Add FOR_EACH style macros

The FOR_EACH() macro will simply traverse the given list. Usage:

FOR_EACH(element, list)
	do_something(element);

The FOR_EACH_UNLINK() macro will traverse the list and unlink each
element. Useful when destroying a whole list. Usage:

FOR_EACH_UNLINK(element, list) {
	destroy(&element);
} END_FOR_EACH_UNLINK(element);

All these macros assume that 'link' is used to connect list elements, as
used in standard ISC list macros.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/util.h b/src/util.h
index 372cd4d..0dd6ee3 100644
--- a/src/util.h
+++ b/src/util.h
@@ -89,4 +89,19 @@
 		dns_name_setbuffer(&name, &name##__buffer);		\
 	} while (0)
 
+#define FOR_EACH(elt, list)						\
+	for ((elt) = HEAD(list); (elt) != NULL; (elt) = NEXT(elt, link))
+
+#define FOR_EACH_UNLINK(elt, list)					     \
+	do {								     \
+		typeof(elt) __next_elt;					     \
+		for (elt = HEAD(list); elt != NULL; elt = NEXT(elt, link)) { \
+			__next_elt = NEXT(elt, link);			     \
+			UNLINK(list, elt, link);
+
+#define END_FOR_EACH_UNLINK(elt)					\
+			elt = __next_elt;				\
+		}							\
+	} while (0)
+
 #endif /* !_LD_UTIL_H_ */