Concatenate and compress files into one destination file in delphi

// Concatenate and compress files into one destination file

uses
  Zlib;

procedure CompressFiles(Files : TStrings; const Filename : String);
var
  infile, outfile, tmpFile : TFileStream;
  compr : TCompressionStream;
  i,l : Integer;
  s : String;

begin
  if Files.Count > 0 then
  begin
    outFile := TFileStream.Create(Filename,fmCreate);
    try
      { the number of files }
      l := Files.Count;
      outfile.Write(l,SizeOf(l));
      for i := 0 to Files.Count-1 do
      begin
        infile := TFileStream.Create(Files[i],fmOpenRead);
        try
          { the original filename }
          s := ExtractFilename(Files[i]);
          l := Length(s);
          outfile.Write(l,SizeOf(l));
          outfile.Write(s[1],l);
          { the original filesize }
          l := infile.Size;
          outfile.Write(l,SizeOf(l));
          { compress and store the file temporary}
          tmpFile := TFileStream.Create('tmp',fmCreate);
          compr := TCompressionStream.Create(clMax,tmpfile);
          try
            compr.CopyFrom(infile,l);
          finally
            compr.Free;
            tmpFile.Free;
          end;
          { append the compressed file to the destination file }
          tmpFile := TFileStream.Create('tmp',fmOpenRead);
          try
            outfile.CopyFrom(tmpFile,0);
          finally
            tmpFile.Free;
          end;
        finally
          infile.Free;
        end;
      end;
    finally
      outfile.Free;
    end;
    DeleteFile('tmp');
  end;
end;

procedure DecompressFiles(const Filename, DestDirectory : String);
var
  dest,s : String;
  decompr : TDecompressionStream;
  infile, outfile : TFilestream;
  i,l,c : Integer;
begin
  // IncludeTrailingPathDelimiter (D6/D7 only)
  dest := IncludeTrailingPathDelimiter(DestDirectory);

  infile := TFileStream.Create(Filename,fmOpenRead);
  try
    { number of files }
    infile.Read(c,SizeOf(c));
    for i := 1 to c do
    begin
      { read filename }
      infile.Read(l,SizeOf(l));
      SetLength(s,l);
      infile.Read(s[1],l);
      { read filesize }
      infile.Read(l,SizeOf(l));
      { decompress the files and store it }
      s := dest+s; //include the path
      outfile := TFileStream.Create(s,fmCreate);
      decompr := TDecompressionStream.Create(infile);
      try
        outfile.CopyFrom(decompr,l);
      finally
        outfile.Free;
        decompr.Free;
      end;
    end;
  finally
    infile.Free;
  end;
end;