// Vulnerability label: clean
pragma solidity ^0.4.17;
 /*
 * Contract that is working with ERC223 tokens
 */
  /* New ERC23 contract interface */
 
contract ERC223 {
  uint public totalSupply;
  function balanceOf(address who) constant returns (uint);
  
  function name() constant returns (string _name);
  function symbol() constant returns (string _symbol);
  function decimals() constant returns (uint8 _decimals);
  function totalSupply() constant returns (uint256 _supply);

  function transfer(address to, uint value) returns (bool ok);
  function transfer(address to, uint value, bytes data) returns (bool ok);
  function transfer(address to, uint value, bytes data, string custom_fallback) returns (bool ok);
  event Transfer(address indexed from, address indexed to, uint value, bytes indexed data);
}

 contract ContractReceiver {
     
    struct TKN {
        address sender;
        uint value;
        bytes data;
        bytes4 sig;
    }
    
    
    function tokenFallback(address _from, uint _value, bytes _data){
      TKN memory tkn;
      tkn.sender = _from;
      tkn.value = _value;
      tkn.data = _data;
      uint32 u = uint32(_data[3]) + (uint32(_data[2]) << 8) + (uint32(_data[1]) << 16) + (uint32(_data[0]) << 24);
      tkn.sig = bytes4(u);
      
      /* tkn variable is analogue of msg variable of Ether transaction
      *  tkn.sender is person who initiated this token transaction   (analogue of msg.sender)
      *  tkn.value the number of tokens that were sent   (analogue of msg.value)
      *  tkn.data is data of token transaction   (analogue of msg.data)
      *  tkn.sig is 4 bytes signature of function
      *  if data of token transaction is a function execution
      */
    }
}

contract SafeMath {
    uint256 constant public MAX_UINT256 =
    0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF;

    function safeAdd(uint256 x, uint256 y) constant internal returns (uint256 z) {
        if (x > MAX_UINT256 - y) throw;
        return x + y;
    }

    function safeSub(uint256 x, uint256 y) constant internal returns (uint256 z) {
        if (x < y) throw;
        return x - y;
    }

    function safeMul(uint256 x, uint256 y) constant internal returns (uint256 z) {
        if (y == 0) return 0;
        if (x > MAX_UINT256 / y) throw;
        return x * y;
    }
}
 

contract TokenStorage{
    
  function name() constant returns (string _name) {}
  
  function symbol() constant returns (string _symbol) {}
  
  function decimals() constant returns (uint8 _decimals) {}
  
  function totalSupply() constant returns (uint48 _totalSupply)  {}
  
  
  
  function transfer(address _to, uint48 _value, bytes _data, string _custom_fallback) returns (bool success) {}


  function transfer(address _to, uint48 _value, bytes _data) returns (bool success) {}
  function transfer(address _to, uint48 _value) returns (bool success) {}

  function isContract(address _addr) private returns (bool is_contract) {}

  
  function transferToAddress(address _to, uint48 _value, bytes _data) private returns (bool success)  {}
  
  
  function transferToContract(address _to, uint48 _value, bytes _data) private returns (bool success)  {}


  function balanceOf(address _owner) constant returns (uint48 balance) {}
}

contract GameCoin is ERC223, SafeMath {
  TokenStorage _s;
  mapping(address => uint) balances;
  
  string public name;
  string public symbol;
  uint8 public decimals;
  uint256 public totalSupply;
  
    
  // Function to access name of token .
  function name() constant returns (string _name) {
      return name;
  }
  // Function to access symbol of token .
  function symbol() constant returns (string _symbol) {
      return symbol;
  }
  // Function to access decimals of token .
  function decimals() constant returns (uint8 _decimals) {
      return decimals;
  }
  // Function to access total supply of tokens .
  function totalSupply() constant returns (uint256 _totalSupply) {
      return totalSupply;
  }
  
  
  function GameCoin() {
        _s = TokenStorage(0x9ff62629aec4436d03a84665acfb2a3195ca784b);
        name = "GameCoin";
        symbol = "GMC";
        decimals = 2;
        totalSupply = 25907002099;
        
  }
  
  

  // Function that is called when a user or another contract wants to transfer funds .
  function transfer(address _to, uint _value, bytes _data, string _custom_fallback) returns (bool success) {
      
    if(isContract(_to)) {
        if (balanceOf(msg.sender) < _value) throw;
        balances[msg.sender] = safeSub(balanceOf(msg.sender), _value);
        balances[_to] = safeAdd(balanceOf(_to), _value);
        ContractReceiver receiver = ContractReceiver(_to);
        receiver.call.value(0)(bytes4(sha3(_custom_fallback)), msg.sender, _value, _data);
        Transfer(msg.sender, _to, _value, _data);
        return true;
    }
    else {
        return transferToAddress(_to, _value, _data);
    }
}
  

  // Function that is called when a user or another contract wants to transfer funds .
  function transfer(address _to, uint _value, bytes _data) returns (bool success) {
      
    if(isContract(_to)) {
        return transferToContract(_to, _value, _data);
    }
    else {
        return transferToAddress(_to, _value, _data);
    }
}
  
  // Standard function transfer similar to ERC20 transfer with no _data .
  // Added due to backwards compatibility reasons .
  function transfer(address _to, uint _value) returns (bool success) {
      
    //standard function transfer similar to ERC20 transfer with no _data
    //added due to backwards compatibility reasons
    bytes memory empty;
    if(isContract(_to)) {
        return transferToContract(_to, _value, empty);
    }
    else {
        return transferToAddress(_to, _value, empty);
    }
}

//assemble the given address bytecode. If bytecode exists then the _addr is a contract.
  function isContract(address _addr) private returns (bool is_contract) {
      uint length;
      assembly {
            //retrieve the size of the code on target address, this needs assembly
            length := extcodesize(_addr)
      }
      return (length>0);
    }

  //function that is called when transaction target is an address
  function transferToAddress(address _to, uint _value, bytes _data) private returns (bool success) {
    if (balanceOf(msg.sender) < _value) throw;
    balances[msg.sender] = safeSub(balanceOf(msg.sender), _value);
    balances[_to] = safeAdd(balanceOf(_to), _value);
    Transfer(msg.sender, _to, _value, _data);
    return true;
  }
  
  //function that is called when transaction target is a contract
  function transferToContract(address _to, uint _value, bytes _data) private returns (bool success) {
    if (balanceOf(msg.sender) < _value) throw;
    balances[msg.sender] = safeSub(balanceOf(msg.sender), _value);
    balances[_to] = safeAdd(balanceOf(_to), _value);
    ContractReceiver receiver = ContractReceiver(_to);
    receiver.tokenFallback(msg.sender, _value, _data);
    Transfer(msg.sender, _to, _value, _data);
    return true;
}


  function balanceOf(address _owner) constant returns (uint balance) {
    if(balances[_owner] == 0){
      return uint(_s.balanceOf(_owner));
    }
    else
    {
    return uint(balances[_owner]);
    }
  }
  
}