gnu/dist/texinfo/info/gc.c

   1 /*      $NetBSD$        */
   2
   3 /* gc.c -- Functions to remember and garbage collect unused node contents.
   4    Id: gc.c,v 1.3 2004/04/11 17:56:45 karl Exp
   5
   6    Copyright (C) 1993, 2004 Free Software Foundation, Inc.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    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 General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21
  22    Written by Brian Fox (bfox@ai.mit.edu). */
  23
  24 #include "info.h"
  25
  26 /* Array of pointers to the contents of gc-able nodes.  A pointer on this
  27    list can be garbage collected when no info window contains a node whose
  28    contents member match the pointer. */
  29 static char **gcable_pointers = (char **)NULL;
  30 static int gcable_pointers_index = 0;
  31 static int gcable_pointers_slots = 0;
  32
  33 /* Add POINTER to the list of garbage collectible pointers.  A pointer
  34    is not actually garbage collected until no info window contains a node
  35    whose contents member is equal to the pointer. */
  36 void
  37 add_gcable_pointer (char *pointer)
  38 {
  39   gc_pointers ();
  40   add_pointer_to_array (pointer, gcable_pointers_index, gcable_pointers,
  41                         gcable_pointers_slots, 10, char *);
  42 }
  43
  44 /* Grovel the list of info windows and gc-able pointers finding those
  45    node->contents which are collectible, and free them. */
  46 void
  47 gc_pointers (void)
  48 {
  49   register int i, j, k;
  50   INFO_WINDOW *iw;
  51   char **new = (char **)NULL;
  52   int new_index = 0;
  53   int new_slots = 0;
  54
  55   if (!info_windows || !gcable_pointers_index)
  56     return;
  57
  58   for (i = 0; (iw = info_windows[i]); i++)
  59     {
  60       for (j = 0; j < iw->nodes_index; j++)
  61         {
  62           NODE *node = iw->nodes[j];
  63
  64           /* If this node->contents appears in our list of gcable_pointers,
  65              it is not gc-able, so save it. */
  66           for (k = 0; k < gcable_pointers_index; k++)
  67             if (gcable_pointers[k] == node->contents)
  68               {
  69                 add_pointer_to_array
  70                   (node->contents, new_index, new, new_slots, 10, char *);
  71                 break;
  72               }
  73         }
  74     }
  75
  76   /* We have gathered all of the pointers which need to be saved.  Free any
  77      of the original pointers which do not appear in the new list. */
  78   for (i = 0; i < gcable_pointers_index; i++)
  79     {
  80       for (j = 0; j < new_index; j++)
  81         if (gcable_pointers[i] == new[j])
  82           break;
  83
  84       /* If we got all the way through the new list, then the old pointer
  85          can be garbage collected. */
  86       if (new && !new[j])
  87         free (gcable_pointers[i]);
  88     }
  89
  90   free (gcable_pointers);
  91   gcable_pointers = new;
  92   gcable_pointers_slots = new_slots;
  93   gcable_pointers_index = new_index;
  94 }