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--  Standalone LZ77 compression (encoding) package.
---------------------------------------------------
--  This is a collection of various free LZ77 match finders and encoders.
--  The differences reside in the way matches are found, or skipped.
--  See body (lz77.adb) for details and credits.
--
--  Pure Ada 95+ code, 100% portable: OS-, CPU- and compiler- independent.

--  Legal licensing note:

--  Copyright (c) 2016 Gautier de Montmollin (maintainer of the Ada version)

--  Permission is hereby granted, free of charge, to any person obtaining a copy
--  of this software and associated documentation files (the "Software"), to deal
--  in the Software without restriction, including without limitation the rights
--  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
--  copies of the Software, and to permit persons to whom the Software is
--  furnished to do so, subject to the following conditions:

--  The above copyright notice and this permission notice shall be included in
--  all copies or substantial portions of the Software.

--  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
--  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
--  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
--  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
--  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
--  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
--  THE SOFTWARE.

-- NB: this is the MIT License, as found 21-Aug-2016 on the site
-- http://www.opensource.org/licenses/mit-license.php

with Interfaces;

package LZ77 is

  type Method_Type is (
    --  Use the LZHuf algorithm (see body for details and credits)
    LZHuf,
    --  Use the Info-Zip algorithm, levels 4-10 (see body for details and credits)
    IZ_4,
    IZ_5,
    IZ_6,
    IZ_7,
    IZ_8,
    IZ_9,
    IZ_10,
    --  Use LZMA SDK's BT4 algorithm (see body for details and credits)
    BT4
  );

  subtype Byte is Interfaces.Unsigned_8;

  generic
    ----- LZSS Parameters -----
    String_buffer_size : Integer := 2**12;
    Look_Ahead         : Integer := 65;
    Threshold          : Integer := 2;
    --
    Method: Method_Type;
    --
    -- Input of data:
    with function  Read_byte return Byte;
    with function  More_bytes return Boolean;
    -- Output of LZ-compressed data:
    with procedure Write_literal( b: Byte );
    with procedure Write_DL_code( distance, length: Integer );
    --
    LZMA_friendly: Boolean:= True;  --  Up to 4 recent distances may be preferred
  procedure Encode;

end LZ77;