trunk/src/list.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 2000-2018 ircd-hybrid development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file list.c
 * \brief Maintains doubly-linked lists.
 * \version $Id$
 */

#include "stdinc.h"
#include "list.h"
#include "mempool.h"


static mp_pool_t *dnode_pool;


/* init_dlink_nodes()
 *
 * inputs       - NONE
 * output       - NONE
 * side effects - initializes the dnode BlockHeap
 */
void
init_dlink_nodes(void)
{
  dnode_pool = mp_pool_new(sizeof(dlink_node), MP_CHUNK_SIZE_DNODE);
}

/* make_dlink_node()
 *
 * inputs       - NONE
 * output       - pointer to new dlink_node
 * side effects - NONE
 */
dlink_node *
make_dlink_node(void)
{
  dlink_node *node = mp_pool_get(dnode_pool);

  return node;
}

/* free_dlink_node()
 *
 * inputs       - pointer to dlink_node
 * output       - NONE
 * side effects - free given dlink_node
 */
void
free_dlink_node(dlink_node *node)
{
  mp_pool_release(node);
}

/*
 * dlink_ routines are stolen from squid, except for dlinkAddBefore,
 * which is mine.
 *   -- adrian
 */
void
dlinkAdd(void *data, dlink_node *m, dlink_list *list)
{
  m->data = data;
  m->prev = NULL;
  m->next = list->head;

  /* Assumption: If list->tail != NULL, list->head != NULL */
  if (list->head)
    list->head->prev = m;
  else if (list->tail == NULL)
    list->tail = m;

  list->head = m;
  list->length++;
}

void
dlinkAddBefore(dlink_node *b, void *data, dlink_node *m, dlink_list *list)
{
  /* Shortcut - if it's the first one, call dlinkAdd only */
  if (b == list->head)
    dlinkAdd(data, m, list);
  else
  {
    m->data = data;
    b->prev->next = m;
    m->prev = b->prev;
    b->prev = m;
    m->next = b;
    list->length++;
  }
}

void
dlinkAddTail(void *data, dlink_node *m, dlink_list *list)
{
  m->data = data;
  m->next = NULL;
  m->prev = list->tail;

  /* Assumption: If list->tail != NULL, list->head != NULL */
  if (list->tail)
    list->tail->next = m;
  else if (list->head == NULL)
    list->head = m;

  list->tail = m;
  list->length++;
}

/* Execution profiles show that this function is called the most
 * often of all non-spontaneous functions. So it had better be
 * efficient. */
void
dlinkDelete(dlink_node *m, dlink_list *list)
{
  assert(list->length > 0);

  /* Assumption: If m->next == NULL, then list->tail == m
   *      and:   If m->prev == NULL, then list->head == m
   */
  if (m->next)
    m->next->prev = m->prev;
  else
  {
    assert(list->tail == m);
    list->tail = m->prev;
  }

  if (m->prev)
    m->prev->next = m->next;
  else
  {
    assert(list->head == m);
    list->head = m->next;
  }

  /* Set this to NULL does matter */
  m->data = NULL;
  m->next = NULL;
  m->prev = NULL;

  list->length--;
}

/*
 * dlinkFind
 * inputs       - list to search
 *              - data
 * output       - pointer to link or NULL if not found
 * side effects - Look for ptr in the linked listed pointed to by link.
 */
dlink_node *
dlinkFind(dlink_list *list, const void *data)
{
  dlink_node *node;

  DLINK_FOREACH(node, list->head)
    if (node->data == data)
      return node;

  return NULL;
}

void
dlinkMoveList(dlink_list *from, dlink_list *to)
{
  /* There are three cases */
  /* case one, nothing in from list */
  if (from->head == NULL)
    return;

  /* case two, nothing in to list */
  /* actually if to->head is NULL and to->tail isn't, that's a bug */
  if (to->head == NULL)
  {
    to->head = from->head;
    to->tail = from->tail;
    from->head = from->tail = NULL;
    to->length = from->length;
    from->length = 0;
    return;
  }

  /* third case play with the links */
  from->tail->next = to->head;
  from->head->prev = to->head->prev;
  to->head->prev = from->tail;
  to->head = from->head;
  from->head = from->tail = NULL;
  to->length += from->length;
  from->length = 0;
  /* I think I got that right */
}

void
dlink_move_node(dlink_node *m, dlink_list *list_del, dlink_list *list_add)
{
  /* Assumption: If m->next == NULL, then list_del->tail == m
   *      and:   If m->prev == NULL, then list_del->head == m
   */
  if (m->next)
    m->next->prev = m->prev;
  else
  {
    assert(list_del->tail == m);
    list_del->tail = m->prev;
  }

  if (m->prev)
    m->prev->next = m->next;
  else
  {
    assert(list_del->head == m);
    list_del->head = m->next;
  }

  /* Set this to NULL does matter */
  m->prev = NULL;
  m->next = list_add->head;

  /* Assumption: If list_add->tail != NULL, list_add->head != NULL */
  if (list_add->head)
    list_add->head->prev = m;
  else if (list_add->tail == NULL)
    list_add->tail = m;

  list_add->head = m;
  list_add->length++;
  list_del->length--;
}

dlink_node *
dlinkFindDelete(dlink_list *list, void *data)
{
  dlink_node *m;

  DLINK_FOREACH(m, list->head)
  {
    if (m->data == data)
    {
      dlinkDelete(m, list);
      return m;
    }
  }

  return NULL;
}
Revision:	8296
Committed:	Sun Feb 25 10:20:19 2018 UTC (7 years, 6 months ago) by michael
Content type:	text/x-csrc
File size:	5609 byte(s)
Log Message:	- list.c:dlinkDelete(): added assert()
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 2000-2018 ircd-hybrid development team
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	* USA
20	*/
21
22	/*! \file list.c
23	* \brief Maintains doubly-linked lists.
24	* \version $Id$
25	*/
26
27	#include "stdinc.h"
28	#include "list.h"
29	#include "mempool.h"
30
31
32	static mp_pool_t *dnode_pool;
33
34
35	/* init_dlink_nodes()
36	*
37	* inputs - NONE
38	* output - NONE
39	* side effects - initializes the dnode BlockHeap
40	*/
41	void
42	init_dlink_nodes(void)
43	{
44	dnode_pool = mp_pool_new(sizeof(dlink_node), MP_CHUNK_SIZE_DNODE);
45	}
46
47	/* make_dlink_node()
48	*
49	* inputs - NONE
50	* output - pointer to new dlink_node
51	* side effects - NONE
52	*/
53	dlink_node *
54	make_dlink_node(void)
55	{
56	dlink_node *node = mp_pool_get(dnode_pool);
57
58	return node;
59	}
60
61	/* free_dlink_node()
62	*
63	* inputs - pointer to dlink_node
64	* output - NONE
65	* side effects - free given dlink_node
66	*/
67	void
68	free_dlink_node(dlink_node *node)
69	{
70	mp_pool_release(node);
71	}
72
73	/*
74	* dlink_ routines are stolen from squid, except for dlinkAddBefore,
75	* which is mine.
76	* -- adrian
77	*/
78	void
79	dlinkAdd(void data, dlink_node m, dlink_list *list)
80	{
81	m->data = data;
82	m->prev = NULL;
83	m->next = list->head;
84
85	/* Assumption: If list->tail != NULL, list->head != NULL */
86	if (list->head)
87	list->head->prev = m;
88	else if (list->tail == NULL)
89	list->tail = m;
90
91	list->head = m;
92	list->length++;
93	}
94
95	void
96	dlinkAddBefore(dlink_node b, void data, dlink_node m, dlink_list list)
97	{
98	/* Shortcut - if it's the first one, call dlinkAdd only */
99	if (b == list->head)
100	dlinkAdd(data, m, list);
101	else
102	{
103	m->data = data;
104	b->prev->next = m;
105	m->prev = b->prev;
106	b->prev = m;
107	m->next = b;
108	list->length++;
109	}
110	}
111
112	void
113	dlinkAddTail(void data, dlink_node m, dlink_list *list)
114	{
115	m->data = data;
116	m->next = NULL;
117	m->prev = list->tail;
118
119	/* Assumption: If list->tail != NULL, list->head != NULL */
120	if (list->tail)
121	list->tail->next = m;
122	else if (list->head == NULL)
123	list->head = m;
124
125	list->tail = m;
126	list->length++;
127	}
128
129	/* Execution profiles show that this function is called the most
130	* often of all non-spontaneous functions. So it had better be
131	* efficient. */
132	void
133	dlinkDelete(dlink_node m, dlink_list list)
134	{
135	assert(list->length > 0);
136
137	/* Assumption: If m->next == NULL, then list->tail == m
138	* and: If m->prev == NULL, then list->head == m
139	*/
140	if (m->next)
141	m->next->prev = m->prev;
142	else
143	{
144	assert(list->tail == m);
145	list->tail = m->prev;
146	}
147
148	if (m->prev)
149	m->prev->next = m->next;
150	else
151	{
152	assert(list->head == m);
153	list->head = m->next;
154	}
155
156	/* Set this to NULL does matter */
157	m->data = NULL;
158	m->next = NULL;
159	m->prev = NULL;
160
161	list->length--;
162	}
163
164	/*
165	* dlinkFind
166	* inputs - list to search
167	* - data
168	* output - pointer to link or NULL if not found
169	* side effects - Look for ptr in the linked listed pointed to by link.
170	*/
171	dlink_node *
172	dlinkFind(dlink_list list, const void data)
173	{
174	dlink_node *node;
175
176	DLINK_FOREACH(node, list->head)
177	if (node->data == data)
178	return node;
179
180	return NULL;
181	}
182
183	void
184	dlinkMoveList(dlink_list from, dlink_list to)
185	{
186	/* There are three cases */
187	/* case one, nothing in from list */
188	if (from->head == NULL)
189	return;
190
191	/* case two, nothing in to list */
192	/* actually if to->head is NULL and to->tail isn't, that's a bug */
193	if (to->head == NULL)
194	{
195	to->head = from->head;
196	to->tail = from->tail;
197	from->head = from->tail = NULL;
198	to->length = from->length;
199	from->length = 0;
200	return;
201	}
202
203	/* third case play with the links */
204	from->tail->next = to->head;
205	from->head->prev = to->head->prev;
206	to->head->prev = from->tail;
207	to->head = from->head;
208	from->head = from->tail = NULL;
209	to->length += from->length;
210	from->length = 0;
211	/* I think I got that right */
212	}
213
214	void
215	dlink_move_node(dlink_node m, dlink_list list_del, dlink_list *list_add)
216	{
217	/* Assumption: If m->next == NULL, then list_del->tail == m
218	* and: If m->prev == NULL, then list_del->head == m
219	*/
220	if (m->next)
221	m->next->prev = m->prev;
222	else
223	{
224	assert(list_del->tail == m);
225	list_del->tail = m->prev;
226	}
227
228	if (m->prev)
229	m->prev->next = m->next;
230	else
231	{
232	assert(list_del->head == m);
233	list_del->head = m->next;
234	}
235
236	/* Set this to NULL does matter */
237	m->prev = NULL;
238	m->next = list_add->head;
239
240	/* Assumption: If list_add->tail != NULL, list_add->head != NULL */
241	if (list_add->head)
242	list_add->head->prev = m;
243	else if (list_add->tail == NULL)
244	list_add->tail = m;
245
246	list_add->head = m;
247	list_add->length++;
248	list_del->length--;
249	}
250
251	dlink_node *
252	dlinkFindDelete(dlink_list list, void data)
253	{
254	dlink_node *m;
255
256	DLINK_FOREACH(m, list->head)
257	{
258	if (m->data == data)
259	{
260	dlinkDelete(m, list);
261	return m;
262	}
263	}
264
265	return NULL;
266	}