Patchwork [v3,1/4] range: add Range structure

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Submitter Michael S. Tsirkin
Date June 18, 2013, 2:17 p.m.
Message ID <1371564986-11136-2-git-send-email-mst@redhat.com>
Download mbox | patch
Permalink /patch/252356/
State New
Headers show

Comments

Michael S. Tsirkin - June 18, 2013, 2:17 p.m.
Sometimes we need to pass ranges around, add a
handy structure for this purpose.

Note: memory.c defines its own concept of AddrRange structure for
working with 128 addresses.  It's necessary there for doing range math.
This is not needed for most users: struct Range is
much simpler, and is only used for passing the range around.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/qemu/range.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Patch

diff --git a/include/qemu/range.h b/include/qemu/range.h
index 3502372..b76cc0d 100644
--- a/include/qemu/range.h
+++ b/include/qemu/range.h
@@ -1,6 +1,22 @@ 
 #ifndef QEMU_RANGE_H
 #define QEMU_RANGE_H
 
+#include <inttypes.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. */
+};
+typedef struct Range Range;
+
 /* 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)