[master] 1e10f10b8 miniobj: Allocate objects with a flexible array

[Dridi Boukelmoune]

commit 1e10f10b8c364262c0eebe6326d1133e5460c297
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Mon Jul 10 12:21:44 2023 +0200

    miniobj: Allocate objects with a flexible array

diff --git a/include/miniobj.h b/include/miniobj.h
index 8babaa251..832998019 100644
--- a/include/miniobj.h
+++ b/include/miniobj.h
@@ -30,6 +30,17 @@
 			(to)->magic = (type_magic);			\
 	} while (0)
 
+#define ALLOC_FLEX_OBJ(to, fld, len, type_magic)			\
+	do {								\
+		v_static_assert(					\
+		    sizeof *(to) == offsetof(typeof(*(to)), fld),	\
+		    "the last field must be a flexible array");		\
+		(to) = calloc(1,					\
+		    sizeof *(to) + ((len) * sizeof *((to)->fld)));	\
+		if ((to) != NULL)					\
+			(to)->magic = (type_magic);			\
+	} while (0)
+
 #define FREE_OBJ(to)							\
 	do {								\
 		ZERO_OBJ(&(to)->magic, sizeof (to)->magic);		\