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+//----------------------------------------------------------------------------
+/// @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 <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