a more geek function for the socket/recv in c

r_recv.c

char *imap_recv(int fd, size_t size) {
  size_t cursor = 0;
  int rc;

  char *buffer = (char *)malloc(sizeof(char)*size);
  char *result = (char *)malloc(sizeof(char)*size); 

  while (rc = recv(fd, buffer, size, 0)) {
    // if a message is less than the current size, it will return more data for fill in this pool. so I use \0 to avoid it.
    buffer[rc] = '\0';
    char *temp_str = buffer;
    char *temp_ptr = (char *)realloc(result, sizeof(char)*(cursor++)*size+rc);
    if (temp_ptr == NULL) {
      free(buffer);
      free(result);
      return NULL;
    }

    if (result != NULL) {
      strcpy(temp_ptr, result);
      strcat(temp_ptr, temp_str);
      result = temp_ptr;
    } else {
      strcpy(result, buffer);
    };

    // break
    if (rc < size) break;
  }
  
  free(buffer);
  return result;
}