xref: /freebsd/sys/dev/isci/scil/sci_abstract_list.h (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of version 2 of the GNU General Public License as
13  * published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
23  * The full GNU General Public License is included in this distribution
24  * in the file called LICENSE.GPL.
25  *
26  * BSD LICENSE
27  *
28  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
29  * All rights reserved.
30  *
31  * Redistribution and use in source and binary forms, with or without
32  * modification, are permitted provided that the following conditions
33  * are met:
34  *
35  *   * Redistributions of source code must retain the above copyright
36  *     notice, this list of conditions and the following disclaimer.
37  *   * Redistributions in binary form must reproduce the above copyright
38  *     notice, this list of conditions and the following disclaimer in
39  *     the documentation and/or other materials provided with the
40  *     distribution.
41  *
42  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
43  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
44  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
45  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
46  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
47  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
48  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
49  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
50  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
51  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
52  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
53  */
54 /**
55  * @file
56  *
57  * @brief This file contains the interface to the abstract list class.
58  *        This class will allow for the same item to occur multiple times in
59  *        a list or multiple lists.  It will provide an interface that is
60  *        similar to the C++ standard template list interface.
61  *        Methods Provided:
62  *        - sci_abstract_list_front()
63  *        - sci_abstract_list_back()
64  *        - sci_abstract_list_is_empty()
65  *        - sci_abstract_list_size()
66  *        - sci_abstract_list_print()
67  *        - sci_abstract_list_find()
68  *        - sci_abstract_list_popback()
69  *        - sci_abstract_list_popfront()
70  *        - sci_abstract_list_erase()
71  *        - sci_abstract_list_pushback()
72  *        - sci_abstract_list_pushfront()
73  *        - sci_abstract_list_get_object()
74  *        - sci_abstract_list_get_next()
75  *        - sci_abstract_list_insert() UNIMPLEMENTED
76  *        - sci_abstract_list_clear()
77  */
78 
79 #ifndef _SCI_ABSTRACT_LIST_H_
80 #define _SCI_ABSTRACT_LIST_H_
81 
82 //******************************************************************************
83 //*
84 //*     I N C L U D E S
85 //*
86 //******************************************************************************
87 
88 #include <dev/isci/scil/sci_types.h>
89 
90 //******************************************************************************
91 //*
92 //*     C O N S T A N T S
93 //*
94 //******************************************************************************
95 
96 //******************************************************************************
97 //*
98 //*     T Y P E S
99 //*
100 //******************************************************************************
101 
102 /**
103  * @struct SCI_ABSTRACT_ELEMENT
104  *
105  * @brief This object represents an element of a abstract list.
106  *        NOTE: This structure does not evenly align on a cache line
107  *              boundary.  If SSP specific code ends up using this list,
108  *              then it may be a good idea to force the alignment.  Now
109  *              it is more important to save the space.
110  */
111 typedef struct SCI_ABSTRACT_ELEMENT
112 {
113    /**
114     * This field points to the next item in the abstract_list.
115     */
116    struct SCI_ABSTRACT_ELEMENT * next_p;
117 
118    /**
119     * This field points to the previous item in the abstract_list.
120     */
121    struct SCI_ABSTRACT_ELEMENT * previous_p;
122 
123    /**
124     * This field points to the object the list is managing (i.e. the thing
125     * being listed).
126     */
127    void * object_p;
128 
129 } SCI_ABSTRACT_ELEMENT_T;
130 
131 /**
132  * @struct SCI_ABSTRACT_ELEMENT_LIST
133  *
134  * @brief This object represents an element list object.  It can have
135  *        elements added and removed from it.
136  */
137 typedef struct SCI_ABSTRACT_ELEMENT_LIST
138 {
139    /**
140     * Pointer to the front (head) of the list.
141     */
142    SCI_ABSTRACT_ELEMENT_T * front_p;
143 
144    /**
145     * Pointer to the back (tail) of the list.
146     */
147    SCI_ABSTRACT_ELEMENT_T * back_p;
148 
149    /**
150     * This field depicts the number of elements in this list.
151     * NOTE: It is possible to remove this field and replace it with a
152     *       linear walking of the list to determine the size, but since
153     *       there aren't many lists in the system we don't utilize much
154     *       space.
155     */
156    U32 size;
157 
158 } SCI_ABSTRACT_ELEMENT_LIST_T;
159 
160 /**
161  * @struct SCI_ABSTRACT_ELEMENT_POOL
162  *
163  * @brief This structure provides the pool of free abstract elements to be
164  *        utilized by an SCI_ABSTRACT_LIST.
165  */
166 typedef struct SCI_ABSTRACT_ELEMENT_POOL
167 {
168    /**
169     * Pointer to an array of elements to be managed by this pool.  This
170     * array acts as the memory store for the elements in the free pool or
171     * allocated out of the pool into an SCI_ABSTRACT_LIST.
172     */
173    SCI_ABSTRACT_ELEMENT_T * elements;
174 
175    /**
176     * This field contains the maximum number of free elements for the pool.
177     * It is set at creation of the pool and should not be changed afterward.
178     */
179    U32 max_elements;
180 
181    /**
182     * Pointer to the list of free elements that can be allocated from
183     * the pool.
184     */
185    struct SCI_ABSTRACT_ELEMENT_LIST  free_list;
186 
187 } SCI_ABSTRACT_ELEMENT_POOL_T;
188 
189 /**
190  * @struct SCI_ABSTRACT_LIST
191  *
192  * @brief This object provides the ability to queue any type of object or
193  *        even the same object multiple times.  The object must be provided
194  *        an element pool from which to draw free elements.
195  */
196 typedef struct SCI_ABSTRACT_LIST
197 {
198    /**
199     * This represents the elements currently managed by the list.
200     */
201    SCI_ABSTRACT_ELEMENT_LIST_T  elements;
202 
203    /**
204     * This field contains elements that are currently available for
205     * allocation into the list of elements;
206     */
207    SCI_ABSTRACT_ELEMENT_POOL_T * free_pool;
208 
209 } SCI_ABSTRACT_LIST_T;
210 
211 //******************************************************************************
212 //*
213 //*     P R O T E C T E D   M E T H O D S
214 //*
215 //******************************************************************************
216 
217 void sci_abstract_element_pool_construct(
218    SCI_ABSTRACT_ELEMENT_POOL_T * pool,
219    SCI_ABSTRACT_ELEMENT_T      * list_elements,
220    int                           element_count
221 );
222 
223 void sci_abstract_list_construct(
224    SCI_ABSTRACT_LIST_T         * list,
225    SCI_ABSTRACT_ELEMENT_POOL_T * free_pool
226 );
227 
228 
229 
230 #ifdef USE_ABSTRACT_LIST_FUNCTIONS
231 //******************************************************************************
232 //*
233 //*     P U B L I C   M E T H O D S
234 //*
235 //******************************************************************************
236 
237 /**
238  * Simply return the front element pointer of the list.  This returns an element
239  * element as opposed to what the element is pointing to.
240  */
241 SCI_ABSTRACT_ELEMENT_T * sci_abstract_list_get_front(
242    SCI_ABSTRACT_LIST_T * list_p
243 );
244 
245 
246 /**
247  * This method simply returns the object pointed to by the head (front) of
248  * the list.
249  */
250 void * sci_abstract_list_front(
251    SCI_ABSTRACT_LIST_T * list_p
252 );
253 
254 
255 /**
256  * This method simply returns the object pointed to by the tail (back) of
257  * the list.
258  */
259 void * sci_abstract_list_back(
260    SCI_ABSTRACT_LIST_T * list_p
261 );
262 
263 
264 /**
265  * This method will return FALSE if the list is not empty.
266  */
267 BOOL sci_abstract_list_is_empty(
268    SCI_ABSTRACT_LIST_T * list_p
269 );
270 
271 
272 /**
273  * This method will return the number of elements queued in the list.
274  */
275 U32 sci_abstract_list_size(
276    SCI_ABSTRACT_LIST_T * list_p
277 );
278 
279 
280 /**
281  * This method simply returns the next list element in the list.
282  */
283 SCI_ABSTRACT_ELEMENT_T * sci_abstract_list_get_next(
284    SCI_ABSTRACT_ELEMENT_T * alElement_p
285 );
286 
287 
288 /**
289  * This method simply prints the contents of the list.
290  */
291 void  sci_abstract_list_print(
292    SCI_ABSTRACT_LIST_T * list_p
293 );
294 
295 
296 /**
297  * This method will simply search the supplied list for the desired object.
298  * It will return a pointer to the object, if it is found.  Otherwise
299  * it will return NULL.
300  */
301 void * sci_abstract_list_find(
302    SCI_ABSTRACT_LIST_T * list_p,
303    void * obj_p
304 );
305 
306 
307 /**
308  * This method will simply remove the element at the back (tail) of the list.
309  * It will return a pointer to the object that was removed or NULL if not
310  * found.
311  */
312 void * sci_abstract_list_popback(
313    SCI_ABSTRACT_LIST_T * list_p
314 );
315 
316 
317 /**
318  * This method simply removes the list element at the head of the list
319  * and returns the pointer to the object that was removed.
320  */
321 void * sci_abstract_list_popfront(
322    SCI_ABSTRACT_LIST_T * list_p
323 );
324 
325 
326 
327 /**
328  * This method will erase (remove) all instances of the supplied object from
329  * anywhere in the list.
330  */
331 void sci_abstract_list_erase(
332    SCI_ABSTRACT_LIST_T * list_p,
333    void * obj_p
334 );
335 
336 
337 /**
338  * This method simply adds a LIST_ELEMENT for the supplied object to the back
339  * (tail) of the supplied list.
340  */
341 void sci_abstract_list_pushback(
342    SCI_ABSTRACT_LIST_T * list_p,
343    void * obj_p
344 );
345 
346 
347 
348 /**
349  * This method simply adds a LIST_ELEMENT for the supplied object to the front
350  * (head) of the supplied list.
351  */
352 void sci_abstract_list_pushfront(
353    SCI_ABSTRACT_LIST_T * list_p,
354    void * obj_p
355 );
356 
357 
358 /**
359  * This method will add the objToAdd_p object to the list before the obj_p.
360  * NOTE: UNIMPLEMENTED
361  */
362 void sci_abstract_list_insert(
363    SCI_ABSTRACT_LIST_T * list_p,
364    void * obj_p,
365    void * objToAdd_p
366 );
367 
368 
369 /**
370  * This method simply frees all the items from the list.
371  */
372 void sci_abstract_list_clear(
373    SCI_ABSTRACT_LIST_T * list_p
374 );
375 
376 
377 /**
378  * This method simply returns the object being pointed to by the list element
379  * (The item being listed).
380  */
381 void * sci_abstract_list_get_object(
382    SCI_ABSTRACT_ELEMENT_T * alElement_p
383 );
384 
385 
386 /**
387  * This method is simply a wrapper to provide the number of elements in
388  * the free list.
389  */
390 U32 sci_abstract_list_freeList_size(
391    SCI_ABSTRACT_LIST_T * freeList
392 );
393 
394 
395 //******************************************************************************
396 //*
397 //*     P R I V A T E   M E T H O D S
398 //*
399 //******************************************************************************
400 
401 /**
402  * This method simply performs the common portion of pushing a list element
403  * onto a list.
404  *
405  * WARNING: This is a private helper method that should not be called directly
406  *          by any users.
407  */
408 void private_push_front(
409    SCI_ABSTRACT_ELEMENT_LIST_T * privateList_p,
410    SCI_ABSTRACT_ELEMENT_T * alElement_p
411 );
412 
413 
414 /**
415  * This method simply performs the common portion of popping a list element
416  * from a list.
417  *
418  * WARNING: This is a private helper method that should not be called directly
419  *          by any users.
420  */
421 SCI_ABSTRACT_ELEMENT_T * private_pop_front(
422    SCI_ABSTRACT_ELEMENT_LIST_T * privateList_p
423 );
424 
425 
426 /**
427  * This method will simply search the supplied list for the desired object.
428  * It will return a pointer to the abstract_list_element if found, otherwise
429  * it will return NULL.
430  */
431 SCI_ABSTRACT_ELEMENT_T * private_find(
432    SCI_ABSTRACT_ELEMENT_LIST_T * list_p,
433    void * obj_p
434 );
435 
436 
437 /**
438  * This private method will free the supplied list element back to the pool
439  * of free list elements.
440  */
441 void private_pool_free(
442    SCI_ABSTRACT_ELEMENT_POOL_T * free_pool,
443    SCI_ABSTRACT_ELEMENT_T * alElement_p
444 );
445 
446 
447 /**
448  * This private method will allocate a list element from the pool of free
449  * list elements.
450  */
451 SCI_ABSTRACT_ELEMENT_T * private_pool_allocate(
452    SCI_ABSTRACT_ELEMENT_POOL_T * free_pool
453 );
454 
455 
456 #else
457 
458 //******************************************************************************
459 //*
460 //*     P U B L I C   M E T H O D S
461 //*
462 //******************************************************************************
463 
464 /**
465  * Simply return the front element pointer of the list.  This returns an element
466  * element as opposed to what the element is pointing to.
467  */
468 #define sci_abstract_list_get_front(                                           \
469    list_p                                                                      \
470 )                                                                              \
471 ((list_p)->elements.front_p)
472 
473 /**
474  * This method simply returns the object pointed to by the head (front) of
475  * the list.
476  */
477 #define sci_abstract_list_front(                                               \
478    list_p                                                                      \
479 )                                                                              \
480 ( ( (list_p)->elements.front_p ) ? ((list_p)->elements.front_p->object_p) : NULL )
481 
482 /**
483  * This method simply returns the object pointed to by the tail (back) of
484  * the list.
485  */
486 #define sci_abstract_list_back(                                                \
487    list_p                                                                      \
488 )                                                                              \
489 ( ( (list_p)->elements.back_p ) ? ((list_p)->elements.back_p->object_p) : NULL )
490 
491 /**
492  * This method will return FALSE if the list is not empty.
493  */
494 #define sci_abstract_list_is_empty(                                            \
495    list_p                                                                      \
496 )                                                                              \
497 ( (list_p)->elements.front_p == NULL )
498 
499 /**
500  * This method will return the number of elements queued in the list.
501  */
502 #define sci_abstract_list_size(                                                \
503    list_p                                                                      \
504 )                                                                              \
505 ( (list_p)->elements.size )
506 
507 /**
508  * This method simply returns the next list element in the list.
509  */
510 #define sci_abstract_list_get_next(                                            \
511    alElement_p                                                                 \
512 )                                                                              \
513 ( (alElement_p)->next_p )
514 
515 /**
516  * This method simply prints the contents of the list.
517  */
518 #define sci_abstract_list_print(                                               \
519    list_p                                                                      \
520 )                                                                              \
521 {                                                                              \
522    SCI_ABSTRACT_ELEMENT_T * alElement_p = list_p->elements.front_p;            \
523                                                                                \
524    while (alElement_p != NULL)                                                 \
525    {                                                                           \
526       /* Check to see if we found the object for which we are searching. */    \
527       printf("ITEM next_p 0x%x prev_p 0x%x obj_p 0x%x, 0x%x\n",                \
528              alElement_p->next_p,                                              \
529              alElement_p->previous_p,                                          \
530              (U32*) (alElement_p->object_p));                                  \
531                                                                                \
532       alElement_p = alElement_p->next_p;                                       \
533    }                                                                           \
534 }
535 
536 /**
537  * This method will simply search the supplied list for the desired object.
538  * It will return a pointer to the object, if it is found.  Otherwise
539  * it will return NULL.
540  */
541 #define sci_abstract_list_find(                                                \
542    list_p,                                                                     \
543    obj_p                                                                       \
544 )                                                                              \
545 ({                                                                             \
546    sci_abstract_list_get_object(private_find(&(list_p)->elements, (obj_p)));   \
547 })
548 
549 /**
550  * This method will simply remove the element at the back (tail) of the list.
551  * It will return a pointer to the object that was removed or NULL if not
552  * found.
553  */
554 #define sci_abstract_list_popback(                                             \
555    list_p                                                                      \
556 )                                                                              \
557 ({                                                                             \
558    SCI_ABSTRACT_ELEMENT_LIST_T * elem_list = &(list_p)->elements;              \
559    SCI_ABSTRACT_ELEMENT_T      * alElement_p = elem_list->back_p;              \
560    void * obj_p = NULL;                                                        \
561                                                                                \
562    if (alElement_p != NULL)                                                    \
563    {                                                                           \
564       obj_p = alElement_p->object_p;                                           \
565       if (elem_list->back_p == elem_list->front_p)                             \
566       {                                                                        \
567          elem_list->back_p = elem_list->front_p = NULL;                        \
568       }                                                                        \
569       else                                                                     \
570       {                                                                        \
571          elem_list->back_p = elem_list->back_p->previous_p;                    \
572          elem_list->back_p->next_p = NULL;                                     \
573       }                                                                        \
574                                                                                \
575       elem_list->size--;                                                       \
576       private_pool_free((list_p)->free_pool, alElement_p);                     \
577    }                                                                           \
578                                                                                \
579    obj_p;                                                                      \
580 })
581 
582 /**
583  * This method simply removes the list element at the head of the list
584  * and returns the pointer to the object that was removed.
585  */
586 #define sci_abstract_list_popfront(                                            \
587    list_p                                                                      \
588 )                                                                              \
589 ({                                                                             \
590    SCI_ABSTRACT_ELEMENT_T * alElement_p =                                      \
591                               private_pop_front(&(list_p)->elements);          \
592    void * obj_p = NULL;                                                        \
593                                                                                \
594    if (alElement_p != NULL)                                                    \
595    {                                                                           \
596       obj_p = alElement_p->object_p;                                           \
597       private_pool_free((list_p)->free_pool, alElement_p);                     \
598    }                                                                           \
599                                                                                \
600    obj_p;                                                                      \
601 })
602 
603 /**
604  * This method will erase (remove) all instances of the supplied object from
605  * anywhere in the list.
606  */
607 #define sci_abstract_list_erase(                                               \
608    list_p,                                                                     \
609    obj_p                                                                       \
610 )                                                                              \
611 {                                                                              \
612    SCI_ABSTRACT_ELEMENT_LIST_T * elem_list = &(list_p)->elements;              \
613    SCI_ABSTRACT_ELEMENT_T      * alElement_p;                                  \
614                                                                                \
615    while ((alElement_p = private_find(elem_list, (obj_p))) != NULL)            \
616    {                                                                           \
617       if (alElement_p == elem_list->front_p)                                   \
618       {                                                                        \
619          sci_abstract_list_popfront(list_p);                                   \
620       }                                                                        \
621       else if (alElement_p == elem_list->back_p)                               \
622       {                                                                        \
623          sci_abstract_list_popback(list_p);                                    \
624       }                                                                        \
625       else                                                                     \
626       {                                                                        \
627          alElement_p->previous_p->next_p = alElement_p->next_p;                \
628          alElement_p->next_p->previous_p = alElement_p->previous_p;            \
629          elem_list->size--;                                                    \
630          private_pool_free((list_p)->free_pool, alElement_p);                  \
631       }                                                                        \
632    }                                                                           \
633 }
634 
635 /**
636  * This method simply adds a LIST_ELEMENT for the supplied object to the back
637  * (tail) of the supplied list.
638  */
639 #define sci_abstract_list_pushback(                                            \
640    list_p,                                                                     \
641    obj_p                                                                       \
642 )                                                                              \
643 {                                                                              \
644    SCI_ABSTRACT_ELEMENT_LIST_T * elem_list = &(list_p)->elements;              \
645    SCI_ABSTRACT_ELEMENT_T      * alElement_p                                   \
646       = private_pool_allocate((list_p)->free_pool);                            \
647    assert(alElement_p != NULL);                                                \
648                                                                                \
649    alElement_p->object_p = (obj_p);                                            \
650                                                                                \
651    if (elem_list->front_p == NULL)                                             \
652    {                                                                           \
653       elem_list->front_p = elem_list->back_p = alElement_p;                    \
654    }                                                                           \
655    else                                                                        \
656    {                                                                           \
657       elem_list->back_p->next_p = alElement_p;                                 \
658       alElement_p->previous_p   = elem_list->back_p;                           \
659       elem_list->back_p         = alElement_p;                                 \
660    }                                                                           \
661                                                                                \
662    elem_list->size++;                                                          \
663 }
664 
665 /**
666  * This method simply adds a LIST_ELEMENT for the supplied object to the front
667  * (head) of the supplied list.
668  */
669 #define sci_abstract_list_pushfront(                                           \
670    list_p,                                                                     \
671    obj_p                                                                       \
672 )                                                                              \
673 {                                                                              \
674    SCI_ABSTRACT_ELEMENT_T * alElement_p =                                      \
675          private_pool_allocate((list_p)->free_pool);                           \
676    alElement_p->object_p = (obj_p);                                            \
677    private_push_front(&(list_p)->elements, alElement_p);                       \
678 }
679 
680 /**
681  * This method will add the objToAdd_p object to the list before the obj_p.
682  * NOTE: UNIMPLEMENTED
683  */
684 #define sci_abstract_list_insert(                                              \
685    list_p,                                                                     \
686    obj_p,                                                                      \
687    objToAdd_p                                                                  \
688 )                                                                              \
689 {                                                                              \
690    SCI_ABSTRACT_ELEMENT_LIST_T * elem_list = &(list_p)->elements;              \
691                                                                                \
692    SCI_ABSTRACT_ELEMENT_T * obj_element = private_find(elem_list, obj_p);      \
693                                                                                \
694    SCI_ABSTRACT_ELEMENT_T * objToAdd_element =                                 \
695       private_pool_allocate((list_p)->free_pool);                              \
696                                                                                \
697    objToAdd_element->object_p = objToAdd_p;                                    \
698                                                                                \
699    ASSERT(obj_element != NULL);                                                \
700    ASSERT(objToAdd_element != NULL);                                           \
701                                                                                \
702    if (obj_element == elem_list->front_p)                                      \
703    {                                                                           \
704       objToAdd_element->object_p = (objToAdd_p);                               \
705       private_push_front(&(list_p)->elements, objToAdd_element);               \
706    }                                                                           \
707    else                                                                        \
708    {                                                                           \
709       obj_element->previous_p->next_p = objToAdd_element;                      \
710       objToAdd_element->previous_p = obj_element->previous_p;                  \
711                                                                                \
712       obj_element->previous_p = objToAdd_element;                              \
713       objToAdd_element->next_p = obj_element;                                  \
714                                                                                \
715       elem_list->size++;                                                       \
716    }                                                                           \
717 }
718 
719 /**
720  * This method simply frees all the items from the list.
721  */
722 #define sci_abstract_list_clear(                                               \
723    list_p                                                                      \
724 )                                                                              \
725 {                                                                              \
726    while ((list_p)->elements.size > 0)                                         \
727       sci_abstract_list_popfront((list_p));                                    \
728 }
729 
730 /**
731  * This method simply returns the object being pointed to by the list element
732  * (The item being listed).
733  */
734 #define sci_abstract_list_get_object(                                          \
735    alElement_p                                                                 \
736 )                                                                              \
737 ({                                                                             \
738    void * obj_p = NULL;                                                        \
739    if ((alElement_p) != NULL)                                                  \
740       obj_p = (alElement_p)->object_p;                                         \
741                                                                                \
742    obj_p;                                                                      \
743 })
744 
745 /**
746  * This method is simply a wrapper to provide the number of elements in
747  * the free list.
748  */
749 #define sci_abstract_list_freeList_size(freeList) (sci_abstract_list_size(freeList))
750 
751 //******************************************************************************
752 //*
753 //*     P R I V A T E   M E T H O D S
754 //*
755 //******************************************************************************
756 
757 /**
758  * This method simply performs the common portion of pushing a list element
759  * onto a list.
760  *
761  * WARNING: This is a private helper method that should not be called directly
762  *          by any users.
763  */
764 #define private_push_front(                                                    \
765    privateList_p,                                                              \
766    alElement_p                                                                 \
767 )                                                                              \
768 {                                                                              \
769    if ((privateList_p)->front_p == NULL)                                       \
770    {                                                                           \
771       (privateList_p)->front_p = (privateList_p)->back_p = (alElement_p);      \
772       (alElement_p)->next_p = (alElement_p)->previous_p = NULL;                \
773    }                                                                           \
774    else                                                                        \
775    {                                                                           \
776       (alElement_p)->next_p                = (privateList_p)->front_p;         \
777       (alElement_p)->previous_p            = NULL;                             \
778       (privateList_p)->front_p->previous_p = (alElement_p);                    \
779       (privateList_p)->front_p             = (alElement_p);                    \
780    }                                                                           \
781                                                                                \
782    (privateList_p)->size++;                                                    \
783 }
784 
785 /**
786  * This method simply performs the common portion of popping a list element
787  * from a list.
788  *
789  * WARNING: This is a private helper method that should not be called directly
790  *          by any users.
791  */
792 #define private_pop_front(                                                     \
793    privateList_p                                                               \
794 )                                                                              \
795 ({                                                                             \
796    SCI_ABSTRACT_ELEMENT_T * alElement_p = (privateList_p)->front_p;            \
797                                                                                \
798    if (alElement_p != NULL)                                                    \
799    {                                                                           \
800       if ((privateList_p)->front_p == (privateList_p)->back_p)                 \
801       {                                                                        \
802          (privateList_p)->front_p = (privateList_p)->back_p = NULL;            \
803       }                                                                        \
804       else                                                                     \
805       {                                                                        \
806          (privateList_p)->front_p = (privateList_p)->front_p->next_p;          \
807          (privateList_p)->front_p->previous_p = NULL;                          \
808       }                                                                        \
809                                                                                \
810       (privateList_p)->size--;                                                 \
811    }                                                                           \
812                                                                                \
813    alElement_p;                                                                \
814 })
815 
816 /**
817  * This method will simply search the supplied list for the desired object.
818  * It will return a pointer to the abstract_list_element if found, otherwise
819  * it will return NULL.
820  */
821 #define private_find(                                                          \
822    list_p,                                                                     \
823    obj_p                                                                       \
824 )                                                                              \
825 ({                                                                             \
826    SCI_ABSTRACT_ELEMENT_T * alElement_p = (list_p)->front_p;                   \
827                                                                                \
828    while (alElement_p != NULL)                                                 \
829    {                                                                           \
830       /* Check to see if we found the object for which we are searching. */    \
831       if (alElement_p->object_p == (void*) (obj_p))                            \
832       {                                                                        \
833          break;                                                                \
834       }                                                                        \
835                                                                                \
836       alElement_p = alElement_p->next_p;                                       \
837    }                                                                           \
838                                                                                \
839    alElement_p;                                                                \
840 })
841 
842 /**
843  * This private method will free the supplied list element back to the pool
844  * of free list elements.
845  */
846 #define private_pool_free(                                                     \
847    free_pool,                                                                  \
848    alElement_p                                                                 \
849 )                                                                              \
850 {                                                                              \
851    /* Push the list element back to the head to get better locality of */      \
852    /* reference with the cache.                                        */      \
853    private_push_front(&(free_pool)->free_list, (alElement_p));                 \
854 }
855 
856 /**
857  * This private method will allocate a list element from the pool of free
858  * list elements.
859  */
860 #define private_pool_allocate(free_pool)                                       \
861 ({                                                                             \
862    SCI_ABSTRACT_ELEMENT_T * alElement_p;                                       \
863                                                                                \
864    alElement_p = private_pop_front(&(free_pool)->free_list);                   \
865                                                                                \
866    memset(alElement_p, 0, sizeof(SCI_ABSTRACT_ELEMENT_T));                     \
867    alElement_p;                                                                \
868 })
869 
870 #endif
871 #endif // _ABSTRACT_LIST_H_
872