pragma solidity ^0.4.18;


/**
 * @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);
}


/**
 * @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) {
    if (a == 0) {
      return 0;
    }
    uint256 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 c;
  }

  /**
  * @dev Substracts 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) {
    uint256 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_;

    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        // SafeMath.sub will throw if there is not enough balance.
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balances[_owner];
    }

}


/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract BurnableToken is BasicToken {

    event Burn(address indexed burner, uint256 value);


    function burn(uint256 _value) public {
        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);
        Burn(burner, _value);
        Transfer(burner, address(0), _value);
    }
}


/**
 * @title ERC20 interface
 */
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 ERC827 interface, an extension of ERC20 token standard
   Interface of a ERC827 token, following the ERC20 standard with extra
   methods to transfer value and data and execute calls in transfers and
   approvals.
 */
contract ERC827 is ERC20 {

    function approve( address _spender, uint256 _value, bytes _data ) public returns (bool);
    function transfer( address _to, uint256 _value, bytes _data ) public returns (bool);
    function transferFrom( address _from, address _to, uint256 _value, bytes _data ) public returns (bool);

}


/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 */
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);
        Transfer(_from, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        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);
        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);
        }
        Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

}


/**
   @title ERC827, an extension of ERC20 token standard
   Implementation the ERC827, following the ERC20 standard with extra
   methods to transfer value and data and execute calls in transfers and
   approvals.
 */
contract ERC827Token is ERC827, StandardToken {

    function approve(address _spender, uint256 _value, bytes _data) public returns (bool) {
        require(_spender != address(this));

        super.approve(_spender, _value);

        require(_spender.call(_data));

        return true;
    }

    function transfer(address _to, uint256 _value, bytes _data) public returns (bool) {
        require(_to != address(this));

        super.transfer(_to, _value);

        require(_to.call(_data));
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value, bytes _data) public returns (bool) {
        require(_to != address(this));

        super.transferFrom(_from, _to, _value);

        require(_to.call(_data));
        return true;
    }

    function increaseApproval(address _spender, uint _addedValue, bytes _data) public returns (bool) {
        require(_spender != address(this));

        super.increaseApproval(_spender, _addedValue);

        require(_spender.call(_data));

        return true;
    }

    function decreaseApproval(address _spender, uint _subtractedValue, bytes _data) public returns (bool) {
        require(_spender != address(this));

        super.decreaseApproval(_spender, _subtractedValue);

        require(_spender.call(_data));

        return true;
    }

}


/**
 * @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));
        OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }

}


/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
    event Pause();
    event Unpause();

    bool public paused = false;


    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     */
    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     */
    modifier whenPaused() {
        require(paused);
        _;
    }

    /**
     * @dev called by the owner to pause, triggers stopped state
     */
    function pause() onlyOwner whenNotPaused public {
        paused = true;
        Pause();
    }

    /**
     * @dev called by the owner to unpause, returns to normal state
     */
    function unpause() onlyOwner whenPaused public {
        paused = false;
        Unpause();
    }
}


/**
 * @title Pausable token
 * @dev StandardToken modified with pausable transfers.
 **/
contract PausableToken is StandardToken, Pausable {

    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);
    }
}


/**
 * @title Pausable ERC827 token
 * @dev ERC827 token modified with pausable functions.
 **/
contract PausableERC827Token is ERC827Token, PausableToken {

    function transfer(address _to, uint256 _value, bytes _data) public whenNotPaused returns (bool) {
        return super.transfer(_to, _value, _data);
    }

    function transferFrom(address _from, address _to, uint256 _value, bytes _data) public whenNotPaused returns (bool) {
        return super.transferFrom(_from, _to, _value, _data);
    }

    function approve(address _spender, uint256 _value, bytes _data) public whenNotPaused returns (bool) {
        return super.approve(_spender, _value, _data);
    }

    function increaseApproval(address _spender, uint _addedValue, bytes _data) public whenNotPaused returns (bool) {
        return super.increaseApproval(_spender, _addedValue, _data);
    }

    function decreaseApproval(address _spender, uint _subtractedValue, bytes _data) public whenNotPaused returns (bool) {
        return super.decreaseApproval(_spender, _subtractedValue, _data);
    }
}


contract PocketCoin is PausableERC827Token, BurnableToken {

    string public constant name = "Pocket Coin";
    string public constant symbol = "PKTC";
    uint32 public constant decimals = 14;

    function PocketCoin() public {
        totalSupply_ = 500000000E14;
        balances[owner] = totalSupply_; // Add all tokens to issuer balance (crowdsale in this case)
    }

}