zlib/contrib/ada/read.adb

   1 ----------------------------------------------------------------
   2 --  ZLib for Ada thick binding.                               --
   3 --                                                            --
   4 --  Copyright (C) 2002-2003 Dmitriy Anisimkov                 --
   5 --                                                            --
   6 --  Open source license information is in the zlib.ads file.  --
   7 ----------------------------------------------------------------
   8
   9 --  $Id: read.adb,v 1.1.1.1 2004/10/11 17:44:23 tromey Exp $
  10
  11 --  Test/demo program for the generic read interface.
  12
  13 with Ada.Numerics.Discrete_Random;
  14 with Ada.Streams;
  15 with Ada.Text_IO;
  16
  17 with ZLib;
  18
  19 procedure Read is
  20
  21    use Ada.Streams;
  22
  23    ------------------------------------
  24    --  Test configuration parameters --
  25    ------------------------------------
  26
  27    File_Size   : Stream_Element_Offset := 100_000;
  28
  29    Continuous  : constant Boolean          := False;
  30    --  If this constant is True, the test would be repeated again and again,
  31    --  with increment File_Size for every iteration.
  32
  33    Header      : constant ZLib.Header_Type := ZLib.Default;
  34    --  Do not use Header other than Default in ZLib versions 1.1.4 and older.
  35
  36    Init_Random : constant := 8;
  37    --  We are using the same random sequence, in case of we catch bug,
  38    --  so we would be able to reproduce it.
  39
  40    -- End --
  41
  42    Pack_Size : Stream_Element_Offset;
  43    Offset    : Stream_Element_Offset;
  44
  45    Filter     : ZLib.Filter_Type;
  46
  47    subtype Visible_Symbols
  48       is Stream_Element range 16#20# .. 16#7E#;
  49
  50    package Random_Elements is new
  51       Ada.Numerics.Discrete_Random (Visible_Symbols);
  52
  53    Gen : Random_Elements.Generator;
  54    Period  : constant Stream_Element_Offset := 200;
  55    --  Period constant variable for random generator not to be very random.
  56    --  Bigger period, harder random.
  57
  58    Read_Buffer : Stream_Element_Array (1 .. 2048);
  59    Read_First  : Stream_Element_Offset;
  60    Read_Last   : Stream_Element_Offset;
  61
  62    procedure Reset;
  63
  64    procedure Read
  65      (Item : out Stream_Element_Array;
  66       Last : out Stream_Element_Offset);
  67    --  this procedure is for generic instantiation of
  68    --  ZLib.Read
  69    --  reading data from the File_In.
  70
  71    procedure Read is new ZLib.Read (Read, Read_Buffer, Read_First, Read_Last);
  72
  73    ----------
  74    -- Read --
  75    ----------
  76
  77    procedure Read
  78      (Item : out Stream_Element_Array;
  79       Last : out Stream_Element_Offset) is
  80    begin
  81       Last := Stream_Element_Offset'Min
  82                (Item'Last,
  83                 Item'First + File_Size - Offset);
  84
  85       for J in Item'First .. Last loop
  86          if J < Item'First + Period then
  87             Item (J) := Random_Elements.Random (Gen);
  88          else
  89             Item (J) := Item (J - Period);
  90          end if;
  91
  92          Offset   := Offset + 1;
  93       end loop;
  94    end Read;
  95
  96    -----------
  97    -- Reset --
  98    -----------
  99
 100    procedure Reset is
 101    begin
 102       Random_Elements.Reset (Gen, Init_Random);
 103       Pack_Size := 0;
 104       Offset := 1;
 105       Read_First := Read_Buffer'Last + 1;
 106    end Reset;
 107
 108 begin
 109    Ada.Text_IO.Put_Line ("ZLib " & ZLib.Version);
 110
 111    loop
 112       for Level in ZLib.Compression_Level'Range loop
 113
 114          Ada.Text_IO.Put ("Level ="
 115             & ZLib.Compression_Level'Image (Level));
 116
 117          --  Deflate using generic instantiation.
 118
 119          ZLib.Deflate_Init
 120                (Filter,
 121                 Level,
 122                 Header => Header);
 123
 124          Reset;
 125
 126          Ada.Text_IO.Put
 127            (Stream_Element_Offset'Image (File_Size) & " ->");
 128
 129          loop
 130             declare
 131                Buffer : Stream_Element_Array (1 .. 1024);
 132                Last   : Stream_Element_Offset;
 133             begin
 134                Read (Filter, Buffer, Last);
 135
 136                Pack_Size := Pack_Size + Last - Buffer'First + 1;
 137
 138                exit when Last < Buffer'Last;
 139             end;
 140          end loop;
 141
 142          Ada.Text_IO.Put_Line (Stream_Element_Offset'Image (Pack_Size));
 143
 144          ZLib.Close (Filter);
 145       end loop;
 146
 147       exit when not Continuous;
 148
 149       File_Size := File_Size + 1;
 150    end loop;
 151 end Read;