Rearrange sources

include/xrpl/crypto/csprng.h

@@ -0,0 +1,96 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    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 RIPPLE_CRYPTO_RANDOM_H_INCLUDED
+#define RIPPLE_CRYPTO_RANDOM_H_INCLUDED
+
+#include <mutex>
+#include <string>
+#include <type_traits>
+
+namespace ripple {
+
+/** A cryptographically secure random number engine
+
+    The engine is thread-safe (it uses a lock to serialize
+    access) and will, automatically, mix in some randomness
+    from std::random_device.
+
+    Meets the requirements of UniformRandomNumberEngine
+*/
+class csprng_engine
+{
+private:
+    std::mutex mutex_;
+
+public:
+    using result_type = std::uint64_t;
+
+    csprng_engine(csprng_engine const&) = delete;
+    csprng_engine&
+    operator=(csprng_engine const&) = delete;
+
+    csprng_engine(csprng_engine&&) = delete;
+    csprng_engine&
+    operator=(csprng_engine&&) = delete;
+
+    csprng_engine();
+    ~csprng_engine();
+
+    /** Mix entropy into the pool */
+    void
+    mix_entropy(void* buffer = nullptr, std::size_t count = 0);
+
+    /** Generate a random integer */
+    result_type
+    operator()();
+
+    /** Fill a buffer with the requested amount of random data */
+    void
+    operator()(void* ptr, std::size_t count);
+
+    /* The smallest possible value that can be returned */
+    static constexpr result_type
+    min()
+    {
+        return std::numeric_limits<result_type>::min();
+    }
+
+    /* The largest possible value that can be returned */
+    static constexpr result_type
+    max()
+    {
+        return std::numeric_limits<result_type>::max();
+    }
+};
+
+/** The default cryptographically secure PRNG
+
+    Use this when you need to generate random numbers or
+    data that will be used for encryption or passed into
+    cryptographic routines.
+
+    This meets the requirements of UniformRandomNumberEngine
+*/
+csprng_engine&
+crypto_prng();
+
+}  // namespace ripple
+
+#endif