/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#include "llist.h"

#ifdef DEBUGBUILD

#define LLISTINIT 0x100cc001 /* random pattern */

#define NODEINIT  0x12344321 /* random pattern */

#define NODEREM   0x54321012 /* random pattern */

#define VERIFYNODE(x) verifynode(x)

static struct Curl_llist_node *verifynode(struct Curl_llist_node *n)

{

  DEBUGASSERT(!n || (n->_init == NODEINIT));

  return n;

}

#else

#define VERIFYNODE(x) x

#endif

/*

 * @unittest 1300

 */

void Curl_llist_init(struct Curl_llist *l, Curl_llist_dtor dtor)

{

  l->_size = 0;

  l->_dtor = dtor;

  l->_head = NULL;

  l->_tail = NULL;

#ifdef DEBUGBUILD

  l->_init = LLISTINIT;

#endif

}

/*

 * Curl_llist_insert_next()

 *

 * Inserts a new list element after the given one 'e'. If the given existing

 * entry is NULL and the list already has elements, the new one will be

 * inserted first in the list.

 *

 * The 'ne' argument should be a pointer into the object to store.

 *

 * @unittest 1300

 */

void Curl_llist_insert_next(struct Curl_llist *list,

                            struct Curl_llist_node *e, /* may be NULL */

                            const void *p,

                            struct Curl_llist_node *ne)

{

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  DEBUGASSERT(ne);

#ifdef DEBUGBUILD

  ne->_init = NODEINIT;

#endif

  ne->_ptr = CURL_UNCONST(p);

  ne->_list = list;

  if(list->_size == 0) {

    list->_head = ne;

    list->_head->_prev = NULL;

    list->_head->_next = NULL;

    list->_tail = ne;

  }

  else {

    /* if 'e' is NULL here, we insert the new element first in the list */

    ne->_next = e ? e->_next : list->_head;

    ne->_prev = e;

    if(!e) {

      list->_head->_prev = ne;

      list->_head = ne;

    }

    else if(e->_next) {

      e->_next->_prev = ne;

    }

    else {

      list->_tail = ne;

    }

    if(e)

      e->_next = ne;

  }

  ++list->_size;

}

/*

 * Curl_llist_append()

 *

 * Adds a new list element to the end of the list.

 *

 * The 'ne' argument should be a pointer into the object to store.

 *

 * @unittest 1300

 */

void Curl_llist_append(struct Curl_llist *list, const void *p,

                       struct Curl_llist_node *ne)

{

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  DEBUGASSERT(ne);

  Curl_llist_insert_next(list, list->_tail, p, ne);

}

void *Curl_node_take_elem(struct Curl_llist_node *e)

{

  void *ptr;

  struct Curl_llist *list;

  if(!e)

    return NULL;

  list = e->_list;

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  DEBUGASSERT(list->_size);

  DEBUGASSERT(e->_init == NODEINIT);

  if(list) {

    if(e == list->_head) {

      list->_head = e->_next;

      if(!list->_head)

        list->_tail = NULL;

      else

        e->_next->_prev = NULL;

    }

    else {

      if(e->_prev)

        e->_prev->_next = e->_next;

      if(!e->_next)

        list->_tail = e->_prev;

      else

        e->_next->_prev = e->_prev;

    }

    --list->_size;

  }

  ptr = e->_ptr;

  e->_list = NULL;

  e->_ptr  = NULL;

  e->_prev = NULL;

  e->_next = NULL;

#ifdef DEBUGBUILD

  e->_init = NODEREM; /* specific pattern on remove - not zero */

#endif

  return ptr;

}

static void node_uremove(struct Curl_llist_node *e, void *user)

{

  struct Curl_llist *list;

  void *ptr;

  if(!e)

    return;

  list = e->_list;

  DEBUGASSERT(list);

  if(list) {

    ptr = Curl_node_take_elem(e);

    if(list->_dtor)

      list->_dtor(user, ptr);

  }

}

void Curl_node_remove(struct Curl_llist_node *e)

{

  node_uremove(e, NULL);

}

void Curl_llist_destroy(struct Curl_llist *list, void *user)

{

  if(list) {

    DEBUGASSERT(list->_init == LLISTINIT);

    while(list->_size > 0)

      node_uremove(list->_tail, user);

  }

}

/* Curl_llist_head() returns the first 'struct Curl_llist_node *', which

   might be NULL */

struct Curl_llist_node *Curl_llist_head(const struct Curl_llist *list)

{

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  return VERIFYNODE(list->_head);

}

#ifdef UNITTESTS

/* llist_tail() returns the last 'struct Curl_llist_node *', which might be

   NULL

   @unittest 1300

*/

UNITTEST struct Curl_llist_node *llist_tail(const struct Curl_llist *list);

UNITTEST struct Curl_llist_node *llist_tail(const struct Curl_llist *list)

{

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  return VERIFYNODE(list->_tail);

}

#endif

/* Curl_llist_count() returns a size_t the number of nodes in the list */

size_t Curl_llist_count(const struct Curl_llist *list)

{

  DEBUGASSERT(list);

  DEBUGASSERT(list->_init == LLISTINIT);

  return list->_size;

}

/* Curl_node_elem() returns the custom data from a Curl_llist_node */

void *Curl_node_elem(const struct Curl_llist_node *n)

{

  DEBUGASSERT(n);

  DEBUGASSERT(n->_init == NODEINIT);

  return n->_ptr;

}

/* Curl_node_next() returns the next element in a list from a given

   Curl_llist_node */

struct Curl_llist_node *Curl_node_next(const struct Curl_llist_node *n)

{

  DEBUGASSERT(n);

  DEBUGASSERT(n->_init == NODEINIT);

  return VERIFYNODE(n->_next);

}

#ifdef UNITTESTS

/* llist_node_prev() returns the previous element in a list from a given

   Curl_llist_node

   @unittest 1300

*/

UNITTEST struct Curl_llist_node *llist_node_prev(

  const struct Curl_llist_node *n);

UNITTEST struct Curl_llist_node *llist_node_prev(

  const struct Curl_llist_node *n)

{

  DEBUGASSERT(n);

  DEBUGASSERT(n->_init == NODEINIT);

  return VERIFYNODE(n->_prev);

}

#endif

struct Curl_llist *Curl_node_llist(const struct Curl_llist_node *n)

{

  DEBUGASSERT(n);

  DEBUGASSERT(!n->_list || n->_init == NODEINIT);

  return n->_list;

}