//----------------------------------------------------------------------------
/// @file merge.hpp
/// @brief low level merge functions
///
/// @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_COMMON_UTIL_MERGE_HPP
#define __BOOST_SORT_COMMON_UTIL_MERGE_HPP
#include <ciso646>
#include <algorithm>
#include <functional>
#include <iterator>
#include <memory>
#include <boost/sort/common/util/algorithm.hpp>
#include <boost/sort/common/util/traits.hpp>
#include <boost/sort/common/util/circular_buffer.hpp>
namespace boost
{
namespace sort
{
namespace common
{
namespace util
{
namespace here = boost::sort::common::util;
//----------------------------------------------------------------------------
//
// F U N C T I O N S I N T H E F I L E
//----------------------------------------------------------------------------
//
// template < class Iter1_t, class Iter2_t, class Compare >
// Iter2_t merge (Iter1_t buf1, const Iter1_t end_buf1, Iter1_t buf2,
// const Iter1_t end_buf2, Iter2_t buf_out, Compare comp)
//
// template < class Iter_t, class Value_t, class Compare >
// Value_t *merge_construct (Iter_t first1, const Iter_t last1, Iter_t first2,
// const Iter_t last2, Value_t *it_out, Compare comp)
//
// template < class Iter1_t, class Iter2_t, class Compare >
// Iter2_t merge_half (Iter1_t buf1, const Iter1_t end_buf1, Iter2_t buf2,
// const Iter2_t end_buf2, Iter2_t buf_out, Compare comp)
//
// template < class Iter1_t, class Iter2_t, class Compare >
// Iter2_t merge_half_backward (Iter1_t buf1, Iter1_t end_buf1,
// Iter2_t buf2, Iter2_t end_buf2,
// Iter1_t end_buf_out, Compare comp)
//
// template < class Iter1_t, class Iter2_t, class Iter3_t, class Compare >
// bool merge_uncontiguous (Iter1_t src1, const Iter1_t end_src1,
// Iter2_t src2, const Iter2_t end_src2,
// Iter3_t aux, Compare comp)
//
// template < class Iter1_t, class Iter2_t, class Compare >
// bool merge_contiguous (Iter1_t src1, Iter1_t src2, Iter1_t end_src2,
// Iter2_t buf, Compare comp)
//
// template < class Iter_t, class Circular ,class Compare >
// bool merge_circular (Iter_t buf1, Iter_t end_buf1,
// Iter_t buf2, Iter_t end_buf2,
// Circular &circ, Compare comp, Iter_t &it_aux)
//
//----------------------------------------------------------------------------
//
//-----------------------------------------------------------------------------
// function : merge
/// @brief Merge two contiguous buffers pointed by buf1 and buf2, and put
/// in the buffer pointed by buf_out
///
/// @param buf1 : iterator to the first element in the first buffer
/// @param end_buf1 : final iterator of first buffer
/// @param buf2 : iterator to the first iterator to the second buffer
/// @param end_buf2 : final iterator of the second buffer
/// @param buf_out : buffer where move the elements merged
/// @param comp : comparison object
//-----------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Iter3_t, class Compare>
static Iter3_t merge(Iter1_t buf1, const Iter1_t end_buf1, Iter2_t buf2,
const Iter2_t end_buf2, Iter3_t buf_out, Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> value1_t;
typedef value_iter<Iter2_t> value2_t;
typedef value_iter<Iter3_t> value3_t;
static_assert (std::is_same< value1_t, value2_t >::value,
"Incompatible iterators\n");
static_assert (std::is_same< value3_t, value2_t >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
const size_t MIN_CHECK = 1024;
if (size_t((end_buf1 - buf1) + (end_buf2 - buf2)) >= MIN_CHECK)
{
if (buf1 == end_buf1) return move_forward(buf_out, buf2, end_buf2);
if (buf2 == end_buf2) return move_forward(buf_out, buf1, end_buf1);
if (not comp(*buf2, *(end_buf1 - 1)))
{
Iter3_t mid = move_forward(buf_out, buf1, end_buf1);
return move_forward(mid, buf2, end_buf2);
};
if (comp(*(end_buf2 - 1), *buf1))
{
Iter3_t mid = move_forward(buf_out, buf2, end_buf2);
return move_forward(mid, buf1, end_buf1);
};
};
while ((buf1 != end_buf1) and (buf2 != end_buf2))
{
*(buf_out++) = (not comp(*buf2, *buf1)) ?
std::move(*(buf1++)) : std::move(*(buf2++));
};
return (buf1 == end_buf1) ?
move_forward(buf_out, buf2, end_buf2) :
move_forward(buf_out, buf1, end_buf1);
}
;
//
//-----------------------------------------------------------------------------
// function : merge_construct
/// @brief Merge two contiguous buffers pointed by first1 and first2, and put
/// in the uninitialized buffer pointed by it_out
///
/// @param first1 : iterator to the first element in the first buffer
/// @param last1 : last iterator of the first buffer
/// @param first2 : iterator to the first element to the second buffer
/// @param last2 : final iterator of the second buffer
/// @param it_out : uninitialized buffer where move the elements merged
/// @param comp : comparison object
//-----------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Value_t, class Compare>
static Value_t *merge_construct(Iter1_t first1, const Iter1_t last1,
Iter2_t first2, const Iter2_t last2,
Value_t *it_out, Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> type1;
typedef value_iter<Iter2_t> type2;
static_assert (std::is_same< Value_t, type1 >::value,
"Incompatible iterators\n");
static_assert (std::is_same< Value_t, type2 >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
const size_t MIN_CHECK = 1024;
if (size_t((last1 - first1) + (last2 - first2)) >= MIN_CHECK)
{
if (first1 == last1) return move_construct(it_out, first2, last2);
if (first2 == last2) return move_construct(it_out, first1, last1);
if (not comp(*first2, *(last1 - 1)))
{
Value_t* mid = move_construct(it_out, first1, last1);
return move_construct(mid, first2, last2);
};
if (comp(*(last2 - 1), *first1))
{
Value_t* mid = move_construct(it_out, first2, last2);
return move_construct(mid, first1, last1);
};
};
while (first1 != last1 and first2 != last2)
{
construct_object((it_out++),
(not comp(*first2, *first1)) ?
std::move(*(first1++)) :
std::move(*(first2++)));
};
return (first1 == last1) ?
move_construct(it_out, first2, last2) :
move_construct(it_out, first1, last1);
};
//
//---------------------------------------------------------------------------
// function : merge_half
/// @brief : Merge two buffers. The first buffer is in a separate memory.
/// The second buffer have a empty space before buf2 of the same size
/// than the (end_buf1 - buf1)
///
/// @param buf1 : iterator to the first element of the first buffer
/// @param end_buf1 : iterator to the last element of the first buffer
/// @param buf2 : iterator to the first element of the second buffer
/// @param end_buf2 : iterator to the last element of the second buffer
/// @param buf_out : iterator to the first element to the buffer where put
/// the result
/// @param comp : object for Compare two elements of the type pointed
/// by the Iter1_t and Iter2_t
//---------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Compare>
static Iter2_t merge_half(Iter1_t buf1, const Iter1_t end_buf1, Iter2_t buf2,
const Iter2_t end_buf2, Iter2_t buf_out, Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> value1_t;
typedef value_iter<Iter2_t> value2_t;
static_assert (std::is_same< value1_t, value2_t >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
#ifdef __BS_DEBUG
assert ( (buf2 - buf_out) == ( end_buf1 - buf1));
#endif
const size_t MIN_CHECK = 1024;
if (size_t((end_buf1 - buf1) + (end_buf2 - buf2)) >= MIN_CHECK)
{
if (buf1 == end_buf1) return end_buf2;
if (buf2 == end_buf2) return move_forward(buf_out, buf1, end_buf1);
if (not comp(*buf2, *(end_buf1 - 1)))
{
move_forward(buf_out, buf1, end_buf1);
return end_buf2;
};
if (comp(*(end_buf2 - 1), *buf1))
{
Iter2_t mid = move_forward(buf_out, buf2, end_buf2);
return move_forward(mid, buf1, end_buf1);
};
};
while ((buf1 != end_buf1) and (buf2 != end_buf2))
{
*(buf_out++) = (not comp(*buf2, *buf1)) ?
std::move(*(buf1++)) : std::move(*(buf2++));
};
return (buf2 == end_buf2)? move_forward(buf_out, buf1, end_buf1) : end_buf2;
};
//
//---------------------------------------------------------------------------
// function : merge_half_backward
/// @brief : Merge two buffers. The first buffer is in a separate memory.
/// The second buffer have a empty space before buf2 of the same size
/// than the (end_buf1 - buf1)
///
/// @param buf1 : iterator to the first element of the first buffer
/// @param end_buf1 : iterator to the last element of the first buffer
/// @param buf2 : iterator to the first element of the second buffer
/// @param end_buf2 : iterator to the last element of the second buffer
/// @param buf_out : iterator to the first element to the buffer where put
/// the result
/// @param comp : object for Compare two elements of the type pointed
/// by the Iter1_t and Iter2_t
//---------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Compare>
static Iter2_t merge_half_backward(Iter1_t buf1, Iter1_t end_buf1, Iter2_t buf2,
Iter2_t end_buf2, Iter1_t end_buf_out,
Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> value1_t;
typedef value_iter<Iter2_t> value2_t;
static_assert (std::is_same< value1_t, value2_t >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
#ifdef __BS_DEBUG
assert ((end_buf_out - end_buf1) == (end_buf2 - buf2) );
#endif
const size_t MIN_CHECK = 1024;
if (size_t((end_buf1 - buf1) + (end_buf2 - buf2)) >= MIN_CHECK)
{
if (buf2 == end_buf2) return buf1;
if (buf1 == end_buf1)
return here::move_backward(end_buf_out, buf2, end_buf2);
if (not comp(*buf2, *(end_buf1 - 1)))
{
here::move_backward(end_buf_out, buf2, end_buf2);
return buf1;
};
if (comp(*(end_buf2 - 1), *buf1))
{
Iter1_t mid = here::move_backward(end_buf_out, buf1, end_buf1);
return here::move_backward(mid, buf2, end_buf2);
};
};
while ((buf1 != end_buf1) and (buf2 != end_buf2))
{
*(--end_buf_out) =
(not comp(*(end_buf2 - 1), *(end_buf1 - 1))) ?
std::move(*(--end_buf2)):
std::move(*(--end_buf1));
};
return (buf1 == end_buf1) ?
here::move_backward(end_buf_out, buf2, end_buf2) : buf1;
};
//
//-----------------------------------------------------------------------------
// function : merge_uncontiguous
/// @brief : merge two uncontiguous buffers, placing the results in the buffers
/// Use an auxiliary buffer pointed by aux
///
/// @param src1 : iterator to the first element of the first buffer
/// @param end_src1 : last iterator of the first buffer
/// @param src2 : iterator to the first element of the second buffer
/// @param end_src2 : last iterator of the second buffer
/// @param aux : iterator to the first element of the auxiliary buffer
/// @param comp : object for to Compare elements
/// @return true : not changes done, false : changes in the buffers
/// @remarks
//-----------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Iter3_t, class Compare>
static bool merge_uncontiguous(Iter1_t src1, const Iter1_t end_src1,
Iter2_t src2, const Iter2_t end_src2,
Iter3_t aux, Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> type1;
typedef value_iter<Iter2_t> type2;
typedef value_iter<Iter3_t> type3;
static_assert (std::is_same< type1, type2 >::value,
"Incompatible iterators\n");
static_assert (std::is_same< type3, type2 >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
if (src1 == end_src1 or src2 == end_src2
or not comp(*src2, *(end_src1 - 1))) return true;
while (src1 != end_src1 and not comp(*src2, *src1))
++src1;
Iter3_t const end_aux = aux + (end_src1 - src1);
Iter2_t src2_first = src2;
move_forward(aux, src1, end_src1);
while ((src1 != end_src1) and (src2 != end_src2))
{
*(src1++) = std::move((not comp(*src2, *aux)) ? *(aux++) : *(src2++));
}
if (src2 == end_src2)
{
while (src1 != end_src1)
*(src1++) = std::move(*(aux++));
move_forward(src2_first, aux, end_aux);
}
else
{
merge_half(aux, end_aux, src2, end_src2, src2_first, comp);
};
return false;
};
//
//-----------------------------------------------------------------------------
// function : merge_contiguous
/// @brief : merge two contiguous buffers,using an auxiliary buffer pointed
/// by buf. The results are in src1 and src2
///
/// @param src1: iterator to the first position of the first buffer
/// @param src2: final iterator of the first buffer and first iterator
/// of the second buffer
/// @param end_src2 : final iterator of the second buffer
/// @param buf : iterator to buffer used as auxiliary memory
/// @param comp : object for to Compare elements
/// @return true : not changes done, false : changes in the buffers
//-----------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Compare>
static bool merge_contiguous(Iter1_t src1, Iter1_t src2, Iter1_t end_src2,
Iter2_t buf, Compare comp)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> type1;
typedef value_iter<Iter2_t> type2;
static_assert (std::is_same< type1, type2 >::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
if (src1 == src2 or src2 == end_src2 or not comp(*src2, *(src2 - 1)))
return true;
Iter1_t end_src1 = src2;
while (src1 != end_src1 and not comp(*src2, *src1))
++src1;
if (src1 == end_src1) return false;
size_t nx = end_src1 - src1;
move_forward(buf, src1, end_src1);
merge_half(buf, buf + nx, src2, end_src2, src1, comp);
return false;
};
//
//-----------------------------------------------------------------------------
// function : merge_circular
/// @brief : merge two buffers,using a circular buffer
/// This function don't check the parameters
/// @param buf1: iterator to the first position of the first buffer
/// @param end_buf1: iterator after the last element of the first buffer
/// @param buf2: iterator to the first element of the secind buffer
/// @param end_buf2: iterator to the first element of the secind buffer
/// @param circ : circular buffer
/// @param comp : comparison object
/// @return true : finished buf1, false : finished buf2
/// @comments : be carefully because the iterators buf1 and buf2 are modified
//-----------------------------------------------------------------------------
template<class Iter1_t, class Iter2_t, class Circular, class Compare>
static bool merge_circular(Iter1_t buf1, Iter1_t end_buf1, Iter2_t buf2,
Iter2_t end_buf2, Circular &circ, Compare comp,
Iter1_t &it1_out, Iter2_t &it2_out)
{
//-------------------------------------------------------------------------
// Metaprogramming
//-------------------------------------------------------------------------
typedef value_iter<Iter1_t> type1;
typedef value_iter<Iter2_t> type2;
static_assert (std::is_same< type1, type2 >::value,
"Incompatible iterators\n");
typedef typename Circular::value_t type3;
static_assert (std::is_same<type1, type3>::value,
"Incompatible iterators\n");
//-------------------------------------------------------------------------
// Code
//-------------------------------------------------------------------------
#ifdef __BS_DEBUG
assert ( circ.free_size() >= size_t ((end_buf1-buf1) + (end_buf2-buf2)));
#endif
if (not comp(*buf2, *(end_buf1 - 1)))
{
circ.push_move_back(buf1, (end_buf1 - buf1));
it1_out = end_buf1;
it2_out = buf2;
return true;
};
if (comp(*(end_buf2 - 1), *buf1))
{
circ.push_move_back(buf2, (end_buf2 - buf2));
it1_out = buf1;
it2_out = end_buf2;
return false;
}
while (buf1 != end_buf1 and buf2 != end_buf2)
{
circ.push_back(comp(*buf2, *buf1) ? std::move(*(buf2++))
: std::move(*(buf1++)));
};
it2_out = buf2;
it1_out = buf1;
bool ret = (buf1 == end_buf1);
return ret;
};
//
//****************************************************************************
};// End namespace util
};// End namespace common
};// End namespace sort
};// End namespace boost
//****************************************************************************
//
#endif