qemu/util/range.c

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/*
* QEMU 64-bit address ranges
*
* Copyright (c) 2015-2016 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "qemu/range.h"
/*
* Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
* Both @a and @b must not be empty.
*/
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static inline int range_compare(Range *a, Range *b)
{
assert(!range_is_empty(a) && !range_is_empty(b));
/* Careful, avoid wraparound */
if (b->lob && b->lob - 1 > a->upb) {
return -1;
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}
if (a->lob && a->lob - 1 > b->upb) {
return 1;
}
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return 0;
}
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/* Insert @data into @list of ranges; caller no longer owns @data */
GList *range_list_insert(GList *list, Range *data)
{
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GList *l;
assert(!range_is_empty(data));
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/* Skip all list elements strictly less than data */
for (l = list; l && range_compare(l->data, data) < 0; l = l->next) {
}
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if (!l || range_compare(l->data, data) > 0) {
/* Rest of the list (if any) is strictly greater than @data */
return g_list_insert_before(list, l, data);
}
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/* Current list element overlaps @data, merge the two */
range_extend(l->data, data);
g_free(data);
/* Merge any subsequent list elements that now also overlap */
while (l->next && range_compare(l->data, l->next->data) == 0) {
GList *new_l;
range_extend(l->data, l->next->data);
g_free(l->next->data);
new_l = g_list_delete_link(list, l->next);
assert(new_l == list);
}
return list;
}