rarvm.cpp

我把unrar的代码整理成vc工程了

  }
}


void RarVM::SetMemory(unsigned int Pos,byte *Data,unsigned int DataSize)
{
  if (Pos<VM_MEMSIZE && Data!=Mem+Pos)
    memmove(Mem+Pos,Data,Min(DataSize,VM_MEMSIZE-Pos));
}


#ifdef VM_OPTIMIZE
void RarVM::Optimize(VM_PreparedProgram *Prg)
{
  VM_PreparedCommand *Code=&Prg->Cmd[0];
  int CodeSize=Prg->CmdCount;

  for (int I=0;I<CodeSize;I++)
  {
    VM_PreparedCommand *Cmd=Code+I;

    // Replace universal opcodes with faster byte or word only processing
    // opcodes.
    switch(Cmd->OpCode)
    {
      case VM_MOV:
        Cmd->OpCode=Cmd->ByteMode ? VM_MOVB:VM_MOVD;
        continue;
      case VM_CMP:
        Cmd->OpCode=Cmd->ByteMode ? VM_CMPB:VM_CMPD;
        continue;
    }
    if ((VM_CmdFlags[Cmd->OpCode] & VMCF_CHFLAGS)==0)
      continue;

    // If we do not have jump commands between the current operation
    // and next command which will modify processor flags, we can replace
    // the current command with faster version which does not need to
    // modify flags.
    bool FlagsRequired=false;
    for (int J=I+1;J<CodeSize;J++)
    {
      int Flags=VM_CmdFlags[Code[J].OpCode];
      if (Flags & (VMCF_JUMP|VMCF_PROC|VMCF_USEFLAGS))
      {
        FlagsRequired=true;
        break;
      }
      if (Flags & VMCF_CHFLAGS)
        break;
    }

    // Below we'll replace universal opcodes with faster byte or word only 
    // processing opcodes, which also do not modify processor flags to
    // provide better performance.
    if (FlagsRequired)
      continue;
    switch(Cmd->OpCode)
    {
      case VM_ADD:
        Cmd->OpCode=Cmd->ByteMode ? VM_ADDB:VM_ADDD;
        continue;
      case VM_SUB:
        Cmd->OpCode=Cmd->ByteMode ? VM_SUBB:VM_SUBD;
        continue;
      case VM_INC:
        Cmd->OpCode=Cmd->ByteMode ? VM_INCB:VM_INCD;
        continue;
      case VM_DEC:
        Cmd->OpCode=Cmd->ByteMode ? VM_DECB:VM_DECD;
        continue;
      case VM_NEG:
        Cmd->OpCode=Cmd->ByteMode ? VM_NEGB:VM_NEGD;
        continue;
    }
  }
}
#endif


#ifdef VM_STANDARDFILTERS
VM_StandardFilters RarVM::IsStandardFilter(byte *Code,int CodeSize)
{
  struct StandardFilterSignature
  {
    int Length;
    uint CRC;
    VM_StandardFilters Type;
  } static StdList[]={
    53, 0xad576887, VMSF_E8,
    57, 0x3cd7e57e, VMSF_E8E9,
   120, 0x3769893f, VMSF_ITANIUM,
    29, 0x0e06077d, VMSF_DELTA,
   149, 0x1c2c5dc8, VMSF_RGB,
   216, 0xbc85e701, VMSF_AUDIO,
    40, 0x46b9c560, VMSF_UPCASE
  };
  uint CodeCRC=CRC(0xffffffff,Code,CodeSize)^0xffffffff;
  for (int I=0;I<sizeof(StdList)/sizeof(StdList[0]);I++)
    if (StdList[I].CRC==CodeCRC && StdList[I].Length==CodeSize)
      return(StdList[I].Type);
  return(VMSF_NONE);
}


void RarVM::ExecuteStandardFilter(VM_StandardFilters FilterType)
{
  switch(FilterType)
  {
    case VMSF_E8:
    case VMSF_E8E9:
      {
        byte *Data=Mem;
        int DataSize=R[4];
        uint FileOffset=R[6];

        if (DataSize>=VM_GLOBALMEMADDR || DataSize<4)
          break;

        const int FileSize=0x1000000;
        byte CmpByte2=FilterType==VMSF_E8E9 ? 0xe9:0xe8;
        for (int CurPos=0;CurPos<DataSize-4;)
        {
          byte CurByte=*(Data++);
          CurPos++;
          if (CurByte==0xe8 || CurByte==CmpByte2)
          {
#ifdef PRESENT_INT32
            sint32 Offset=CurPos+FileOffset;
            sint32 Addr=GET_VALUE(false,Data);
            if (Addr<0)
            {
              if (Addr+Offset>=0)
                SET_VALUE(false,Data,Addr+FileSize);
            }
            else
              if (Addr<FileSize)
                SET_VALUE(false,Data,Addr-Offset);
#else
            long Offset=CurPos+FileOffset;
            long Addr=GET_VALUE(false,Data);
            if ((Addr & 0x80000000)!=0)
            {
              if (((Addr+Offset) & 0x80000000)==0)
                SET_VALUE(false,Data,Addr+FileSize);
            }
            else 
              if (((Addr-FileSize) & 0x80000000)!=0)
                SET_VALUE(false,Data,Addr-Offset);
#endif
            Data+=4;
            CurPos+=4;
          }
        }
      }
      break;
    case VMSF_ITANIUM:
      {
        byte *Data=Mem;
        int DataSize=R[4];
        uint FileOffset=R[6];

        if (DataSize>=VM_GLOBALMEMADDR || DataSize<21)
          break;

        int CurPos=0;

        FileOffset>>=4;

        while (CurPos<DataSize-21)
        {
          int Byte=(Data[0]&0x1f)-0x10;
          if (Byte>=0)
          {
            static byte Masks[16]={4,4,6,6,0,0,7,7,4,4,0,0,4,4,0,0};
            byte CmdMask=Masks[Byte];
            if (CmdMask!=0)
              for (int I=0;I<=2;I++)
                if (CmdMask & (1<<I))
                {
                  int StartPos=I*41+5;
                  int OpType=FilterItanium_GetBits(Data,StartPos+37,4);
                  if (OpType==5)
                  {
                    int Offset=FilterItanium_GetBits(Data,StartPos+13,20);
                    FilterItanium_SetBits(Data,(Offset-FileOffset)&0xfffff,StartPos+13,20);
                  }
                }
          }
          Data+=16;
          CurPos+=16;
          FileOffset++;
        }
      }
      break;
    case VMSF_DELTA:
      {
        int DataSize=R[4],Channels=R[0],SrcPos=0,Border=DataSize*2;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;

        // Bytes from same channels are grouped to continual data blocks,
        // so we need to place them back to their interleaving positions.
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          byte PrevByte=0;
          for (int DestPos=DataSize+CurChannel;DestPos<Border;DestPos+=Channels)
            Mem[DestPos]=(PrevByte-=Mem[SrcPos++]);
        }
      }
      break;
    case VMSF_RGB:
      {
        int DataSize=R[4],Width=R[0]-3,PosR=R[1];
        byte *SrcData=Mem,*DestData=SrcData+DataSize;
        const int Channels=3;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2 || PosR<0)
          break;
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          unsigned int PrevByte=0;

          for (int I=CurChannel;I<DataSize;I+=Channels)
          {
            unsigned int Predicted;
            int UpperPos=I-Width;
            if (UpperPos>=3)
            {
              byte *UpperData=DestData+UpperPos;
              unsigned int UpperByte=*UpperData;
              unsigned int UpperLeftByte=*(UpperData-3);
              Predicted=PrevByte+UpperByte-UpperLeftByte;
              int pa=abs((int)(Predicted-PrevByte));
              int pb=abs((int)(Predicted-UpperByte));
              int pc=abs((int)(Predicted-UpperLeftByte));
              if (pa<=pb && pa<=pc)
                Predicted=PrevByte;
              else
                if (pb<=pc)
                  Predicted=UpperByte;
                else
                  Predicted=UpperLeftByte;
            }
            else
              Predicted=PrevByte;
            DestData[I]=PrevByte=(byte)(Predicted-*(SrcData++));
          }
        }
        for (int I=PosR,Border=DataSize-2;I<Border;I+=3)
        {
          byte G=DestData[I+1];
          DestData[I]+=G;
          DestData[I+2]+=G;
        }
      }
      break;
    case VMSF_AUDIO:
      {
        int DataSize=R[4],Channels=R[0];
        byte *SrcData=Mem,*DestData=SrcData+DataSize;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          unsigned int PrevByte=0,PrevDelta=0,Dif[7];
          int D1=0,D2=0,D3;
          int K1=0,K2=0,K3=0;
          memset(Dif,0,sizeof(Dif));

          for (int I=CurChannel,ByteCount=0;I<DataSize;I+=Channels,ByteCount++)
          {
            D3=D2;
            D2=PrevDelta-D1;
            D1=PrevDelta;

            unsigned int Predicted=8*PrevByte+K1*D1+K2*D2+K3*D3;
            Predicted=(Predicted>>3) & 0xff;

            unsigned int CurByte=*(SrcData++);

            Predicted-=CurByte;
            DestData[I]=Predicted;
            PrevDelta=(signed char)(Predicted-PrevByte);
            PrevByte=Predicted;

            int D=((signed char)CurByte)<<3;

            Dif[0]+=abs(D);
            Dif[1]+=abs(D-D1);
            Dif[2]+=abs(D+D1);
            Dif[3]+=abs(D-D2);
            Dif[4]+=abs(D+D2);
            Dif[5]+=abs(D-D3);
            Dif[6]+=abs(D+D3);

            if ((ByteCount & 0x1f)==0)
            {
              unsigned int MinDif=Dif[0],NumMinDif=0;
              Dif[0]=0;
              for (int J=1;J<sizeof(Dif)/sizeof(Dif[0]);J++)
              {
                if (Dif[J]<MinDif)
                {
                  MinDif=Dif[J];
                  NumMinDif=J;
                }
                Dif[J]=0;
              }
              switch(NumMinDif)
              {
                case 1: if (K1>=-16) K1--; break;
                case 2: if (K1 < 16) K1++; break;
                case 3: if (K2>=-16) K2--; break;
                case 4: if (K2 < 16) K2++; break;
                case 5: if (K3>=-16) K3--; break;
                case 6: if (K3 < 16) K3++; break;
              }
            }
          }
        }
      }
      break;
    case VMSF_UPCASE:
      {
        int DataSize=R[4],SrcPos=0,DestPos=DataSize;
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        while (SrcPos<DataSize)
        {
          byte CurByte=Mem[SrcPos++];
          if (CurByte==2 && (CurByte=Mem[SrcPos++])!=2)
            CurByte-=32;
          Mem[DestPos++]=CurByte;
        }
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x1c],DestPos-DataSize);
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
      }
      break;
  }
}


unsigned int RarVM::FilterItanium_GetBits(byte *Data,int BitPos,int BitCount)
{
  int InAddr=BitPos/8;
  int InBit=BitPos&7;
  unsigned int BitField=(uint)Data[InAddr++];
  BitField|=(uint)Data[InAddr++] << 8;
  BitField|=(uint)Data[InAddr++] << 16;
  BitField|=(uint)Data[InAddr] << 24;
  BitField >>= InBit;
  return(BitField & (0xffffffff>>(32-BitCount)));
}


void RarVM::FilterItanium_SetBits(byte *Data,unsigned int BitField,int BitPos,
                                  int BitCount)
{
  int InAddr=BitPos/8;
  int InBit=BitPos&7;
  unsigned int AndMask=0xffffffff>>(32-BitCount);
  AndMask=~(AndMask<<InBit);

  BitField<<=InBit;

  for (int I=0;I<4;I++)
  {
    Data[InAddr+I]&=AndMask;
    Data[InAddr+I]|=BitField;
    AndMask=(AndMask>>8)|0xff000000;
    BitField>>=8;
  }
}
#endif