/*
** Copyright (C) 2007 by Carnegie Mellon University.
**
** @OPENSOURCE_HEADER_START@
**
** Use of the SILK system and related source code is subject to the terms
** of the following licenses:
**
** GNU Public License (GPL) Rights pursuant to Version 2, June 1991
** Government Purpose License Rights (GPLR) pursuant to DFARS 252.225-7013
**
** NO WARRANTY
**
** ANY INFORMATION, MATERIALS, SERVICES, INTELLECTUAL PROPERTY OR OTHER
** PROPERTY OR RIGHTS GRANTED OR PROVIDED BY CARNEGIE MELLON UNIVERSITY
** PURSUANT TO THIS LICENSE (HEREINAFTER THE "DELIVERABLES") ARE ON AN
** "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY
** KIND, EITHER EXPRESS OR IMPLIED AS TO ANY MATTER INCLUDING, BUT NOT
** LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE,
** MERCHANTABILITY, INFORMATIONAL CONTENT, NONINFRINGEMENT, OR ERROR-FREE
** OPERATION. CARNEGIE MELLON UNIVERSITY SHALL NOT BE LIABLE FOR INDIRECT,
** SPECIAL OR CONSEQUENTIAL DAMAGES, SUCH AS LOSS OF PROFITS OR INABILITY
** TO USE SAID INTELLECTUAL PROPERTY, UNDER THIS LICENSE, REGARDLESS OF
** WHETHER SUCH PARTY WAS AWARE OF THE POSSIBILITY OF SUCH DAMAGES.
** LICENSEE AGREES THAT IT WILL NOT MAKE ANY WARRANTY ON BEHALF OF
** CARNEGIE MELLON UNIVERSITY, EXPRESS OR IMPLIED, TO ANY PERSON
** CONCERNING THE APPLICATION OF OR THE RESULTS TO BE OBTAINED WITH THE
** DELIVERABLES UNDER THIS LICENSE.
**
** Licensee hereby agrees to defend, indemnify, and hold harmless Carnegie
** Mellon University, its trustees, officers, employees, and agents from
** all claims or demands made against them (and any related losses,
** expenses, or attorney's fees) arising out of, or relating to Licensee's
** and/or its sub licensees' negligent use or willful misuse of or
** negligent conduct or willful misconduct regarding the Software,
** facilities, or other rights or assistance granted by Carnegie Mellon
** University under this License, including, but not limited to, any
** claims of product liability, personal injury, death, damage to
** property, or violation of any laws or regulations.
**
** Carnegie Mellon University Software Engineering Institute authored
** documents are sponsored by the U.S. Department of Defense under
** Contract F19628-00-C-0003. Carnegie Mellon University retains
** copyrights in all material produced under this contract. The U.S.
** Government retains a non-exclusive, royalty-free license to publish or
** reproduce these documents, or allow others to do so, for U.S.
** Government purposes only pursuant to the copyright license under the
** contract clause at 252.227.7013.
**
** @OPENSOURCE_HEADER_END@
*/
#ifndef _SKDLLIST_H
#define _SKDLLIST_H

#include "silk.h"

RCSIDENTVAR(rcsID_SKDLLIST_H, "$SiLK: skdllist.h 6904 2007-04-14 13:00:08Z mthomas $");

/*
**  skdllist.h
**
**  Doubly-linked lists
**
*/

struct _sk_dll_t;
struct _sk_dll_iter_t {
    void                  *data;
    struct _sk_dll_iter_t *link[2];
};

/*
 *    Signature of a doubly-linked list
 */
typedef struct _sk_dll_t      sk_dllist_t;

/*
 *    Signature of an iterator for a doubly linked list
 */
typedef struct _sk_dll_iter_t sk_dll_iter_t;


/*** Creation and destruction ***/

sk_dllist_t *skDLListCreate(void (*free_fn)(void *));
/*
 *    Creates a doubly-linked list for void *'s.  free_fn is a
 *    function used to free the inserted void *'s opon destruction of
 *    the lists, or NULL if they are not to be freed.  Returns the
 *    newly created empty list on success, and NULL if there is a
 *    memory allocation error.
 */

void skDLListDestroy(sk_dllist_t *list);
/*
 *    Destroys (and frees) a doubly-linked list.  Will use the
 *    'free-fn' passed into skDLListCreate to free any elements
 *    remaining in the list.
 */


/*** Info ***/

int skDLListIsEmpty(const sk_dllist_t *list);
/*
 *    Returns 1 if the given list is empty, 0 otherwise.
 */


/*** Deque operations ***/

int skDLListPeekTail(const sk_dllist_t *list, void **data);
/*
 *    Fills the pointer pointed to by 'data' with the pointer at the
 *    tail of the list.  Returns 0 if successful, -1 if empty.
 */

int skDLListPeekHead(const sk_dllist_t *list, void **data);
/*
 *    Fills the pointer pointed to by 'data' with the pointer at the
 *    head of the list.  Returns 0 if successful, -1 if empty.
 */

int skDLListPopTail(sk_dllist_t *list, void **data);
/*
 *    Fills the pointer pointed to by 'data' with the pointer at the
 *    tail of the list, and removes that element from the list.
 *    'data' may be NULL, in which case the pointer will not be
 *    returned.  Returns 0 if successful, -1 if empty.
 */

int skDLListPopHead(sk_dllist_t *list, void **data);
/*
 *    Fills the pointer pointed to by 'data' with the pointer at the
 *    head of the list, and removes that element from the list.
 *    'data' may be NULL, in which case the pointer will not be
 *    returned.  Returns 0 if successful, -1 if empty.
 */

int skDLListPushTail(sk_dllist_t *list, void *data);
/*
 *    Adds the pointer 'data' to the tail of the list.  Returns 0 if
 *    successful, -1 if there is a memory allocation error.
 */

int skDLListPushHead(sk_dllist_t *list, void *data);
/*
 *    Adds the pointer 'data' to the head of the list.  Returns 0 if
 *    successful, -1 if there is a memory allocation error.
 */


/*** Iterators ***/

void skDLLAssignIter(sk_dll_iter_t *iter, sk_dllist_t *list);
/*
 *    Assigns an already existing sk_dll_iter_t (iterator) to a list.
 *    The iterator starts out pointing to nothing.
 */

int skDLLIterDel(sk_dll_iter_t *iter);
/*
 *    Deletes the item the iterator is pointing to from its list.
 *    Afterward, the value is still pointed to by 'iter' and can be
 *    retrieved by skDLLIterValue().  The value pointed to by iter is
 *    not freed.  Returns 0 on success, -1 if the iterator isn't
 *    pointing to anything.
 */

int skDLLIterAddAfter(sk_dll_iter_t *iter, void *data);
/*
 *    Adds an element to the list 'iter' is referencing after the
 *    element pointed to by 'iter'.  If 'iter is pointing to nothing,
 *    it will be inserted at the head.  Returns 0 if successful, -1 if
 *    there is a memory allocation error.
 */

int skDLLIterAddBefore(sk_dll_iter_t *iter, void *data);
/*
 *    Adds an element to the list 'iter' is referencing before the
 *    element pointed to by 'iter'.  If 'iter is pointing to nothing,
 *    it will be inserted at the tail.  Returns 0 if successful, -1 if
 *    there is a memory allocation error.
 */

int skDLLIterForward(sk_dll_iter_t *iter, void **data);
/*
 *    Moves the iterator forward in the list, filling 'data' with the
 *    pointer 'iter' then points to.  If 'iter' is pointing to
 *    nothing, will move to the head of the list.  'data' may be NULL,
 *    in which case the pointer will not be returned.  If 'iter' is
 *    pointing at the tail of the list, iter will aftward point to
 *    nothing.  Returns 0 if successful, -1 if 'iter' was already at
 *    the tail of the list.
 */

int skDLLIterBackward(sk_dll_iter_t *iter, void **data);
/*
 *    Moves the iterator backward in the list, filling 'data' with the
 *    pointer 'iter' then points to.  If 'iter' is pointing to
 *    nothing, will move to the tail of the list.  'data' may be NULL,
 *    in which case the pointer will not be returned.  If 'iter' is
 *    pointing at the head of the list, iter will aftward point to
 *    nothing.  Returns 0 if successful, -1 if 'iter' was already at
 *    the head of the list.
 */

int skDLLIterValue(const sk_dll_iter_t *iter, void **data);
/*
 *    Fills the pointer pointed to by 'data' with the value pointed to
 *    by the iterator.  Returns 0 if successful, -1 if the iterator is
 *    pointing at nothing.
 */

#endif /* _SKDLLIST_H */


/*
** Local Variables:
** mode:c
** indent-tabs-mode:nil
** c-basic-offset:4
** End:
*/