1 files changed, 72 insertions, 0 deletions
diff --git a/util/range.c b/util/range.c
new file mode 100644
index 000000000..098d9d2dc
--- /dev/null
+++ b/util/range.c
@@ -0,0 +1,72 @@
+/*
+ * QEMU 64-bit address ranges
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This program 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 program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; 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.
+ */
+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;
+    }
+    if (a->lob && a->lob - 1 > b->upb) {
+        return 1;
+    }
+    return 0;
+}
+
+/* Insert @data into @list of ranges; caller no longer owns @data */
+GList *range_list_insert(GList *list, Range *data)
+{
+    GList *l;
+
+    assert(!range_is_empty(data));
+
+    /* Skip all list elements strictly less than data */
+    for (l = list; l && range_compare(l->data, data) < 0; l = l->next) {
+    }
+
+    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);
+    }
+
+    /* 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;
+}