pragma solidity ^0.4.4;

contract Token {

    uint private supply = 0;

    address public tokenManager;

    mapping (address => uint256) private balance;
    mapping (address => mapping(address => uint256)) private allowed;

    modifier onlyTokenManager()     { if(msg.sender != tokenManager) throw; _; }

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);


    function Token(address _tokenManager) {
        tokenManager = _tokenManager;
    }

    function() {
        throw;
    }

    function createTokens(uint amount) onlyTokenManager {
        supply += amount;
        balance[msg.sender] += amount;
    }

    function destroyTokens(uint amount) onlyTokenManager {
        if (amount > balance[msg.sender]) {
            throw;
        }
        supply -= amount;
        balance[msg.sender] -= amount;
    }

    function balanceOf(address _owner) constant returns (uint256 balanceOf) {
        return balance[_owner];
    }

    function totalSupply() constant returns (uint256 totalSupply) {
        return supply;
    }

    function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    function transfer(address _to, uint256 _value) returns (bool success)
    {
        if (balance[msg.sender] >= _value && _value > 0) {
            balance[msg.sender] -= _value;
            balance[_to] += _value;
            Transfer(msg.sender,_to,_value);
            return true;
        }
        return false;
    }

    function approve(address _spender, uint256 _value) returns (bool success) {
        if (balance[msg.sender] >= _value && _value > 0) {
            allowed[msg.sender][_spender] = _value;
            Approval(msg.sender,_spender,_value);
            return true;
        }
        return false;
    }


    function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {

        if (allowed[_from][msg.sender] >= _value && balance[_from] >= _value && _value >= 0)
        {
            allowed[_from][msg.sender] -= _value;
            balance[_from] -= _value;
            balance[_to] += _value;
            Transfer(_from,_to,_value);
            return true;
        }

        return false;
    }
}