//========= Copyright © 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//
//===========================================================================//

// NOTE: old_bf_read is guaranteed to return zeros if it overflows.

#ifndef BITBUF_H
#define BITBUF_H

#ifdef _WIN32
#pragma once
#endif


#include "mathlib/mathlib.h"
#include "mathlib/vector.h"
#include "basetypes.h"
#include "tier0/dbg.h"




//-----------------------------------------------------------------------------
// Forward declarations.
//-----------------------------------------------------------------------------

class Vector;
class QAngle;

//-----------------------------------------------------------------------------
// You can define a handler function that will be called in case of 
// out-of-range values and overruns here.
//
// NOTE: the handler is only called in debug mode.
//
// Call SetBitBufErrorHandler to install a handler.
//-----------------------------------------------------------------------------

typedef enum
{
	BITBUFERROR_VALUE_OUT_OF_RANGE=0,		// Tried to write a value with too few bits.
	BITBUFERROR_BUFFER_OVERRUN,				// Was about to overrun a buffer.

	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 );


//-----------------------------------------------------------------------------
// Helpers.
//-----------------------------------------------------------------------------

inline int BitByte( int bits )
{
	// return PAD_NUMBER( bits, 8 ) >> 3;
	return (bits + 7) >> 3;
}

//-----------------------------------------------------------------------------
enum EBitCoordType
{
	kCW_None,
	kCW_LowPrecision,
	kCW_Integral
};

//-----------------------------------------------------------------------------
// Used for serialization
//-----------------------------------------------------------------------------

class bf_write
{
public:
	bf_write();
					
					// nMaxBits can be used as the number of bits in the buffer. 
					// It must be <= nBytes*8. If you leave it at -1, then it's set to nBytes * 8.
	bf_write( void *pData, int nBytes, int nMaxBits = -1 );
	bf_write( const char *pDebugName, void *pData, int nBytes, int nMaxBits = -1 );

	// Start writing to the specified buffer.
	// nMaxBits can be used as the number of bits in the buffer. 
	// It must be <= nBytes*8. If you leave it at -1, then it's set to nBytes * 8.
	void			StartWriting( void *pData, int nBytes, int iStartBit = 0, int nMaxBits = -1 );

	// Restart buffer writing.
	void			Reset();

	// Get the base pointer.
	unsigned char*	GetBasePointer() { return m_pData; }

	// Enable or disable assertion on overflow. 99% of the time, it's a bug that we need to catch,
	// but there may be the occasional buffer that is allowed to overflow gracefully.
	void			SetAssertOnOverflow( bool bAssert );

	// This can be set to assign a name that gets output if the buffer overflows.
	const char*		GetDebugName();
	void			SetDebugName( const char *pDebugName );


// Seek to a specific position.
public:
	
	void			SeekToBit( int bitPos );


// Bit functions.
public:

	void			WriteOneBit(int nValue);
	void			WriteOneBitNoCheck(int nValue);
	void			WriteOneBitAt( int iBit, int nValue );
	
	// Write signed or unsigned. Range is only checked in debug.
	void			WriteUBitLong( unsigned int data, int numbits, bool bCheckRange=true );
	void			WriteSBitLong( int data, int numbits );
	
	// Tell it whether or not the data is unsigned. If it's signed,
	// cast to unsigned before passing in (it will cast back inside).
	void			WriteBitLong(unsigned int data, int numbits, bool bSigned);

	// Write a list of bits in.
	bool			WriteBits(const void *pIn, int nBits);

	// writes an unsigned integer with variable bit length
	void			WriteUBitVar( unsigned int data );

	// Copy the bits straight out of pIn. This seeks pIn forward by nBits.
	// Returns an error if this buffer or the read buffer overflows.
	bool			WriteBitsFromBuffer( class bf_read *pIn, int nBits );
	
	void			WriteBitAngle( float fAngle, int numbits );
	void			WriteBitCoord (const float f);
	void			WriteBitCoordMP( const float f, EBitCoordType coordType );
	void 			WriteBitCellCoord( const float f, int bits, EBitCoordType coordType );
	void			WriteBitFloat(float val);
	void			WriteBitVec3Coord( const Vector& fa );
	void			WriteBitNormal( float f );
	void			WriteBitVec3Normal( const Vector& fa );
	void			WriteBitAngles( const QAngle& fa );


// Byte functions.
public:

	void			WriteChar(int val);
	void			WriteByte( unsigned int val );
	void			WriteShort(int val);
	void			WriteWord( unsigned int val );
	void			WriteLong(long val);
	void			WriteLongLong(int64 val);
	void			WriteFloat(float val);
	bool			WriteBytes( const void *pBuf, int nBytes );

	// Returns false if it overflows the buffer.
	bool			WriteString(const char *pStr);
	bool			WriteString(const wchar_t *pStr);


// Status.
public:

	// How many bytes are filled in?
	int				GetNumBytesWritten();
	int				GetNumBitsWritten();
	int				GetMaxNumBits();
	int				GetNumBitsLeft();
	int				GetNumBytesLeft();
	unsigned char*	GetData();

	// Has the buffer overflowed?
	bool			CheckForOverflow(int nBits);
	inline bool		IsOverflowed() const {return m_bOverflow;}

	inline void		SetOverflowFlag();


public:
	// The current buffer.
	unsigned char*	m_pData;
	int				m_nDataBytes;
	int				m_nDataBits;
	
	// Where we are in the buffer.
	int				m_iCurBit;
	
private:

	// Errors?
	bool			m_bOverflow;

	bool			m_bAssertOnOverflow;
	const char		*m_pDebugName;
};


//-----------------------------------------------------------------------------
// Inlined methods
//-----------------------------------------------------------------------------

// How many bytes are filled in?
inline int bf_write::GetNumBytesWritten()	
{
	return BitByte(m_iCurBit);
}

inline int bf_write::GetNumBitsWritten()	
{
	return m_iCurBit;
}

inline int bf_write::GetMaxNumBits()		
{
	return m_nDataBits;
}

inline int bf_write::GetNumBitsLeft()	
{
	return m_nDataBits - m_iCurBit;
}

inline int bf_write::GetNumBytesLeft()	
{
	return GetNumBitsLeft() >> 3;
}

inline unsigned char* bf_write::GetData()			
{
	return m_pData;
}

inline bool bf_write::CheckForOverflow(int nBits)
{
	if ( m_iCurBit + nBits > m_nDataBits )
	{
		SetOverflowFlag();
		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
	}
	
	return m_bOverflow;
}

inline void bf_write::SetOverflowFlag()
{
	if ( m_bAssertOnOverflow )
	{
		Assert( false );
	}

	m_bOverflow = true;
}

inline void bf_write::WriteOneBitNoCheck(int nValue)
{
	if(nValue)
		m_pData[m_iCurBit >> 3] |= (1 << (m_iCurBit & 7));
	else
		m_pData[m_iCurBit >> 3] &= ~(1 << (m_iCurBit & 7));

	++m_iCurBit;
}

inline void bf_write::WriteOneBit(int nValue)
{
	if( !CheckForOverflow(1) )
		WriteOneBitNoCheck( nValue );
}


inline void	bf_write::WriteOneBitAt( int iBit, int nValue )
{
	if( iBit+1 > m_nDataBits )
	{
		SetOverflowFlag();
		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
		return;
	}

	if( nValue )
		m_pData[iBit >> 3] |= (1 << (iBit & 7));
	else
		m_pData[iBit >> 3] &= ~(1 << (iBit & 7));
}


inline void bf_write::WriteUBitLong( unsigned int curData, int numbits, bool bCheckRange )
{
#ifdef _DEBUG
	// Make sure it doesn't overflow.
	if ( bCheckRange && numbits < 32 )
	{
		if ( curData >= (unsigned long)(1 << numbits) )
		{
			CallErrorHandler( BITBUFERROR_VALUE_OUT_OF_RANGE, GetDebugName() );
		}
	}
	Assert( numbits >= 0 && numbits <= 32 );
#endif

	extern unsigned long g_BitWriteMasks[32][33];

	// Bounds checking..
	if ((m_iCurBit+numbits) > m_nDataBits)
	{
		m_iCurBit = m_nDataBits;
		SetOverflowFlag();
		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
		return;
	}

	int nBitsLeft = numbits;
	int iCurBit = m_iCurBit;

	// Mask in a dword.
	unsigned int iDWord = iCurBit >> 5;
	Assert( (iDWord*4 + sizeof(long)) <= (unsigned int)m_nDataBytes );

	unsigned long iCurBitMasked = iCurBit & 31;

	uint32 dword = LoadLittleDWord( (uint32*)m_pData, iDWord );

	dword &= g_BitWriteMasks[iCurBitMasked][nBitsLeft];
	dword |= curData << iCurBitMasked;

	// write to stream (lsb to msb ) properly
	StoreLittleDWord( (uint32*)m_pData, iDWord, dword );

	// Did it span a dword?
	int nBitsWritten = 32 - iCurBitMasked;
	if ( nBitsWritten < nBitsLeft )
	{
		nBitsLeft -= nBitsWritten;
		curData >>= nBitsWritten;

		// read from stream (lsb to msb) properly 
		dword = LoadLittleDWord( (uint32*)m_pData, iDWord+1 );

		dword &= g_BitWriteMasks[0][nBitsLeft];
		dword |= curData;

		// write to stream (lsb to msb) properly 
		StoreLittleDWord( (uint32*)m_pData, iDWord+1, dword );
	}

	m_iCurBit += numbits;
}


//-----------------------------------------------------------------------------
// This is useful if you just want a buffer to write into on the stack.
//-----------------------------------------------------------------------------

template<int SIZE>
class old_bf_write_static : public bf_write
{
public:
	inline old_bf_write_static() : bf_write(m_StaticData, SIZE) {}

	char	m_StaticData[SIZE];
};



//-----------------------------------------------------------------------------
// Used for unserialization
//-----------------------------------------------------------------------------

class old_bf_read
{
public:
	old_bf_read();

	// nMaxBits can be used as the number of bits in the buffer. 
	// It must be <= nBytes*8. If you leave it at -1, then it's set to nBytes * 8.
	old_bf_read( const void *pData, int nBytes, int nBits = -1 );
	old_bf_read( const char *pDebugName, const void *pData, int nBytes, int nBits = -1 );

	// Start reading from the specified buffer.
	// pData's start address must be dword-aligned.
	// nMaxBits can be used as the number of bits in the buffer. 
	// It must be <= nBytes*8. If you leave it at -1, then it's set to nBytes * 8.
	void			StartReading( const void *pData, int nBytes, int iStartBit = 0, int nBits = -1 );

	// Restart buffer reading.
	void			Reset();

	// Enable or disable assertion on overflow. 99% of the time, it's a bug that we need to catch,
	// but there may be the occasional buffer that is allowed to overflow gracefully.
	void			SetAssertOnOverflow( bool bAssert );

	// This can be set to assign a name that gets output if the buffer overflows.
	const char*		GetDebugName();
	void			SetDebugName( const char *pName );

	void			ExciseBits( int startbit, int bitstoremove );


// Bit functions.
public:
	
	// Returns 0 or 1.
	int				ReadOneBit();


protected:

	unsigned int	CheckReadUBitLong(int numbits);		// For debugging.
	int				ReadOneBitNoCheck();				// Faster version, doesn't check bounds and is inlined.
	bool			CheckForOverflow(int nBits);


public:

	// Get the base pointer.
	const unsigned char*	GetBasePointer() { return m_pData; }

	FORCEINLINE int TotalBytesAvailable( void ) const
	{
		return m_nDataBytes;
	}

	// Read a list of bits in..
	void            ReadBits(void *pOut, int nBits);
	
	float			ReadBitAngle( int numbits );

	unsigned int	ReadUBitLong( int numbits );
	unsigned int	PeekUBitLong( int numbits );
	int				ReadSBitLong( int numbits );

	// reads an unsigned integer with variable bit length
	unsigned int	ReadUBitVar();
	
	// You can read signed or unsigned data with this, just cast to 
	// a signed int if necessary.
	unsigned int	ReadBitLong(int numbits, bool bSigned);
	
	float			ReadBitCoord();
	float			ReadBitCoordMP( EBitCoordType coordType );
	float 			ReadBitCellCoord( int bits, EBitCoordType coordType );
	float			ReadBitFloat();
	float			ReadBitNormal();
	void			ReadBitVec3Coord( Vector& fa );
	void			ReadBitVec3Normal( Vector& fa );
	void			ReadBitAngles( QAngle& fa );


// Byte functions (these still read data in bit-by-bit).
public:
	
	int				ReadChar();
	int				ReadByte();
	int				ReadShort();
	int				ReadWord();
	long			ReadLong();
	int64			ReadLongLong();
	float			ReadFloat();
	bool			ReadBytes(void *pOut, int nBytes);

	// Returns false if bufLen isn't large enough to hold the
	// string in the buffer.
	//
	// Always reads to the end of the string (so you can read the
	// next piece of data waiting).
	//
	// If bLine is true, it stops when it reaches a '\n' or a null-terminator.
	//
	// pStr is always null-terminated (unless bufLen is 0).
	//
	// pOutNumChars is set to the number of characters left in pStr when the routine is 
	// complete (this will never exceed bufLen-1).
	//
	bool			ReadString( char *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL );
	bool			ReadWString( wchar_t *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL );

	// Reads a string and allocates memory for it. If the string in the buffer
	// is > 2048 bytes, then pOverflow is set to true (if it's not NULL).
	char*			ReadAndAllocateString( bool *pOverflow = 0 );

// Status.
public:
	int				GetNumBytesLeft();
	int				GetNumBytesRead();
	int				GetNumBitsLeft();
	int				GetNumBitsRead() const;

	// Has the buffer overflowed?
	inline bool		IsOverflowed() const {return m_bOverflow;}

	inline bool		Seek(int iBit);					// Seek to a specific bit.
	inline bool		SeekRelative(int iBitDelta);	// Seek to an offset from the current position.

	// Called when the buffer is overflowed.
	inline void		SetOverflowFlag();


public:

	// The current buffer.
	const unsigned char*	m_pData;
	int						m_nDataBytes;
	int						m_nDataBits;
	
	// Where we are in the buffer.
	int				m_iCurBit;


private:	
	// used by varbit reads internally
	inline int CountRunOfZeros();

	// Errors?
	bool			m_bOverflow;

	// For debugging..
	bool			m_bAssertOnOverflow;

	const char		*m_pDebugName;
};

//-----------------------------------------------------------------------------
// Inlines.
//-----------------------------------------------------------------------------

inline int old_bf_read::GetNumBytesRead()	
{
	return BitByte(m_iCurBit);
}

inline int old_bf_read::GetNumBitsLeft()	
{
	return m_nDataBits - m_iCurBit;
}

inline int old_bf_read::GetNumBytesLeft()	
{
	return GetNumBitsLeft() >> 3;
}

inline int old_bf_read::GetNumBitsRead() const
{
	return m_iCurBit;
}

inline void old_bf_read::SetOverflowFlag()
{
	if ( m_bAssertOnOverflow )
	{
		Assert( false );
	}

	m_bOverflow = true;
}

inline bool old_bf_read::Seek(int iBit)
{
	if(iBit < 0 || iBit > m_nDataBits)
	{
		SetOverflowFlag();
		m_iCurBit = m_nDataBits;
		return false;
	}
	else
	{
		m_iCurBit = iBit;
		return true;
	}
}

// Seek to an offset from the current position.
inline bool	old_bf_read::SeekRelative(int iBitDelta)		
{
	return Seek(m_iCurBit+iBitDelta);
}	

inline bool old_bf_read::CheckForOverflow(int nBits)
{
	if( m_iCurBit + nBits > m_nDataBits )
	{
		SetOverflowFlag();
		CallErrorHandler( BITBUFERROR_BUFFER_OVERRUN, GetDebugName() );
	}

	return m_bOverflow;
}

inline int old_bf_read::ReadOneBitNoCheck()
{
	int value = m_pData[m_iCurBit >> 3] & (1 << (m_iCurBit & 7));
	++m_iCurBit;
	return !!value;
}

inline int old_bf_read::ReadOneBit()
{
	return (!CheckForOverflow(1)) ?	ReadOneBitNoCheck() : 0;
}

inline float old_bf_read::ReadBitFloat()
{
	long val;

	Assert(sizeof(float) == sizeof(long));
	Assert(sizeof(float) == 4);

	if(CheckForOverflow(32))
		return 0.0f;

	int bit = m_iCurBit & 0x7;
	int byte = m_iCurBit >> 3;
	val = m_pData[byte] >> bit;
	val |= ((int)m_pData[byte + 1]) << (8 - bit);
	val |= ((int)m_pData[byte + 2]) << (16 - bit);
	val |= ((int)m_pData[byte + 3]) << (24 - bit);
	if (bit != 0)
		val |= ((int)m_pData[byte + 4]) << (32 - bit);
	m_iCurBit += 32;
	return *((float*)&val);
}


inline unsigned int old_bf_read::ReadUBitLong( int numbits )
{
	extern unsigned long g_ExtraMasks[32];

	if ( (m_iCurBit+numbits) > m_nDataBits )
	{
		m_iCurBit = m_nDataBits;
		SetOverflowFlag();
		return 0;
	}

	Assert( numbits > 0 && numbits <= 32 );

	// Read the current dword.
	int idword1 = m_iCurBit >> 5;
	unsigned int dword1 = LoadLittleDWord( (uint32*)m_pData, idword1 );

	dword1 >>= (m_iCurBit & 31); // Get the bits we're interested in.

	m_iCurBit += numbits;
	unsigned int ret = dword1;

	// Does it span this dword?
	if ( (m_iCurBit-1) >> 5 == idword1 )
	{
		if (numbits != 32)
			ret &= g_ExtraMasks[numbits];
	}
	else
	{
		int nExtraBits = m_iCurBit & 31;
		unsigned int dword2 = LoadLittleDWord( (uint32*)m_pData, idword1+1 );

		dword2 &= g_ExtraMasks[nExtraBits];

		// No need to mask since we hit the end of the dword.
		// Shift the second dword's part into the high bits.
		ret |= (dword2 << (numbits - nExtraBits));
	}

	return ret;
}


class CBitBuffer
{
public:
	char const * m_pDebugName;
	bool m_bOverflow;
	int m_nDataBits;
	size_t m_nDataBytes;

	void SetDebugName( char const *pName )
	{
		m_pDebugName = pName;
	}

	CBitBuffer( void )
	{
		m_bOverflow = false;
		m_pDebugName = NULL;
		m_nDataBits = -1;
		m_nDataBytes = 0;
	}

	FORCEINLINE void SetOverflowFlag( void )
	{
		m_bOverflow = true;
	}

	FORCEINLINE bool IsOverflowed( void ) const
	{
		return m_bOverflow;
	}

	static const uint32 s_nMaskTable[33];							// 0 1 3 7 15 ..

};

class CBitWrite : public CBitBuffer
{
	uint32 m_nOutBufWord;
	int m_nOutBitsAvail;
	uint32 *m_pDataOut;
	uint32 *m_pBufferEnd;
	uint32 *m_pData;
	bool m_bFlushed;

public:
	void StartWriting( void *pData, int nBytes, int iStartBit = 0, int nMaxBits = -1 );


	CBitWrite( void *pData, int nBytes, int nBits = -1 )
	{
		m_bFlushed = false;
		StartWriting( pData, nBytes, 0, nBits );
	}
	
	CBitWrite( const char *pDebugName, void *pData, int nBytes, int nBits = -1 )
	{
		m_bFlushed = false;
		SetDebugName( pDebugName );
		StartWriting( pData, nBytes, 0, nBits );
	}

	CBitWrite( void )
	{
		m_bFlushed = false;
	}

	~CBitWrite( void )
	{
		TempFlush();
		Assert( (! m_pData ) || m_bFlushed );
	}
	FORCEINLINE int GetNumBitsLeft( void ) const
	{
		return m_nOutBitsAvail + ( 32 * ( m_pBufferEnd - m_pDataOut -1 ) );
	}

	FORCEINLINE void Reset( void )
	{
		m_bOverflow = false;
		m_nOutBitsAvail = 32;
		m_pDataOut = m_pData;
		m_nOutBufWord = 0;
		
	}

	FORCEINLINE void TempFlush( void )
	{
		// someone wants to know how much data we have written, or the pointer to it, so we'd better make
		// sure we write our data
		if ( m_nOutBitsAvail != 32 )
		{
			if ( m_pDataOut == m_pBufferEnd )
			{
				SetOverflowFlag();
			}
			else
			{
				StoreLittleDWord( m_pDataOut, 0, LoadLittleDWord(m_pDataOut,0) & ~s_nMaskTable[ 32 - m_nOutBitsAvail ] | m_nOutBufWord );
			}
		}
		m_bFlushed = true;
	}

	FORCEINLINE unsigned char *GetBasePointer()
	{
		TempFlush();
		return reinterpret_cast< unsigned char *>( m_pData );
	}

	FORCEINLINE unsigned char *GetData()
	{
		return GetBasePointer();
	}

	FORCEINLINE void Finish();
	FORCEINLINE void Flush();
	FORCEINLINE void FlushNoCheck();
	FORCEINLINE void WriteOneBit(int nValue);
	FORCEINLINE void WriteOneBitNoCheck(int nValue);
	FORCEINLINE void WriteUBitLong( unsigned int data, int numbits, bool bCheckRange=true );
	FORCEINLINE void WriteSBitLong( int data, int numbits );
	FORCEINLINE void WriteUBitVar( unsigned int data );
	FORCEINLINE void WriteBitFloat( float flValue );
	FORCEINLINE void WriteFloat( float flValue );
	bool WriteBits(const void *pInData, int nBits);
	void WriteBytes( const void *pBuf, int nBytes );
	void SeekToBit( int nSeekPos );

	FORCEINLINE int GetNumBitsWritten( void ) const
	{
		return ( 32 - m_nOutBitsAvail ) + ( 32 * ( m_pDataOut - m_pData ) );
	}

	FORCEINLINE int GetNumBytesWritten( void ) const
	{
		return ( GetNumBitsWritten() + 7 ) >> 3;
	}


	FORCEINLINE void WriteLong(long val)
	{
		WriteSBitLong( val, 32 );
	}



	FORCEINLINE void WriteChar( int val )
	{
		WriteSBitLong(val, sizeof(char) << 3 );
	}

	FORCEINLINE void WriteByte( int val )
	{
		WriteUBitLong(val, sizeof(unsigned char) << 3, false );
	}

	FORCEINLINE void WriteShort(int val)
	{
		WriteSBitLong(val, sizeof(short) << 3);
	}

	FORCEINLINE void WriteWord(int val)
	{
		WriteUBitLong(val, sizeof(unsigned short) << 3);
	}
	
	bool WriteString( const char *pStr );
	bool WriteString( const wchar_t *pStr );

	void WriteLongLong( int64 val );

	void WriteBitAngle( float fAngle, int numbits );
	void WriteBitCoord (const float f);
	void WriteBitCoordMP( const float f, EBitCoordType coordType );
	void WriteBitCellCoord( const float f, int bits, EBitCoordType coordType );
	void WriteBitVec3Coord( const Vector& fa );
	void WriteBitNormal( float f );
	void WriteBitVec3Normal( const Vector& fa );
	void WriteBitAngles( const QAngle& fa );

	// Copy the bits straight out of pIn. This seeks pIn forward by nBits.
	// Returns an error if this buffer or the read buffer overflows.
	bool WriteBitsFromBuffer( class bf_read *pIn, int nBits );
	
};

void CBitWrite::Finish( void )
{
	if ( m_nOutBitsAvail != 32 )
	{
		if ( m_pDataOut == m_pBufferEnd )
		{
			SetOverflowFlag();
		}
		StoreLittleDWord( m_pDataOut, 0, m_nOutBufWord );
	}
}

void CBitWrite::FlushNoCheck( void )
{
	StoreLittleDWord( m_pDataOut++, 0, m_nOutBufWord );
	m_nOutBitsAvail = 32;
	m_nOutBufWord = 0;										// ugh - I need this because of 32 bit writes. a<<=32 is a nop
	
}
void CBitWrite::Flush( void )
{
	if ( m_pDataOut == m_pBufferEnd )
	{
		SetOverflowFlag();
	}
	else
	{
		StoreLittleDWord( m_pDataOut++, 0, m_nOutBufWord );
	}
	m_nOutBufWord = 0;										// ugh - I need this because of 32 bit writes. a<<=32 is a nop
	m_nOutBitsAvail = 32;
	
}
void CBitWrite::WriteOneBitNoCheck( int nValue )
{
	m_nOutBufWord |= ( nValue & 1 ) << ( 32 - m_nOutBitsAvail );
	if ( --m_nOutBitsAvail == 0 )
	{
		FlushNoCheck();
	}
}

void CBitWrite::WriteOneBit( int nValue )
{
	m_nOutBufWord |= ( nValue & 1 ) << ( 32 - m_nOutBitsAvail );
	if ( --m_nOutBitsAvail == 0 )
	{
		Flush();
	}
}

FORCEINLINE void CBitWrite::WriteUBitLong( unsigned int nData, int nNumBits, bool bCheckRange )
{

#ifdef _DEBUG
	// Make sure it doesn't overflow.
	if ( bCheckRange && nNumBits < 32 )
	{
		Assert( nData <= (unsigned long)(1 << nNumBits ) );
	}
	Assert( nNumBits >= 0 && nNumBits <= 32 );
#endif
	if ( nNumBits <= m_nOutBitsAvail )
	{
		if ( bCheckRange )
			m_nOutBufWord |= ( nData ) << ( 32 - m_nOutBitsAvail );
		else
			m_nOutBufWord |= ( nData & s_nMaskTable[ nNumBits] ) << ( 32 - m_nOutBitsAvail );
		m_nOutBitsAvail -= nNumBits;
		if ( m_nOutBitsAvail == 0 )
		{
			Flush();
		}
	}
	else
	{
		// split dwords case
		int nOverflowBits = ( nNumBits - m_nOutBitsAvail );
		m_nOutBufWord |= ( nData & s_nMaskTable[m_nOutBitsAvail] ) << ( 32 - m_nOutBitsAvail );
		Flush();
		m_nOutBufWord = ( nData >> ( nNumBits - nOverflowBits ) );
		m_nOutBitsAvail = 32 - nOverflowBits;
	}
}

FORCEINLINE void CBitWrite::WriteSBitLong( int nData, int nNumBits )
{
	WriteUBitLong( ( uint32 ) nData, nNumBits, false );
}

FORCEINLINE void CBitWrite::WriteUBitVar( unsigned int n )
{
	if ( n < 16 )
		WriteUBitLong( n, 6 );
	else
		if ( n < 256 )
			WriteUBitLong( ( n & 15 ) | 16 | ( ( n & ( 128 | 64 | 32 | 16 ) ) << 2 ), 10 );
		else
			if ( n < 4096 )
				WriteUBitLong( ( n & 15 ) | 32 | ( ( n & ( 2048 | 1024 | 512 | 256 | 128 | 64 | 32 | 16 ) ) << 2 ), 14 );
			else
			{
				WriteUBitLong( ( n & 15 ) | 48, 6 );
				WriteUBitLong( ( n >> 4 ), 32 - 4 );
			}
}

FORCEINLINE void CBitWrite::WriteBitFloat( float flValue )
{
	WriteUBitLong( *((uint32 *) &flValue ), 32 );
}

FORCEINLINE void CBitWrite::WriteFloat( float flValue )
{
	// Pre-swap the float, since WriteBits writes raw data
	LittleFloat( &flValue, &flValue );
	WriteUBitLong( *((uint32 *) &flValue ), 32 );
}

class CBitRead : public CBitBuffer
{
	uint32 m_nInBufWord;
	int m_nBitsAvail;
	uint32 const *m_pDataIn;
	uint32 const *m_pBufferEnd;
	uint32 const *m_pData;

public:
	CBitRead( const void *pData, int nBytes, int nBits = -1 )
	{
		StartReading( pData, nBytes, 0, nBits );
	}
	
	CBitRead( const char *pDebugName, const void *pData, int nBytes, int nBits = -1 )
	{
		SetDebugName( pDebugName );
		StartReading( pData, nBytes, 0, nBits );
	}

	CBitRead( void ) : CBitBuffer()
	{
	}

	FORCEINLINE int Tell( void ) const
	{
		return GetNumBitsRead();
	}
	
	FORCEINLINE size_t TotalBytesAvailable( void ) const
	{
		return m_nDataBytes;
	}

	FORCEINLINE int GetNumBitsLeft() const 
	{
		return m_nDataBits - Tell();
	}

	FORCEINLINE int GetNumBytesLeft() const
	{
		return GetNumBitsLeft() >> 3;
	}

	bool Seek( int nPosition );

	FORCEINLINE bool SeekRelative( int nOffset )
	{
		return Seek( GetNumBitsRead() + nOffset );
	}

	FORCEINLINE unsigned char const * GetBasePointer()
	{
		return reinterpret_cast< unsigned char const *>( m_pData );
	}

	void StartReading( const void *pData, int nBytes, int iStartBit = 0, int nBits = -1 );

	FORCEINLINE int GetNumBitsRead( void ) const;

	FORCEINLINE void GrabNextDWord( bool bOverFlowImmediately = false );
	FORCEINLINE void FetchNext( void );
	FORCEINLINE unsigned int ReadUBitLong( int numbits );
	FORCEINLINE int ReadSBitLong( int numbits );
	FORCEINLINE unsigned int ReadUBitVar( void );
	FORCEINLINE unsigned int PeekUBitLong( int numbits );
	FORCEINLINE float ReadBitFloat( void );
	float ReadBitCoord();
	float ReadBitCoordMP( EBitCoordType coordType );
	float ReadBitCellCoord( int bits, EBitCoordType coordType );
	float ReadBitNormal();
	void ReadBitVec3Coord( Vector& fa );
	void ReadBitVec3Normal( Vector& fa );
	void ReadBitAngles( QAngle& fa );
	bool ReadBytes(void *pOut, int nBytes);
	float ReadBitAngle( int numbits );

	// Returns 0 or 1.
	FORCEINLINE int	ReadOneBit( void );
	FORCEINLINE int ReadLong( void );
	FORCEINLINE int ReadChar( void );
	FORCEINLINE int ReadByte( void );
	FORCEINLINE int ReadShort( void );
	FORCEINLINE int ReadWord( void );
	FORCEINLINE float ReadFloat( void );
	void ReadBits(void *pOut, int nBits);

	// Returns false if bufLen isn't large enough to hold the
	// string in the buffer.
	//
	// Always reads to the end of the string (so you can read the
	// next piece of data waiting).
	//
	// If bLine is true, it stops when it reaches a '\n' or a null-terminator.
	//
	// pStr is always null-terminated (unless bufLen is 0).
	//
	// pOutN<umChars is set to the number of characters left in pStr when the routine is 
	// complete (this will never exceed bufLen-1).
	//
	bool ReadString( char *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL );
	bool ReadWString( wchar_t *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL );
	char* ReadAndAllocateString( bool *pOverflow = 0 );

	int64 ReadLongLong( void );

};


FORCEINLINE int CBitRead::GetNumBitsRead( void ) const
{
	if ( ! m_pData )									   // pesky null ptr bitbufs. these happen.
		return 0;
	int nCurOfs = ( 32 - m_nBitsAvail ) + ( 8 * sizeof( m_pData[0] ) * ( m_pDataIn - m_pData -1  ) );
	int nAdjust = 8 * ( m_nDataBytes & 3 );
	return MIN( nCurOfs + nAdjust, m_nDataBits );

}

FORCEINLINE void CBitRead::GrabNextDWord( bool bOverFlowImmediately )
{
	if ( m_pDataIn == m_pBufferEnd )
	{
		m_nBitsAvail = 1;									// so that next read will run out of words
		m_nInBufWord = 0;
		m_pDataIn++;										// so seek count increments like old
		if ( bOverFlowImmediately )
			SetOverflowFlag();
	}
	else
		if ( m_pDataIn > m_pBufferEnd )
		{
			SetOverflowFlag();
			m_nInBufWord = 0;
		}
		else
		{
			Assert( reinterpret_cast<int>(m_pDataIn) + 3 < reinterpret_cast<int>(m_pBufferEnd));
			m_nInBufWord = LittleDWord( *( m_pDataIn++ ) );
		}
}

FORCEINLINE void CBitRead::FetchNext( void )
{
	m_nBitsAvail = 32;
	GrabNextDWord( false );
}

int CBitRead::ReadOneBit( void )
{
	int nRet = m_nInBufWord & 1;
	if ( --m_nBitsAvail == 0 )
	{
		FetchNext();
	}
	else
		m_nInBufWord >>= 1;
	return nRet;
}


unsigned int CBitRead::ReadUBitLong( int numbits )
{
	if ( m_nBitsAvail >= numbits )
	{
		unsigned int nRet = m_nInBufWord & s_nMaskTable[ numbits ];
		m_nBitsAvail -= numbits;
		if ( m_nBitsAvail )
		{
			m_nInBufWord >>= numbits;
		}
		else
		{
			FetchNext();
		}
		return nRet;
	}
	else
	{
		// need to merge words
		unsigned int nRet = m_nInBufWord;
		numbits -= m_nBitsAvail;
		GrabNextDWord( true );
		if ( m_bOverflow )
			return 0;
		nRet |= ( ( m_nInBufWord & s_nMaskTable[numbits] ) << m_nBitsAvail );
		m_nBitsAvail = 32 - numbits;
		m_nInBufWord >>= numbits;
		return nRet;
	}
}

FORCEINLINE unsigned int CBitRead::PeekUBitLong( int numbits )
{
	int nSaveBA = m_nBitsAvail;
	int nSaveW = m_nInBufWord;
	uint32 const *pSaveP = m_pDataIn;
	unsigned int nRet = ReadUBitLong( numbits );
	m_nBitsAvail = nSaveBA;
	m_nInBufWord = nSaveW;
	m_pDataIn = pSaveP;
	return nRet;
}

FORCEINLINE int CBitRead::ReadSBitLong( int numbits )
{
	int nRet = ReadUBitLong( numbits );
	// sign extend
	return ( nRet << ( 32 - numbits ) ) >> ( 32 - numbits );
}

FORCEINLINE int CBitRead::ReadLong( void )
{
	return ( int ) ReadUBitLong( sizeof(long) << 3 );
}

FORCEINLINE float CBitRead::ReadFloat( void )
{
	uint32 nUval = ReadUBitLong( sizeof(long) << 3 );
	return * ( ( float * ) &nUval );
}

#ifdef _WIN32
#pragma warning(push)
#pragma warning(disable : 4715)								// disable warning on not all cases
															// returning a value. throwing default:
															// in measurably reduces perf in bit
															// packing benchmark
#endif
FORCEINLINE unsigned int CBitRead::ReadUBitVar( void )
{
	unsigned int ret = ReadUBitLong( 6 );
	switch( ret & ( 16 | 32 ) )
	{
		case 16:
			ret = ( ret & 15 ) | ( ReadUBitLong( 4 ) << 4 );
			Assert( ret >= 16);
			break;
				
		case 32:
			ret = ( ret & 15 ) | ( ReadUBitLong( 8 ) << 4 );
			Assert( ret >= 256);
			break;
		case 48:
			ret = ( ret & 15 ) | ( ReadUBitLong( 32 - 4 ) << 4 );
			Assert( ret >= 4096 );
			break;
	}
	return ret;
}
#ifdef _WIN32
#pragma warning(pop)
#endif

FORCEINLINE float CBitRead::ReadBitFloat( void )
{
	uint32 nvalue = ReadUBitLong( 32 );
	return *( ( float * ) &nvalue );
}

int CBitRead::ReadChar( void )
{
	return ReadSBitLong(sizeof(char) << 3);
}

int CBitRead::ReadByte( void )
{
	return ReadUBitLong(sizeof(unsigned char) << 3);
}

int CBitRead::ReadShort( void )
{
	return ReadSBitLong(sizeof(short) << 3);
}

int CBitRead::ReadWord( void )
{
	return ReadUBitLong(sizeof(unsigned short) << 3);
}

#define WRAP_READ( bc ) 																									  \
class bf_read : public bc																									  \
{																															  \
public:																														  \
    FORCEINLINE bf_read( void ) : bc(  )																								  \
	{																														  \
	}																														  \
																															  \
	FORCEINLINE bf_read( const void *pData, int nBytes, int nBits = -1 ) : bc( pData, nBytes, nBits )									  \
	{																														  \
	}																														  \
																															  \
	FORCEINLINE bf_read( const char *pDebugName, const void *pData, int nBytes, int nBits = -1 ) : bc( pDebugName, pData, nBytes, nBits ) \
	{																														  \
	}																														  \
};

#if 0


#define DELEGATE0( t, m )	t m()					\
{												\
		Check(); \
	t nOld = old1.m();						\
	t nNew = new1.m();						\
	Assert( nOld == nNew );						\
	Check();									\
	return nOld;								\
}
#define DELEGATE1( t, m, t1 )	t m( t1 x)					\
{												\
		Check(); \
	t nOld = old1.m( x);						\
	t nNew = new1.m( x );						\
	Assert( nOld == nNew );						\
	Check();									\
	return nOld;								\
}

#define DELEGATE0I( m )	DELEGATE0( int, m )
#define DELEGATE0LL( m ) DELEGATE0( int64, m )

class bf_read
{
	old_bf_read old1;
	CBitRead new1;

	void Check( void ) const
	{
		int n=new1.GetNumBitsRead();
		int o=old1.GetNumBitsRead();
		Assert( n == o );
		Assert( old1.IsOverflowed() == new1.IsOverflowed() );
	}

public:
    FORCEINLINE bf_read( void ) : old1(), new1()
	{
	}

	FORCEINLINE bf_read( const void *pData, int nBytes, int nBits = -1 ) : old1( pData, nBytes, nBits ),new1( pData, nBytes, nBits )
	{
	}

	FORCEINLINE bf_read( const char *pDebugName, const void *pData, int nBytes, int nBits = -1 ) : old1( pDebugName, pData, nBytes, nBits ), new1( pDebugName, pData, nBytes, nBits )
	{
	}

	FORCEINLINE bool IsOverflowed( void ) const
	{
		bool bOld = old1.IsOverflowed();
		bool bNew = new1.IsOverflowed();
		Assert( bOld == bNew );
		Check();
		return bOld;

	}

	void ReadBits(void *pOut, int nBits)
	{
		old1.ReadBits( pOut, nBits );
		void *mem=stackalloc( 1+ ( nBits / 8 ) );
		new1.ReadBits( mem, nBits );
		Assert( memcmp( mem, pOut, nBits / 8 ) == 0 );
	}

	bool ReadBytes(void *pOut, int nBytes)
	{
		ReadBits(pOut, nBytes << 3);
		return ! IsOverflowed();
	}


	unsigned int ReadUBitLong( int numbits )
	{
		unsigned int nOld = old1.ReadUBitLong( numbits );
		unsigned int nNew = new1.ReadUBitLong( numbits );
		Assert( nOld == nNew );
		Check();
		return nOld;
	}

	unsigned const char*	GetBasePointer()
	{
		Assert( old1.GetBasePointer() == new1.GetBasePointer() );
		Check();
		return old1.GetBasePointer();
	}
	void SetDebugName( const char *pDebugName )
	{
		old1.SetDebugName( pDebugName );
		new1.SetDebugName( pDebugName );
		Check();
	}

	void StartReading( const void *pData, int nBytes, int iStartBit = 0, int nBits = -1 )
	{
		old1.StartReading( pData, nBytes, iStartBit, nBits );
		new1.StartReading( pData, nBytes, iStartBit, nBits );
		Check();
	}

	void SetAssertOnOverflow( bool bAssert )
	{
		old1.SetAssertOnOverflow( bAssert );
//		new1.SetAssertOnOverflow( bAssert );
		Check();
	}

	DELEGATE0I( ReadOneBit );
	DELEGATE0I( ReadByte );
	DELEGATE0I( ReadWord );
	DELEGATE0I( ReadLong );
	DELEGATE0I( GetNumBytesLeft );
	DELEGATE0I( ReadShort );
	DELEGATE1( int, PeekUBitLong, int );
	DELEGATE0I( ReadChar );
	DELEGATE0I( GetNumBitsRead );
	DELEGATE0LL( ReadLongLong );
	DELEGATE0( float, ReadFloat);
	DELEGATE0( unsigned int,	ReadUBitVar );
	DELEGATE0( float, ReadBitCoord);
	DELEGATE2( float, ReadBitCoordMP, bool, bool );
	DELEGATE0( float, ReadBitFloat);
	DELEGATE0( float, ReadBitNormal);
	DELEGATE1( bool,Seek, int );
	DELEGATE1( float, ReadBitAngle, int );
	DELEGATE1( bool,SeekRelative,int);
	DELEGATE0I( GetNumBitsLeft );
	DELEGATE0I( TotalBytesAvailable );

	void SetOverflowFlag()
	{
		old1.SetOverflowFlag();
		new1.SetOverflowFlag();
		Check();
	}

	bool ReadString( char *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL )
	{
		Check();
		int oldn, newn;
		bool bOld = old1.ReadString( pStr, bufLen, bLine, &oldn );
		bool bNew = new1.ReadString( pStr, bufLen, bLine, &newn );
		Assert( bOld == bNew );
		Assert( oldn == newn );
		if ( pOutNumChars )
			*pOutNumChars = oldn;
		Check();
		return bOld;
	}

	bool ReadWString( wchar_t *pStr, int bufLen, bool bLine=false, int *pOutNumChars=NULL )
	{
		Check();
		int oldn, newn;
		bool bOld = old1.ReadWString( pStr, bufLen, bLine, &oldn );
		bool bNew = new1.ReadWString( pStr, bufLen, bLine, &newn );
		Assert( bOld == bNew );
		Assert( oldn == newn );
		if ( pOutNumChars )
			*pOutNumChars = oldn;
		Check();
		return bOld;
	}

	void ReadBitVec3Coord( Vector& fa )
	{
		Check();
		old1.ReadBitVec3Coord( fa );
		Vector test;
		new1.ReadBitVec3Coord( test );
		Assert( VectorsAreEqual( fa, test ));
		Check();
	}
	void ReadBitVec3Normal( Vector& fa )
	{
		Check();
		old1.ReadBitVec3Coord( fa );
		Vector test;
		new1.ReadBitVec3Coord( test );
		Assert( VectorsAreEqual( fa, test ));
		Check();
	}
	
	char* ReadAndAllocateString( bool *pOverflow = NULL )
	{
		Check();
		bool bold, bnew;
		char *pold = old1.ReadAndAllocateString( &bold );
		char *pnew = new1.ReadAndAllocateString( &bnew );
		Assert( bold == bnew );
		Assert(strcmp( pold, pnew ) == 0 );
		delete[] pnew;
		Check();
		if ( pOverflow )
			*pOverflow = bold;
		return pold;

	}

	DELEGATE1( int, ReadSBitLong, int );

};
#endif


WRAP_READ( CBitRead );

#endif