Base64 Encoding and Decoding

base64.cpp

std::string base64_encode(const std::string& in) {
  BUF_MEM *bptr;
  BIO* b64 = BIO_new(BIO_f_base64());
  BIO* bio = BIO_new(BIO_s_mem());
  bio = BIO_push(b64, bio);
  BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);
  BIO_write(bio, in.c_str(), (int)in.size());
  BIO_flush(bio);
  BIO_get_mem_ptr(bio, &bptr);

  std::string out(bptr->data, bptr->length);
  BIO_free_all(bio);

  return out;
}

std::string base64_decode(const std::string& in) {
  BIO* b64 = BIO_new(BIO_f_base64());
  BIO* bio = BIO_new_mem_buf((void*)in.c_str(), in.size());
  bio = BIO_push(b64, bio);
  BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);

  std::string out(in.size(), 0);
  int len = BIO_read(bio, (void*)out.c_str(), out.size());
  out = out.substr(0, len);
  BIO_free_all(bio);

  return out;
}