From 38077cf6f25cb345092638fadcc3afce82898936 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Thu, 14 Nov 2024 11:22:15 -0500
Subject: total-order multicast pseudocode

---
 doc/tomulticast.pseudo | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 doc/tomulticast.pseudo

(limited to 'doc/tomulticast.pseudo')

diff --git a/doc/tomulticast.pseudo b/doc/tomulticast.pseudo
new file mode 100644
index 0000000..332ba32
--- /dev/null
+++ b/doc/tomulticast.pseudo
@@ -0,0 +1,35 @@
+type message struct {
+	seq int
+	payload
+}
+
+class sequencer {
+	var seq = 0
+
+	// Receive a request from the FE.
+	// Attach sequence number and multicast to RMs.
+	on rUnicastReceive(payload) {
+		rMulticastSend(message{seq, payload})
+		seq++
+	}
+}
+
+class receiver {
+	var seq = 0
+	var holdback Queue[message]
+
+	// Receive from sequencer.
+	on rMulticastReceive(m message) {
+		append(holdback, m)
+		trydeliver()
+	}
+
+	trydeliver() {
+		if t.e. m in holdback s.t. m.seq == seq+1 {
+			remove(m, holdback)
+			deliver(m)
+			seq++
+			trydeliver()
+		}
+	}
+}
-- 
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