--- /dev/null
+// -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file parallel/losertree.h
+* @brief Many generic loser tree variants.
+* This file is a GNU parallel extension to the Standard C++ Library.
+*/
+
+// Written by Johannes Singler.
+
+#ifndef _GLIBCXX_PARALLEL_LOSERTREE_H
+#define _GLIBCXX_PARALLEL_LOSERTREE_H 1
+
+#include <bits/stl_algobase.h>
+#include <bits/stl_function.h>
+#include <parallel/features.h>
+#include <parallel/base.h>
+
+namespace __gnu_parallel
+{
+ /**
+ * @brief Guarded loser/tournament tree.
+ *
+ * The smallest element is at the top.
+ *
+ * Guarding is done explicitly through one flag _M_sup per element,
+ * inf is not needed due to a better initialization routine. This
+ * is a well-performing variant.
+ *
+ * @param _Tp the element type
+ * @param _Compare the comparator to use, defaults to std::less<_Tp>
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreeBase
+ {
+ protected:
+ /** @brief Internal representation of a _LoserTree element. */
+ struct _Loser
+ {
+ /** @brief flag, true iff this is a "maximum" __sentinel. */
+ bool _M_sup;
+ /** @brief __index of the __source __sequence. */
+ int _M_source;
+ /** @brief _M_key of the element in the _LoserTree. */
+ _Tp _M_key;
+ };
+
+ unsigned int _M_ik, _M_k, _M_offset;
+
+ /** log_2{_M_k} */
+ unsigned int _M_log_k;
+
+ /** @brief _LoserTree __elements. */
+ _Loser* _M_losers;
+
+ /** @brief _Compare to use. */
+ _Compare _M_comp;
+
+ /**
+ * @brief State flag that determines whether the _LoserTree is empty.
+ *
+ * Only used for building the _LoserTree.
+ */
+ bool _M_first_insert;
+
+ public:
+ /**
+ * @brief The constructor.
+ *
+ * @param __k The number of sequences to merge.
+ * @param __comp The comparator to use.
+ */
+ _LoserTreeBase(unsigned int __k, _Compare __comp)
+ : _M_comp(__comp)
+ {
+ _M_ik = __k;
+
+ // Compute log_2{_M_k} for the _Loser Tree
+ _M_log_k = __rd_log2(_M_ik - 1) + 1;
+
+ // Next greater power of 2.
+ _M_k = 1 << _M_log_k;
+ _M_offset = _M_k;
+
+ // Avoid default-constructing _M_losers[]._M_key
+ _M_losers = static_cast<_Loser*>(::operator new(2 * _M_k
+ * sizeof(_Loser)));
+ for (unsigned int __i = _M_ik - 1; __i < _M_k; ++__i)
+ _M_losers[__i + _M_k]._M_sup = true;
+
+ _M_first_insert = true;
+ }
+
+ /**
+ * @brief The destructor.
+ */
+ ~_LoserTreeBase()
+ {
+ for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+ _M_losers[__i].~_Loser();
+ ::operator delete(_M_losers);
+ }
+
+ /**
+ * @brief Initializes the sequence "_M_source" with the element "__key".
+ *
+ * @param __key the element to insert
+ * @param __source __index of the __source __sequence
+ * @param __sup flag that determines whether the value to insert is an
+ * explicit __supremum.
+ */
+ void
+ __insert_start(const _Tp& __key, int __source, bool __sup)
+ {
+ unsigned int __pos = _M_k + __source;
+
+ if (_M_first_insert)
+ {
+ // Construct all keys, so we can easily destruct them.
+ for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+ ::new(&(_M_losers[__i]._M_key)) _Tp(__key);
+ _M_first_insert = false;
+ }
+ else
+ _M_losers[__pos]._M_key = __key;
+
+ _M_losers[__pos]._M_sup = __sup;
+ _M_losers[__pos]._M_source = __source;
+ }
+
+ /**
+ * @return the index of the sequence with the smallest element.
+ */
+ int __get_min_source()
+ { return _M_losers[0]._M_source; }
+ };
+
+ /**
+ * @brief Stable _LoserTree variant.
+ *
+ * Provides the stable implementations of insert_start, __init_winner,
+ * __init and __delete_min_insert.
+ *
+ * Unstable variant is done using partial specialisation below.
+ */
+ template<bool __stable/* default == true */, typename _Tp,
+ typename _Compare>
+ class _LoserTree
+ : public _LoserTreeBase<_Tp, _Compare>
+ {
+ typedef _LoserTreeBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+ using _Base::_M_first_insert;
+
+ public:
+ _LoserTree(unsigned int __k, _Compare __comp)
+ : _Base::_LoserTreeBase(__k, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (_M_losers[__right]._M_sup
+ || (!_M_losers[__left]._M_sup
+ && !_M_comp(_M_losers[__right]._M_key,
+ _M_losers[__left]._M_key)))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void __init()
+ { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+ /**
+ * @brief Delete the smallest element and insert a new element from
+ * the previously smallest element's sequence.
+ *
+ * This implementation is stable.
+ */
+ // Do not pass a const reference since __key will be used as
+ // local variable.
+ void
+ __delete_min_insert(_Tp __key, bool __sup)
+ {
+ using std::swap;
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted, ties are broken by _M_source.
+ if ((__sup && (!_M_losers[__pos]._M_sup
+ || _M_losers[__pos]._M_source < __source))
+ || (!__sup && !_M_losers[__pos]._M_sup
+ && ((_M_comp(_M_losers[__pos]._M_key, __key))
+ || (!_M_comp(__key, _M_losers[__pos]._M_key)
+ && _M_losers[__pos]._M_source < __source))))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_sup, __sup);
+ std::swap(_M_losers[__pos]._M_source, __source);
+ swap(_M_losers[__pos]._M_key, __key);
+ }
+ }
+
+ _M_losers[0]._M_sup = __sup;
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_key = __key;
+ }
+ };
+
+ /**
+ * @brief Unstable _LoserTree variant.
+ *
+ * Stability (non-stable here) is selected with partial specialization.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTree</* __stable == */false, _Tp, _Compare>
+ : public _LoserTreeBase<_Tp, _Compare>
+ {
+ typedef _LoserTreeBase<_Tp, _Compare> _Base;
+ using _Base::_M_log_k;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+ using _Base::_M_first_insert;
+
+ public:
+ _LoserTree(unsigned int __k, _Compare __comp)
+ : _Base::_LoserTreeBase(__k, __comp)
+ { }
+
+ /**
+ * Computes the winner of the competition at position "__root".
+ *
+ * Called recursively (starting at 0) to build the initial tree.
+ *
+ * @param __root __index of the "game" to start.
+ */
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (_M_losers[__right]._M_sup
+ || (!_M_losers[__left]._M_sup
+ && !_M_comp(_M_losers[__right]._M_key,
+ _M_losers[__left]._M_key)))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void
+ __init()
+ { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+ /**
+ * Delete the _M_key smallest element and insert the element __key
+ * instead.
+ *
+ * @param __key the _M_key to insert
+ * @param __sup true iff __key is an explicitly marked supremum
+ */
+ // Do not pass a const reference since __key will be used as local
+ // variable.
+ void
+ __delete_min_insert(_Tp __key, bool __sup)
+ {
+ using std::swap;
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted.
+ if (__sup || (!_M_losers[__pos]._M_sup
+ && _M_comp(_M_losers[__pos]._M_key, __key)))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_sup, __sup);
+ std::swap(_M_losers[__pos]._M_source, __source);
+ swap(_M_losers[__pos]._M_key, __key);
+ }
+ }
+
+ _M_losers[0]._M_sup = __sup;
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_key = __key;
+ }
+ };
+
+ /**
+ * @brief Base class of _Loser Tree implementation using pointers.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreePointerBase
+ {
+ protected:
+ /** @brief Internal representation of _LoserTree __elements. */
+ struct _Loser
+ {
+ bool _M_sup;
+ int _M_source;
+ const _Tp* _M_keyp;
+ };
+
+ unsigned int _M_ik, _M_k, _M_offset;
+ _Loser* _M_losers;
+ _Compare _M_comp;
+
+ public:
+ _LoserTreePointerBase(unsigned int __k,
+ _Compare __comp = std::less<_Tp>())
+ : _M_comp(__comp)
+ {
+ _M_ik = __k;
+
+ // Next greater power of 2.
+ _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+ _M_offset = _M_k;
+ _M_losers = new _Loser[_M_k * 2];
+ for (unsigned int __i = _M_ik - 1; __i < _M_k; __i++)
+ _M_losers[__i + _M_k]._M_sup = true;
+ }
+
+ ~_LoserTreePointerBase()
+ { delete[] _M_losers; }
+
+ int __get_min_source()
+ { return _M_losers[0]._M_source; }
+
+ void __insert_start(const _Tp& __key, int __source, bool __sup)
+ {
+ unsigned int __pos = _M_k + __source;
+
+ _M_losers[__pos]._M_sup = __sup;
+ _M_losers[__pos]._M_source = __source;
+ _M_losers[__pos]._M_keyp = &__key;
+ }
+ };
+
+ /**
+ * @brief Stable _LoserTree implementation.
+ *
+ * The unstable variant is implemented using partial instantiation below.
+ */
+ template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+ class _LoserTreePointer
+ : public _LoserTreePointerBase<_Tp, _Compare>
+ {
+ typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreePointerBase(__k, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (_M_losers[__right]._M_sup
+ || (!_M_losers[__left]._M_sup
+ && !_M_comp(*_M_losers[__right]._M_keyp,
+ *_M_losers[__left]._M_keyp)))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void __init()
+ { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+ void __delete_min_insert(const _Tp& __key, bool __sup)
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ const _Tp* __keyp = &__key;
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted, ties are broken by __source.
+ if ((__sup && (!_M_losers[__pos]._M_sup
+ || _M_losers[__pos]._M_source < __source))
+ || (!__sup && !_M_losers[__pos]._M_sup &&
+ ((_M_comp(*_M_losers[__pos]._M_keyp, *__keyp))
+ || (!_M_comp(*__keyp, *_M_losers[__pos]._M_keyp)
+ && _M_losers[__pos]._M_source < __source))))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_sup, __sup);
+ std::swap(_M_losers[__pos]._M_source, __source);
+ std::swap(_M_losers[__pos]._M_keyp, __keyp);
+ }
+ }
+
+ _M_losers[0]._M_sup = __sup;
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_keyp = __keyp;
+ }
+ };
+
+ /**
+ * @brief Unstable _LoserTree implementation.
+ *
+ * The stable variant is above.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreePointer</* __stable == */false, _Tp, _Compare>
+ : public _LoserTreePointerBase<_Tp, _Compare>
+ {
+ typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreePointerBase(__k, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (_M_losers[__right]._M_sup
+ || (!_M_losers[__left]._M_sup
+ && !_M_comp(*_M_losers[__right]._M_keyp,
+ *_M_losers[__left]._M_keyp)))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void __init()
+ { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+ void __delete_min_insert(const _Tp& __key, bool __sup)
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ const _Tp* __keyp = &__key;
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted.
+ if (__sup || (!_M_losers[__pos]._M_sup
+ && _M_comp(*_M_losers[__pos]._M_keyp, *__keyp)))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_sup, __sup);
+ std::swap(_M_losers[__pos]._M_source, __source);
+ std::swap(_M_losers[__pos]._M_keyp, __keyp);
+ }
+ }
+
+ _M_losers[0]._M_sup = __sup;
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_keyp = __keyp;
+ }
+ };
+
+ /** @brief Base class for unguarded _LoserTree implementation.
+ *
+ * The whole element is copied into the tree structure.
+ *
+ * No guarding is done, therefore not a single input sequence must
+ * run empty. Unused __sequence heads are marked with a sentinel which
+ * is > all elements that are to be merged.
+ *
+ * This is a very fast variant.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreeUnguardedBase
+ {
+ protected:
+ struct _Loser
+ {
+ int _M_source;
+ _Tp _M_key;
+ };
+
+ unsigned int _M_ik, _M_k, _M_offset;
+ _Loser* _M_losers;
+ _Compare _M_comp;
+
+ public:
+ _LoserTreeUnguardedBase(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _M_comp(__comp)
+ {
+ _M_ik = __k;
+
+ // Next greater power of 2.
+ _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+ _M_offset = _M_k;
+ // Avoid default-constructing _M_losers[]._M_key
+ _M_losers = static_cast<_Loser*>(::operator new(2 * _M_k
+ * sizeof(_Loser)));
+
+ for (unsigned int __i = 0; __i < _M_k; ++__i)
+ {
+ ::new(&(_M_losers[__i]._M_key)) _Tp(__sentinel);
+ _M_losers[__i]._M_source = -1;
+ }
+ for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
+ {
+ ::new(&(_M_losers[__i]._M_key)) _Tp(__sentinel);
+ _M_losers[__i]._M_source = -1;
+ }
+ }
+
+ ~_LoserTreeUnguardedBase()
+ {
+ for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+ _M_losers[__i].~_Loser();
+ ::operator delete(_M_losers);
+ }
+
+ int
+ __get_min_source()
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ return _M_losers[0]._M_source;
+ }
+
+ void
+ __insert_start(const _Tp& __key, int __source, bool)
+ {
+ unsigned int __pos = _M_k + __source;
+
+ ::new(&(_M_losers[__pos]._M_key)) _Tp(__key);
+ _M_losers[__pos]._M_source = __source;
+ }
+ };
+
+ /**
+ * @brief Stable implementation of unguarded _LoserTree.
+ *
+ * Unstable variant is selected below with partial specialization.
+ */
+ template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+ class _LoserTreeUnguarded
+ : public _LoserTreeUnguardedBase<_Tp, _Compare>
+ {
+ typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreeUnguarded(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreeUnguardedBase(__k, __sentinel, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (!_M_comp(_M_losers[__right]._M_key,
+ _M_losers[__left]._M_key))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void
+ __init()
+ {
+ _M_losers[0] = _M_losers[__init_winner(1)];
+
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top at the beginning
+ // (0 sequences!)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ }
+
+ // Do not pass a const reference since __key will be used as
+ // local variable.
+ void
+ __delete_min_insert(_Tp __key, bool)
+ {
+ using std::swap;
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted, ties are broken by _M_source.
+ if (_M_comp(_M_losers[__pos]._M_key, __key)
+ || (!_M_comp(__key, _M_losers[__pos]._M_key)
+ && _M_losers[__pos]._M_source < __source))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_source, __source);
+ swap(_M_losers[__pos]._M_key, __key);
+ }
+ }
+
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_key = __key;
+ }
+ };
+
+ /**
+ * @brief Non-Stable implementation of unguarded _LoserTree.
+ *
+ * Stable implementation is above.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreeUnguarded</* __stable == */false, _Tp, _Compare>
+ : public _LoserTreeUnguardedBase<_Tp, _Compare>
+ {
+ typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreeUnguarded(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreeUnguardedBase(__k, __sentinel, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+
+#if _GLIBCXX_ASSERTIONS
+ // If __left one is sentinel then __right one must be, too.
+ if (_M_losers[__left]._M_source == -1)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
+#endif
+
+ if (!_M_comp(_M_losers[__right]._M_key,
+ _M_losers[__left]._M_key))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void
+ __init()
+ {
+ _M_losers[0] = _M_losers[__init_winner(1)];
+
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top at the beginning
+ // (0 sequences!)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ }
+
+ // Do not pass a const reference since __key will be used as
+ // local variable.
+ void
+ __delete_min_insert(_Tp __key, bool)
+ {
+ using std::swap;
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted.
+ if (_M_comp(_M_losers[__pos]._M_key, __key))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_source, __source);
+ swap(_M_losers[__pos]._M_key, __key);
+ }
+ }
+
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_key = __key;
+ }
+ };
+
+ /** @brief Unguarded loser tree, keeping only pointers to the
+ * elements in the tree structure.
+ *
+ * No guarding is done, therefore not a single input sequence must
+ * run empty. This is a very fast variant.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreePointerUnguardedBase
+ {
+ protected:
+ struct _Loser
+ {
+ int _M_source;
+ const _Tp* _M_keyp;
+ };
+
+ unsigned int _M_ik, _M_k, _M_offset;
+ _Loser* _M_losers;
+ _Compare _M_comp;
+
+ public:
+
+ _LoserTreePointerUnguardedBase(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _M_comp(__comp)
+ {
+ _M_ik = __k;
+
+ // Next greater power of 2.
+ _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+ _M_offset = _M_k;
+ // Avoid default-constructing _M_losers[]._M_key
+ _M_losers = new _Loser[2 * _M_k];
+
+ for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
+ {
+ _M_losers[__i]._M_keyp = &__sentinel;
+ _M_losers[__i]._M_source = -1;
+ }
+ }
+
+ ~_LoserTreePointerUnguardedBase()
+ { delete[] _M_losers; }
+
+ int
+ __get_min_source()
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ return _M_losers[0]._M_source;
+ }
+
+ void
+ __insert_start(const _Tp& __key, int __source, bool)
+ {
+ unsigned int __pos = _M_k + __source;
+
+ _M_losers[__pos]._M_keyp = &__key;
+ _M_losers[__pos]._M_source = __source;
+ }
+ };
+
+ /**
+ * @brief Stable unguarded _LoserTree variant storing pointers.
+ *
+ * Unstable variant is implemented below using partial specialization.
+ */
+ template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+ class _LoserTreePointerUnguarded
+ : public _LoserTreePointerUnguardedBase<_Tp, _Compare>
+ {
+ typedef _LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreePointerUnguarded(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreePointerUnguardedBase(__k, __sentinel, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+ if (!_M_comp(*_M_losers[__right]._M_keyp,
+ *_M_losers[__left]._M_keyp))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void
+ __init()
+ {
+ _M_losers[0] = _M_losers[__init_winner(1)];
+
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top at the beginning
+ // (0 sequences!)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ }
+
+ void
+ __delete_min_insert(const _Tp& __key, bool __sup)
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ const _Tp* __keyp = &__key;
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted, ties are broken by _M_source.
+ if (_M_comp(*_M_losers[__pos]._M_keyp, *__keyp)
+ || (!_M_comp(*__keyp, *_M_losers[__pos]._M_keyp)
+ && _M_losers[__pos]._M_source < __source))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_source, __source);
+ std::swap(_M_losers[__pos]._M_keyp, __keyp);
+ }
+ }
+
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_keyp = __keyp;
+ }
+ };
+
+ /**
+ * @brief Unstable unguarded _LoserTree variant storing pointers.
+ *
+ * Stable variant is above.
+ */
+ template<typename _Tp, typename _Compare>
+ class _LoserTreePointerUnguarded</* __stable == */false, _Tp, _Compare>
+ : public _LoserTreePointerUnguardedBase<_Tp, _Compare>
+ {
+ typedef _LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
+ using _Base::_M_k;
+ using _Base::_M_comp;
+ using _Base::_M_losers;
+
+ public:
+ _LoserTreePointerUnguarded(unsigned int __k, const _Tp& __sentinel,
+ _Compare __comp = std::less<_Tp>())
+ : _Base::_LoserTreePointerUnguardedBase(__k, __sentinel, __comp)
+ { }
+
+ unsigned int
+ __init_winner(unsigned int __root)
+ {
+ if (__root >= _M_k)
+ return __root;
+ else
+ {
+ unsigned int __left = __init_winner(2 * __root);
+ unsigned int __right = __init_winner(2 * __root + 1);
+
+#if _GLIBCXX_ASSERTIONS
+ // If __left one is sentinel then __right one must be, too.
+ if (_M_losers[__left]._M_source == -1)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
+#endif
+
+ if (!_M_comp(*_M_losers[__right]._M_keyp,
+ *_M_losers[__left]._M_keyp))
+ {
+ // Left one is less or equal.
+ _M_losers[__root] = _M_losers[__right];
+ return __left;
+ }
+ else
+ {
+ // Right one is less.
+ _M_losers[__root] = _M_losers[__left];
+ return __right;
+ }
+ }
+ }
+
+ void
+ __init()
+ {
+ _M_losers[0] = _M_losers[__init_winner(1)];
+
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top at the beginning
+ // (0 sequences!)
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+ }
+
+ void
+ __delete_min_insert(const _Tp& __key, bool __sup)
+ {
+#if _GLIBCXX_ASSERTIONS
+ // no dummy sequence can ever be at the top!
+ _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+
+ const _Tp* __keyp = &__key;
+ int __source = _M_losers[0]._M_source;
+ for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+ __pos /= 2)
+ {
+ // The smaller one gets promoted.
+ if (_M_comp(*(_M_losers[__pos]._M_keyp), *__keyp))
+ {
+ // The other one is smaller.
+ std::swap(_M_losers[__pos]._M_source, __source);
+ std::swap(_M_losers[__pos]._M_keyp, __keyp);
+ }
+ }
+
+ _M_losers[0]._M_source = __source;
+ _M_losers[0]._M_keyp = __keyp;
+ }
+ };
+} // namespace __gnu_parallel
+
+#endif /* _GLIBCXX_PARALLEL_LOSERTREE_H */
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