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 1.8 2004/05/31 10:53:40 vagul Exp $
 10
 11--  Test/demo program for the generic read interface.
 12
 13with Ada.Numerics.Discrete_Random;
 14with Ada.Streams;
 15with Ada.Text_IO;
 16
 17with ZLib;
 18
 19procedure 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
 72                           (Read,
 73                            Read_Buffer,
 74                            Rest_First => Read_First,
 75                            Rest_Last  => Read_Last);
 76
 77   ----------
 78   -- Read --
 79   ----------
 80
 81   procedure Read
 82     (Item : out Stream_Element_Array;
 83      Last : out Stream_Element_Offset) is
 84   begin
 85      Last := Stream_Element_Offset'Min
 86               (Item'Last,
 87                Item'First + File_Size - Offset);
 88
 89      for J in Item'First .. Last loop
 90         if J < Item'First + Period then
 91            Item (J) := Random_Elements.Random (Gen);
 92         else
 93            Item (J) := Item (J - Period);
 94         end if;
 95
 96         Offset   := Offset + 1;
 97      end loop;
 98   end Read;
 99
100   -----------
101   -- Reset --
102   -----------
103
104   procedure Reset is
105   begin
106      Random_Elements.Reset (Gen, Init_Random);
107      Pack_Size := 0;
108      Offset := 1;
109      Read_First := Read_Buffer'Last + 1;
110      Read_Last  := Read_Buffer'Last;
111   end Reset;
112
113begin
114   Ada.Text_IO.Put_Line ("ZLib " & ZLib.Version);
115
116   loop
117      for Level in ZLib.Compression_Level'Range loop
118
119         Ada.Text_IO.Put ("Level ="
120            & ZLib.Compression_Level'Image (Level));
121
122         --  Deflate using generic instantiation.
123
124         ZLib.Deflate_Init
125               (Filter,
126                Level,
127                Header => Header);
128
129         Reset;
130
131         Ada.Text_IO.Put
132           (Stream_Element_Offset'Image (File_Size) & " ->");
133
134         loop
135            declare
136               Buffer : Stream_Element_Array (1 .. 1024);
137               Last   : Stream_Element_Offset;
138            begin
139               Read (Filter, Buffer, Last);
140
141               Pack_Size := Pack_Size + Last - Buffer'First + 1;
142
143               exit when Last < Buffer'Last;
144            end;
145         end loop;
146
147         Ada.Text_IO.Put_Line (Stream_Element_Offset'Image (Pack_Size));
148
149         ZLib.Close (Filter);
150      end loop;
151
152      exit when not Continuous;
153
154      File_Size := File_Size + 1;
155   end loop;
156end Read;