328 lines
13 KiB
Ada
328 lines
13 KiB
Ada
------------------------------------------------------------------------------
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-- ZLib for Ada thick binding. --
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-- --
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-- Copyright (C) 2002-2004 Dmitriy Anisimkov --
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-- --
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-- This library is free software; you can redistribute it and/or modify --
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-- it under the terms of the GNU General Public License as published by --
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-- the Free Software Foundation; either version 2 of the License, or (at --
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-- your option) any later version. --
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-- --
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-- This library is distributed in the hope that it will be useful, but --
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-- WITHOUT ANY WARRANTY; without even the implied warranty of --
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
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-- General Public License for more details. --
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-- --
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-- You should have received a copy of the GNU General Public License --
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-- along with this library; if not, write to the Free Software Foundation, --
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-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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------------------------------------------------------------------------------
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-- Id: zlib.ads,v 1.26 2004/09/06 06:53:19 vagul Exp
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with Ada.Streams;
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with Interfaces;
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package ZLib is
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ZLib_Error : exception;
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Status_Error : exception;
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type Compression_Level is new Integer range -1 .. 9;
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type Flush_Mode is private;
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type Compression_Method is private;
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type Window_Bits_Type is new Integer range 8 .. 15;
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type Memory_Level_Type is new Integer range 1 .. 9;
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type Unsigned_32 is new Interfaces.Unsigned_32;
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type Strategy_Type is private;
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type Header_Type is (None, Auto, Default, GZip);
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-- Header type usage have a some limitation for inflate.
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-- See comment for Inflate_Init.
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subtype Count is Ada.Streams.Stream_Element_Count;
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Default_Memory_Level : constant Memory_Level_Type := 8;
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Default_Window_Bits : constant Window_Bits_Type := 15;
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----------------------------------
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-- Compression method constants --
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----------------------------------
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Deflated : constant Compression_Method;
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-- Only one method allowed in this ZLib version
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---------------------------------
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-- Compression level constants --
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---------------------------------
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No_Compression : constant Compression_Level := 0;
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Best_Speed : constant Compression_Level := 1;
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Best_Compression : constant Compression_Level := 9;
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Default_Compression : constant Compression_Level := -1;
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--------------------------
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-- Flush mode constants --
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--------------------------
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No_Flush : constant Flush_Mode;
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-- Regular way for compression, no flush
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Partial_Flush : constant Flush_Mode;
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-- Will be removed, use Z_SYNC_FLUSH instead
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Sync_Flush : constant Flush_Mode;
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-- All pending output is flushed to the output buffer and the output
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-- is aligned on a byte boundary, so that the decompressor can get all
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-- input data available so far. (In particular avail_in is zero after the
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-- call if enough output space has been provided before the call.)
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-- Flushing may degrade compression for some compression algorithms and so
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-- it should be used only when necessary.
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Block_Flush : constant Flush_Mode;
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-- Z_BLOCK requests that inflate() stop
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-- if and when it get to the next deflate block boundary. When decoding the
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-- zlib or gzip format, this will cause inflate() to return immediately
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-- after the header and before the first block. When doing a raw inflate,
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-- inflate() will go ahead and process the first block, and will return
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-- when it gets to the end of that block, or when it runs out of data.
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Full_Flush : constant Flush_Mode;
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-- All output is flushed as with SYNC_FLUSH, and the compression state
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-- is reset so that decompression can restart from this point if previous
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-- compressed data has been damaged or if random access is desired. Using
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-- Full_Flush too often can seriously degrade the compression.
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Finish : constant Flush_Mode;
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-- Just for tell the compressor that input data is complete.
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------------------------------------
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-- Compression strategy constants --
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------------------------------------
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-- RLE stategy could be used only in version 1.2.0 and later.
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Filtered : constant Strategy_Type;
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Huffman_Only : constant Strategy_Type;
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RLE : constant Strategy_Type;
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Default_Strategy : constant Strategy_Type;
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Default_Buffer_Size : constant := 4096;
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type Filter_Type is tagged limited private;
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-- The filter is for compression and for decompression.
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-- The usage of the type is depend of its initialization.
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function Version return String;
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pragma Inline (Version);
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-- Return string representation of the ZLib version.
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procedure Deflate_Init
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(Filter : in out Filter_Type;
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Level : in Compression_Level := Default_Compression;
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Strategy : in Strategy_Type := Default_Strategy;
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Method : in Compression_Method := Deflated;
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Window_Bits : in Window_Bits_Type := Default_Window_Bits;
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Memory_Level : in Memory_Level_Type := Default_Memory_Level;
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Header : in Header_Type := Default);
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-- Compressor initialization.
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-- When Header parameter is Auto or Default, then default zlib header
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-- would be provided for compressed data.
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-- When Header is GZip, then gzip header would be set instead of
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-- default header.
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-- When Header is None, no header would be set for compressed data.
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procedure Inflate_Init
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(Filter : in out Filter_Type;
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Window_Bits : in Window_Bits_Type := Default_Window_Bits;
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Header : in Header_Type := Default);
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-- Decompressor initialization.
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-- Default header type mean that ZLib default header is expecting in the
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-- input compressed stream.
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-- Header type None mean that no header is expecting in the input stream.
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-- GZip header type mean that GZip header is expecting in the
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-- input compressed stream.
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-- Auto header type mean that header type (GZip or Native) would be
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-- detected automatically in the input stream.
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-- Note that header types parameter values None, GZip and Auto are
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-- supported for inflate routine only in ZLib versions 1.2.0.2 and later.
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-- Deflate_Init is supporting all header types.
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function Is_Open (Filter : in Filter_Type) return Boolean;
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pragma Inline (Is_Open);
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-- Is the filter opened for compression or decompression.
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procedure Close
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(Filter : in out Filter_Type;
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Ignore_Error : in Boolean := False);
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-- Closing the compression or decompressor.
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-- If stream is closing before the complete and Ignore_Error is False,
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-- The exception would be raised.
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generic
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with procedure Data_In
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(Item : out Ada.Streams.Stream_Element_Array;
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Last : out Ada.Streams.Stream_Element_Offset);
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with procedure Data_Out
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(Item : in Ada.Streams.Stream_Element_Array);
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procedure Generic_Translate
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(Filter : in out Filter_Type;
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In_Buffer_Size : in Integer := Default_Buffer_Size;
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Out_Buffer_Size : in Integer := Default_Buffer_Size);
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-- Compress/decompress data fetch from Data_In routine and pass the result
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-- to the Data_Out routine. User should provide Data_In and Data_Out
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-- for compression/decompression data flow.
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-- Compression or decompression depend on Filter initialization.
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function Total_In (Filter : in Filter_Type) return Count;
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pragma Inline (Total_In);
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-- Returns total number of input bytes read so far
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function Total_Out (Filter : in Filter_Type) return Count;
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pragma Inline (Total_Out);
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-- Returns total number of bytes output so far
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function CRC32
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(CRC : in Unsigned_32;
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Data : in Ada.Streams.Stream_Element_Array)
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return Unsigned_32;
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pragma Inline (CRC32);
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-- Compute CRC32, it could be necessary for make gzip format
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procedure CRC32
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(CRC : in out Unsigned_32;
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Data : in Ada.Streams.Stream_Element_Array);
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pragma Inline (CRC32);
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-- Compute CRC32, it could be necessary for make gzip format
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-------------------------------------------------
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-- Below is more complex low level routines. --
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-------------------------------------------------
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procedure Translate
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(Filter : in out Filter_Type;
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In_Data : in Ada.Streams.Stream_Element_Array;
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In_Last : out Ada.Streams.Stream_Element_Offset;
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Out_Data : out Ada.Streams.Stream_Element_Array;
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Out_Last : out Ada.Streams.Stream_Element_Offset;
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Flush : in Flush_Mode);
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-- Compress/decompress the In_Data buffer and place the result into
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-- Out_Data. In_Last is the index of last element from In_Data accepted by
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-- the Filter. Out_Last is the last element of the received data from
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-- Filter. To tell the filter that incoming data are complete put the
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-- Flush parameter to Finish.
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function Stream_End (Filter : in Filter_Type) return Boolean;
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pragma Inline (Stream_End);
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-- Return the true when the stream is complete.
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procedure Flush
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(Filter : in out Filter_Type;
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Out_Data : out Ada.Streams.Stream_Element_Array;
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Out_Last : out Ada.Streams.Stream_Element_Offset;
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Flush : in Flush_Mode);
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pragma Inline (Flush);
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-- Flushing the data from the compressor.
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generic
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with procedure Write
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(Item : in Ada.Streams.Stream_Element_Array);
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-- User should provide this routine for accept
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-- compressed/decompressed data.
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Buffer_Size : in Ada.Streams.Stream_Element_Offset
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:= Default_Buffer_Size;
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-- Buffer size for Write user routine.
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procedure Write
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(Filter : in out Filter_Type;
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Item : in Ada.Streams.Stream_Element_Array;
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Flush : in Flush_Mode := No_Flush);
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-- Compress/Decompress data from Item to the generic parameter procedure
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-- Write. Output buffer size could be set in Buffer_Size generic parameter.
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generic
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with procedure Read
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(Item : out Ada.Streams.Stream_Element_Array;
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Last : out Ada.Streams.Stream_Element_Offset);
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-- User should provide data for compression/decompression
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-- thru this routine.
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Buffer : in out Ada.Streams.Stream_Element_Array;
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-- Buffer for keep remaining data from the previous
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-- back read.
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Rest_First, Rest_Last : in out Ada.Streams.Stream_Element_Offset;
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-- Rest_First have to be initialized to Buffer'Last + 1
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-- Rest_Last have to be initialized to Buffer'Last
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-- before usage.
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Allow_Read_Some : in Boolean := False;
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-- Is it allowed to return Last < Item'Last before end of data.
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procedure Read
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(Filter : in out Filter_Type;
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Item : out Ada.Streams.Stream_Element_Array;
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Last : out Ada.Streams.Stream_Element_Offset;
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Flush : in Flush_Mode := No_Flush);
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-- Compress/Decompress data from generic parameter procedure Read to the
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-- Item. User should provide Buffer and initialized Rest_First, Rest_Last
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-- indicators. If Allow_Read_Some is True, Read routines could return
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-- Last < Item'Last only at end of stream.
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private
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use Ada.Streams;
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pragma Assert (Ada.Streams.Stream_Element'Size = 8);
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pragma Assert (Ada.Streams.Stream_Element'Modulus = 2**8);
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type Flush_Mode is new Integer range 0 .. 5;
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type Compression_Method is new Integer range 8 .. 8;
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type Strategy_Type is new Integer range 0 .. 3;
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No_Flush : constant Flush_Mode := 0;
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Partial_Flush : constant Flush_Mode := 1;
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Sync_Flush : constant Flush_Mode := 2;
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Full_Flush : constant Flush_Mode := 3;
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Finish : constant Flush_Mode := 4;
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Block_Flush : constant Flush_Mode := 5;
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Filtered : constant Strategy_Type := 1;
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Huffman_Only : constant Strategy_Type := 2;
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RLE : constant Strategy_Type := 3;
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Default_Strategy : constant Strategy_Type := 0;
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Deflated : constant Compression_Method := 8;
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type Z_Stream;
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type Z_Stream_Access is access all Z_Stream;
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type Filter_Type is tagged limited record
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Strm : Z_Stream_Access;
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Compression : Boolean;
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Stream_End : Boolean;
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Header : Header_Type;
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CRC : Unsigned_32;
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Offset : Stream_Element_Offset;
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-- Offset for gzip header/footer output.
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end record;
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end ZLib;
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