src/util-slist.c

   1 /*
   2     Copyright (C) 2012, 2013, 2014, 2015, 2016, 2017
   3     Ben Kibbey <bjk@luxsci.net>
   4
   5     This file is part of pwmd.
   6
   7     Pwmd is free software: you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation, either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     Pwmd is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with Pwmd.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <stdio.h>
  25 #include "util-slist.h"
  26 #include "mem.h"
  27
  28 unsigned
  29 slist_length (struct slist_s *list)
  30 {
  31   struct slist_s *cur;
  32   unsigned n = 0;
  33
  34   for (cur = list; cur; cur = cur->next)
  35     n++;
  36
  37   return n;
  38 }
  39
  40 void *
  41 slist_nth_data (struct slist_s *list, unsigned n)
  42 {
  43   struct slist_s *cur;
  44   unsigned i;
  45
  46   for (i = 0, cur = list; cur; cur = cur->next, i++)
  47     {
  48       if (i == n)
  49         return cur->data;
  50     }
  51
  52   return NULL;
  53 }
  54
  55 struct slist_s *
  56 slist_append (struct slist_s *list, void *data)
  57 {
  58   struct slist_s *cur;
  59
  60   if (!list)
  61     {
  62       cur = xcalloc (1, sizeof (struct slist_s));
  63       cur->data = data;
  64       return cur;
  65     }
  66
  67   for (cur = list; cur; cur = cur->next)
  68     {
  69       if (!cur->next)
  70         break;
  71     }
  72
  73   cur->next = xcalloc (1, sizeof (struct slist_s));
  74   cur->next->data = data;
  75   return list;
  76 }
  77
  78 static struct slist_s *
  79 free_once (struct slist_s *cur)
  80 {
  81   struct slist_s *next = cur ? cur->next : NULL;
  82
  83   xfree (cur);
  84   return next;
  85 }
  86
  87 void
  88 slist_free (struct slist_s *list)
  89 {
  90   while (list)
  91     list = free_once (list);
  92 }
  93
  94 struct slist_s *
  95 slist_remove (struct slist_s *list, void *data)
  96 {
  97   struct slist_s *prev, *cur;
  98
  99   for (cur = prev = list; cur; prev = cur, cur = cur->next)
 100     {
 101       if (cur->data == data)
 102         {
 103           struct slist_s *next = free_once (cur);
 104
 105           if (cur != list)
 106             prev->next = next;
 107           else
 108             list = next;
 109           break;
 110         }
 111     }
 112
 113   return list;
 114 }