[Canderel]

Hi, I have a problem where I have to save the data of a graph into a file. Usually I save the inputs, and regenerate the graph from that, but for backward compatibility I need to be able to save all the data as well. I tried

  TIniFile *F = new TIniFile(filename);
  String Data;
  for (int i = 0; i < Chart->SeriesCount; i++)
    for (int c = 0; c < Chart->Series[i]->Count(); c++)
       Data = Data + IntToStr(Chart->Series[i]->YValues[c].value);
  F->WriteString("GraphData",Chart->Series[i]->Title,Data); 

My problem is that the graph data is longer than 2048 bytes (written in commadelimited string format), so when I read it back, I have lost data. (Looking at the .ini file I can see that the data was written, but when reading it, the string has a 2048 cap).

Then I looked at TIniFile, and saw the WriteBinaryStream method. So I decided I'll use it.

What I want to know is, after defining my stream... ie.

TMemoryStream *Data = new TMemoryStream(); 

How do I add my values (integers) into the Stream?

I tried

   int t = (int)Chart->Series[i]->YValues[c].value;
   Data << t; 

but it doesn't work.

Eventually

  F->WriteBinaryStream("GraphData",Chart->Series[i]->Title,Data); 

will be called to save it, and

  F->ReadBinaryStream("GraphData",Names[i],Data); 

will read it again for me.

Help with how to get it from that stream back to an array of data would also be appreciated.

Thanks for your help.

[Scorpions4ever]

Why not just write the data into a regular file using good ol' fopen(), fprintf(), fclose() etc.

[Canderel]

Well, part of the point is that I want to learn how to use TStreams.

But I used a string in the end... basically, I took the number lets say 40000, and write it down in base 200. Then each of my numbers are 3 characters long, and wrote all the data like that.

      String DataString = "";
      for (int c = 0; c < Chart->Series[i]->Count(); c++)
      {
        double t = Chart->Series[i]->YValues->Value[c];
        int it = (int)t;
        char t1 = it%200;
        char t2 = (it - t1)%(200*200)/200;
        char t3 = (it - t2 - t1*200)%(200*200*200)/200/200;
        // I add 40, because the first 32 chars are control characters
        t1 = t1+40;
        t2 = t2+40;
        t3 = t3+40;
        DataString = DataString + t1 + t2 + t3;
      }


//Decoding  (unsigned was *very* important)
      while (S.Length() >= 3 && !done)
      {
        if (S.Length() > 3)
          S = S.SubString(4,S.Length());
        else done = true;
        long t;
        unsigned char t1 = S[1];
        unsigned char t2 = S[2];
        unsigned char t3 = S[3];

        t = (t1-40)+(t2-40)*256+(t3-40)*256*256;
      }