boost/move/algo/detail/adaptive_sort_merge.hpp
////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2015-2016. // Distributed under the Boost Software License, Version 1.0. // (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) // // See http://www.boost.org/libs/move for documentation. // ////////////////////////////////////////////////////////////////////////////// // // Stable sorting that works in O(N*log(N)) worst time // and uses O(1) extra memory // ////////////////////////////////////////////////////////////////////////////// // // The main idea of the adaptive_sort algorithm was developed by Andrey Astrelin // and explained in the article from the russian collaborative blog // Habrahabr (http://habrahabr.ru/post/205290/). The algorithm is based on // ideas from B-C. Huang and M. A. Langston explained in their article // "Fast Stable Merging and Sorting in Constant Extra Space (1989-1992)" // (http://comjnl.oxfordjournals.org/content/35/6/643.full.pdf). // // This implementation by Ion Gaztanaga uses previous ideas with additional changes: // // - Use of GCD-based rotation. // - Non power of two buffer-sizes. // - Tries to find sqrt(len)*2 unique keys, so that the merge sort // phase can form up to sqrt(len)*4 segments if enough keys are found. // - The merge-sort phase can take advantage of external memory to // save some additional combination steps. // - Combination phase: Blocks are selection sorted and merged in parallel. // - The combination phase is performed alternating merge to left and merge // to right phases minimizing swaps due to internal buffer repositioning. // - When merging blocks special optimizations are made to avoid moving some // elements twice. // // The adaptive_merge algorithm was developed by Ion Gaztanaga reusing some parts // from the sorting algorithm and implementing an additional block merge algorithm // without moving elements to left or right. ////////////////////////////////////////////////////////////////////////////// #ifndef BOOST_MOVE_ADAPTIVE_SORT_MERGE_HPP #define BOOST_MOVE_ADAPTIVE_SORT_MERGE_HPP #include <boost/move/detail/config_begin.hpp> #include <boost/move/detail/reverse_iterator.hpp> #include <boost/move/algo/move.hpp> #include <boost/move/algo/detail/merge.hpp> #include <boost/move/adl_move_swap.hpp> #include <boost/move/algo/detail/insertion_sort.hpp> #include <boost/move/algo/detail/merge_sort.hpp> #include <boost/move/algo/detail/merge.hpp> #include <boost/assert.hpp> #include <boost/cstdint.hpp> #ifdef BOOST_MOVE_ADAPTIVE_SORT_STATS #define BOOST_MOVE_ADAPTIVE_SORT_PRINT(STR, L) \ print_stats(STR, L)\ // #else #define BOOST_MOVE_ADAPTIVE_SORT_PRINT(STR, L) #endif #ifdef BOOST_MOVE_ADAPTIVE_SORT_INVARIANTS #define BOOST_MOVE_ADAPTIVE_SORT_INVARIANT BOOST_ASSERT #else #define BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(L) #endif namespace boost { namespace movelib { namespace detail_adaptive { static const std::size_t AdaptiveSortInsertionSortThreshold = 16; //static const std::size_t AdaptiveSortInsertionSortThreshold = 4; BOOST_STATIC_ASSERT((AdaptiveSortInsertionSortThreshold&(AdaptiveSortInsertionSortThreshold-1)) == 0); #if defined BOOST_HAS_INTPTR_T typedef ::boost::uintptr_t uintptr_t; #else typedef std::size_t uintptr_t; #endif template<class T> const T &min_value(const T &a, const T &b) { return a < b ? a : b; } template<class T> const T &max_value(const T &a, const T &b) { return a > b ? a : b; } template<class ForwardIt, class Pred> bool is_sorted(ForwardIt const first, ForwardIt last, Pred pred) { if (first != last) { ForwardIt next = first, cur(first); while (++next != last) { if (pred(*next, *cur)) return false; cur = next; } } return true; } #if defined(BOOST_MOVE_ADAPTIVE_SORT_INVARIANTS) bool is_sorted(::order_perf_type *first, ::order_perf_type *last, ::order_type_less) { if (first != last) { const order_perf_type *next = first, *cur(first); while (++next != last) { if (!(cur->key < next->key || (cur->key == next->key && cur->val < next->val))) return false; cur = next; } } return true; } #endif //BOOST_MOVE_ADAPTIVE_SORT_INVARIANTS template<class ForwardIt, class Pred> bool is_sorted_and_unique(ForwardIt first, ForwardIt last, Pred pred) { if (first != last) { ForwardIt next = first; while (++next != last) { if (!pred(*first, *next)) return false; first = next; } } return true; } template<class ForwardIt, class Pred, class V> typename iterator_traits<ForwardIt>::size_type count_if_with(ForwardIt first, ForwardIt last, Pred pred, const V &v) { typedef typename iterator_traits<ForwardIt>::size_type size_type; size_type count = 0; while(first != last) { count += static_cast<size_type>(0 != pred(*first, v)); ++first; } return count; } template<class T, class RandRawIt = T*> class adaptive_xbuf { adaptive_xbuf(const adaptive_xbuf &); adaptive_xbuf & operator=(const adaptive_xbuf &); public: typedef RandRawIt iterator; adaptive_xbuf() : m_ptr(), m_size(0), m_capacity(0) {} adaptive_xbuf(RandRawIt raw_memory, std::size_t capacity) : m_ptr(raw_memory), m_size(0), m_capacity(capacity) {} template<class RandIt> void move_assign(RandIt first, std::size_t n) { if(n <= m_size){ boost::move(first, first+n, m_ptr); std::size_t size = m_size; while(size-- != n){ m_ptr[size].~T(); } m_size = n; } else{ RandRawIt result = boost::move(first, first+m_size, m_ptr); boost::uninitialized_move(first+m_size, first+n, result); m_size = n; } } template<class RandIt> void push_back(RandIt first, std::size_t n) { BOOST_ASSERT(m_capacity - m_size >= n); boost::uninitialized_move(first, first+n, m_ptr+m_size); m_size += n; } template<class RandIt> iterator add(RandIt it) { BOOST_ASSERT(m_size < m_capacity); RandRawIt p_ret = m_ptr + m_size; ::new(&*p_ret) T(::boost::move(*it)); ++m_size; return p_ret; } template<class RandIt> void insert(iterator pos, RandIt it) { if(pos == (m_ptr + m_size)){ this->add(it); } else{ this->add(m_ptr+m_size-1); //m_size updated boost::move_backward(pos, m_ptr+m_size-2, m_ptr+m_size-1); *pos = boost::move(*it); } } void set_size(std::size_t size) { m_size = size; } void shrink_to_fit(std::size_t const size) { if(m_size > size){ for(std::size_t szt_i = size; szt_i != m_size; ++szt_i){ m_ptr[szt_i].~T(); } m_size = size; } } void initialize_until(std::size_t const size, T &t) { BOOST_ASSERT(m_size < m_capacity); if(m_size < size){ ::new((void*)&m_ptr[m_size]) T(::boost::move(t)); ++m_size; for(; m_size != size; ++m_size){ ::new((void*)&m_ptr[m_size]) T(::boost::move(m_ptr[m_size-1])); } t = ::boost::move(m_ptr[m_size-1]); } } private: template<class RIt> static bool is_raw_ptr(RIt) { return false; } static bool is_raw_ptr(T*) { return true; } public: template<class U> bool supports_aligned_trailing(std::size_t size, std::size_t trail_count) const { if(this->is_raw_ptr(this->data()) && m_capacity){ uintptr_t u_addr_sz = uintptr_t(&*(this->data()+size)); uintptr_t u_addr_cp = uintptr_t(&*(this->data()+this->capacity())); u_addr_sz = ((u_addr_sz + sizeof(U)-1)/sizeof(U))*sizeof(U); return (u_addr_cp >= u_addr_sz) && ((u_addr_cp - u_addr_sz)/sizeof(U) >= trail_count); } return false; } template<class U> U *aligned_trailing() const { return this->aligned_trailing<U>(this->size()); } template<class U> U *aligned_trailing(std::size_t pos) const { uintptr_t u_addr = uintptr_t(&*(this->data()+pos)); u_addr = ((u_addr + sizeof(U)-1)/sizeof(U))*sizeof(U); return (U*)u_addr; } ~adaptive_xbuf() { this->clear(); } std::size_t capacity() const { return m_capacity; } iterator data() const { return m_ptr; } iterator end() const { return m_ptr+m_size; } std::size_t size() const { return m_size; } bool empty() const { return !m_size; } void clear() { this->shrink_to_fit(0u); } private: RandRawIt m_ptr; std::size_t m_size; std::size_t m_capacity; }; template<class Iterator, class Op> class range_xbuf { range_xbuf(const range_xbuf &); range_xbuf & operator=(const range_xbuf &); public: typedef typename iterator_traits<Iterator>::size_type size_type; typedef Iterator iterator; range_xbuf(Iterator first, Iterator last) : m_first(first), m_last(first), m_cap(last) {} template<class RandIt> void move_assign(RandIt first, std::size_t n) { BOOST_ASSERT(size_type(n) <= size_type(m_cap-m_first)); m_last = Op()(forward_t(), first, first+n, m_first); } ~range_xbuf() {} std::size_t capacity() const { return m_cap-m_first; } Iterator data() const { return m_first; } Iterator end() const { return m_last; } std::size_t size() const { return m_last-m_first; } bool empty() const { return m_first == m_last; } void clear() { m_last = m_first; } template<class RandIt> iterator add(RandIt it) { Iterator pos(m_last); *pos = boost::move(*it); ++m_last; return pos; } void set_size(std::size_t size) { m_last = m_first; m_last += size; } private: Iterator const m_first; Iterator m_last; Iterator const m_cap; }; template<class RandIt, class Compare> RandIt skip_until_merge ( RandIt first1, RandIt const last1 , const typename iterator_traits<RandIt>::value_type &next_key, Compare comp) { while(first1 != last1 && !comp(next_key, *first1)){ ++first1; } return first1; } template<class RandIt1, class RandIt2, class RandItB, class Compare, class Op> RandItB op_buffered_partial_merge_to_range1_and_buffer ( RandIt1 first1, RandIt1 const last1 , RandIt2 &rfirst2, RandIt2 const last2 , RandItB &rfirstb, Compare comp, Op op ) { RandItB firstb = rfirstb; RandItB lastb = firstb; RandIt2 first2 = rfirst2; //Move to buffer while merging //Three way moves need less moves when op is swap_op so use it //when merging elements from range2 to the destination occupied by range1 if(first1 != last1 && first2 != last2){ op(three_way_t(), first2++, first1++, lastb++); while(true){ if(first1 == last1){ break; } if(first2 == last2){ lastb = op(forward_t(), first1, last1, firstb); break; } op(three_way_t(), comp(*first2, *firstb) ? first2++ : firstb++, first1++, lastb++); } rfirst2 = first2; rfirstb = firstb; } return lastb; } template<class RandItKeys, class RandIt> void swap_and_update_key ( bool is_next_far_away , RandItKeys const key_next , RandItKeys const key_range2 , RandItKeys &key_mid , RandIt const begin , RandIt const end , RandIt const with) { if(is_next_far_away){ ::boost::adl_move_swap_ranges(begin, end, with); ::boost::adl_move_swap(*key_next, *key_range2); if(key_next == key_mid){ key_mid = key_range2; } else if(key_mid == key_range2){ key_mid = key_next; } } } /////////////////////////////////////////////////////////////////////////////// // // MERGE BUFFERLESS // /////////////////////////////////////////////////////////////////////////////// // [first1, last1) merge [last1,last2) -> [first1,last2) template<class RandIt, class Compare> RandIt partial_merge_bufferless_impl (RandIt first1, RandIt last1, RandIt const last2, bool *const pis_range1_A, Compare comp) { if(last1 == last2){ return first1; } bool const is_range1_A = *pis_range1_A; if(first1 != last1 && comp(*last1, last1[-1])){ do{ RandIt const old_last1 = last1; last1 = boost::movelib::lower_bound(last1, last2, *first1, comp); first1 = rotate_gcd(first1, old_last1, last1);//old_last1 == last1 supported if(last1 == last2){ return first1; } do{ ++first1; } while(last1 != first1 && !comp(*last1, *first1) ); } while(first1 != last1); } *pis_range1_A = !is_range1_A; return last1; } // [first1, last1) merge [last1,last2) -> [first1,last2) template<class RandIt, class Compare> RandIt partial_merge_bufferless (RandIt first1, RandIt last1, RandIt const last2, bool *const pis_range1_A, Compare comp) { return *pis_range1_A ? partial_merge_bufferless_impl(first1, last1, last2, pis_range1_A, comp) : partial_merge_bufferless_impl(first1, last1, last2, pis_range1_A, antistable<Compare>(comp)); } template<class SizeType> static SizeType needed_keys_count(SizeType n_block_a, SizeType n_block_b) { return n_block_a + n_block_b; } template<class RandItKeys, class KeyCompare, class RandIt, class Compare> typename iterator_traits<RandIt>::size_type find_next_block ( RandItKeys key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const ix_first_block , typename iterator_traits<RandIt>::size_type const ix_last_block , Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; typedef typename iterator_traits<RandIt>::value_type value_type; typedef typename iterator_traits<RandItKeys>::value_type key_type; BOOST_ASSERT(ix_first_block <= ix_last_block); size_type ix_min_block = 0u; for (size_type szt_i = ix_first_block; szt_i < ix_last_block; ++szt_i) { const value_type &min_val = first[ix_min_block*l_block]; const value_type &cur_val = first[szt_i*l_block]; const key_type &min_key = key_first[ix_min_block]; const key_type &cur_key = key_first[szt_i]; bool const less_than_minimum = comp(cur_val, min_val) || (!comp(min_val, cur_val) && key_comp(cur_key, min_key)); if (less_than_minimum) { ix_min_block = szt_i; } } return ix_min_block; } template<class RandItKeys, class KeyCompare, class RandIt, class Compare> void merge_blocks_bufferless ( RandItKeys key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const l_irreg1 , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const key_count = needed_keys_count(n_block_a, n_block_b); (void)key_count; //BOOST_ASSERT(n_block_a || n_block_b); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted_and_unique(key_first, key_first + key_count, key_comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_b || n_block_a == count_if_with(key_first, key_first + key_count, key_comp, key_first[n_block_a])); size_type n_bef_irreg2 = 0; bool l_irreg_pos_count = true; RandItKeys key_mid(key_first + n_block_a); RandIt const first_irr2 = first + l_irreg1 + (n_block_a+n_block_b)*l_block; RandIt const last_irr2 = first_irr2 + l_irreg2; { //Selection sort blocks size_type n_block_left = n_block_b + n_block_a; RandItKeys key_range2(key_first); size_type min_check = n_block_a == n_block_left ? 0u : n_block_a; size_type max_check = min_value(min_check+1, n_block_left); for (RandIt f = first+l_irreg1; n_block_left; --n_block_left, ++key_range2, f += l_block, min_check -= min_check != 0, max_check -= max_check != 0) { size_type const next_key_idx = find_next_block(key_range2, key_comp, f, l_block, min_check, max_check, comp); RandItKeys const key_next(key_range2 + next_key_idx); max_check = min_value(max_value(max_check, next_key_idx+2), n_block_left); RandIt const first_min = f + next_key_idx*l_block; //Check if irregular b block should go here. //If so, break to the special code handling the irregular block if (l_irreg_pos_count && l_irreg2 && comp(*first_irr2, *first_min)){ l_irreg_pos_count = false; } n_bef_irreg2 += l_irreg_pos_count; swap_and_update_key(next_key_idx != 0, key_next, key_range2, key_mid, f, f + l_block, first_min); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(f, f+l_block, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first_min, first_min + l_block, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT((f == (first+l_irreg1)) || !comp(*f, *(f-l_block))); } } BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first+l_irreg1+n_bef_irreg2*l_block, first_irr2, comp)); RandIt first1 = first; RandIt last1 = first+l_irreg1; RandItKeys const key_end (key_first+n_bef_irreg2); bool is_range1_A = true; for( ; key_first != key_end; ++key_first){ bool is_range2_A = key_mid == (key_first+key_count) || key_comp(*key_first, *key_mid); first1 = is_range1_A == is_range2_A ? last1 : partial_merge_bufferless(first1, last1, last1 + l_block, &is_range1_A, comp); last1 += l_block; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, first1, comp)); } merge_bufferless(is_range1_A ? first1 : last1, first_irr2, last_irr2, comp); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, last_irr2, comp)); } /////////////////////////////////////////////////////////////////////////////// // // BUFFERED MERGE // /////////////////////////////////////////////////////////////////////////////// template<class RandIt, class Compare, class Op, class Buf> void op_buffered_merge ( RandIt first, RandIt const middle, RandIt last , Compare comp, Op op , Buf &xbuf) { if(first != middle && middle != last && comp(*middle, middle[-1])){ typedef typename iterator_traits<RandIt>::size_type size_type; size_type const len1 = size_type(middle-first); size_type const len2 = size_type(last-middle); if(len1 <= len2){ first = boost::movelib::upper_bound(first, middle, *middle, comp); xbuf.move_assign(first, size_type(middle-first)); op_merge_with_right_placed (xbuf.data(), xbuf.end(), first, middle, last, comp, op); } else{ last = boost::movelib::lower_bound(middle, last, middle[-1], comp); xbuf.move_assign(middle, size_type(last-middle)); op_merge_with_left_placed (first, middle, last, xbuf.data(), xbuf.end(), comp, op); } } } template<class RandIt, class Compare, class XBuf> void buffered_merge ( RandIt first, RandIt const middle, RandIt last , Compare comp , XBuf &xbuf) { op_buffered_merge(first, middle, last, comp, move_op(), xbuf); } // Complexity: 2*distance(first, last)+max_collected^2/2 // // Tries to collect at most n_keys unique elements from [first, last), // in the begining of the range, and ordered according to comp // // Returns the number of collected keys template<class RandIt, class Compare, class XBuf> typename iterator_traits<RandIt>::size_type collect_unique ( RandIt const first, RandIt const last , typename iterator_traits<RandIt>::size_type const max_collected, Compare comp , XBuf & xbuf) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type h = 0; if(max_collected){ ++h; // first key is always here RandIt h0 = first; RandIt u = first; ++u; RandIt search_end = u; if(xbuf.capacity() >= max_collected){ typename XBuf::iterator const ph0 = xbuf.add(first); while(u != last && h < max_collected){ typename XBuf::iterator const r = boost::movelib::lower_bound(ph0, xbuf.end(), *u, comp); //If key not found add it to [h, h+h0) if(r == xbuf.end() || comp(*u, *r) ){ RandIt const new_h0 = boost::move(search_end, u, h0); search_end = u; ++search_end; ++h; xbuf.insert(r, u); h0 = new_h0; } ++u; } boost::move_backward(first, h0, h0+h); boost::move(xbuf.data(), xbuf.end(), first); } else{ while(u != last && h < max_collected){ RandIt const r = boost::movelib::lower_bound(h0, search_end, *u, comp); //If key not found add it to [h, h+h0) if(r == search_end || comp(*u, *r) ){ RandIt const new_h0 = rotate_gcd(h0, search_end, u); search_end = u; ++search_end; ++h; rotate_gcd(r+(new_h0-h0), u, search_end); h0 = new_h0; } ++u; } rotate_gcd(first, h0, h0+h); } } return h; } template<class Unsigned> Unsigned floor_sqrt(Unsigned const n) { Unsigned x = n; Unsigned y = x/2 + (x&1); while (y < x){ x = y; y = (x + n / x)/2; } return x; } template<class Unsigned> Unsigned ceil_sqrt(Unsigned const n) { Unsigned r = floor_sqrt(n); return r + Unsigned((n%r) != 0); } template<class Unsigned> Unsigned floor_merge_multiple(Unsigned const n, Unsigned &base, Unsigned &pow) { Unsigned s = n; Unsigned p = 0; while(s > AdaptiveSortInsertionSortThreshold){ s /= 2; ++p; } base = s; pow = p; return s << p; } template<class Unsigned> Unsigned ceil_merge_multiple(Unsigned const n, Unsigned &base, Unsigned &pow) { Unsigned fm = floor_merge_multiple(n, base, pow); if(fm != n){ if(base < AdaptiveSortInsertionSortThreshold){ ++base; } else{ base = AdaptiveSortInsertionSortThreshold/2 + 1; ++pow; } } return base << pow; } template<class Unsigned> Unsigned ceil_sqrt_multiple(Unsigned const n, Unsigned *pbase = 0) { Unsigned const r = ceil_sqrt(n); Unsigned pow = 0; Unsigned base = 0; Unsigned const res = ceil_merge_multiple(r, base, pow); if(pbase) *pbase = base; return res; } struct less { template<class T> bool operator()(const T &l, const T &r) { return l < r; } }; /////////////////////////////////////////////////////////////////////////////// // // MERGE BLOCKS // /////////////////////////////////////////////////////////////////////////////// //#define ADAPTIVE_SORT_MERGE_SLOW_STABLE_SORT_IS_NLOGN #if defined ADAPTIVE_SORT_MERGE_SLOW_STABLE_SORT_IS_NLOGN template<class RandIt, class Compare> void slow_stable_sort ( RandIt const first, RandIt const last, Compare comp) { boost::movelib::inplace_stable_sort(first, last, comp); } #else //ADAPTIVE_SORT_MERGE_SLOW_STABLE_SORT_IS_NLOGN template<class RandIt, class Compare> void slow_stable_sort ( RandIt const first, RandIt const last, Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type L = size_type(last - first); { //Use insertion sort to merge first elements size_type m = 0; while((L - m) > size_type(AdaptiveSortInsertionSortThreshold)){ insertion_sort(first+m, first+m+size_type(AdaptiveSortInsertionSortThreshold), comp); m += AdaptiveSortInsertionSortThreshold; } insertion_sort(first+m, last, comp); } size_type h = AdaptiveSortInsertionSortThreshold; for(bool do_merge = L > h; do_merge; h*=2){ do_merge = (L - h) > h; size_type p0 = 0; if(do_merge){ size_type const h_2 = 2*h; while((L-p0) > h_2){ merge_bufferless(first+p0, first+p0+h, first+p0+h_2, comp); p0 += h_2; } } if((L-p0) > h){ merge_bufferless(first+p0, first+p0+h, last, comp); } } } #endif //ADAPTIVE_SORT_MERGE_SLOW_STABLE_SORT_IS_NLOGN //Returns new l_block and updates use_buf template<class Unsigned> Unsigned lblock_for_combine (Unsigned const l_block, Unsigned const n_keys, Unsigned const l_data, bool &use_buf) { BOOST_ASSERT(l_data > 1); //We need to guarantee lblock >= l_merged/(n_keys/2) keys for the combination. //We have at least 4 keys guaranteed (which are the minimum to merge 2 ranges) //If l_block != 0, then n_keys is already enough to merge all blocks in all //phases as we've found all needed keys for that buffer and length before. //If l_block == 0 then see if half keys can be used as buffer and the rest //as keys guaranteeing that n_keys >= (2*l_merged)/lblock = if(!l_block){ //If l_block == 0 then n_keys is power of two //(guaranteed by build_params(...)) BOOST_ASSERT(n_keys >= 4); //BOOST_ASSERT(0 == (n_keys &(n_keys-1))); //See if half keys are at least 4 and if half keys fulfill Unsigned const new_buf = n_keys/2; Unsigned const new_keys = n_keys-new_buf; use_buf = new_keys >= 4 && new_keys >= l_data/new_buf; if(use_buf){ return new_buf; } else{ return l_data/n_keys; } } else{ use_buf = true; return l_block; } } template<class RandIt, class Compare, class XBuf> void stable_sort( RandIt first, RandIt last, Compare comp, XBuf & xbuf) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const len = size_type(last - first); size_type const half_len = len/2 + (len&1); if(std::size_t(xbuf.capacity() - xbuf.size()) >= half_len) { merge_sort(first, last, comp, xbuf.data()+xbuf.size()); } else{ slow_stable_sort(first, last, comp); } } template<class RandIt, class Comp, class XBuf> void initialize_keys( RandIt first, RandIt last , Comp comp , XBuf & xbuf) { stable_sort(first, last, comp, xbuf); } template<class RandIt, class U> void initialize_keys( RandIt first, RandIt last , less , U &) { typedef typename iterator_traits<RandIt>::value_type value_type; std::size_t count = std::size_t(last - first); for(std::size_t i = 0; i != count; ++i){ *first = value_type(i); ++first; } } template<class RandIt> void move_data_backward( RandIt cur_pos , typename iterator_traits<RandIt>::size_type const l_data , RandIt new_pos , bool const xbuf_used) { //Move buffer to the total combination right if(xbuf_used){ boost::move_backward(cur_pos, cur_pos+l_data, new_pos+l_data); } else{ boost::adl_move_swap_ranges_backward(cur_pos, cur_pos+l_data, new_pos+l_data); //Rotate does less moves but it seems slower due to cache issues //rotate_gcd(first-l_block, first+len-l_block, first+len); } } template<class RandIt> void move_data_forward( RandIt cur_pos , typename iterator_traits<RandIt>::size_type const l_data , RandIt new_pos , bool const xbuf_used) { //Move buffer to the total combination right if(xbuf_used){ boost::move(cur_pos, cur_pos+l_data, new_pos); } else{ boost::adl_move_swap_ranges(cur_pos, cur_pos+l_data, new_pos); //Rotate does less moves but it seems slower due to cache issues //rotate_gcd(first-l_block, first+len-l_block, first+len); } } template <class Unsigned> Unsigned calculate_total_combined(Unsigned const len, Unsigned const l_prev_merged, Unsigned *pl_irreg_combined = 0) { typedef Unsigned size_type; size_type const l_combined = 2*l_prev_merged; size_type l_irreg_combined = len%l_combined; size_type l_total_combined = len; if(l_irreg_combined <= l_prev_merged){ l_total_combined -= l_irreg_combined; l_irreg_combined = 0; } if(pl_irreg_combined) *pl_irreg_combined = l_irreg_combined; return l_total_combined; } template<class RandItKeys, class KeyCompare, class SizeType, class XBuf> void combine_params ( RandItKeys const keys , KeyCompare key_comp , SizeType l_combined , SizeType const l_prev_merged , SizeType const l_block , XBuf & xbuf //Output , SizeType &n_block_a , SizeType &n_block_b , SizeType &l_irreg1 , SizeType &l_irreg2 //Options , bool do_initialize_keys = true) { typedef SizeType size_type; //Initial parameters for selection sort blocks l_irreg1 = l_prev_merged%l_block; l_irreg2 = (l_combined-l_irreg1)%l_block; BOOST_ASSERT(((l_combined-l_irreg1-l_irreg2)%l_block) == 0); size_type const n_reg_block = (l_combined-l_irreg1-l_irreg2)/l_block; n_block_a = l_prev_merged/l_block; n_block_b = n_reg_block - n_block_a; BOOST_ASSERT(n_reg_block>=n_block_a); //Key initialization if (do_initialize_keys) { initialize_keys(keys, keys + needed_keys_count(n_block_a, n_block_b), key_comp, xbuf); } } template<class RandIt1, class RandIt2, class RandItB, class Compare, class Op> RandItB op_buffered_partial_merge_and_swap_to_range1_and_buffer ( RandIt1 first1, RandIt1 const last1 , RandIt2 &rfirst2, RandIt2 const last2, RandIt2 &rfirst_min , RandItB &rfirstb, Compare comp, Op op ) { RandItB firstb = rfirstb; RandItB lastb = firstb; RandIt2 first2 = rfirst2; //Move to buffer while merging //Three way moves need less moves when op is swap_op so use it //when merging elements from range2 to the destination occupied by range1 if(first1 != last1 && first2 != last2){ RandIt2 first_min = rfirst_min; op(four_way_t(), first2++, first_min++, first1++, lastb++); while(first1 != last1){ if(first2 == last2){ lastb = op(forward_t(), first1, last1, firstb); break; } bool const min_less = comp(*first_min, *firstb); if(min_less){ op( four_way_t(), first2++, first_min++, first1++, lastb++); } else{ op(three_way_t(), firstb++, first1++, lastb++); } } rfirst2 = first2; rfirstb = firstb; rfirst_min = first_min; } return lastb; } ////////////////////////////////// // // partial_merge // ////////////////////////////////// template<class InputIt1, class InputIt2, class OutputIt, class Compare, class Op> OutputIt op_partial_merge_impl (InputIt1 &r_first1, InputIt1 const last1, InputIt2 &r_first2, InputIt2 const last2, OutputIt d_first, Compare comp, Op op) { InputIt1 first1(r_first1); InputIt2 first2(r_first2); if(first2 != last2 && last1 != first1) while(1){ if(comp(*first2, *first1)) { op(first2++, d_first++); if(first2 == last2){ break; } } else{ op(first1++, d_first++); if(first1 == last1){ break; } } } r_first1 = first1; r_first2 = first2; return d_first; } template<class InputIt1, class InputIt2, class OutputIt, class Compare, class Op> OutputIt op_partial_merge (InputIt1 &r_first1, InputIt1 const last1, InputIt2 &r_first2, InputIt2 const last2, OutputIt d_first, Compare comp, Op op, bool is_stable) { return is_stable ? op_partial_merge_impl(r_first1, last1, r_first2, last2, d_first, comp, op) : op_partial_merge_impl(r_first1, last1, r_first2, last2, d_first, antistable<Compare>(comp), op); } ////////////////////////////////// // // partial_merge_and_swap // ////////////////////////////////// template<class InputIt1, class InputIt2, class OutputIt, class Compare, class Op> OutputIt op_partial_merge_and_swap_impl (InputIt1 &r_first1, InputIt1 const last1, InputIt2 &r_first2, InputIt2 const last2, InputIt2 &r_first_min, OutputIt d_first, Compare comp, Op op) { InputIt1 first1(r_first1); InputIt2 first2(r_first2); if(first2 != last2 && last1 != first1) { InputIt2 first_min(r_first_min); bool non_empty_ranges = true; do{ if(comp(*first_min, *first1)) { op(three_way_t(), first2++, first_min++, d_first++); non_empty_ranges = first2 != last2; } else{ op(first1++, d_first++); non_empty_ranges = first1 != last1; } } while(non_empty_ranges); r_first_min = first_min; r_first1 = first1; r_first2 = first2; } return d_first; } template<class RandIt, class InputIt2, class OutputIt, class Compare, class Op> RandIt op_partial_merge_and_swap (RandIt &r_first1, RandIt const last1, RandIt &r_first2, RandIt const last2, InputIt2 &r_first_min, OutputIt d_first, Compare comp, Op op, bool is_stable) { return is_stable ? op_partial_merge_and_swap_impl(r_first1, last1, r_first2, last2, r_first_min, d_first, comp, op) : op_partial_merge_and_swap_impl(r_first1, last1, r_first2, last2, r_first_min, d_first, antistable<Compare>(comp), op); } template<class RandIt, class RandItBuf, class Compare, class Op> RandIt op_partial_merge_and_save_impl ( RandIt first1, RandIt const last1, RandIt &rfirst2, RandIt last2, RandIt first_min , RandItBuf &buf_first1_in_out, RandItBuf &buf_last1_in_out , Compare comp, Op op ) { RandItBuf buf_first1 = buf_first1_in_out; RandItBuf buf_last1 = buf_last1_in_out; RandIt first2(rfirst2); bool const do_swap = first2 != first_min; if(buf_first1 == buf_last1){ //Skip any element that does not need to be moved RandIt new_first1 = skip_until_merge(first1, last1, *first_min, comp); buf_first1 += (new_first1-first1); first1 = new_first1; buf_last1 = do_swap ? op_buffered_partial_merge_and_swap_to_range1_and_buffer(first1, last1, first2, last2, first_min, buf_first1, comp, op) : op_buffered_partial_merge_to_range1_and_buffer (first1, last1, first2, last2, buf_first1, comp, op); first1 = last1; } else{ BOOST_ASSERT((last1-first1) == (buf_last1 - buf_first1)); } //Now merge from buffer first1 = do_swap ? op_partial_merge_and_swap_impl(buf_first1, buf_last1, first2, last2, first_min, first1, comp, op) : op_partial_merge_impl (buf_first1, buf_last1, first2, last2, first1, comp, op); buf_first1_in_out = buf_first1; buf_last1_in_out = buf_last1; rfirst2 = first2; return first1; } template<class RandIt, class RandItBuf, class Compare, class Op> RandIt op_partial_merge_and_save ( RandIt first1, RandIt const last1, RandIt &rfirst2, RandIt last2, RandIt first_min , RandItBuf &buf_first1_in_out , RandItBuf &buf_last1_in_out , Compare comp , Op op , bool is_stable) { return is_stable ? op_partial_merge_and_save_impl (first1, last1, rfirst2, last2, first_min, buf_first1_in_out, buf_last1_in_out, comp, op) : op_partial_merge_and_save_impl (first1, last1, rfirst2, last2, first_min, buf_first1_in_out, buf_last1_in_out, antistable<Compare>(comp), op) ; } template<class RandItKeys, class KeyCompare, class RandIt, class RandIt2, class OutputIt, class Compare, class Op> OutputIt op_merge_blocks_with_irreg ( RandItKeys key_first , RandItKeys key_mid , KeyCompare key_comp , RandIt first_reg , RandIt2 &first_irr , RandIt2 const last_irr , OutputIt dest , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type n_block_left , typename iterator_traits<RandIt>::size_type min_check , typename iterator_traits<RandIt>::size_type max_check , Compare comp, bool const is_stable, Op op) { typedef typename iterator_traits<RandIt>::size_type size_type; for(; n_block_left; --n_block_left, ++key_first, min_check -= min_check != 0, max_check -= max_check != 0){ size_type next_key_idx = find_next_block(key_first, key_comp, first_reg, l_block, min_check, max_check, comp); max_check = min_value(max_value(max_check, next_key_idx+2), n_block_left); RandIt const last_reg = first_reg + l_block; RandIt first_min = first_reg + next_key_idx*l_block; RandIt const last_min = first_min + l_block; (void)last_min; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first_reg, last_reg, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!next_key_idx || is_sorted(first_min, last_min, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT((!next_key_idx || !comp(*first_reg, *first_min ))); OutputIt orig_dest = dest; (void)orig_dest; dest = next_key_idx ? op_partial_merge_and_swap(first_irr, last_irr, first_reg, last_reg, first_min, dest, comp, op, is_stable) : op_partial_merge (first_irr, last_irr, first_reg, last_reg, dest, comp, op, is_stable); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(orig_dest, dest, comp)); if(first_reg == dest){ dest = next_key_idx ? ::boost::adl_move_swap_ranges(first_min, last_min, first_reg) : last_reg; } else{ dest = next_key_idx ? op(three_way_forward_t(), first_reg, last_reg, first_min, dest) : op(forward_t(), first_reg, last_reg, dest); } RandItKeys const key_next(key_first + next_key_idx); swap_and_update_key(next_key_idx != 0, key_next, key_first, key_mid, last_reg, last_reg, first_min); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(orig_dest, dest, comp)); first_reg = last_reg; } return dest; } template<class RandItKeys, class KeyCompare, class RandIt, class Compare, class Op> void op_merge_blocks_left ( RandItKeys const key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const l_irreg1 , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp, Op op) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const key_count = needed_keys_count(n_block_a, n_block_b); (void)key_count; // BOOST_ASSERT(n_block_a || n_block_b); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted_and_unique(key_first, key_first + key_count, key_comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_b || n_block_a == count_if_with(key_first, key_first + key_count, key_comp, key_first[n_block_a])); size_type n_block_b_left = n_block_b; size_type n_block_a_left = n_block_a; size_type n_block_left = n_block_b + n_block_a; RandItKeys key_mid(key_first + n_block_a); RandIt buffer = first - l_block; RandIt first1 = first; RandIt last1 = first1 + l_irreg1; RandIt first2 = last1; RandIt const irreg2 = first2 + n_block_left*l_block; bool is_range1_A = true; RandItKeys key_range2(key_first); //////////////////////////////////////////////////////////////////////////// //Process all regular blocks before the irregular B block //////////////////////////////////////////////////////////////////////////// size_type min_check = n_block_a == n_block_left ? 0u : n_block_a; size_type max_check = min_value(min_check+1, n_block_left); for (; n_block_left; --n_block_left, ++key_range2, min_check -= min_check != 0, max_check -= max_check != 0) { size_type const next_key_idx = find_next_block(key_range2, key_comp, first2, l_block, min_check, max_check, comp); max_check = min_value(max_value(max_check, next_key_idx+2), n_block_left); RandIt const first_min = first2 + next_key_idx*l_block; RandIt const last_min = first_min + l_block; (void)last_min; RandIt const last2 = first2 + l_block; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first1, last1, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first2, last2, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_left || is_sorted(first_min, last_min, comp)); //Check if irregular b block should go here. //If so, break to the special code handling the irregular block if (!n_block_b_left && ( (l_irreg2 && comp(*irreg2, *first_min)) || (!l_irreg2 && is_range1_A)) ){ break; } RandItKeys const key_next(key_range2 + next_key_idx); bool const is_range2_A = key_mid == (key_first+key_count) || key_comp(*key_next, *key_mid); bool const is_buffer_middle = last1 == buffer; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT( ( is_buffer_middle && size_type(first2-buffer) == l_block && buffer == last1) || (!is_buffer_middle && size_type(first1-buffer) == l_block && first2 == last1)); if(is_range1_A == is_range2_A){ BOOST_ASSERT((first1 == last1) || !comp(*first_min, last1[-1])); if(!is_buffer_middle){ buffer = op(forward_t(), first1, last1, buffer); } swap_and_update_key(next_key_idx != 0, key_next, key_range2, key_mid, first2, last2, first_min); first1 = first2; last1 = last2; } else { RandIt unmerged; RandIt buf_beg; RandIt buf_end; if(is_buffer_middle){ buf_end = buf_beg = first2 - (last1-first1); unmerged = op_partial_merge_and_save( first1, last1, first2, last2, first_min , buf_beg, buf_end, comp, op, is_range1_A); } else{ buf_beg = first1; buf_end = last1; unmerged = op_partial_merge_and_save (buffer, buffer+(last1-first1), first2, last2, first_min, buf_beg, buf_end, comp, op, is_range1_A); } (void)unmerged; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first-l_block, unmerged, comp)); swap_and_update_key( next_key_idx != 0, key_next, key_range2, key_mid, first2, last2 , last_min - size_type(last2 - first2)); if(buf_beg != buf_end){ //range2 exhausted: is_buffer_middle for the next iteration first1 = buf_beg; last1 = buf_end; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(buf_end == (last2-l_block)); buffer = last1; } else{ //range1 exhausted: !is_buffer_middle for the next iteration first1 = first2; last1 = last2; buffer = first2 - l_block; is_range1_A = is_range2_A; } } BOOST_MOVE_ADAPTIVE_SORT_INVARIANT( (is_range2_A && n_block_a_left) || (!is_range2_A && n_block_b_left)); is_range2_A ? --n_block_a_left : --n_block_b_left; first2 = last2; } BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_b || n_block_a == count_if_with(key_first, key_range2 + n_block_left, key_comp, *key_mid)); BOOST_ASSERT(!n_block_b_left); //////////////////////////////////////////////////////////////////////////// //Process remaining range 1 left before the irregular B block //////////////////////////////////////////////////////////////////////////// bool const is_buffer_middle = last1 == buffer; RandIt first_irr2 = irreg2; RandIt const last_irr2 = first_irr2 + l_irreg2; if(l_irreg2 && is_range1_A){ if(is_buffer_middle){ first1 = skip_until_merge(first1, last1, *first_irr2, comp); //Even if we copy backward, no overlapping occurs so use forward copy //that can be faster specially with trivial types RandIt const new_first1 = first2 - (last1 - first1); op(forward_t(), first1, last1, new_first1); first1 = new_first1; last1 = first2; buffer = first1 - l_block; } buffer = op_partial_merge_impl(first1, last1, first_irr2, last_irr2, buffer, comp, op); buffer = op(forward_t(), first1, last1, buffer); } else if(!is_buffer_middle){ buffer = op(forward_t(), first1, last1, buffer); } BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first-l_block, buffer, comp)); //////////////////////////////////////////////////////////////////////////// //Process irregular B block and remaining A blocks //////////////////////////////////////////////////////////////////////////// buffer = op_merge_blocks_with_irreg ( key_range2, key_mid, key_comp, first2, first_irr2, last_irr2 , buffer, l_block, n_block_left, min_check, max_check, comp, false, op); buffer = op(forward_t(), first_irr2, last_irr2, buffer);(void)buffer; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first-l_block, buffer, comp)); } // first - first element to merge. // first[-l_block, 0) - buffer (if use_buf == true) // l_block - length of regular blocks. First nblocks are stable sorted by 1st elements and key-coded // keys - sequence of keys, in same order as blocks. key<midkey means stream A // n_bef_irreg2/n_aft_irreg2 are regular blocks // l_irreg2 is a irregular block, that is to be combined after n_bef_irreg2 blocks and before n_aft_irreg2 blocks // If l_irreg2==0 then n_aft_irreg2==0 (no irregular blocks). template<class RandItKeys, class KeyCompare, class RandIt, class Compare> void merge_blocks_left ( RandItKeys const key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const l_irreg1 , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp , bool const xbuf_used) { BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_b || n_block_a == count_if_with(key_first, key_first + needed_keys_count(n_block_a, n_block_b), key_comp, key_first[n_block_a])); if(xbuf_used){ op_merge_blocks_left (key_first, key_comp, first, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, move_op()); } else{ op_merge_blocks_left (key_first, key_comp, first, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, swap_op()); } } // first - first element to merge. // [first+l_block*(n_bef_irreg2+n_aft_irreg2)+l_irreg2, first+l_block*(n_bef_irreg2+n_aft_irreg2+1)+l_irreg2) - buffer // l_block - length of regular blocks. First nblocks are stable sorted by 1st elements and key-coded // keys - sequence of keys, in same order as blocks. key<midkey means stream A // n_bef_irreg2/n_aft_irreg2 are regular blocks // l_irreg2 is a irregular block, that is to be combined after n_bef_irreg2 blocks and before n_aft_irreg2 blocks // If l_irreg2==0 then n_aft_irreg2==0 (no irregular blocks). template<class RandItKeys, class KeyCompare, class RandIt, class Compare> void merge_blocks_right ( RandItKeys const key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp , bool const xbuf_used) { merge_blocks_left ( make_reverse_iterator(key_first + needed_keys_count(n_block_a, n_block_b)) , inverse<KeyCompare>(key_comp) , make_reverse_iterator(first + ((n_block_a+n_block_b)*l_block+l_irreg2)) , l_block , l_irreg2 , n_block_b , n_block_a , 0 , inverse<Compare>(comp), xbuf_used); } template<class RandItKeys, class KeyCompare, class RandIt, class Compare, class Op, class RandItBuf> void op_merge_blocks_with_buf ( RandItKeys key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const l_irreg1 , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp , Op op , RandItBuf const buf_first) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const key_count = needed_keys_count(n_block_a, n_block_b); (void)key_count; //BOOST_ASSERT(n_block_a || n_block_b); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted_and_unique(key_first, key_first + key_count, key_comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_b || n_block_a == count_if_with(key_first, key_first + key_count, key_comp, key_first[n_block_a])); size_type n_block_b_left = n_block_b; size_type n_block_a_left = n_block_a; size_type n_block_left = n_block_b + n_block_a; RandItKeys key_mid(key_first + n_block_a); RandItBuf buffer = buf_first; RandItBuf buffer_end = buffer; RandIt first1 = first; RandIt last1 = first1 + l_irreg1; RandIt first2 = last1; RandIt const first_irr2 = first2 + n_block_left*l_block; bool is_range1_A = true; RandItKeys key_range2(key_first); //////////////////////////////////////////////////////////////////////////// //Process all regular blocks before the irregular B block //////////////////////////////////////////////////////////////////////////// size_type min_check = n_block_a == n_block_left ? 0u : n_block_a; size_type max_check = min_value(min_check+1, n_block_left); for (; n_block_left; --n_block_left, ++key_range2, min_check -= min_check != 0, max_check -= max_check != 0) { size_type const next_key_idx = find_next_block(key_range2, key_comp, first2, l_block, min_check, max_check, comp); max_check = min_value(max_value(max_check, next_key_idx+2), n_block_left); RandIt first_min = first2 + next_key_idx*l_block; RandIt const last_min = first_min + l_block; (void)last_min; RandIt const last2 = first2 + l_block; bool const buffer_empty = buffer == buffer_end; (void)buffer_empty; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(buffer_empty ? is_sorted(first1, last1, comp) : is_sorted(buffer, buffer_end, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first2, last2, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!n_block_left || is_sorted(first_min, last_min, comp)); //Check if irregular b block should go here. //If so, break to the special code handling the irregular block if (!n_block_b_left && ( (l_irreg2 && comp(*first_irr2, *first_min)) || (!l_irreg2 && is_range1_A)) ){ break; } RandItKeys const key_next(key_range2 + next_key_idx); bool const is_range2_A = key_mid == (key_first+key_count) || key_comp(*key_next, *key_mid); if(is_range1_A == is_range2_A){ BOOST_MOVE_ADAPTIVE_SORT_INVARIANT((first1 == last1) || (buffer_empty ? !comp(*first_min, last1[-1]) : !comp(*first_min, buffer_end[-1]))); //If buffered, put those elements in place RandIt res = op(forward_t(), buffer, buffer_end, first1); buffer = buffer_end = buf_first; BOOST_ASSERT(buffer_empty || res == last1); (void)res; swap_and_update_key(next_key_idx != 0, key_next, key_range2, key_mid, first2, last2, first_min); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first2, last2, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first_min, last_min, comp)); first1 = first2; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, first1, comp)); } else { RandIt const unmerged = op_partial_merge_and_save(first1, last1, first2, last2, first_min, buffer, buffer_end, comp, op, is_range1_A); bool const is_range_1_empty = buffer == buffer_end; BOOST_ASSERT(is_range_1_empty || (buffer_end-buffer) == (last1+l_block-unmerged)); if(is_range_1_empty){ buffer = buffer_end = buf_first; first_min = last_min - (last2 - first2); } else{ first_min = last_min; } BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(!is_range_1_empty || (last_min-first_min) == (last2-unmerged)); swap_and_update_key(next_key_idx != 0, key_next, key_range2, key_mid, first2, last2, first_min); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first_min, last_min, comp)); is_range1_A ^= is_range_1_empty; first1 = unmerged; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, unmerged, comp)); } BOOST_ASSERT( (is_range2_A && n_block_a_left) || (!is_range2_A && n_block_b_left)); is_range2_A ? --n_block_a_left : --n_block_b_left; last1 += l_block; first2 = last2; } RandIt res = op(forward_t(), buffer, buffer_end, first1); (void)res; BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, res, comp)); //////////////////////////////////////////////////////////////////////////// //Process irregular B block and remaining A blocks //////////////////////////////////////////////////////////////////////////// RandIt const last_irr2 = first_irr2 + l_irreg2; op(forward_t(), first_irr2, first_irr2+l_irreg2, buf_first); buffer = buf_first; buffer_end = buffer+l_irreg2; reverse_iterator<RandItBuf> rbuf_beg(buffer_end); RandIt dest = op_merge_blocks_with_irreg ( make_reverse_iterator(key_first + n_block_b + n_block_a), make_reverse_iterator(key_mid), inverse<KeyCompare>(key_comp) , make_reverse_iterator(first_irr2), rbuf_beg , make_reverse_iterator(buffer), make_reverse_iterator(last_irr2) , l_block, n_block_left, 0, n_block_left , inverse<Compare>(comp), true, op).base(); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(dest, last_irr2, comp)); buffer_end = rbuf_beg.base(); BOOST_ASSERT((dest-last1) == (buffer_end-buffer)); op_merge_with_left_placed(is_range1_A ? first1 : last1, last1, dest, buffer, buffer_end, comp, op); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(first, last_irr2, comp)); } template<class RandItKeys, class KeyCompare, class RandIt, class Compare, class RandItBuf> void merge_blocks_with_buf ( RandItKeys key_first , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const l_block , typename iterator_traits<RandIt>::size_type const l_irreg1 , typename iterator_traits<RandIt>::size_type const n_block_a , typename iterator_traits<RandIt>::size_type const n_block_b , typename iterator_traits<RandIt>::size_type const l_irreg2 , Compare comp , RandItBuf const buf_first , bool const xbuf_used) { if(xbuf_used){ op_merge_blocks_with_buf (key_first, key_comp, first, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, move_op(), buf_first); } else{ op_merge_blocks_with_buf (key_first, key_comp, first, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, swap_op(), buf_first); } } template<class RandIt, class Compare, class Op> typename iterator_traits<RandIt>::size_type op_insertion_sort_step_left ( RandIt const first , typename iterator_traits<RandIt>::size_type const length , typename iterator_traits<RandIt>::size_type const step , Compare comp, Op op) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const s = min_value<size_type>(step, AdaptiveSortInsertionSortThreshold); size_type m = 0; while((length - m) > s){ insertion_sort_op(first+m, first+m+s, first+m-s, comp, op); m += s; } insertion_sort_op(first+m, first+length, first+m-s, comp, op); return s; } template<class RandIt, class Compare> typename iterator_traits<RandIt>::size_type insertion_sort_step ( RandIt const first , typename iterator_traits<RandIt>::size_type const length , typename iterator_traits<RandIt>::size_type const step , Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const s = min_value<size_type>(step, AdaptiveSortInsertionSortThreshold); size_type m = 0; while((length - m) > s){ insertion_sort(first+m, first+m+s, comp); m += s; } insertion_sort(first+m, first+length, comp); return s; } template<class RandIt, class Compare, class Op> typename iterator_traits<RandIt>::size_type op_merge_left_step_multiple ( RandIt first_block , typename iterator_traits<RandIt>::size_type const elements_in_blocks , typename iterator_traits<RandIt>::size_type l_merged , typename iterator_traits<RandIt>::size_type const l_build_buf , typename iterator_traits<RandIt>::size_type l_left_space , Compare comp , Op op) { typedef typename iterator_traits<RandIt>::size_type size_type; for(; l_merged < l_build_buf && l_left_space >= l_merged; l_merged*=2){ size_type p0=0; RandIt pos = first_block; while((elements_in_blocks - p0) > 2*l_merged) { op_merge_left(pos-l_merged, pos, pos+l_merged, pos+2*l_merged, comp, op); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(pos-l_merged, pos+l_merged, comp)); p0 += 2*l_merged; pos = first_block+p0; } if((elements_in_blocks-p0) > l_merged) { op_merge_left(pos-l_merged, pos, pos+l_merged, first_block+elements_in_blocks, comp, op); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(pos-l_merged, pos-l_merged+(first_block+elements_in_blocks-pos), comp)); } else { op(forward_t(), pos, first_block+elements_in_blocks, pos-l_merged); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(pos-l_merged, first_block+elements_in_blocks-l_merged, comp)); } first_block -= l_merged; l_left_space -= l_merged; } return l_merged; } template<class RandIt, class Compare, class Op> void op_merge_right_step_once ( RandIt first_block , typename iterator_traits<RandIt>::size_type const elements_in_blocks , typename iterator_traits<RandIt>::size_type const l_build_buf , Compare comp , Op op) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type restk = elements_in_blocks%(2*l_build_buf); size_type p = elements_in_blocks - restk; BOOST_ASSERT(0 == (p%(2*l_build_buf))); if(restk <= l_build_buf){ op(backward_t(),first_block+p, first_block+p+restk, first_block+p+restk+l_build_buf); } else{ op_merge_right(first_block+p, first_block+p+l_build_buf, first_block+p+restk, first_block+p+restk+l_build_buf, comp, op); } while(p>0){ p -= 2*l_build_buf; op_merge_right(first_block+p, first_block+p+l_build_buf, first_block+p+2*l_build_buf, first_block+p+3*l_build_buf, comp, op); } } // build blocks of length 2*l_build_buf. l_build_buf is power of two // input: [0, l_build_buf) elements are buffer, rest unsorted elements // output: [0, l_build_buf) elements are buffer, blocks 2*l_build_buf and last subblock sorted // // First elements are merged from right to left until elements start // at first. All old elements [first, first + l_build_buf) are placed at the end // [first+len-l_build_buf, first+len). To achieve this: // - If we have external memory to merge, we save elements from the buffer // so that a non-swapping merge is used. Buffer elements are restored // at the end of the buffer from the external memory. // // - When the external memory is not available or it is insufficient // for a merge operation, left swap merging is used. // // Once elements are merged left to right in blocks of l_build_buf, then a single left // to right merge step is performed to achieve merged blocks of size 2K. // If external memory is available, usual merge is used, swap merging otherwise. // // As a last step, if auxiliary memory is available in-place merge is performed. // until all is merged or auxiliary memory is not large enough. template<class RandIt, class Compare, class XBuf> typename iterator_traits<RandIt>::size_type adaptive_sort_build_blocks ( RandIt const first , typename iterator_traits<RandIt>::size_type const len , typename iterator_traits<RandIt>::size_type const l_base , typename iterator_traits<RandIt>::size_type const l_build_buf , XBuf & xbuf , Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; BOOST_ASSERT(l_build_buf <= len); BOOST_ASSERT(0 == ((l_build_buf / l_base)&(l_build_buf/l_base-1))); //Place the start pointer after the buffer RandIt first_block = first + l_build_buf; size_type const elements_in_blocks = len - l_build_buf; ////////////////////////////////// // Start of merge to left step ////////////////////////////////// size_type l_merged = 0u; BOOST_ASSERT(l_build_buf); //If there is no enough buffer for the insertion sort step, just avoid the external buffer size_type kbuf = min_value<size_type>(l_build_buf, size_type(xbuf.capacity())); kbuf = kbuf < l_base ? 0 : kbuf; if(kbuf){ //Backup internal buffer values in external buffer so they can be overwritten xbuf.move_assign(first+l_build_buf-kbuf, kbuf); l_merged = op_insertion_sort_step_left(first_block, elements_in_blocks, l_base, comp, move_op()); //Now combine them using the buffer. Elements from buffer can be //overwritten since they've been saved to xbuf l_merged = op_merge_left_step_multiple ( first_block - l_merged, elements_in_blocks, l_merged, l_build_buf, kbuf - l_merged, comp, move_op()); //Restore internal buffer from external buffer unless kbuf was l_build_buf, //in that case restoration will happen later if(kbuf != l_build_buf){ boost::move(xbuf.data()+kbuf-l_merged, xbuf.data() + kbuf, first_block-l_merged+elements_in_blocks); } } else{ l_merged = insertion_sort_step(first_block, elements_in_blocks, l_base, comp); rotate_gcd(first_block - l_merged, first_block, first_block+elements_in_blocks); } //Now combine elements using the buffer. Elements from buffer can't be //overwritten since xbuf was not big enough, so merge swapping elements. l_merged = op_merge_left_step_multiple (first_block - l_merged, elements_in_blocks, l_merged, l_build_buf, l_build_buf - l_merged, comp, swap_op()); BOOST_ASSERT(l_merged == l_build_buf); ////////////////////////////////// // Start of merge to right step ////////////////////////////////// //If kbuf is l_build_buf then we can merge right without swapping //Saved data is still in xbuf if(kbuf && kbuf == l_build_buf){ op_merge_right_step_once(first, elements_in_blocks, l_build_buf, comp, move_op()); //Restore internal buffer from external buffer if kbuf was l_build_buf. //as this operation was previously delayed. boost::move(xbuf.data(), xbuf.data() + kbuf, first); } else{ op_merge_right_step_once(first, elements_in_blocks, l_build_buf, comp, swap_op()); } xbuf.clear(); //2*l_build_buf or total already merged return min_value(elements_in_blocks, 2*l_build_buf); } template<class RandItKeys, class KeyCompare, class RandIt, class Compare, class XBuf> void adaptive_sort_combine_blocks ( RandItKeys const keys , KeyCompare key_comp , RandIt const first , typename iterator_traits<RandIt>::size_type const len , typename iterator_traits<RandIt>::size_type const l_prev_merged , typename iterator_traits<RandIt>::size_type const l_block , bool const use_buf , bool const xbuf_used , XBuf & xbuf , Compare comp , bool merge_left) { (void)xbuf; typedef typename iterator_traits<RandIt>::size_type size_type; size_type const l_reg_combined = 2*l_prev_merged; size_type l_irreg_combined = 0; size_type const l_total_combined = calculate_total_combined(len, l_prev_merged, &l_irreg_combined); size_type const n_reg_combined = len/l_reg_combined; RandIt combined_first = first; (void)l_total_combined; BOOST_ASSERT(l_total_combined <= len); size_type const max_i = n_reg_combined + (l_irreg_combined != 0); if(merge_left || !use_buf) { for( size_type combined_i = 0; combined_i != max_i; ++combined_i, combined_first += l_reg_combined) { //Now merge blocks bool const is_last = combined_i==n_reg_combined; size_type const l_cur_combined = is_last ? l_irreg_combined : l_reg_combined; range_xbuf<RandIt, move_op> rbuf( (use_buf && xbuf_used) ? (combined_first-l_block) : combined_first, combined_first); size_type n_block_a, n_block_b, l_irreg1, l_irreg2; combine_params( keys, key_comp, l_cur_combined , l_prev_merged, l_block, rbuf , n_block_a, n_block_b, l_irreg1, l_irreg2); //Outputs BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A combpar: ", len + l_block); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(combined_first, combined_first + n_block_a*l_block+l_irreg1, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(combined_first + n_block_a*l_block+l_irreg1, combined_first + n_block_a*l_block+l_irreg1+n_block_b*l_block+l_irreg2, comp)); if(!use_buf){ merge_blocks_bufferless (keys, key_comp, combined_first, l_block, 0u, n_block_a, n_block_b, l_irreg2, comp); } else{ merge_blocks_left (keys, key_comp, combined_first, l_block, 0u, n_block_a, n_block_b, l_irreg2, comp, xbuf_used); } BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After merge_blocks_l: ", len + l_block); } } else{ combined_first += l_reg_combined*(max_i-1); for( size_type combined_i = max_i; combined_i--; combined_first -= l_reg_combined) { bool const is_last = combined_i==n_reg_combined; size_type const l_cur_combined = is_last ? l_irreg_combined : l_reg_combined; RandIt const combined_last(combined_first+l_cur_combined); range_xbuf<RandIt, move_op> rbuf(combined_last, xbuf_used ? (combined_last+l_block) : combined_last); size_type n_block_a, n_block_b, l_irreg1, l_irreg2; combine_params( keys, key_comp, l_cur_combined , l_prev_merged, l_block, rbuf , n_block_a, n_block_b, l_irreg1, l_irreg2); //Outputs BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A combpar: ", len + l_block); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(combined_first, combined_first + n_block_a*l_block+l_irreg1, comp)); BOOST_MOVE_ADAPTIVE_SORT_INVARIANT(is_sorted(combined_first + n_block_a*l_block+l_irreg1, combined_first + n_block_a*l_block+l_irreg1+n_block_b*l_block+l_irreg2, comp)); merge_blocks_right (keys, key_comp, combined_first, l_block, n_block_a, n_block_b, l_irreg2, comp, xbuf_used); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After merge_blocks_r: ", len + l_block); } } } //Returns true if buffer is placed in //[buffer+len-l_intbuf, buffer+len). Otherwise, buffer is //[buffer,buffer+l_intbuf) template<class RandIt, class Compare, class XBuf> bool adaptive_sort_combine_all_blocks ( RandIt keys , typename iterator_traits<RandIt>::size_type &n_keys , RandIt const buffer , typename iterator_traits<RandIt>::size_type const l_buf_plus_data , typename iterator_traits<RandIt>::size_type l_merged , typename iterator_traits<RandIt>::size_type &l_intbuf , XBuf & xbuf , Compare comp) { typedef typename iterator_traits<RandIt>::size_type size_type; RandIt const first = buffer + l_intbuf; size_type const l_data = l_buf_plus_data - l_intbuf; size_type const l_unique = l_intbuf+n_keys; //Backup data to external buffer once if possible bool const common_xbuf = l_data > l_merged && l_intbuf && l_intbuf <= xbuf.capacity(); if(common_xbuf){ xbuf.move_assign(buffer, l_intbuf); } bool prev_merge_left = true; size_type l_prev_total_combined = l_merged, l_prev_block = 0; bool prev_use_internal_buf = true; for( size_type n = 0; l_data > l_merged ; l_merged*=2 , ++n){ //If l_intbuf is non-zero, use that internal buffer. // Implies l_block == l_intbuf && use_internal_buf == true //If l_intbuf is zero, see if half keys can be reused as a reduced emergency buffer, // Implies l_block == n_keys/2 && use_internal_buf == true //Otherwise, just give up and and use all keys to merge using rotations (use_internal_buf = false) bool use_internal_buf = false; size_type const l_block = lblock_for_combine(l_intbuf, n_keys, 2*l_merged, use_internal_buf); BOOST_ASSERT(!l_intbuf || (l_block == l_intbuf)); BOOST_ASSERT(n == 0 || (!use_internal_buf || prev_use_internal_buf) ); BOOST_ASSERT(n == 0 || (!use_internal_buf || l_prev_block == l_block) ); bool const is_merge_left = (n&1) == 0; size_type const l_total_combined = calculate_total_combined(l_data, l_merged); if(n && prev_use_internal_buf && prev_merge_left){ if(is_merge_left || !use_internal_buf){ move_data_backward(first-l_prev_block, l_prev_total_combined, first, common_xbuf); } else{ //Put the buffer just after l_total_combined RandIt const buf_end = first+l_prev_total_combined; RandIt const buf_beg = buf_end-l_block; if(l_prev_total_combined > l_total_combined){ size_type const l_diff = l_prev_total_combined - l_total_combined; move_data_backward(buf_beg-l_diff, l_diff, buf_end-l_diff, common_xbuf); } else if(l_prev_total_combined < l_total_combined){ size_type const l_diff = l_total_combined - l_prev_total_combined; move_data_forward(buf_end, l_diff, buf_beg, common_xbuf); } } BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After move_data : ", l_data + l_intbuf); } //Combine to form l_merged*2 segments if(n_keys){ adaptive_sort_combine_blocks ( keys, comp, !use_internal_buf || is_merge_left ? first : first-l_block , l_data, l_merged, l_block, use_internal_buf, common_xbuf, xbuf, comp, is_merge_left); } else{ size_type *const uint_keys = xbuf.template aligned_trailing<size_type>(); adaptive_sort_combine_blocks ( uint_keys, less(), !use_internal_buf || is_merge_left ? first : first-l_block , l_data, l_merged, l_block, use_internal_buf, common_xbuf, xbuf, comp, is_merge_left); } BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After combine_blocks: ", l_data + l_intbuf); prev_merge_left = is_merge_left; l_prev_total_combined = l_total_combined; l_prev_block = l_block; prev_use_internal_buf = use_internal_buf; } BOOST_ASSERT(l_prev_total_combined == l_data); bool const buffer_right = prev_use_internal_buf && prev_merge_left; l_intbuf = prev_use_internal_buf ? l_prev_block : 0u; n_keys = l_unique - l_intbuf; //Restore data from to external common buffer if used if(common_xbuf){ if(buffer_right){ boost::move(xbuf.data(), xbuf.data() + l_intbuf, buffer+l_data); } else{ boost::move(xbuf.data(), xbuf.data() + l_intbuf, buffer); } } return buffer_right; } template<class RandIt, class Compare, class XBuf> void stable_merge ( RandIt first, RandIt const middle, RandIt last , Compare comp , XBuf &xbuf) { BOOST_ASSERT(xbuf.empty()); typedef typename iterator_traits<RandIt>::size_type size_type; size_type const len1 = size_type(middle-first); size_type const len2 = size_type(last-middle); size_type const l_min = min_value(len1, len2); if(xbuf.capacity() >= l_min){ buffered_merge(first, middle, last, comp, xbuf); xbuf.clear(); } else{ merge_bufferless(first, middle, last, comp); } } template<class RandIt, class Compare, class XBuf> void adaptive_sort_final_merge( bool buffer_right , RandIt const first , typename iterator_traits<RandIt>::size_type const l_intbuf , typename iterator_traits<RandIt>::size_type const n_keys , typename iterator_traits<RandIt>::size_type const len , XBuf & xbuf , Compare comp) { //BOOST_ASSERT(n_keys || xbuf.size() == l_intbuf); xbuf.clear(); typedef typename iterator_traits<RandIt>::size_type size_type; size_type const n_key_plus_buf = l_intbuf+n_keys; if(buffer_right){ stable_sort(first+len-l_intbuf, first+len, comp, xbuf); stable_merge(first+n_keys, first+len-l_intbuf, first+len, antistable<Compare>(comp), xbuf); stable_sort(first, first+n_keys, comp, xbuf); stable_merge(first, first+n_keys, first+len, comp, xbuf); } else{ stable_sort(first, first+n_key_plus_buf, comp, xbuf); if(xbuf.capacity() >= n_key_plus_buf){ buffered_merge(first, first+n_key_plus_buf, first+len, comp, xbuf); } else if(xbuf.capacity() >= min_value<size_type>(l_intbuf, n_keys)){ stable_merge(first+n_keys, first+n_key_plus_buf, first+len, comp, xbuf); stable_merge(first, first+n_keys, first+len, comp, xbuf); } else{ merge_bufferless(first, first+n_key_plus_buf, first+len, comp); } } BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After final_merge : ", len); } template<class RandIt, class Compare, class Unsigned, class XBuf> bool adaptive_sort_build_params (RandIt first, Unsigned const len, Compare comp , Unsigned &n_keys, Unsigned &l_intbuf, Unsigned &l_base, Unsigned &l_build_buf , XBuf & xbuf ) { typedef Unsigned size_type; //Calculate ideal parameters and try to collect needed unique keys l_base = 0u; //Try to find a value near sqrt(len) that is 2^N*l_base where //l_base <= AdaptiveSortInsertionSortThreshold. This property is important //as build_blocks merges to the left iteratively duplicating the //merged size and all the buffer must be used just before the final //merge to right step. This guarantees "build_blocks" produces //segments of size l_build_buf*2, maximizing the classic merge phase. l_intbuf = size_type(ceil_sqrt_multiple(len, &l_base)); //The internal buffer can be expanded if there is enough external memory while(xbuf.capacity() >= l_intbuf*2){ l_intbuf *= 2; } //This is the minimum number of keys to implement the ideal algorithm // //l_intbuf is used as buffer plus the key count size_type n_min_ideal_keys = l_intbuf-1; while(n_min_ideal_keys >= (len-l_intbuf-n_min_ideal_keys)/l_intbuf){ --n_min_ideal_keys; } n_min_ideal_keys += 1; BOOST_ASSERT(n_min_ideal_keys <= l_intbuf); if(xbuf.template supports_aligned_trailing<size_type>(l_intbuf, (len-l_intbuf-1)/l_intbuf+1)){ n_keys = 0u; l_build_buf = l_intbuf; } else{ //Try to achieve a l_build_buf of length l_intbuf*2, so that we can merge with that //l_intbuf*2 buffer in "build_blocks" and use half of them as buffer and the other half //as keys in combine_all_blocks. In that case n_keys >= n_min_ideal_keys but by a small margin. // //If available memory is 2*sqrt(l), then only sqrt(l) unique keys are needed, //(to be used for keys in combine_all_blocks) as the whole l_build_buf //will be backuped in the buffer during build_blocks. bool const non_unique_buf = xbuf.capacity() >= l_intbuf; size_type const to_collect = non_unique_buf ? n_min_ideal_keys : l_intbuf*2; size_type collected = collect_unique(first, first+len, to_collect, comp, xbuf); //If available memory is 2*sqrt(l), then for "build_params" //the situation is the same as if 2*l_intbuf were collected. if(non_unique_buf && collected == n_min_ideal_keys){ l_build_buf = l_intbuf; n_keys = n_min_ideal_keys; } else if(collected == 2*l_intbuf){ //l_intbuf*2 elements found. Use all of them in the build phase l_build_buf = l_intbuf*2; n_keys = l_intbuf; } else if(collected == (n_min_ideal_keys+l_intbuf)){ l_build_buf = l_intbuf; n_keys = n_min_ideal_keys; } //If collected keys are not enough, try to fix n_keys and l_intbuf. If no fix //is possible (due to very low unique keys), then go to a slow sort based on rotations. else{ BOOST_ASSERT(collected < (n_min_ideal_keys+l_intbuf)); if(collected < 4){ //No combination possible with less that 4 keys return false; } n_keys = l_intbuf; while(n_keys&(n_keys-1)){ n_keys &= n_keys-1; // make it power or 2 } while(n_keys > collected){ n_keys/=2; } //AdaptiveSortInsertionSortThreshold is always power of two so the minimum is power of two l_base = min_value<Unsigned>(n_keys, AdaptiveSortInsertionSortThreshold); l_intbuf = 0; l_build_buf = n_keys; } BOOST_ASSERT((n_keys+l_intbuf) >= l_build_buf); } return true; } template<class RandIt, class Compare, class XBuf> inline void adaptive_merge_combine_blocks( RandIt first , typename iterator_traits<RandIt>::size_type len1 , typename iterator_traits<RandIt>::size_type len2 , typename iterator_traits<RandIt>::size_type collected , typename iterator_traits<RandIt>::size_type n_keys , typename iterator_traits<RandIt>::size_type l_block , bool use_internal_buf , bool xbuf_used , Compare comp , XBuf & xbuf ) { typedef typename iterator_traits<RandIt>::size_type size_type; size_type const len = len1+len2; size_type const l_combine = len-collected; size_type const l_combine1 = len1-collected; if(n_keys){ RandIt const first_data = first+collected; RandIt const keys = first; BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A combine: ", len); if(xbuf_used){ if(xbuf.size() < l_block){ xbuf.initialize_until(l_block, *first); } BOOST_ASSERT(xbuf.size() >= l_block); size_type n_block_a, n_block_b, l_irreg1, l_irreg2; combine_params( keys, comp, l_combine , l_combine1, l_block, xbuf , n_block_a, n_block_b, l_irreg1, l_irreg2); //Outputs merge_blocks_with_buf (keys, comp, first_data, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, xbuf.data(), xbuf_used); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A mrg xbf: ", len); } else{ size_type n_block_a, n_block_b, l_irreg1, l_irreg2; combine_params( keys, comp, l_combine , l_combine1, l_block, xbuf , n_block_a, n_block_b, l_irreg1, l_irreg2); //Outputs if(use_internal_buf){ merge_blocks_with_buf (keys, comp, first_data, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, first_data-l_block, xbuf_used); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A mrg buf: ", len); } else{ merge_blocks_bufferless (keys, comp, first_data, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A mrg nbf: ", len); } } } else{ xbuf.shrink_to_fit(l_block); if(xbuf.size() < l_block){ xbuf.initialize_until(l_block, *first); } size_type *const uint_keys = xbuf.template aligned_trailing<size_type>(l_block); size_type n_block_a, n_block_b, l_irreg1, l_irreg2; combine_params( uint_keys, less(), l_combine , l_combine1, l_block, xbuf , n_block_a, n_block_b, l_irreg1, l_irreg2, true); //Outputs BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A combine: ", len); BOOST_ASSERT(xbuf.size() >= l_block); merge_blocks_with_buf (uint_keys, less(), first, l_block, l_irreg1, n_block_a, n_block_b, l_irreg2, comp, xbuf.data(), true); xbuf.clear(); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A mrg buf: ", len); } } template<class RandIt, class Compare, class XBuf> inline void adaptive_merge_final_merge( RandIt first , typename iterator_traits<RandIt>::size_type len1 , typename iterator_traits<RandIt>::size_type len2 , typename iterator_traits<RandIt>::size_type collected , typename iterator_traits<RandIt>::size_type l_intbuf , typename iterator_traits<RandIt>::size_type l_block , bool use_internal_buf , bool xbuf_used , Compare comp , XBuf & xbuf ) { typedef typename iterator_traits<RandIt>::size_type size_type; (void)l_block; size_type n_keys = collected-l_intbuf; size_type len = len1+len2; if(use_internal_buf){ if(xbuf_used){ xbuf.clear(); //Nothing to do if(n_keys){ stable_sort(first, first+n_keys, comp, xbuf); stable_merge(first, first+n_keys, first+len, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A key mrg: ", len); } } else{ xbuf.clear(); stable_sort(first, first+collected, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A k/b srt: ", len); stable_merge(first, first+collected, first+len, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A k/b mrg: ", len); } } else{ xbuf.clear(); stable_sort(first, first+collected, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A k/b srt: ", len); stable_merge(first, first+collected, first+len1+len2, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" A k/b mrg: ", len); } } template<class SizeType, class Xbuf> inline SizeType adaptive_merge_n_keys_intbuf(SizeType &rl_block, SizeType len1, SizeType len2, Xbuf & xbuf, SizeType &l_intbuf_inout) { typedef SizeType size_type; size_type l_block = rl_block; size_type l_intbuf = xbuf.capacity() >= l_block ? 0u : l_block; while(xbuf.capacity() >= l_block*2){ l_block *= 2; } //This is the minimum number of keys to implement the ideal algorithm size_type n_keys = len1/l_block+len2/l_block; while(n_keys >= ((len1-l_intbuf-n_keys)/l_block + len2/l_block)){ --n_keys; } ++n_keys; BOOST_ASSERT(n_keys >= ((len1-l_intbuf-n_keys)/l_block + len2/l_block)); if(xbuf.template supports_aligned_trailing<size_type>(l_block, n_keys)){ n_keys = 0u; } l_intbuf_inout = l_intbuf; rl_block = l_block; return n_keys; } /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// // Main explanation of the sort algorithm. // // csqrtlen = ceil(sqrt(len)); // // * First, 2*csqrtlen unique elements elements are extracted from elements to be // sorted and placed in the beginning of the range. // // * Step "build_blocks": In this nearly-classic merge step, 2*csqrtlen unique elements // will be used as auxiliary memory, so trailing len-2*csqrtlen elements are // are grouped in blocks of sorted 4*csqrtlen elements. At the end of the step // 2*csqrtlen unique elements are again the leading elements of the whole range. // // * Step "combine_blocks": pairs of previously formed blocks are merged with a different // ("smart") algorithm to form blocks of 8*csqrtlen elements. This step is slower than the // "build_blocks" step and repeated iteratively (forming blocks of 16*csqrtlen, 32*csqrtlen // elements, etc) of until all trailing (len-2*csqrtlen) elements are merged. // // In "combine_blocks" len/csqrtlen elements used are as "keys" (markers) to // know if elements belong to the first or second block to be merged and another // leading csqrtlen elements are used as buffer. Explanation of the "combine_blocks" step: // // Iteratively until all trailing (len-2*csqrtlen) elements are merged: // Iteratively for each pair of previously merged block: // * Blocks are divided groups of csqrtlen elements and // 2*merged_block/csqrtlen keys are sorted to be used as markers // * Groups are selection-sorted by first or last element (depending wheter they // merged to left or right) and keys are reordered accordingly as an imitation-buffer. // * Elements of each block pair are merged using the csqrtlen buffer taking into account // if they belong to the first half or second half (marked by the key). // // * In the final merge step leading elements (2*csqrtlen) are sorted and merged with // rotations with the rest of sorted elements in the "combine_blocks" step. // // Corner cases: // // * If no 2*csqrtlen elements can be extracted: // // * If csqrtlen+len/csqrtlen are extracted, then only csqrtlen elements are used // as buffer in the "build_blocks" step forming blocks of 2*csqrtlen elements. This // means that an additional "combine_blocks" step will be needed to merge all elements. // // * If no csqrtlen+len/csqrtlen elements can be extracted, but still more than a minimum, // then reduces the number of elements used as buffer and keys in the "build_blocks" // and "combine_blocks" steps. If "combine_blocks" has no enough keys due to this reduction // then uses a rotation based smart merge. // // * If the minimum number of keys can't be extracted, a rotation-based sorting is performed. // // * If auxiliary memory is more or equal than ceil(len/2), half-copying mergesort is used. // // * If auxiliary memory is more than csqrtlen+n_keys*sizeof(std::size_t), // then only csqrtlen elements need to be extracted and "combine_blocks" will use integral // keys to combine blocks. // // * If auxiliary memory is available, the "build_blocks" will be extended to build bigger blocks // using classic merge. template<class RandIt, class Compare, class XBuf> void adaptive_sort_impl ( RandIt first , typename iterator_traits<RandIt>::size_type const len , Compare comp , XBuf & xbuf ) { typedef typename iterator_traits<RandIt>::size_type size_type; //Small sorts go directly to insertion sort if(len <= size_type(AdaptiveSortInsertionSortThreshold)){ insertion_sort(first, first + len, comp); return; } if((len-len/2) <= xbuf.capacity()){ merge_sort(first, first+len, comp, xbuf.data()); return; } //Make sure it is at least four BOOST_STATIC_ASSERT(AdaptiveSortInsertionSortThreshold >= 4); size_type l_base = 0; size_type l_intbuf = 0; size_type n_keys = 0; size_type l_build_buf = 0; //Calculate and extract needed unique elements. If a minimum is not achieved //fallback to rotation-based merge if(!adaptive_sort_build_params(first, len, comp, n_keys, l_intbuf, l_base, l_build_buf, xbuf)){ stable_sort(first, first+len, comp, xbuf); return; } BOOST_ASSERT(l_build_buf); //Otherwise, continue the adaptive_sort BOOST_MOVE_ADAPTIVE_SORT_PRINT("\n After collect_unique: ", len); size_type const n_key_plus_buf = l_intbuf+n_keys; //l_build_buf is always power of two if l_intbuf is zero BOOST_ASSERT(l_intbuf || (0 == (l_build_buf & (l_build_buf-1)))); //Classic merge sort until internal buffer and xbuf are exhausted size_type const l_merged = adaptive_sort_build_blocks (first+n_key_plus_buf-l_build_buf, len-n_key_plus_buf+l_build_buf, l_base, l_build_buf, xbuf, comp); BOOST_MOVE_ADAPTIVE_SORT_PRINT(" After build_blocks: ", len); //Non-trivial merge bool const buffer_right = adaptive_sort_combine_all_blocks (first, n_keys, first+n_keys, len-n_keys, l_merged, l_intbuf, xbuf, comp); //Sort keys and buffer and merge the whole sequence adaptive_sort_final_merge(buffer_right, first, l_intbuf, n_keys, len, xbuf, comp); } // Main explanation of the merge algorithm. // // csqrtlen = ceil(sqrt(len)); // // * First, csqrtlen [to be used as buffer] + (len/csqrtlen - 1) [to be used as keys] => to_collect // unique elements are extracted from elements to be sorted and placed in the beginning of the range. // // * Step "combine_blocks": the leading (len1-to_collect) elements plus trailing len2 elements // are merged with a non-trivial ("smart") algorithm to form an ordered range trailing "len-to_collect" elements. // // Explanation of the "combine_blocks" step: // // * Trailing [first+to_collect, first+len1) elements are divided in groups of cqrtlen elements. // Remaining elements that can't form a group are grouped in front of those elements. // * Trailing [first+len1, first+len1+len2) elements are divided in groups of cqrtlen elements. // Remaining elements that can't form a group are grouped in the back of those elements. // * In parallel the following two steps are performed: // * Groups are selection-sorted by first or last element (depending wheter they // merged to left or right) and keys are reordered accordingly as an imitation-buffer. // * Elements of each block pair are merged using the csqrtlen buffer taking into account // if they belong to the first half or second half (marked by the key). // // * In the final merge step leading "to_collect" elements are merged with rotations // with the rest of merged elements in the "combine_blocks" step. // // Corner cases: // // * If no "to_collect" elements can be extracted: // // * If more than a minimum number of elements is extracted // then reduces the number of elements used as buffer and keys in the // and "combine_blocks" steps. If "combine_blocks" has no enough keys due to this reduction // then uses a rotation based smart merge. // // * If the minimum number of keys can't be extracted, a rotation-based merge is performed. // // * If auxiliary memory is more or equal than min(len1, len2), a buffered merge is performed. // // * If the len1 or len2 are less than 2*csqrtlen then a rotation-based merge is performed. // // * If auxiliary memory is more than csqrtlen+n_keys*sizeof(std::size_t), // then no csqrtlen need to be extracted and "combine_blocks" will use integral // keys to combine blocks. template<class RandIt, class Compare, class XBuf> void adaptive_merge_impl ( RandIt first , typename iterator_traits<RandIt>::size_type const len1 , typename iterator_traits<RandIt>::size_type const len2 , Compare comp , XBuf & xbuf ) { typedef typename iterator_traits<RandIt>::size_type size_type; if(xbuf.capacity() >= min_value<size_type>(len1, len2)){ buffered_merge(first, first+len1, first+(len1+len2), comp, xbuf); } else{ const size_type len = len1+len2; //Calculate ideal parameters and try to collect needed unique keys size_type l_block = size_type(ceil_sqrt(len)); //One range is not big enough to extract keys and the internal buffer so a //rotation-based based merge will do just fine if(len1 <= l_block*2 || len2 <= l_block*2){ merge_bufferless(first, first+len1, first+len1+len2, comp); return; } //Detail the number of keys and internal buffer. If xbuf has enough memory, no //internal buffer is needed so l_intbuf will remain 0. size_type l_intbuf = 0; size_type n_keys = adaptive_merge_n_keys_intbuf(l_block, len1, len2, xbuf, l_intbuf); size_type const to_collect = l_intbuf+n_keys; //Try to extract needed unique values from the first range size_type const collected = collect_unique(first, first+len1, to_collect, comp, xbuf); BOOST_MOVE_ADAPTIVE_SORT_PRINT("\n A collect: ", len); //Not the minimum number of keys is not available on the first range, so fallback to rotations if(collected != to_collect && collected < 4){ merge_bufferless(first, first+len1, first+len1+len2, comp); return; } //If not enough keys but more than minimum, adjust the internal buffer and key count bool use_internal_buf = collected == to_collect; if (!use_internal_buf){ l_intbuf = 0u; n_keys = collected; l_block = lblock_for_combine(l_intbuf, n_keys, len, use_internal_buf); //If use_internal_buf is false, then then internal buffer will be zero and rotation-based combination will be used l_intbuf = use_internal_buf ? l_block : 0u; } bool const xbuf_used = collected == to_collect && xbuf.capacity() >= l_block; //Merge trailing elements using smart merges adaptive_merge_combine_blocks(first, len1, len2, collected, n_keys, l_block, use_internal_buf, xbuf_used, comp, xbuf); //Merge buffer and keys with the rest of the values adaptive_merge_final_merge (first, len1, len2, collected, l_intbuf, l_block, use_internal_buf, xbuf_used, comp, xbuf); } } } //namespace detail_adaptive { } //namespace movelib { } //namespace boost { #include <boost/move/detail/config_end.hpp> #endif //#define BOOST_MOVE_ADAPTIVE_SORT_MERGE_HPP