1 files changed, 76 insertions, 0 deletions
diff --git a/util/range.c b/util/range.c
new file mode 100644
index 0000000000..e90c988dbf
--- /dev/null
+++ b/util/range.c
@@ -0,0 +1,76 @@
+/*
+ * 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"
+
+/*
+ * Operations on 64 bit address ranges.
+ * Notes:
+ *   - ranges must not wrap around 0, but can include the last byte ~0x0LL.
+ *   - this can not represent a full 0 to ~0x0LL range.
+ */
+
+/* Return -1 if @a < @b, 1 if greater, and 0 if they touch or overlap. */
+static inline int range_compare(Range *a, Range *b)
+{
+    /* Zero a->end is 2**64, and therefore not less than any b->begin */
+    if (a->end && a->end < b->begin) {
+        return -1;
+    }
+    if (b->end && a->begin > b->end) {
+        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;
+
+    /* Range lists require no empty ranges */
+    assert(data->begin < data->end || (data->begin && !data->end));
+
+    /* 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;
+}