rand: add xoshiro256plusplus generator

CMakeLists.txt

@@ -479,8 +479,6 @@ list (
     quaternion.hpp
     rand/lcg.cpp
     rand/lcg.hpp
-    rand/xorshift.cpp
-    rand/xorshift.hpp
     rand/mwc64x.cpp
     rand/mwc64x.hpp
     rand/pcg.cpp
@@ -489,6 +487,10 @@ list (
     rand/rdrand.hpp
     rand/splitmix64.hpp
     rand/system.hpp
+    rand/xoshiro.cpp
+    rand/xoshiro.hpp
+    rand/xorshift.cpp
+    rand/xorshift.hpp
     random.cpp
     random.hpp
     range.cpp

rand/xoshiro.cpp

@@ -0,0 +1,128 @@
+/*
+ * Written in 2019 by David Blackman and Sebastiano Vigna (vigna@acm.org)
+ *
+ * To the extent possible under law, the author has dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide. This software is distributed without any warranty.
+ */
+
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2020, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "xoshiro.hpp"
+#include "splitmix64.hpp"
+
+#include "../bitwise.hpp"
+
+#include <algorithm>
+
+using cruft::rand::xoshiro256plusplus;
+
+
+///////////////////////////////////////////////////////////////////////////////
+xoshiro256plusplus::xoshiro256plusplus (u64 _seed)
+{
+    splitmix64 gen (_seed);
+    std::generate (
+        std::begin (m_state),
+        std::end   (m_state),
+        gen
+    );
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+u64
+xoshiro256plusplus::operator() (void)
+{
+    u64 const result = rotatel (m_state[0] + m_state[3], 23) + m_state[0];
+
+    u64 const t = m_state[1] << 17;
+
+    m_state[2] ^= m_state[0];
+    m_state[3] ^= m_state[1];
+    m_state[1] ^= m_state[2];
+    m_state[0] ^= m_state[3];
+
+    m_state[2] ^= t;
+
+    m_state[3] = rotatel (m_state[3], 45);
+
+    return result;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+xoshiro256plusplus::jump (void)
+{
+    static u64 constinit JUMP[] = {
+        0x180ec6d33cfd0aba,
+        0xd5a61266f0c9392c,
+        0xa9582618e03fc9aa,
+        0x39abdc4529b1661c
+    };
+
+    u64 s0 = 0;
+    u64 s1 = 0;
+    u64 s2 = 0;
+    u64 s3 = 0;
+
+    for (std::size_t i = 0; i < std::size (JUMP); ++i) {
+        for (int b = 0; b < 64; b++) {
+            if (JUMP[i] & u64 (1) << b) {
+                s0 ^= m_state[0];
+                s1 ^= m_state[1];
+                s2 ^= m_state[2];
+                s3 ^= m_state[3];
+            }
+            (*this) ();
+        }
+    }
+
+    m_state[0] = s0;
+    m_state[1] = s1;
+    m_state[2] = s2;
+    m_state[3] = s3;
+}
+
+
+//-----------------------------------------------------------------------------
+void
+xoshiro256plusplus::long_jump (void)
+{
+    static constinit u64 LONG_JUMP[] = {
+        0x76e15d3efefdcbbf,
+        0xc5004e441c522fb3,
+        0x77710069854ee241,
+        0x39109bb02acbe635
+    };
+
+    u64 s0 = 0;
+    u64 s1 = 0;
+    u64 s2 = 0;
+    u64 s3 = 0;
+
+    for (std::size_t i = 0; i < std::size (LONG_JUMP); ++i) {
+        for (int b = 0; b < 64; b++) {
+            if (LONG_JUMP[i] & u64{1} << b) {
+                s0 ^= m_state[0];
+                s1 ^= m_state[1];
+                s2 ^= m_state[2];
+                s3 ^= m_state[3];
+            }
+
+            (*this) ();
+        }
+    }
+
+    m_state[0] = s0;
+    m_state[1] = s1;
+    m_state[2] = s2;
+    m_state[3] = s3;
+}

rand/xoshiro.hpp

@@ -0,0 +1,51 @@
+/*
+ * Written in 2019 by David Blackman and Sebastiano Vigna (vigna@acm.org)
+ *
+ * To the extent possible under law, the author has dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide. This software is distributed without any warranty.
+ */
+
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2020, Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#pragma once
+
+#include "../std.hpp"
+
+#include <limits>
+
+
+///////////////////////////////////////////////////////////////////////////////
+namespace cruft::rand {
+    class xoshiro256plusplus {
+    public:
+        using result_type = u64;
+
+        xoshiro256plusplus (u64 seed);
+
+        static constexpr result_type min (void)
+        {
+            return std::numeric_limits<result_type>::min ();
+        }
+
+        static constexpr result_type max (void)
+        {
+            return std::numeric_limits<result_type>::max ();
+        }
+
+        result_type operator() (void);
+
+        void jump (void);
+        void long_jump (void);
+
+    private:
+        u64 m_state[4];
+    };
+}

test/rand/buckets.cpp

@@ -4,6 +4,7 @@
 #include "rand/pcg.hpp"
 #include "rand/rdrand.hpp"
 #include "rand/system.hpp"
+#include "rand/xoshiro.hpp"
 #include "rand/splitmix64.hpp"
 
 #include "tap.hpp"
@@ -51,6 +52,7 @@ main (int,char**)
     cruft::TAP::logger tap;
 
     test_buckets<cruft::rand::splitmix64> (tap, 0x1234u);
+    test_buckets<cruft::rand::xoshiro256plusplus> (tap, 0x1234u);
     test_buckets<cruft::rand::xorshift<uint32_t>> (tap, 0x1234u);
     test_buckets<cruft::rand::xorshift<uint64_t>> (tap, 0x1234u);
     test_buckets<cruft::rand::lcg_t> (tap, 0x1234u);