src/extras/tdestroy.c

   1 /**
   2  * @file tdestroy.c
   3  * @brief replacement for GNU tdestroy()
   4  */
   5 /*****************************************************************************
   6  * Copyright (C) 2009 Rémi Denis-Courmont
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include "config.h"
  25 #endif
  26
  27 #if defined(HAVE_SEARCH_H) && !defined(HAVE_TDESTROY) && defined(HAVE_TFIND)
  28
  29 #include <stdlib.h>
  30 #include <assert.h>
  31
  32 #include <vlc_common.h>
  33 #include <search.h>
  34
  35 static struct
  36 {
  37     const void **tab;
  38     size_t count;
  39     vlc_mutex_t lock;
  40 } list = { NULL, 0, VLC_STATIC_MUTEX };
  41
  42 static void list_nodes (const void *node, const VISIT which, const int depth)
  43 {
  44     (void) depth;
  45
  46     if (which != postorder && which != leaf)
  47         return;
  48
  49     const void **tab = realloc (list.tab, sizeof (*tab) * (list.count + 1));
  50     if (unlikely(tab == NULL))
  51         abort ();
  52
  53     tab[list.count] = *(const void **)node;
  54     list.tab = tab;
  55     list.count++;
  56 }
  57
  58 static struct
  59 {
  60     const void *node;
  61     vlc_mutex_t lock;
  62 } smallest = { NULL, VLC_STATIC_MUTEX };
  63
  64 static int cmp_smallest (const void *a, const void *b)
  65 {
  66     if (a == b)
  67         return 0;
  68     if (a == smallest.node)
  69         return -1;
  70     if (likely(b == smallest.node))
  71         return +1;
  72     abort ();
  73 }
  74
  75 void vlc_tdestroy (void *root, void (*freenode) (void *))
  76 {
  77     const void **tab;
  78     size_t count;
  79
  80     assert (freenode != NULL);
  81
  82     /* Enumerate nodes in order */
  83     vlc_mutex_lock (&list.lock);
  84     assert (list.count == 0);
  85     twalk (root, list_nodes);
  86     tab = list.tab;
  87     count = list.count;
  88     list.tab = NULL;
  89     list.count = 0;
  90     vlc_mutex_unlock (&list.lock);
  91
  92     /* Destroy the tree */
  93     vlc_mutex_lock (&smallest.lock);
  94     for (size_t i = 0; i < count; i++)
  95     {
  96          void *node  = tab[i];
  97
  98          smallest.node = node;
  99          node = tdelete (node, &root, cmp_smallest);
 100          assert (node != NULL);
 101     }
 102     vlc_mutex_unlock (&smallest.lock);
 103     assert (root == NULL);
 104
 105     /* Destroy the nodes */
 106     for (size_t i = 0; i < count; i++)
 107          freenode ((void *)(tab[i]));
 108     free (tab);
 109 }
 110
 111 #endif