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smg_comms_skeys_s...    1 ------------------------------------------------------------------------------
smg_comms_skeys_s...    2 ------------------------------------------------------------------------------
smg_comms_skeys_s...    3 -- This file is part of 'CRC32'                                             --
smg_comms_skeys_s...    4 --                                                                          --
smg_comms_skeys_s...    5 -- You do not have, nor can you ever acquire the right to use, copy or      --
smg_comms_skeys_s...    6 -- distribute this software ; Should you use this software for any purpose, --
smg_comms_skeys_s...    7 -- or copy and distribute it to anyone or in any manner, you are breaking   --
smg_comms_skeys_s...    8 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
smg_comms_skeys_s...    9 -- continue doing so for the indefinite future. In any case, please         --
smg_comms_skeys_s...   10 -- always : read and understand any software ; verify any PGP signatures    --
smg_comms_skeys_s...   11 -- that you use - for any purpose.                                          --
smg_comms_skeys_s...   12 --                                                                          --
smg_comms_skeys_s...   13 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
smg_comms_skeys_s...   14 ------------------------------------------------------------------------------
smg_comms_skeys_s...   15 ------------------------------------------------------------------------------
smg_comms_skeys_s...   16 
smg_comms_skeys_s...   17   -- CRC32 implementation
smg_comms_skeys_s...   18   -- S.MG, 2018
smg_comms_skeys_s...   19 
smg_comms_skeys_s...   20 package body CRC32 is
smg_comms_skeys_s...   21   function CRC( S: in String ) return CRC32 is
smg_comms_skeys_s...   22     Result : CRC32 := Init_Value;
smg_comms_skeys_s...   23     Value  : CRC32;
smg_comms_skeys_s...   24   begin
smg_comms_skeys_s...   25     -- process input character by character
smg_comms_skeys_s...   26     for C of S loop
smg_comms_skeys_s...   27       Value  := CRC32( Character'Pos( C ) );
smg_comms_skeys_s...   28       Result := Shift_Right(Result, 8) xor
smg_comms_skeys_s...   29                   Lookup( Value xor (Result and LSB_MASK));
smg_comms_skeys_s...   30     end loop;
smg_comms_skeys_s...   31     -- reflect result 
smg_comms_skeys_s...   32     Result := Result xor Xor_Out;
smg_comms_skeys_s...   33 
smg_comms_skeys_s...   34     return Result;
smg_comms_skeys_s...   35   end CRC;
smg_comms_skeys_s...   36 
smg_comms_skeys_s...   37   function CRC( Data: in Octet_Array ) return CRC32 is
smg_comms_skeys_s...   38     Result : CRC32 := Init_Value;
smg_comms_skeys_s...   39   begin
smg_comms_skeys_s...   40     -- process input octet by octet
smg_comms_skeys_s...   41     for C of Data loop
smg_comms_skeys_s...   42       Result := Shift_Right(Result, 8) xor
smg_comms_skeys_s...   43                   Lookup( CRC32(C) xor (Result and LSB_MASK));
smg_comms_skeys_s...   44     end loop;
smg_comms_skeys_s...   45     -- reflect result
smg_comms_skeys_s...   46     Result := Result xor Xor_Out;
smg_comms_skeys_s...   47 
smg_comms_skeys_s...   48     return Result;
smg_comms_skeys_s...   49   end CRC;
smg_comms_skeys_s...   50 
smg_comms_skeys_s...   51 end CRC32;
smg_comms_skeys_s...   52