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/*
* Copyright 2008-2013 NVIDIA Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <thrust/detail/config.h>
#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
# pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
# pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
# pragma system_header
#endif // no system header
#include <thrust/detail/type_traits.h>
#include <limits>
//#include <stdint.h> // for intmax_t (not provided on MSVS 2005)
THRUST_NAMESPACE_BEGIN
namespace detail
{
// XXX good enough for the platforms we care about
typedef long long intmax_t;
template<typename Number>
struct is_signed
: integral_constant<bool, std::numeric_limits<Number>::is_signed>
{}; // end is_signed
template<typename T>
struct num_digits
: eval_if<
std::numeric_limits<T>::is_specialized,
integral_constant<
int,
std::numeric_limits<T>::digits
>,
integral_constant<
int,
sizeof(T) * std::numeric_limits<unsigned char>::digits - (is_signed<T>::value ? 1 : 0)
>
>::type
{}; // end num_digits
template<typename Integer>
struct integer_difference
//: eval_if<
// sizeof(Integer) >= sizeof(intmax_t),
// eval_if<
// is_signed<Integer>::value,
// identity_<Integer>,
// identity_<intmax_t>
// >,
// eval_if<
// sizeof(Integer) < sizeof(std::ptrdiff_t),
// identity_<std::ptrdiff_t>,
// identity_<intmax_t>
// >
// >
{
private:
// XXX workaround a pedantic warning in old versions of g++
// which complains about &&ing with a constant value
template<bool x, bool y>
struct and_
{
static const bool value = false;
};
template<bool y>
struct and_<true,y>
{
static const bool value = y;
};
public:
typedef typename
eval_if<
and_<
std::numeric_limits<Integer>::is_signed,
// digits is the number of no-sign bits
(!std::numeric_limits<Integer>::is_bounded || (int(std::numeric_limits<Integer>::digits) + 1 >= num_digits<intmax_t>::value))
>::value,
identity_<Integer>,
eval_if<
int(std::numeric_limits<Integer>::digits) + 1 < num_digits<signed int>::value,
identity_<signed int>,
eval_if<
int(std::numeric_limits<Integer>::digits) + 1 < num_digits<signed long>::value,
identity_<signed long>,
identity_<intmax_t>
>
>
>::type type;
}; // end integer_difference
template<typename Number>
struct numeric_difference
: eval_if<
is_integral<Number>::value,
integer_difference<Number>,
identity_<Number>
>
{}; // end numeric_difference
template<typename Number>
__host__ __device__
typename numeric_difference<Number>::type
numeric_distance(Number x, Number y)
{
typedef typename numeric_difference<Number>::type difference_type;
return difference_type(y) - difference_type(x);
} // end numeric_distance
} // end detail
THRUST_NAMESPACE_END
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