From 3ff375493dcbce241d02e9429c3fb8c73f9a3560 Mon Sep 17 00:00:00 2001
From: Alex Clink <alexclink@gmail.com>
Date: Sun, 23 Jan 2022 16:20:30 -0500
Subject: [PATCH] Add Lehmer32 random number generator

---
 src/lehmer32.cr | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 src/lehmer32.cr

diff --git a/src/lehmer32.cr b/src/lehmer32.cr
new file mode 100644
index 0000000..4e068d0
--- /dev/null
+++ b/src/lehmer32.cr
@@ -0,0 +1,23 @@
+module PF
+  class Lehmer32
+    include Random
+
+    @state : UInt32
+
+    def initialize(@state = rand(type: UInt32))
+    end
+
+    def new_seed(n : Number)
+      @state = n.to_u32!
+    end
+
+    # Generate the next number in the squence
+    def next_u
+      @state &+= 0xe120fc15
+      tmp : UInt64 = @state.to_u64! &* 0x4a39b70d
+      m1 : UInt32 = ((tmp >> 32) ^ tmp).to_u32!
+      tmp = m1.to_u64! &* 0x12fad5c9
+      ((tmp >> 32) ^ tmp).to_u32!
+    end
+  end
+end