154 lines
5.1 KiB
C++
154 lines
5.1 KiB
C++
//----------------------------------------------------------------------------
|
|
/// @file indirect.hpp
|
|
/// @brief Indirect algorithm
|
|
///
|
|
/// @author Copyright (c) 2016 Francisco Jose Tapia (fjtapia@gmail.com )\n
|
|
/// Distributed under the Boost Software License, Version 1.0.\n
|
|
/// ( See accompanying file LICENSE_1_0.txt or copy at
|
|
/// http://www.boost.org/LICENSE_1_0.txt )
|
|
/// @version 0.1
|
|
///
|
|
/// @remarks
|
|
//-----------------------------------------------------------------------------
|
|
#ifndef __BOOST_SORT_PARALLEL_COMMON_INDIRECT_HPP
|
|
#define __BOOST_SORT_PARALLEL_COMMON_INDIRECT_HPP
|
|
|
|
//#include <boost/sort/common/atomic.hpp>
|
|
#include <boost/sort/common/util/traits.hpp>
|
|
#include <functional>
|
|
#include <iterator>
|
|
#include <type_traits>
|
|
#include <vector>
|
|
|
|
namespace boost
|
|
{
|
|
namespace sort
|
|
{
|
|
namespace common
|
|
{
|
|
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
/// @struct less_ptr_no_null
|
|
///
|
|
/// @remarks this is the comparison object for pointers. Compare the objects
|
|
/// pointed by the iterators
|
|
//---------------------------------------------------------------------------
|
|
template<class Iter_t, class Compare = util::compare_iter<Iter_t> >
|
|
struct less_ptr_no_null
|
|
{
|
|
//----------------------------- Variables -----------------------
|
|
Compare comp; // comparison object of the elements pointed by Iter_t
|
|
|
|
//------------------------------------------------------------------------
|
|
// function : less_ptr_no_null
|
|
/// @brief constructor from a Compare object
|
|
/// @param C1 : comparison object
|
|
//-----------------------------------------------------------------------
|
|
less_ptr_no_null(Compare C1 = Compare()): comp(C1) { };
|
|
|
|
//------------------------------------------------------------------------
|
|
// function : operator ( )
|
|
/// @brief Make the comparison of the objects pointed by T1 and T2, using
|
|
// the internal comp
|
|
//
|
|
/// @param T1 : first iterator
|
|
/// @param T2 : second iterator
|
|
/// @return bool result of the comparison
|
|
//-----------------------------------------------------------------------
|
|
bool operator( )(Iter_t T1, Iter_t T2) const
|
|
{
|
|
return comp(*T1, *T2);
|
|
};
|
|
};
|
|
//
|
|
//-----------------------------------------------------------------------------
|
|
// function : create_index
|
|
/// @brief From a vector of objects, create a vector of iterators to
|
|
/// the objects
|
|
///
|
|
/// @param first : iterator to the first element of the range
|
|
/// @param last : iterator to the element after the last of the range
|
|
/// @param index : vector where store the iterators
|
|
//-----------------------------------------------------------------------------
|
|
template<class Iter_t>
|
|
static void create_index(Iter_t first, Iter_t last, std::vector<Iter_t> &index)
|
|
{
|
|
auto nelem = last - first;
|
|
assert(nelem >= 0);
|
|
index.clear();
|
|
index.reserve(nelem);
|
|
for (; first != last; ++first) index.push_back(first);
|
|
};
|
|
//
|
|
//-----------------------------------------------------------------------------
|
|
// function : sort_index
|
|
/// @brief This function transform a logical sort of the elements in the index
|
|
/// in a physical sort
|
|
//
|
|
/// @param global_first : iterator to the first element of the data
|
|
/// @param [in] index : vector of the iterators
|
|
//-----------------------------------------------------------------------------
|
|
template<class Iter_t>
|
|
static void sort_index(Iter_t global_first, std::vector<Iter_t> &index)
|
|
{
|
|
typedef util::value_iter<Iter_t> value_t;
|
|
|
|
size_t pos_dest = 0;
|
|
size_t pos_src = 0;
|
|
size_t pos_in_vector = 0;
|
|
size_t nelem = index.size();
|
|
Iter_t it_dest, it_src;
|
|
|
|
while (pos_in_vector < nelem)
|
|
{
|
|
while (pos_in_vector < nelem and
|
|
(size_t(index[pos_in_vector] - global_first)) == pos_in_vector)
|
|
{
|
|
++pos_in_vector;
|
|
};
|
|
|
|
if (pos_in_vector == nelem) return;
|
|
pos_dest = pos_src = pos_in_vector;
|
|
it_dest = global_first + pos_dest;
|
|
value_t Aux = std::move(*it_dest);
|
|
|
|
while ((pos_src = (size_t(index[pos_dest] - global_first)))
|
|
!= pos_in_vector)
|
|
{
|
|
index[pos_dest] = it_dest;
|
|
it_src = global_first + pos_src;
|
|
*it_dest = std::move(*it_src);
|
|
it_dest = it_src;
|
|
pos_dest = pos_src;
|
|
};
|
|
|
|
*it_dest = std::move(Aux);
|
|
index[pos_dest] = it_dest;
|
|
++pos_in_vector;
|
|
};
|
|
};
|
|
|
|
template<class func, class Iter_t, class Compare = compare_iter<Iter_t> >
|
|
static void indirect_sort(func method, Iter_t first, Iter_t last, Compare comp)
|
|
{
|
|
auto nelem = (last - first);
|
|
assert(nelem >= 0);
|
|
if (nelem < 2) return;
|
|
std::vector<Iter_t> index;
|
|
index.reserve((size_t) nelem);
|
|
create_index(first, last, index);
|
|
less_ptr_no_null<Iter_t, Compare> index_comp(comp);
|
|
method(index.begin(), index.end(), index_comp);
|
|
sort_index(first, index);
|
|
};
|
|
|
|
//
|
|
//****************************************************************************
|
|
};// End namespace common
|
|
};// End namespace sort
|
|
};// End namespace boost
|
|
//****************************************************************************
|
|
//
|
|
#endif
|