1 files changed, 135 insertions, 0 deletions
diff --git a/src/include/qemu/range.h b/src/include/qemu/range.h
new file mode 100644
index 0000000..cfa021f
--- /dev/null
+++ b/src/include/qemu/range.h
@@ -0,0 +1,135 @@
+#ifndef QEMU_RANGE_H
+#define QEMU_RANGE_H
+
+#include <inttypes.h>
+#include <qemu/typedefs.h>
+#include "qemu/queue.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.
+ */
+
+/* A structure representing a range of addresses. */
+struct Range {
+    uint64_t begin; /* First byte of the range, or 0 if empty. */
+    uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
+};
+
+static inline void range_extend(Range *range, Range *extend_by)
+{
+    if (!extend_by->begin && !extend_by->end) {
+        return;
+    }
+    if (!range->begin && !range->end) {
+        *range = *extend_by;
+        return;
+    }
+    if (range->begin > extend_by->begin) {
+        range->begin = extend_by->begin;
+    }
+    /* Compare last byte in case region ends at ~0x0LL */
+    if (range->end - 1 < extend_by->end - 1) {
+        range->end = extend_by->end;
+    }
+}
+
+/* Get last byte of a range from offset + length.
+ * Undefined for ranges that wrap around 0. */
+static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
+{
+    return offset + len - 1;
+}
+
+/* Check whether a given range covers a given byte. */
+static inline int range_covers_byte(uint64_t offset, uint64_t len,
+                                    uint64_t byte)
+{
+    return offset <= byte && byte <= range_get_last(offset, len);
+}
+
+/* Check whether 2 given ranges overlap.
+ * Undefined if ranges that wrap around 0. */
+static inline int ranges_overlap(uint64_t first1, uint64_t len1,
+                                 uint64_t first2, uint64_t len2)
+{
+    uint64_t last1 = range_get_last(first1, len1);
+    uint64_t last2 = range_get_last(first2, len2);
+
+    return !(last2 < first1 || last1 < first2);
+}
+
+/* 0,1 can merge with 1,2 but don't overlap */
+static inline bool ranges_can_merge(Range *range1, Range *range2)
+{
+    return !(range1->end < range2->begin || range2->end < range1->begin);
+}
+
+static inline int range_merge(Range *range1, Range *range2)
+{
+    if (ranges_can_merge(range1, range2)) {
+        if (range1->end < range2->end) {
+            range1->end = range2->end;
+        }
+        if (range1->begin > range2->begin) {
+            range1->begin = range2->begin;
+        }
+        return 0;
+    }
+
+    return -1;
+}
+
+static inline 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;
+}
+
+static inline gint range_compare(gconstpointer a, gconstpointer b)
+{
+    Range *ra = (Range *)a, *rb = (Range *)b;
+    if (ra->begin == rb->begin && ra->end == rb->end) {
+        return 0;
+    } else if (range_get_last(ra->begin, ra->end) <
+               range_get_last(rb->begin, rb->end)) {
+        return -1;
+    } else {
+        return 1;
+    }
+}
+
+#endif