From e5a93d4ca0e1bfae91a05e11dcdd6a43232f907b Mon Sep 17 00:00:00 2001
From: Alex Kaminskii <alex@openreplay.com>
Date: Tue, 14 Feb 2023 14:04:31 +0100
Subject: [PATCH] feat(backend): reader maintains multibyte type

---
 backend/pkg/messages/primitives.go | 10 ++++++++++
 backend/pkg/messages/reader.go     |  6 ++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/backend/pkg/messages/primitives.go b/backend/pkg/messages/primitives.go
index 3e47a3943..921239287 100644
--- a/backend/pkg/messages/primitives.go
+++ b/backend/pkg/messages/primitives.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"math"
 )
 
 var (
@@ -50,6 +51,15 @@ func WriteUint(v uint64, buf []byte, p int) int {
 	return p + 1
 }
 
+func ByteSizeUint(v uint64) int {
+	if v == 0 {
+		return 1
+	}
+	nBits := math.Floor(math.Log2(float64(v))) + 1
+	nBytes := math.Ceil(nBits / 7)
+	return int(nBytes)
+}
+
 func ReadInt(reader io.Reader) (int64, error) {
 	ux, err := ReadUint(reader)
 	x := int64(ux >> 1)
diff --git a/backend/pkg/messages/reader.go b/backend/pkg/messages/reader.go
index 1e9fa42db..436876e55 100644
--- a/backend/pkg/messages/reader.go
+++ b/backend/pkg/messages/reader.go
@@ -70,13 +70,15 @@ func (m *messageReaderImpl) Parse() (err error) {
 			}
 
 			// Dirty hack to avoid extra memory allocation
-			m.data[curr-1] = uint8(m.msgType)
+			mTypeByteSize := ByteSizeUint(m.msgType)
+			from := int(curr) - mTypeByteSize
+			WriteUint(m.msgType, m.data, from)
 
 			// Add message meta to list
 			m.list = append(m.list, &MessageMeta{
 				msgType: m.msgType,
 				msgSize: m.msgSize + 1,
-				msgFrom: uint64(curr - 1),
+				msgFrom: uint64(from),
 			})
 
 			// Update data pointer