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2406b28e64
The codebase is filled with includes that are unused, and which thus can be removed. At the same time, the files often do not include all headers that contain the definitions used in those files. This change uses clang-format and clang-tidy to clean up the includes, with minor manual intervention to ensure the code compiles on all platforms.
211 lines
6.3 KiB
C++
211 lines
6.3 KiB
C++
//------------------------------------------------------------------------------
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/*
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This file is part of rippled: https://github.com/ripple/rippled
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Copyright (c) 2012, 2013 Ripple Labs Inc.
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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//==============================================================================
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#ifndef RIPPLE_BASICS_RANDOM_H_INCLUDED
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#define RIPPLE_BASICS_RANDOM_H_INCLUDED
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#include <xrpl/beast/utility/instrumentation.h>
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#include <xrpl/beast/xor_shift_engine.h>
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#include <cstddef>
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#include <cstdint>
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#include <limits>
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#include <mutex>
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#include <random>
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#include <type_traits>
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namespace ripple {
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#ifndef __INTELLISENSE__
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static_assert(
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std::is_integral<beast::xor_shift_engine::result_type>::value &&
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std::is_unsigned<beast::xor_shift_engine::result_type>::value,
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"The Ripple default PRNG engine must return an unsigned integral type.");
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static_assert(
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std::numeric_limits<beast::xor_shift_engine::result_type>::max() >=
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std::numeric_limits<std::uint64_t>::max(),
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"The Ripple default PRNG engine return must be at least 64 bits wide.");
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#endif
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namespace detail {
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// Determines if a type can be called like an Engine
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template <class Engine, class Result = typename Engine::result_type>
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using is_engine = std::is_invocable_r<Result, Engine>;
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} // namespace detail
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/** Return the default random engine.
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This engine is guaranteed to be deterministic, but by
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default will be randomly seeded. It is NOT cryptographically
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secure and MUST NOT be used to generate randomness that
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will be used for keys, secure cookies, IVs, padding, etc.
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Each thread gets its own instance of the engine which
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will be randomly seeded.
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*/
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inline beast::xor_shift_engine&
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default_prng()
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{
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// This is used to seed the thread-specific PRNGs on demand
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static beast::xor_shift_engine seeder = [] {
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std::random_device rng;
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std::uniform_int_distribution<std::uint64_t> distribution{1};
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return beast::xor_shift_engine(distribution(rng));
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}();
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// This protects the seeder
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static std::mutex m;
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// The thread-specific PRNGs:
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thread_local beast::xor_shift_engine engine = [] {
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std::uint64_t seed;
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{
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std::lock_guard lk(m);
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std::uniform_int_distribution<std::uint64_t> distribution{1};
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seed = distribution(seeder);
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}
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return beast::xor_shift_engine{seed};
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}();
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return engine;
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}
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/** Return a uniformly distributed random integer.
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@param min The smallest value to return. If not specified
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the value defaults to 0.
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@param max The largest value to return. If not specified
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the value defaults to the largest value that
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can be represented.
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The randomness is generated by the specified engine (or
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the default engine if one is not specified). The result
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is cryptographically secure only when the engine passed
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into the function is cryptographically secure.
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@note The range is always a closed interval, so calling
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rand_int(-5, 15) can return any integer in the
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closed interval [-5, 15]; similarly, calling
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rand_int(7) can return any integer in the closed
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interval [0, 7].
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*/
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/** @{ */
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template <class Engine, class Integral>
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std::enable_if_t<
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std::is_integral<Integral>::value && detail::is_engine<Engine>::value,
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Integral>
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rand_int(Engine& engine, Integral min, Integral max)
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{
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XRPL_ASSERT(max > min, "ripple::rand_int : max over min inputs");
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// This should have no state and constructing it should
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// be very cheap. If that turns out not to be the case
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// it could be hand-optimized.
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return std::uniform_int_distribution<Integral>(min, max)(engine);
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}
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template <class Integral>
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std::enable_if_t<std::is_integral<Integral>::value, Integral>
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rand_int(Integral min, Integral max)
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{
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return rand_int(default_prng(), min, max);
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}
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template <class Engine, class Integral>
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std::enable_if_t<
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std::is_integral<Integral>::value && detail::is_engine<Engine>::value,
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Integral>
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rand_int(Engine& engine, Integral max)
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{
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return rand_int(engine, Integral(0), max);
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}
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template <class Integral>
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std::enable_if_t<std::is_integral<Integral>::value, Integral>
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rand_int(Integral max)
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{
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return rand_int(default_prng(), max);
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}
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template <class Integral, class Engine>
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std::enable_if_t<
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std::is_integral<Integral>::value && detail::is_engine<Engine>::value,
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Integral>
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rand_int(Engine& engine)
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{
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return rand_int(engine, std::numeric_limits<Integral>::max());
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}
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template <class Integral = int>
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std::enable_if_t<std::is_integral<Integral>::value, Integral>
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rand_int()
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{
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return rand_int(default_prng(), std::numeric_limits<Integral>::max());
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}
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/** @} */
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/** Return a random byte */
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/** @{ */
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template <class Byte, class Engine>
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std::enable_if_t<
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(std::is_same<Byte, unsigned char>::value ||
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std::is_same<Byte, std::uint8_t>::value) &&
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detail::is_engine<Engine>::value,
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Byte>
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rand_byte(Engine& engine)
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{
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return static_cast<Byte>(rand_int<Engine, std::uint32_t>(
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engine,
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std::numeric_limits<Byte>::min(),
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std::numeric_limits<Byte>::max()));
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}
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template <class Byte = std::uint8_t>
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std::enable_if_t<
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(std::is_same<Byte, unsigned char>::value ||
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std::is_same<Byte, std::uint8_t>::value),
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Byte>
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rand_byte()
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{
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return rand_byte<Byte>(default_prng());
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}
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/** @} */
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/** Return a random boolean value */
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/** @{ */
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template <class Engine>
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inline bool
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rand_bool(Engine& engine)
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{
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return rand_int(engine, 1) == 1;
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}
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inline bool
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rand_bool()
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{
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return rand_bool(default_prng());
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}
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/** @} */
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} // namespace ripple
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#endif // RIPPLE_BASICS_RANDOM_H_INCLUDED
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