------------------------------------------------------------------------------
-- ZLib for Ada thick binding. --
-- --
-- Copyright (C) 2002-2004 Dmitriy Anisimkov --
-- --
-- This library is free software; you can redistribute it and/or modify --
-- it under the terms of the GNU General Public License as published by --
-- the Free Software Foundation; either version 2 of the License, or (at --
-- your option) any later version. --
-- --
-- This library is distributed in the hope that it will be useful, but --
-- WITHOUT ANY WARRANTY; without even the implied warranty of --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. --
-- --
-- You should have received a copy of the GNU General Public License --
-- along with this library; if not, write to the Free Software Foundation, --
-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
------------------------------------------------------------------------------
-- $Id: zlib.ads,v 1.1.1.2 2023/03/21 16:41:53 christos Exp $
with Ada.Streams;
with Interfaces;
package ZLib is
ZLib_Error : exception;
Status_Error : exception;
type Compression_Level is new Integer range -1 .. 9;
type Flush_Mode is private;
type Compression_Method is private;
type Window_Bits_Type is new Integer range 8 .. 15;
type Memory_Level_Type is new Integer range 1 .. 9;
type Unsigned_32 is new Interfaces.Unsigned_32;
type Strategy_Type is private;
type Header_Type is (None, Auto, Default, GZip);
-- Header type usage have a some limitation for inflate.
-- See comment for Inflate_Init.
subtype Count is Ada.Streams.Stream_Element_Count;
Default_Memory_Level : constant Memory_Level_Type := 8;
Default_Window_Bits : constant Window_Bits_Type := 15;
----------------------------------
-- Compression method constants --
----------------------------------
Deflated : constant Compression_Method;
-- Only one method allowed in this ZLib version
---------------------------------
-- Compression level constants --
---------------------------------
No_Compression : constant Compression_Level := 0;
Best_Speed : constant Compression_Level := 1;
Best_Compression : constant Compression_Level := 9;
Default_Compression : constant Compression_Level := -1;
--------------------------
-- Flush mode constants --
--------------------------
No_Flush : constant Flush_Mode;
-- Regular way for compression, no flush
Partial_Flush : constant Flush_Mode;
-- Will be removed, use Z_SYNC_FLUSH instead
Sync_Flush : constant Flush_Mode;
-- All pending output is flushed to the output buffer and the output
-- is aligned on a byte boundary, so that the decompressor can get all
-- input data available so far. (In particular avail_in is zero after the
-- call if enough output space has been provided before the call.)
-- Flushing may degrade compression for some compression algorithms and so
-- it should be used only when necessary.
Block_Flush : constant Flush_Mode;
-- Z_BLOCK requests that inflate() stop
-- if and when it get to the next deflate block boundary. When decoding the
-- zlib or gzip format, this will cause inflate() to return immediately
-- after the header and before the first block. When doing a raw inflate,
-- inflate() will go ahead and process the first block, and will return
-- when it gets to the end of that block, or when it runs out of data.
Full_Flush : constant Flush_Mode;
-- All output is flushed as with SYNC_FLUSH, and the compression state
-- is reset so that decompression can restart from this point if previous
-- compressed data has been damaged or if random access is desired. Using
-- Full_Flush too often can seriously degrade the compression.
Finish : constant Flush_Mode;
-- Just for tell the compressor that input data is complete.
------------------------------------
-- Compression strategy constants --
------------------------------------
-- RLE stategy could be used only in version 1.2.0 and later.
Filtered : constant Strategy_Type;
Huffman_Only : constant Strategy_Type;
RLE : constant Strategy_Type;
Default_Strategy : constant Strategy_Type;
Default_Buffer_Size : constant := 4096;
type Filter_Type is tagged limited private;
-- The filter is for compression and for decompression.
-- The usage of the type is depend of its initialization.
function Version return String;
pragma Inline (Version);
-- Return string representation of the ZLib version.
procedure Deflate_Init
(Filter : in out Filter_Type;
Level : in Compression_Level := Default_Compression;
Strategy : in Strategy_Type := Default_Strategy;
Method : in Compression_Method := Deflated;
Window_Bits : in Window_Bits_Type := Default_Window_Bits;
Memory_Level : in Memory_Level_Type := Default_Memory_Level;
Header : in Header_Type := Default);
-- Compressor initialization.
-- When Header parameter is Auto or Default, then default zlib header
-- would be provided for compressed data.
-- When Header is GZip, then gzip header would be set instead of
-- default header.
-- When Header is None, no header would be set for compressed data.
procedure Inflate_Init
(Filter : in out Filter_Type;
Window_Bits : in Window_Bits_Type := Default_Window_Bits;
Header : in Header_Type := Default);
-- Decompressor initialization.
-- Default header type mean that ZLib default header is expecting in the
-- input compressed stream.
-- Header type None mean that no header is expecting in the input stream.
-- GZip header type mean that GZip header is expecting in the
-- input compressed stream.
-- Auto header type mean that header type (GZip or Native) would be
-- detected automatically in the input stream.
-- Note that header types parameter values None, GZip and Auto are
-- supported for inflate routine only in ZLib versions 1.2.0.2 and later.
-- Deflate_Init is supporting all header types.
function Is_Open (Filter : in Filter_Type) return Boolean;
pragma Inline (Is_Open);
-- Is the filter opened for compression or decompression.
procedure Close
(Filter : in out Filter_Type;
Ignore_Error : in Boolean := False);
-- Closing the compression or decompressor.
-- If stream is closing before the complete and Ignore_Error is False,
-- The exception would be raised.
generic
with procedure Data_In
(Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
with procedure Data_Out
(Item : in Ada.Streams.Stream_Element_Array);
procedure Generic_Translate
(Filter : in out Filter_Type;
In_Buffer_Size : in Integer := Default_Buffer_Size;
Out_Buffer_Size : in Integer := Default_Buffer_Size);
-- Compress/decompress data fetch from Data_In routine and pass the result
-- to the Data_Out routine. User should provide Data_In and Data_Out
-- for compression/decompression data flow.
-- Compression or decompression depend on Filter initialization.
function Total_In (Filter : in Filter_Type) return Count;
pragma Inline (Total_In);
-- Returns total number of input bytes read so far
function Total_Out (Filter : in Filter_Type) return Count;
pragma Inline (Total_Out);
-- Returns total number of bytes output so far
function CRC32
(CRC : in Unsigned_32;
Data : in Ada.Streams.Stream_Element_Array)
return Unsigned_32;
pragma Inline (CRC32);
-- Compute CRC32, it could be necessary for make gzip format
procedure CRC32
(CRC : in out Unsigned_32;
Data : in Ada.Streams.Stream_Element_Array);
pragma Inline (CRC32);
-- Compute CRC32, it could be necessary for make gzip format
-------------------------------------------------
-- Below is more complex low level routines. --
-------------------------------------------------
procedure Translate
(Filter : in out Filter_Type;
In_Data : in Ada.Streams.Stream_Element_Array;
In_Last : out Ada.Streams.Stream_Element_Offset;
Out_Data : out Ada.Streams.Stream_Element_Array;
Out_Last : out Ada.Streams.Stream_Element_Offset;
Flush : in Flush_Mode);
-- Compress/decompress the In_Data buffer and place the result into
-- Out_Data. In_Last is the index of last element from In_Data accepted by
-- the Filter. Out_Last is the last element of the received data from
-- Filter. To tell the filter that incoming data are complete put the
-- Flush parameter to Finish.
function Stream_End (Filter : in Filter_Type) return Boolean;
pragma Inline (Stream_End);
-- Return the true when the stream is complete.
procedure Flush
(Filter : in out Filter_Type;
Out_Data : out Ada.Streams.Stream_Element_Array;
Out_Last : out Ada.Streams.Stream_Element_Offset;
Flush : in Flush_Mode);
pragma Inline (Flush);
-- Flushing the data from the compressor.
generic
with procedure Write
(Item : in Ada.Streams.Stream_Element_Array);
-- User should provide this routine for accept
-- compressed/decompressed data.
Buffer_Size : in Ada.Streams.Stream_Element_Offset
:= Default_Buffer_Size;
-- Buffer size for Write user routine.
procedure Write
(Filter : in out Filter_Type;
Item : in Ada.Streams.Stream_Element_Array;
Flush : in Flush_Mode := No_Flush);
-- Compress/Decompress data from Item to the generic parameter procedure
-- Write. Output buffer size could be set in Buffer_Size generic parameter.
generic
with procedure Read
(Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
-- User should provide data for compression/decompression
-- thru this routine.
Buffer : in out Ada.Streams.Stream_Element_Array;
-- Buffer for keep remaining data from the previous
-- back read.
Rest_First, Rest_Last : in out Ada.Streams.Stream_Element_Offset;
-- Rest_First have to be initialized to Buffer'Last + 1
-- Rest_Last have to be initialized to Buffer'Last
-- before usage.
Allow_Read_Some : in Boolean := False;
-- Is it allowed to return Last < Item'Last before end of data.
procedure Read
(Filter : in out Filter_Type;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset;
Flush : in Flush_Mode := No_Flush);
-- Compress/Decompress data from generic parameter procedure Read to the
-- Item. User should provide Buffer and initialized Rest_First, Rest_Last
-- indicators. If Allow_Read_Some is True, Read routines could return
-- Last < Item'Last only at end of stream.
private
use Ada.Streams;
pragma Assert (Ada.Streams.Stream_Element'Size = 8);
pragma Assert (Ada.Streams.Stream_Element'Modulus = 2**8);
type Flush_Mode is new Integer range 0 .. 5;
type Compression_Method is new Integer range 8 .. 8;
type Strategy_Type is new Integer range 0 .. 3;
No_Flush : constant Flush_Mode := 0;
Partial_Flush : constant Flush_Mode := 1;
Sync_Flush : constant Flush_Mode := 2;
Full_Flush : constant Flush_Mode := 3;
Finish : constant Flush_Mode := 4;
Block_Flush : constant Flush_Mode := 5;
Filtered : constant Strategy_Type := 1;
Huffman_Only : constant Strategy_Type := 2;
RLE : constant Strategy_Type := 3;
Default_Strategy : constant Strategy_Type := 0;
Deflated : constant Compression_Method := 8;
type Z_Stream;
type Z_Stream_Access is access all Z_Stream;
type Filter_Type is tagged limited record
Strm : Z_Stream_Access;
Compression : Boolean;
Stream_End : Boolean;
Header : Header_Type;
CRC : Unsigned_32;
Offset : Stream_Element_Offset;
-- Offset for gzip header/footer output.
end record;
end ZLib;