+
+/** 640K ought to be enough for everybody ;) */
+#define FILTER_MAX_PENDING (640 * 1024)
+
+int prepare_filter_node(struct filter_node *fn)
+{
+ struct btr_node *btrn = fn->btrn;
+ size_t iqs;
+
+ if (btr_eof(btrn))
+ return -E_FC_EOF;
+ if (btr_bytes_pending(btrn) > FILTER_MAX_PENDING)
+ return 0;
+ iqs = btr_get_input_queue_size(btrn);
+ if (iqs < fn->min_iqs && !btr_no_parent(btrn))
+ return 0;
+ assert(iqs != 0);
+ /* avoid "buffer too small" errors from the decoder */
+ btr_merge(btrn, fn->min_iqs);
+ return 1;
+}
+
+void generic_filter_pre_select(struct sched *s, struct task *t)
+{
+ struct filter_node *fn = container_of(t, struct filter_node, task);
+ size_t iqs = btr_get_input_queue_size(fn->btrn);
+
+ t->error = 0;
+ if (iqs < fn->min_iqs)
+ return;
+ if (btr_bytes_pending(fn->btrn) > FILTER_MAX_PENDING)
+ return; /* FIXME, should use reasonable bound on timeout */
+ s->timeout.tv_sec = 0;
+ s->timeout.tv_usec = 1;
+}
+