pragma solidity ^0.8.4;

library ModexpPrecompile {
    /// @dev Computes (base ^ exponent) % modulus over big numbers.
    function modexp(
        bytes memory base,
        bytes memory exponent,
        bytes memory modulus
    ) internal view returns (bool success, bytes memory output) {
        bytes memory input = abi.encodePacked(
            uint256(base.length),
            uint256(exponent.length),
            uint256(modulus.length),
            base,
            exponent,
            modulus
        );

        output = new bytes(modulus.length);

        assembly {
            success := staticcall(
                gas(),
                5,
                add(input, 32),
                mload(input),
                add(output, 32),
                mload(modulus)
            )
        }
    }
}