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eucrypt_ch14_crc32      1 ------------------------------------------------------------------------------
eucrypt_ch14_crc32      2 ------------------------------------------------------------------------------
eucrypt_ch14_crc32      3 -- This file is part of 'CRC32'                                             --
eucrypt_ch14_crc32      4 --                                                                          --
eucrypt_ch14_crc32      5 -- You do not have, nor can you ever acquire the right to use, copy or      --
eucrypt_ch14_crc32      6 -- distribute this software ; Should you use this software for any purpose, --
eucrypt_ch14_crc32      7 -- or copy and distribute it to anyone or in any manner, you are breaking   --
eucrypt_ch14_crc32      8 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
eucrypt_ch14_crc32      9 -- continue doing so for the indefinite future. In any case, please         --
eucrypt_ch14_crc32     10 -- always : read and understand any software ; verify any PGP signatures    --
eucrypt_ch14_crc32     11 -- that you use - for any purpose.                                          --
eucrypt_ch14_crc32     12 --                                                                          --
eucrypt_ch14_crc32     13 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
eucrypt_ch14_crc32     14 ------------------------------------------------------------------------------
eucrypt_ch14_crc32     15 ------------------------------------------------------------------------------
eucrypt_ch14_crc32     16 
eucrypt_ch14_crc32     17   -- CRC32 implementation
eucrypt_ch14_crc32     18   -- S.MG, 2018
eucrypt_ch14_crc32     19 
eucrypt_ch14_crc32     20 package body CRC32 is
eucrypt_ch14_crc32     21   function CRC( S: in String ) return CRC32 is
eucrypt_ch14_crc32     22     Result : CRC32 := Init_Value;
eucrypt_ch14_crc32     23     Value  : CRC32;
eucrypt_ch14_crc32     24   begin
eucrypt_ch14_crc32     25     -- process input character by character
eucrypt_ch14_crc32     26     for C of S loop
eucrypt_ch14_crc32     27       Value  := CRC32( Character'Pos( C ) );
eucrypt_ch14_crc32     28       Result := Shift_Right(Result, 8) xor
eucrypt_ch14_crc32     29                   Lookup( Value xor (Result and LSB_MASK));
eucrypt_ch14_crc32     30     end loop;
eucrypt_ch14_crc32     31     -- reflect result 
eucrypt_ch14_crc32     32     Result := Result xor Xor_Out;
eucrypt_ch14_crc32     33 
eucrypt_ch14_crc32     34     return Result;
eucrypt_ch14_crc32     35   end CRC;
eucrypt_ch14_crc32     36 
eucrypt_ch14_crc32     37   function CRC( Data: in Octet_Array ) return CRC32 is
eucrypt_ch14_crc32     38     Result : CRC32 := Init_Value;
eucrypt_ch14_crc32     39   begin
eucrypt_ch14_crc32     40     -- process input octet by octet
eucrypt_ch14_crc32     41     for C of Data loop
eucrypt_ch14_crc32     42       Result := Shift_Right(Result, 8) xor
eucrypt_ch14_crc32     43                   Lookup( CRC32(C) xor (Result and LSB_MASK));
eucrypt_ch14_crc32     44     end loop;
eucrypt_ch14_crc32     45     -- reflect result
eucrypt_ch14_crc32     46     Result := Result xor Xor_Out;
eucrypt_ch14_crc32     47 
eucrypt_ch14_crc32     48     return Result;
eucrypt_ch14_crc32     49   end CRC;
eucrypt_ch14_crc32     50 
eucrypt_ch14_crc32     51 end CRC32;
eucrypt_ch14_crc32     52