library SignedDecimal {
    using SignedDecimalMath for int256;
    using SignedSafeMath for int256;

    struct signedDecimal {
        int256 d;
    }

    function zero() internal pure returns (signedDecimal memory) {
        return signedDecimal(0);
    }

    function toInt(signedDecimal memory x) internal pure returns (int256) {
        return x.d;
    }

    function isNegative(signedDecimal memory x) internal pure returns (bool) {
        if (x.d < 0) {
            return true;
        }
        return false;
    }

    function abs(signedDecimal memory x) internal pure returns (Decimal.decimal memory) {
        Decimal.decimal memory t;
        if (x.d < 0) {
            t.d = uint256(0 - x.d);
        } else {
            t.d = uint256(x.d);
        }
        return t;
    }

    /// @dev add two decimals
    function addD(signedDecimal memory x, signedDecimal memory y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.add(y.d);
        return t;
    }

    /// @dev subtract two decimals
    function subD(signedDecimal memory x, signedDecimal memory y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.sub(y.d);
        return t;
    }

    /// @dev multiple two decimals
    function mulD(signedDecimal memory x, signedDecimal memory y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.muld(y.d);
        return t;
    }

    /// @dev multiple a signedDecimal by a int256
    function mulScalar(signedDecimal memory x, int256 y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.mul(y);
        return t;
    }

    /// @dev divide two decimals
    function divD(signedDecimal memory x, signedDecimal memory y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.divd(y.d);
        return t;
    }

    /// @dev divide a signedDecimal by a int256
    function divScalar(signedDecimal memory x, int256 y) internal pure returns (signedDecimal memory) {
        signedDecimal memory t;
        t.d = x.d.div(y);
        return t;
    }
}
function mulD(signedDecimal memory x, signedDecimal memory y) internal pure returns (signedDecimal memory) {
    signedDecimal memory t;
    t.d = x.d.muld(y.d);
    return t;
}

/// @dev multiple two decimals