Sha hash function operation using OpenSSL library

openssl_sha.c

// https://dvtalk.me

#ifndef __SHA_HASH_C__
#define __SHA_HASH_C__
#include <openssl/conf.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>


#ifndef __MAIN__
#define __MAIN__

int main (void) {

  unsigned char *hashmessage = (unsigned char *)"If there was an abundance of misery in the world, there was also sufficient joy, yes - as long as one knew where to look for it.";


  unsigned int hashcode_len;
  unsigned char hashcode[4096];

  hashcode_len = sha_digest(SHA_384,
        hashmessage,
        strlen((char *)hashmessage),
        hashcode);

  /* Clean up */
  EVP_cleanup();
  ERR_free_strings();

  return 0;
}
#endif

#ifndef __HANDLE_ERRORS__
#define __HANDLE_ERRORS__
void handleErrors(void) {
  ERR_print_errors_fp(stderr);
  abort();
}
#endif

unsigned int sha_digest(enum SHA_OP_MODE sha_mode,
      unsigned char *plaintext, 
      int plaintext_len,
      unsigned char *hashcode) {

   /* Initialise the library */
   ERR_load_crypto_strings();
   OpenSSL_add_all_digests();
   //   OPENSSL_config(NULL);

   const EVP_MD *hashptr;
   unsigned int hashcode_len;

   switch (sha_mode) {
      case SHA_1:       if ((hashptr = EVP_sha1())       == NULL) handleErrors(); break;
      case SHA_224:     if ((hashptr = EVP_sha224())     == NULL) handleErrors(); break;
      case SHA_256:     if ((hashptr = EVP_sha256())     == NULL) handleErrors(); break;
      case SHA_384:     if ((hashptr = EVP_sha384())     == NULL) handleErrors(); break;
      case SHA_512:     if ((hashptr = EVP_sha512())     == NULL) handleErrors(); break;
      case SHA_512_224: if ((hashptr = EVP_sha512_224()) == NULL) handleErrors(); break;
      case SHA_512_256: if ((hashptr = EVP_sha512_256()) == NULL) handleErrors(); break;
      default:          if ((hashptr = EVP_sha1())       == NULL) handleErrors(); break;
   }

   EVP_MD_CTX *hashctx = EVP_MD_CTX_create();
   EVP_DigestInit_ex(hashctx, hashptr, NULL);

   EVP_DigestUpdate(hashctx, plaintext, plaintext_len);
   EVP_DigestFinal_ex(hashctx, hashcode, &hashcode_len);

   EVP_MD_CTX_destroy(hashctx);

   printf("\nPlain text length:%d bytes \nPlaintext is:\n", plaintext_len);
   BIO_dump_fp (stdout, (const char *)plaintext, plaintext_len);

   printf("\nHash code length:%d bytes \nHashcode is:\n", hashcode_len);
   BIO_dump_fp (stdout, (const char *)hashcode, hashcode_len);


   return hashcode_len;

}

#endif