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concurrentqueue/benchmarks/tbb/scheduler_utility.h

134 lines
5.2 KiB
C++

/*
Copyright 2005-2014 Intel Corporation. All Rights Reserved.
This file is part of Threading Building Blocks. Threading Building Blocks is free software;
you can redistribute it and/or modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation. Threading Building Blocks is
distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details. You should have received a copy of
the GNU General Public License along with Threading Building Blocks; if not, write to the
Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
As a special exception, you may use this file as part of a free software library without
restriction. Specifically, if other files instantiate templates or use macros or inline
functions from this file, or you compile this file and link it with other files to produce
an executable, this file does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however invalidate any other
reasons why the executable file might be covered by the GNU General Public License.
*/
#ifndef _TBB_scheduler_utility_H
#define _TBB_scheduler_utility_H
#include "scheduler.h"
namespace tbb {
namespace internal {
//------------------------------------------------------------------------
// auto_empty_task
//------------------------------------------------------------------------
//! Smart holder for the empty task class with automatic destruction
class auto_empty_task {
task* my_task;
generic_scheduler* my_scheduler;
public:
auto_empty_task ( __TBB_CONTEXT_ARG(generic_scheduler *s, task_group_context* context) )
: my_task( new(&s->allocate_task(sizeof(empty_task), __TBB_CONTEXT_ARG(NULL, context))) empty_task )
, my_scheduler(s)
{}
// empty_task has trivial destructor, so there's no need to call it.
~auto_empty_task () { my_scheduler->free_task<small_local_task>(*my_task); }
operator task& () { return *my_task; }
task* operator & () { return my_task; }
task_prefix& prefix () { return my_task->prefix(); }
}; // class auto_empty_task
//------------------------------------------------------------------------
// fast_reverse_vector
//------------------------------------------------------------------------
//! Vector that grows without reallocations, and stores items in the reverse order.
/** Requires to initialize its first segment with a preallocated memory chunk
(usually it is static array or an array allocated on the stack).
The second template parameter specifies maximal number of segments. Each next
segment is twice as large as the previous one. **/
template<typename T, size_t max_segments = 16>
class fast_reverse_vector
{
public:
fast_reverse_vector ( T* initial_segment, size_t segment_size )
: m_cur_segment(initial_segment)
, m_cur_segment_size(segment_size)
, m_pos(segment_size)
, m_num_segments(0)
, m_size(0)
{
__TBB_ASSERT ( initial_segment && segment_size, "Nonempty initial segment must be supplied");
}
~fast_reverse_vector ()
{
for ( size_t i = 1; i < m_num_segments; ++i )
NFS_Free( m_segments[i] );
}
size_t size () const { return m_size + m_cur_segment_size - m_pos; }
void push_back ( const T& val )
{
if ( !m_pos ) {
if ( !m_num_segments ) m_segments[m_num_segments++] = m_cur_segment;
m_size += m_cur_segment_size;
m_cur_segment_size *= 2;
m_pos = m_cur_segment_size;
m_segments[m_num_segments++] = m_cur_segment = (T*)NFS_Allocate( m_cur_segment_size, sizeof(T), NULL );
__TBB_ASSERT ( m_num_segments < max_segments, "Maximal capacity exceeded" );
}
m_cur_segment[--m_pos] = val;
}
//! Copies the contents of the vector into the dst array.
/** Can only be used when T is a POD type, as copying does not invoke copy constructors. **/
void copy_memory ( T* dst ) const
{
size_t sz = m_cur_segment_size - m_pos;
memcpy( dst, m_cur_segment + m_pos, sz * sizeof(T) );
dst += sz;
sz = m_cur_segment_size / 2;
for ( long i = (long)m_num_segments - 2; i >= 0; --i ) {
memcpy( dst, m_segments[i], sz * sizeof(T) );
dst += sz;
sz /= 2;
}
}
protected:
//! The current (not completely filled) segment
T *m_cur_segment;
//! Capacity of m_cur_segment
size_t m_cur_segment_size;
//! Insertion position in m_cur_segment
size_t m_pos;
//! Array of segments (has fixed size specified by the second template parameter)
T *m_segments[max_segments];
//! Number of segments (the size of m_segments)
size_t m_num_segments;
//! Number of items in the segments in m_segments
size_t m_size;
}; // class fast_reverse_vector
} // namespace internal
} // namespace tbb
#endif /* _TBB_scheduler_utility_H */