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// -*- C++ -*-
//===-- execution_impl.h --------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _PSTL_EXECUTION_IMPL_H
#define _PSTL_EXECUTION_IMPL_H
#include <iterator>
#include <type_traits>
#include "execution_defs.h"
namespace __pstl
{
namespace __internal
{
using namespace __pstl::execution;
/* predicate */
template <typename _Tp>
std::false_type __lazy_and(_Tp, std::false_type)
{
return std::false_type{};
}
template <typename _Tp>
inline _Tp
__lazy_and(_Tp __a, std::true_type)
{
return __a;
}
template <typename _Tp>
std::true_type __lazy_or(_Tp, std::true_type)
{
return std::true_type{};
}
template <typename _Tp>
inline _Tp
__lazy_or(_Tp __a, std::false_type)
{
return __a;
}
/* iterator */
template <typename _IteratorType, typename... _OtherIteratorTypes>
struct __is_random_access_iterator
{
static constexpr bool value = __internal::__is_random_access_iterator<_IteratorType>::value &&
__internal::__is_random_access_iterator<_OtherIteratorTypes...>::value;
typedef std::integral_constant<bool, value> type;
};
template <typename _IteratorType>
struct __is_random_access_iterator<_IteratorType>
: std::is_same<typename std::iterator_traits<_IteratorType>::iterator_category, std::random_access_iterator_tag>
{
};
/* policy */
template <typename _Policy>
struct __policy_traits
{
};
template <>
struct __policy_traits<sequenced_policy>
{
typedef std::false_type allow_parallel;
typedef std::false_type allow_unsequenced;
typedef std::false_type allow_vector;
};
template <>
struct __policy_traits<unsequenced_policy>
{
typedef std::false_type allow_parallel;
typedef std::true_type allow_unsequenced;
typedef std::true_type allow_vector;
};
template <>
struct __policy_traits<parallel_policy>
{
typedef std::true_type allow_parallel;
typedef std::false_type allow_unsequenced;
typedef std::false_type allow_vector;
};
template <>
struct __policy_traits<parallel_unsequenced_policy>
{
typedef std::true_type allow_parallel;
typedef std::true_type allow_unsequenced;
typedef std::true_type allow_vector;
};
template <typename _ExecutionPolicy>
using __collector_t =
typename __internal::__policy_traits<typename std::decay<_ExecutionPolicy>::type>::__collector_type;
template <typename _ExecutionPolicy>
using __allow_vector =
typename __internal::__policy_traits<typename std::decay<_ExecutionPolicy>::type>::__allow_vector;
template <typename _ExecutionPolicy>
using __allow_unsequenced =
typename __internal::__policy_traits<typename std::decay<_ExecutionPolicy>::type>::__allow_unsequenced;
template <typename _ExecutionPolicy>
using __allow_parallel =
typename __internal::__policy_traits<typename std::decay<_ExecutionPolicy>::type>::__allow_parallel;
template <typename _ExecutionPolicy, typename... _IteratorTypes>
auto
__is_vectorization_preferred(_ExecutionPolicy&& __exec)
-> decltype(__internal::__lazy_and(__exec.__allow_vector(),
typename __internal::__is_random_access_iterator<_IteratorTypes...>::type()))
{
return __internal::__lazy_and(__exec.__allow_vector(),
typename __internal::__is_random_access_iterator<_IteratorTypes...>::type());
}
template <typename _ExecutionPolicy, typename... _IteratorTypes>
auto
__is_parallelization_preferred(_ExecutionPolicy&& __exec)
-> decltype(__internal::__lazy_and(__exec.__allow_parallel(),
typename __internal::__is_random_access_iterator<_IteratorTypes...>::type()))
{
return __internal::__lazy_and(__exec.__allow_parallel(),
typename __internal::__is_random_access_iterator<_IteratorTypes...>::type());
}
template <typename policy, typename... _IteratorTypes>
struct __prefer_unsequenced_tag
{
static constexpr bool value = __internal::__allow_unsequenced<policy>::value &&
__internal::__is_random_access_iterator<_IteratorTypes...>::value;
typedef std::integral_constant<bool, value> type;
};
template <typename policy, typename... _IteratorTypes>
struct __prefer_parallel_tag
{
static constexpr bool value = __internal::__allow_parallel<policy>::value &&
__internal::__is_random_access_iterator<_IteratorTypes...>::value;
typedef std::integral_constant<bool, value> type;
};
} // namespace __internal
} // namespace __pstl
#endif /* _PSTL_EXECUTION_IMPL_H */
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