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// -*- C++ -*-
//===-- parallel_backend_utils.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_parallel_backend_utils_H
#define __PSTL_parallel_backend_utils_H
#include <iterator>
#include <utility>
#include "utils.h"
namespace __pstl
{
namespace __par_backend
{
//! Destroy sequence [xs,xe)
struct __serial_destroy
{
template <typename _RandomAccessIterator>
void
operator()(_RandomAccessIterator __zs, _RandomAccessIterator __ze)
{
typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _ValueType;
while (__zs != __ze)
{
--__ze;
(*__ze).~_ValueType();
}
}
};
//! Merge sequences [__xs,__xe) and [__ys,__ye) to output sequence [__zs,(__xe-__xs)+(__ye-__ys)), using std::move
template <class _MoveValues, class _MoveSequences>
struct __serial_move_merge
{
const std::size_t _M_nmerge;
_MoveValues _M_move_values;
_MoveSequences _M_move_sequences;
explicit __serial_move_merge(std::size_t __nmerge, _MoveValues __move_values, _MoveSequences __move_sequences)
: _M_nmerge(__nmerge), _M_move_values(__move_values), _M_move_sequences(__move_sequences)
{
}
template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare>
void
operator()(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys,
_RandomAccessIterator2 __ye, _RandomAccessIterator3 __zs, _Compare __comp)
{
auto __n = _M_nmerge;
__PSTL_ASSERT(__n > 0);
if (__xs != __xe)
{
if (__ys != __ye)
{
for (;;)
{
if (__comp(*__ys, *__xs))
{
_M_move_values(__ys, __zs);
++__zs, --__n;
if (++__ys == __ye)
{
break;
}
else if (__n == 0)
{
__zs = _M_move_sequences(__ys, __ye, __zs);
break;
}
else
{
}
}
else
{
_M_move_values(__xs, __zs);
++__zs, --__n;
if (++__xs == __xe)
{
_M_move_sequences(__ys, __ye, __zs);
return;
}
else if (__n == 0)
{
__zs = _M_move_sequences(__xs, __xe, __zs);
_M_move_sequences(__ys, __ye, __zs);
return;
}
else
{
}
}
}
}
__ys = __xs;
__ye = __xe;
}
_M_move_sequences(__ys, __ye, __zs);
}
};
template <typename _RandomAccessIterator1, typename _OutputIterator>
void
__init_buf(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _OutputIterator __zs, bool __bMove)
{
const _OutputIterator __ze = __zs + (__xe - __xs);
typedef typename std::iterator_traits<_OutputIterator>::value_type _ValueType;
if (__bMove)
{
// Initialize the temporary buffer and move keys to it.
for (; __zs != __ze; ++__xs, ++__zs)
new (&*__zs) _ValueType(std::move(*__xs));
}
else
{
// Initialize the temporary buffer
for (; __zs != __ze; ++__zs)
new (&*__zs) _ValueType;
}
}
// TODO is this actually used anywhere?
template <typename _Buf>
class __stack
{
typedef typename std::iterator_traits<decltype(_Buf(0).get())>::value_type _ValueType;
typedef typename std::iterator_traits<_ValueType*>::difference_type _DifferenceType;
_Buf _M_buf;
_ValueType* _M_ptr;
_DifferenceType _M_maxsize;
__stack(const __stack&) = delete;
void
operator=(const __stack&) = delete;
public:
__stack(_DifferenceType __max_size) : _M_buf(__max_size), _M_maxsize(__max_size) { _M_ptr = _M_buf.get(); }
~__stack()
{
__PSTL_ASSERT(size() <= _M_maxsize);
while (!empty())
pop();
}
const _Buf&
buffer() const
{
return _M_buf;
}
size_t
size() const
{
__PSTL_ASSERT(_M_ptr - _M_buf.get() <= _M_maxsize);
__PSTL_ASSERT(_M_ptr - _M_buf.get() >= 0);
return _M_ptr - _M_buf.get();
}
bool
empty() const
{
__PSTL_ASSERT(_M_ptr >= _M_buf.get());
return _M_ptr == _M_buf.get();
}
void
push(const _ValueType& __v)
{
__PSTL_ASSERT(size() < _M_maxsize);
new (_M_ptr) _ValueType(__v);
++_M_ptr;
}
const _ValueType&
top() const
{
return *(_M_ptr - 1);
}
void
pop()
{
__PSTL_ASSERT(_M_ptr > _M_buf.get());
--_M_ptr;
(*_M_ptr).~_ValueType();
}
};
} // namespace __par_backend
} // namespace __pstl
#endif /* __PSTL_parallel_backend_utils_H */
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