99 lines
3.2 KiB
C++
99 lines
3.2 KiB
C++
/********************************************************
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* ██████╗ ██████╗████████╗██╗
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* ██╔════╝ ██╔════╝╚══██╔══╝██║
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* ██║ ███╗██║ ██║ ██║
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* ██║ ██║██║ ██║ ██║
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* ╚██████╔╝╚██████╗ ██║ ███████╗
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* ╚═════╝ ╚═════╝ ╚═╝ ╚══════╝
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* Geophysical Computational Tools & Library (GCTL)
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*
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* Copyright (c) 2023 Yi Zhang (yizhang-geo@zju.edu.cn)
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*
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* GCTL is distributed under a dual licensing scheme. You can redistribute
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* it and/or modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, either version 2
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* of the License, or (at your option) any later version. You should have
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* received a copy of the GNU Lesser General Public License along with this
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* program. If not, see <http://www.gnu.org/licenses/>.
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*
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* If the terms and conditions of the LGPL v.2. would prevent you from using
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* the GCTL, please consider the option to obtain a commercial license for a
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* fee. These licenses are offered by the GCTL's original author. As a rule,
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* licenses are provided "as-is", unlimited in time for a one time fee. Please
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* send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget
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* to include some description of your company and the realm of its activities.
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* Also add information on how to contact you by electronic and paper mail.
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******************************************************/
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#ifndef _GCTL_SPTR_H
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#define _GCTL_SPTR_H
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namespace gctl
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{
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//模板类作为友元时要先有声明
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template <typename T> class smart_ptr;
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//辅助类
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template <typename T>
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class ref_ptr
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{
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private:
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//该类成员访问权限全部为private，因为不想让用户直接使用该类
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//定义智能指针类为友元，因为智能指针类需要直接操纵辅助类
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friend class smart_ptr<T>;
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ref_ptr() : p(nullptr), count(0) {}
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//构造函数的参数为基础对象的指针
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ref_ptr(T *ptr) : p(ptr), count(1) {}
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//析构函数
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~ref_ptr() {delete p;}
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//引用计数
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int count;
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//基础对象指针
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T *p;
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};
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//智能指针类
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template <typename T>
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class smart_ptr
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{
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public:
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smart_ptr() : rp(new ref_ptr<T>()) {}
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smart_ptr(T *ptr) : rp(new ref_ptr<T>(ptr)) {} //构造函数
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smart_ptr(const smart_ptr<T> &sp) : rp(sp.rp) {++rp->count;} //复制构造函数
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smart_ptr &operator=(const smart_ptr<T>& rhs) //重载赋值操作符
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{
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++rhs.rp->count; //首先将右操作数引用计数加1，
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if (--rp->count == 0) //然后将引用计数减1，可以应对自赋值
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delete rp;
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rp = rhs.rp;
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return *this;
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}
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T &operator *() //重载*操作符
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{
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return *(rp->p);
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}
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T *operator ->() //重载->操作符
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{
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return rp->p;
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}
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~smart_ptr() //析构函数
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{
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if (--rp->count == 0) //当引用计数减为0时，删除辅助类对象指针，从而删除基础对象
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{
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delete rp;
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}
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}
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T *get()
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{
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return rp->p;
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}
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private:
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ref_ptr<T> *rp; //辅助类对象指针
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};
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};
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#endif //_GCTL_SPTR_H
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