pragma solidity ^0.4.18;




/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  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 c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}
contract Owned {
  event OwnerAddition(address indexed owner);

  event OwnerRemoval(address indexed owner);

  // owner address to enable admin functions
  mapping (address => bool) public isOwner;

  address[] public owners;

  address public operator;

  modifier onlyOwner {

    require(isOwner[msg.sender]);
    _;
  }

  modifier onlyOperator {
    require(msg.sender == operator);
    _;
  }

  function setOperator(address _operator) external onlyOwner {
    require(_operator != address(0));
    operator = _operator;
  }

  function removeOwner(address _owner) public onlyOwner {
    require(owners.length > 1);
    isOwner[_owner] = false;
    for (uint i = 0; i < owners.length - 1; i++) {
      if (owners[i] == _owner) {
        owners[i] = owners[SafeMath.sub(owners.length, 1)];
        break;
      }
    }
    owners.length = SafeMath.sub(owners.length, 1);
    OwnerRemoval(_owner);
  }

  function addOwner(address _owner) external onlyOwner {
    require(_owner != address(0));
    if(isOwner[_owner]) return;
    isOwner[_owner] = true;
    owners.push(_owner);
    OwnerAddition(_owner);
  }

  function setOwners(address[] _owners) internal {
    for (uint i = 0; i < _owners.length; i++) {
      require(_owners[i] != address(0));
      isOwner[_owners[i]] = true;
      OwnerAddition(_owners[i]);
    }
    owners = _owners;
  }

  function getOwners() public constant returns (address[])  {
    return owners;
  }

}

contract Validating {

  modifier validAddress(address _address) {
    require(_address != address(0x0));
    _;
  }

  modifier notZero(uint _number) {
    require(_number != 0);
    _;
  }

  modifier notEmpty(string _string) {
    require(bytes(_string).length != 0);
    _;
  }

}


contract Token {
    /* This is a slight change to the ERC20 base standard.
    function totalSupply() constant returns (uint256 supply);
    is replaced with:
    uint256 public totalSupply;
    This automatically creates a getter function for the totalSupply.
    This is moved to the base contract since public getter functions are not
    currently recognised as an implementation of the matching abstract
    function by the compiler.
    */
    /// total amount of tokens
    uint256 public totalSupply;

    /// @param _owner The address from which the balance will be retrieved
    /// @return The balance
    function balanceOf(address _owner) public constant returns (uint256 balance);

    /// @notice send `_value` token to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _value) public returns (bool success);

    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
    /// @param _from The address of the sender
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);

    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _value The amount of tokens to be approved for transfer
    /// @return Whether the approval was successful or not
    function approve(address _spender, uint256 _value) public returns (bool success);

    /// @param _owner The address of the account owning tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @return Amount of remaining tokens allowed to spent
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}

contract StandardToken is Token {

    function transfer(address _to, uint256 _value) public returns (bool success) {
        //Default assumes totalSupply can't be over max (2^256 - 1).
        //If your token leaves out totalSupply and can issue more tokens as time goes on, you need to check if it doesn't wrap.
        //Replace the if with this one instead.
        //require(balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]);
        require(balances[msg.sender] >= _value);
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        //same as above. Replace this line with the following if you want to protect against wrapping uints.
        //require(balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value > balances[_to]);
        require(balances[_from] >= _value && allowed[_from][msg.sender] >= _value);
        balances[_to] += _value;
        balances[_from] -= _value;
        allowed[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
    }

    function balanceOf(address _owner) public constant returns (uint256 balance) {
        return balances[_owner];
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
      return allowed[_owner][_spender];
    }

    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;
}



/**
  * @title FEE is an ERC20 token used to pay for trading on the exchange.
  * For deeper rational read https://leverj.io/whitepaper.pdf.
  * FEE tokens do not have limit. A new token can be generated by owner.
  */
contract Fee is Owned, Validating, StandardToken {

  /* This notifies clients about the amount burnt */
  event Burn(address indexed from, uint256 value);

  string public name;                   //fancy name: eg Simon Bucks
  uint8 public decimals;                //How many decimals to show. ie. There could 1000 base units with 3 decimals. Meaning 0.980 SBX = 980 base units. It's like comparing 1 wei to 1 ether.
  string public symbol;                 //An identifier: eg SBX
  uint256 public feeInCirculation;      //total fee in circulation
  string public version = 'F0.1';       //human 0.1 standard. Just an arbitrary versioning scheme.
  address public minter;

  modifier onlyMinter {
    require(msg.sender == minter);
    _;
  }

  /// @notice Constructor to set the owner, tokenName, decimals and symbol
  function Fee(
  address[] _owners,
  string _tokenName,
  uint8 _decimalUnits,
  string _tokenSymbol
  )
  public
  notEmpty(_tokenName)
  notEmpty(_tokenSymbol)
  {
    setOwners(_owners);
    name = _tokenName;
    decimals = _decimalUnits;
    symbol = _tokenSymbol;
  }

  /// @notice To set a new minter address
  /// @param _minter The address of the minter
  function setMinter(address _minter) external onlyOwner validAddress(_minter) {
    minter = _minter;
  }

  /// @notice To eliminate tokens and adjust the price of the FEE tokens
  /// @param _value Amount of tokens to delete
  function burnTokens(uint _value) public notZero(_value) {
    require(balances[msg.sender] >= _value);

    balances[msg.sender] = SafeMath.sub(balances[msg.sender], _value);
    feeInCirculation = SafeMath.sub(feeInCirculation, _value);
    Burn(msg.sender, _value);
  }

  /// @notice To send tokens to another user. New FEE tokens are generated when
  /// doing this process by the minter
  /// @param _to The receiver of the tokens
  /// @param _value The amount o
  function sendTokens(address _to, uint _value) public onlyMinter validAddress(_to) notZero(_value) {
    balances[_to] = SafeMath.add(balances[_to], _value);
    feeInCirculation = SafeMath.add(feeInCirculation, _value);
    Transfer(msg.sender, _to, _value);
  }
}