From 3500d0d49cbfc5b23a6e25175ed68a5622ad9767 Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Fri, 22 Jun 2012 22:56:25 +0900
Subject: [PATCH] add popcount, clz, ctz

---
 sprout/bit/clz.hpp             | 52 ++++++++++++++++++++++++++++++++++
 sprout/bit/ctz.hpp             | 46 ++++++++++++++++++++++++++++++
 sprout/bit/operation.hpp       |  9 ++++++
 sprout/bit/popcount.hpp        | 47 ++++++++++++++++++++++++++++++
 sprout/bitset/bitset.hpp       | 46 ++++++------------------------
 sprout/config/auto_config.hpp  |  9 ++++++
 sprout/config/compiler/gcc.hpp |  4 +++
 sprout/config/config.hpp       |  6 ++++
 8 files changed, 181 insertions(+), 38 deletions(-)
 create mode 100644 sprout/bit/clz.hpp
 create mode 100644 sprout/bit/ctz.hpp
 create mode 100644 sprout/bit/operation.hpp
 create mode 100644 sprout/bit/popcount.hpp

diff --git a/sprout/bit/clz.hpp b/sprout/bit/clz.hpp
new file mode 100644
index 00000000..b7685f5f
--- /dev/null
+++ b/sprout/bit/clz.hpp
@@ -0,0 +1,52 @@
+#ifndef SPROUT_BIT_CLZ_HPP
+#define SPROUT_BIT_CLZ_HPP
+
+#include <climits>
+#include <type_traits>
+#include <sprout/config.hpp>
+
+namespace sprout {
+	namespace detail {
+#	if SPROUT_USE_BUILTIN_BIT_OPERATION
+		inline SPROUT_CONSTEXPR int
+		clz(unsigned n) {
+			return __builtin_clz(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		clz(unsigned long n) {
+			return __builtin_clzl(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		clz(unsigned long long n) {
+			return __builtin_clzll(n);
+		}
+#	endif
+		template<typename T>
+		inline SPROUT_CONSTEXPR int
+		clz_impl(T n, T m = T(1) << (CHAR_BIT * sizeof(T) - 1)) {
+			return m == 0 || n & m ? 0
+				: 1 + sprout::detail::clz_impl(n, static_cast<T>(m >> 1))
+				;
+		}
+		template<typename T, typename sprout::enabler_if<std::is_unsigned<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		clz(T n) {
+			return sprout::detail::clz_impl(static_cast<T>(n));
+		}
+		template<typename T, typename sprout::enabler_if<std::is_signed<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		clz(T n) {
+			return sprout::detail::clz(static_cast<typename std::make_unsigned<T>::type>(n));
+		}
+	}	// namespace detail
+	//
+	// clz
+	//
+	template<typename T, typename sprout::enabler_if<std::is_integral<T>::value>::type = sprout::enabler>
+	inline SPROUT_CONSTEXPR int
+	clz(T n) {
+		return sprout::detail::clz(n);
+	}
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_BIT_CLZ_HPP
diff --git a/sprout/bit/ctz.hpp b/sprout/bit/ctz.hpp
new file mode 100644
index 00000000..06eb7622
--- /dev/null
+++ b/sprout/bit/ctz.hpp
@@ -0,0 +1,46 @@
+#ifndef SPROUT_BIT_CTZ_HPP
+#define SPROUT_BIT_CTZ_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+
+namespace sprout {
+	namespace detail {
+#	if SPROUT_USE_BUILTIN_BIT_OPERATION
+		inline SPROUT_CONSTEXPR int
+		ctz(unsigned n) {
+			return __builtin_ctz(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		ctz(unsigned long n) {
+			return __builtin_ctzl(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		ctz(unsigned long long n) {
+			return __builtin_ctzll(n);
+		}
+#	endif
+		template<typename T, typename sprout::enabler_if<std::is_unsigned<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		ctz(T n) {
+			return n & 1 ? 0
+				: 1 + sprout::detail::ctz(static_cast<T>(n >> 1))
+				;
+		}
+		template<typename T, typename sprout::enabler_if<std::is_signed<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		ctz(T n) {
+			return sprout::detail::ctz(static_cast<typename std::make_unsigned<T>::type>(n));
+		}
+	}	// namespace detail
+	//
+	// ctz
+	//
+	template<typename T, typename sprout::enabler_if<std::is_integral<T>::value>::type = sprout::enabler>
+	inline SPROUT_CONSTEXPR int
+	ctz(T n) {
+		return sprout::detail::ctz(n);
+	}
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_BIT_CTZ_HPP
diff --git a/sprout/bit/operation.hpp b/sprout/bit/operation.hpp
new file mode 100644
index 00000000..397de650
--- /dev/null
+++ b/sprout/bit/operation.hpp
@@ -0,0 +1,9 @@
+#ifndef SPROUT_BIT_OPERATION_HPP
+#define SPROUT_BIT_OPERATION_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/bit/popcount.hpp>
+#include <sprout/bit/clz.hpp>
+#include <sprout/bit/ctz.hpp>
+
+#endif	// #ifndef SPROUT_BIT_OPERATION_HPP
diff --git a/sprout/bit/popcount.hpp b/sprout/bit/popcount.hpp
new file mode 100644
index 00000000..7067735d
--- /dev/null
+++ b/sprout/bit/popcount.hpp
@@ -0,0 +1,47 @@
+#ifndef SPROUT_BIT_POPCOUNT_HPP
+#define SPROUT_BIT_POPCOUNT_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
+
+namespace sprout {
+	namespace detail {
+#	if SPROUT_USE_BUILTIN_BIT_OPERATION
+		inline SPROUT_CONSTEXPR int
+		popcount(unsigned n) {
+			return __builtin_popcount(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		popcount(unsigned long n) {
+			return __builtin_popcountl(n);
+		}
+		inline SPROUT_CONSTEXPR int
+		popcount(unsigned long long n) {
+			return __builtin_popcountll(n);
+		}
+#	endif
+		template<typename T, typename sprout::enabler_if<std::is_unsigned<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		popcount(T n) {
+			return n == 0 ? 0
+				: 1 + sprout::detail::popcount(static_cast<T>(n & (n - 1)))
+				;
+		}
+		template<typename T, typename sprout::enabler_if<std::is_signed<T>::value>::type = sprout::enabler>
+		inline SPROUT_CONSTEXPR int
+		popcount(T n) {
+			return sprout::detail::popcount(static_cast<typename std::make_unsigned<T>::type>(n));
+		}
+	}	// namespace detail
+	//
+	// popcount
+	//
+	template<typename T, typename sprout::enabler_if<std::is_integral<T>::value>::type = sprout::enabler>
+	inline SPROUT_CONSTEXPR int
+	popcount(T n) {
+		return sprout::detail::popcount(n);
+	}
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_BIT_POPCOUNT_HPP
diff --git a/sprout/bitset/bitset.hpp b/sprout/bitset/bitset.hpp
index fbdebda4..ede9e689 100644
--- a/sprout/bitset/bitset.hpp
+++ b/sprout/bitset/bitset.hpp
@@ -15,42 +15,12 @@
 #include <sprout/algorithm/fixed/fill.hpp>
 #include <sprout/operation/fixed/set.hpp>
 #include <sprout/utility/forward.hpp>
+#include <sprout/bit/operation.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 #include HDR_NUMERIC_SSCRISK_CEL_OR_SPROUT
 #include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	namespace detail {
-		template<typename T>
-		inline SPROUT_CONSTEXPR std::size_t
-		popcount(T n) {
-			return n == 0 ? 0
-				: 1 + sprout::detail::popcount(n & (n - 1))
-				;
-		}
-
-		template<typename T>
-		inline SPROUT_CONSTEXPR std::size_t
-		clz_impl(T n, T m = 1 << (CHAR_BIT * sizeof(T))) {
-			return m == 0 || n & m ? 0
-				: 1 + sprout::detail::clz_impl(n, m >> 1)
-				;
-		}
-		template<typename T>
-		inline SPROUT_CONSTEXPR std::size_t
-		clz(T n) {
-			return sprout::detail::clz_impl(n >> 1);
-		}
-
-		template<typename T>
-		inline SPROUT_CONSTEXPR std::size_t
-		ctz(T n) {
-			return n & 1 ? 0
-				: 1 + sprout::detail::ctz(n >> 1)
-				;
-		}
-	}	// namespace detail
-
 	namespace detail {
 		struct base_bitset_from_words_construct_tag {};
 
@@ -92,7 +62,7 @@ namespace sprout {
 			public:
 				SPROUT_CONSTEXPR std::size_t
 				operator()(std::size_t lhs, std::size_t rhs) const SPROUT_NOEXCEPT {
-					return lhs + sprout::detail::popcount(rhs);
+					return lhs + sprout::popcount(rhs);
 				}
 			};
 		public:
@@ -123,7 +93,7 @@ namespace sprout {
 			{
 				return first == last ? not_found
 					: *first != static_cast<word_type>(0)
-						? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::detail::ctz(*first)
+						? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::ctz(*first)
 					: find_first_impl(not_found, first + 1, last, i + 1)
 					;
 			}
@@ -135,14 +105,14 @@ namespace sprout {
 			{
 				return first == last ? not_found
 					: *first != static_cast<word_type>(0)
-						? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::detail::ctz(*first)
+						? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::ctz(*first)
 					: find_next_impl_2(not_found, first + 1, last)
 					;
 			}
 			SPROUT_CONSTEXPR std::size_t
 			find_next_impl_1(std::size_t not_found, std::size_t i, word_type thisword) const SPROUT_NOEXCEPT {
 				return thisword != static_cast<word_type>(0)
-					? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::detail::ctz(thisword)
+					? i * (CHAR_BIT * sizeof(unsigned long)) + sprout::ctz(thisword)
 					: find_next_impl_2(not_found, begin() + (i + 1), end(), i + 1)
 					;
 			}
@@ -512,7 +482,7 @@ namespace sprout {
 		private:
 			SPROUT_CONSTEXPR std::size_t
 			find_next_impl(std::size_t prev, std::size_t not_found, word_type x) const SPROUT_NOEXCEPT {
-				return x != 0 ? sprout::detail::ctz(x) + prev
+				return x != 0 ? sprout::ctz(x) + prev
 					: not_found
 					;
 			}
@@ -641,7 +611,7 @@ namespace sprout {
 			}
 			SPROUT_CONSTEXPR std::size_t
 			do_count() const SPROUT_NOEXCEPT {
-				return sprout::detail::popcount(w_);
+				return sprout::popcount(w_);
 			}
 
 			SPROUT_CONSTEXPR unsigned long
@@ -655,7 +625,7 @@ namespace sprout {
 
 			SPROUT_CONSTEXPR std::size_t
 			find_first(std::size_t not_found) const SPROUT_NOEXCEPT {
-				return w_ != 0 ? sprout::detail::ctz(w_)
+				return w_ != 0 ? sprout::ctz(w_)
 					: not_found
 					;
 			}
diff --git a/sprout/config/auto_config.hpp b/sprout/config/auto_config.hpp
index 472d6daa..2d81945d 100644
--- a/sprout/config/auto_config.hpp
+++ b/sprout/config/auto_config.hpp
@@ -61,6 +61,15 @@
 #	endif	// #ifdef SPROUT_HAS_CONSTEXPR_CMATH_FUNCTION
 #endif	// #ifndef SPROUT_CONFIG_DISABLE_BUILTIN_CMATH_FUNCTION
 
+//
+// SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+//
+#ifndef SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+#	ifndef SPROUT_HAS_CONSTEXPR_BIT_OPERATION
+#		define SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+#	endif	// #ifdef SPROUT_HAS_CONSTEXPR_BIT_OPERATION
+#endif	// #ifndef SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+
 //
 // SPROUT_CONFIG_DISABLE_SUPPORT_TEMPORARY_CONTAINER_ITERATION
 // SPROUT_CONFIG_SUPPORT_TEMPORARY_CONTAINER_ITERATION
diff --git a/sprout/config/compiler/gcc.hpp b/sprout/config/compiler/gcc.hpp
index 6df80508..43839099 100644
--- a/sprout/config/compiler/gcc.hpp
+++ b/sprout/config/compiler/gcc.hpp
@@ -25,4 +25,8 @@
 #	define SPROUT_HAS_CONSTEXPR_CMATH_FUNCTION
 #endif
 
+#if ((__GNUC__ >= 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)) && defined(__GXX_EXPERIMENTAL_CXX0X__))
+#	define SPROUT_HAS_CONSTEXPR_BIT_OPERATION
+#endif
+
 #endif	// #ifndef SPROUT_CONFIG_COMPILER_GCC_HPP
diff --git a/sprout/config/config.hpp b/sprout/config/config.hpp
index 8ec3cf2b..4b50d643 100644
--- a/sprout/config/config.hpp
+++ b/sprout/config/config.hpp
@@ -69,6 +69,12 @@
 #	define SPROUT_USE_BUILTIN_CMATH_FUNCTION 0
 #endif	// #ifndef SPROUT_CONFIG_DISABLE_BUILTIN_CMATH_FUNCTION
 
+#ifndef SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+#	define SPROUT_USE_BUILTIN_BIT_OPERATION 1
+#else	// #ifndef SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+#	define SPROUT_USE_BUILTIN_BIT_OPERATION 0
+#endif	// #ifndef SPROUT_CONFIG_DISABLE_BUILTIN_BIT_OPERATION
+
 #ifndef SPROUT_CONFIG_DISABLE_SUPPORT_TEMPORARY_CONTAINER_ITERATION
 #	define SPROUT_USE_INDEX_ITERATOR_IMPLEMENTATION 1
 #else	// #ifndef SPROUT_CONFIG_DISABLE_SUPPORT_TEMPORARY_CONTAINER_ITERATION