Class OggCrc


  • public class OggCrc
    extends java.lang.Object
    Calculates the CRC checksum for Ogg packets.

    Ogg uses the same generator polynomial as ethernet, although with an unreflected alg and an init/final of 0, not 0xffffffff.

    Version:
    $Revision: 1.2 $
    Author:
    Jim Lawrence, helloNetwork.com, Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static int[] crc_lookup
      CRC checksum lookup table
    • Constructor Summary

      Constructors 
      Constructor Description
      OggCrc()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static int checksum​(int crc, byte[] data, int offset, int length)
      Calculates the checksum on the given data, from the give offset and for the given length, using the given initial value.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • crc_lookup

        private static int[] crc_lookup
        CRC checksum lookup table
    • Constructor Detail

      • OggCrc

        public OggCrc()
    • Method Detail

      • checksum

        public static int checksum​(int crc,
                                   byte[] data,
                                   int offset,
                                   int length)
        Calculates the checksum on the given data, from the give offset and for the given length, using the given initial value. This allows on to calculate the checksum iteratively, by reinjecting the last returned value as the initial value when the function is called for the next data chunk. The initial value should be 0 for the first iteration.
        Parameters:
        crc - - the initial value
        data - - the data
        offset - - the offset at which to start calculating the checksum.
        length - - the length of data over which to calculate the checksum.
        Returns:
        the checksum.