Add the container_of() macro to macro.h

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/common/macros.h b/src/common/macros.h
index 90849ed30ae5e543a577f9214bc33152864751f8..7eaf27cdf3787cbf02d5c4fc2bc48eb43632b734 100644 (file)
--- a/src/common/macros.h
+++ b/src/common/macros.h
@@ -20,6 +20,7 @@
 #define _MACROS_H
 
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 #include <common/compat/string.h>
 
@@ -58,6 +59,14 @@ void *zmalloc(size_t len)
 #define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
 #endif
 
+#ifndef container_of
+#define container_of(ptr, type, member)                                        \
+       ({                                                              \
+               const typeof(((type *)NULL)->member) * __ptr = (ptr);   \
+               (type *)((char *)__ptr - offsetof(type, member));       \
+       })
+#endif
+
 #ifndef max
 #define max(a, b) ((a) > (b) ? (a) : (b))
 #endif