0.1.1

.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover
+
+# The directory Mix downloads your dependencies sources to.
+/deps
+
+# Where 3rd-party dependencies like ExDoc output generated docs.
+/doc
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez

LICENSE

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+Copyright 2017 Wil Wade.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

README.md

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+# RandPCG
+
+A random number generator using the [PCG](http://www.pcg-random.org/) algorithm.
+
+Documentation: https://hexdocs.pm/rand_pcg/
+
+## Installation
+
+  1. Add `rand_pcg` to your list of dependencies in `mix.exs`:
+
+    ```elixir
+    def deps do
+      [{:rand_pcg, "~> 0.1.1"}]
+    end
+    ```
+
+  2. If you are using the GenServer option, ensure `rand_pcg` is started before
+   your application:
+
+    ```elixir
+    def application do
+      [applications: [:rand_pcg]]
+    end
+    ```
+
+## Examples
+
+### GenServer Option
+
+Ensure the service is running if not included as an application:
+`RandPCG.start_link`
+
+#### Get Some Random
+
+```elixir
+# Random 32 bit integer
+RandPCG.random()
+
+# Random 32 bit based float
+RandPCG.random(:float)
+
+# n Random 32 bit integers
+RandPCG.random(n)
+
+# Random nth of an enumerable
+list = [:a, :b, :c]
+RandPCG.random(list)
+
+# Random integer x where min <= x <= max
+RandPCG.random(min, max)
+
+# n random integers x where min <= x <= max
+RandPCG.random(min, max, n)
+```
+
+#### Set State
+
+```elixir
+state = %RandPCG.State{seed: 234532454323451, inc: 1}
+RandPCG.state(state)
+```
+
+#### Note
+
+The initial seed is based on `:os.system_time(:micro_seconds)`
+
+### Without running the GenServer
+
+You will have to maintain your own state of the random number generator.
+
+#### Random 32 bit Integer
+
+```elixir
+state = RandPCG.gen_state()
+random_int_32 = RandPCG.xsh_rr(state)
+state = advance(state)
+```
+
+If you do not advance the state, you will receive the same random number.
+
+#### Random Integer in a Range
+
+```elixir
+state = RandPCG.gen_state()
+min = 1
+max = 10
+random_1_10_inclusive = RandPCG.rand_int(min, max, state)
+state = advance(state)
+```
+
+`RandPCG.gen_state` initial seed is based on `:os.system_time(:micro_seconds)`
+
+## References
+
+- [PCG Random Number Generator Homepage](http://www.pcg-random.org/)
+- [PCG Basic C Implementation](https://github.com/imneme/pcg-c-basic)
+- [PCG Go Implementation](https://github.com/dgryski/go-pcgr) was also helpful

config/config.exs

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+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Mix.Config module.
+use Mix.Config
+
+# This configuration is loaded before any dependency and is restricted
+# to this project. If another project depends on this project, this
+# file won't be loaded nor affect the parent project. For this reason,
+# if you want to provide default values for your application for
+# 3rd-party users, it should be done in your "mix.exs" file.
+
+# You can configure for your application as:
+#
+#     config :rand_pcg, key: :value
+#
+# And access this configuration in your application as:
+#
+#     Application.get_env(:rand_pcg, :key)
+#
+# Or configure a 3rd-party app:
+#
+#     config :logger, level: :info
+#
+
+# It is also possible to import configuration files, relative to this
+# directory. For example, you can emulate configuration per environment
+# by uncommenting the line below and defining dev.exs, test.exs and such.
+# Configuration from the imported file will override the ones defined
+# here (which is why it is important to import them last).
+#
+#     import_config "#{Mix.env}.exs"

lib/helpers.ex

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+defmodule RandPCG.Helpers do
+  @moduledoc """
+  Bitwise helpers
+  """
+  use Bitwise, only_operators: true
+
+  @mask32 0xFFFFFFFF
+
+  @spec rotate_right_32(RandPCG.uint64, RandPCG.uint64) :: RandPCG.uint32
+  def rotate_right_32(v, rotate) do
+    rotate = rotate &&& 31
+    ((v >>> rotate) ||| (v <<< (-rotate &&& 31))) &&& @mask32
+  end
+end