[PATCH 3/3] boilerplate/avl: fix NULL link representation in pshared mode - take #2

[Philippe Gerum via Xenomai]

Since zero is the offset pointing at the AVL tree anchor, it cannot be
used for representing a NULL link. Use (ptrdiff_t)-1 instead.

Signed-off-by: Philippe Gerum <r...@xenomai.org>
---
 include/boilerplate/avl-inner.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/boilerplate/avl-inner.h b/include/boilerplate/avl-inner.h
index 8e4de8487..9c0576213 100644
--- a/include/boilerplate/avl-inner.h
+++ b/include/boilerplate/avl-inner.h
@@ -105,14 +105,14 @@ shavlh_link(const struct shavl *const avl,
            const struct shavlh *const holder, unsigned int dir)
 {
        ptrdiff_t offset = holder->link[avl_type2index(dir)].offset;
-       return offset ? (void *)avl + offset : NULL;
+       return offset == (ptrdiff_t)-1 ? NULL : (void *)avl + offset;
 }
 
 static inline void
 shavlh_set_link(struct shavl *const avl, struct shavlh *lhs,
                int dir, struct shavlh *rhs)
 {
-       ptrdiff_t offset = rhs ? (void *)rhs - (void *)avl : 0;
+       ptrdiff_t offset = rhs ? (void *)rhs - (void *)avl : (ptrdiff_t)-1;
        lhs->link[avl_type2index(dir)].offset = offset;
 }
 
@@ -120,13 +120,13 @@ static inline
 struct shavlh *shavl_end(const struct shavl *const avl, int dir)
 {
        ptrdiff_t offset = avl->end[avl_type2index(dir)].offset;
-       return offset ? (void *)avl + offset : NULL;
+       return offset == (ptrdiff_t)-1 ? NULL : (void *)avl + offset;
 }
 
 static inline void
 shavl_set_end(struct shavl *const avl, int dir, struct shavlh *holder)
 {
-       ptrdiff_t offset = holder ? (void *)holder - (void *)avl : 0;
+       ptrdiff_t offset = holder ? (void *)holder - (void *)avl : 
(ptrdiff_t)-1;
        avl->end[avl_type2index(dir)].offset = offset;
 }
 
-- 
2.21.0