DLList.hpp
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上传日期:2022-05-23
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文件大小:6k
- /* Copyright (C) 2003 MySQL AB
- This program 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 2 of the License, or
- (at your option) any later version.
- This program 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.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #ifndef DLLIST_HPP
- #define DLLIST_HPP
- #include "ArrayPool.hpp"
- #include <NdbOut.hpp>
- /**
- * Template class used for implementing an
- * list of object retreived from a pool
- */
- template <class T>
- class DLList {
- public:
- /**
- * List head
- */
- struct Head {
- Head();
- Uint32 firstItem;
- inline bool isEmpty() const { return firstItem == RNIL; }
- };
-
- DLList(ArrayPool<T> & thePool);
-
- /**
- * Allocate an object from pool - update Ptr
- *
- * Return i
- */
- bool seize(Ptr<T> &);
- /**
- * Allocate object <b>i</b> from pool - update Ptr
- *
- * Return i
- */
- bool seizeId(Ptr<T> &, Uint32 i);
- /**
- * Check if <b>i</b> is allocated.
- */
- bool findId(Uint32 i) const;
-
- /**
- * Allocate <b>n</b>objects from pool
- *
- * Return i value of first object allocated or RNIL if fails
- */
- bool seizeN(Ptr<T> &, Uint32 n);
- /**
- * Return an object to pool
- */
- void release(Uint32 i);
-
- /**
- * Return an object to pool
- */
- void release(Ptr<T> &);
- /**
- * Return all objects to the pool
- */
- void release();
- /**
- * Add object to list
- *
- * @NOTE MUST be seized from correct pool
- */
- void add(Ptr<T> &);
-
- /**
- * Remove object from list
- *
- * @NOTE Does not return it to pool
- */
- void remove(Ptr<T> &);
-
- /**
- * Update i & p value according to <b>i</b>
- */
- void getPtr(Ptr<T> &, Uint32 i) const;
-
- /**
- * Update p value for ptr according to i value
- */
- void getPtr(Ptr<T> &) const ;
-
- /**
- * Get pointer for i value
- */
- T * getPtr(Uint32 i) const ;
- /**
- * Update ptr to first element in list
- *
- * @return True if element exists, false otherwise
- */
- bool first(Ptr<T> &) const ;
- /**
- * Get next element
- *
- * @note ptr must have both p & i values
- *
- * @return True if element exists, false otherwise
- */
- bool next(Ptr<T> &) const ;
-
- /**
- * Check if next exists
- *
- * @note ptr must have both p & i values
- * @return True if element exists, false otherwise
- */
- bool hasNext(const Ptr<T> &) const;
- Uint32 noOfElements() const {
- Uint32 c = 0;
- Uint32 i = head.firstItem;
- while(i != RNIL){
- c++;
- const T * t = thePool.getPtr(i);
- i = t->nextList;
- }
- return c;
- }
- /**
- * Print
- * (Run operator NdbOut<< on every element)
- */
- void print(NdbOut & out) {
- Uint32 i = head.firstItem;
- while(i != RNIL){
- T * t = thePool.getPtr(i);
- t->print(out); out << " ";
- i = t->nextList;
- }
- }
- inline bool isEmpty() const { return head.firstItem == RNIL;}
-
- protected:
- Head head;
- ArrayPool<T> & thePool;
- };
- template<class T>
- class LocalDLList : public DLList<T> {
- public:
- LocalDLList(ArrayPool<T> & thePool, typename DLList<T>::Head & _src)
- : DLList<T>(thePool), src(_src)
- {
- this->head = src;
- }
-
- ~LocalDLList(){
- src = this->head;
- }
- private:
- typename DLList<T>::Head & src;
- };
- template <class T>
- inline
- DLList<T>::DLList(ArrayPool<T> & _pool):
- thePool(_pool){
- }
- template<class T>
- inline
- DLList<T>::Head::Head(){
- firstItem = RNIL;
- }
- /**
- * Allocate an object from pool - update Ptr
- *
- * Return i
- */
- template <class T>
- inline
- bool
- DLList<T>::seize(Ptr<T> & p){
- if(thePool.seize(p)){
- add(p);
- return true;
- }
- return false;
- }
- /**
- * Allocate an object from pool - update Ptr
- *
- * Return i
- */
- template <class T>
- inline
- bool
- DLList<T>::seizeId(Ptr<T> & p, Uint32 ir){
- if(thePool.seizeId(p, ir)){
- add(p);
- return true;
- }
- return false;
- }
- template <class T>
- inline
- bool
- DLList<T>::findId(Uint32 i) const {
- return thePool.findId(i);
- }
- template <class T>
- inline
- void
- DLList<T>::add(Ptr<T> & p){
- T * t = p.p;
- Uint32 ff = head.firstItem;
-
- t->nextList = ff;
- t->prevList = RNIL;
- head.firstItem = p.i;
-
- if(ff != RNIL){
- T * t2 = thePool.getPtr(ff);
- t2->prevList = p.i;
- }
- }
- template <class T>
- inline
- void
- DLList<T>::remove(Ptr<T> & p){
- T * t = p.p;
- Uint32 ni = t->nextList;
- Uint32 pi = t->prevList;
- if(ni != RNIL){
- T * t = thePool.getPtr(ni);
- t->prevList = pi;
- }
-
- if(pi != RNIL){
- T * t = thePool.getPtr(pi);
- t->nextList = ni;
- } else {
- head.firstItem = ni;
- }
- }
- /**
- * Return an object to pool
- */
- template <class T>
- inline
- void
- DLList<T>::release(Uint32 i){
- Ptr<T> p;
- p.i = i;
- p.p = thePool.getPtr(i);
- release(p);
- }
-
- /**
- * Return an object to pool
- */
- template <class T>
- inline
- void
- DLList<T>::release(Ptr<T> & p){
- remove(p);
- thePool.release(p.i);
- }
- template <class T>
- inline
- void
- DLList<T>::release(){
- while(head.firstItem != RNIL){
- const T * t = thePool.getPtr(head.firstItem);
- const Uint32 i = head.firstItem;
- head.firstItem = t->nextList;
- thePool.release(i);
- }
- }
- template <class T>
- inline
- void
- DLList<T>::getPtr(Ptr<T> & p, Uint32 i) const {
- p.i = i;
- p.p = thePool.getPtr(i);
- }
- template <class T>
- inline
- void
- DLList<T>::getPtr(Ptr<T> & p) const {
- thePool.getPtr(p);
- }
-
- template <class T>
- inline
- T *
- DLList<T>::getPtr(Uint32 i) const {
- return thePool.getPtr(i);
- }
- /**
- * Update ptr to first element in list
- *
- * Return i
- */
- template <class T>
- inline
- bool
- DLList<T>::first(Ptr<T> & p) const {
- Uint32 i = head.firstItem;
- p.i = i;
- if(i != RNIL){
- p.p = thePool.getPtr(i);
- return true;
- }
- p.p = NULL;
- return false;
- }
- template <class T>
- inline
- bool
- DLList<T>::next(Ptr<T> & p) const {
- Uint32 i = p.p->nextList;
- p.i = i;
- if(i != RNIL){
- p.p = thePool.getPtr(i);
- return true;
- }
- p.p = NULL;
- return false;
- }
- template <class T>
- inline
- bool
- DLList<T>::hasNext(const Ptr<T> & p) const {
- return p.p->nextList != RNIL;
- }
- #endif