[Qemu-devel] [PATCH RFC 08/13] range: add Range structure

["Michael S. Tsirkin" <mst@redhat.com>]

Sometimes we need to pass ranges around, add a
handy structure for this purpose.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/qemu/range.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/qemu/range.h b/include/qemu/range.h
index 3502372..4bcd346 100644
--- a/include/qemu/range.h
+++ b/include/qemu/range.h
@@ -1,6 +1,28 @@
 #ifndef QEMU_RANGE_H
 #define QEMU_RANGE_H
 
+#include <inttypes.h>
+
+/*
+ * Operations on 64 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. */
+};
+typedef struct Range Range;
+
+/* verify that range is not empty and does not overlap */
+static inline bool range_valid(struct Range *range)
+{
+    return range->begin + 1 <= range->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)
-- 
MST