#include <stdio.h>
#include <string.h>
#include <openssl/evp.h>

unsigned char *base64_encode (unsigned char *buffer, unsigned int len)
{

  unsigned char *ret = (unsigned char *) malloc ((((len+2)/3)*4)+1);
  EVP_EncodeBlock (ret, buffer, len);
  ret[(((len+2)/3)*4)] = 0;
  return ret;
}

unsigned char *base64_decode (unsigned char *buffer, unsigned int len)
{

  unsigned char *ret = (unsigned char *) malloc ((((len+2)/3)*4)+1);
  EVP_DecodeBlock (ret, buffer, len);
  ret[(((len+2)/3)*4)] = 0;
  return ret;
}

void usage (char *progname) {

   printf ("Usage: %s [ encode | decode ] Text\n\n", progname);
   exit(0);
}

int main (int argc, char *argv[])
{
   int i;

   /* Sin parametros */
   if (argc < 3) usage(argv[0]);

   if (argc == 3) {

      /* Verificamos los algoritmos */
      if (strcmp(argv[1], "encode")  == 0)
         printf ("%s\n", base64_encode (argv[2], strlen(argv[2])));

      if (strcmp(argv[1], "decode") == 0)
         printf ("%s\n", base64_decode (argv[2], strlen(argv[2])));

   }
   else  usage(argv[0]);

   return 0;
}