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113 lines
4.5 KiB
Ada
113 lines
4.5 KiB
Ada
----------------------------------------------------------------
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-- ZLib for Ada thick binding. --
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-- --
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-- Copyright (C) 2002-2024, Dmitriy Anisimkov --
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-- --
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-- Open source license information is in the zlib.ads file. --
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----------------------------------------------------------------
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package ZLib.Streams is
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type Stream_Mode is (In_Stream, Out_Stream, Duplex);
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type Stream_Access is access all Root_Stream_Type'Class;
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type Stream_Type is new Root_Stream_Type with private;
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overriding procedure Read
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(Stream : in out Stream_Type;
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Item : out Stream_Element_Array;
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Last : out Stream_Element_Offset);
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overriding procedure Write
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(Stream : in out Stream_Type;
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Item : in Stream_Element_Array);
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procedure Flush
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(Stream : in out Stream_Type;
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Mode : in Flush_Mode := Sync_Flush);
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-- Flush the written data to the back stream,
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-- all data placed to the compressor is flushing to the Back stream.
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-- Should not be used untill necessary, becouse it is decreasing
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-- compression.
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function End_Of_Stream (Stream : in Stream_Type) return Boolean;
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-- Returns True when no more data to read
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function Read_Total_In (Stream : in Stream_Type) return Count with Inline;
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-- Return total number of bytes read from back stream so far
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function Read_Total_Out (Stream : in Stream_Type) return Count with Inline;
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-- Return total number of bytes read so far
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function Write_Total_In (Stream : in Stream_Type) return Count with Inline;
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-- Return total number of bytes written so far
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function Write_Total_Out (Stream : in Stream_Type) return Count with Inline;
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-- Return total number of bytes written to the back stream
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procedure Create
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(Stream : out Stream_Type;
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Mode : in Stream_Mode;
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Back : in Stream_Access;
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Back_Compressed : in Boolean;
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Level : in Compression_Level := Default_Compression;
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Strategy : in Strategy_Type := Default_Strategy;
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Header : in Header_Type := Default;
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Read_Buffer_Size : in Stream_Element_Offset := Default_Buffer_Size;
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Write_Buffer_Size : in Stream_Element_Offset := Default_Buffer_Size);
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-- Create the Comression/Decompression stream.
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-- If mode is In_Stream then Write operation is disabled.
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-- If mode is Out_Stream then Read operation is disabled.
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-- If Back_Compressed is true then
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-- Data written to the Stream is compressing to the Back stream
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-- and data read from the Stream is decompressed data from the Back stream.
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-- If Back_Compressed is false then
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-- Data written to the Stream is decompressing to the Back stream
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-- and data read from the Stream is compressed data from the Back stream.
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-- !!! When the Need_Header is False ZLib-Ada is using undocumented
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-- ZLib 1.1.4 functionality to do not create/wait for ZLib headers.
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function Is_Open (Stream : in Stream_Type) return Boolean;
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procedure Close (Stream : in out Stream_Type);
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private
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type Buffer_Access is access all Stream_Element_Array;
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type Stream_Type is new Root_Stream_Type with record
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Mode : Stream_Mode;
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Buffer : Buffer_Access;
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Rest_First : Stream_Element_Offset;
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Rest_Last : Stream_Element_Offset;
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-- Buffer for Read operation.
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-- We need to have this buffer in the record because not all read data
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-- from back stream could be processed during the read operation.
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Ahead_Last : Stream_Element_Offset;
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-- Sometimes the decompressed data is over but the gzip footer still was
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-- not read from back stream. We should try to read ahead in case we are
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-- suspect this to detect end of stream proper.
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Buffer_Size : Stream_Element_Offset;
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-- Buffer size for write operation.
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-- We do not need to have this buffer in the record because all data
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-- could be processed in the write operation.
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Back : Stream_Access;
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Reader : Filter_Type;
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Writer : Filter_Type;
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end record;
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function End_Of_Stream (Stream : in Stream_Type) return Boolean is
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(Stream_End (Stream.Reader)
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and then Stream.Rest_First > Stream.Rest_Last
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and then Stream.Rest_Last >= Stream.Ahead_Last);
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end ZLib.Streams;
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