From 82d3c36ebdeaeb2f52e120b5fe86ea9f9b15afb0 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Thu, 12 Nov 2020 11:07:14 +1000
Subject: [PATCH] rand/xoshiro: simplify state initialisation from seed_seq

---
 rand/xoshiro.cpp | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/rand/xoshiro.cpp b/rand/xoshiro.cpp
index 204324d7..07937dc6 100644
--- a/rand/xoshiro.cpp
+++ b/rand/xoshiro.cpp
@@ -39,18 +39,11 @@ xoshiro256plusplus::xoshiro256plusplus (u64 _seed)
 //-----------------------------------------------------------------------------
 xoshiro256plusplus::xoshiro256plusplus (std::seed_seq &seq)
 {
-    std::generate (
-        std::begin (m_state),
-        std::end   (m_state),
-        [&] (void) {
-            u64 parts[2];
-            seq.generate (
-                std::begin (parts),
-                std::end   (parts)
-            );
-            return parts[0] << 4 | parts[1];
-        }
-    );
+    u32 parts[8];
+    seq.generate (std::begin (parts), std::end (parts));
+
+    for (int i = 0; i < std::ssize (m_state); ++i)
+        m_state[i] = u64 (parts[i * 2]) << 32 | parts[i * 2 + 1];
 }