Author: Pieter Valentijn

How to get a lot of files in one stream 
And get it back to :)

Answer:

Some times i want to Have multiple files in a stream couse then i dont have to send 
a lot of files but just one . 

So heres a little code sniped to get it in and out again. 

1   procedure TForm1.ThisISHowIPutFilesIn;
2   var
3     ABigFileStream, SomeSmallFiles: TMemoryStream;
4   
5   begin
6     ABigFileStream := TMemoryStream.Create;
7     try
8       SomeSmallFiles := TMemoryStream.Create;
9       try
10        SomeSmallFiles.LoadFromFile('C:\SomeSmalFile1.txt');
11        AddToStream(SomeSmallFiles, ABigFileStream);
12        SomeSmallFiles.LoadFromFile('C:\SomeSmalFile2.txt');
13        AddToStream(SomeSmallFiles, ABigFileStream);
14        // enz
15      finally
16        SomeSmallFiles.Free;
17      end;
18      ABigFileStream.SaveToFile('C:\MrBig.DDD')
19    finally
20      ABigFileStream.free;
21    end;
22  end;
23  
24  procedure TForm1.ThisISHowIGetStufOut;
25  var
26    ABigFileStream, SomeSmallFiles: TMemoryStream;
27  
28  begin
29    ABigFileStream := TMemoryStream.Create;
30    try
31      ABigFileStream.LoadFromFile('C:\MrBig.DDD');
32      SomeSmallFiles := TMemoryStream.Create;
33      try
34        GetFromStream(ABigFileStream, SomeSmallFiles, 0);
35        SomeSmallFiles.SaveToFile('C:\SomeSmalFile1.txt');
36        GetFromStream(ABigFileStream, SomeSmallFiles, 1);
37        SomeSmallFiles.SaveToFile('C:\SomeSmalFile2.txt');
38        // enz
39      finally
40        SomeSmallFiles.Free;
41      end;
42    finally
43      ABigFileStream.free;
44    end;
45  end;
46  
47  procedure TForm1.AddToStream(Source, Dest: TStream);
48  var
49    Size: Integer;
50  begin
51    Source.position := 0;
52    // Keep the size by puting it in the first byte
53    Size := Source.Size;
54    Dest.write(Size, SizeOf(Integer));
55    Dest.CopyFrom(Source, Source.size);
56  end;
57  
58  procedure TForm1.GetFromStream(Source, Dest: TStream; Index: Integer);
59  var
60    Size, I: Integer;
61  
62  begin
63    Source.Position := 0;
64    for i := 0 to index - 1 do
65    begin
66      Source.read(Size, SizeOf(Integer));
67      Source.Position := Source.Position + Size;
68    end;
69    // if where all the way up the file pointer then someting went wrong :(
70    if Source.position = Source.Size then
71      raise EAccessViolation.Create('Index Out Of Bounds');
72    // Get the desired file size
73    Source.read(Size, SizeOf(Integer));
74    // Clear Dest Buffer
75    Dest.Position := 0;
76    Dest.Size := 0;
77    Dest.CopyFrom(Source, Size);
78  end;