Contents

# encoding: UTF-8
#
# = FNV_Hash_1a_64.rb -- Persistent Ruby Object Store
#
# Copyright (c) 2019 by Chris Schlaeger <[e-mail]>
#
# MIT License
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

module PEROBS

  # This is an implementation of the Fowler Noll Vo hashing algorithm in the
  # 1a variant for 64 bit hash values.
  # https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
  class FNV_Hash_1a_64

    @@OFFSET = 14695981039346656037
    @@PRIME = 1099511628211
    @@MASK = 2**64 - 1

    def self.digest(item)
      hash = @@OFFSET

      item.to_s.each_byte do |byte|
        hash ^= byte
        hash *= @@PRIME
        hash &= @@MASK
      end

      hash
    end

  end

end

Version data entries

6 entries across 6 versions & 1 rubygems

Version	Path
perobs-4.6.0	lib/perobs/FNV_Hash_1a_64.rb
perobs-4.5.0	lib/perobs/FNV_Hash_1a_64.rb
perobs-4.4.0	lib/perobs/FNV_Hash_1a_64.rb
perobs-4.3.0	lib/perobs/FNV_Hash_1a_64.rb
perobs-4.2.0	lib/perobs/FNV_Hash_1a_64.rb
perobs-4.1.0	lib/perobs/FNV_Hash_1a_64.rb