alcove

/* Copyright (c) 2014-2020, Michael Santos <michael.santos@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "alcove.h"

#include "alcove_call.h"

#include "alcove_calls.h"

ssize_t alcove_call(alcove_state_t *ap, u_int32_t call, const char *arg,
                    size_t len, char *reply, size_t rlen) {
  int index = 0;
  int arity = 0;
  int version = 0;

  const alcove_call_t *fun = NULL;
  ssize_t written = 0;

  uint8_t j;
  uint8_t k;

  if (call >= sizeof(calls) / sizeof(calls[0]))
    goto BADARG;

  j = call / 8;
  k = call % 8;

  if (ap->filter[j] & (1 << k))
    goto UNDEF;

  fun = &calls[call];

  /* minimum input in external term format
   * Magic:1/bytes, SmallTupleHeader:1/bytes, Arity:1/bytes
   * <<131,104,0>>
   */
  if (len < 4)
    goto BADARG;

  if (ei_decode_version(arg, &index, &version) < 0)
    goto BADARG;

  if (alcove_decode_tuple_header(arg, len, &index, &arity) < 0)
    goto BADARG;

  if (arity != fun->narg)
    goto BADARG;

  written = (*fun->fp)(ap, arg + index, len - index, reply, rlen);

  if (written < 0)
    goto BADARG;

  return written;

BADARG:
  return alcove_mk_atom(reply, rlen, "badarg");

UNDEF:
  return alcove_mk_atom(reply, rlen, "undef");
}