fortuna/urandom_entropy_src.h

#ifndef FORTUNA_URANDOM_ENTROPY_SRC_H
#define FORTUNA_URANDOM_ENTROPY_SRC_H

#include "entropy_src.h"

#include <fmt/core.h>
#include <fstream>

namespace fortuna {
namespace accumulator {

class UrandomEntropySrc : public EntropySrc {
public:
	static constexpr const std::size_t max_event_length{32};

	auto schedule(accumulator::EventScheduler scheduler) -> void {
		scheduler.schedule(std::chrono::milliseconds(100));
	}

	auto event(accumulator::EventAdder adder) -> void {
		std::ifstream file;
		file.exceptions(std::ifstream::failbit | std::ifstream::badbit);

		try {
			std::ifstream urandom("/dev/urandom",
								  std::ios::in | std::ios::binary);
			// check if stream is open
			if (urandom) {
				urandom.read(reinterpret_cast<char*>(&bytes), bytes.length());
				urandom.close();
			}
			else {
				// open failed
				fmt::print(stderr, "Failed to open /dev/urandom\n");
			}
		}
		catch (std::ifstream::failure& e) {
			fmt::print("io exception caugth: {}\n", e.what());
		}
	}

	auto urandom_entropy_src_service() -> int;

private:
	static std::vector<char> bytes[max_event_length];
};

} // namespace accumulator
} // namespace fortuna
#endif // FORTUNA_URANDOM_ENTROPY_SRC_H