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
   9  * it 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 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
  20  * Foundation, 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 #include <stdlib.h>
  28 #include <assert.h>
  29
  30 #include <vlc_common.h>
  31
  32 #ifdef HAVE_TDESTROY
  33 void vlc_tdestroy (void *root, void (*freenode) (void *))
  34 {
  35     (void) root;
  36     assert (freenode != NULL);
  37     abort ();
  38 }
  39
  40 #else
  41 #include <search.h>
  42
  43 static struct
  44 {
  45     const void **tab;
  46     size_t count;
  47     vlc_mutex_t lock;
  48 } list = { NULL, 0, VLC_STATIC_MUTEX };
  49
  50 static void list_nodes (const void *node, const VISIT which, const int depth)
  51 {
  52     (void) depth;
  53
  54     if (which != postorder && which != leaf)
  55         return;
  56
  57     const void **tab = realloc (list.tab, sizeof (*tab) * (list.count + 1));
  58     if (unlikely(tab == NULL))
  59         abort ();
  60
  61     tab[list.count] = *(const void **)node;
  62     list.tab = tab;
  63     list.count++;
  64 }
  65
  66 static struct
  67 {
  68     const void *node;
  69     vlc_mutex_t lock;
  70 } smallest = { NULL, VLC_STATIC_MUTEX };
  71
  72 static int cmp_smallest (const void *a, const void *b)
  73 {
  74     if (a == b)
  75         return 0;
  76     if (a == smallest.node)
  77         return -1;
  78     if (likely(b == smallest.node))
  79         return +1;
  80     abort ();
  81 }
  82
  83 void vlc_tdestroy (void *root, void (*freenode) (void *))
  84 {
  85     const void **tab;
  86     size_t count;
  87
  88     assert (freenode != NULL);
  89
  90     /* Enumerate nodes in order */
  91     vlc_mutex_lock (&list.lock);
  92     assert (list.count == 0);
  93     twalk (root, list_nodes);
  94     tab = list.tab;
  95     count = list.count;
  96     list.tab = NULL;
  97     list.count = 0;
  98     vlc_mutex_unlock (&list.lock);
  99
 100     /* Destroy the tree */
 101     vlc_mutex_lock (&smallest.lock);
 102     for (size_t i = 0; i < count; i++)
 103     {
 104          smallest.node = tab[i];
 105          if (tdelete (smallest.node, &root, cmp_smallest) == NULL)
 106              abort ();
 107     }
 108     vlc_mutex_unlock (&smallest.lock);
 109     assert (root == NULL);
 110
 111     /* Destroy the nodes */
 112     for (size_t i = 0; i < count; i++)
 113          freenode ((void *)(tab[i]));
 114     free (tab);
 115 }
 116
 117 #endif