From 230630b45b88977e891cefa6029d021f4aa9e6bb Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Tue, 5 Nov 2013 17:39:11 +0900
Subject: [PATCH] add C++14 constexpr version: random generator

---
 sprout/random/additive_combine.hpp       |  8 ++++++++
 sprout/random/inversive_congruential.hpp |  5 +++++
 sprout/random/linear_congruential.hpp    |  9 ++++++++-
 sprout/random/linear_feedback_shift.hpp  |  4 ++++
 sprout/random/shuffle_order.hpp          | 17 ++++++++++++++++-
 sprout/random/xor_combine.hpp            |  3 +++
 6 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/sprout/random/additive_combine.hpp b/sprout/random/additive_combine.hpp
index ac411b87..cb4b21d2 100644
--- a/sprout/random/additive_combine.hpp
+++ b/sprout/random/additive_combine.hpp
@@ -82,6 +82,14 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return base1_type::modulus - 1;
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				result_type val1 = static_cast<result_type>(mlcg1_());
+				result_type val2 = static_cast<result_type>(mlcg2_());
+				return val2 < val1
+					? val1 - val2
+					: val1 - val2 + base1_type::modulus - 1
+					;
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<additive_combine_engine> const operator()() const {
 				return generate(mlcg1_(), mlcg2_());
 			}
diff --git a/sprout/random/inversive_congruential.hpp b/sprout/random/inversive_congruential.hpp
index 8699acce..b8ee8825 100644
--- a/sprout/random/inversive_congruential.hpp
+++ b/sprout/random/inversive_congruential.hpp
@@ -79,6 +79,11 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return static_max();
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				typedef sprout::random::detail::const_mod<IntType, p> do_mod;
+				x_ = do_mod::mult_add(a, do_mod::invert(x_), b);
+				return x_;
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<inversive_congruential_engine> const operator()() const {
 				typedef sprout::random::detail::const_mod<IntType, p> do_mod;
 				return generate(do_mod::mult_add(a, do_mod::invert(x_), b));
diff --git a/sprout/random/linear_congruential.hpp b/sprout/random/linear_congruential.hpp
index 07d7ea1f..338fb383 100644
--- a/sprout/random/linear_congruential.hpp
+++ b/sprout/random/linear_congruential.hpp
@@ -82,6 +82,10 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return static_max();
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				x_ = sprout::random::detail::const_mod<UIntType, m>::mult_add(a, x_, c);
+				return x_;
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<linear_congruential_engine> const operator()() const {
 				return generate(sprout::random::detail::const_mod<UIntType, m>::mult_add(a, x_, c));
 			}
@@ -167,7 +171,7 @@ namespace sprout {
 			template<typename LcfResult>
 			SPROUT_CONSTEXPR sprout::random::random_result<rand48> generate(LcfResult const& lcf_result) const {
 				return sprout::random::random_result<rand48>(
-					lcf_result.result() >> 17,
+					static_cast<result_type>(lcf_result.result()) >> 17,
 					rand48(lcf_result.engine(), private_construct_t())
 					);
 			}
@@ -184,6 +188,9 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const {
 				return static_max();
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				return static_cast<result_type>(static_cast<result_type>(lcf_()) >> 17);
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<rand48> const operator()() const {
 				return generate(lcf_());
 			}
diff --git a/sprout/random/linear_feedback_shift.hpp b/sprout/random/linear_feedback_shift.hpp
index 67657b19..599d6d95 100644
--- a/sprout/random/linear_feedback_shift.hpp
+++ b/sprout/random/linear_feedback_shift.hpp
@@ -78,6 +78,10 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return static_max();
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				 x_ = ((x_ & ((wordmask() << (w - k)) & wordmask())) << s) ^ ((((x_ << q) ^ x_) & wordmask()) >> (k - s));
+				 return x_;
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<linear_feedback_shift_engine> const operator()() const {
 				return generate(((x_ & ((wordmask() << (w - k)) & wordmask())) << s) ^ ((((x_ << q) ^ x_) & wordmask()) >> (k - s)));
 			}
diff --git a/sprout/random/shuffle_order.hpp b/sprout/random/shuffle_order.hpp
index 58165774..d1923373 100644
--- a/sprout/random/shuffle_order.hpp
+++ b/sprout/random/shuffle_order.hpp
@@ -124,7 +124,7 @@ namespace sprout {
 						: sprout::math::less(brange, sprout::numeric_limits<BaseUnsigned>::max() / k) ? BaseUnsigned(k * off / (brange + 1))
 						: sprout::math::less(brange, sprout::numeric_limits<std::uintmax_t>::max() / k)
 							? static_cast<BaseUnsigned>(static_cast<std::uintmax_t>(off) * k / (static_cast<std::uintmax_t>(brange) + 1))
-						//: static_cast<BaseUnsigned>(sprout::random::detail::muldiv(off, k, static_cast<std::uintmax_t>(brange) + 1)) // ???
+//						: static_cast<BaseUnsigned>(sprout::random::detail::muldiv(off, k, static_cast<std::uintmax_t>(brange) + 1)) // ???
 						: (SPROUT_ASSERT_MSG(0, "Sorry, not implemented."), sprout::random::random_result<shuffle_order_engine>())
 					);
 			}
@@ -144,6 +144,21 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return rng_.max();
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				typedef typename std::make_unsigned<result_type>::type base_unsigned;
+				base_unsigned const brange = sprout::random::detail::subtract<result_type>()(max(), min());
+				base_unsigned const off = sprout::random::detail::subtract<result_type>()(y_, min());
+				base_unsigned j = k == 1 ? base_unsigned(0)
+					: sprout::math::less(brange, sprout::numeric_limits<base_unsigned>::max() / k) ? base_unsigned(k * off / (brange + 1))
+					: sprout::math::less(brange, sprout::numeric_limits<std::uintmax_t>::max() / k)
+						? static_cast<base_unsigned>(static_cast<std::uintmax_t>(off) * k / (static_cast<std::uintmax_t>(brange) + 1))
+//					: static_cast<base_unsigned>(sprout::random::detail::muldiv(off, k, static_cast<std::uintmax_t>(brange) + 1)) // ???
+					: (SPROUT_ASSERT_MSG(0, "Sorry, not implemented."), base_unsigned(0))
+					;
+				y_ = v_[j];
+				v_[j] = static_cast<result_type>(rng_());
+				return y_;
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<shuffle_order_engine> const operator()() const {
 				typedef typename std::make_unsigned<result_type>::type base_unsigned;
 				return generate(
diff --git a/sprout/random/xor_combine.hpp b/sprout/random/xor_combine.hpp
index b678474f..e5dcf165 100644
--- a/sprout/random/xor_combine.hpp
+++ b/sprout/random/xor_combine.hpp
@@ -70,6 +70,9 @@ namespace sprout {
 			SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
 				return NS_SSCRISK_CEL_OR_SPROUT::max(rng1_.max(), rng2_.max());
 			}
+			SPROUT_CXX14_CONSTEXPR result_type operator()() {
+				return (static_cast<result_type>(rng1_()) << s1) ^ (static_cast<result_type>(rng2_()) << s2);
+			}
 			SPROUT_CONSTEXPR sprout::random::random_result<xor_combine_engine> const operator()() const {
 				return generate(rng1_(), rng2_());
 			}