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