mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
317 lines
11 KiB
C++
317 lines
11 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2015 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_RANDOM_UNIFORM_SMALLINT_HPP
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#define SPROUT_RANDOM_UNIFORM_SMALLINT_HPP
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#include <iosfwd>
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#include <istream>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/random/detail/signed_unsigned_tools.hpp>
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#include <sprout/random/random_result.hpp>
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#include <sprout/random/uniform_01.hpp>
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#include <sprout/random/results.hpp>
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#include <sprout/assert.hpp>
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namespace sprout {
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namespace random {
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//
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// uniform_smallint
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//
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template<typename IntType = int>
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class uniform_smallint {
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public:
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typedef IntType input_type;
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typedef IntType result_type;
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public:
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//
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// param_type
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//
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class param_type {
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public:
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typedef uniform_smallint distribution_type;
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private:
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IntType min_;
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IntType max_;
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public:
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SPROUT_CONSTEXPR param_type()
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: min_(0)
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, max_(sprout::numeric_limits<IntType>::max())
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{}
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param_type(param_type const&) = default;
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explicit SPROUT_CONSTEXPR param_type(IntType min_arg, IntType max_arg = sprout::numeric_limits<IntType>::max())
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: min_((SPROUT_ASSERT(min_arg <= max_arg), min_arg))
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, max_(max_arg)
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{}
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SPROUT_CONSTEXPR IntType a() const SPROUT_NOEXCEPT {
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return min_;
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}
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SPROUT_CONSTEXPR IntType b() const SPROUT_NOEXCEPT {
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return max_;
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}
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template<typename Elem, typename Traits>
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friend SPROUT_NON_CONSTEXPR std::basic_istream<Elem, Traits>& operator>>(
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std::basic_istream<Elem, Traits>& lhs,
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param_type& rhs
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)
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{
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IntType min;
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IntType max;
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if (lhs >> min >> std::ws >> max) {
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if (min <= max) {
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rhs.min_ = min;
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rhs.max_ = max;
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} else {
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lhs.setstate(std::ios_base::failbit);
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}
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}
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return lhs;
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}
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template<typename Elem, typename Traits>
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friend SPROUT_NON_CONSTEXPR std::basic_ostream<Elem, Traits>& operator<<(
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std::basic_ostream<Elem, Traits>& lhs,
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param_type const& rhs
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)
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{
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return lhs << rhs.min_ << " " << rhs.max_;
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}
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friend SPROUT_CONSTEXPR bool operator==(param_type const& lhs, param_type const& rhs) SPROUT_NOEXCEPT {
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return lhs.min_ == rhs.min_ && lhs.max_ == rhs.max_;
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}
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friend SPROUT_CONSTEXPR bool operator!=(param_type const& lhs, param_type const& rhs) SPROUT_NOEXCEPT {
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return !(lhs == rhs);
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}
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};
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private:
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IntType min_;
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IntType max_;
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private:
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template<typename Engine>
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SPROUT_CXX14_CONSTEXPR result_type generate(
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Engine& eng,
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std::true_type
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) const
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{
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typedef typename Engine::result_type base_result;
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typedef typename std::make_unsigned<base_result>::type base_unsigned;
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typedef typename std::make_unsigned<result_type>::type range_type;
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range_type range = sprout::random::detail::subtract<result_type>()(max_, min_);
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base_unsigned base_range = sprout::random::detail::subtract<result_type>()(eng.max(), eng.min());
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base_unsigned val = sprout::random::detail::subtract<base_result>()(static_cast<base_result>(eng()), eng.min());
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return range >= base_range
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? sprout::random::detail::add<range_type, result_type>()(static_cast<range_type>(val), min_)
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: sprout::random::detail::add<range_type, result_type>()(static_cast<range_type>(val % (static_cast<base_result>(range) + 1)), min_)
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;
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}
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template<typename Engine>
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SPROUT_CXX14_CONSTEXPR result_type generate(
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Engine& eng,
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std::false_type
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) const
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{
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typedef typename Engine::result_type base_result;
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typedef typename std::make_unsigned<result_type>::type range_type;
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range_type range = sprout::random::detail::subtract<result_type>()(max_, min_);
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base_result val = sprout::random::uniform_01<base_result>()(eng);
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range_type offset = static_cast<range_type>(val * (static_cast<base_result>(range) + 1));
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return offset > range
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? max_
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: sprout::random::detail::add<range_type, result_type>()(offset, min_)
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;
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}
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template<typename Engine, typename EngineResult, typename RangeType, typename BaseUnsigned>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate_true_2(
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Engine const&,
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EngineResult const& rnd,
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RangeType range,
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BaseUnsigned base_range,
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BaseUnsigned val
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) const
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{
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return range >= base_range
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? sprout::random::random_result<Engine, uniform_smallint>(
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sprout::random::detail::add<RangeType, result_type>()(static_cast<RangeType>(val), min_),
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sprout::random::next(rnd),
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*this
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)
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: sprout::random::random_result<Engine, uniform_smallint>(
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sprout::random::detail::add<RangeType, result_type>()(static_cast<RangeType>(val % (static_cast<BaseUnsigned>(range) + 1)), min_),
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sprout::random::next(rnd),
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*this
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)
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;
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}
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template<typename Engine, typename EngineResult, typename RangeType, typename BaseUnsigned>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate_true_1(
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Engine const& eng,
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EngineResult const& rnd,
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RangeType range,
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BaseUnsigned base_range
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) const
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{
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typedef typename Engine::result_type base_result;
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return generate_true_2(
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eng,
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rnd,
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range,
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base_range,
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BaseUnsigned(sprout::random::detail::subtract<base_result>()(sprout::random::result(rnd), eng.min()))
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);
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}
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template<typename Engine>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate(
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Engine const& eng,
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std::true_type
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) const
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{
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typedef typename Engine::result_type base_result;
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typedef typename std::make_unsigned<base_result>::type base_unsigned;
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typedef typename std::make_unsigned<result_type>::type range_type;
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return generate_true_1(
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eng,
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eng(),
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range_type(sprout::random::detail::subtract<result_type>()(max_, min_)),
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base_unsigned(sprout::random::detail::subtract<result_type>()(eng.max(), eng.min()))
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);
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}
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template<typename Engine, typename Random, typename RangeType>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate_false_2(
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Engine const&,
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Random const& rnd,
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RangeType range,
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RangeType offset
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) const
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{
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return offset > range
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? sprout::random::random_result<Engine, uniform_smallint>(
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max_,
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sprout::random::next(rnd).engine(),
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*this
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)
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: sprout::random::random_result<Engine, uniform_smallint>(
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sprout::random::detail::add<RangeType, result_type>()(offset, min_),
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sprout::random::next(rnd).engine(),
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*this
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)
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;
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}
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template<typename Engine, typename Random, typename RangeType>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate_false_1(
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Engine const& eng,
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Random const& rnd,
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RangeType range
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) const
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{
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typedef typename Engine::result_type base_result;
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return generate_false_2(
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eng,
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rnd,
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static_cast<RangeType>(sprout::random::detail::subtract<result_type>()(max_, min_)),
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static_cast<RangeType>(sprout::random::result(rnd) * (static_cast<base_result>(range) + 1))
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);
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}
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template<typename Engine>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> generate(
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Engine const& eng,
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std::false_type
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) const
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{
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typedef typename Engine::result_type base_result;
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typedef typename std::make_unsigned<result_type>::type range_type;
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return generate_false_1(
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eng,
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sprout::random::uniform_01<base_result>()(eng),
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static_cast<range_type>(sprout::random::detail::subtract<result_type>()(max_, min_))
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);
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}
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public:
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SPROUT_CONSTEXPR uniform_smallint() SPROUT_NOEXCEPT
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: min_(0)
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, max_(sprout::numeric_limits<IntType>::max())
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{}
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uniform_smallint(uniform_smallint const&) = default;
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explicit SPROUT_CONSTEXPR uniform_smallint(IntType min_arg, IntType max_arg = sprout::numeric_limits<IntType>::max())
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: min_((SPROUT_ASSERT(min_arg <= max_arg), min_arg))
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, max_(max_arg)
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{}
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explicit SPROUT_CONSTEXPR uniform_smallint(param_type const& parm) SPROUT_NOEXCEPT
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: min_(parm.a())
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, max_(parm.b())
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{}
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SPROUT_CONSTEXPR result_type a() const SPROUT_NOEXCEPT {
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return min_;
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}
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SPROUT_CONSTEXPR result_type b() const SPROUT_NOEXCEPT {
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return max_;
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}
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SPROUT_CONSTEXPR result_type min() const SPROUT_NOEXCEPT {
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return min_;
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}
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SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
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return max_;
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}
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SPROUT_CXX14_CONSTEXPR void reset() SPROUT_NOEXCEPT {}
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SPROUT_CONSTEXPR param_type param() const SPROUT_NOEXCEPT {
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return param_type(min_, max_);
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}
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SPROUT_CXX14_CONSTEXPR void param(param_type const& parm) {
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min_ = parm.a();
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max_ = parm.b();
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}
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template<typename Engine>
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SPROUT_CXX14_CONSTEXPR result_type operator()(Engine& eng) const {
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typedef typename Engine::result_type base_result;
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return generate(eng, typename std::is_integral<base_result>::type());
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}
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template<typename Engine>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> const operator()(Engine const& eng) const {
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typedef typename Engine::result_type base_result;
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return generate(eng, typename std::is_integral<base_result>::type());
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}
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template<typename Engine>
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SPROUT_CXX14_CONSTEXPR result_type operator()(Engine& eng, param_type const& parm) const {
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return uniform_smallint(parm)(eng);
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}
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template<typename Engine>
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SPROUT_CONSTEXPR sprout::random::random_result<Engine, uniform_smallint> const operator()(Engine const& eng, param_type const& parm) const {
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return uniform_smallint(parm)(eng);
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}
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template<typename Elem, typename Traits>
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friend SPROUT_NON_CONSTEXPR std::basic_istream<Elem, Traits>& operator>>(
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std::basic_istream<Elem, Traits>& lhs,
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uniform_smallint& rhs
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)
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{
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param_type parm;
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if (lhs >> parm) {
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rhs.param(parm);
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}
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return lhs;
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}
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template<typename Elem, typename Traits>
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friend SPROUT_NON_CONSTEXPR std::basic_ostream<Elem, Traits>& operator<<(
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std::basic_ostream<Elem, Traits>& lhs,
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uniform_smallint const& rhs
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)
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{
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return lhs << rhs.param();
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}
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friend SPROUT_CONSTEXPR bool operator==(uniform_smallint const& lhs, uniform_smallint const& rhs) SPROUT_NOEXCEPT {
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return lhs.param() == rhs.param();
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}
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friend SPROUT_CONSTEXPR bool operator!=(uniform_smallint const& lhs, uniform_smallint const& rhs) SPROUT_NOEXCEPT {
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return !(lhs == rhs);
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}
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};
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} // namespace random
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using sprout::random::uniform_smallint;
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} // namespace sprout
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#endif // #ifndef SPROUT_RANDOM_UNIFORM_SMALLINT_HPP
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