pdfinsert.pas

wbs43open-src.zip 数字隐藏工具

               CPos:=0;
               lastwritten:=-1;
             end;
           end;
           Percent:=Percent+p;
           if Assigned(FWantCancel) then FWantCancel(self,Cancel);
           if Assigned(FPercentChange) then FPercentChange(self,Percent);
           Application.ProcessMessages;
           tag:='';
           for j:=0 to CPos-lastwritten-2 do Buffer2[j]:=Buffer[j+lastwritten+1];
           newData.Write(Buffer2,CPos-lastwritten-1);
           newData.Write(Insert,8);
           lastwritten:=CPos-1;
           if CPos<BytesRead-1 then Inc(CPos)
           else begin
             for j:=0 to CPos-lastwritten-1 do Buffer2[j]:=Buffer[j+lastwritten+1];
             newData.Write(Buffer2,CPos-lastwritten);
             BytesRead:=Data.Read(Buffer,1024);
             CPos:=0;
             lastwritten:=-1;
           end;
         end;
       end;
       for j:=lastwritten+1 to 1023 do Buffer2[j-lastwritten-1]:=Buffer[j];
       newData.Write(Buffer2,1023-lastwritten);
       if Data.Size>Data.Position then newData.CopyFrom(Data,Data.Size-Data.Position);
       Data.Free;
       Data:=newData;
       Percent:=100;
       if Assigned(FPercentChange) then FPercentChange(self,Percent);
     end
     else Encode:=False;
   end;

   function TPDFInsert.Decode(ResultFile: TDataFile): Boolean;
   var
     S24:            Array[0..2] of Byte;
     Size:           Integer;
     outStrm:        TMemoryStream;
     DataBuffer:     Array[0..1023] of Byte;
     DataWritten:    Integer;
     CarrierBuffer:  Array[0..1023] of Byte;
     CarrierRead:    Integer;
     i,j:            Integer;
     d,c:            Integer;
     val:            Integer;
     inObject:       Boolean;
     tag:            String;
     Cancel:         Boolean;
   begin
     // decode first 3 bits
     Cancel:=False;
     Data.Seek(0,soFromBeginning);
     i:=0;
     d:=0;
     c:=0;
     inObject:=False;
     tag:='';
     CarrierRead:=Data.Read(CarrierBuffer,1024);
     Percent:=0;
     if Assigned(FPercentChange) then FPercentChange(self,Percent);
     while i<3 do begin
       val:=0;
       while (CarrierBuffer[c]<>$d) or inObject do begin
         if not(inObject) then begin
           case Length(tag) of
              0:   if ((CarrierBuffer[c]=Ord('o')) or (CarrierBuffer[c]=Ord('O'))) then tag:='o';
              1:   if ((CarrierBuffer[c]=Ord('b')) or (CarrierBuffer[c]=Ord('B'))) then tag:=tag+'b'
                   else tag:='';
              2:   if ((CarrierBuffer[c]=Ord('j')) or (CarrierBuffer[c]=Ord('J'))) then tag:=tag+'j'
                   else tag:='';
           end;
           if tag='obj' then begin
             inObject:=True;
             tag:='';
           end;
         end
         else begin
           case Length(tag) of
              0:   if ((CarrierBuffer[c]=Ord('e')) or (CarrierBuffer[c]=Ord('E'))) then tag:='e';
              1:   if ((CarrierBuffer[c]=Ord('n')) or (CarrierBuffer[c]=Ord('N'))) then tag:=tag+'n'
                   else tag:='';
              2:   if ((CarrierBuffer[c]=Ord('d')) or (CarrierBuffer[c]=Ord('D'))) then tag:=tag+'d'
                   else tag:='';
              3:   if ((CarrierBuffer[c]=Ord('o')) or (CarrierBuffer[c]=Ord('O'))) then tag:=tag+'o'
                   else tag:='';
              4:   if ((CarrierBuffer[c]=Ord('b')) or (CarrierBuffer[c]=Ord('B'))) then tag:=tag+'b'
                   else tag:='';
              5:   if ((CarrierBuffer[c]=Ord('j')) or (CarrierBuffer[c]=Ord('J'))) then tag:=tag+'j'
                   else tag:='';
           end;
           if tag='endobj' then begin
             inObject:=False;
             tag:='';
           end;
         end;
         if ((c=CarrierRead) and (CarrierRead=1024)) then begin
           CarrierRead:=Data.Read(CarrierBuffer,1024);
           c:=0;
         end
         else Inc(c);
       end;
       for j:=7 downto 0 do begin
         if CarrierBuffer[c-j-1]=$09 then val:=val+(1 shl j);
       end;
       if c<CarrierRead-1 then Inc(c)
       else begin
         CarrierRead:=Data.Read(CarrierBuffer,1024);
         c:=0;
       end;
       S24[d]:=val;
       Inc(DataWritten);
       Inc(d);
       Inc(i);
     end;
     // then decode other data
     Size:=S24[0]+(S24[1] Shl 8)+(S24[2] Shl 16);
     outStrm:=TMemoryStream.Create;
     DataWritten:=0;
     i:=0;
     d:=0;
     while (i<Size) and not(Cancel) do begin
       if (d=1024) then begin
         outStrm.Write(DataBuffer,1024);
         DataWritten:=0;
         d:=0;
       end;
       val:=0;
       val:=0;
       while ((CarrierBuffer[c]<>$d) or inObject) and not(Cancel) do begin
         if not(inObject) then begin
           case Length(tag) of
              0:   if ((CarrierBuffer[c]=Ord('o')) or (CarrierBuffer[c]=Ord('O'))) then tag:='o';
              1:   if ((CarrierBuffer[c]=Ord('b')) or (CarrierBuffer[c]=Ord('B'))) then tag:=tag+'b'
                   else tag:='';
              2:   if ((CarrierBuffer[c]=Ord('j')) or (CarrierBuffer[c]=Ord('J'))) then tag:=tag+'j'
                   else tag:='';
           end;
           if tag='obj' then begin
             inObject:=True;
             tag:='';
           end;
         end
         else begin
           case Length(tag) of
              0:   if ((CarrierBuffer[c]=Ord('e')) or (CarrierBuffer[c]=Ord('E'))) then tag:='e';
              1:   if ((CarrierBuffer[c]=Ord('n')) or (CarrierBuffer[c]=Ord('N'))) then tag:=tag+'n'
                   else tag:='';
              2:   if ((CarrierBuffer[c]=Ord('d')) or (CarrierBuffer[c]=Ord('D'))) then tag:=tag+'d'
                   else tag:='';
              3:   if ((CarrierBuffer[c]=Ord('o')) or (CarrierBuffer[c]=Ord('O'))) then tag:=tag+'o'
                   else tag:='';
              4:   if ((CarrierBuffer[c]=Ord('b')) or (CarrierBuffer[c]=Ord('B'))) then tag:=tag+'b'
                   else tag:='';
              5:   if ((CarrierBuffer[c]=Ord('j')) or (CarrierBuffer[c]=Ord('J'))) then tag:=tag+'j'
                   else tag:='';
           end;
           if tag='endobj' then begin
             inObject:=False;
             tag:='';
           end;
         end;
         if ((c>CarrierRead-2) and (CarrierRead=1024)) then begin
           CarrierRead:=Data.Read(CarrierBuffer,1024);
           c:=0;
           if CarrierRead=0 then cancel:=True;
         end
         else Inc(c);
       end;
       for j:=7 downto 0 do begin
         if CarrierBuffer[c-j-1]=$09 then val:=val+(1 shl j);
       end;
       if c<CarrierRead-1 then Inc(c)
       else begin
         CarrierRead:=Data.Read(CarrierBuffer,1024);
         c:=0;
         if CarrierRead=0 then Cancel:=True;
       end;
       DataBuffer[d]:=val;
       Inc(DataWritten);
       Inc(d);
       Inc(i);
       Percent:=Trunc(i/Size);
       if Assigned(FPercentChange) then FPercentChange(self,Percent);
       if Assigned(FWantCancel) then FWantCancel(self,Cancel);
       Application.ProcessMessages;
     end;
     outStrm.Write(DataBuffer,DataWritten);
     ResultFile.LoadFromStream(outStrm);
     outStrm.Free;
     Percent:=100;
     if Assigned(FPercentChange) then FPercentChange(self,Percent);
     Decode:=True;
   end;

   function TPDFInsert.isUsable: String;
   var
     id:      Array[0..3] of Byte;
     idStr:   String;
     i:       Byte;
   begin
     Data.Seek(0,soFromBeginning);
     Data.Read(id,4);
     idStr:='';
     for i:=0 to 3 do begin
       idStr:=idStr+Chr(id[i]);
     end;
     if idStr='%PDF' then isUsable:='OK'
     else isUsable:=ml.GetCodeString('PDFInsert',1);
   end;

end.