RFR JDK-6321472: Add CRC-32C API

[Andrej Golovnin]

Hi Staffan,

I'm not a reviewer but I have small remarks to the code style:

- the instance variable "crc" is declared bevor the class variables. I
would move it closer to the constructor.

- documentation comments should be used for the fields "crc" and
"CRC32C_POLY", e.g. instead of

     // Calculated CRC-32C value
     private int crc = 0xFFFFFFFF;

use this:

     /**
      * Calculated CRC-32C value
      */
     private int crc = 0xFFFFFFFF;


- the description of the implemented algorithm should use block comments
and should be moved to the top of the class, e.g.:

 public final class CRC32C implements Checksum {

     /*
      * This CRC-32C implementation uses the 'slicing-by-8' algorithm
described
      * in the paper "A Systematic Approach to Building High Performance
      * Software-Based CRC Generators" by Michael E. Kounavis and Frank L.
Berry,
      * Intel Research and Development
      */

  ...

In other case I get the filling that the Usafe class implements the
algorithm. :-)

- why some of the fields declared as "private transient final static"? I
would say "transient" is not needed here. Or am I missing something? And I
would use "private static final". I think this is the preferred way in the
JDK to declare a constant.

  61     private transient final static Unsafe UNSAFE = Unsafe.getUnsafe();
  62
  63     // Lookup tables
  64     private transient final static int[][] byteTables = new
int[8][256];
  65     private transient final static int[] byteTable;
  66     private transient final static int[] byteTable0 = byteTables[0];


Best regards,
Andrej Golovnin