From 82addf11bb325d100b676d01f5a001c95d8e1dc1 Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Tue, 27 Jun 2023 17:39:25 +0300
Subject: [PATCH] engine: common: net_encode: rewrite Delta_CompareField to be
 more efficient

---
 engine/common/net_encode.c | 150 ++++++++-----------------------------
 1 file changed, 31 insertions(+), 119 deletions(-)

diff --git a/engine/common/net_encode.c b/engine/common/net_encode.c
index 3a8433de..a10084f5 100644
--- a/engine/common/net_encode.c
+++ b/engine/common/net_encode.c
@@ -941,129 +941,41 @@ assume from and to is valid
 */
 static qboolean Delta_CompareField( delta_t *pField, void *from, void *to, double timebase )
 {
-	qboolean	bSigned = ( pField->flags & DT_SIGNED ) ? true : false;
-	float	val_a, val_b;
-	int	fromF, toF;
-
-	Assert( pField != NULL );
-	Assert( from != NULL );
-	Assert( to != NULL );
+	uint8_t *from_field = (uint8_t *)from + pField->offset;
+	uint8_t *to_field = (uint8_t *)to + pField->offset;
+	uint field_type = pField->flags & ~DT_SIGNED;
+	int fromF;
+	int toF;
 
 	if( pField->bInactive )
 		return true;
 
-	fromF = toF = 0;
-
-	if( pField->flags & DT_BYTE )
-	{
-		if( pField->flags & DT_SIGNED )
-		{
-			fromF = *(int8_t *)((int8_t *)from + pField->offset );
-			toF = *(int8_t *)((int8_t *)to + pField->offset );
-		}
-		else
-		{
-			fromF = *(uint8_t *)((int8_t *)from + pField->offset );
-			toF = *(uint8_t *)((int8_t *)to + pField->offset );
-		}
-
-		fromF = Delta_ClampIntegerField( pField, fromF, bSigned, pField->bits );
-		toF = Delta_ClampIntegerField( pField, toF, bSigned, pField->bits );
-
-		if( !Q_equal(pField->multiplier, 1.0) )
-			fromF *= pField->multiplier;
-
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-			toF *= pField->multiplier;
-	}
-	else if( pField->flags & DT_SHORT )
-	{
-		if( pField->flags & DT_SIGNED )
-		{
-			fromF = *(int16_t *)((int8_t *)from + pField->offset );
-			toF = *(int16_t *)((int8_t *)to + pField->offset );
-		}
-		else
-		{
-			fromF = *(uint16_t *)((int8_t *)from + pField->offset );
-			toF = *(uint16_t *)((int8_t *)to + pField->offset );
-		}
-
-		fromF = Delta_ClampIntegerField( pField, fromF, bSigned, pField->bits );
-		toF = Delta_ClampIntegerField( pField, toF, bSigned, pField->bits );
-
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-			fromF *= pField->multiplier;
-
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-			toF *= pField->multiplier;
-	}
-	else if( pField->flags & DT_INTEGER )
-	{
-		if( pField->flags & DT_SIGNED )
-		{
-			fromF = *(int32_t *)((int8_t *)from + pField->offset );
-			toF = *(int32_t *)((int8_t *)to + pField->offset );
-		}
-		else
-		{
-			fromF = *(uint32_t *)((int8_t *)from + pField->offset );
-			toF = *(uint32_t *)((int8_t *)to + pField->offset );
-		}
-		fromF = Delta_ClampIntegerField( pField, fromF, bSigned, pField->bits );
-		toF = Delta_ClampIntegerField( pField, toF, bSigned, pField->bits );
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-			fromF *= pField->multiplier;
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-			toF *= pField->multiplier;
-	}
-	else if( pField->flags & ( DT_ANGLE|DT_FLOAT ))
-	{
-		// don't convert floats to integers
-		fromF = *((int *)((byte *)from + pField->offset ));
-		toF = *((int *)((byte *)to + pField->offset ));
-	}
-	else if( pField->flags & DT_TIMEWINDOW_8 )
-	{
-		val_a = Q_rint((*(float *)((byte *)from + pField->offset )) * 100.0 );
-		val_b = Q_rint((*(float *)((byte *)to + pField->offset )) * 100.0 );
-		val_a -= Q_rint(timebase * 100.0);
-		val_b -= Q_rint(timebase * 100.0);
-		fromF = FloatAsInt( val_a );
-		toF = FloatAsInt( val_b );
-	}
-	else if( pField->flags & DT_TIMEWINDOW_BIG )
-	{
-		val_a = (*(float *)((byte *)from + pField->offset ));
-		val_b = (*(float *)((byte *)to + pField->offset ));
-
-		if( !Q_equal( pField->multiplier, 1.0 ) )
-		{
-			val_a *= pField->multiplier;
-			val_b *= pField->multiplier;
-			val_a = (timebase * pField->multiplier) - val_a;
-			val_b = (timebase * pField->multiplier) - val_b;
-		}
-		else
-		{
-			val_a = timebase - val_a;
-			val_b = timebase - val_b;
-		}
-
-		fromF = FloatAsInt( val_a );
-		toF = FloatAsInt( val_b );
-	}
-	else if( pField->flags & DT_STRING )
-	{
-		// compare strings
-		char	*s1 = (char *)((byte *)from + pField->offset );
-		char	*s2 = (char *)((byte *)to + pField->offset );
-
-		// 0 is equal, otherwise not equal
-		toF = Q_strcmp( s1, s2 );
-	}
-
-	return ( fromF == toF ) ? true : false;
+	switch( field_type )
+	{
+	case DT_BYTE:
+		return *to_field == *from_field;
+	case DT_SHORT:
+		return *(uint16_t *)to_field == *(uint16_t *)from_field;
+	case DT_INTEGER:
+	case DT_ANGLE:
+	case DT_FLOAT:
+		return *(uint32_t *)to_field == *(uint32_t *)from_field;
+	case DT_TIMEWINDOW_8:
+		fromF = (int)((*(float *)from_field) * 100.0f );
+		toF   = (int)((*(float *)to_field) * 100.0f );
+		return toF == fromF;
+	case DT_TIMEWINDOW_BIG:
+		fromF = (int)((*(float *)from_field) * pField->multiplier );
+		toF   = (int)((*(float *)to_field) * pField->multiplier );
+		return toF == fromF;
+	case DT_STRING:
+		return Q_strcmp( to_field, from_field ) == 0;
+	default:
+		break;
+	}
+
+	Con_Reportf( S_ERROR "bad field %s type: %d\n", pField->name, pField->flags );
+	return false;
 }
 
 /*