read.adb
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----------------------------------------------------------------
-- ZLib for Ada thick binding. --
-- --
-- Copyright (C) 2002-2003 Dmitriy Anisimkov --
-- --
-- Open source license information is in the zlib.ads file. --
----------------------------------------------------------------
-- $Id: read.adb,v 1.8 2004/05/31 10:53:40 vagul Exp $
-- Test/demo program for the generic read interface.
with Ada.Numerics.Discrete_Random;
with Ada.Streams;
with Ada.Text_IO;
with ZLib;
procedure Read is
use Ada.Streams;
------------------------------------
-- Test configuration parameters --
------------------------------------
File_Size : Stream_Element_Offset := 100_000;
Continuous : constant Boolean := False;
-- If this constant is True, the test would be repeated again and again,
-- with increment File_Size for every iteration.
Header : constant ZLib.Header_Type := ZLib.Default;
-- Do not use Header other than Default in ZLib versions 1.1.4 and older.
Init_Random : constant := 8;
-- We are using the same random sequence, in case of we catch bug,
-- so we would be able to reproduce it.
-- End --
Pack_Size : Stream_Element_Offset;
Offset : Stream_Element_Offset;
Filter : ZLib.Filter_Type;
subtype Visible_Symbols
is Stream_Element range 16#20# .. 16#7E#;
package Random_Elements is new
Ada.Numerics.Discrete_Random (Visible_Symbols);
Gen : Random_Elements.Generator;
Period : constant Stream_Element_Offset := 200;
-- Period constant variable for random generator not to be very random.
-- Bigger period, harder random.
Read_Buffer : Stream_Element_Array (1 .. 2048);
Read_First : Stream_Element_Offset;
Read_Last : Stream_Element_Offset;
procedure Reset;
procedure Read
(Item : out Stream_Element_Array;
Last : out Stream_Element_Offset);
-- this procedure is for generic instantiation of
-- ZLib.Read
-- reading data from the File_In.
procedure Read is new ZLib.Read
(Read,
Read_Buffer,
Rest_First => Read_First,
Rest_Last => Read_Last);
----------
-- Read --
----------
procedure Read
(Item : out Stream_Element_Array;
Last : out Stream_Element_Offset) is
begin
Last := Stream_Element_Offset'Min
(Item'Last,
Item'First + File_Size - Offset);
for J in Item'First .. Last loop
if J < Item'First + Period then
Item (J) := Random_Elements.Random (Gen);
else
Item (J) := Item (J - Period);
end if;
Offset := Offset + 1;
end loop;
end Read;
-----------
-- Reset --
-----------
procedure Reset is
begin
Random_Elements.Reset (Gen, Init_Random);
Pack_Size := 0;
Offset := 1;
Read_First := Read_Buffer'Last + 1;
Read_Last := Read_Buffer'Last;
end Reset;
begin
Ada.Text_IO.Put_Line ("ZLib " & ZLib.Version);
loop
for Level in ZLib.Compression_Level'Range loop
Ada.Text_IO.Put ("Level ="
& ZLib.Compression_Level'Image (Level));
-- Deflate using generic instantiation.
ZLib.Deflate_Init
(Filter,
Level,
Header => Header);
Reset;
Ada.Text_IO.Put
(Stream_Element_Offset'Image (File_Size) & " ->");
loop
declare
Buffer : Stream_Element_Array (1 .. 1024);
Last : Stream_Element_Offset;
begin
Read (Filter, Buffer, Last);
Pack_Size := Pack_Size + Last - Buffer'First + 1;
exit when Last < Buffer'Last;
end;
end loop;
Ada.Text_IO.Put_Line (Stream_Element_Offset'Image (Pack_Size));
ZLib.Close (Filter);
end loop;
exit when not Continuous;
File_Size := File_Size + 1;
end loop;
end Read;