util/list.c

   1 /*
   2  * Copyright (c) 1995, 1996, 1997, 1998, 2002 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * List handling functions
  36  */
  37
  38 #ifdef HAVE_CONFIG_H
  39 #include <config.h>
  40 RCSID("$Id$");
  41 #endif
  42
  43 #include <assert.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include "list.h"
  47
  48 /*
  49  * The representation is with a double-linked list, a pointer to
  50  * the tail, and another one to the head.
  51  */
  52
  53 /*
  54  * Create a new list.
  55  */
  56
  57 List*
  58 listnew (void)
  59 {
  60      List *tmp = (List *)malloc (sizeof (List));
  61
  62      if (tmp)
  63           tmp->head = tmp->tail = NULL;
  64      return tmp;
  65 }
  66
  67 /*
  68  * Free a list, assume that its empty
  69  */
  70
  71 void
  72 listfree(List *list)
  73 {
  74         list->head = list->tail = NULL;
  75         free(list);
  76 }
  77
  78 /*
  79  * Add an element before `item'
  80  */
  81
  82 Listitem *
  83 listaddbefore (List *list, Listitem *old_item, void *data)
  84 {
  85      Listitem *item = (Listitem *)malloc (sizeof (Listitem));
  86
  87      if (item == NULL)
  88          return item;
  89
  90      item->data = data;
  91      item->prev = old_item->prev;
  92      item->next = old_item;
  93      if (item->prev)
  94          item->prev->next = item;
  95      else
  96          list->head = item;
  97      old_item->prev = item;
  98      return item;
  99 }
 100
 101 /*
 102  * Add an element after `item'
 103  */
 104
 105 Listitem *
 106 listaddafter (List *list, Listitem *old_item, void *data)
 107 {
 108      Listitem *item = (Listitem *)malloc (sizeof (Listitem));
 109
 110      if (item == NULL)
 111          return item;
 112
 113      item->data = data;
 114      item->next = old_item->next;
 115      item->prev = old_item;
 116      if (item->next)
 117          item->next->prev = item;
 118      else
 119          list->tail = item;
 120      old_item->next = item;
 121      return item;
 122 }
 123
 124 /*
 125  * Add an element to the head of the list
 126  */
 127
 128 Listitem *
 129 listaddhead (List *list, void *data)
 130 {
 131      Listitem *item = (Listitem *)malloc (sizeof (Listitem));
 132
 133      if (item == NULL)
 134          return item;
 135
 136      item->data = data;
 137      item->prev = NULL;
 138      item->next = list->head;
 139      if (list->head)
 140           list->head->prev = item;
 141      list->head = item;
 142      if (list->tail == NULL)
 143           list->tail = item;
 144      return item;
 145 }
 146
 147 /*
 148  * Add an element to the tail of the list
 149  */
 150
 151 Listitem *
 152 listaddtail (List *list, void *data)
 153 {
 154      Listitem *item = (Listitem *)malloc (sizeof (Listitem));
 155
 156      if (item == NULL)
 157          return item;
 158
 159      item->data = data;
 160      item->next = NULL;
 161      item->prev = list->tail;
 162      if (list->tail)
 163           list->tail->next = item;
 164      list->tail = item;
 165      if (list->head == NULL)
 166           list->head = item;
 167      return item;
 168 }
 169
 170 /*
 171  * Remove an element from the head of the list.
 172  * Return this element.
 173  */
 174
 175 void *
 176 listdelhead (List *list)
 177 {
 178      Listitem   *item = list->head;
 179      void       *ret;
 180
 181      if (item == NULL)
 182          return NULL;
 183      ret = item->data;
 184
 185      list->head = list->head->next;
 186      if (list->head)
 187           list->head->prev = NULL;
 188      free(item);
 189      if (list->tail == item)
 190           list->tail = NULL;
 191      return ret;
 192 }
 193
 194 /*
 195  * Remove an element from the tail of the list.
 196  * Return this element.
 197  */
 198
 199 void *
 200 listdeltail (List *list)
 201 {
 202      Listitem   *item = list->tail;
 203      void       *ret;
 204
 205      if (item == NULL)
 206          return NULL;
 207      ret = item->data;
 208
 209      list->tail = list->tail->prev;
 210      if (list->tail)
 211           list->tail->next = NULL;
 212      free (item);
 213      if (list->head == item)
 214           list->head = NULL;
 215      return ret;
 216 }
 217
 218 /*
 219  * listdel
 220  */
 221
 222 void
 223 listdel (List *list, Listitem *item)
 224 {
 225      if (item->prev)
 226           item->prev->next = item->next;
 227      if (item->next)
 228           item->next->prev = item->prev;
 229      if (item == list->head)
 230           list->head = item->next;
 231      if (item == list->tail)
 232           list->tail = item->prev;
 233      free (item);
 234 }
 235
 236 /*
 237  * Iterate through all the items in a list.
 238  */
 239
 240 void listiter (List *list, Bool (*fn)(List *, Listitem *, void *arg),
 241                void *arg)
 242 {
 243      Listitem *item;
 244
 245      for (item = list->head; item; item = item->next)
 246           if ((*fn) (list, item, arg))
 247                break;
 248 }