From b956a2be1c65de13972f8a98111d507660f4d7e9 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Wed, 8 Aug 2018 16:00:07 -0400
Subject: [PATCH] common/color: Get rid of undefined behavior

Gets rid of type punning via reinterpret_cast within functions. Instead,
we use memcpy to transfer the contents across types.
---
 src/common/color.h | 36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/common/color.h b/src/common/color.h
index 24a445dac..2e56af5a9 100644
--- a/src/common/color.h
+++ b/src/common/color.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <cstring>
+
 #include "common/common_types.h"
 #include "common/swap.h"
 #include "common/vector_math.h"
@@ -83,7 +85,8 @@ inline const Math::Vec4<u8> DecodeRG8(const u8* bytes) {
  * @return Result color decoded as Math::Vec4<u8>
  */
 inline const Math::Vec4<u8> DecodeRGB565(const u8* bytes) {
-    const u16_le pixel = *reinterpret_cast<const u16_le*>(bytes);
+    u16_le pixel;
+    std::memcpy(&pixel, bytes, sizeof(pixel));
     return {Convert5To8((pixel >> 11) & 0x1F), Convert6To8((pixel >> 5) & 0x3F),
             Convert5To8(pixel & 0x1F), 255};
 }
@@ -94,7 +97,8 @@ inline const Math::Vec4<u8> DecodeRGB565(const u8* bytes) {
  * @return Result color decoded as Math::Vec4<u8>
  */
 inline const Math::Vec4<u8> DecodeRGB5A1(const u8* bytes) {
-    const u16_le pixel = *reinterpret_cast<const u16_le*>(bytes);
+    u16_le pixel;
+    std::memcpy(&pixel, bytes, sizeof(pixel));
     return {Convert5To8((pixel >> 11) & 0x1F), Convert5To8((pixel >> 6) & 0x1F),
             Convert5To8((pixel >> 1) & 0x1F), Convert1To8(pixel & 0x1)};
 }
@@ -105,7 +109,8 @@ inline const Math::Vec4<u8> DecodeRGB5A1(const u8* bytes) {
  * @return Result color decoded as Math::Vec4<u8>
  */
 inline const Math::Vec4<u8> DecodeRGBA4(const u8* bytes) {
-    const u16_le pixel = *reinterpret_cast<const u16_le*>(bytes);
+    u16_le pixel;
+    std::memcpy(&pixel, bytes, sizeof(pixel));
     return {Convert4To8((pixel >> 12) & 0xF), Convert4To8((pixel >> 8) & 0xF),
             Convert4To8((pixel >> 4) & 0xF), Convert4To8(pixel & 0xF)};
 }
@@ -116,7 +121,9 @@ inline const Math::Vec4<u8> DecodeRGBA4(const u8* bytes) {
  * @return Depth value as an u32
  */
 inline u32 DecodeD16(const u8* bytes) {
-    return *reinterpret_cast<const u16_le*>(bytes);
+    u16_le data;
+    std::memcpy(&data, bytes, sizeof(data));
+    return data;
 }
 
 /**
@@ -175,8 +182,10 @@ inline void EncodeRG8(const Math::Vec4<u8>& color, u8* bytes) {
  * @param bytes Destination pointer to store encoded color
  */
 inline void EncodeRGB565(const Math::Vec4<u8>& color, u8* bytes) {
-    *reinterpret_cast<u16_le*>(bytes) =
+    const u16_le data =
         (Convert8To5(color.r()) << 11) | (Convert8To6(color.g()) << 5) | Convert8To5(color.b());
+
+    std::memcpy(bytes, &data, sizeof(data));
 }
 
 /**
@@ -185,9 +194,10 @@ inline void EncodeRGB565(const Math::Vec4<u8>& color, u8* bytes) {
  * @param bytes Destination pointer to store encoded color
  */
 inline void EncodeRGB5A1(const Math::Vec4<u8>& color, u8* bytes) {
-    *reinterpret_cast<u16_le*>(bytes) = (Convert8To5(color.r()) << 11) |
-                                        (Convert8To5(color.g()) << 6) |
-                                        (Convert8To5(color.b()) << 1) | Convert8To1(color.a());
+    const u16_le data = (Convert8To5(color.r()) << 11) | (Convert8To5(color.g()) << 6) |
+                        (Convert8To5(color.b()) << 1) | Convert8To1(color.a());
+
+    std::memcpy(bytes, &data, sizeof(data));
 }
 
 /**
@@ -196,9 +206,10 @@ inline void EncodeRGB5A1(const Math::Vec4<u8>& color, u8* bytes) {
  * @param bytes Destination pointer to store encoded color
  */
 inline void EncodeRGBA4(const Math::Vec4<u8>& color, u8* bytes) {
-    *reinterpret_cast<u16_le*>(bytes) = (Convert8To4(color.r()) << 12) |
-                                        (Convert8To4(color.g()) << 8) |
-                                        (Convert8To4(color.b()) << 4) | Convert8To4(color.a());
+    const u16 data = (Convert8To4(color.r()) << 12) | (Convert8To4(color.g()) << 8) |
+                     (Convert8To4(color.b()) << 4) | Convert8To4(color.a());
+
+    std::memcpy(bytes, &data, sizeof(data));
 }
 
 /**
@@ -207,7 +218,8 @@ inline void EncodeRGBA4(const Math::Vec4<u8>& color, u8* bytes) {
  * @param bytes Pointer where to store the encoded value
  */
 inline void EncodeD16(u32 value, u8* bytes) {
-    *reinterpret_cast<u16_le*>(bytes) = value & 0xFFFF;
+    const u16_le data = static_cast<u16>(value);
+    std::memcpy(bytes, &data, sizeof(data));
 }
 
 /**