/******************************************************************************** List.h*** By Patrick Wyatt - 5/16/2010****//******************************************************************************** WHAT IT IS** This module defines a linked-list implementation that uses "embedded"* links rather than separately allocated link-nodes as does STL and* more or less all other linked-list implementations.** Why is this cool:* 1. No additional memory allocations (malloc) required to link* an object into a linked list.* 2. Not necessary to traverse an additional pointer references* to get to the object being dereferenced.* 3. Probably most importantly, when objects get deleted, they* automatically unlink themselves from the lists they're* linked to, eliminating many common types of bugs.** HOW TO USE IT** Declare a structure that will be contained in one or more linked lists:* class CFoo {* LIST_LINK(CFoo) m_linkByData;* LIST_LINK(CFoo) m_linkByType;* int m_data;* int m_type;* ...* };** Declare list variables:* LIST_DECLARE(CFoo, m_linkByData) listByData;* LIST_DECLARE(CFoo, m_linkByType) listByType;* LIST_PTR(CFoo) m_listPtr = foo ? &listByData : &listByType;** Operations on links:* T * Prev ();* T * Next ();* void Unlink ();* bool IsLinked () const;** Operations on lists:* bool Empty () const;* void UnlinkAll ();* void DeleteAll ();** T * Head ();* T * Tail ();* T * Prev (T * node);* T * Next (T * node);** void InsertHead (T * node);* void InsertTail (T * node);* void InsertBefore (T * node, T * before);* void InsertAfter (T * node, T * after);** NOTES** Limitations:* All nodes must be allocated on (at least) two-byte boundaries* because the low bit is used as a sentinel to signal end-of-list.** Thanks to:* Something like this code was originally implemented by Mike* O'Brien in storm.dll for Diablo in 1995, and again at ArenaNet* for Guild Wars.****/#ifdef LIST_H#error "Header included more than once"#endif#define LIST_H/******************************************************************************** List definition macros****/// Define a linked list:// T = type of object being linked// link = member within object which is the link field#define LIST_DECLARE(T, link) TListDeclare<T, offsetof(T, link)>// Define a field within a structure that will be used to link it into a list#define LIST_LINK(T) TLink<T>// Define a pointer to a list#define LIST_PTR(T) TList<T> */******************************************************************************** TLink****///=============================================================================template<class T>class TLink {public: ~TLink (); TLink (); bool IsLinked () const; void Unlink (); T * Prev (); T * Next (); const T * Prev () const; const T * Next () const; // For use by list-type classes, not user code; // the alternative is to friend TList<T>, THash<T>, // and (eventually) many other structures. TLink (size_t offset); void SetOffset (size_t offset); TLink<T> * NextLink (); TLink<T> * PrevLink (); void InsertBefore (T * node, TLink<T> * nextLink); void InsertAfter (T * node, TLink<T> * prevLink);private: T * m_nextNode; // pointer to the next >object< TLink<T> * m_prevLink; // pointer to the previous >link field< void RemoveFromList (); // Hide copy-constructor and assignment operator TLink (const TLink &); TLink & operator= (const TLink &);};//=============================================================================template<class T>TLink<T>::~TLink () { RemoveFromList();}//=============================================================================template<class T>TLink<T>::TLink () { // Mark this node as the end of the list, with no link offset m_nextNode = (T *) ((size_t) this + 1 - 0); m_prevLink = this;}//=============================================================================template<class T>TLink<T>::TLink (size_t offset) { // Mark this node as the end of the list, with the link offset set m_nextNode = (T *) ((size_t) this + 1 - offset); m_prevLink = this;}//=============================================================================template<class T>void TLink<T>::SetOffset (size_t offset) { // Mark this node as the end of the list, with the link offset set m_nextNode = (T *) ((size_t) this + 1 - offset); m_prevLink = this;}//=============================================================================template<class T>TLink<T> * TLink<T>::NextLink () { // Calculate the offset from a node pointer to a link structure size_t offset = (size_t) this - ((size_t) m_prevLink->m_nextNode & ~1); // Get the link field for the next node return (TLink<T> *) (((size_t) m_nextNode & ~1) + offset);}//=============================================================================template<class T>void TLink<T>::RemoveFromList () { NextLink()->m_prevLink = m_prevLink; m_prevLink->m_nextNode = m_nextNode;}//=============================================================================template<class T>void TLink<T>::InsertBefore (T * node, TLink<T> * nextLink) { RemoveFromList(); m_prevLink = nextLink->m_prevLink; m_nextNode = m_prevLink->m_nextNode; nextLink->m_prevLink->m_nextNode = node; nextLink->m_prevLink = this;}//=============================================================================template<class T>void TLink<T>::InsertAfter (T * node, TLink<T> * prevLink) { RemoveFromList(); m_prevLink = prevLink; m_nextNode = prevLink->m_nextNode; prevLink->NextLink()->m_prevLink = this; prevLink->m_nextNode = node;}//=============================================================================template<class T>bool TLink<T>::IsLinked () const { return m_prevLink != this;}//=============================================================================template<class T>void TLink<T>::Unlink () { RemoveFromList(); // Mark this node as the end of the list with no link offset m_nextNode = (T *) ((size_t) this + 1); m_prevLink = this;}//=============================================================================template<class T>TLink<T> * TLink<T>::PrevLink () { return m_prevLink;}//=============================================================================template<class T>T * TLink<T>::Prev () { T * prevNode = m_prevLink->m_prevLink->m_nextNode; if ((size_t) prevNode & 1) return NULL; return prevNode;}//=============================================================================template<class T>const T * TLink<T>::Prev () const { const T * prevNode = m_prevLink->m_prevLink->m_nextNode; if ((size_t) prevNode & 1) return NULL; return prevNode;}//=============================================================================template<class T>T * TLink<T>::Next () { if ((size_t) m_nextNode & 1) return NULL; return m_nextNode;}//=============================================================================template<class T>const T * TLink<T>::Next () const { if ((size_t) m_nextNode & 1) return NULL; return m_nextNode;}/******************************************************************************** TList****///=============================================================================template<class T>class TList {public: ~TList (); TList (); bool Empty () const; void UnlinkAll (); void DeleteAll (); T * Head (); T * Tail (); const T * Head () const; const T * Tail () const; T * Prev (T * node); T * Next (T * node); const T * Prev (const T * node) const; const T * Next (const T * node) const; void InsertHead (T * node); void InsertTail (T * node); void InsertBefore (T * node, T * before); void InsertAfter (T * node, T * after);private: TLink<T> m_link; size_t m_offset; TList (size_t offset); TLink<T> * GetLinkFromNode (const T * node) const; template<class T, size_t offset> friend class TListDeclare; // Hide copy-constructor and assignment operator TList (const TList &); TList & operator= (const TList &);};//=============================================================================template<class T>TList<T>::~TList () { UnlinkAll();}//=============================================================================template<class T>TList<T>::TList () : m_link(), m_offset((size_t) -1){}//=============================================================================template<class T>TList<T>::TList (size_t offset) : m_link(offset), m_offset(offset){}//=============================================================================template<class T>bool TList<T>::Empty () const { return m_link.Next() == NULL;}//=============================================================================template<class T>void TList<T>::UnlinkAll () { for (;;) { TLink<T> * link = m_link.PrevLink(); if (link == &m_link) break; link->Unlink(); }}//=============================================================================template<class T>void TList<T>::DeleteAll () { while (T * node = m_link.Next()) delete node;}//=============================================================================template<class T>T * TList<T>::Head () { return m_link.Next();}//=============================================================================template<class T>T * TList<T>::Tail () { return m_link.Prev();}//=============================================================================template<class T>const T * TList<T>::Head () const { return m_link.Next();}//=============================================================================template<class T>const T * TList<T>::Tail () const { return m_link.Prev();}//=============================================================================template<class T>T * TList<T>::Prev (T * node) { return GetLinkFromNode(node)->Prev();}//=============================================================================template<class T>const T * TList<T>::Prev (const T * node) const { return GetLinkFromNode(node)->Prev();}//=============================================================================template<class T>T * TList<T>::Next (T * node) { return GetLinkFromNode(node)->Next();}//=============================================================================template<class T>const T * TList<T>::Next (const T * node) const { return GetLinkFromNode(node)->Next();}//=============================================================================template<class T>void TList<T>::InsertHead (T * node) { InsertAfter(node, NULL);}//=============================================================================template<class T>void TList<T>::InsertTail (T * node) { InsertBefore(node, NULL);}//=============================================================================template<class T>void TList<T>::InsertBefore (T * node, T * before) { ASSERT(!((size_t) node & 1)); GetLinkFromNode(node)->InsertBefore( node, before ? GetLinkFromNode(before) : &m_link );}//=============================================================================template<class T>void TList<T>::InsertAfter (T * node, T * after) { ASSERT(!((size_t) node & 1)); GetLinkFromNode(node)->InsertAfter( node, after ? GetLinkFromNode(after) : &m_link );}//=============================================================================template<class T>TLink<T> * TList<T>::GetLinkFromNode (const T * node) const { ASSERT(m_offset != (size_t) -1); return (TLink<T> *) ((size_t) node + m_offset);}/******************************************************************************** TListDeclare - declare a list with a known link offset****///=============================================================================template<class T, size_t offset>class TListDeclare : public TList<T> {public: TListDeclare ();};//=============================================================================template<class T, size_t offset>TListDeclare<T, offset>::TListDeclare () : TList<T>(offset){}//===================================// MIT License//// Copyright (c) 2010 by Patrick Wyatt//// Permission is hereby granted, free of charge, to any person obtaining a copy// of this software and associated documentation files (the "Software"), to deal// in the Software without restriction, including without limitation the rights// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell// copies of the Software, and to permit persons to whom the Software is// furnished to do so, subject to the following conditions://// The above copyright notice and this permission notice shall be included in// all copies or substantial portions of the Software.//// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN// THE SOFTWARE.//===================================
