[PATCH v2 3/3] [RFC] Add a sorted-list API for use-cases that require to get the element index.

@@ -1,7 +1,7 @@
 #define declare_sorted_array(MAYBESTATIC,ELEMTYPE,LIST,CMP,INIT)	\
 MAYBESTATIC ELEMTYPE *LIST;						\
 MAYBESTATIC int LIST##_nr, LIST##_alloc;				\
-MAYBESTATIC ELEMTYPE *locate_##LIST(void *data, int insert_ok)		\
+MAYBESTATIC int locate_##LIST##_idx(void *data, int insert_ok)		\
 {									\
 	int first, last;						\
 									\

@@ -12,7 +12,7 @@ MAYBESTATIC ELEMTYPE *locate_##LIST(void *data, int insert_ok)		\
 		ELEMTYPE *nextelem = &(LIST[next]);			\
 		int cmp = CMP(data, nextelem);				\
 		if (!cmp)						\
-			return nextelem;				\
+			return next;					\
 		if (cmp < 0) {						\
 			last = next;					\
 			continue;					\

@@ -21,7 +21,7 @@ MAYBESTATIC ELEMTYPE *locate_##LIST(void *data, int insert_ok)		\
 	}								\
 	/* not found */							\
 	if (!insert_ok)							\
-		return NULL;						\
+		return -first-1;					\
 	/* insert to make it at "first" */				\
 	if (LIST##_alloc <= LIST##_nr) {				\
 		LIST##_alloc = alloc_nr(LIST##_alloc);			\

@@ -32,5 +32,12 @@ MAYBESTATIC ELEMTYPE *locate_##LIST(void *data, int insert_ok)		\
 		memmove(LIST + first + 1, LIST + first,			\
 			(LIST##_nr - first - 1) * sizeof(*LIST));	\
 	INIT(&LIST[first], data);					\
-	return &(LIST[first]);						\
+	return first;							\
+}									\
+MAYBESTATIC ELEMTYPE *locate_##LIST(void *data, int insert_ok)		\
+{									\
+	int idx = locate_##LIST##_idx(data, insert_ok);			\
+	if (idx < 0)							\
+		return NULL;						\
+	return &(LIST[idx]);						\
 }