Sha256: 1057dca97922cc0e3bfbcc04d9beeeb546ac61c212f29664554e33996932d3ef
Contents?: true
Size: 995 Bytes
Versions: 8
Compression:
Stored size: 995 Bytes
Contents
# frozen_string_literal: true
require "murmurhash3"
require_relative "./hashing"
class VariantAssigner
attr_reader :key
def initialize(key)
md5 = Hashing.hash_unit(key.to_s)
@key = MurmurHash3::V32.str_hash(md5)
@normalizer = 1.0 / 0xffffffff
end
def probability(seed_hi, seed_lo)
buffer = Array.new
put_uint32(buffer, seed_lo)
put_uint32(buffer, seed_hi)
put_uint32(buffer, key)
hash = MurmurHash3::V32.str_hash(buffer.pack("C*"))
prob = (hash & 0xffffffff) * @normalizer
prob
end
def self.choose_variant(split, prob)
sum = 0
split.each_with_index do |s, i|
sum += s
return i if prob < sum
end
split.count - 1
end
def assign(split, seed_hi, seed_lo)
prob = probability(seed_hi, seed_lo)
self.class.choose_variant(split, prob)
end
def put_uint32(buffer, x)
buffer << (x & 0xff)
buffer << ((x >> 8) & 0xff)
buffer << ((x >> 16) & 0xff)
buffer << ((x >> 24) & 0xff)
end
end
Version data entries
8 entries across 8 versions & 1 rubygems