1 files changed, 39 insertions, 0 deletions
diff --git a/nss/slist.h b/nss/slist.h
new file mode 100644
index 0000000..cd031ee
--- /dev/null
+++ b/nss/slist.h
@@ -0,0 +1,39 @@
+
+struct slist { struct slist *next; };
+
+void slist_init(struct slist* self);
+bool slist_null(struct slist* self);
+bool slist_non_null(struct slist* self);
+size_t slist_length(struct slist* self);
+void slist_extend(struct slist* self, struct slist* rhs);
+
+#define container_of(PTR, TYPE, MEMBER) \
+  (TYPE *)((char *)(PTR) - ((ptrdiff_t) &((TYPE*)0)->MEMBER))
+
+/* FUN should return false to break iteration. */
+/* NB: Comma-swallowing paste of gnu-style named variadic macro argument. */
+#define slist_metafor(TYPE, MEMBER, PTR, BODY) { \
+  struct slist *__slist_head = &((PTR)->MEMBER); \
+  struct slist *__slist_iter = __slist_head->next; \
+  struct slist *__slist_next; \
+  while(__slist_iter != __slist_head) { \
+        __slist_next = __slist_iter->next; \
+        TYPE* __value_ptr = container_of(__slist_iter, TYPE, MEMBER); \
+        BODY; \
+        __slist_iter = __slist_next; \
+  } \
+}
+
+#define slist_search(TYPE, MEMBER, PTR, FOUND_LABEL, NOTFOUND_LABEL, FUN, \
+  COOKIE...) \
+  slist_metafor(TYPE, MEMBER, PTR, \
+    { if(!(FUN)(__value_ptr, ##COOKIE)) goto FOUND_LABEL; } \
+  ) \
+  goto NOTFOUND_LABEL;
+
+#define slist_while(TYPE, MEMBER, PTR, ERR_LABEL, FUN, COOKIE...) \
+  slist_metafor(TYPE, MEMBER, PTR, \
+    { if((FUN)(__value_ptr, ##COOKIE)) goto ERR_LABEL; }) \
+
+#define slist_for(TYPE, MEMBER, PTR, FUN, COOKIE...) \
+  slist_metafor(TYPE, MEMBER, PTR, { (FUN)(__value_ptr, ##COOKIE); })