#ifndef BITBUF_H
#define BITBUF_H

#ifdef _WIN32
#pragma once
#endif


#include "mathlib.h"
#include "vector.h"
#include "basetypes.h"

#if _DEBUG
#define BITBUF_INLINE inline
#else
#define BITBUF_INLINE FORCEINLINE
#endif

class Vector;
class QAngle;

typedef enum
{
	BITBUFERROR_VALUE_OUT_OF_RANGE = 0,		         
	BITBUFERROR_BUFFER_OVERRUN,				      

	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


void SetBitBufErrorHandler(BitBufErrorHandler fn);


inline int BitByte(int bits)
{
	return (bits + 7) >> 3;
}

namespace bitbuf
{
	inline uint32 ZigZagEncode32(int32 n)
	{
		return(n << 1) ^ (n >> 31);
	}

	inline int32 ZigZagDecode32(uint32 n)
	{
		return(n >> 1) ^ -static_cast<int32>(n & 1);
	}

	inline uint64 ZigZagEncode64(int64 n)
	{
		return(n << 1) ^ (n >> 63);
	}

	inline int64 ZigZagDecode64(uint64 n)
	{
		return(n >> 1) ^ -static_cast<int64>(n & 1);
	}

	const int kMaxVarintBytes = 10;
	const int kMaxVarint32Bytes = 5;
}

class bf_write
{
public:
	bf_write();

	bf_write(void* pData, int nBytes, int nMaxBits = -1);
	bf_write(const char* pDebugName, void* pData, int nBytes, int nMaxBits = -1);

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

	void			Reset();

	unsigned char* GetBasePointer() { return (unsigned char*)m_pData; }

	void			SetAssertOnOverflow(bool bAssert);

	const char* GetDebugName();
	void			SetDebugName(const char* pDebugName);


public:

	void			SeekToBit(int bitPos);


public:

	void			WriteOneBit(int nValue);
	void			WriteOneBitNoCheck(int nValue);
	void			WriteOneBitAt(int iBit, int nValue);

	void			WriteUBitLong(unsigned int data, int numbits, bool bCheckRange = true);
	void			WriteSBitLong(int data, int numbits);

	void			WriteBitLong(unsigned int data, int numbits, bool bSigned);

	bool			WriteBits(const void* pIn, int nBits);

	void			WriteUBitVar(unsigned int data);

	void			WriteVarInt32(uint32 data);
	void			WriteVarInt64(uint64 data);
	void			WriteSignedVarInt32(int32 data);
	void			WriteSignedVarInt64(int64 data);
	int				ByteSizeVarInt32(uint32 data);
	int				ByteSizeVarInt64(uint64 data);
	int				ByteSizeSignedVarInt32(int32 data);
	int				ByteSizeSignedVarInt64(int64 data);

	bool			WriteBitsFromBuffer(class bf_read* pIn, int nBits);

	void			WriteBitAngle(float fAngle, int numbits);
	void			WriteBitCoord(const float f);
	void			WriteBitCoordMP(const float f, bool bIntegral, bool bLowPrecision);
	void			WriteBitFloat(float val);
	void			WriteBitVec3Coord(const Vector& fa);
	void			WriteBitNormal(float f);
	void			WriteBitVec3Normal(const Vector& fa);
	void			WriteBitAngles(const QAngle& fa);


public:

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

	bool			WriteString(const char* pStr);


public:

	int				GetNumBytesWritten() const;
	int				GetNumBitsWritten() const;
	int				GetMaxNumBits();
	int				GetNumBitsLeft();
	int				GetNumBytesLeft();
	unsigned char* GetData();
	const unsigned char* GetData() const;

	bool			CheckForOverflow(int nBits);
	inline bool		IsOverflowed() const { return m_bOverflow; }

	void			SetOverflowFlag();


public:
	unsigned long* RESTRICT m_pData;
	int				m_nDataBytes;
	int				m_nDataBits;

	int				m_iCurBit;

private:

	bool			m_bOverflow;

	bool			m_bAssertOnOverflow;
	const char* m_pDebugName;
};


inline int bf_write::GetNumBytesWritten() const
{
	return BitByte(m_iCurBit);
}

inline int bf_write::GetNumBitsWritten() const
{
	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 (unsigned char*)m_pData;
}

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

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

	return m_bOverflow;
}

BITBUF_INLINE void bf_write::SetOverflowFlag()
{
#ifdef DBGFLAG_ASSERT
	if (m_bAssertOnOverflow)
	{
		Assert(false);
	}
#endif
	m_bOverflow = true;
}

BITBUF_INLINE void bf_write::WriteOneBitNoCheck(int nValue)
{
#if __i386__
	if (nValue)
		m_pData[m_iCurBit >> 5] |= 1u << (m_iCurBit & 31);
	else
		m_pData[m_iCurBit >> 5] &= ~(1u << (m_iCurBit & 31));
#else
	extern unsigned long g_LittleBits[32];
	if (nValue)
		m_pData[m_iCurBit >> 5] |= g_LittleBits[m_iCurBit & 31];
	else
		m_pData[m_iCurBit >> 5] &= ~g_LittleBits[m_iCurBit & 31];
#endif

	++m_iCurBit;
}

inline void bf_write::WriteOneBit(int nValue)
{
	if (m_iCurBit >= m_nDataBits)
	{
		SetOverflowFlag();
		CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN, GetDebugName());
		return;
	}
	WriteOneBitNoCheck(nValue);
}


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

#if __i386__
	if (nValue)
		m_pData[iBit >> 5] |= 1u << (iBit & 31);
	else
		m_pData[iBit >> 5] &= ~(1u << (iBit & 31));
#else
	extern unsigned long g_LittleBits[32];
	if (nValue)
		m_pData[iBit >> 5] |= g_LittleBits[iBit & 31];
	else
		m_pData[iBit >> 5] &= ~g_LittleBits[iBit & 31];
#endif
}

BITBUF_INLINE void bf_write::WriteUBitLong(unsigned int curData, int numbits, bool bCheckRange) RESTRICT
{
#ifdef _DEBUG
	if (bCheckRange && numbits < 32)
	{
		if (curData >= (unsigned long)(1 << numbits))
		{
			CallErrorHandler(BITBUFERROR_VALUE_OUT_OF_RANGE, GetDebugName());
		}
	}
	Assert(numbits >= 0 && numbits <= 32);
#endif

	if (GetNumBitsLeft() < numbits)
	{
		m_iCurBit = m_nDataBits;
		SetOverflowFlag();
		CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN, GetDebugName());
		return;
	}

	int iCurBitMasked = m_iCurBit & 31;
	int iDWord = m_iCurBit >> 5;
	m_iCurBit += numbits;

	Assert((iDWord * 4 + sizeof(long)) <= (unsigned int)m_nDataBytes);
	unsigned long* RESTRICT pOut = &m_pData[iDWord];

	curData = (curData << iCurBitMasked) | (curData >> (32 - iCurBitMasked));

	unsigned int temp = 1 << (numbits - 1);
	unsigned int mask1 = (temp * 2 - 1) << iCurBitMasked;
	unsigned int mask2 = (temp - 1) >> (31 - iCurBitMasked);

	int i = mask2 & 1;
	unsigned long dword1 = LoadLittleDWord(pOut, 0);
	unsigned long dword2 = LoadLittleDWord(pOut, i);

	dword1 ^= (mask1 & (curData ^ dword1));
	dword2 ^= (mask2 & (curData ^ dword2));

	StoreLittleDWord(pOut, i, dword2);
	StoreLittleDWord(pOut, 0, dword1);
}

BITBUF_INLINE void bf_write::WriteUBitVar(unsigned int data)
{
	int n = (data < 0x10u ? -1 : 0) + (data < 0x100u ? -1 : 0) + (data < 0x1000u ? -1 : 0);
	WriteUBitLong(data * 4 + n + 3, 6 + n * 4 + 12);
	if (data >= 0x1000u)
	{
		WriteUBitLong(data >> 16, 16);
	}
}

BITBUF_INLINE void bf_write::WriteBitFloat(float val)
{
	long intVal;

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

	intVal = *((long*)&val);
	WriteUBitLong(intVal, 32);
}

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];
};



class bf_read
{
public:
	bf_read();

	bf_read(const void* pData, int nBytes, int nBits = -1);
	bf_read(const char* pDebugName, const void* pData, int nBytes, int nBits = -1);

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

	void			Reset();

	void			SetAssertOnOverflow(bool bAssert);

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

	void			ExciseBits(int startbit, int bitstoremove);


public:

	int				ReadOneBit();


protected:

	unsigned int	CheckReadUBitLong(int numbits);		  
	int				ReadOneBitNoCheck();				        
	bool			CheckForOverflow(int nBits);


public:

	const unsigned char* GetBasePointer() { return m_pData; }

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

	void            ReadBits(void* pOut, int nBits);
	int             ReadBitsClamped_ptr(void* pOut, size_t outSizeBytes, size_t nBits);
	template <typename T, size_t N>
	int             ReadBitsClamped(T(&pOut)[N], size_t nBits)
	{
		return ReadBitsClamped_ptr(pOut, N * sizeof(T), nBits);
	}

	float			ReadBitAngle(int numbits);

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

	unsigned int	ReadUBitVar();
	unsigned int	ReadUBitVarInternal(int encodingType);

	uint32			ReadVarInt32();
	uint64			ReadVarInt64();
	int32			ReadSignedVarInt32();
	int64			ReadSignedVarInt64();

	unsigned int	ReadBitLong(int numbits, bool bSigned);

	float			ReadBitCoord();
	float			ReadBitCoordMP(bool bIntegral, bool bLowPrecision);
	float			ReadBitFloat();
	float			ReadBitNormal();
	void			ReadBitVec3Coord(Vector& fa);
	void			ReadBitVec3Normal(Vector& fa);
	void			ReadBitAngles(QAngle& fa);

	unsigned int	ReadBitCoordBits();
	unsigned int	ReadBitCoordMPBits(bool bIntegral, bool bLowPrecision);

public:

	BITBUF_INLINE int	ReadChar() { return (char)ReadUBitLong(8); }
	BITBUF_INLINE int	ReadByte() { return ReadUBitLong(8); }
	BITBUF_INLINE int	ReadShort() { return (short)ReadUBitLong(16); }
	BITBUF_INLINE int	ReadWord() { return ReadUBitLong(16); }
	BITBUF_INLINE long ReadLong() { return ReadUBitLong(32); }
	int64			ReadLongLong();
	float			ReadFloat();
	bool			ReadBytes(void* pOut, int nBytes);

	bool			ReadString(char* pStr, int bufLen, bool bLine = false, int* pOutNumChars = NULL);

	char* ReadAndAllocateString(bool* pOverflow = 0);

	int				CompareBits(bf_read* RESTRICT other, int bits) RESTRICT;
	int				CompareBitsAt(int offset, bf_read* RESTRICT other, int otherOffset, int bits) RESTRICT;

public:
	int				GetNumBytesLeft();
	int				GetNumBytesRead();
	int				GetNumBitsLeft();
	int				GetNumBitsRead() const;

	inline bool		IsOverflowed() const { return m_bOverflow; }

	inline bool		Seek(int iBit);					     
	inline bool		SeekRelative(int iBitDelta);	        

	void			SetOverflowFlag();


public:

	const unsigned char* RESTRICT m_pData;
	int						m_nDataBytes;
	int						m_nDataBits;

	int				m_iCurBit;


private:
	bool			m_bOverflow;

	bool			m_bAssertOnOverflow;

	const char* m_pDebugName;
};

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

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

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

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

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

inline bool	bf_read::SeekRelative(int iBitDelta)
{
	return Seek(m_iCurBit + iBitDelta);
}

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

	return m_bOverflow;
}

inline int bf_read::ReadOneBitNoCheck()
{
#if VALVE_LITTLE_ENDIAN
	unsigned int value = ((unsigned long* RESTRICT)m_pData)[m_iCurBit >> 5] >> (m_iCurBit & 31);
#else
	unsigned char value = m_pData[m_iCurBit >> 3] >> (m_iCurBit & 7);
#endif
	++m_iCurBit;
	return value & 1;
}

inline int bf_read::ReadOneBit()
{
	if (GetNumBitsLeft() <= 0)
	{
		SetOverflowFlag();
		CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN, GetDebugName());
		return 0;
	}
	return ReadOneBitNoCheck();
}

inline float bf_read::ReadBitFloat()
{
	union { uint32 u; float f; } c = { ReadUBitLong(32) };
	return c.f;
}

BITBUF_INLINE unsigned int bf_read::ReadUBitVar()
{
	unsigned int sixbits = ReadUBitLong(6);
	unsigned int encoding = sixbits & 3;
	if (encoding)
	{
		return ReadUBitVarInternal(encoding);
	}
	return sixbits >> 2;
}

BITBUF_INLINE unsigned int bf_read::ReadUBitLong(int numbits) RESTRICT
{
	Assert(numbits > 0 && numbits <= 32);

	if (GetNumBitsLeft() < numbits)
	{
		m_iCurBit = m_nDataBits;
		SetOverflowFlag();
		CallErrorHandler(BITBUFERROR_BUFFER_OVERRUN, GetDebugName());
		return 0;
	}

	unsigned int iStartBit = m_iCurBit & 31u;
	int iLastBit = m_iCurBit + numbits - 1;
	unsigned int iWordOffset1 = m_iCurBit >> 5;
	unsigned int iWordOffset2 = iLastBit >> 5;
	m_iCurBit += numbits;

#if __i386__
	unsigned int bitmask = (2 << (numbits - 1)) - 1;
#else
	extern unsigned long g_ExtraMasks[33];
	unsigned int bitmask = g_ExtraMasks[numbits];
#endif

	unsigned int dw1 = LoadLittleDWord((unsigned long* RESTRICT)m_pData, iWordOffset1) >> iStartBit;
	unsigned int dw2 = LoadLittleDWord((unsigned long* RESTRICT)m_pData, iWordOffset2) << (32 - iStartBit);

	return (dw1 | dw2) & bitmask;
}

BITBUF_INLINE int bf_read::CompareBits(bf_read* RESTRICT other, int numbits) RESTRICT
{
	return (ReadUBitLong(numbits) != other->ReadUBitLong(numbits));
}


#endif