unit ScannerKeywordsJumpTableGenerator;



interface



uses SysUtils, IniFiles, Classes;



procedure IdentifierProc;

procedure InitKeywords;



implementation



uses Dialogs, Scanner, Tokens, SearchCode, HashExplorer, ComCtrls, Math, GeneratorCommon;



type

  PKeywordArray = ^TKeywordArray;

  TKeywordArray = record

    Hash: Byte;

    Node: TTreeNode;

    Lengths: array of TTokenType;

    Keywords: array of TTokenType;

  end;



  PKeywordPair = ^TKeywordPair;

  TKeywordPair = record

    Hash: Byte;

    Keyword: TTokenType;

  end;



var

  Hashes: array of TKeywordArray;



procedure IdentifierProc;

begin

end;



procedure AddEntry(Hash: Byte; TokenType: TTokenType);

var i: Integer;



  procedure Add;

  begin

    SetLength(Hashes[i].Keywords, Length(Hashes[i].Keywords) + 1);

    Hashes[i].Keywords[High(Hashes[i].Keywords)] := TokenType;

    

    HashEx.TreeView.Items.AddChild(Hashes[i].Node, TokenName[TokenType]);

    Hashes[i].Node.Expand(False);

  end;



begin

  for i := 0 to High(Hashes) do

    if Hashes[i].Hash = Hash then

      begin

        Add;

        Exit;

      end;



  i := Length(Hashes);

  SetLength(Hashes, i + 1);

  Hashes[i].Hash := Hash;

  Hashes[i].Node := HashEx.TreeView.Items.AddChild(nil, IntToHex(Hash, 2));

  Add;

end;



function Compare(Item1, Item2: Pointer): Integer;

begin

  Result := PKeywordPair(Item1).Hash -  PKeywordPair(Item2).Hash;

end;



procedure InitKeywords;

var

  i: TTokenType;

  Hash: Byte;

  Keyword: PAnsiChar;

  x, y,Len,z, lenlow, lenhigh: Integer;

  Test: TList;

  Pair: PKeywordPair;



  procedure FindHash;

  var i: Integer;

  begin

    for i := 0 to High(Hashes) do

      if Hashes[i].Hash = x then

        begin

          y := i;

          Exit;

        end;

    y := -1;

  end;

begin

  Test := TList.Create;



  lenlow := High(Integer);

  lenhigh := Low(Integer);



  for i := ttGlobals to High(TTokenType) do

    begin

      Hash := 0;

      Keyword := TokenName[i];

      lenlow := Min(lenlow, StrLen(Keyword));

      lenhigh := Max(lenhigh, StrLen(Keyword));



      {$RANGECHECKS OFF}

      {$OVERFLOWCHECKS OFF}

      while Keyword^ <> #0 do

        begin

          Hash := Hash + Byte(Keyword^);


          Inc(Keyword);

        end;



      {$OVERFLOWCHECKS ON}

      {$RANGECHECKS ON}



      New(Pair);

      Pair.Hash := Hash;

      Pair.Keyword := i;





      Test.Add(Pair);

    end;



  Test.Sort(@Compare);



  for x := 0 to Test.Count - 1 do

    begin

      AddEntry(PKeywordPair(Test[x]).Hash, PKeywordPair(Test[x]).Keyword);

      Dispose(Test[x]);

    end;



  SearchForm.Memo.Lines.Add('  sub edx, ' + IntToStr(lenlow));

  SearchForm.Memo.Lines.Add('  cmp edx, ' + IntToStr(lenhigh - lenlow));

  SearchForm.Memo.Lines.Add('  jbe @CheckKeywords');

  SearchForm.Memo.Lines.Add('  ret');

  SearchForm.Memo.Lines.Add('');

  SearchForm.Memo.Lines.Add('@CheckKeywords:');

  SearchForm.Memo.Lines.Add('  jmp dword ptr [@JumpTable + eax * 4]');

  SearchForm.Memo.Lines.Add('');

  SearchForm.Memo.Lines.Add('@Return:');

  SearchForm.Memo.Lines.Add('  ret');

  SearchForm.Memo.Lines.Add('');

  SearchForm.Memo.Lines.Add('@JumpTable:');



  for x := 0 to 255 do

    begin

      FindHash;

      if y = -1 then

        SearchForm.Memo.Lines.Add(' dd @Return')

      else

        SearchForm.Memo.Lines.Add(' dd @Check' + IntToHex(x, 2));

    end;



  // Generate length checks



  for x := 0 to High(Hashes) do

    begin

      SearchForm.Memo.Lines.Add('');

      SearchForm.Memo.Lines.Add('@Check' + IntToHex(Hashes[x].Hash, 2) + ':');



      Test.Clear;



      for y := 0 to High(Hashes[x].Keywords) do

        begin

          len := StrLen(TokenName[Hashes[x].Keywords[y]]);

          if Test.IndexOf(Pointer(len)) = -1 then

            Test.Add(Pointer(len));

        end;



      for y := 0 to Test.Count -1 do

        begin

          SearchForm.Memo.Lines.Add('  cmp edx, ' + IntToStr(Integer(Test[y]) - lenlow));

          SearchForm.Memo.Lines.Add('  je @Compare' + IntToHex(Hashes[x].Hash, 2) + '_' + IntToStr(Integer(Test[y]))+'_0');

        end;



      SearchForm.Memo.Lines.Add('  ret');

    end;



  // Full comparasions

  

  for x := 0 to High(Hashes) do

    begin

      Test.Clear;



      for y := 0 to High(Hashes[x].Keywords) do

        begin

          len := StrLen(TokenName[Hashes[x].Keywords[y]]);

          if Test.IndexOf(Pointer(len)) = -1 then

            Test.Add(Pointer(len));

        end;



      SearchForm.Memo.Lines.Add(' ');



      for z := 0 to Test.Count -1 do

        begin

          len := 0;

          

          for y := 0 to High(Hashes[x].Keywords) do

            if StrLen(TokenName[Hashes[x].Keywords[y]]) = Cardinal(Test[z]) then

              Inc(len);



          SearchForm.Memo.Lines.Add('@Compare' + IntToHex(Hashes[x].Hash, 2) + '_' + IntToStr(Integer(Test[z]))+'_' + IntToStr(len)+':');

        end;



      SearchForm.Memo.Lines.Add('  ret');





      for z := 0 to Test.Count -1 do

        begin

          len := 0;

          for y := 0 to High(Hashes[x].Keywords) do

            if StrLen(TokenName[Hashes[x].Keywords[y]]) = Cardinal(Test[z]) then

              begin

                SearchForm.Memo.Lines.Add('');

                SearchForm.Memo.Lines.Add('@Compare' + IntToHex(Hashes[x].Hash, 2) + '_' + IntToStr(Integer(Test[z]))+'_' + IntToStr(len)+':');



                CompareKeyword(TokenName[Hashes[x].Keywords[y]], 'ecx', '@Compare' + IntToHex(Hashes[x].Hash, 2) + '_' + IntToStr(Integer(Test[z]))+'_' + IntToStr(len + 1));



                SearchForm.Memo.Lines.Add('');

                SearchForm.Memo.Lines.Add('  mov [Token.Token], tt' + TokenName[Hashes[x].Keywords[y]]);

                SearchForm.Memo.Lines.Add('  ret');



                Inc(len);

              end;

          end;

        SearchForm.Memo.Lines.Add('');

    end;



  SearchForm.Show;

  HashExplorer.HashEx.Show;

  Test.Free;

end;







end.