org.apache.lucene.codecs.bloom

Class MurmurHash2



  • public final class MurmurHash2
    extends HashFunction
    This is a very fast, non-cryptographic hash suitable for general hash-based lookup. See http://murmurhash.googlepages.com/ for more details.

    The C version of MurmurHash 2.0 found at that site was ported to Java by Andrzej Bialecki (ab at getopt org).

    The code from getopt.org was adapted by Mark Harwood in the form here as one of a pluggable choice of hashing functions as the core function had to be adapted to work with BytesRefs with offsets and lengths rather than raw byte arrays.

    • Method Detail

      • hash

        public static int hash(byte[] data,
                               int seed,
                               int offset,
                               int len)
      • hash32

        public static final int hash32(byte[] data,
                                       int offset,
                                       int len)
        Generates 32 bit hash from byte array with default seed value.
        Parameters:
        data - byte array to hash
        offset - the start position in the array to hash
        len - length of the array elements to hash
        Returns:
        32 bit hash of the given array
      • hash

        public final int hash(BytesRef br)
        Description copied from class: HashFunction
        Hashes the contents of the referenced bytes
        Specified by:
        hash in class HashFunction
        Parameters:
        br - the data to be hashed
        Returns:
        the hash of the bytes referenced by bytes.offset and length bytes.length