从DNS服务器应用极广的BIND9.9.2 中提取的双向链表，可以用于自己的程序，也可以用来理解BIND

/*
* Copyright (C) 2004, 2006, 2007, 2011, 2012  Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 1997-2002  Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/

/* $Id$ */

#ifndef ISC_LIST_H
#define ISC_LIST_H 1
#include "boolean.h"

#ifdef ISC_LIST_CHECKINIT
#define ISC_LINK_INSIST(x) ISC_INSIST(x)
#else
#define ISC_LINK_INSIST(x)
#define ISC_INSIST
#endif

#define ISC_LIST(type) struct { type *head, *tail; }
#define ISC_LIST_INIT(list) \
do { (list).head = NULL; (list).tail = NULL; } while (0)

#define ISC_LINK(type) struct { type *prev, *next; }
#define ISC_LINK_INIT_TYPE(elt, link, type) \
do { \
(elt)->link.prev = (type *)(-1); \
(elt)->link.next = (type *)(-1); \
} while (0)
#define ISC_LINK_INIT(elt, link) \
ISC_LINK_INIT_TYPE(elt, link, void)
#define ISC_LINK_LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1))

#define ISC_LIST_HEAD(list) ((list).head)
#define ISC_LIST_TAIL(list) ((list).tail)
#define ISC_LIST_EMPTY(list) ISC_TF((list).head == NULL)

#define __ISC_LIST_PREPENDUNSAFE(list, elt, link) \
do { \
if ((list).head != NULL) \
(list).head->link.prev = (elt); \
else \
(list).tail = (elt); \
(elt)->link.prev = NULL; \
(elt)->link.next = (list).head; \
(list).head = (elt); \
} while (0)

#define ISC_LIST_PREPEND(list, elt, link) \
do { \
ISC_LINK_INSIST(!ISC_LINK_LINKED(elt, link)); \
__ISC_LIST_PREPENDUNSAFE(list, elt, link); \
} while (0)

#define ISC_LIST_INITANDPREPEND(list, elt, link) \
__ISC_LIST_PREPENDUNSAFE(list, elt, link)

#define __ISC_LIST_APPENDUNSAFE(list, elt, link) \
do { \
if ((list).tail != NULL) \
(list).tail->link.next = (elt); \
else \
(list).head = (elt); \
(elt)->link.prev = (list).tail; \
(elt)->link.next = NULL; \
(list).tail = (elt); \
} while (0)

#define ISC_LIST_APPEND(list, elt, link) \
do { \
ISC_LINK_INSIST(!ISC_LINK_LINKED(elt, link)); \
__ISC_LIST_APPENDUNSAFE(list, elt, link); \
} while (0)

#define ISC_LIST_INITANDAPPEND(list, elt, link) \
__ISC_LIST_APPENDUNSAFE(list, elt, link)

#define __ISC_LIST_UNLINKUNSAFE_TYPE(list, elt, link, type) \
do { \
if ((elt)->link.next != NULL) \
(elt)->link.next->link.prev = (elt)->link.prev; \
else { \
ISC_INSIST((list).tail == (elt)); \
(list).tail = (elt)->link.prev; \
} \
if ((elt)->link.prev != NULL) \
(elt)->link.prev->link.next = (elt)->link.next; \
else { \
ISC_INSIST((list).head == (elt)); \
(list).head = (elt)->link.next; \
} \
(elt)->link.prev = (type *)(-1); \
(elt)->link.next = (type *)(-1); \
} while (0)

#define __ISC_LIST_UNLINKUNSAFE(list, elt, link) \
__ISC_LIST_UNLINKUNSAFE_TYPE(list, elt, link, void)

#define ISC_LIST_UNLINK_TYPE(list, elt, link, type) \
do { \
ISC_LINK_INSIST(ISC_LINK_LINKED(elt, link)); \
__ISC_LIST_UNLINKUNSAFE_TYPE(list, elt, link, type); \
} while (0)
#define ISC_LIST_UNLINK(list, elt, link) \
ISC_LIST_UNLINK_TYPE(list, elt, link, void)

#define ISC_LIST_PREV(elt, link) ((elt)->link.prev)
#define ISC_LIST_NEXT(elt, link) ((elt)->link.next)

#define __ISC_LIST_INSERTBEFOREUNSAFE(list, before, elt, link) \
do { \
if ((before)->link.prev == NULL) \
ISC_LIST_PREPEND(list, elt, link); \
else { \
(elt)->link.prev = (before)->link.prev; \
(before)->link.prev = (elt); \
(elt)->link.prev->link.next = (elt); \
(elt)->link.next = (before); \
} \
} while (0)

#define ISC_LIST_INSERTBEFORE(list, before, elt, link) \
do { \
ISC_LINK_INSIST(ISC_LINK_LINKED(before, link)); \
ISC_LINK_INSIST(!ISC_LINK_LINKED(elt, link)); \
__ISC_LIST_INSERTBEFOREUNSAFE(list, before, elt, link); \
} while (0)

#define __ISC_LIST_INSERTAFTERUNSAFE(list, after, elt, link) \
do { \
if ((after)->link.next == NULL) \
ISC_LIST_APPEND(list, elt, link); \
else { \
(elt)->link.next = (after)->link.next; \
(after)->link.next = (elt); \
(elt)->link.next->link.prev = (elt); \
(elt)->link.prev = (after); \
} \
} while (0)

#define ISC_LIST_INSERTAFTER(list, after, elt, link) \
do { \
ISC_LINK_INSIST(ISC_LINK_LINKED(after, link)); \
ISC_LINK_INSIST(!ISC_LINK_LINKED(elt, link)); \
__ISC_LIST_INSERTAFTERUNSAFE(list, after, elt, link); \
} while (0)

#define ISC_LIST_APPENDLIST(list1, list2, link) \
do { \
if (ISC_LIST_EMPTY(list1)) \
(list1) = (list2); \
else if (!ISC_LIST_EMPTY(list2)) { \
(list1).tail->link.next = (list2).head; \
(list2).head->link.prev = (list1).tail; \
(list1).tail = (list2).tail; \
} \
(list2).head = NULL; \
(list2).tail = NULL; \
} while (0)

#define ISC_LIST_PREPENDLIST(list1, list2, link) \
do { \
if (ISC_LIST_EMPTY(list1)) \
(list1) = (list2); \
else if (!ISC_LIST_EMPTY(list2)) { \
(list2).tail->link.next = (list1).head; \
(list1).head->link.prev = (list2).tail; \
(list1).head = (list2).head; \
} \
(list2).head = NULL; \
(list2).tail = NULL; \
} while (0)

#define ISC_LIST_ENQUEUE(list, elt, link) ISC_LIST_APPEND(list, elt, link)
#define __ISC_LIST_ENQUEUEUNSAFE(list, elt, link) \
__ISC_LIST_APPENDUNSAFE(list, elt, link)
#define ISC_LIST_DEQUEUE(list, elt, link) \
ISC_LIST_UNLINK_TYPE(list, elt, link, void)
#define ISC_LIST_DEQUEUE_TYPE(list, elt, link, type) \
ISC_LIST_UNLINK_TYPE(list, elt, link, type)
#define __ISC_LIST_DEQUEUEUNSAFE(list, elt, link) \
__ISC_LIST_UNLINKUNSAFE_TYPE(list, elt, link, void)
#define __ISC_LIST_DEQUEUEUNSAFE_TYPE(list, elt, link, type) \
__ISC_LIST_UNLINKUNSAFE_TYPE(list, elt, link, type)

#endif /* ISC_LIST_H */

/*
* Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 1998-2001  Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/

/* $Id: boolean.h,v 1.19 2007/06/19 23:47:18 tbox Exp $ */

#ifndef ISC_BOOLEAN_H
#define ISC_BOOLEAN_H 1

/*! \file isc/boolean.h */

typedef enum { isc_boolean_false = 0, isc_boolean_true = 1 } isc_boolean_t;

#define ISC_FALSE isc_boolean_false
#define ISC_TRUE isc_boolean_true
#define ISC_TF(x) ((x) ? ISC_TRUE : ISC_FALSE)

#endif /* ISC_BOOLEAN_H */

#include <stdio.h>
#include <stdlib.h>
#include "list.h"

#define LIST(type)			ISC_LIST(type)
#define INIT_LIST(type)			ISC_LIST_INIT(type)
#define LINK(type)			ISC_LINK(type)
#define INIT_LINK(elt, link)		ISC_LINK_INIT(elt, link)
#define HEAD(list)			ISC_LIST_HEAD(list)
#define TAIL(list)			ISC_LIST_TAIL(list)
#define EMPTY(list)			ISC_LIST_EMPTY(list)
#define PREV(elt, link)			ISC_LIST_PREV(elt, link)
#define NEXT(elt, link)			ISC_LIST_NEXT(elt, link)
#define APPEND(list, elt, link)		ISC_LIST_APPEND(list, elt, link)
#define PREPEND(list, elt, link)	ISC_LIST_PREPEND(list, elt, link)
#define UNLINK(list, elt, link)		ISC_LIST_UNLINK(list, elt, link)
#define ENQUEUE(list, elt, link)	ISC_LIST_APPEND(list, elt, link)
#define DEQUEUE(list, elt, link)	ISC_LIST_UNLINK(list, elt, link)
#define INSERTBEFORE(li, b, e, ln)	ISC_LIST_INSERTBEFORE(li, b, e, ln)
#define INSERTAFTER(li, a, e, ln)	ISC_LIST_INSERTAFTER(li, a, e, ln)
#define APPENDLIST(list1, list2, link)	ISC_LIST_APPENDLIST(list1, list2, link)

//有两个测试，均验证通过
#if 0
typedef struct dns_dbimplementation		dns_dbimplementation_t;

struct dns_dbimplementation {
ISC_LINK(dns_dbimplementation_t)	link;
const char *				name;
};

static LIST(dns_dbimplementation_t) implementations;

void dump()
{
dns_dbimplementation_t *imp;

for (imp = ISC_LIST_HEAD(implementations);	imp != NULL; imp = ISC_LIST_NEXT(imp, link))
{
printf("%s\n",imp->name);
}

}

void main()
{

ISC_LIST_INIT(implementations);

dns_dbimplementation_t rbtimp;
rbtimp.name = "rbt1";
ISC_LINK_INIT(&rbtimp, link);
ISC_LIST_APPEND(implementations.link, &rbtimp, link);

dns_dbimplementation_t rbtimp2;
rbtimp2.name = "rbt2";
ISC_LINK_INIT(&rbtimp2, link);
ISC_LIST_APPEND(implementations, &rbtimp2, link);

dump();

ISC_LIST_UNLINK(implementations, &rbtimp2, link);

dump();
}
#else

struct isc__task {
char				name[16];
LINK(isc__task_t)		ready_link;
};

typedef struct isc__task isc__task_t;

typedef ISC_LIST(isc__task_t)	isc__tasklist_t;
typedef struct isc__taskmgr isc__taskmgr_t;
struct isc__taskmgr {
unsigned int			workers;
isc__tasklist_t		ready_tasks;
};

/*
list可以理解为链表节点的列表，它的元素是链表节点，
LINK可以理解为链表的一个节点
*/
void main()
{
isc__taskmgr_t *manager;
isc__task_t *task;
isc__tasklist_t new_ready_tasks;//list
ISC_LIST_INIT(new_ready_tasks);//list
ENQUEUE(new_ready_tasks, task, ready_link);//
ISC_LIST_APPENDLIST(manager->ready_tasks, new_ready_tasks, ready_link);
}
#endif