+#define GH_INIT(ch) (ch)->init()
+#define GH_CLASS(h) (h)->ops->c
+#define GH_HASH(h, p, sz) (h)->ops->hash((h), (p), (sz))
+#define GH_DONE(h, buf) (h)->ops->done((h), (buf))
+#define GH_DESTROY(h) (h)->ops->destroy((h))
+#define GH_COPY(h) (h)->ops->copy((h))
+