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   1  --  Standalone BZip2 decoder (for .bz2 files)
   2  
   3  with BZip2.Decoding;
   4  
   5  with Ada.Text_IO,
   6       Ada.Streams.Stream_IO,
   7       Ada.Command_Line;
   8  
   9  procedure BZip2_Dec is
  10  
  11    use Ada.Streams.Stream_IO, BZip2;
  12  
  13    f_in, f_out : Ada.Streams.Stream_IO.File_Type;
  14  
  15    --  NB: The Byte I/O below is not buffered, so it is very slow.
  16    --  You need to implement a circular buffer of type Stream_Element_Array for a fast I/O.
  17    --  For instance, see the BlockRead in the Zip package for how to do it.
  18  
  19    function Demo_Read_Byte return Byte is
  20      b : Byte;
  21    begin
  22      Byte'Read (Stream (f_in), b);
  23      return b;
  24    end Demo_Read_Byte;
  25  
  26    procedure Demo_Write_Byte (b : Byte) is
  27    begin
  28      Byte'Write (Stream (f_out), b);
  29    end Demo_Write_Byte;
  30  
  31    package My_BZip2 is new BZip2.Decoding
  32      (Demo_Read_Byte, Demo_Write_Byte, check_CRC => True);
  33  
  34    use Ada.Command_Line, Ada.Text_IO;
  35  
  36    default : constant String := "bunzip.out";
  37  
  38  begin
  39    if Argument_Count = 0 then
  40      Put_Line ("BZip2_Dec: a standalone BZip2 decoder.");
  41      New_Line;
  42      Put_Line ("Usage: bzip2_dec infile.bz2 {outfile}");
  43      New_Line;
  44      Put_Line ("Decompresses a bzip2 compressed file (.bz2)");
  45      Put_Line ("Output: if outfile is not given, the name """ & default & """ will be used");
  46      New_Line;
  47      Put ("Press Return");
  48      Skip_Line;
  49    else
  50      Open (f_in, In_File, Argument (1));
  51      Create (f_out, Out_File, (if Argument_Count > 1 then Argument (2) else default));
  52      My_BZip2.Decompress;
  53      Close (f_out);
  54    end if;
  55  end BZip2_Dec;