Function main

dev/json_migration_bench/parse_bench.cpp:44–96

}

int main(int argc, char** argv) {
    const char* path = (argc > 1) ? argv[1] : "dev/all_fluids.json";
    std::string s = read_file(path);
    std::printf("file: %s   size: %.2f MB\n\n", path, s.size() / (1024.0 * 1024.0));

    const int iters = 15;

    // RapidJSON full DOM parse (matches the loaders' d.Parse<0>(...) usage).
    run("rapidjson", iters, [&] {
        rapidjson::Document d;
        d.Parse<0>(s.c_str());
        if (d.HasParseError()) {
            std::fprintf(stderr, "rapidjson parse error\n");
            std::abort();
        }
    });

    // nlohmann full DOM parse.
    run("nlohmann-json", iters, [&] {
        auto j = nlohmann::json::parse(s);
        if (!j.is_array() && !j.is_object()) {
            std::fprintf(stderr, "nlohmann parse error\n");
            std::abort();
        }
    });

    // Mitigation: pre-parsed binary blobs (nlohmann reads these natively and
    // much faster than text JSON). Generate once from the parsed doc, then
    // time deserialization — this is what a CBOR/MessagePack-embedded build
    // would pay at first load.
    nlohmann::json doc = nlohmann::json::parse(s);
    std::vector<std::uint8_t> mp = nlohmann::json::to_msgpack(doc);
    std::vector<std::uint8_t> cb = nlohmann::json::to_cbor(doc);
    std::printf("\nbinary blob sizes:  msgpack %.2f MB   cbor %.2f MB   (json text %.2f MB)\n\n", mp.size() / (1024.0 * 1024.0),
                cb.size() / (1024.0 * 1024.0), s.size() / (1024.0 * 1024.0));

    run("nlohmann-mpack", iters, [&] {
        auto j = nlohmann::json::from_msgpack(mp);
        if (!j.is_array() && !j.is_object()) {
            std::fprintf(stderr, "msgpack error\n");
            std::abort();
        }
    });
    run("nlohmann-cbor", iters, [&] {
        auto j = nlohmann::json::from_cbor(cb);
        if (!j.is_array() && !j.is_object()) {
            std::fprintf(stderr, "cbor error\n");
            std::abort();
        }
    });

    return 0;
}