trunk/src/list.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 2000-2020 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 "memory.h"


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

  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)
{
  xfree(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->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:	9101
Committed:	Wed Jan 1 09:58:45 2020 UTC (5 years, 7 months ago) by michael
Content type:	text/x-csrc
File size:	5320 byte(s)
Log Message:	- Bump copyright years everywhere
#	User	Rev	Content
1	adx	30	/*
2	michael	2916	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	adx	30	*
4	michael	9101	* Copyright (c) 2000-2020 ircd-hybrid development team
5	adx	30	*
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	michael	4565	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	adx	30	* USA
20			*/
21
22	michael	2916	/*! \file list.c
23			* \brief Maintains doubly-linked lists.
24			* \version $Id$
25			*/
26
27	adx	30	#include "stdinc.h"
28			#include "list.h"
29	michael	8385	#include "memory.h"
30	adx	30
31	michael	2916
32	adx	30	/* make_dlink_node()
33			*
34			* inputs - NONE
35			* output - pointer to new dlink_node
36			* side effects - NONE
37			*/
38			dlink_node *
39			make_dlink_node(void)
40			{
41	michael	8385	dlink_node node = xcalloc(sizeof(node));
42	adx	30
43	michael	4815	return node;
44	adx	30	}
45
46			/* free_dlink_node()
47			*
48			* inputs - pointer to dlink_node
49			* output - NONE
50	michael	2916	* side effects - free given dlink_node
51	adx	30	*/
52			void
53	michael	4815	free_dlink_node(dlink_node *node)
54	adx	30	{
55	michael	8385	xfree(node);
56	adx	30	}
57	michael	1011
58			/*
59			* dlink_ routines are stolen from squid, except for dlinkAddBefore,
60			* which is mine.
61			* -- adrian
62			*/
63			void
64			dlinkAdd(void data, dlink_node m, dlink_list *list)
65			{
66			m->data = data;
67			m->prev = NULL;
68			m->next = list->head;
69
70			/* Assumption: If list->tail != NULL, list->head != NULL */
71	michael	3335	if (list->head)
72	michael	1011	list->head->prev = m;
73			else if (list->tail == NULL)
74			list->tail = m;
75
76			list->head = m;
77			list->length++;
78			}
79
80			void
81			dlinkAddBefore(dlink_node b, void data, dlink_node m, dlink_list list)
82			{
83	michael	7634	/* Shortcut - if it's the first one, call dlinkAdd only */
84	michael	1011	if (b == list->head)
85			dlinkAdd(data, m, list);
86			else
87			{
88			m->data = data;
89			b->prev->next = m;
90			m->prev = b->prev;
91			b->prev = m;
92			m->next = b;
93			list->length++;
94			}
95			}
96
97			void
98			dlinkAddTail(void data, dlink_node m, dlink_list *list)
99			{
100			m->data = data;
101			m->next = NULL;
102			m->prev = list->tail;
103
104			/* Assumption: If list->tail != NULL, list->head != NULL */
105	michael	3335	if (list->tail)
106	michael	1011	list->tail->next = m;
107			else if (list->head == NULL)
108			list->head = m;
109
110			list->tail = m;
111			list->length++;
112			}
113
114			/* Execution profiles show that this function is called the most
115			* often of all non-spontaneous functions. So it had better be
116			* efficient. */
117			void
118			dlinkDelete(dlink_node m, dlink_list list)
119			{
120	michael	8296	assert(list->length > 0);
121
122	michael	1011	/* Assumption: If m->next == NULL, then list->tail == m
123			* and: If m->prev == NULL, then list->head == m
124			*/
125			if (m->next)
126			m->next->prev = m->prev;
127			else
128			{
129			assert(list->tail == m);
130			list->tail = m->prev;
131			}
132
133			if (m->prev)
134			m->prev->next = m->next;
135			else
136			{
137			assert(list->head == m);
138			list->head = m->next;
139			}
140
141			/* Set this to NULL does matter */
142	michael	8290	m->next = NULL;
143			m->prev = NULL;
144
145	michael	1011	list->length--;
146			}
147
148			/*
149			* dlinkFind
150			* inputs - list to search
151			* - data
152			* output - pointer to link or NULL if not found
153			* side effects - Look for ptr in the linked listed pointed to by link.
154			*/
155			dlink_node *
156	michael	4785	dlinkFind(dlink_list list, const void data)
157	michael	1011	{
158	michael	8059	dlink_node *node;
159	michael	1011
160	michael	4815	DLINK_FOREACH(node, list->head)
161			if (node->data == data)
162			return node;
163	michael	1011
164			return NULL;
165			}
166
167			void
168			dlinkMoveList(dlink_list from, dlink_list to)
169			{
170			/* There are three cases */
171			/* case one, nothing in from list */
172			if (from->head == NULL)
173			return;
174
175			/* case two, nothing in to list */
176	michael	7634	/* actually if to->head is NULL and to->tail isn't, that's a bug */
177	michael	1011	if (to->head == NULL)
178			{
179			to->head = from->head;
180			to->tail = from->tail;
181			from->head = from->tail = NULL;
182			to->length = from->length;
183			from->length = 0;
184			return;
185			}
186
187			/* third case play with the links */
188			from->tail->next = to->head;
189			from->head->prev = to->head->prev;
190			to->head->prev = from->tail;
191			to->head = from->head;
192			from->head = from->tail = NULL;
193			to->length += from->length;
194			from->length = 0;
195			/* I think I got that right */
196			}
197
198	michael	1126	void
199			dlink_move_node(dlink_node m, dlink_list list_del, dlink_list *list_add)
200			{
201			/* Assumption: If m->next == NULL, then list_del->tail == m
202			* and: If m->prev == NULL, then list_del->head == m
203			*/
204			if (m->next)
205			m->next->prev = m->prev;
206			else
207			{
208	michael	1654	assert(list_del->tail == m);
209	michael	1126	list_del->tail = m->prev;
210			}
211
212			if (m->prev)
213			m->prev->next = m->next;
214			else
215			{
216	michael	1654	assert(list_del->head == m);
217	michael	1126	list_del->head = m->next;
218			}
219
220			/* Set this to NULL does matter */
221			m->prev = NULL;
222			m->next = list_add->head;
223
224			/* Assumption: If list_add->tail != NULL, list_add->head != NULL */
225	michael	5003	if (list_add->head)
226	michael	1126	list_add->head->prev = m;
227			else if (list_add->tail == NULL)
228			list_add->tail = m;
229
230			list_add->head = m;
231			list_add->length++;
232			list_del->length--;
233			}
234
235	michael	1011	dlink_node *
236			dlinkFindDelete(dlink_list list, void data)
237			{
238	michael	8059	dlink_node *m;
239	michael	1011
240			DLINK_FOREACH(m, list->head)
241			{
242	michael	7391	if (m->data == data)
243	michael	1011	{
244	michael	7391	dlinkDelete(m, list);
245			return m;
246	michael	2714	}
247	michael	1011	}
248
249			return NULL;
250			}