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130 lines
3.3 KiB
130 lines
3.3 KiB
/* |
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* Copyright 2008-2012 NVIDIA Corporation |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#pragma once |
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#include <thrust/detail/type_traits.h> |
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#include <limits> |
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//#include <stdint.h> // for intmax_t (not provided on MSVS 2005) |
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namespace thrust |
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{ |
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namespace detail |
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{ |
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// XXX good enough for the platforms we care about |
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typedef long long intmax_t; |
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template<typename Number> |
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struct is_signed |
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: integral_constant<bool, std::numeric_limits<Number>::is_signed> |
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{}; // end is_signed |
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template<typename T> |
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struct num_digits |
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: eval_if< |
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std::numeric_limits<T>::is_specialized, |
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integral_constant< |
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int, |
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std::numeric_limits<T>::digits |
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>, |
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integral_constant< |
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int, |
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sizeof(T) * std::numeric_limits<unsigned char>::digits - (is_signed<T>::value ? 1 : 0) |
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> |
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>::type |
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{}; // end num_digits |
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template<typename Integer> |
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struct integer_difference |
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//: eval_if< |
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// sizeof(Integer) >= sizeof(intmax_t), |
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// eval_if< |
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// is_signed<Integer>::value, |
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// identity_<Integer>, |
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// identity_<intmax_t> |
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// >, |
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// eval_if< |
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// sizeof(Integer) < sizeof(std::ptrdiff_t), |
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// identity_<std::ptrdiff_t>, |
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// identity_<intmax_t> |
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// > |
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// > |
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{ |
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private: |
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// XXX workaround a pedantic warning in old versions of g++ |
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// which complains about &&ing with a constant value |
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template<bool x, bool y> |
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struct and_ |
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{ |
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static const bool value = false; |
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}; |
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template<bool y> |
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struct and_<true,y> |
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{ |
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static const bool value = y; |
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}; |
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public: |
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typedef typename |
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eval_if< |
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and_< |
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std::numeric_limits<Integer>::is_signed, |
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// digits is the number of no-sign bits |
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(!std::numeric_limits<Integer>::is_bounded || (int(std::numeric_limits<Integer>::digits) + 1 >= num_digits<intmax_t>::value)) |
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>::value, |
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identity_<Integer>, |
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eval_if< |
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int(std::numeric_limits<Integer>::digits) + 1 < num_digits<signed int>::value, |
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identity_<signed int>, |
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eval_if< |
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int(std::numeric_limits<Integer>::digits) + 1 < num_digits<signed long>::value, |
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identity_<signed long>, |
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identity_<intmax_t> |
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> |
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> |
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>::type type; |
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}; // end integer_difference |
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template<typename Number> |
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struct numeric_difference |
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: eval_if< |
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is_integral<Number>::value, |
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integer_difference<Number>, |
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identity_<Number> |
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> |
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{}; // end numeric_difference |
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template<typename Number> |
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__host__ __device__ |
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typename numeric_difference<Number>::type |
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numeric_distance(Number x, Number y) |
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{ |
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typedef typename numeric_difference<Number>::type difference_type; |
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return difference_type(y) - difference_type(x); |
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} // end numeric_distance |
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} // end detail |
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} // end thrust |
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