//========= Copyright © 1996-2007, Valve Corporation, All rights reserved. ============//
//
//	LZMA Codec.
//
//	LZMA SDK 4.43 Copyright (c) 1999-2006 Igor Pavlov (2006-05-01)
//	http://www.7-zip.org/
//
//=====================================================================================//

#include "tier0/platform.h"
#include "tier0/dbg.h"
#include "tier1/lzmaDecoder.h"

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"

#ifndef _7ZIP_BYTE_DEFINED
#define _7ZIP_BYTE_DEFINED
typedef unsigned char Byte;
#endif 

#ifndef _7ZIP_UINT16_DEFINED
#define _7ZIP_UINT16_DEFINED
typedef unsigned short UInt16;
#endif 

#ifndef _7ZIP_UINT32_DEFINED
#define _7ZIP_UINT32_DEFINED
#ifdef _LZMA_UINT32_IS_ULONG
typedef unsigned long UInt32;
#else
typedef unsigned int UInt32;
#endif
#endif 

/* #define _LZMA_SYSTEM_SIZE_T */
/* Use system's size_t. You can use it to enable 64-bit sizes supporting */

#ifndef _7ZIP_SIZET_DEFINED
#define _7ZIP_SIZET_DEFINED
#ifdef _LZMA_SYSTEM_SIZE_T
#include <stddef.h>
typedef size_t SizeT;
#else
typedef UInt32 SizeT;
#endif
#endif

/* #define _LZMA_IN_CB */
/* Use callback for input data */

/* #define _LZMA_OUT_READ */
/* Use read function for output data */

#define _LZMA_PROB32
/* It can increase speed on some 32-bit CPUs, 
but memory usage will be doubled in that case */

/* #define _LZMA_LOC_OPT */
/* Enable local speed optimizations inside code */

#ifdef _LZMA_PROB32
#define CProb UInt32
#else
#define CProb UInt16
#endif

#define LZMA_RESULT_OK 0
#define LZMA_RESULT_DATA_ERROR 1

#ifdef _LZMA_IN_CB
typedef struct _ILzmaInCallback
{
	int (*Read)(void *object, const unsigned char **buffer, SizeT *bufferSize);
} ILzmaInCallback;
#endif

#define LZMA_BASE_SIZE 1846
#define LZMA_LIT_SIZE 768

#define LZMA_PROPERTIES_SIZE 5

typedef struct _CLzmaProperties
{
	int lc;
	int lp;
	int pb;
#ifdef _LZMA_OUT_READ
	UInt32 DictionarySize;
#endif
}CLzmaProperties;

int LzmaDecodeProperties(CLzmaProperties *propsRes, const unsigned char *propsData, int size);

#define LzmaGetNumProbs(Properties) (LZMA_BASE_SIZE + (LZMA_LIT_SIZE << ((Properties)->lc + (Properties)->lp)))

#define kLzmaNeedInitId (-2)

typedef struct _CLzmaDecoderState
{
	CLzmaProperties Properties;
	CProb *Probs;

#ifdef _LZMA_IN_CB
	const unsigned char *Buffer;
	const unsigned char *BufferLim;
#endif

#ifdef _LZMA_OUT_READ
	unsigned char *Dictionary;
	UInt32 Range;
	UInt32 Code;
	UInt32 DictionaryPos;
	UInt32 GlobalPos;
	UInt32 DistanceLimit;
	UInt32 Reps[4];
	int State;
	int RemainLen;
	unsigned char TempDictionary[4];
#endif
} CLzmaDecoderState;

#ifdef _LZMA_OUT_READ
#define LzmaDecoderInit(vs) { (vs)->RemainLen = kLzmaNeedInitId; }
#endif

int LzmaDecode(CLzmaDecoderState *vs,
#ifdef _LZMA_IN_CB
			   ILzmaInCallback *inCallback,
#else
			   const unsigned char *inStream, SizeT inSize, SizeT *inSizeProcessed,
#endif
			   unsigned char *outStream, SizeT outSize, SizeT *outSizeProcessed);

#define kNumTopBits 24
#define kTopValue ((UInt32)1 << kNumTopBits)

#define kNumBitModelTotalBits 11
#define kBitModelTotal (1 << kNumBitModelTotalBits)
#define kNumMoveBits 5

#define RC_READ_BYTE (*Buffer++)

#define RC_INIT2 Code = 0; Range = 0xFFFFFFFF; \
{ int i; for(i = 0; i < 5; i++) { RC_TEST; Code = (Code << 8) | RC_READ_BYTE; }}

#ifdef _LZMA_IN_CB

#define RC_TEST { if (Buffer == BufferLim) \
{ SizeT size; int result = InCallback->Read(InCallback, &Buffer, &size); if (result != LZMA_RESULT_OK) return result; \
	BufferLim = Buffer + size; if (size == 0) return LZMA_RESULT_DATA_ERROR; }}

#define RC_INIT Buffer = BufferLim = 0; RC_INIT2

#else

#define RC_TEST { if (Buffer == BufferLim) return LZMA_RESULT_DATA_ERROR; }

#define RC_INIT(buffer, bufferSize) Buffer = buffer; BufferLim = buffer + bufferSize; RC_INIT2

#endif

#define RC_NORMALIZE if (Range < kTopValue) { RC_TEST; Range <<= 8; Code = (Code << 8) | RC_READ_BYTE; }

#define IfBit0(p) RC_NORMALIZE; bound = (Range >> kNumBitModelTotalBits) * *(p); if (Code < bound)
#define UpdateBit0(p) Range = bound; *(p) += (kBitModelTotal - *(p)) >> kNumMoveBits;
#define UpdateBit1(p) Range -= bound; Code -= bound; *(p) -= (*(p)) >> kNumMoveBits;

#define RC_GET_BIT2(p, mi, A0, A1) IfBit0(p) \
{ UpdateBit0(p); mi <<= 1; A0; } else \
{ UpdateBit1(p); mi = (mi + mi) + 1; A1; } 

#define RC_GET_BIT(p, mi) RC_GET_BIT2(p, mi, ; , ;)               

#define RangeDecoderBitTreeDecode(probs, numLevels, res) \
{ int i = numLevels; res = 1; \
	do { CProb *p = probs + res; RC_GET_BIT(p, res) } while(--i != 0); \
	res -= (1 << numLevels); }


#define kNumPosBitsMax 4
#define kNumPosStatesMax (1 << kNumPosBitsMax)

#define kLenNumLowBits 3
#define kLenNumLowSymbols (1 << kLenNumLowBits)
#define kLenNumMidBits 3
#define kLenNumMidSymbols (1 << kLenNumMidBits)
#define kLenNumHighBits 8
#define kLenNumHighSymbols (1 << kLenNumHighBits)

#define LenChoice 0
#define LenChoice2 (LenChoice + 1)
#define LenLow (LenChoice2 + 1)
#define LenMid (LenLow + (kNumPosStatesMax << kLenNumLowBits))
#define LenHigh (LenMid + (kNumPosStatesMax << kLenNumMidBits))
#define kNumLenProbs (LenHigh + kLenNumHighSymbols) 


#define kNumStates 12
#define kNumLitStates 7

#define kStartPosModelIndex 4
#define kEndPosModelIndex 14
#define kNumFullDistances (1 << (kEndPosModelIndex >> 1))

#define kNumPosSlotBits 6
#define kNumLenToPosStates 4

#define kNumAlignBits 4
#define kAlignTableSize (1 << kNumAlignBits)

#define kMatchMinLen 2

#define IsMatch 0
#define IsRep (IsMatch + (kNumStates << kNumPosBitsMax))
#define IsRepG0 (IsRep + kNumStates)
#define IsRepG1 (IsRepG0 + kNumStates)
#define IsRepG2 (IsRepG1 + kNumStates)
#define IsRep0Long (IsRepG2 + kNumStates)
#define PosSlot (IsRep0Long + (kNumStates << kNumPosBitsMax))
#define SpecPos (PosSlot + (kNumLenToPosStates << kNumPosSlotBits))
#define Align (SpecPos + kNumFullDistances - kEndPosModelIndex)
#define LenCoder (Align + kAlignTableSize)
#define RepLenCoder (LenCoder + kNumLenProbs)
#define Literal (RepLenCoder + kNumLenProbs)

#if Literal != LZMA_BASE_SIZE
StopCompilingDueBUG
#endif

int LzmaDecodeProperties(CLzmaProperties *propsRes, const unsigned char *propsData, int size)
{
	unsigned char prop0;
	if (size < LZMA_PROPERTIES_SIZE)
		return LZMA_RESULT_DATA_ERROR;
	prop0 = propsData[0];
	if (prop0 >= (9 * 5 * 5))
		return LZMA_RESULT_DATA_ERROR;
	{
		for (propsRes->pb = 0; prop0 >= (9 * 5); propsRes->pb++, prop0 -= (9 * 5));
		for (propsRes->lp = 0; prop0 >= 9; propsRes->lp++, prop0 -= 9);
		propsRes->lc = prop0;
		/*
		unsigned char remainder = (unsigned char)(prop0 / 9);
		propsRes->lc = prop0 % 9;
		propsRes->pb = remainder / 5;
		propsRes->lp = remainder % 5;
		*/
	}

#ifdef _LZMA_OUT_READ
	{
		int i;
		propsRes->DictionarySize = 0;
		for (i = 0; i < 4; i++)
			propsRes->DictionarySize += (UInt32)(propsData[1 + i]) << (i * 8);
		if (propsRes->DictionarySize == 0)
			propsRes->DictionarySize = 1;
	}
#endif
	return LZMA_RESULT_OK;
}

#define kLzmaStreamWasFinishedId (-1)

int LzmaDecode(CLzmaDecoderState *vs,
#ifdef _LZMA_IN_CB
			   ILzmaInCallback *InCallback,
#else
			   const unsigned char *inStream, SizeT inSize, SizeT *inSizeProcessed,
#endif
			   unsigned char *outStream, SizeT outSize, SizeT *outSizeProcessed)
{
	CProb *p = vs->Probs;
	SizeT nowPos = 0;
	Byte previousByte = 0;
	UInt32 posStateMask = (1 << (vs->Properties.pb)) - 1;
	UInt32 literalPosMask = (1 << (vs->Properties.lp)) - 1;
	int lc = vs->Properties.lc;

#ifdef _LZMA_OUT_READ

	UInt32 Range = vs->Range;
	UInt32 Code = vs->Code;
#ifdef _LZMA_IN_CB
	const Byte *Buffer = vs->Buffer;
	const Byte *BufferLim = vs->BufferLim;
#else
	const Byte *Buffer = inStream;
	const Byte *BufferLim = inStream + inSize;
#endif
	int state = vs->State;
	UInt32 rep0 = vs->Reps[0], rep1 = vs->Reps[1], rep2 = vs->Reps[2], rep3 = vs->Reps[3];
	int len = vs->RemainLen;
	UInt32 globalPos = vs->GlobalPos;
	UInt32 distanceLimit = vs->DistanceLimit;

	Byte *dictionary = vs->Dictionary;
	UInt32 dictionarySize = vs->Properties.DictionarySize;
	UInt32 dictionaryPos = vs->DictionaryPos;

	Byte tempDictionary[4];

#ifndef _LZMA_IN_CB
	*inSizeProcessed = 0;
#endif
	*outSizeProcessed = 0;
	if (len == kLzmaStreamWasFinishedId)
		return LZMA_RESULT_OK;

	if (dictionarySize == 0)
	{
		dictionary = tempDictionary;
		dictionarySize = 1;
		tempDictionary[0] = vs->TempDictionary[0];
	}

	if (len == kLzmaNeedInitId)
	{
		{
			UInt32 numProbs = Literal + ((UInt32)LZMA_LIT_SIZE << (lc + vs->Properties.lp));
			UInt32 i;
			for (i = 0; i < numProbs; i++)
				p[i] = kBitModelTotal >> 1; 
			rep0 = rep1 = rep2 = rep3 = 1;
			state = 0;
			globalPos = 0;
			distanceLimit = 0;
			dictionaryPos = 0;
			dictionary[dictionarySize - 1] = 0;
#ifdef _LZMA_IN_CB
			RC_INIT;
#else
			RC_INIT(inStream, inSize);
#endif
		}
		len = 0;
	}
	while(len != 0 && nowPos < outSize)
	{
		UInt32 pos = dictionaryPos - rep0;
		if (pos >= dictionarySize)
			pos += dictionarySize;
		outStream[nowPos++] = dictionary[dictionaryPos] = dictionary[pos];
		if (++dictionaryPos == dictionarySize)
			dictionaryPos = 0;
		len--;
	}
	if (dictionaryPos == 0)
		previousByte = dictionary[dictionarySize - 1];
	else
		previousByte = dictionary[dictionaryPos - 1];

#else /* if !_LZMA_OUT_READ */

	int state = 0;
	UInt32 rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
	int len = 0;
	const Byte *Buffer;
	const Byte *BufferLim;
	UInt32 Range;
	UInt32 Code;

#ifndef _LZMA_IN_CB
	*inSizeProcessed = 0;
#endif
	*outSizeProcessed = 0;

	{
		UInt32 i;
		UInt32 numProbs = Literal + ((UInt32)LZMA_LIT_SIZE << (lc + vs->Properties.lp));
		for (i = 0; i < numProbs; i++)
			p[i] = kBitModelTotal >> 1;
	}

#ifdef _LZMA_IN_CB
	RC_INIT;
#else
	RC_INIT(inStream, inSize);
#endif

#endif /* _LZMA_OUT_READ */

	while(nowPos < outSize)
	{
		CProb *prob;
		UInt32 bound;
		int posState = (int)(
			(nowPos 
#ifdef _LZMA_OUT_READ
			+ globalPos
#endif
			)
			& posStateMask);

		prob = p + IsMatch + (state << kNumPosBitsMax) + posState;
		IfBit0(prob)
		{
			int symbol = 1;
			UpdateBit0(prob)
				prob = p + Literal + (LZMA_LIT_SIZE * 
				(((
				(nowPos 
#ifdef _LZMA_OUT_READ
				+ globalPos
#endif
				)
				& literalPosMask) << lc) + (previousByte >> (8 - lc))));

			if (state >= kNumLitStates)
			{
				int matchByte;
#ifdef _LZMA_OUT_READ
				UInt32 pos = dictionaryPos - rep0;
				if (pos >= dictionarySize)
					pos += dictionarySize;
				matchByte = dictionary[pos];
#else
				matchByte = outStream[nowPos - rep0];
#endif
				do
				{
					int bit;
					CProb *probLit;
					matchByte <<= 1;
					bit = (matchByte & 0x100);
					probLit = prob + 0x100 + bit + symbol;
					RC_GET_BIT2(probLit, symbol, if (bit != 0) break, if (bit == 0) break)
				}
				while (symbol < 0x100);
			}
			while (symbol < 0x100)
			{
				CProb *probLit = prob + symbol;
				RC_GET_BIT(probLit, symbol)
			}
			previousByte = (Byte)symbol;

			outStream[nowPos++] = previousByte;
#ifdef _LZMA_OUT_READ
			if (distanceLimit < dictionarySize)
				distanceLimit++;

			dictionary[dictionaryPos] = previousByte;
			if (++dictionaryPos == dictionarySize)
				dictionaryPos = 0;
#endif
			if (state < 4) state = 0;
			else if (state < 10) state -= 3;
			else state -= 6;
		}
else             
{
	UpdateBit1(prob);
	prob = p + IsRep + state;
	IfBit0(prob)
	{
		UpdateBit0(prob);
		rep3 = rep2;
		rep2 = rep1;
		rep1 = rep0;
		state = state < kNumLitStates ? 0 : 3;
		prob = p + LenCoder;
	}
	  else
	  {
		  UpdateBit1(prob);
		  prob = p + IsRepG0 + state;
		  IfBit0(prob)
		  {
			  UpdateBit0(prob);
			  prob = p + IsRep0Long + (state << kNumPosBitsMax) + posState;
			  IfBit0(prob)
			  {
#ifdef _LZMA_OUT_READ
				  UInt32 pos;
#endif
				  UpdateBit0(prob);

#ifdef _LZMA_OUT_READ
				  if (distanceLimit == 0)
#else
				  if (nowPos == 0)
#endif
					  return LZMA_RESULT_DATA_ERROR;

				  state = state < kNumLitStates ? 9 : 11;
#ifdef _LZMA_OUT_READ
				  pos = dictionaryPos - rep0;
				  if (pos >= dictionarySize)
					  pos += dictionarySize;
				  previousByte = dictionary[pos];
				  dictionary[dictionaryPos] = previousByte;
				  if (++dictionaryPos == dictionarySize)
					  dictionaryPos = 0;
#else
				  previousByte = outStream[nowPos - rep0];
#endif
				  outStream[nowPos++] = previousByte;
#ifdef _LZMA_OUT_READ
				  if (distanceLimit < dictionarySize)
					  distanceLimit++;
#endif

				  continue;
			  }
		  else
		  {
			  UpdateBit1(prob);
		  }
		  }
		else
		{
			UInt32 distance;
			UpdateBit1(prob);
			prob = p + IsRepG1 + state;
			IfBit0(prob)
			{
				UpdateBit0(prob);
				distance = rep1;
			}
		  else 
		  {
			  UpdateBit1(prob);
			  prob = p + IsRepG2 + state;
			  IfBit0(prob)
			  {
				  UpdateBit0(prob);
				  distance = rep2;
			  }
			else
			{
				UpdateBit1(prob);
				distance = rep3;
				rep3 = rep2;
			}
			rep2 = rep1;
		  }
		  rep1 = rep0;
		  rep0 = distance;
		}
		state = state < kNumLitStates ? 8 : 11;
		prob = p + RepLenCoder;
	  }
	  {
		  int numBits, offset;
		  CProb *probLen = prob + LenChoice;
		  IfBit0(probLen)
		  {
			  UpdateBit0(probLen);
			  probLen = prob + LenLow + (posState << kLenNumLowBits);
			  offset = 0;
			  numBits = kLenNumLowBits;
		  }
		else
		{
			UpdateBit1(probLen);
			probLen = prob + LenChoice2;
			IfBit0(probLen)
			{
				UpdateBit0(probLen);
				probLen = prob + LenMid + (posState << kLenNumMidBits);
				offset = kLenNumLowSymbols;
				numBits = kLenNumMidBits;
			}
		  else
		  {
			  UpdateBit1(probLen);
			  probLen = prob + LenHigh;
			  offset = kLenNumLowSymbols + kLenNumMidSymbols;
			  numBits = kLenNumHighBits;
		  }
		}
		RangeDecoderBitTreeDecode(probLen, numBits, len);
		len += offset;
	  }

	  if (state < 4)
	  {
		  int posSlot;
		  state += kNumLitStates;
		  prob = p + PosSlot +
			  ((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) << 
			  kNumPosSlotBits);
		  RangeDecoderBitTreeDecode(prob, kNumPosSlotBits, posSlot);
		  if (posSlot >= kStartPosModelIndex)
		  {
			  int numDirectBits = ((posSlot >> 1) - 1);
			  rep0 = (2 | ((UInt32)posSlot & 1));
			  if (posSlot < kEndPosModelIndex)
			  {
				  rep0 <<= numDirectBits;
				  prob = p + SpecPos + rep0 - posSlot - 1;
			  }
			  else
			  {
				  numDirectBits -= kNumAlignBits;
				  do
				  {
					  RC_NORMALIZE
						  Range >>= 1;
					  rep0 <<= 1;
					  if (Code >= Range)
					  {
						  Code -= Range;
						  rep0 |= 1;
					  }
				  }
				  while (--numDirectBits != 0);
				  prob = p + Align;
				  rep0 <<= kNumAlignBits;
				  numDirectBits = kNumAlignBits;
			  }
			  {
				  int i = 1;
				  int mi = 1;
				  do
				  {
					  CProb *prob3 = prob + mi;
					  RC_GET_BIT2(prob3, mi, ; , rep0 |= i);
					  i <<= 1;
				  }
				  while(--numDirectBits != 0);
			  }
		  }
		  else
			  rep0 = posSlot;
		  if (++rep0 == (UInt32)(0))
		  {
			  /* it's for stream version */
			  len = kLzmaStreamWasFinishedId;
			  break;
		  }
	  }

	  len += kMatchMinLen;
#ifdef _LZMA_OUT_READ
	  if (rep0 > distanceLimit) 
#else
	  if (rep0 > nowPos)
#endif
		  return LZMA_RESULT_DATA_ERROR;

#ifdef _LZMA_OUT_READ
	  if (dictionarySize - distanceLimit > (UInt32)len)
		  distanceLimit += len;
	  else
		  distanceLimit = dictionarySize;
#endif

	  do
	  {
#ifdef _LZMA_OUT_READ
		  UInt32 pos = dictionaryPos - rep0;
		  if (pos >= dictionarySize)
			  pos += dictionarySize;
		  previousByte = dictionary[pos];
		  dictionary[dictionaryPos] = previousByte;
		  if (++dictionaryPos == dictionarySize)
			  dictionaryPos = 0;
#else
		  previousByte = outStream[nowPos - rep0];
#endif
		  len--;
		  outStream[nowPos++] = previousByte;
	  }
	  while(len != 0 && nowPos < outSize);
}
	}
	RC_NORMALIZE;

#ifdef _LZMA_OUT_READ
	vs->Range = Range;
	vs->Code = Code;
	vs->DictionaryPos = dictionaryPos;
	vs->GlobalPos = globalPos + (UInt32)nowPos;
	vs->DistanceLimit = distanceLimit;
	vs->Reps[0] = rep0;
	vs->Reps[1] = rep1;
	vs->Reps[2] = rep2;
	vs->Reps[3] = rep3;
	vs->State = state;
	vs->RemainLen = len;
	vs->TempDictionary[0] = tempDictionary[0];
#endif

#ifdef _LZMA_IN_CB
	vs->Buffer = Buffer;
	vs->BufferLim = BufferLim;
#else
	*inSizeProcessed = (SizeT)(Buffer - inStream);
#endif
	*outSizeProcessed = nowPos;
	return LZMA_RESULT_OK;
}

//-----------------------------------------------------------------------------
// Returns true if buffer is compressed.
//-----------------------------------------------------------------------------
bool CLZMA::IsCompressed( unsigned char *pInput )
{
	lzma_header_t *pHeader = (lzma_header_t *)pInput;
	if ( pHeader && pHeader->id == LZMA_ID )
	{
		return true;
	}

	// unrecognized
	return false;
}

//-----------------------------------------------------------------------------
// Returns uncompressed size of compressed input buffer. Used for allocating output
// buffer for decompression. Returns 0 if input buffer is not compressed.
//-----------------------------------------------------------------------------
unsigned int CLZMA::GetActualSize( unsigned char *pInput )
{
	lzma_header_t *pHeader = (lzma_header_t *)pInput;
	if ( pHeader && pHeader->id == LZMA_ID )
	{
		return LittleLong( pHeader->actualSize );
	}

	// unrecognized
	return 0;
}

//-----------------------------------------------------------------------------
// Uncompress a buffer, Returns the uncompressed size. Caller must provide an
// adequate sized output buffer or memory corruption will occur.
//-----------------------------------------------------------------------------
unsigned int CLZMA::Uncompress( unsigned char *pInput, unsigned char *pOutput )
{
	unsigned int actualSize = GetActualSize( pInput );
	if ( !actualSize )
	{
		// unrecognized
		return 0;
	}

	CLzmaDecoderState state;
	if ( LzmaDecodeProperties( &state.Properties, ((lzma_header_t *)pInput)->properties, LZMA_PROPERTIES_SIZE ) != LZMA_RESULT_OK )
	{
		Assert( 0 );
	}
	state.Probs = (CProb *)malloc( LzmaGetNumProbs( &state.Properties ) * sizeof( CProb ) );

	unsigned int lzmaSize = LittleLong( ((lzma_header_t *)pInput)->lzmaSize );

	SizeT inProcessed;
	SizeT outProcessed;
	int result = LzmaDecode( &state, pInput + sizeof( lzma_header_t ), lzmaSize, &inProcessed, pOutput, actualSize, &outProcessed );

	free( state.Probs );

	if ( result != LZMA_RESULT_OK || outProcessed != (SizeT)actualSize )
	{
		Assert( 0 );
		return 0;
	}

	return outProcessed;
}

