contract Tollar is Ownable, ERC20Detailed {
    // PLEASE READ BEFORE CHANGING ANY ACCOUNTING OR MATH
    // Anytime there is division, there is a risk of numerical instability from rounding errors. In
    // order to minimize this risk, we adhere to the following guidelines:
    // 1) The conversion rate adopted is the number of gons that equals 1 fragment.
    //    The inverse rate must not be used--TOTAL_GONS is always the numerator and _totalSupply is
    //    always the denominator. (i.e. If you want to convert gons to fragments instead of
    //    multiplying by the inverse rate, you should divide by the normal rate)
    // 2) Gon balances converted into Fragments are always rounded down (truncated).
    //
    // We make the following guarantees:
    // - If address 'A' transfers x Fragments to address 'B'. A's resulting external balance will
    //   be decreased by precisely x Fragments, and B's external balance will be precisely
    //   increased by x Fragments.
    //
    // We do not guarantee that the sum of all balances equals the result of calling totalSupply().
    // This is because, for any conversion function 'f()' that has non-zero rounding error,
    // f(x0) + f(x1) + ... + f(xn) is not always equal to f(x0 + x1 + ... xn).

    using SafeMath for uint256;
    using SafeMathInt for int256;

    struct Transaction {
        bool enabled;
        address destination;
        bytes data;
    }

    event TransactionFailed(address indexed destination, uint index, bytes data);

    // Stable ordering is not guaranteed.

    Transaction[] public transactions;

    event LogRebase(uint256 indexed epoch, uint256 totalSupply);

    uint256 private constant DECIMALS = 9;
    uint256 private constant MAX_UINT256 = ~uint256(0);
    uint256 private constant INITIAL_FRAGMENTS_SUPPLY = 1000000 * 10**DECIMALS;

    // TOTAL_GONS is a multiple of INITIAL_FRAGMENTS_SUPPLY so that _gonsPerFragment is an integer.
    // Use the highest value that fits in a uint256 for max granularity.
    uint256 private constant TOTAL_GONS = MAX_UINT256 - (MAX_UINT256 % INITIAL_FRAGMENTS_SUPPLY);

    // MAX_SUPPLY = maximum integer < (sqrt(4*TOTAL_GONS + 1) - 1) / 2
    uint256 private constant MAX_SUPPLY = ~uint128(0);  // (2^128) - 1

    uint256 private _epoch;

    uint256 private _totalSupply;
    uint256 private _gonsPerFragment;
    mapping(address => uint256) private _gonBalances;

    // This is denominated in Fragments, because the gons-fragments conversion might change before
    // it's fully paid.
    mapping (address => mapping (address => uint256)) private _allowedFragments;

    /**
     * @dev Notifies Fragments contract about a new rebase cycle.
     * @param supplyDelta The number of new fragment tokens to add into circulation via expansion.
     * @return The total number of fragments after the supply adjustment.
     */
    function rebase(int256 supplyDelta) external onlyOwner returns (uint256) {
        _epoch = _epoch.add(1);

        if (supplyDelta == 0) {
            emit LogRebase(_epoch, _totalSupply);
            return _totalSupply;
        }

        if (supplyDelta < 0) {
            _totalSupply = _totalSupply.sub(uint256(supplyDelta.abs()));
        } else {
            _totalSupply = _totalSupply.add(uint256(supplyDelta));
        }

        if (_totalSupply > MAX_SUPPLY) {
            _totalSupply = MAX_SUPPLY;
        }

        _gonsPerFragment = TOTAL_GONS.div(_totalSupply);

        // From this point forward, _gonsPerFragment is taken as the source of truth.
        // We recalculate a new _totalSupply to be in agreement with the _gonsPerFragment
        // conversion rate.
        // This means our applied supplyDelta can deviate from the requested supplyDelta,
        // but this deviation is guaranteed to be < (_totalSupply^2)/(TOTAL_GONS - _totalSupply).
        //
        // In the case of _totalSupply <= MAX_UINT128 (our current supply cap), this
        // deviation is guaranteed to be < 1, so we can omit this step. If the supply cap is
        // ever increased, it must be re-included.
        // _totalSupply = TOTAL_GONS.div(_gonsPerFragment)

        emit LogRebase(_epoch, _totalSupply);

        for (uint i = 0; i < transactions.length; i++) {
            Transaction storage t = transactions[i];
            if (t.enabled) {
                bool result = externalCall(t.destination, t.data);
                if (!result) {
                    emit TransactionFailed(t.destination, i, t.data);
                    revert("Transaction Failed");
                }
            }
        }

        return _totalSupply;
    }

    constructor() public Ownable() {
        ERC20Detailed.initialize('Tollar', 'TLR', uint8(DECIMALS));
        _totalSupply = INITIAL_FRAGMENTS_SUPPLY;
        _gonBalances[msg.sender] = TOTAL_GONS;
        _gonsPerFragment = TOTAL_GONS.div(_totalSupply);

        emit Transfer(address(0x0), msg.sender, _totalSupply);
    }

    /**
     * @return The total number of fragments.
     */
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @param who The address to query.
     * @return The balance of the specified address.
     */
    function balanceOf(address who) public view override returns (uint256) {
        return _gonBalances[who].div(_gonsPerFragment);
    }

    /**
     * @dev Transfer tokens to a specified address.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     * @return True on success, false otherwise.
     */
    function transfer(address to, uint256 value) public override returns (bool) {
        uint256 merValue = value.mul(_gonsPerFragment);
        _gonBalances[msg.sender] = _gonBalances[msg.sender].sub(merValue);
        _gonBalances[to] = _gonBalances[to].add(merValue);
        emit Transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Function to check the amount of tokens that an owner has allowed to a spender.
     * @param owner_ The address which owns the funds.
     * @param spender The address which will spend the funds.
     * @return The number of tokens still available for the spender.
     */
    function allowance(address owner_, address spender) public view override returns (uint256) {
        return _allowedFragments[owner_][spender];
    }

    /**
     * @dev Transfer tokens from one address to another.
     * @param from The address you want to send tokens from.
     * @param to The address you want to transfer to.
     * @param value The amount of tokens to be transferred.
     */
    function transferFrom(address from, address to, uint256 value) public override returns (bool) {
        _allowedFragments[from][msg.sender] = _allowedFragments[from][msg.sender].sub(value);

        uint256 merValue = value.mul(_gonsPerFragment);
        _gonBalances[from] = _gonBalances[from].sub(merValue);
        _gonBalances[to] = _gonBalances[to].add(merValue);
        emit Transfer(from, to, value);

        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of
     * msg.sender. This method is included for ERC20 compatibility.
     * increaseAllowance and decreaseAllowance should be used instead.
     * Changing an allowance with this method brings the risk that someone may transfer both
     * the old and the new allowance - if they are both greater than zero - if a transfer
     * transaction is mined before the later approve() call is mined.
     *
     * @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 override returns (bool) {
        _allowedFragments[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev Increase the amount of tokens that an owner has allowed to a spender.
     * This method should be used instead of approve() to avoid the double approval vulnerability
     * described above.
     * @param spender The address which will spend the funds.
     * @param addedValue The amount of tokens to increase the allowance by.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _allowedFragments[msg.sender][spender] =
            _allowedFragments[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowedFragments[msg.sender][spender]);
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner has allowed to a spender.
     *
     * @param spender The address which will spend the funds.
     * @param subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        uint256 oldValue = _allowedFragments[msg.sender][spender];
        if (subtractedValue >= oldValue) {
            _allowedFragments[msg.sender][spender] = 0;
        } else {
            _allowedFragments[msg.sender][spender] = oldValue.sub(subtractedValue);
        }
        emit Approval(msg.sender, spender, _allowedFragments[msg.sender][spender]);
        return true;
    }

    /**
     * @notice Adds a transaction that gets called for a downstream receiver of rebases
     * @param destination Address of contract destination
     * @param data Transaction data payload
     */
    function addTransaction(address destination, bytes memory data) external onlyOwner {
        transactions.push(Transaction({
            enabled: true,
            destination: destination,
            data: data
        }));
    }

    /**
     * @param index Index of transaction to remove.
     *              Transaction ordering may have changed since adding.
     */
    function removeTransaction(uint index) external onlyOwner {
        require(index < transactions.length, "index out of bounds");

        if (index < transactions.length - 1) {
            transactions[index] = transactions[transactions.length - 1];
        }

        transactions.pop();
    }

    /**
     * @param index Index of transaction. Transaction ordering may have changed since adding.
     * @param enabled True for enabled, false for disabled.
     */
    function setTransactionEnabled(uint index, bool enabled) external onlyOwner {
        require(index < transactions.length, "index must be in range of stored tx list");
        transactions[index].enabled = enabled;
    }

    /**
     * @return Number of transactions, both enabled and disabled, in transactions list.
     */
    function transactionsSize() external view returns (uint256) {
        return transactions.length;
    }

    /**
     * @dev wrapper to call the encoded transactions on downstream consumers.
     * @param destination Address of destination contract.
     * @param data The encoded data payload.
     * @return True on success
     */
    function externalCall(address destination, bytes memory data) internal returns (bool)
    {
        bool result;
        assembly {
            // "Allocate" memory for output
            // (0x40 is where "free memory" pointer is stored by convention)
            let outputAddress := mload(0x40)

            // First 32 bytes are the padded length of data, so exclude that
            let dataAddress := add(data, 32)

            result := call(
                // 34710 is the value that solidity is currently emitting
                // It includes callGas (700) + callVeryLow (3, to pay for SUB)
                // + callValueTransferGas (9000) + callNewAccountGas
                // (25000, in case the destination address does not exist and needs creating)
                sub(gas(), 34710),
                destination,
                0, // transfer value in wei
                dataAddress,
                mload(data),  // Size of the input, in bytes. Stored in position 0 of the array.
                outputAddress,
                0  // Output is ignored, therefore the output size is zero
            )
        }
        return result;
    }
}
/**
 * @dev Tollar token of ERC20 standard.
 * @author Over1 Team
 *
 * name           : Tollar
 * symbol         : TLR
 * decimal        : 9
 * basic supply   : 1,000,000 TLR
 */
function allowance(address owner_, address spender) public view override returns (uint256) {
    return _allowedFragments[owner_][spender];
}

/**
 * @dev Function to check the amount of tokens that an owner has allowed to a spender.
 * @param owner_ The address which owns the funds.
 * @param spender The address which will spend the funds.
 * @return The number of tokens still available for the spender.
 */