1 files changed, 65 insertions, 0 deletions
diff --git a/boost/beast/core/detail/pcg.hpp b/boost/beast/core/detail/pcg.hpp
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+++ b/boost/beast/core/detail/pcg.hpp
@@ -0,0 +1,65 @@
+//
+// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_CORE_DETAIL_PCG_HPP
+#define BOOST_BEAST_CORE_DETAIL_PCG_HPP
+
+#include <boost/core/ignore_unused.hpp>
+#include <cstdint>
+#include <random>
+
+namespace boost {
+namespace beast {
+namespace detail {
+
+class pcg
+{
+    std::uint64_t state_ = 0;
+    std::uint64_t increment_;
+
+public:
+    using result_type = std::uint32_t;
+
+    // Initialize the generator.
+    // There are no restrictions on the input values.
+    pcg(
+        std::uint64_t seed,
+        std::uint64_t stream)
+    {
+        // increment must be odd
+        increment_ = 2 * stream + 1;
+        boost::ignore_unused((*this)());
+        state_ += seed;
+        boost::ignore_unused((*this)());
+    }
+
+    std::uint32_t
+    operator()()
+    {
+        std::uint64_t const p = state_;
+        state_ = p *
+            6364136223846793005ULL +
+            increment_;
+        std::uint32_t const x =
+            static_cast<std::uint32_t>(
+            ((p >> 18) ^ p) >> 27);
+        std::uint32_t const r = p >> 59;
+    #ifdef BOOST_MSVC
+        return _rotr(x, r);
+    #else
+        return (x >> r) | (x << ((1 + ~r) & 31));
+    #endif
+    }
+};
+
+} // detail
+} // beast
+} // boost
+
+#endif