From f1a8f2714cae7d2d533ad45cfcc111a39c6705af Mon Sep 17 00:00:00 2001
From: Nicolas Lacasse <nlacasse@google.com>
Date: Thu, 6 Apr 2023 09:19:09 -0700
Subject: [PATCH] Add marshal.MarshalAll() and marshal.TotalSize().

These util methods make it easier to work with multiple marshallable structs at
once.

PiperOrigin-RevId: 522353552
---
 pkg/marshal/util.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/pkg/marshal/util.go b/pkg/marshal/util.go
index c1e5475bd..959d6922e 100644
--- a/pkg/marshal/util.go
+++ b/pkg/marshal/util.go
@@ -21,3 +21,24 @@ func Marshal(m Marshallable) []byte {
 	m.MarshalUnsafe(buf)
 	return buf
 }
+
+// MarshalAll returns the serialized contents of all ms in a newly allocated
+// byte slice.
+func MarshalAll(ms []Marshallable) []byte {
+	buf := make([]byte, TotalSize(ms))
+	var written int
+	for _, m := range ms {
+		m.MarshalUnsafe(buf[written:])
+		written += m.SizeBytes()
+	}
+	return buf
+}
+
+// TotalSize returns the total size of all ms.
+func TotalSize(ms []Marshallable) int {
+	var size int
+	for _, m := range ms {
+		size += m.SizeBytes()
+	}
+	return size
+}