Arithmetic.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.15;

import { SignedMath } from "@openzeppelin/contracts/utils/math/SignedMath.sol";
import { FixedPointMathLib } from "@rari-capital/solmate/src/utils/FixedPointMathLib.sol";

/**
 * @title Arithmetic
 * @notice Even more math than before.
 */
library Arithmetic {
    /**
     * @notice Clamps a value between a minimum and maximum.
     *
     * @param _value The value to clamp.
     * @param _min   The minimum value.
     * @param _max   The maximum value.
     *
     * @return The clamped value.
     */
    function clamp(
        int256 _value,
        int256 _min,
        int256 _max
    ) internal pure returns (int256) {
        return SignedMath.min(SignedMath.max(_value, _min), _max);
    }

    /**
     * @notice (c)oefficient (d)enominator (exp)onentiation function.
     *         Returns the result of: c * (1 - 1/d)^exp.
     *
     * @param _coefficient Coefficient of the function.
     * @param _denominator Fractional denominator.
     * @param _exponent    Power function exponent.
     *
     * @return Result of c * (1 - 1/d)^exp.
     */
    function cdexp(
        int256 _coefficient,
        int256 _denominator,
        int256 _exponent
    ) internal pure returns (int256) {
        return
            (_coefficient *
                (FixedPointMathLib.powWad(1e18 - (1e18 / _denominator), _exponent * 1e18))) / 1e18;
    }
}