LXR qemu/util/range.c

   1/*
   2 * QEMU 64-bit address ranges
   3 *
   4 * Copyright (c) 2015-2016 Red Hat, Inc.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public
   8 * License as published by the Free Software Foundation; either
   9 * version 2 of the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20#include "qemu/osdep.h"
  21#include "qemu/range.h"
  22
  23/*
  24 * Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
  25 * Both @a and @b must not be empty.
  26 */
  27static inline int range_compare(Range *a, Range *b)
  28{
  29    assert(!range_is_empty(a) && !range_is_empty(b));
  30
  31    /* Careful, avoid wraparound */
  32    if (b->lob && b->lob - 1 > a->upb) {
  33        return -1;
  34    }
  35    if (a->lob && a->lob - 1 > b->upb) {
  36        return 1;
  37    }
  38    return 0;
  39}
  40
  41/* Insert @data into @list of ranges; caller no longer owns @data */
  42GList *range_list_insert(GList *list, Range *data)
  43{
  44    GList *l;
  45
  46    assert(!range_is_empty(data));
  47
  48    /* Skip all list elements strictly less than data */
  49    for (l = list; l && range_compare(l->data, data) < 0; l = l->next) {
  50    }
  51
  52    if (!l || range_compare(l->data, data) > 0) {
  53        /* Rest of the list (if any) is strictly greater than @data */
  54        return g_list_insert_before(list, l, data);
  55    }
  56
  57    /* Current list element overlaps @data, merge the two */
  58    range_extend(l->data, data);
  59    g_free(data);
  60
  61    /* Merge any subsequent list elements that now also overlap */
  62    while (l->next && range_compare(l->data, l->next->data) == 0) {
  63        GList *new_l;
  64
  65        range_extend(l->data, l->next->data);
  66        g_free(l->next->data);
  67        new_l = g_list_delete_link(list, l->next);
  68        assert(new_l == list);
  69    }
  70
  71    return list;
  72}
  73