| 1 | /* gc.c -- Functions to remember and garbage collect unused node contents.
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| 2 | $Id: gc.c,v 1.3 2004/04/11 17:56:45 karl Exp $
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| 3 |
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| 4 | Copyright (C) 1993, 2004 Free Software Foundation, Inc.
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| 5 |
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| 6 | This program is free software; you can redistribute it and/or modify
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| 7 | it under the terms of the GNU General Public License as published by
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| 8 | the Free Software Foundation; either version 2, or (at your option)
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| 9 | any later version.
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| 10 |
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| 11 | This program is distributed in the hope that it will be useful,
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | GNU General Public License for more details.
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| 15 |
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| 16 | You should have received a copy of the GNU General Public License
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| 17 | along with this program; if not, write to the Free Software
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| 18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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| 19 |
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| 20 | Written by Brian Fox (bfox@ai.mit.edu). */
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| 21 |
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| 22 | #include "info.h"
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| 23 |
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| 24 | /* Array of pointers to the contents of gc-able nodes. A pointer on this
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| 25 | list can be garbage collected when no info window contains a node whose
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| 26 | contents member match the pointer. */
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| 27 | static char **gcable_pointers = (char **)NULL;
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| 28 | static int gcable_pointers_index = 0;
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| 29 | static int gcable_pointers_slots = 0;
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| 30 |
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| 31 | /* Add POINTER to the list of garbage collectible pointers. A pointer
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| 32 | is not actually garbage collected until no info window contains a node
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| 33 | whose contents member is equal to the pointer. */
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| 34 | void
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| 35 | add_gcable_pointer (char *pointer)
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| 36 | {
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| 37 | gc_pointers ();
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| 38 | add_pointer_to_array (pointer, gcable_pointers_index, gcable_pointers,
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| 39 | gcable_pointers_slots, 10, char *);
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| 40 | }
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| 41 |
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| 42 | /* Grovel the list of info windows and gc-able pointers finding those
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| 43 | node->contents which are collectible, and free them. */
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| 44 | void
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| 45 | gc_pointers (void)
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| 46 | {
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| 47 | register int i, j, k;
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| 48 | INFO_WINDOW *iw;
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| 49 | char **new = (char **)NULL;
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| 50 | int new_index = 0;
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| 51 | int new_slots = 0;
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| 52 |
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| 53 | if (!info_windows || !gcable_pointers_index)
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| 54 | return;
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| 55 |
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| 56 | for (i = 0; (iw = info_windows[i]); i++)
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| 57 | {
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| 58 | for (j = 0; j < iw->nodes_index; j++)
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| 59 | {
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| 60 | NODE *node = iw->nodes[j];
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| 61 |
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| 62 | /* If this node->contents appears in our list of gcable_pointers,
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| 63 | it is not gc-able, so save it. */
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| 64 | for (k = 0; k < gcable_pointers_index; k++)
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| 65 | if (gcable_pointers[k] == node->contents)
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| 66 | {
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| 67 | add_pointer_to_array
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| 68 | (node->contents, new_index, new, new_slots, 10, char *);
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| 69 | break;
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| 70 | }
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| 71 | }
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| 72 | }
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| 73 |
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| 74 | /* We have gathered all of the pointers which need to be saved. Free any
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| 75 | of the original pointers which do not appear in the new list. */
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| 76 | for (i = 0; i < gcable_pointers_index; i++)
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| 77 | {
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| 78 | for (j = 0; j < new_index; j++)
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| 79 | if (gcable_pointers[i] == new[j])
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| 80 | break;
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| 81 |
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| 82 | /* If we got all the way through the new list, then the old pointer
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| 83 | can be garbage collected. */
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| 84 | if (new && !new[j])
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| 85 | free (gcable_pointers[i]);
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| 86 | }
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| 87 |
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| 88 | free (gcable_pointers);
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| 89 | gcable_pointers = new;
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| 90 | gcable_pointers_slots = new_slots;
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| 91 | gcable_pointers_index = new_index;
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| 92 | }
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