Defi Lending Concepts 1

ctokenexchange.sol

pragma solidity ^0.8.13;

function exchangeRateStoredInternal() internal view returns (MathError, uint) {
    uint _totalSupply = totalSupply;
    if (_totalSupply == 0) {
        return (MathError.NO_ERROR, initialExchangeRateMantissa);
    } else {
        uint totalCash = getCashPrior();
        uint cashPlusBorrowsMinusReserves;
        Exp memory exchangeRate;
        MathError mathErr;

        (mathErr, cashPlusBorrowsMinusReserves) = addThenSubUInt(totalCash, totalBorrows, totalReserves);
        if (mathErr != MathError.NO_ERROR) {
            return (mathErr, 0);
        }

        (mathErr, exchangeRate) = getExp(cashPlusBorrowsMinusReserves, _totalSupply);
        if (mathErr != MathError.NO_ERROR) {
            return (mathErr, 0);
        }

        return (MathError.NO_ERROR, exchangeRate.mantissa);
    }
}