2 files changed, 82 insertions, 0 deletions
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 45f8794864..96cb1e0e58 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -34,3 +34,4 @@ util-obj-y += base64.o
 util-obj-y += log.o
 util-obj-y += qdist.o
 util-obj-y += qht.o
+util-obj-y += range.o
diff --git a/util/range.c b/util/range.c
new file mode 100644
index 0000000000..f775f2e673
--- /dev/null
+++ b/util/range.c
@@ -0,0 +1,81 @@
+/*
+ * 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.
+ */
+
+/* 0,1 can merge with 1,2 but don't overlap */
+static bool ranges_can_merge(Range *range1, Range *range2)
+{
+    return !(range1->end < range2->begin || range2->end < range1->begin);
+}
+
+static void range_merge(Range *range1, Range *range2)
+{
+    if (range1->end < range2->end) {
+        range1->end = range2->end;
+    }
+    if (range1->begin > range2->begin) {
+        range1->begin = range2->begin;
+    }
+}
+
+GList *g_list_insert_sorted_merged(GList *list, gpointer data,
+                                   GCompareFunc func)
+{
+    GList *l, *next = NULL;
+    Range *r, *nextr;
+
+    if (!list) {
+        list = g_list_insert_sorted(list, data, func);
+        return list;
+    }
+
+    nextr = data;
+    l = list;
+    while (l && l != next && nextr) {
+        r = l->data;
+        if (ranges_can_merge(r, nextr)) {
+            range_merge(r, nextr);
+            l = g_list_remove_link(l, next);
+            next = g_list_next(l);
+            if (next) {
+                nextr = next->data;
+            } else {
+                nextr = NULL;
+            }
+        } else {
+            l = g_list_next(l);
+        }
+    }
+
+    if (!l) {
+        list = g_list_insert_sorted(list, data, func);
+    }
+
+    return list;
+}