int
eXosip_call_find_by_replaces (struct eXosip_t *excontext, char *replaces_str)
{
  eXosip_call_t *jc = NULL;
  eXosip_dialog_t *jd = NULL;
  char *call_id;
  char *to_tag;
  char *from_tag;
  char *early_flag;
  char *semicolon;
  char *totag_str = (char *) "to-tag=";
  char *fromtag_str = (char *) "from-tag=";
  char *earlyonly_str = (char *) "early-only";

  /* copy replaces string */
  if (replaces_str == NULL)
    return OSIP_SYNTAXERROR;
  call_id = osip_strdup (replaces_str);
  if (call_id == NULL)
    return OSIP_NOMEM;

  /* parse replaces string */
  to_tag = strstr (call_id, totag_str);
  from_tag = strstr (call_id, fromtag_str);
  early_flag = strstr (call_id, earlyonly_str);

  if ((to_tag == NULL) || (from_tag == NULL)) {
    osip_free (call_id);
    return OSIP_SYNTAXERROR;
  }
  to_tag += strlen (totag_str);
  from_tag += strlen (fromtag_str);

  while ((semicolon = strrchr (call_id, ';')) != NULL) {
    *semicolon = '\0';
  }

  for (jc = excontext->j_calls; jc != NULL; jc = jc->next) {
    for (jd = jc->c_dialogs; jd != NULL; jd = jd->next) {
      if (jd->d_dialog == NULL) {
        /* skip */
      }
      else if (((0 == strcmp (jd->d_dialog->call_id, call_id)) && (0 == strcmp (jd->d_dialog->remote_tag, to_tag)) && (0 == strcmp (jd->d_dialog->local_tag, from_tag)))
               || ((0 == strcmp (jd->d_dialog->call_id, call_id)) && (0 == strcmp (jd->d_dialog->local_tag, to_tag)) && (0 == strcmp (jd->d_dialog->remote_tag, from_tag)))) {
        /* This dialog match! */
        if (jd->d_dialog->state == DIALOG_CONFIRMED && early_flag != NULL) {
          osip_free (call_id);
          return OSIP_WRONG_STATE;      /* confirmed dialog but already answered with 486 */
        }
        if (jd->d_dialog->state == DIALOG_EARLY && jd->d_dialog->type == CALLEE) {
          osip_free (call_id);
          return OSIP_BADPARAMETER;     /* confirmed dialog but already answered with 481 */
        }

        osip_free (call_id);
        return jc->c_id;        /* match anyway */
      }
      // for calls in ringing-state only compare Call-ID and from-tag 
      // (contained in the from-tag field of the replaces-header !)
      // if the call had been forked, multiple different to-tags have been received 
      // by the caller in the 101..199 provisional responses
      else if (((0 == strcmp (jd->d_dialog->call_id, call_id)) && (0 == strcmp (jd->d_dialog->local_tag, to_tag)))
               || ((0 == strcmp (jd->d_dialog->call_id, call_id)) && (0 == strcmp (jd->d_dialog->remote_tag, to_tag)))) {
        /* This dialog match! */
        if (jd->d_dialog->state == DIALOG_CONFIRMED && early_flag != NULL) {
          osip_free (call_id);
          return OSIP_WRONG_STATE;      /* confirmed dialog but already answered with 486 */
        }

        osip_free (call_id);
        return jc->c_id;        /* match anyway */
      }
    }
  }
  osip_free (call_id);
  return OSIP_NOTFOUND;         /* answer with 481 */
}