src/util-slist.c

   1 /*
   2     Copyright (C) 2012-2021 Ben Kibbey <bjk@luxsci.net>
   3
   4     This file is part of pwmd.
   5
   6     Pwmd is free software: you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License version 2 as
   8     published by the Free Software Foundation.
   9
  10     Pwmd is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with Pwmd.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #ifdef HAVE_CONFIG_H
  19 #include <config.h>
  20 #endif
  21
  22 #include <stdio.h>
  23 #include "util-slist.h"
  24 #include "mem.h"
  25
  26 unsigned
  27 slist_length (struct slist_s *list)
  28 {
  29   struct slist_s *cur;
  30   unsigned n = 0;
  31
  32   for (cur = list; cur; cur = cur->next)
  33     n++;
  34
  35   return n;
  36 }
  37
  38 void *
  39 slist_nth_data (struct slist_s *list, unsigned n)
  40 {
  41   struct slist_s *cur;
  42   unsigned i;
  43
  44   for (i = 0, cur = list; cur; cur = cur->next, i++)
  45     {
  46       if (i == n)
  47         return cur->data;
  48     }
  49
  50   return NULL;
  51 }
  52
  53 struct slist_s *
  54 slist_append (struct slist_s *list, void *data)
  55 {
  56   struct slist_s *cur;
  57
  58   if (!list)
  59     {
  60       cur = xcalloc (1, sizeof (struct slist_s));
  61       cur->data = data;
  62       return cur;
  63     }
  64
  65   for (cur = list; cur; cur = cur->next)
  66     {
  67       if (!cur->next)
  68         break;
  69     }
  70
  71   cur->next = xcalloc (1, sizeof (struct slist_s));
  72   cur->next->data = data;
  73   return list;
  74 }
  75
  76 static struct slist_s *
  77 free_once (struct slist_s *cur)
  78 {
  79   struct slist_s *next = cur ? cur->next : NULL;
  80
  81   xfree (cur);
  82   return next;
  83 }
  84
  85 void
  86 slist_free (struct slist_s *list)
  87 {
  88   while (list)
  89     list = free_once (list);
  90 }
  91
  92 struct slist_s *
  93 slist_remove (struct slist_s *list, void *data)
  94 {
  95   struct slist_s *prev, *cur;
  96
  97   for (cur = prev = list; cur; prev = cur, cur = cur->next)
  98     {
  99       if (cur->data == data)
 100         {
 101           struct slist_s *next = free_once (cur);
 102
 103           if (cur != list)
 104             prev->next = next;
 105           else
 106             list = next;
 107           break;
 108         }
 109     }
 110
 111   return list;
 112 }