // Day of week.
                dt.weekday = 0;//getWeekday(timestamp);
        }
        function getYear(uint timestamp) internal pure returns (uint16) {
                uint secondsAccountedFor = 0;
                uint16 year;
                uint numLeapYears;
                // Year
                year = uint16(ORIGIN_YEAR + timestamp / YEAR_IN_SECONDS);
                numLeapYears = leapYearsBefore(year) - leapYearsBefore(ORIGIN_YEAR);
                secondsAccountedFor += LEAP_YEAR_IN_SECONDS * numLeapYears;
                secondsAccountedFor += YEAR_IN_SECONDS * (year - ORIGIN_YEAR - numLeapYears);
                while (secondsAccountedFor > timestamp) {
                        if (isLeapYear(uint16(year - 1))) {
                                secondsAccountedFor -= LEAP_YEAR_IN_SECONDS;
                        }
                        else {
                                secondsAccountedFor -= YEAR_IN_SECONDS;
                        }
                        year -= 1;
                }
                return year;
        }
        function getMonth(uint timestamp) internal pure returns (uint8) {
                return parseTimestamp(timestamp).month;
        }
        function getDay(uint timestamp) internal pure returns (uint8) {
                return parseTimestamp(timestamp).day;
        }
        function getHour(uint timestamp) internal pure returns (uint8) {
                return uint8((timestamp / 60 / 60) % 24);
        }
        function getMinute(uint timestamp) internal pure returns (uint8) {
                return uint8((timestamp / 60) % 60);
        }
        function getSecond(uint timestamp) internal pure returns (uint8) {
                return uint8(timestamp % 60);
        }
        function toTimestamp(uint16 year, uint8 month, uint8 day) internal pure returns (uint timestamp) {
                return toTimestamp(year, month, day, 0, 0, 0);
        }
        function toTimestamp(uint16 year, uint8 month, uint8 day, uint8 hour, uint8 minute, uint8 second) internal pure returns (uint timestamp) {
                uint16 i;
                // Year
                for (i = ORIGIN_YEAR; i < year; i++) {
                        if (isLeapYear(i)) {
                                timestamp += LEAP_YEAR_IN_SECONDS;
                        }
                        else {
                                timestamp += YEAR_IN_SECONDS;
                        }
                }
                // Month
                uint8[12] memory monthDayCounts;
                monthDayCounts[0] = 31;
                if (isLeapYear(year)) {
                        monthDayCounts[1] = 29;
                }
                else {
                        monthDayCounts[1] = 28;
                }
                monthDayCounts[2] = 31;
                monthDayCounts[3] = 30;
                monthDayCounts[4] = 31;
                monthDayCounts[5] = 30;
                monthDayCounts[6] = 31;
                monthDayCounts[7] = 31;
                monthDayCounts[8] = 30;
                monthDayCounts[9] = 31;
                monthDayCounts[10] = 30;
                monthDayCounts[11] = 31;
                for (i = 1; i < month; i++) {
                        timestamp += DAY_IN_SECONDS * monthDayCounts[i - 1];
                }
                // Day
                timestamp += DAY_IN_SECONDS * (day - 1);
                // Hour
                timestamp += HOUR_IN_SECONDS * (hour);
                // Minute
                timestamp += MINUTE_IN_SECONDS * (minute);
                // Second
                timestamp += second;
                return timestamp;
        }
}
/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;
  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() 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 transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }
}
/**
 * @title Claimable
 * @dev Extension for the Ownable contract, where the ownership needs to be claimed.
 * This allows the new owner to accept the transfer.
 */
contract Claimable is Ownable {
  address public pendingOwner;
  /**
   * @dev Modifier throws if called by any account other than the pendingOwner.
   */
  modifier onlyPendingOwner() {
    require(msg.sender == pendingOwner);
    _;
  }
  /**
   * @dev Allows the current owner to set the pendingOwner address.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner public {
    pendingOwner = newOwner;
  }
  /**
   * @dev Allows the pendingOwner address to finalize the transfer.
   */
  function claimOwnership() onlyPendingOwner public {
    emit OwnershipTransferred(owner, pendingOwner);
    owner = pendingOwner;
    pendingOwner = address(0);
  }
}
/**
 * @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) {
    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;
  }
}
/**
 * @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 ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
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 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 Helps contracts guard agains reentrancy attacks.
 * @author Remco Bloemen <remco@2π.com>
 * @notice If you mark a function `nonReentrant`, you should also
 * mark it `external`.
 */
contract ReentrancyGuard {
  /**
   * @dev We use a single lock for the whole contract.
   */
  bool private reentrancyLock = false;
  /**
   * @dev Prevents a contract from calling itself, directly or indirectly.
   * @notice If you mark a function `nonReentrant`, you should also
   * mark it `external`. Calling one nonReentrant function from
   * another is not supported. Instead, you can implement a
   * `private` function doing the actual work, and a `external`
   * wrapper marked as `nonReentrant`.
   */
  modifier nonReentrant() {
    require(!reentrancyLock);
    reentrancyLock = true;
    _;
    reentrancyLock = false;
  }
}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract StandardBurnableToken is StandardToken {
    event Burn(address indexed burner, uint256 value);
    /**
     * @dev Burns a specific amount of tokens.
     * @param _value The amount of token to be burned.
     */
    function burn(uint256 _value) public returns (bool) {
        require(_value <= balances[msg.sender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure
        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply_ = totalSupply_.sub(_value);
        emit Burn(burner, _value);
        return true;
    }
}
contract Operational is Claimable {
    address public operator;
    function Operational(address _operator) public {
      operator = _operator;
    }
    modifier onlyOperator() {
      require(msg.sender == operator);
      _;
    }
    function transferOperator(address newOperator) public onlyOwner {
      require(newOperator != address(0));
      operator = newOperator;
    }
}
contract Frozenable is Operational, StandardBurnableToken, ReentrancyGuard {
    using DateTime for uint256;
    struct FrozenRecord {
        uint256 value;
        uint256 unfreezeIndex;
    }
    uint256 public frozenBalance;
    mapping (uint256 => FrozenRecord) public frozenRecords;
    uint256 mulDecimals = 100000000; // match decimals
    event SystemFreeze(address indexed owner, uint256 value, uint256 unfreezeIndex);
    event Unfreeze(address indexed owner, uint256 value, uint256 unfreezeTime);
    function Frozenable(address _operator) Operational(_operator) public {}
    // freeze system' balance
    function systemFreeze(uint256 _value, uint256 _unfreezeTime) internal {
        uint256 unfreezeIndex = uint256(_unfreezeTime.parseTimestamp().year) * 10000 + uint256(_unfreezeTime.parseTimestamp().month) * 100 + uint256(_unfreezeTime.parseTimestamp().day);
        balances[owner] = balances[owner].sub(_value);
        frozenRecords[unfreezeIndex] = FrozenRecord({value: _value, unfreezeIndex: unfreezeIndex});
        frozenBalance = frozenBalance.add(_value);
        emit SystemFreeze(owner, _value, _unfreezeTime);
    }
    // unfreeze frozen amount
    // everyone can call this function to unfreeze balance
    function unfreeze(uint256 timestamp) public returns (uint256 unfreezeAmount) {
        require(timestamp <= block.timestamp);
        uint256 unfreezeIndex = uint256(timestamp.parseTimestamp().year) * 10000 + uint256(timestamp.parseTimestamp().month) * 100 + uint256(timestamp.parseTimestamp().day);
        frozenBalance = frozenBalance.sub(frozenRecords[unfreezeIndex].value);
        balances[owner] = balances[owner].add(frozenRecords[unfreezeIndex].value);
        unfreezeAmount = frozenRecords[unfreezeIndex].value;
        emit Unfreeze(owner, unfreezeAmount, timestamp);
        frozenRecords[unfreezeIndex].value = 0;
        return unfreezeAmount;
    }
}
contract Releaseable is Frozenable {
    using SafeMath for uint;
    function Releaseable(
                    address _operator, uint256 _initialSupply
                ) Frozenable(_operator) public {
        balances[owner] = _initialSupply;
        totalSupply_ = _initialSupply;
    }
}
contract ERCoin is Releaseable {
    string public standard = '2018102500';
    string public name = 'ERCoin';
    string public symbol = 'ERC';
    uint8 public decimals = 8;
    function ERCoin() Releaseable(0xe8358AfA9Bc309c4A106dc41782340b91817BC64, mulDecimals.mul(1000000000)) public {}
}