From 9949da4f926a2e53e4f04e12041ac6831bd9c22c Mon Sep 17 00:00:00 2001
From: Mauller <26652186+Mauller@users.noreply.github.com>
Date: Sat, 5 Jul 2025 09:50:01 +0100
Subject: [PATCH] [CORE] Refactor XferCRC to make it branchless and to remove
 winsock dependency

---
 Core/GameEngine/Include/Common/XferCRC.h      |  2 +-
 .../Source/Common/System/XferCRC.cpp          | 47 ++++++-------------
 2 files changed, 16 insertions(+), 33 deletions(-)

diff --git a/Core/GameEngine/Include/Common/XferCRC.h b/Core/GameEngine/Include/Common/XferCRC.h
index 5c07d5bc4a..35bee5c6be 100644
--- a/Core/GameEngine/Include/Common/XferCRC.h
+++ b/Core/GameEngine/Include/Common/XferCRC.h
@@ -64,7 +64,7 @@ class XferCRC : public Xfer
 
 	virtual void xferImplementation( void *data, Int dataSize );
 
-	void addCRC( UnsignedInt val );								///< CRC a 4-byte block
+	inline void addCRC( UnsignedInt val );								///< CRC a 4-byte block
 
 	UnsignedInt m_crc;
 
diff --git a/Core/GameEngine/Source/Common/System/XferCRC.cpp b/Core/GameEngine/Source/Common/System/XferCRC.cpp
index b90e643386..8d505ce6df 100644
--- a/Core/GameEngine/Source/Common/System/XferCRC.cpp
+++ b/Core/GameEngine/Source/Common/System/XferCRC.cpp
@@ -34,7 +34,7 @@
 #include "Common/XferDeepCRC.h"
 #include "Common/crc.h"
 #include "Common/Snapshot.h"
-#include "winsock2.h" // for htonl
+#include "utility/endian_compat.h"
 
 //-------------------------------------------------------------------------------------------------
 //-------------------------------------------------------------------------------------------------
@@ -97,22 +97,8 @@ void XferCRC::endBlock( void )
 //-------------------------------------------------------------------------------------------------
 void XferCRC::addCRC( UnsignedInt val )
 {
-	int hibit;
 
-	val = htonl(val);
-
-	if (m_crc & 0x80000000)
-	{
-		hibit = 1;
-	}
-	else
-	{
-		hibit = 0;
-	}
-
-	m_crc <<= 1;
-	m_crc += val;
-	m_crc += hibit;
+	m_crc = (m_crc << 1) + htobe(val) +((m_crc >> 31) & 0x01);
 
 }  // end addCRC
 
@@ -140,30 +126,27 @@ void XferCRC::xferSnapshot( Snapshot *snapshot )
 void XferCRC::xferImplementation( void *data, Int dataSize )
 {
 
-	if (!data || dataSize < 1)
-	{
-		return;
-	}
-
 	const UnsignedInt *uintPtr = (const UnsignedInt *) (data);
+	int validData = (data != NULL) & (dataSize > 0);
+	int dataBytes = (dataSize / 4) * validData;
 
-	for (Int i=0 ; i<dataSize/4 ; i++)
+	Int i = 0;
+	for (i=0 ; i<dataBytes; i++)
 	{
 		addCRC (*uintPtr++);
 	}
 
 	int leftover = dataSize & 3;
-	if (leftover)
+	validData = (data != NULL) & (leftover > 0);
+
+	UnsignedInt val = 0;
+	const unsigned char *c = (const unsigned char *)uintPtr;
+	for (i=0; i<leftover; i++)
 	{
-		UnsignedInt val = 0;
-		const unsigned char *c = (const unsigned char *)uintPtr;
-		for (Int i=0; i<leftover; i++)
-		{
-			val += (c[i] << (i*8));
-		}
-		val = htonl(val);
-		addCRC (val);
+		val += (c[i] << (i*8));
 	}
+
+	m_crc = (m_crc << (1*validData)) + (val +((m_crc >> 31) & 0x01)) * validData;
 	
 }  // end xferImplementation
 
@@ -179,7 +162,7 @@ void XferCRC::skip( Int dataSize )
 UnsignedInt XferCRC::getCRC( void )
 {
 
-	return htonl(m_crc);
+	return htobe(m_crc);
 
 }  // end skip