diff --git a/external/sourcesdk/bitbuf.cpp b/external/sourcesdk/bitbuf.cpp
index 2b3ded6..6c7e37a 100644
--- a/external/sourcesdk/bitbuf.cpp
+++ b/external/sourcesdk/bitbuf.cpp
@@ -58,27 +58,11 @@ inline unsigned int CountTrailingZeros(unsigned int elem)
 #define FAST_BIT_SCAN 0
 #endif
 
-
-static BitBufErrorHandler g_BitBufErrorHandler = 0;
-
 inline int BitForBitnum(int bitnum)
 {
 	return GetBitForBitnum(bitnum);
 }
 
-void InternalBitBufErrorHandler( BitBufErrorType errorType, const char *pDebugName )
-{
-	if ( g_BitBufErrorHandler )
-		g_BitBufErrorHandler( errorType, pDebugName );
-}
-
-
-void SetBitBufErrorHandler( BitBufErrorHandler fn )
-{
-	g_BitBufErrorHandler = fn;
-}
-
-
 // #define BB_PROFILING
 
 unsigned long g_LittleBits[32];
@@ -130,6 +114,7 @@ bf_write::bf_write()
 	m_bOverflow = false;
 	m_bAssertOnOverflow = true;
 	m_pDebugName = NULL;
+	m_errorHandler = NULL;
 }
 
 bf_write::bf_write( const char *pDebugName, void *pData, int nBytes, int nBits )
@@ -196,6 +181,19 @@ void bf_write::SetDebugName( const char *pDebugName )
 	m_pDebugName = pDebugName;
 }
 
+void bf_write::SetErrorHandler(IBitBufOverErrorHandler* handler)
+{
+	m_errorHandler = handler;
+}
+
+bool bf_write::CallErrorHandler(BitBufErrorType errorType)
+{
+	if (m_errorHandler)
+	{
+		return m_errorHandler->HandleError(errorType, GetDebugName());
+	}
+	return false;
+}
 
 void bf_write::SeekToBit( int bitPos )
 {
@@ -452,11 +450,14 @@ bool bf_write::WriteBits(const void *pInData, int nBits)
 	int nBitsLeft = nBits;
 
 	// Bounds checking..
-	if ( (m_iCurBit+nBits) > m_nDataBits )
+	if (GetNumBitsLeft() < nBits)
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return false;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (GetNumBitsLeft() < nBits)))
+		{
+			SetOverflowFlag();
+			return false;
+		}
 	}
 
 	// Align output to dword boundary
@@ -794,6 +795,7 @@ bf_read::bf_read()
 	m_bOverflow = false;
 	m_bAssertOnOverflow = true;
 	m_pDebugName = NULL;
+	m_errorHandler = NULL;
 }
 
 bf_read::bf_read( const void *pData, int nBytes, int nBits )
@@ -847,6 +849,20 @@ void bf_read::SetDebugName( const char *pName )
 	m_pDebugName = pName;
 }
 
+void bf_read::SetErrorHandler(IBitBufOverErrorHandler* handler)
+{
+	m_errorHandler = handler;
+}
+
+bool bf_read::CallErrorHandler(BitBufErrorType errorType)
+{
+	if (m_errorHandler)
+	{
+		return m_errorHandler->HandleError(errorType, GetDebugName());
+	}
+	return false;
+}
+
 void bf_read::SetOverflowFlag()
 {
 	if ( m_bAssertOnOverflow )
diff --git a/external/sourcesdk/include/sourcesdk/bitbuf.h b/external/sourcesdk/include/sourcesdk/bitbuf.h
index 5cce666..98e6642 100644
--- a/external/sourcesdk/include/sourcesdk/bitbuf.h
+++ b/external/sourcesdk/include/sourcesdk/bitbuf.h
@@ -36,21 +36,11 @@ typedef enum
 	BITBUFERROR_NUM_ERRORS
 } BitBufErrorType;
 
-
-typedef void (*BitBufErrorHandler)( BitBufErrorType errorType, const char *pDebugName );
-
-
-#if defined( _DEBUG )
-	extern void InternalBitBufErrorHandler( BitBufErrorType errorType, const char *pDebugName );
-	#define CallErrorHandler( errorType, pDebugName ) InternalBitBufErrorHandler( errorType, pDebugName );
-#else
-	#define CallErrorHandler( errorType, pDebugName )
-#endif
-
-
-// Use this to install the error handler. Call with NULL to uninstall your error handler.
-void SetBitBufErrorHandler( BitBufErrorHandler fn );
-
+class IBitBufOverErrorHandler
+{
+public:
+	virtual bool HandleError(BitBufErrorType errorType, const char *pDebugName) = 0;
+};
 
 //-----------------------------------------------------------------------------
 // Helpers.
@@ -150,6 +140,8 @@ public:
 	const char*		GetDebugName();
 	void			SetDebugName( const char *pDebugName );
 
+	void			SetErrorHandler(IBitBufOverErrorHandler* handler);
+	bool			CallErrorHandler(BitBufErrorType errorType);
 
 // Seek to a specific position.
 public:
@@ -253,6 +245,7 @@ private:
 
 	bool			m_bAssertOnOverflow;
 	const char		*m_pDebugName;
+	IBitBufOverErrorHandler* m_errorHandler;
 };
 
 
@@ -298,10 +291,13 @@ inline const unsigned char* bf_write::GetData()	const
 
 inline bool bf_write::CheckForOverflow(int nBits)
 {
-	if ( m_iCurBit + nBits > m_nDataBits )
+	if (GetNumBitsLeft() < nBits)
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && GetNumBitsLeft() < nBits))
+		{
+			SetOverflowFlag();
+		}
 	}
 	
 	return m_bOverflow;
@@ -340,9 +336,12 @@ inline void bf_write::WriteOneBit(int nValue)
 {
 	if( m_iCurBit >= m_nDataBits )
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (m_iCurBit >= m_nDataBits)))
+		{
+			SetOverflowFlag();
+			return;
+		}
 	}
 	WriteOneBitNoCheck( nValue );
 }
@@ -352,9 +351,12 @@ inline void	bf_write::WriteOneBitAt( int iBit, int nValue )
 {
 	if( iBit >= m_nDataBits )
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (iBit >= m_nDataBits)))
+		{
+			SetOverflowFlag();
+			return;
+		}
 	}
 
 #if __i386__
@@ -379,7 +381,7 @@ inline void bf_write::WriteUBitLong( unsigned int curData, int numbits, bool bCh
 	{
 		if ( curData >= (unsigned long)(1 << numbits) )
 		{
-			CallErrorHandler( BITBUFERROR_VALUE_OUT_OF_RANGE, GetDebugName() );
+			CallErrorHandler(BITBUFERROR_VALUE_OUT_OF_RANGE);
 		}
 	}
 	Assert( numbits >= 0 && numbits <= 32 );
@@ -387,10 +389,12 @@ inline void bf_write::WriteUBitLong( unsigned int curData, int numbits, bool bCh
 
 	if ( GetNumBitsLeft() < numbits )
 	{
-		m_iCurBit = m_nDataBits;
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (GetNumBitsLeft() < numbits)))
+		{
+			SetOverflowFlag();
+			return;
+		}
 	}
 
 	int iCurBitMasked = m_iCurBit & 31;
@@ -504,6 +508,9 @@ public:
 	const char*		GetDebugName() const { return m_pDebugName; }
 	void			SetDebugName( const char *pName );
 
+	void			SetErrorHandler(IBitBufOverErrorHandler* handler);
+	bool			CallErrorHandler(BitBufErrorType errorType);
+
 	void			ExciseBits( int startbit, int bitstoremove );
 
 
@@ -651,6 +658,7 @@ private:
 	bool			m_bAssertOnOverflow;
 
 	const char		*m_pDebugName;
+	IBitBufOverErrorHandler* m_errorHandler;
 };
 
 //-----------------------------------------------------------------------------
@@ -700,10 +708,13 @@ inline bool	bf_read::SeekRelative(int iBitDelta)
 
 inline bool bf_read::CheckForOverflow(int nBits)
 {
-	if( m_iCurBit + nBits > m_nDataBits )
+	if (GetNumBitsLeft() < nBits)
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (GetNumBitsLeft() < nBits)))
+		{
+			SetOverflowFlag();
+		}
 	}
 
 	return m_bOverflow;
@@ -730,9 +741,12 @@ inline int bf_read::ReadOneBit()
 {
 	if( GetNumBitsLeft() <= 0 )
 	{
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return 0;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (GetNumBitsLeft() <= 0)))
+		{
+			SetOverflowFlag();
+			return 0;
+		}
 	}
 	return ReadOneBitNoCheck();
 }
@@ -762,10 +776,12 @@ inline unsigned int bf_read::ReadUBitLong( int numbits ) __restrict
 
 	if ( GetNumBitsLeft() < numbits )
 	{
-		m_iCurBit = m_nDataBits;
-		SetOverflowFlag();
-		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
-		return 0;
+		const bool recovered = CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN);
+		if (!recovered || (recovered && (GetNumBitsLeft() < numbits)))
+		{
+			SetOverflowFlag();
+			return 0;
+		}
 	}
 
 	unsigned int iStartBit = m_iCurBit & 31u;