Function statFile

cpp/ktools/ternktools.cpp:308–356

right now just used for timing

// right now just used for timing
static void statFile(int argc, const char** argv) {
    const char* filename = NULL;
    uint64_t iterations = 1;

    for (int i = 0; i < argc; i++) {
        if (std::string(argv[i]) == "-iterations") {
            if (i+1 >= argc) { badUsage("No argument after -iterations"); } i++;
            iterations = strtoull(argv[i], NULL, 0);
            if (iterations == ULLONG_MAX) {
                badUsage("Bad -iterations: %d (%s)", errno, strerror(errno));
            }
        } else {
            if (filename != NULL) { badUsage("Filename already specified: %s", filename); }
            filename = argv[i];
        }
    }

    printf("will stat %lu times\n", iterations);

    int64_t avg = 0;

    for (uint64_t i = 0; i < iterations; i++) {
        struct timespec ts0;
        clock_gettime(CLOCK_REALTIME, &ts0);

        {
            struct stat st;
            if(stat(filename, &st) != 0) {
                die("couldn't stat %s: %d (%s)", filename, errno, strerror(errno));
            }
        }
        struct timespec ts1;
        clock_gettime(CLOCK_REALTIME, &ts1);

        int64_t t0 = ts0.tv_sec * 1'000'000'000ull + ts0.tv_nsec;
        int64_t t1 = ts1.tv_sec * 1'000'000'000ull + ts1.tv_nsec;
        int64_t d = t1 - t0;

        printf("%lu:\t", i);
        printDelta(d);
        printf("\n");

        avg += d/iterations;
    }

    printf("avg:\t");
    printDelta(avg);
    printf("\n");
}

int main(int argc, const char** argv) {
    exe = argv[0];