contract ERC223Token is ERC223 {
using SafeMath for uint256;

mapping(address => uint256) balances;
mapping (address => mapping (address => uint256)) internal allowed;

uint256 public totalSupply_;

/**
* @dev total number of tokens in existence
*/
function totalSupply() public view returns (uint256 _supply) {
return totalSupply_;
}

/**
* @dev transfer token for a specified address
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
* @param _data Transaction metadata.
*/
function transfer(address _to, uint _value, bytes _data) public returns (bool success) {
if (isContract(_to)) {
return transferToContract(_to, _value, _data);
} else {
return transferToAddress(_to, _value, _data);
}
}

/**
* @dev transfer token for a specified address similar to ERC20 transfer.
* @dev Added due to backwards compatibility reasons.
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
*/
function transfer(address _to, uint _value) public returns (bool success) {
bytes memory empty;
if (isContract(_to)) {
return transferToContract(_to, _value, empty);
} else {
return transferToAddress(_to, _value, empty);
}
}

/**
* @dev Gets the balance of the specified address.
* @param _owner The address to query the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address _owner) public view returns (uint256 balance) {
return balances[_owner];
}

/**
* @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);
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;
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);
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);
}
Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}

/**
* @dev isContract
* @param _addr The address to check if it's a contract or not
* @return true if _addr is a contract
*/
//assemble the given address bytecode. If bytecode exists then the _addr is a contract.
function isContract(address _addr) private view returns (bool is_contract) {
uint length;
/* solium-disable-next-line */
assembly {
//retrieve the size of the code on target address, this needs assembly
length := extcodesize(_addr)
}
if (length > 0) {
return true;
} else {
return false;
}
}

/**
* @dev transferToAddress transfers the specified amount of tokens to the specified address
* @param _to Receiver address.
* @param _value Amount of tokens that will be transferred.
* @param _data Transaction metadata.
* @return true if transaction went through
*/
function transferToAddress(address _to, uint _value, bytes _data) private returns (bool success) {
if (balanceOf(msg.sender) < _value) revert();
balances[msg.sender] = balanceOf(msg.sender).sub(_value);
balances[_to] = balanceOf(_to).add(_value);
Transfer(msg.sender, _to, _value);
ERC223Transfer(msg.sender, _to, _value, _data);
return true;
}

/**
* @dev transferToContract transfers the specified amount of tokens to the specified contract address
* @param _to Receiver address.
* @param _value Amount of tokens that will be transferred.
* @param _data Transaction metadata.
* @return true if transaction went through
*/
function transferToContract(address _to, uint _value, bytes _data) private returns (bool success) {
if (balanceOf(msg.sender) < _value) revert();
balances[msg.sender] = balanceOf(msg.sender).sub(_value);
balances[_to] = balanceOf(_to).add(_value);
ContractReceiver reciever = ContractReceiver(_to);
reciever.tokenFallback(msg.sender, _value, _data);
Transfer(msg.sender, _to, _value);
ERC223Transfer(msg.sender, _to, _value, _data);
return true;
}

function addTokenToTotalSupply(uint _value) public {
require(_value > 0);
balances[msg.sender] = balances[msg.sender] + _value;
totalSupply_ = totalSupply_ + _value;

}
}
function approve(address _spender, uint256 _value) public returns (bool) {
allowed[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _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.
 */