libtomcrypt/demos/constants.c

/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#include "tomcrypt.h"

#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
#include <libgen.h>
#else
#define basename(x) x
#endif

/**
  @file demo_crypt_constants.c

  Demo how to get various constants to dynamic languages
  like Python

  Larry Bugbee, February 2013
*/

static void s_print_line(const char* cmd, const char* desc)
{
   printf("  %-16s - %s\n", cmd, desc);
}

int main(int argc, char **argv)
{
   if (argc == 1) {
      /* given a specific constant name, get and print its value */
      char name[] = "CTR_COUNTER_BIG_ENDIAN";
      int value;
      char *names_list;
      unsigned int names_list_len;

      if (crypt_get_constant(name, &value) != 0) exit(EXIT_FAILURE);
      printf("\n  %s is %d \n\n", name, value);

      /* get and print the length of the names (and values) list */

      if (crypt_list_all_constants(NULL, &names_list_len) != 0) exit(EXIT_FAILURE);
      printf("  need to allocate %u bytes \n\n", names_list_len);

      /* get and print the names (and values) list */
      if ((names_list = malloc(names_list_len)) == NULL) exit(EXIT_FAILURE);
      if (crypt_list_all_constants(names_list, &names_list_len) != 0) exit(EXIT_FAILURE);
      printf("  supported constants:\n\n%s\n\n", names_list);
      free(names_list);
   } else if (argc == 2) {
      if (strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) {
         char* base = strdup(basename(argv[0]));
         printf("Usage: %s [-a] [-s name]\n\n", base);
         s_print_line("<no argument>", "The old behavior of the demo");
         s_print_line("-a", "Only lists all constants");
         s_print_line("-s name", "List a single constant given as argument");
         s_print_line("-h", "The help you're looking at");
         free(base);
      } else if (strcmp(argv[1], "-a") == 0) {
         char *names_list;
         unsigned int names_list_len;
         /* get and print the length of the names (and values) list */
         if (crypt_list_all_constants(NULL, &names_list_len) != 0) exit(EXIT_FAILURE);
         /* get and print the names (and values) list */
         if ((names_list = malloc(names_list_len)) == NULL) exit(EXIT_FAILURE);
         if (crypt_list_all_constants(names_list, &names_list_len) != 0) exit(EXIT_FAILURE);
         printf("%s\n", names_list);
         free(names_list);
      }
   } else if (argc == 3) {
      if (strcmp(argv[1], "-s") == 0) {
         int value;
         if (crypt_get_constant(argv[2], &value) != 0) exit(EXIT_FAILURE);
         printf("%s,%u\n", argv[2], value);
      }
   }

   return 0;
}