1 files changed, 45 insertions, 0 deletions
diff --git a/src/common.c b/src/common.c
new file mode 100644
index 0000000..41bd145
--- /dev/null
+++ b/src/common.c
@@ -0,0 +1,45 @@
+#include <gran/common.h>
+
+stat place_reg(struct reg *r, struct packet pkt)
+{
+	if (r->busy)
+		return EBUSY;
+
+	r->pkt = pkt;
+	r->busy = true;
+	return OK;
+}
+
+stat copy_reg(struct reg *r, struct reg *s)
+{
+	assert(s->busy);
+	if (r->busy)
+		return EBUSY;
+
+	r->pkt = s->pkt;
+	r->busy = true;
+	s->busy = false;
+	return OK;
+}
+
+void propagate(struct reg *out,
+                      size_t count, struct reg *in[static count],
+                      bool (*sel)(struct reg *r, void *data), void *data)
+{
+	struct reg *r = NULL;
+	for (size_t i = 0; i < count; ++i) {
+		if (!in[i] || !in[i]->busy)
+			continue;
+
+		if (!sel(in[i], data))
+			continue;
+
+		if (!r || r->pkt.timestamp > in[i]->pkt.timestamp)
+			r = in[i];
+	}
+
+	if (!r)
+		return;
+
+	copy_reg(out, r);
+}