pragma solidity ^0.4.23;

library SafeMath {

    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;
    }

    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;
    }

    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 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.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  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 Pausable is Ownable {

    event Pause();
    event Unpause();

    bool public paused = false;

    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    modifier whenPaused() {
        require(paused);
        _;
    }

    function pause() onlyOwner whenNotPaused public {
        paused = true;
        emit Pause();
    }

    function unpause() onlyOwner whenPaused public {
        paused = false;
        emit Unpause();
    }
}

contract ERC20Basic {
    function totalSupply() public view returns (uint256);
    // function totalSupply() view returns (uint256 totalSupply) EIP
    function balanceOf(address who) public view returns (uint256);
    // function balanceOf(address _owner) view returns (uint256 balance) EIP
    function transfer(address to, uint256 value) public returns (bool);
    // function transfer(address _to, uint256 _value) returns (bool success) EIP
    event Transfer(address indexed from, address indexed to, uint256 value);
}

contract BasicToken is ERC20Basic {
    using SafeMath for uint256;

    mapping(address => uint256) balances;

    uint256 totalSupply_;

    function totalSupply() public view returns (uint256) {
        // function totalSupply() view returns (uint256 totalSupply) EIP
        return totalSupply_;
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        // function transfer(address _to, uint256 _value) returns (bool success) EIP
        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;
    }

    function balanceOf(address _owner) public view returns (uint256) {
        // function balanceOf(address _owner) view returns (uint256 balance) EIP
        return balances[_owner];
    }
}

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
    );
}

contract StandardToken is ERC20, BasicToken {

    mapping (address => mapping (address => uint256)) internal allowed;

    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;
    }

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(
        address _owner,
        address _spender
    ) public view returns (uint256)
    {
        return allowed[_owner][_spender];
    }

    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;
    }

    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;
    }
}
/************* BN Token Contract **************/
contract BNToken is StandardToken, Pausable {

    using SafeMath for uint256;

    string  public name = "BN";
    string  public symbol = "BN";
    uint256 constant public decimals = 18;
    uint256 constant dec = 10**decimals;
    uint256 public initialSupply = 50000*dec;
    uint256 public availableSupply;
    address public crowdsaleAddress;

    modifier onlyICO() {
        require(msg.sender == crowdsaleAddress);
        _;
    }

    constructor() public {
        totalSupply_ = totalSupply_.add(initialSupply);
        balances[owner] = balances[owner].add(initialSupply);
        availableSupply = totalSupply_;
        emit Transfer(address(0x0), this, initialSupply);
    }

    function setSaleAddress(address _saleaddress) public onlyOwner{
        crowdsaleAddress = _saleaddress;
    }

    function transferFromICO(address _to, uint256 _value) public onlyICO returns(bool) {
        require(_to != address(0x0));
        return super.transfer(_to, _value);
    }

    function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
        return super.transfer(_to, _value);
    }

    function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) {
        return super.transferFrom(_from, _to, _value);
    }

    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
        return super.approve(_spender, _value);
    }

    function increaseApproval(address _spender, uint _addedValue) public whenNotPaused returns (bool success) {
        return super.increaseApproval(_spender, _addedValue);
    }

    function decreaseApproval(address _spender, uint _subtractedValue) public whenNotPaused returns (bool success) {
        return super.decreaseApproval(_spender, _subtractedValue);
    }
}