pragma solidity ^0.4.24;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that revert on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, reverts on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (a == 0) {
      return 0;
    }

    uint256 c = a * b;
    require(c / a == b);

    return c;
  }

  /**
  * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0); // Solidity only automatically asserts when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold

    return c;
  }

  /**
  * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a);
    uint256 c = a - b;

    return c;
  }

  /**
  * @dev Adds two numbers, reverts on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a);

    return c;
  }

  /**
  * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
  * reverts when dividing by zero.
  */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}


/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
  function totalSupply() external view returns (uint256);

  function balanceOf(address who) external view returns (uint256);

  function allowance(address owner, address spender)
    external view returns (uint256);

  function transfer(address to, uint256 value) external returns (bool);

  function approve(address spender, uint256 value)
    external returns (bool);

  function transferFrom(address from, address to, uint256 value)
    external returns (bool);

  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value
  );

  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}


/**
 * Abstract contract, requires implementation to specify who can commit blocks and what
 *   happens when a successful proof is presented
 * Verifies Merkle-tree inclusion proofs that show that certain address has
 *   certain earnings balance, according to hash published ("signed") by a
 *   sidechain operator or similar authority
 *
 * ABOUT Merkle-tree inclusion proof: Merkle-tree inclusion proof is an algorithm to prove memebership
 * in a set using minimal [ie log(N)] inputs. The hashes of the items are arranged by hash value in a binary Merkle tree where 
 * each node contains a hash of the hashes of nodes below. The root node (ie "root hash") contains hash information 
 * about the entire set, and that is the data that BalanceVerifier posts to the blockchain. To prove membership, you walk up the 
 * tree from the node in question, and use the supplied hashes (the "proof") to fill in the hashes from the adjacent nodes. The proof  
 * succeeds iff you end up with the known root hash when you get to the top of the tree. 
 * See https://medium.com/crypto-0-nite/merkle-proofs-explained-6dd429623dc5
 *
 * Merkle-tree inclusion proof is a RELATED concept to the blockchain Merkle tree, but a somewhat DIFFERENT application. 
 * BalanceVerifier posts the root hash of the CURRENT ledger only, and this does NOT depend on the hash of previous ledgers.
 * This is different from the blockchain, where each block contains the hash of the previous block. 
 *
 * TODO: see if it could be turned into a library, so many contracts could use it
 */
contract BalanceVerifier {
    event BlockCreated(uint blockNumber, bytes32 rootHash, string ipfsHash);

    /**
     * Sidechain "blocks" are simply root hashes of merkle-trees constructed from its balances
     * @param uint root-chain block number after which the balances were recorded
     * @return bytes32 root of the balances merkle-tree at that time
     */
    mapping (uint => bytes32) public blockHash;

    /**
     * Handler for proof of sidechain balances
     * It is up to the implementing contract to actually distribute out the balances
     * @param blockNumber the block whose hash was used for verification
     * @param account whose balances were successfully verified
     * @param balance the side-chain account balance
     */
    function onVerifySuccess(uint blockNumber, address account, uint balance) internal;

    /**
     * Implementing contract should should do access checks for committing
     */
    function onCommit(uint blockNumber, bytes32 rootHash, string ipfsHash) internal;

    /**
     * Side-chain operator submits commitments to main chain. These
     * For convenience, also publish the ipfsHash of the balance book JSON object
     * @param blockNumber the block after which the balances were recorded
     * @param rootHash root of the balances merkle-tree
     * @param ipfsHash where the whole balances object can be retrieved in JSON format
     */
    function commit(uint blockNumber, bytes32 rootHash, string ipfsHash) external {
        require(blockHash[blockNumber] == 0, "error_overwrite");
        string memory _hash = ipfsHash;
        onCommit(blockNumber, rootHash, _hash);
        blockHash[blockNumber] = rootHash;
        emit BlockCreated(blockNumber, rootHash, _hash);
    }

    /**
     * Proving can be used to record the sidechain balances permanently into root chain
     * @param blockNumber the block after which the balances were recorded
     * @param account whose balances will be verified
     * @param balance side-chain account balance
     * @param proof list of hashes to prove the totalEarnings
     */
    function prove(uint blockNumber, address account, uint balance, bytes32[] memory proof) public {
        require(proofIsCorrect(blockNumber, account, balance, proof), "error_proof");
        onVerifySuccess(blockNumber, account, balance);
    }

    /**
     * Check the merkle proof of balance in the given side-chain block for given account
     */
    function proofIsCorrect(uint blockNumber, address account, uint balance, bytes32[] memory proof) public view returns(bool) {
        bytes32 hash = keccak256(abi.encodePacked(account, balance));
        bytes32 rootHash = blockHash[blockNumber];
        require(rootHash != 0x0, "error_blockNotFound");
        return rootHash == calculateRootHash(hash, proof);
    }

    /**
     * Calculate root hash of a Merkle tree, given
     * @param hash of the leaf to verify
     * @param others list of hashes of "other" branches
     */
    function calculateRootHash(bytes32 hash, bytes32[] memory others) public pure returns (bytes32 root) {
        root = hash;
        for (uint8 i = 0; i < others.length; i++) {
            bytes32 other = others[i];
            if (other == 0x0) continue;     // odd branch, no need to hash
            if (root < other) {
                root = keccak256(abi.encodePacked(root, other));
            } else {
                root = keccak256(abi.encodePacked(other, root));
            }
        }
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;
    address public pendingOwner;

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

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(msg.sender == owner, "onlyOwner");
        _;
    }

    /**
     * @dev Allows the current owner to set the pendingOwner address.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        pendingOwner = newOwner;
    }

    /**
     * @dev Allows the pendingOwner address to finalize the transfer.
     */
    function claimOwnership() public {
        require(msg.sender == pendingOwner, "onlyPendingOwner");
        emit OwnershipTransferred(owner, pendingOwner);
        owner = pendingOwner;
        pendingOwner = address(0);
    }
}




/**
 * Monoplasma that is managed by an owner, likely the side-chain operator
 * Owner can add and remove recipients.
 */
contract Monoplasma is BalanceVerifier, Ownable {
    using SafeMath for uint256;

    event OperatorChanged(address indexed newOperator);
    event AdminFeeChanged(uint adminFee);
    /**
     * Freeze period during which all side-chain participants should be able to
     *   acquire the whole balance book from IPFS (or HTTP server, or elsewhere)
     *   and validate that the published rootHash is correct
     * In case of incorrect rootHash, all members should issue withdrawals from the
     *   latest block they have validated (that is older than blockFreezeSeconds)
     * So: too short freeze period + bad availability => ether (needlessly) spent withdrawing earnings
     *     long freeze period == lag between purchase and withdrawal => bad UX
     * Blocks older than blockFreezeSeconds can be used to withdraw funds
     */
    uint public blockFreezeSeconds;

    /**
     * Block number => timestamp
     * Publish time of a block, where the block freeze period starts from.
     * Note that block number points to the block after which the root hash is calculated,
     *   not the block where BlockCreated was emitted (event must come later)
     */
    mapping (uint => uint) public blockTimestamp;

    address public operator;

    //fee fraction = adminFee/10^18
    uint public adminFee;

    IERC20 public token;

    mapping (address => uint) public earnings;
    mapping (address => uint) public withdrawn;
    uint public totalWithdrawn;
    uint public totalProven;

    constructor(address tokenAddress, uint blockFreezePeriodSeconds, uint _adminFee) public {
        blockFreezeSeconds = blockFreezePeriodSeconds;
        token = IERC20(tokenAddress);
        operator = msg.sender;
        setAdminFee(_adminFee);
    }

    function setOperator(address newOperator) public onlyOwner {
        operator = newOperator;
        emit OperatorChanged(newOperator);
    }

    /**
     * Admin fee as a fraction of revenue
     * Fixed-point decimal in the same way as ether: 50% === 0.5 ether
     * Smart contract doesn't use it, it's here just for storing purposes
     */
    function setAdminFee(uint _adminFee) public onlyOwner {
        require(adminFee <= 1 ether, "Admin fee cannot be greater than 1");
        adminFee = _adminFee;
        emit AdminFeeChanged(_adminFee);
    }

    /**
     * Operator creates the side-chain blocks
     */
    function onCommit(uint blockNumber, bytes32, string) internal {
        require(msg.sender == operator, "error_notPermitted");
        blockTimestamp[blockNumber] = now;
    }

    /**
     * Called from BalanceVerifier.prove
     * Prove can be called directly to withdraw less than the whole share,
     *   or just "cement" the earnings so far into root chain even without withdrawing
     */
    function onVerifySuccess(uint blockNumber, address account, uint newEarnings) internal {
        uint blockFreezeStart = blockTimestamp[blockNumber];
        require(now > blockFreezeStart + blockFreezeSeconds, "error_frozen");
        require(earnings[account] < newEarnings, "error_oldEarnings");
        totalProven = totalProven.add(newEarnings).sub(earnings[account]);
        require(totalProven.sub(totalWithdrawn) <= token.balanceOf(this), "error_missingBalance");
        earnings[account] = newEarnings;
    }

    /**
     * Prove and withdraw the whole revenue share from sidechain in one transaction
     * @param blockNumber of the leaf to verify
     * @param totalEarnings in the side-chain
     * @param proof list of hashes to prove the totalEarnings
     */
    function withdrawAll(uint blockNumber, uint totalEarnings, bytes32[] proof) external {
        withdrawAllFor(msg.sender, blockNumber, totalEarnings, proof);
    }

    /**
     * Prove and withdraw the whole revenue share for someone else
     * Validator needs to exit those it's watching out for, in case
     *   it detects Operator malfunctioning
     * @param recipient the address we're proving and withdrawing
     * @param blockNumber of the leaf to verify
     * @param totalEarnings in the side-chain
     * @param proof list of hashes to prove the totalEarnings
     */
    function withdrawAllFor(address recipient, uint blockNumber, uint totalEarnings, bytes32[] proof) public {
        prove(blockNumber, recipient, totalEarnings, proof);
        uint withdrawable = totalEarnings.sub(withdrawn[recipient]);
        withdrawTo(recipient, recipient, withdrawable);
    }

    /**
     * "Donate withdraw" function that allows you to prove and transfer
     *   your earnings to a another address in one transaction
     * @param recipient the address the tokens will be sent to (instead of msg.sender)
     * @param blockNumber of the leaf to verify
     * @param totalEarnings in the side-chain
     * @param proof list of hashes to prove the totalEarnings
     */
    function withdrawAllTo(address recipient, uint blockNumber, uint totalEarnings, bytes32[] proof) external {
        prove(blockNumber, msg.sender, totalEarnings, proof);
        uint withdrawable = totalEarnings.sub(withdrawn[msg.sender]);
        withdrawTo(recipient, msg.sender, withdrawable);
    }

    /**
     * Withdraw a specified amount of your own proven earnings (see `function prove`)
     */
    function withdraw(uint amount) public {
        withdrawTo(msg.sender, msg.sender, amount);
    }

    /**
     * Do the withdrawal on behalf of someone else
     * Validator needs to exit those it's watching out for, in case
     *   it detects Operator malfunctioning
     */
    function withdrawFor(address recipient, uint amount) public {
        withdrawTo(recipient, recipient, amount);
    }

    /**
     * Execute token withdrawal into specified recipient address from specified member account
     * @dev It is up to the sidechain implementation to make sure
     * @dev  always token balance >= sum of earnings - sum of withdrawn
     */
    function withdrawTo(address recipient, address account, uint amount) public {
        require(amount > 0, "error_zeroWithdraw");
        uint w = withdrawn[account].add(amount);
        require(w <= earnings[account], "error_overdraft");
        withdrawn[account] = w;
        totalWithdrawn = totalWithdrawn.add(amount);
        require(token.transfer(recipient, amount), "error_transfer");
    }
}


contract CommunityProduct is Monoplasma {

    string public joinPartStream;

    constructor(address operator, string joinPartStreamId, address tokenAddress, uint blockFreezePeriodSeconds, uint adminFeeFraction)
    Monoplasma(tokenAddress, blockFreezePeriodSeconds, adminFeeFraction) public {
        setOperator(operator);
        joinPartStream = joinPartStreamId;
    }
}

/*
 * ERC20 interface
 * see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 {
  uint public totalSupply;
  function balanceOf(address who) constant returns (uint);
  function allowance(address owner, address spender) constant returns (uint);

  function transfer(address to, uint value) returns (bool ok);
  function transferFrom(address from, address to, uint value) returns (bool ok);
  function approve(address spender, uint value) returns (bool ok);
  event Transfer(address indexed from, address indexed to, uint value);
  event Approval(address indexed owner, address indexed spender, uint value);
}



/**
 * Math operations with safety checks
 */
contract SafeMath {
  function safeMul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint a, uint b) internal returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function safeSub(uint a, uint b) internal returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) internal returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }

  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }

  function assert(bool assertion) internal {
    if (!assertion) {
      throw;
    }
  }
}



/**
 * Standard ERC20 token with Short Hand Attack and approve() race condition mitigation.
 *
 * Based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, SafeMath {

  /* Token supply got increased and a new owner received these tokens */
  event Minted(address receiver, uint amount);

  /* Actual balances of token holders */
  mapping(address => uint) balances;

  /* approve() allowances */
  mapping (address => mapping (address => uint)) allowed;

  /* Interface declaration */
  function isToken() public constant returns (bool weAre) {
    return true;
  }

  function transfer(address _to, uint _value) returns (bool success) {
    balances[msg.sender] = safeSub(balances[msg.sender], _value);
    balances[_to] = safeAdd(balances[_to], _value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  function transferFrom(address _from, address _to, uint _value) returns (bool success) {
    uint _allowance = allowed[_from][msg.sender];

    balances[_to] = safeAdd(balances[_to], _value);
    balances[_from] = safeSub(balances[_from], _value);
    allowed[_from][msg.sender] = safeSub(_allowance, _value);
    Transfer(_from, _to, _value);
    return true;
  }

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

  function approve(address _spender, uint _value) returns (bool success) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    if ((_value != 0) && (allowed[msg.sender][_spender] != 0)) throw;

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

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

}





/**
 * Upgrade agent interface inspired by Lunyr.
 *
 * Upgrade agent transfers tokens to a new contract.
 * Upgrade agent itself can be the token contract, or just a middle man contract doing the heavy lifting.
 */
contract UpgradeAgent {

  uint public originalSupply;

  /** Interface marker */
  function isUpgradeAgent() public constant returns (bool) {
    return true;
  }

  function upgradeFrom(address _from, uint256 _value) public;

}


/**
 * A token upgrade mechanism where users can opt-in amount of tokens to the next smart contract revision.
 *
 * First envisioned by Golem and Lunyr projects.
 */
contract UpgradeableToken is StandardToken {

  /** Contract / person who can set the upgrade path. This can be the same as team multisig wallet, as what it is with its default value. */
  address public upgradeMaster;

  /** The next contract where the tokens will be migrated. */
  UpgradeAgent public upgradeAgent;

  /** How many tokens we have upgraded by now. */
  uint256 public totalUpgraded;

  /**
   * Upgrade states.
   *
   * - NotAllowed: The child contract has not reached a condition where the upgrade can bgun
   * - WaitingForAgent: Token allows upgrade, but we don't have a new agent yet
   * - ReadyToUpgrade: The agent is set, but not a single token has been upgraded yet
   * - Upgrading: Upgrade agent is set and the balance holders can upgrade their tokens
   *
   */
  enum UpgradeState {Unknown, NotAllowed, WaitingForAgent, ReadyToUpgrade, Upgrading}

  /**
   * Somebody has upgraded some of his tokens.
   */
  event Upgrade(address indexed _from, address indexed _to, uint256 _value);

  /**
   * New upgrade agent available.
   */
  event UpgradeAgentSet(address agent);

  /**
   * Do not allow construction without upgrade master set.
   */
  function UpgradeableToken(address _upgradeMaster) {
    upgradeMaster = _upgradeMaster;
  }

  /**
   * Allow the token holder to upgrade some of their tokens to a new contract.
   */
  function upgrade(uint256 value) public {

      UpgradeState state = getUpgradeState();
      if(!(state == UpgradeState.ReadyToUpgrade || state == UpgradeState.Upgrading)) {
        // Called in a bad state
        throw;
      }

      // Validate input value.
      if (value == 0) throw;

      balances[msg.sender] = safeSub(balances[msg.sender], value);

      // Take tokens out from circulation
      totalSupply = safeSub(totalSupply, value);
      totalUpgraded = safeAdd(totalUpgraded, value);

      // Upgrade agent reissues the tokens
      upgradeAgent.upgradeFrom(msg.sender, value);
      Upgrade(msg.sender, upgradeAgent, value);
  }

  /**
   * Set an upgrade agent that handles
   */
  function setUpgradeAgent(address agent) external {

      if(!canUpgrade()) {
        // The token is not yet in a state that we could think upgrading
        throw;
      }

      if (agent == 0x0) throw;
      // Only a master can designate the next agent
      if (msg.sender != upgradeMaster) throw;
      // Upgrade has already begun for an agent
      if (getUpgradeState() == UpgradeState.Upgrading) throw;

      upgradeAgent = UpgradeAgent(agent);

      // Bad interface
      if(!upgradeAgent.isUpgradeAgent()) throw;
      // Make sure that token supplies match in source and target
      if (upgradeAgent.originalSupply() != totalSupply) throw;

      UpgradeAgentSet(upgradeAgent);
  }

  /**
   * Get the state of the token upgrade.
   */
  function getUpgradeState() public constant returns(UpgradeState) {
    if(!canUpgrade()) return UpgradeState.NotAllowed;
    else if(address(upgradeAgent) == 0x00) return UpgradeState.WaitingForAgent;
    else if(totalUpgraded == 0) return UpgradeState.ReadyToUpgrade;
    else return UpgradeState.Upgrading;
  }

  /**
   * Change the upgrade master.
   *
   * This allows us to set a new owner for the upgrade mechanism.
   */
  function setUpgradeMaster(address master) public {
      if (master == 0x0) throw;
      if (msg.sender != upgradeMaster) throw;
      upgradeMaster = master;
  }

  /**
   * Child contract can enable to provide the condition when the upgrade can begun.
   */
  function canUpgrade() public constant returns(bool) {
     return true;
  }

}




/*
 * Ownable
 *
 * Base contract with an owner.
 * Provides onlyOwner modifier, which prevents function from running if it is called by anyone other than the owner.
 */
contract Ownable {
  address public owner;

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

  modifier onlyOwner() {
    if (msg.sender != owner) {
      throw;
    }
    _;
  }

  function transferOwnership(address newOwner) onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}




/**
 * Define interface for releasing the token transfer after a successful crowdsale.
 */
contract ReleasableToken is ERC20, Ownable {

  /* The finalizer contract that allows unlift the transfer limits on this token */
  address public releaseAgent;

  /** A crowdsale contract can release us to the wild if ICO success. If false we are are in transfer lock up period.*/
  bool public released = false;

  /** Map of agents that are allowed to transfer tokens regardless of the lock down period. These are crowdsale contracts and possible the team multisig itself. */
  mapping (address => bool) public transferAgents;

  /**
   * Limit token transfer until the crowdsale is over.
   *
   */
  modifier canTransfer(address _sender) {

    if(!released) {
        if(!transferAgents[_sender]) {
            throw;
        }
    }

    _;
  }

  /**
   * Set the contract that can call release and make the token transferable.
   *
   * Design choice. Allow reset the release agent to fix fat finger mistakes.
   */
  function setReleaseAgent(address addr) onlyOwner inReleaseState(false) public {

    // We don't do interface check here as we might want to a normal wallet address to act as a release agent
    releaseAgent = addr;
  }

  /**
   * Owner can allow a particular address (a crowdsale contract) to transfer tokens despite the lock up period.
   */
  function setTransferAgent(address addr, bool state) onlyOwner inReleaseState(false) public {
    transferAgents[addr] = state;
  }

  /**
   * One way function to release the tokens to the wild.
   *
   * Can be called only from the release agent that is the final ICO contract. It is only called if the crowdsale has been success (first milestone reached).
   */
  function releaseTokenTransfer() public onlyReleaseAgent {
    released = true;
  }

  /** The function can be called only before or after the tokens have been releasesd */
  modifier inReleaseState(bool releaseState) {
    if(releaseState != released) {
        throw;
    }
    _;
  }

  /** The function can be called only by a whitelisted release agent. */
  modifier onlyReleaseAgent() {
    if(msg.sender != releaseAgent) {
        throw;
    }
    _;
  }

  function transfer(address _to, uint _value) canTransfer(msg.sender) returns (bool success) {
    // Call StandardToken.transfer()
   return super.transfer(_to, _value);
  }

  function transferFrom(address _from, address _to, uint _value) canTransfer(_from) returns (bool success) {
    // Call StandardToken.transferForm()
    return super.transferFrom(_from, _to, _value);
  }

}





/**
 * Safe unsigned safe math.
 *
 * https://blog.aragon.one/library-driven-development-in-solidity-2bebcaf88736#.750gwtwli
 *
 * Originally from https://raw.githubusercontent.com/AragonOne/zeppelin-solidity/master/contracts/SafeMathLib.sol
 *
 * Maintained here until merged to mainline zeppelin-solidity.
 *
 */
library SafeMathLib {

  function times(uint a, uint b) returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function minus(uint a, uint b) returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function plus(uint a, uint b) returns (uint) {
    uint c = a + b;
    assert(c>=a);
    return c;
  }

  function assert(bool assertion) private {
    if (!assertion) throw;
  }
}



/**
 * A token that can increase its supply by another contract.
 *
 * This allows uncapped crowdsale by dynamically increasing the supply when money pours in.
 * Only mint agents, contracts whitelisted by owner, can mint new tokens.
 *
 */
contract MintableToken is StandardToken, Ownable {

  using SafeMathLib for uint;

  bool public mintingFinished = false;

  /** List of agents that are allowed to create new tokens */
  mapping (address => bool) public mintAgents;

  event MintingAgentChanged(address addr, bool state  );

  /**
   * Create new tokens and allocate them to an address..
   *
   * Only callably by a crowdsale contract (mint agent).
   */
  function mint(address receiver, uint amount) onlyMintAgent canMint public {
    totalSupply = totalSupply.plus(amount);
    balances[receiver] = balances[receiver].plus(amount);

    // This will make the mint transaction apper in EtherScan.io
    // We can remove this after there is a standardized minting event
    Transfer(0, receiver, amount);
  }

  /**
   * Owner can allow a crowdsale contract to mint new tokens.
   */
  function setMintAgent(address addr, bool state) onlyOwner canMint public {
    mintAgents[addr] = state;
    MintingAgentChanged(addr, state);
  }

  modifier onlyMintAgent() {
    // Only crowdsale contracts are allowed to mint new tokens
    if(!mintAgents[msg.sender]) {
        throw;
    }
    _;
  }

  /** Make sure we are not done yet. */
  modifier canMint() {
    if(mintingFinished) throw;
    _;
  }
}



/**
 * A crowdsaled token.
 *
 * An ERC-20 token designed specifically for crowdsales with investor protection and further development path.
 *
 * - The token transfer() is disabled until the crowdsale is over
 * - The token contract gives an opt-in upgrade path to a new contract
 * - The same token can be part of several crowdsales through approve() mechanism
 * - The token can be capped (supply set in the constructor) or uncapped (crowdsale contract can mint new tokens)
 *
 */
contract CrowdsaleToken is ReleasableToken, MintableToken, UpgradeableToken {

  /** Name and symbol were updated. */
  event UpdatedTokenInformation(string newName, string newSymbol);

  string public name;

  string public symbol;

  uint public decimals;

  /**
   * Construct the token.
   *
   * This token must be created through a team multisig wallet, so that it is owned by that wallet.
   *
   * @param _name Token name
   * @param _symbol Token symbol - should be all caps
   * @param _initialSupply How many tokens we start with
   * @param _decimals Number of decimal places
   * @param _mintable Are new tokens created over the crowdsale or do we distribute only the initial supply? Note that when the token becomes transferable the minting always ends.
   */
  function CrowdsaleToken(string _name, string _symbol, uint _initialSupply, uint _decimals, bool _mintable)
    UpgradeableToken(msg.sender) {

    // Create any address, can be transferred
    // to team multisig via changeOwner(),
    // also remember to call setUpgradeMaster()
    owner = msg.sender;

    name = _name;
    symbol = _symbol;

    totalSupply = _initialSupply;

    decimals = _decimals;

    // Create initially all balance on the team multisig
    balances[owner] = totalSupply;

    if(totalSupply > 0) {
      Minted(owner, totalSupply);
    }

    // No more new supply allowed after the token creation
    if(!_mintable) {
      mintingFinished = true;
      if(totalSupply == 0) {
        throw; // Cannot create a token without supply and no minting
      }
    }
  }

  /**
   * When token is released to be transferable, enforce no new tokens can be created.
   */
  function releaseTokenTransfer() public onlyReleaseAgent {
    mintingFinished = true;
    super.releaseTokenTransfer();
  }

  /**
   * Allow upgrade agent functionality kick in only if the crowdsale was success.
   */
  function canUpgrade() public constant returns(bool) {
    return released && super.canUpgrade();
  }

  /**
   * Owner can update token information here.
   *
   * It is often useful to conceal the actual token association, until
   * the token operations, like central issuance or reissuance have been completed.
   *
   * This function allows the token owner to rename the token after the operations
   * have been completed and then point the audience to use the token contract.
   */
  function setTokenInformation(string _name, string _symbol) onlyOwner {
    name = _name;
    symbol = _symbol;

    UpdatedTokenInformation(name, symbol);
  }

}