unpack.cpp

7Zip软件实现： 七种编码格式的压缩与解压缩功能。

    }
  Array<byte> VMCode(Length);
  for (int I=0;I<Length;I++)
  {
    int Ch=PPM.DecodeChar();
    if (Ch==-1)
      return(false);
    VMCode[I]=Ch;
  }
  return(AddVMCode(FirstByte,&VMCode[0],Length));
}


bool Unpack::AddVMCode(unsigned int FirstByte,byte *Code,int CodeSize)
{
  BitInput Inp;
  Inp.InitBitInput();
  memcpy(Inp.InBuf,Code,Min(BitInput::MAX_SIZE,CodeSize));
  VM.Init();

  uint FiltPos;
  if (FirstByte & 0x80)
  {
    FiltPos=RarVM::ReadData(Inp);
    if (FiltPos==0)
      InitFilters();
    else
      FiltPos--;
  }
  else
    FiltPos=LastFilter;
  if (FiltPos>Filters.Size() || FiltPos>OldFilterLengths.Size())
    return(false);
  LastFilter=FiltPos;
  bool NewFilter=(FiltPos==Filters.Size());

  UnpackFilter *Filter;
  if (NewFilter)
  {
    Filters.Add(1);
    Filters[Filters.Size()-1]=Filter=new UnpackFilter;
    OldFilterLengths.Add(1);
    Filter->ExecCount=0;
  }
  else
  {
    Filter=Filters[FiltPos];
    Filter->ExecCount++;
  }

  UnpackFilter *StackFilter=new UnpackFilter;

  int EmptyCount=0;
  for (int I=0;I<PrgStack.Size();I++)
  {
    PrgStack[I-EmptyCount]=PrgStack[I];
    if (PrgStack[I]==NULL)
      EmptyCount++;
    if (EmptyCount>0)
      PrgStack[I]=NULL;
  }
  if (EmptyCount==0)
  {
    PrgStack.Add(1);
    EmptyCount=1;
  }
  int StackPos=PrgStack.Size()-EmptyCount;
  PrgStack[StackPos]=StackFilter;
  StackFilter->ExecCount=Filter->ExecCount;
 
  uint BlockStart=RarVM::ReadData(Inp);
  if (FirstByte & 0x40)
    BlockStart+=258;
  StackFilter->BlockStart=(BlockStart+UnpPtr)&MAXWINMASK;
  if (FirstByte & 0x20)
    StackFilter->BlockLength=RarVM::ReadData(Inp);
  else
    StackFilter->BlockLength=FiltPos<OldFilterLengths.Size() ? OldFilterLengths[FiltPos]:0;
  StackFilter->NextWindow=WrPtr!=UnpPtr && ((WrPtr-UnpPtr)&MAXWINMASK)<=BlockStart;

//  DebugLog("\nNextWindow: UnpPtr=%08x WrPtr=%08x BlockStart=%08x",UnpPtr,WrPtr,BlockStart);

  OldFilterLengths[FiltPos]=StackFilter->BlockLength;

  memset(StackFilter->Prg.InitR,0,sizeof(StackFilter->Prg.InitR));
  StackFilter->Prg.InitR[3]=VM_GLOBALMEMADDR;
  StackFilter->Prg.InitR[4]=StackFilter->BlockLength;
  StackFilter->Prg.InitR[5]=StackFilter->ExecCount;
  if (FirstByte & 0x10)
  {
    unsigned int InitMask=Inp.fgetbits()>>9;
    Inp.faddbits(7);
    for (int I=0;I<7;I++)
      if (InitMask & (1<<I))
        StackFilter->Prg.InitR[I]=RarVM::ReadData(Inp);
  }
  if (NewFilter)
  {
    uint VMCodeSize=RarVM::ReadData(Inp);
    if (VMCodeSize>=0x10000 || VMCodeSize==0)
      return(false);
    Array<byte> VMCode(VMCodeSize);
    for (int I=0;I<VMCodeSize;I++)
    {
      VMCode[I]=Inp.fgetbits()>>8;
      Inp.faddbits(8);
    }
    VM.Prepare(&VMCode[0],VMCodeSize,&Filter->Prg);
  }
  StackFilter->Prg.AltCmd=&Filter->Prg.Cmd[0];
  StackFilter->Prg.CmdCount=Filter->Prg.CmdCount;

  int StaticDataSize=Filter->Prg.StaticData.Size();
  if (StaticDataSize>0 && StaticDataSize<VM_GLOBALMEMSIZE)
  {
    StackFilter->Prg.StaticData.Add(StaticDataSize);
    memcpy(&StackFilter->Prg.StaticData[0],&Filter->Prg.StaticData[0],StaticDataSize);
  }

  if (StackFilter->Prg.GlobalData.Size()<VM_FIXEDGLOBALSIZE)
  {
    StackFilter->Prg.GlobalData.Reset();
    StackFilter->Prg.GlobalData.Add(VM_FIXEDGLOBALSIZE);
  }
  byte *GlobalData=&StackFilter->Prg.GlobalData[0];
  for (int I=0;I<7;I++)
    VM.SetValue((uint *)&GlobalData[I*4],StackFilter->Prg.InitR[I]);
  VM.SetValue((uint *)&GlobalData[0x1c],StackFilter->BlockLength);
  VM.SetValue((uint *)&GlobalData[0x20],0);
  VM.SetValue((uint *)&GlobalData[0x2c],StackFilter->ExecCount);
  memset(&GlobalData[0x30],0,16);

  if (FirstByte & 8)
  {
    uint DataSize=RarVM::ReadData(Inp);
    if (DataSize>=0x10000)
      return(false);
    unsigned int CurSize=StackFilter->Prg.GlobalData.Size();
    if (CurSize<DataSize+VM_FIXEDGLOBALSIZE)
      StackFilter->Prg.GlobalData.Add(DataSize+VM_FIXEDGLOBALSIZE-CurSize);
    byte *GlobalData=&StackFilter->Prg.GlobalData[VM_FIXEDGLOBALSIZE];
    for (int I=0;I<DataSize;I++)
    {
      GlobalData[I]=Inp.fgetbits()>>8;
      Inp.faddbits(8);
    }
  }
  return(true);
}


bool Unpack::UnpReadBuf()
{
  int DataSize=ReadTop-InAddr;
  if (DataSize<0)
    return(false);
  if (InAddr>BitInput::MAX_SIZE/2)
  {
    if (DataSize>0)
      memmove(InBuf,InBuf+InAddr,DataSize);
    InAddr=0;
    ReadTop=DataSize;
  }
  else
    DataSize=ReadTop;
  int ReadCode=UnpIO->UnpRead(InBuf+DataSize,(BitInput::MAX_SIZE-DataSize)&~0xf);
  if (ReadCode>0)
    ReadTop+=ReadCode;
  ReadBorder=ReadTop-30;
  return(ReadCode!=-1);
}


void Unpack::UnpWriteBuf()
{
  unsigned int WrittenBorder=WrPtr;
  unsigned int WriteSize=(UnpPtr-WrittenBorder)&MAXWINMASK;
  for (int I=0;I<PrgStack.Size();I++)
  {
    UnpackFilter *flt=PrgStack[I];
    if (flt==NULL)
      continue;
    if (flt->NextWindow)
    {
      flt->NextWindow=false;
      continue;
    }
    unsigned int BlockStart=flt->BlockStart;
    unsigned int BlockLength=flt->BlockLength;
    if (((BlockStart-WrittenBorder)&MAXWINMASK)<WriteSize)
    {
      if (WrittenBorder!=BlockStart)
      {
        UnpWriteArea(WrittenBorder,BlockStart);
        WrittenBorder=BlockStart;
        WriteSize=(UnpPtr-WrittenBorder)&MAXWINMASK;
      }
      if (BlockLength<=WriteSize)
      {
        unsigned int BlockEnd=(BlockStart+BlockLength)&MAXWINMASK;
        if (BlockStart<BlockEnd || BlockEnd==0)
          VM.SetMemory(0,Window+BlockStart,BlockLength);
        else
        {
          unsigned int FirstPartLength=MAXWINSIZE-BlockStart;
          VM.SetMemory(0,Window+BlockStart,FirstPartLength);
          VM.SetMemory(FirstPartLength,Window,BlockEnd);
        }
        VM_PreparedProgram *Prg=&flt->Prg;
        ExecuteCode(Prg);

        byte *FilteredData=Prg->FilteredData;
        unsigned int FilteredDataSize=Prg->FilteredDataSize;

        delete PrgStack[I];
        PrgStack[I]=NULL;
        while (I+1<PrgStack.Size())
        {
          UnpackFilter *NextFilter=PrgStack[I+1];
          if (NextFilter==NULL || NextFilter->BlockStart!=BlockStart ||
              NextFilter->BlockLength!=FilteredDataSize || NextFilter->NextWindow)
            break;
          VM.SetMemory(0,FilteredData,FilteredDataSize);
          VM_PreparedProgram *NextPrg=&PrgStack[I+1]->Prg;
          ExecuteCode(NextPrg);
          FilteredData=NextPrg->FilteredData;
          FilteredDataSize=NextPrg->FilteredDataSize;
          I++;
          delete PrgStack[I];
          PrgStack[I]=NULL;
        }
        UnpIO->UnpWrite(FilteredData,FilteredDataSize);
        UnpSomeRead=true;
        WrittenFileSize+=FilteredDataSize;
        WrittenBorder=BlockEnd;
        WriteSize=(UnpPtr-WrittenBorder)&MAXWINMASK;
      }
      else
      {
        for (int J=I;J<PrgStack.Size();J++)
        {
          UnpackFilter *flt=PrgStack[J];
          if (flt!=NULL && flt->NextWindow)
            flt->NextWindow=false;
        }
        WrPtr=WrittenBorder;
        return;
      }
    }
  }
      
  UnpWriteArea(WrittenBorder,UnpPtr);
  WrPtr=UnpPtr;
}


void Unpack::ExecuteCode(VM_PreparedProgram *Prg)
{
  if (Prg->GlobalData.Size()>0)
  {
    Prg->InitR[6]=int64to32(WrittenFileSize);
    VM.SetValue((uint *)&Prg->GlobalData[0x24],int64to32(WrittenFileSize));
    VM.SetValue((uint *)&Prg->GlobalData[0x28],int64to32(WrittenFileSize>>32));
    VM.Execute(Prg);
  }
}


void Unpack::UnpWriteArea(unsigned int StartPtr,unsigned int EndPtr)
{
  if (EndPtr!=StartPtr)
    UnpSomeRead=true;
  if (EndPtr<StartPtr)
  {
    UnpWriteData(&Window[StartPtr],-StartPtr & MAXWINMASK);
    UnpWriteData(Window,EndPtr);
    UnpAllBuf=true;
  }
  else
    UnpWriteData(&Window[StartPtr],EndPtr-StartPtr);
}


void Unpack::UnpWriteData(byte *Data,int Size)
{
  if (WrittenFileSize>=DestUnpSize)
    return;
  int WriteSize=Size;
  Int64 LeftToWrite=DestUnpSize-WrittenFileSize;
  if (WriteSize>LeftToWrite)
    WriteSize=int64to32(LeftToWrite);
  UnpIO->UnpWrite(Data,WriteSize);
  WrittenFileSize+=Size;
}


bool Unpack::ReadTables()
{
  byte BitLength[BC];
  unsigned char Table[HUFF_TABLE_SIZE];
  if (InAddr>ReadTop-25)
    if (!UnpReadBuf())
      return(false);
  faddbits((8-InBit)&7);
  unsigned int BitField=fgetbits();
  if (BitField & 0x8000)
  {
    UnpBlockType=BLOCK_PPM;
    return(PPM.DecodeInit(this,PPMEscChar));
  }
  UnpBlockType=BLOCK_LZ;
  
  PrevLowDist=0;
  LowDistRepCount=0;

  if (!(BitField & 0x4000))
    memset(UnpOldTable,0,sizeof(UnpOldTable));
  faddbits(2);

  for (int I=0;I<BC;I++)
  {
    int Length=(byte)(fgetbits() >> 12);
    faddbits(4);
    if (Length==15)
    {
      int ZeroCount=(byte)(fgetbits() >> 12);
      faddbits(4);
      if (ZeroCount==0)
        BitLength[I]=15;
      else
      {
        ZeroCount+=2;
        while (ZeroCount-- > 0 && I<sizeof(BitLength)/sizeof(BitLength[0]))
          BitLength[I++]=0;
        I--;
      }
    }
    else
      BitLength[I]=Length;
  }
  MakeDecodeTables(BitLength,(struct Decode *)&BD,BC);

  const int TableSize=HUFF_TABLE_SIZE;
  for (int I=0;I<TableSize;)
  {
    if (InAddr>ReadTop-5)
      if (!UnpReadBuf())
        return(false);
    int Number=DecodeNumber((struct Decode *)&BD);
    if (Number<16)
    {
      Table[I]=(Number+UnpOldTable[I]) & 0xf;
      I++;
    }
    else
      if (Number<18)
      {
        int N;
        if (Number==16)
        {
          N=(fgetbits() >> 13)+3;
          faddbits(3);
        }
        else
        {
          N=(fgetbits() >> 9)+11;
          faddbits(7);
        }
        while (N-- > 0 && I<TableSize)
        {
          Table[I]=Table[I-1];
          I++;
        }
      }
      else
      {
        int N;
        if (Number==18)
        {
          N=(fgetbits() >> 13)+3;
          faddbits(3);
        }
        else
        {
          N=(fgetbits() >> 9)+11;
          faddbits(7);
        }
        while (N-- > 0 && I<TableSize)
          Table[I++]=0;
      }
  }
  TablesRead=true;
  if (InAddr>ReadTop)
    return(false);
  MakeDecodeTables(&Table[0],(struct Decode *)&LD,NC);
  MakeDecodeTables(&Table[NC],(struct Decode *)&DD,DC);
  MakeDecodeTables(&Table[NC+DC],(struct Decode *)&LDD,LDC);
  MakeDecodeTables(&Table[NC+DC+LDC],(struct Decode *)&RD,RC);
  memcpy(UnpOldTable,Table,sizeof(UnpOldTable));
  return(true);
}


void Unpack::UnpInitData(int Solid)
{
  if (!Solid)
  {
    TablesRead=false;
    memset(OldDist,0,sizeof(OldDist));
    OldDistPtr=0;
    LastDist=LastLength=0;
//    memset(Window,0,MAXWINSIZE);
    memset(UnpOldTable,0,sizeof(UnpOldTable));
    UnpPtr=WrPtr=0;
    PPMEscChar=2;

    InitFilters();
  }
  InitBitInput();
  PPMError=false;
  WrittenFileSize=0;
  ReadTop=0;
  ReadBorder=0;
#ifndef SFX_MODULE
  // Igor Pavlov
  // UnpInitData20(Solid);
#endif
}


void Unpack::InitFilters()
{
  OldFilterLengths.Reset();
  LastFilter=0;

  for (int I=0;I<Filters.Size();I++)
    delete Filters[I];
  Filters.Reset();
  for (int I=0;I<PrgStack.Size();I++)
    delete PrgStack[I];
  PrgStack.Reset();
}


void Unpack::MakeDecodeTables(unsigned char *LenTab,struct Decode *Dec,int Size)
{
  int LenCount[16],TmpPos[16],I;
  long M,N;
  memset(LenCount,0,sizeof(LenCount));
  memset(Dec->DecodeNum,0,Size*sizeof(*Dec->DecodeNum));
  for (I=0;I<Size;I++)
    LenCount[LenTab[I] & 0xF]++;

  LenCount[0]=0;
  for (TmpPos[0]=Dec->DecodePos[0]=Dec->DecodeLen[0]=0,N=0,I=1;I<16;I++)
  {
    N=2*(N+LenCount[I]);
    M=N<<(15-I);
    if (M>0xFFFF)
      M=0xFFFF;
    Dec->DecodeLen[I]=(unsigned int)M;
    TmpPos[I]=Dec->DecodePos[I]=Dec->DecodePos[I-1]+LenCount[I-1];
  }

  for (I=0;I<Size;I++)
    if (LenTab[I]!=0)
      Dec->DecodeNum[TmpPos[LenTab[I] & 0xF]++]=I;
  Dec->MaxNum=Size;
}