libsodium example

b2sum.c

#include <sodium.h>
#include <stdio.h>
#include <unistd.h>

#define BUFSIZE 65536
#define HASHSIZE 32

int main() {
  if (sodium_init() == -1) {
    return 1;
  }

  crypto_generichash_state state;
  crypto_generichash_init(&state, NULL, 0, HASHSIZE);

  unsigned char buf[BUFSIZE];
  ssize_t n;
  while ((n = read(STDIN_FILENO, buf, BUFSIZE))) {
    crypto_generichash_update(&state, buf, n);
  }

  unsigned char hash[HASHSIZE];
  crypto_generichash_final(&state, hash, HASHSIZE);

  char hex[2 * HASHSIZE + 1];
  sodium_bin2hex(hex, sizeof hex, hash, sizeof hash);

  printf("%s\n", hex);
}

gig.c

#include <sodium.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>

#define BUFSIZE 65536
#define HASHSIZE 32

#define INPUT_LEN 1000000000

void print_time(struct timespec tstart, struct timespec tend, char *name) {
  double diff = ((double)tend.tv_sec + 1.0e-9 * tend.tv_nsec) -
                ((double)tstart.tv_sec + 1.0e-9 * tstart.tv_nsec);
  printf("%.7fs %s\n", diff, name);
}

int main() {
  struct timespec tstart, tend;

  clock_gettime(CLOCK_MONOTONIC, &tstart);
  if (sodium_init() == -1) {
    return 1;
  }
  clock_gettime(CLOCK_MONOTONIC, &tend);
  print_time(tstart, tend, "init");

  clock_gettime(CLOCK_MONOTONIC, &tstart);
  unsigned char *input = calloc(INPUT_LEN, 1);
  clock_gettime(CLOCK_MONOTONIC, &tend);
  print_time(tstart, tend, "calloc");

  clock_gettime(CLOCK_MONOTONIC, &tstart);
  for (int i = 0; i < INPUT_LEN; i++) {
    if (input[i] != 0) {
      printf("PANIC!\n");
    }
  }
  clock_gettime(CLOCK_MONOTONIC, &tend);
  print_time(tstart, tend, "read");

  clock_gettime(CLOCK_MONOTONIC, &tstart);
  unsigned char hash[HASHSIZE];
  crypto_generichash(hash, HASHSIZE, input, INPUT_LEN, NULL, 0);
  clock_gettime(CLOCK_MONOTONIC, &tend);
  print_time(tstart, tend, "hash");

  char hex[2 * HASHSIZE + 1];
  sodium_bin2hex(hex, sizeof hex, hash, sizeof hash);

  printf("%s\n", hex);
}