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461 lines
13 KiB
461 lines
13 KiB
/*==LICENSE==* |
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CyanWorlds.com Engine - MMOG client, server and tools |
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Copyright (C) 2011 Cyan Worlds, Inc. |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. |
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You can contact Cyan Worlds, Inc. by email legal@cyan.com |
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or by snail mail at: |
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Cyan Worlds, Inc. |
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14617 N Newport Hwy |
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Mead, WA 99021 |
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*==LICENSE==*/ |
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/***************************************************************************** |
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* |
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* $/Plasma20/Sources/Plasma/NucleusLib/pnUtils/Private/pnUtSkipList.h |
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* |
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***/ |
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#ifdef PLASMA20_SOURCES_PLASMA_NUCLEUSLIB_PNUTILS_PRIVATE_PNUTSKIPLIST_H |
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#error "Header $/Plasma20/Sources/Plasma/NucleusLib/pnUtils/Private/pnUtSkipList.h included more than once" |
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#endif |
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#define PLASMA20_SOURCES_PLASMA_NUCLEUSLIB_PNUTILS_PRIVATE_PNUTSKIPLIST_H |
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/***************************************************************************** |
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* |
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* Macros |
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* |
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***/ |
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#define SKIPLIST(type, keyType, keyField, cmp) TSkipList< type, keyType, offsetof(type, keyField), cmp > |
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#define SKIPLIST_NUMERIC(type, keyType, keyField) SKIPLIST(type, keyType, keyField, TSkipListNumericCmp<keyType>) |
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#define SKIPLIST_STRING(type, keyType, keyField) SKIPLIST(type, keyType, keyField, TSkipListStringCmp<keyType>) |
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#define SKIPLIST_STRINGI(type, keyType, keyField) SKIPLIST(type, keyType, keyField, TSkipListStringCmpI<keyType>) |
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/***************************************************************************** |
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* |
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* Typedefs |
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* |
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***/ |
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typedef void * SkipListTag; |
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/***************************************************************************** |
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* |
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* Comparers |
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* |
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***/ |
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template<class K> |
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class TSkipListNumericCmp { |
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public: |
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static bool Eq (const K & a, const K & b) { return a == b; } |
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static bool Lt (const K & a, const K & b) { return a < b; } |
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}; |
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template<class K> |
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class TSkipListStringCmp { |
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public: |
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static bool Eq (const K & a, const K & b) { return StrCmp(a, b, (unsigned)-1) == 0; } |
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static bool Lt (const K & a, const K & b) { return StrCmp(a, b, (unsigned)-1) < 0; } |
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}; |
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template<class K> |
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class TSkipListStringCmpI { |
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public: |
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static bool Eq (const K & a, const K & b) { return StrCmpI(a, b, (unsigned)-1) == 0; } |
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static bool Lt (const K & a, const K & b) { return StrCmpI(a, b, (unsigned)-1) < 0; } |
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}; |
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/***************************************************************************** |
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* |
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* TSkipList |
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* |
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***/ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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class TSkipList { |
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private: |
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enum { kMaxLevels = 32 }; |
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template<class T, class K> |
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struct TNode { |
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const K * key; |
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T * object; |
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unsigned level; |
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TNode<T, K> * prev; |
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TNode<T, K> * next[1]; // variable size array |
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}; |
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typedef TNode<T,K> Node; |
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unsigned m_level; |
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Node * m_head; |
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Node * m_stop; |
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unsigned m_randomBits; |
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unsigned m_randomsLeft; |
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Node * AllocNode (unsigned levels); |
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void FreeNode (Node * node); |
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unsigned RandomLevel (); |
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public: |
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inline TSkipList (); |
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inline ~TSkipList (); |
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inline void Clear (); |
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inline void Delete (T * object); |
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inline T * Find (const K & key, SkipListTag * tag = nil) const; |
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inline T * FindNext (SkipListTag * tag) const; |
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inline T * Head (SkipListTag * tag) const; |
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inline T * Next (SkipListTag * tag) const; |
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inline T * Prev (SkipListTag * tag) const; |
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inline T * Tail (SkipListTag * tag) const; |
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inline void Link (T * object); |
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inline void Unlink (T * object); |
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inline void Unlink (SkipListTag * tag); |
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inline void UnlinkAll (); |
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#ifdef HS_DEBUGGING |
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inline void Print () const; |
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#endif |
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}; |
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/***************************************************************************** |
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* |
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* TSkipList private member functions |
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* |
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***/ |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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typename TSkipList<T,K,keyOffset,Cmp>::TNode<T,K> * TSkipList<T,K,keyOffset,Cmp>::AllocNode (unsigned level) { |
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unsigned size = offsetof(Node, next) + (level + 1) * sizeof(Node); |
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Node * node = (Node *)ALLOC(size); |
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node->level = level; |
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return node; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::FreeNode (TNode<T,K> * node) { |
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FREE(node); |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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unsigned TSkipList<T,K,keyOffset,Cmp>::RandomLevel () { |
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unsigned level = 0; |
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unsigned bits = 0; |
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while (!bits) { |
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bits = m_randomBits % 4; |
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if (!bits) |
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++level; |
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m_randomBits >>= 2; |
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m_randomsLeft -= 2; |
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if (!m_randomsLeft) { |
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m_randomBits = RandUnsigned(); |
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m_randomsLeft = 30; |
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} |
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} |
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return level; |
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} |
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/***************************************************************************** |
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* |
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* TSkipList public member functions |
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* |
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***/ |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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TSkipList<T,K,keyOffset,Cmp>::TSkipList () { |
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m_level = 0; |
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m_head = AllocNode(kMaxLevels); |
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m_stop = AllocNode(0); |
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m_randomBits = RandUnsigned(); |
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m_randomsLeft = 30; |
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// Initialize header and stop skip node pointers |
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m_stop->prev = m_head; |
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m_stop->object = nil; |
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m_stop->next[0] = nil; |
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m_head->object = nil; |
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for (unsigned index = 0; index < kMaxLevels; ++index) |
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m_head->next[index] = m_stop; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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TSkipList<T,K,keyOffset,Cmp>::~TSkipList () { |
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UnlinkAll(); |
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ASSERT(m_stop->prev == m_head); |
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FreeNode(m_head); |
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FreeNode(m_stop); |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::Clear () { |
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Node * ptr = m_head->next[0]; |
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while (ptr != m_stop) { |
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Node * next = ptr->next[0]; |
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DEL(ptr->object); |
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FreeNode(ptr); |
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ptr = next; |
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} |
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m_stop->prev = m_head; |
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for (unsigned index = 0; index < kMaxLevels; ++index) |
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m_head->next[index] = m_stop; |
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m_level = 0; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::Delete (T * object) { |
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Unlink(object); |
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DEL(object); |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::Find (const K & key, SkipListTag * tag) const { |
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Node * node = m_head; |
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m_stop->key = &key; |
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for (int level = (int)m_level; level >= 0; --level) |
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while (Cmp::Lt(*node->next[level]->key, key)) |
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node = node->next[level]; |
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node = node->next[0]; |
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if (node != m_stop && Cmp::Eq(*node->key, *m_stop->key)) { |
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if (tag) |
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*tag = node; |
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return node->object; |
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} |
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else { |
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if (tag) |
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*tag = nil; |
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return nil; |
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} |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::FindNext (SkipListTag * tag) const { |
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Node * node = (Node *)*tag; |
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m_stop->key = node->key; |
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for (int level = (int)node->level; level >= 0; --level) |
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while (Cmp::Lt(*node->next[level]->key, *m_stop->key)) |
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node = node->next[level]; |
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node = node->next[0]; |
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if (node != m_stop && Cmp::Eq(*node->key, *m_stop->key)) { |
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*tag = node; |
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return node->object; |
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} |
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else { |
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*tag = nil; |
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return nil; |
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} |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::Head (SkipListTag * tag) const { |
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ASSERT(tag); |
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Node * first = m_head->next[0]; |
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if (first == m_stop) { |
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*tag = nil; |
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return nil; |
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} |
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*tag = first; |
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return first->object; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::Next (SkipListTag * tag) const { |
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ASSERT(tag); |
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Node * node = (Node *)*tag; |
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ASSERT(node); |
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if (node->next[0] == m_stop) { |
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*tag = nil; |
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return nil; |
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} |
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*tag = node->next[0]; |
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return node->next[0]->object; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::Prev (SkipListTag * tag) const { |
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ASSERT(tag); |
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Node * node = (Node *)*tag; |
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ASSERT(node); |
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if (node->prev == m_head) { |
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*tag = nil; |
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return nil; |
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} |
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*tag = node->prev; |
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return node->prev->object; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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T * TSkipList<T,K,keyOffset,Cmp>::Tail (SkipListTag * tag) const { |
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ASSERT(tag); |
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Node * last = m_stop->prev; |
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if (last == m_head) { |
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*tag = nil; |
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return nil; |
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} |
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*tag = last; |
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return last->object; |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::Link (T * object) { |
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const K * key = (const K *)((const byte *)object + keyOffset); |
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// Find the node's insertion point |
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m_stop->key = key; |
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Node * update[kMaxLevels]; |
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Node * node = m_head; |
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for (int level = (int)m_level; level >= 0; --level) { |
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while (Cmp::Lt(*node->next[level]->key, *key)) |
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node = node->next[level]; |
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update[level] = node; |
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} |
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node = node->next[0]; |
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{ |
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// Select a level for the skip node |
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unsigned newLevel = RandomLevel(); |
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if (newLevel > m_level) { |
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if (m_level < kMaxLevels - 1) { |
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newLevel = ++m_level; |
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update[newLevel] = m_head; |
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} |
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else |
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newLevel = m_level; |
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} |
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// Create the node and insert it into the skip list |
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Node * node = AllocNode(newLevel); |
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node->key = key; |
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node->object = object; |
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for (unsigned level = newLevel; level >= 1; --level) { |
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node->next[level] = update[level]->next[level]; |
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update[level]->next[level] = node; |
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} |
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node->prev = update[0]; |
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node->next[0] = update[0]->next[0]; |
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update[0]->next[0]->prev = node; |
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update[0]->next[0] = node; |
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} |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::Unlink (T * object) { |
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const K * key = (const K *)((const byte *)object + keyOffset); |
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Node * node = m_head; |
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Node * update[kMaxLevels]; |
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int level = m_level; |
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for (;;) { |
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// Find the node being unlinked |
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m_stop->key = key; |
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for (; level >= 0; --level) { |
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while (Cmp::Lt(*node->next[level]->key, *key)) |
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node = node->next[level]; |
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update[level] = node; |
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} |
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node = node->next[0]; |
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// Node wasn't found so do nothing |
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if (*node->key != *key || node == m_stop) |
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return; |
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if (node->object == object) |
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break; |
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} |
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// Update all links |
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for (level = m_level; level >= 1; --level) { |
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if (update[level]->next[level] != node) |
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continue; |
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update[level]->next[level] = node->next[level]; |
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} |
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ASSERT(update[0]->next[0] == node); |
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node->next[0]->prev = update[0]; |
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update[0]->next[0] = node->next[0]; |
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// Update header |
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while (m_level && m_head->next[m_level] == m_stop) |
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--m_level; |
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FreeNode(node); |
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} |
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//============================================================================ |
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template<class T, class K, unsigned keyOffset, class Cmp> |
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void TSkipList<T,K,keyOffset,Cmp>::UnlinkAll () { |
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Node * ptr = m_head->next[0]; |
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while (ptr != m_stop) { |
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Node * next = ptr->next[0]; |
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FreeNode(ptr); |
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ptr = next; |
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} |
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m_stop->prev = m_head; |
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for (unsigned index = 0; index < kMaxLevels; ++index) |
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m_head->next[index] = m_stop; |
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m_level = 0; |
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}
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