From 9ca6740db3f31b314aa3c58ad4599cc43f615629 Mon Sep 17 00:00:00 2001
From: Vinnie Falco <vinnie.falco@gmail.com>
Date: Tue, 13 Jan 2015 12:33:54 -0800
Subject: [PATCH] Add rngfill

---
 beast/random/rngfill.h | 69 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 beast/random/rngfill.h

diff --git a/beast/random/rngfill.h b/beast/random/rngfill.h
new file mode 100644
index 0000000000..7a7c1fe9e0
--- /dev/null
+++ b/beast/random/rngfill.h
@@ -0,0 +1,69 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2014, Vinnie Falco <vinnie.falco@gmail.com>
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef BEAST_RANDOM_RNGFILL_H_INCLUDED
+#define BEAST_RANDOM_RNGFILL_H_INCLUDED
+
+#include <array>
+#include <cstdint>
+#include <cstring>
+#include <beast/cxx14/type_traits.h> // <type_traits>
+
+namespace beast {
+
+template <class Generator>
+void
+rngfill (void* buffer, std::size_t bytes,
+    Generator& g)
+{
+    using result_type =
+        typename Generator::result_type;
+    while (bytes >= sizeof(result_type))
+    {
+        auto const v = g();
+        std::memcpy(buffer, &v, sizeof(v));
+        buffer = reinterpret_cast<
+            std::uint8_t*>(buffer) + sizeof(v);
+        bytes -= sizeof(v);
+    }
+    if (bytes > 0)
+    {
+        auto const v = g();
+        std::memcpy(buffer, &v, bytes);
+    }
+}
+
+template <class Generator, std::size_t N,
+    class = std::enable_if_t<
+        N % sizeof(typename Generator::result_type) == 0>>
+void
+rngfill (std::array<std::uint8_t, N>& a, Generator& g)
+{
+    using result_type =
+        typename Generator::result_type;
+    auto i = N / sizeof(result_type);
+    result_type* p =
+        reinterpret_cast<result_type*>(a.data());
+    while (i--)
+        *p++ = g();
+}
+
+} // beast
+
+#endif