/***************************************************************************
 * gh_list.h -- a simple doubly-linked list implementation with a very     *
 * heavy focus on efficiency.                                              *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
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 ***************************************************************************/

/* $Id$ */

#ifndef GH_LIST_H
#define GH_LIST_H

#ifdef HAVE_CONFIG_H
#include "nsock_config.h"
#include "nbase_config.h"
#endif

#ifdef WIN32
#include "nbase_winconfig.h"
#endif

#include "error.h"
#include <assert.h>

#define GH_LIST_MAGIC 0xBADFACE

/* Take a LIST ELEMENT (not just the data) and return the next one */
#define GH_LIST_ELEM_NEXT(x)  ((x)->next)

/* Same as above but return the previous element */
#define GH_LIST_ELEM_PREV(x)  ((x)->prev)

/* Take a LIST (not a list element) and return the first element */
#define GH_LIST_FIRST_ELEM(x) ((x)->first)

/* Same as above but return the last element */
#define GH_LIST_LAST_ELEM(x)  ((x)->last)

/* Obtain the actual data stored in an element */
#define GH_LIST_ELEM_DATA(x)  ((x)->data)

/* Obtain the number of elements in a list */
#define GH_LIST_COUNT(x)      ((x)->count)


typedef struct gh_list_elem {
  void *data;
  struct gh_list_elem *next;
  struct gh_list_elem *prev;

  /* nonzero if this element was the first (or only) in a group that was
   * allocated.  This means we can safely free() it as long as we are OK with
   * freeing others that were freed with it ... */
  int allocated;

#ifndef NDEBUG
  unsigned long magic;
#endif
} gh_list_elem;

typedef struct gh_list {
  /* Number of elements in the list */
  int count;
  struct gh_list_elem *first;
  struct gh_list_elem *last;

  /* Instead of free()ing elements when something is removed from the list, we
   * stick them here for the next insert. */
  struct gh_list_elem *free;

  /* The number of list elements in the most recent malloc */
  int last_alloc;

#ifndef NDEBUG
  unsigned long magic;
#endif
} gh_list;


int gh_list_init(gh_list *newlist);

gh_list_elem *gh_list_append(gh_list *list, void *data);

gh_list_elem *gh_list_prepend(gh_list *list, void *data);

gh_list_elem *gh_list_insert_before(gh_list *list, gh_list_elem *before, void *data);

void *gh_list_pop(gh_list *list);

int gh_list_remove(gh_list *list, void *data);

int gh_list_free(gh_list *list);

int gh_list_move_front(gh_list *list, gh_list_elem *elem);

int gh_list_remove_elem(gh_list *list, gh_list_elem *elem);

#endif /* GH_LIST_H */