mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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69 lines
2.1 KiB
C++
69 lines
2.1 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 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_DETAIL_SIGNED_UNSIGNED_TOOLS_HPP
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#define SPROUT_RANDOM_DETAIL_SIGNED_UNSIGNED_TOOLS_HPP
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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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namespace sprout {
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namespace random {
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namespace detail {
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template<typename T, bool B = sprout::numeric_limits<T>::is_signed>
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struct subtract {};
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template<typename T>
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struct subtract<T, false> {
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public:
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typedef T result_type;
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public:
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SPROUT_CONSTEXPR result_type operator()(T x, T y) const {
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return x - y;
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}
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};
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template<typename T>
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struct subtract<T, true> {
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public:
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typedef typename std::make_unsigned<T>::type result_type;
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public:
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SPROUT_CONSTEXPR result_type operator()(T x, T y) const {
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return y >= 0 ? result_type(x) - result_type(y)
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: x >= 0 ? result_type(x) + result_type(-(y + 1)) + 1
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: result_type(x - y)
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;
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}
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};
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template<typename T1, typename T2, bool B = sprout::numeric_limits<T2>::is_signed>
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struct add {};
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template<typename T1, typename T2>
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struct add<T1, T2, false> {
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public:
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typedef T2 result_type;
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public:
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SPROUT_CONSTEXPR result_type operator()(T1 x, T2 y) const {
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return T2(x) + y;
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}
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};
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template<typename T1, typename T2>
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struct add<T1, T2, true> {
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public:
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typedef T2 result_type;
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public:
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SPROUT_CONSTEXPR result_type operator()(T1 x, T2 y) const {
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return y >= 0 ? T2(x) + y
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: x >= T1(-(y + 1)) ? T2(x - T1(-(y + 1)) - 1)
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: T2(x) + y
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;
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}
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};
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} // namespace detail
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} // namespace random
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} // namespace sprout
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#endif // SPROUT_RANDOM_DETAIL_SIGNED_UNSIGNED_TOOLS_HPP
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