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nsCList.h
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00001 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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00015  * The Original Code is mozilla.org code.
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00017  * The Initial Developer of the Original Code is
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00024  * Alternatively, the contents of this file may be used under the terms of
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00037 
00038 #ifndef CLIST_H
00039 #define CLIST_H
00040 
00041 #include <stddef.h>
00042 
00043 // -----------------------------------------------------------------------
00044 //
00045 // Simple circular linked-list implementation...
00046 //
00047 // -----------------------------------------------------------------------
00048 
00049 // Foreward declarations...
00050 struct CList;
00051 
00052 #define OBJECT_PTR_FROM_CLIST(className, listElement) \
00053             ((char*)listElement - offsetof(className, m_link))
00054                 
00055 
00056 struct CList {
00057     CList *next;
00058     CList *prev;
00059 
00060     CList() {
00061         next = prev = this;
00062     }
00063 
00064     ~CList() {
00065         Remove();
00066     }
00067         
00068     //
00069     // Append an element to the end of this list
00070     //
00071     void Append(CList &element) {
00072         element.next = this;
00073         element.prev = prev;
00074         prev->next = &element;
00075         prev = &element;
00076     }
00077 
00078     //
00079     // Add an element to the beginning of this list
00080     //
00081     void Add(CList &element) {
00082         element.next = next;
00083         element.prev = this;
00084         next->prev = &element;
00085         next = &element;
00086     }
00087 
00088     //
00089     // Append this element to the end of a list
00090     //
00091     void AppendToList(CList &list) {
00092         list.Append(*this);
00093     }
00094 
00095     //
00096     // Add this element to the beginning of a list
00097     //
00098     void AddToList(CList &list) {
00099         list.Add(*this);
00100     }
00101 
00102     //
00103     // Remove this element from the list and re-initialize
00104     //
00105     void Remove(void) {
00106         prev->next = next;
00107         next->prev = prev;
00108  
00109         next = prev = this;
00110     }
00111 
00112     //
00113     // Is this list empty ?
00114     //
00115     bool IsEmpty(void) {
00116         return (next == this);
00117     }
00118 };    
00119 
00120 #endif // CLIST_H
00121