MXS-2247 Add support for random number generation to maxutils

Classes for xorshift and std random. Add a random number generator to Worker.

maxutils/maxbase/src/random.cc

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2019 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2022-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxbase/random.hh>
+
+namespace maxbase
+{
+
+static uint64_t splitmix(uint64_t& state)
+{
+    uint64_t z = (state += 0x9e3779b97f4a7c15);
+    z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
+    z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
+    return z ^ (z >> 31);
+}
+
+XorShiftRandom::XorShiftRandom(uint64_t seed)
+{
+    if (!seed)
+    {
+        std::random_device rdev;
+        while (!(seed = rdev()))
+        {
+        }
+    }
+    for (auto& s : m_state)
+    {
+        s = splitmix(seed);
+    }
+}
+
+StdTwisterRandom::StdTwisterRandom(uint64_t seed)
+{
+    std::random_device rdev;
+    m_twister_engine_32.seed(seed ? seed : rdev());
+    m_twister_engine_64.seed(seed ? seed : rdev());
+}
+
+std::mt19937_64& StdTwisterRandom::rnd_engine()
+{
+    return m_twister_engine_64;
+}
+}