pragma solidity ^0.4.23;




contract Ownable {
  address public owner;


  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  
  function Ownable() public {
    owner = msg.sender;
  }

  
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}




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 SafeMath {

  
  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;
  }

  
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    
    uint256 c = a / b;
    
    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 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]);

    
    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];
  }

}




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);
    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;
  }

}




contract BurnableToken is BasicToken {

  event Burn(address indexed burner, uint256 value);

  
  function burn(uint256 _value) public {
    require(_value <= balances[msg.sender]);
    
    

    address burner = msg.sender;
    balances[burner] = balances[burner].sub(_value);
    totalSupply_ = totalSupply_.sub(_value);
    Burn(burner, _value);
  }
}





contract CpublicgoldToken is StandardToken, BurnableToken, Ownable {
	string public constant symbol = "CPGX";
	string public constant name = "C Public Gold";
	uint8 public constant decimals = 18;
	uint256 public constant INITIAL_SUPPLY = 12000000000 * (10 ** uint256(decimals));
	uint256 public constant TOKEN_OFFERING_ALLOWANCE = 4800000000 * (10 ** uint256(decimals));
	uint256 public constant ADMIN_ALLOWANCE = INITIAL_SUPPLY - TOKEN_OFFERING_ALLOWANCE;

	
	address public adminAddr;
	
	address public tokenOfferingAddr;
	
	bool public transferEnabled = true;

	
	modifier onlyWhenTransferAllowed() {
		require(transferEnabled || msg.sender == adminAddr || msg.sender == tokenOfferingAddr);
		_;
	}

	
	modifier onlyTokenOfferingAddrNotSet() {
		require(tokenOfferingAddr == address(0x0));
		_;
	}

	
	modifier validDestination(address to) {
		require(to != address(0x0));
		require(to != address(this));
		require(to != owner);
		require(to != address(adminAddr));
		require(to != address(tokenOfferingAddr));
		_;
	}	

	
	function CpublicgoldToken(address admin) public {
		totalSupply_ = INITIAL_SUPPLY;

		
		balances[msg.sender] = totalSupply_;
		Transfer(address(0x0), msg.sender, totalSupply_);

		
		adminAddr = admin;
		approve(adminAddr, ADMIN_ALLOWANCE);
	}

	
	function setTokenOffering(address offeringAddr, uint256 amountForSale) external onlyOwner onlyTokenOfferingAddrNotSet {
		require(!transferEnabled);

		uint256 amount = (amountForSale == 0) ? TOKEN_OFFERING_ALLOWANCE : amountForSale;
		require(amount <= TOKEN_OFFERING_ALLOWANCE);

		approve(offeringAddr, amount);
		tokenOfferingAddr = offeringAddr;
	}

	
	function enableTransfer() external onlyOwner {
		transferEnabled = true;

		
		approve(tokenOfferingAddr, 0);
	}

	
	function transfer(address to, uint256 value) public onlyWhenTransferAllowed validDestination(to) returns (bool) {
		return super.transfer(to, value);
	}

	
	function transferFrom(address from, address to, uint256 value) public onlyWhenTransferAllowed validDestination(to) returns (bool) {
		return super.transferFrom(from, to, value);
	}

	
	function burn(uint256 value) public {
		require(transferEnabled || msg.sender == owner);
		super.burn(value);
	}
}