Jarmo van de Seijp Solidity project ERC223 token offering Shadowbox project

1. pragma solidity ^0.4.9;
/*
https://github.com/LykkeCity/EthereumApiDotNetCore/blob/master/src/ContractBuilder/contr
acts/token/SafeMath.sol */
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 ContractReceiver {
function tokenFallback(address _from, uint _value, bytes _data);
}
contract ERC223Token is SafeMath {
event Transfer(address indexed _from, address indexed _to, uint256 _value, bytes _data);
mapping(address => uint) balances;
string public name = "Shadow Box";
string public symbol = "SHBOX";
uint8 public decimals = 18;
uint256 public totalSupply;
function ERC223Token()
{
//Supply of 100 tokens with 18 decimals. (100 + 18 times zero)
balances[0xb659871eA0bF341D3DE8AD768873bed169A8B87a] = 100000000 *
10**uint(decimals);
totalSupply = balances[0xb659871eA0bF341D3DE8AD768873bed169A8B87a];

2. }
// 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 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);
assert(_to.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);
}

3. }
// 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;
}

4. function balanceOf(address _owner) constant returns (uint balance) {
return balances[_owner];
}
}