From 8a15c0b0741568a2b4b0d473b83de227bcfdb705 Mon Sep 17 00:00:00 2001
From: "M. Sz" <mszeptuch@protonmail.com>
Date: Wed, 10 Feb 2021 08:24:53 +0100
Subject: [PATCH 1/3] hotfix: cof encoder: coding weapon class

---
 d2common/d2fileformats/d2cof/cof.go       | 11 +++++++++--
 d2common/d2fileformats/d2cof/cof_layer.go | 13 ++++++-------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/d2common/d2fileformats/d2cof/cof.go b/d2common/d2fileformats/d2cof/cof.go
index 5b119b47..3b47c4a3 100644
--- a/d2common/d2fileformats/d2cof/cof.go
+++ b/d2common/d2fileformats/d2cof/cof.go
@@ -121,7 +121,6 @@ func (c *COF) Unmarshal(fileData []byte) error {
 		layer.Transparent = b[layerTransparent] > 0
 		layer.DrawEffect = d2enum.DrawEffect(b[layerDrawEffect])
 
-		layer.weaponClassByte = b[layerWeaponClass:]
 		layer.WeaponClass = d2enum.WeaponClassFromString(strings.TrimSpace(strings.ReplaceAll(
 			string(b[layerWeaponClass:]), badCharacter, "")))
 
@@ -193,7 +192,15 @@ func (c *COF) Marshal() []byte {
 
 		sw.PushBytes(byte(c.CofLayers[i].DrawEffect))
 
-		sw.PushBytes(c.CofLayers[i].weaponClassByte...)
+		s := c.CofLayers[i].WeaponClass.String()
+
+		for j := 0; j < 4; j++ {
+			if j < len(s) {
+				sw.PushBytes(s[j])
+			} else {
+				sw.PushBytes(0)
+			}
+		}
 	}
 
 	for _, i := range c.AnimationFrames {
diff --git a/d2common/d2fileformats/d2cof/cof_layer.go b/d2common/d2fileformats/d2cof/cof_layer.go
index 2658e691..8a09f9c1 100644
--- a/d2common/d2fileformats/d2cof/cof_layer.go
+++ b/d2common/d2fileformats/d2cof/cof_layer.go
@@ -4,11 +4,10 @@ import "github.com/OpenDiablo2/OpenDiablo2/d2common/d2enum"
 
 // CofLayer is a structure that represents a single layer in a COF file.
 type CofLayer struct {
-	Type            d2enum.CompositeType
-	Shadow          byte
-	Selectable      bool
-	Transparent     bool
-	DrawEffect      d2enum.DrawEffect
-	WeaponClass     d2enum.WeaponClass
-	weaponClassByte []byte
+	Type        d2enum.CompositeType
+	Shadow      byte
+	Selectable  bool
+	Transparent bool
+	DrawEffect  d2enum.DrawEffect
+	WeaponClass d2enum.WeaponClass
 }

From 10103530716f2a0293f990feca3358303327999f Mon Sep 17 00:00:00 2001
From: "M. Sz" <mszeptuch@protonmail.com>
Date: Wed, 10 Feb 2021 12:35:35 +0100
Subject: [PATCH 2/3] hotfix: d2cof encoder: removed magic number (len of
 weapon class)

---
 d2common/d2fileformats/d2cof/cof.go | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/d2common/d2fileformats/d2cof/cof.go b/d2common/d2fileformats/d2cof/cof.go
index 3b47c4a3..fa9b1002 100644
--- a/d2common/d2fileformats/d2cof/cof.go
+++ b/d2common/d2fileformats/d2cof/cof.go
@@ -30,6 +30,10 @@ const (
 	layerWeaponClass
 )
 
+const (
+	layerWeaponClassLength = 4
+)
+
 const (
 	badCharacter = string(byte(0))
 )
@@ -192,11 +196,11 @@ func (c *COF) Marshal() []byte {
 
 		sw.PushBytes(byte(c.CofLayers[i].DrawEffect))
 
-		s := c.CofLayers[i].WeaponClass.String()
+		weaponClassString := c.CofLayers[i].WeaponClass.String()
 
-		for j := 0; j < 4; j++ {
-			if j < len(s) {
-				sw.PushBytes(s[j])
+		for letter := 0; letter < layerWeaponClassLength; letter++ {
+			if letter < len(weaponClassString) {
+				sw.PushBytes(weaponClassString[letter])
 			} else {
 				sw.PushBytes(0)
 			}

From 7d0eeb0fd3a0bbb6a4cfda0cd05fc3bb9f537b0f Mon Sep 17 00:00:00 2001
From: "M. Sz" <mszeptuch@protonmail.com>
Date: Wed, 10 Feb 2021 12:59:07 +0100
Subject: [PATCH 3/3] hotfix: d2cof encoder: changed way of pushing weapon
 class

---
 d2common/d2fileformats/d2cof/cof.go | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/d2common/d2fileformats/d2cof/cof.go b/d2common/d2fileformats/d2cof/cof.go
index fa9b1002..ceb9ab11 100644
--- a/d2common/d2fileformats/d2cof/cof.go
+++ b/d2common/d2fileformats/d2cof/cof.go
@@ -30,10 +30,6 @@ const (
 	layerWeaponClass
 )
 
-const (
-	layerWeaponClassLength = 4
-)
-
 const (
 	badCharacter = string(byte(0))
 )
@@ -196,15 +192,22 @@ func (c *COF) Marshal() []byte {
 
 		sw.PushBytes(byte(c.CofLayers[i].DrawEffect))
 
-		weaponClassString := c.CofLayers[i].WeaponClass.String()
+		const (
+			maxCodeLength = 3 // we assume item codes to look like 'hax' or 'kit'
+			terminator    = 0
+		)
 
-		for letter := 0; letter < layerWeaponClassLength; letter++ {
-			if letter < len(weaponClassString) {
-				sw.PushBytes(weaponClassString[letter])
-			} else {
-				sw.PushBytes(0)
+		weaponCode := c.CofLayers[i].WeaponClass.String()
+
+		for idx, letter := range weaponCode {
+			if idx > maxCodeLength {
+				break
 			}
+
+			sw.PushBytes(byte(letter))
 		}
+
+		sw.PushBytes(terminator)
 	}
 
 	for _, i := range c.AnimationFrames {