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author | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
commit | 1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch) | |
tree | c607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/libstdc++-v3/include/parallel/losertree.h | |
parent | 283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff) | |
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Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/libstdc++-v3/include/parallel/losertree.h')
-rw-r--r-- | gcc-4.9/libstdc++-v3/include/parallel/losertree.h | 1063 |
1 files changed, 1063 insertions, 0 deletions
diff --git a/gcc-4.9/libstdc++-v3/include/parallel/losertree.h b/gcc-4.9/libstdc++-v3/include/parallel/losertree.h new file mode 100644 index 0000000..04b1e45 --- /dev/null +++ b/gcc-4.9/libstdc++-v3/include/parallel/losertree.h @@ -0,0 +1,1063 @@ +// -*- C++ -*- + +// Copyright (C) 2007-2014 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 */ |