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--  LZMA.Encoding - a standalone, generic LZMA encoder.
--  See body for credits and other informations.

--  Examples of use:
--    LZMA_Enc, a standalone encoder to .lzma files
--    Zip.Compress.LZMA_E, creates Zip files entries with LZMA encoding

with Interfaces;

package LZMA.Encoding is

  subtype Byte is Interfaces.Unsigned_8;

  --  Low level: faster but weaker compression
  --  High level: slower but stronger compression
  --
  type Compression_level is (
    Level_0,  --  no LZ compression
    Level_1,  --  uses Info-Zip's match finder for Deflate (32KB  sliding window), level 6
    Level_2,  --  uses Info-Zip's match finder for Deflate (32KB  sliding window), level 10
    Level_3   --  uses LZMA SDK's BT4 match finder, dictionary's size specified in dictionary_size
  );

  generic
    --  Input of data:
    with function  Read_byte return Byte;
    with function  More_bytes return Boolean;
    --  Output of LZMA-compressed data:
    with procedure Write_byte (b: Byte);
    --
  procedure Encode(
    level                  : Compression_level           := Level_1;
    literal_context_bits   : Literal_context_bits_range  := 3;   --  Bits of last byte are used.
    literal_position_bits  : Literal_position_bits_range := 0;   --  Position mod 2**bits is used.
    position_bits          : Position_bits_range         := 2;   --  Position mod 2**bits is used.
    end_marker             : Boolean := True;   --  Produce an End-Of-Stream marker (*) ?
    uncompressed_size_info : Boolean := False;  --  Optional extra header needed for .lzma files.
    dictionary_size        : Natural := Default_dictionary_size  --  Not used by Level_1, Level_2.
  );

  --  (*) In PKWARE's Appnote (5.8.9), the use of an EOS marker is "highly recommended" for LZMA.

end LZMA.Encoding;