MINOR: buffers: provide simple pointer normalization functions

Add buffer_wrap_sub() and buffer_wrap_add() to normalize buffer pointers
after an addition or subtract.

diff --git a/include/proto/buffers.h b/include/proto/buffers.h
index bb2dd45ee46cfd4806d183b56d4fd89fa8685a34..ec8eaab2ba70ff12889aeb41c57c35edb182bd22 100644 (file)
--- a/include/proto/buffers.h
+++ b/include/proto/buffers.h
@@ -87,6 +87,22 @@ static inline int buffer_empty(const struct buffer *buf)
        return !buffer_not_empty(buf);
 }
 
+/* Normalizes a pointer after a subtract */
+static inline char *buffer_wrap_sub(const struct buffer *buf, char *ptr)
+{
+       if (ptr < buf->data)
+               ptr += buf->size;
+       return ptr;
+}
+
+/* Normalizes a pointer after an addition */
+static inline char *buffer_wrap_add(const struct buffer *buf, char *ptr)
+{
+       if (ptr - buf->size >= buf->data)
+               ptr -= buf->size;
+       return ptr;
+}
+
 /* Return the number of reserved bytes in the buffer, which ensures that once
  * all pending data are forwarded, the buffer still has global.tune.maxrewrite
  * bytes free. The result is between 0 and global.maxrewrite, which is itself