/*

 * Feature-Caps header field body parser

 *

 * Copyright (c) 2020 OpenSIPS Solutions

 *

 * This file is part of opensips, a free SIP server.

 *

 * opensips is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version

 *

 * opensips is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "../mem/mem.h"

#include "../ut.h"

#include "parse_fcaps.h"

static str fcaps_pns = str_init("+sip.pns");

/* Feature-Caps: +sip.pns="apns";+sip.pnsreg="130" */

int parse_fcaps(struct hdr_field* _h)

{

  fcaps_body_t *b = NULL;

  int len = _h->body.len;

  char *s = _h->body.s, *end = s + len, *p;

  if (_h->parsed)

    return 0;

  /* optimized, simplistic parser.  Ideal for the PN proxy use case! */

  while (len > 0 && (p = q_memchr(s, '+', len))) {

    len -= p + 1 - s;

    s = p + 1;

    if (end - p >= (fcaps_pns.len + 4) &&

            !memcmp(p, fcaps_pns.s, fcaps_pns.len)) {

      p += fcaps_pns.len;

      len -= p - s;

      s = p;

      /* start LDQUOT */

      if (*p != '=' || *(p + 1) != '"')

        continue;

      /* end LDQUOT */

      p += 2;

      len -= 2;

      s = p;

      if (!(p = q_memchr(s + 1, '"', len - 1)))

        goto out;

      /* successfully matched a +sip.pns="..." string */

      if (!b) {

        b = pkg_malloc(sizeof *b);

        if (!b) {

          LM_ERR("oom\n");

          return -1;

        }

        memset(b, 0, sizeof *b);

      }

      b->pns.s = s;

      b->pns.len = p - s;

      p++;

      len -= p - s;

      s = p;

    }

  }

out:

  if (!b)

    return -1;

  _h->parsed = (void *)b;

  return 0;

}

void free_fcaps(fcaps_body_t** _fc)

{

  pkg_free(*_fc);

  *_fc = NULL;

}